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1. 38 38 442 Addressing 39 44 3 Repeaters and addresses operating in the same system 39 45 Message Routing a re SU NATA GINA 40 4 5 1 Message Routing Ga 42 4 5 2 Message Routing Limitations 42 45 3 Message Routing planning La ka ANA IGAN 43 4 5 4 SaTerm and Message Routing configuration 43 4 5 5 Manual Configuration enne enne 44 4 5 6 Operating modes of Message Routing 44 4 577 Network ID iuis eee 46 TESTS RESULTS AND ANALYSIS e reeeeeeeee mma nananana 47 5 1 Satelline 3AS Radio Modem eruere eu 47 Duel System Setup 47 51 2 48 5 1 3 Laboratory Tests a deis 48 Result Analysis 51 5 2 3G Based Technology 54 Du System AA CEDAR 55 222 245 ond 56 2 253 Test an ptu ob t ade eu eR cu cute 57 3 2 2 Result Analysts uode ortis DU
2. 19 3 AVAILABLE WIRELESS TECHNOLOGIES FOR REMOTE CONTROL IN ELECTRICAL NETWORKS SEA aedis 21 3 1 GSM Technology OverviIew 22 3 2 GPRS Technology OvervIew 23 3 3 3G Technology OVvervIew a 23 3 4 Normal Radio 24 4 RADIO FREQUENCY erra 26 4 1 Satelhine aaa 26 41 1 Satelline 3AS d Technical 27 4 1 2 Configuration and Installation eene 29 4 1 3 Interfaces and Connectors re 30 4 14 5 2821 31 4 2 RF Interface aa a 31 AD TYransmitfer asss alada 32 ADD ROCCIVOR duc 32 123 PAG RM One ae 32 4 3 Transparent Data Transmissions 33 4 3 1 Serial interface and data 33 4 3 2 Handshake Hn esS u aaa nl u Qu w Saa aa 35 4 3 3 Possible delays and timing during data transmission 35 4 4 Repeater Mode and Addressing
3. 26 SATEL Oy website SATELLINE 3AS V3 4 UK datasheet Accessed 11 6 2012 http www satel com userData satel downloads user guides satelline S ATELLINE 3AS V3 4 UK pdf chapter 5 page 41 27 SATEL Oy website SATELLINE 3AS V3 4 UK datasheet Accessed 11 6 2012 http www satel com userData satel downloads user guides satelline SATELLINE 3AS V3 4 UK pdf chapter 5 page 42 28 SATEL Oy website SATELLINE 3AS V3 4 UK datasheet Accessed 11 6 2012 http www satel com userData satel downloads user guides satelline SATELLINE 3AS V3 4 UK pdf chapter 3 page 35 29 SATEL Oy website SATELLINE 3AS V3 4 UK datasheet Accessed 11 6 2012 http www satel com userData satel downloads user guides satelline S ATELLINE 3AS V3 4 UK pdf chapter 5 page 45 69 30 SATEL website SATELLINE 3AS V3 4 UK datasheet Accessed 11 6 2012 http www satel com userData satel downloads user guides satelline SATELLINE 3AS V3 4 UK pdf chapter 6 page 47 131 SATEL Oy website SATELLINE 3AS 4 UK datasheet Accessed 11 6 2012 http www satel com userData satel downloads user guides satelline SATELLINE 3AS V3 4 UK pdf chapter 6 page 48 32 SATEL Oy website SATELLINE 3AS 4 UK datasheet Accessed 11 6 2012 http www satel com userData satel downloads user guides satelline SATELLINE 3AS V3 4 UK pdf chapter 6 page 51 33 SATEL Oy website SATELLINE 3AS 4 UK datasheet
4. 59 CONCLUSIONS AND RECOMMENDATIONS eee 65 REFERENCES o m naa AAO 67 LIST OF FIGURES AND TABLES Figure 1 Power distribution network from Power generation to Metering 12 Figure 2 Technical description of electrical power network wireless moni toring 13 Figure 3 Hydroelectric power substation 15 Figure 4 Pole mounted Recloser 16 Figure 5 An old pole mounted Disconnector 17 Figure 6 A pole mounted Distribution Transformer 18 Figure 7 Satelline 3 5 radio modem 26 Figure 8 SATELLINE 3AS message routing network structure 41 Figure 9 TX data signal capture 49 Figure 10 Data packet transmission delay zoomed in 49 Figure 11 TX and RX data signal capture 50 Figure 12 Poll and Reply sequence 50 Figure 13 Transmitted request data format 51 Figure 14 Client Server emulation program output beginning 58 Figure 15 client server emulation output and average RTT 59 Figure 16 Packets sent against Packets Loss 61 Figure 17 Average RTT against Packets Loss 61 Figure 18 distribution with respect to frequency 62 Table 1 Technical specifications of SATELLINE 3AS radio modem 11 29 Table 2 Installation settings and configuration 12 30 Table 3 Data format example 34 Table 4 Handshake lines 27 35 Table 5 SATTELINE 3AS message routing operating modes 45 Table 6 Packets sent received and loss with average RTT 61 ABBREVIATIONS RMU SCADA
5. guides satelline SATELLINE 3AS V3 4 UK pdf chapter 3 page 25 19 SATEL Oy website SATELLINE 3AS V3 4 UK datasheet Accessed 11 6 2012 http www satel com userData satel downloads user guides satelline SATELLINE 3AS V3 4 UK pdf chapter 3 page 26 20 SATEL Oy website SATELLINE 3AS V3 4 UK datasheet Accessed 11 6 2012 http www w satel com userData satel downloads user guides satelline SATELLINE 3AS V3 4 UK pdf chapter 3 page 27 21 SATEL website SATELLINE 3AS V3 4 UK datasheet Accessed 11 6 2012 http www satel com userData satel downloads user guides satelline SATELLINE 3AS V3 4 UK pdf chapter 3 page 28 22 SATEL Oy website SATELLINE 3AS 4 UK datasheet Accessed 11 6 2012 http www satel com userData satel downloads user guides satelline SATELLINE 3AS V3 4 UK pdf chapter 3 page 29 23 SATEL Oy website SATELLINE 3AS V3 4 UK datasheet Accessed 11 6 2012 http www satel com userData satel downloads user guides satelline SATELLINE 3AS V3 4 UK pdf chapter 3 page 30 24 SATEL Oy website SATELLINE 3AS V3 4 UK datasheet Accessed 11 6 2012 http www satel com userData satel downloads user guides satelline S ATELLINE 3AS V3 4 UK pdf chapter 4 page 37 25 SATEL Oy website SATELLINE 3AS V3 4 UK datasheet Accessed 11 6 2012 http www satel com userData satel downloads user guides satelline S ATELLINE 3AS V3 4 UK pdf chapter 4 page 39
6. UDP HSPA RTT GPRS GSM 3G TDMA UMTS PRN CDMA VPN EMC TETRA EDGE Ring Main Unit Supervisory Control And Data Acquisition International Electrotechnical Commission User Datagram Protocol High Speed Packet Access Round Trip Time General Packet Radio Service Global System for Mobile Communication 3 Generation Time Division Multiple Access Universal Mobile Telecommunication System Private Radio Network Code Division Multiple Access Virtual Private Network Electromagnetic Compatibility Terrestrial Trunked Radio Enhanced Data rate for GSM Evolution 1 INTRODUCTION The world of today is called a global village and that is because what could not have been done within months if not years some decades back are accomplished within few seconds Data is readily available to be processed into information and then to be used for different purposes These pieces of information are gathered through media such as air wireless and cable wired and then processed into complete and meaningful information In this project the aim is to take a brief look into how data other than just voltages of electricity are sent to and received from power base stations and research into the possibility of using 3G technology in a bid to monitor and control power transmission networks from the power sta tions until it gets to the final consumers We are coming from an era of electrical power distribution where min
7. will be emptied and data retransmission of data will be issued Similar procedure is followed in the reception mode And this makes the data transmission speed stay the same A pause is defined as a time when there is no visible status change on the RS 232 interface TD line The modems are designed to recognize a pause when it happens on the serial line The pause detection is used to determine End of radio transmission SL command recognition User address recognition Pause is a major parameter in asynchronous data communication because it is originally used to separate serial messages from each other But as non real time operating systems get commonly used on PCs more random pauses are being added to data transmission The addition of these extra pauses may cause signifi cant problems most importantly in networks of several repeater stations To min imize this kind of unexpected problem which might sprung up at any time as a result of accumulated pauses it is possible to match the operation of the radio modem to the user data by simply adjusting the length parameter on through the programming menu using any value between 3 and 255 characters with 3 charac ters as the default value It is however important to note that the pause length time absolutely depends on the serial port settings And the maximum absolute time is always 170ms regard less of the value given during set up There is a direct relationship in the pause
8. length and the round trip delay of the radio link 29 4 44 Repeater Mode and Addressing 4 4 1 Repeater The radio modem can also operate as a repeater Serving as an intermediary and connecting device simply to relay data packet to the nearest radio modem con nected to it there by extending the coverage area of the network The radio modem is enabled to work as a repeater by settings from the Program ming Mode When working as a repeater decisions are independently made and the maximum size of repeated data is the same as that which can be buffered into the internal buffer memory before overflow is attained 1kB The radio modem needs only power supply and a suitable antenna to function as a repeater after all necessary settings have been made When in repeater mode it can transmit and receive data packet The only differ ence between an ordinary radio modem and the radio modem functioning as a re peater is that all data received from the serial interface will be buffered first into the internal buffer memory and then using the same channel with which the packet was received to re transmit it Otherwise it will function normally like any other radio modem We may have several repeaters working under a single base station forming a network of repeaters and base station This may be in chain like configuration meaning the repeaters are linked together in a chain like structure and transmit information from one to the other Thes
9. spective wireless modems wherever they may be so far they are properly confi g ured and are within the coverage range The information sent and received are created structured and formatted depending on the type of interfacing devices working on the various electrical infrastructure responsible for the various phase of electrical power distribution as in the one described in the figure 2 above more also depend on the IEC protocol with which it is configured and running These interfacing devices for example the ABB REC523 which is directly con nected to the power cable transmitting the electrical power has been hard coded and configured to work on IEC 60870 5 101 protocol in a way that it has address es for all the available electric cable carrying voltage connected to it and transmits bits of data based on the events happening on it to the control room remotely via a wireless modem for example the Satelline radio frequency modem one of those making ways in Finland today 21 3 AVAILABLE WIRELESS TECHNOLOGIES FOR MOTE CONTROL IN ELECTRICAL NETWORKS Transmitting encrypting and deciphering of data could be done using any of the suitable existing backbone technologies available today Some of these available technologies are TETRA GSM GPRS 3G Normal radio frequency modems etc The most commonly used and currently still in use for the purpose of transmitting intelligent safety information passing through overhead
10. viola_case_final pdf
11. Accessed 11 6 2012 http www satel com userData satel downloads user guides satelline SATELLINE 3AS V3 4 UK pdf chapter 7 page 54 134 SATEL Oy website SATELLINE 3AS 4 UK datasheet Accessed 11 6 2012 http www satel com userData satel downloads user guides satelline SATELLINE 3AS V3 4 UK pdf chapter 7 page 55 35 SATEL Oy website SATELLINE 3AS 4 UK datasheet Accessed 11 6 2012 http www satel com userData satel downloads user guides satelline S ATELLINE 3AS 4 UK pdf chapter 7 page 56 36 SATEL Oy website SATELLINE 3AS 4 UK datasheet Accessed 11 6 2012 http www satel com userData satel downloads user guides satelline S ATELLINE 3AS V3 4 UK pdf chapter 7 page 58 37 SATEL Oy website SATELLINE 3AS 4 UK datasheet Accessed 11 6 2012 http www satel com userData satel downloads user guides satelline SATELLINE 3AS V3 4 UK pdf chapter 7 page 61 38 ABB website IEC 60870 5 101 Unbalanced Remote Communication Proto col for REC 523 Technical Description Accessed 15 6 2012 http www05 abb com global scot scot229 nsf veritydisplay f466922a02ab837bc 2256fc600361bc8 Sfile rec523 IECprotENe pdf 71 39 Harri Jaskari 2012 Interview by Afolabi Ibrahim University of Ap plied Sciences Technobothnia 17th July 40 Viola systems website Accessed 1 12 2012 http www violasystems com sites default files viola_assets pdf abb kss
12. Message Routing OFF Serial Interface Type RS 232 or RS 422 or RS 485 Table 2 Installation settings and configuration 12 4 1 3 Interfaces and Connectors The Satelline radio modem is a DCE Data Communication Equipment which has a 15 pin D type female connector and includes all necessary connections needed to establish communication between the radio modems and computers act ing as DTE Data Termination Equipment Also considered during its design are all necessary EMC Electro Magnetic Compatibility requirements in accordance with the standard set by the destination authorities It is designed with two serial ports port 1 and 2 of which only one can be used at a time for communication Port 1 on the one hand complies with the RS 232 31 standard while Port 2 on the other hand is designed to work as 3 in 1 port in that it support either RS 232 RS 422 or RS 485 standards And the type of interface it has is set based on customer s want and can be later changed by the user from the programming mode 4 1 4 RS 232 Interface The RS 232 is a standard that defines the method of serial data transfer between a computer and its hardware peripherals This definition includes both the interface types and signal levels and is present in most computers and peripherals The RS 232 standard uses transmission lines in which each single signal line level is con nected to a common ground level It is designed
13. Packet Loss Sent received RTT Losses rate 1398 1379 62 8289 19 1 359084 1411 1406 68 2596 5 0 354359 1401 1386 71 5094 15 1 070664 1403 1394 62 7984 9 0 641483 1405 1400 70 8779 5 0 355872 1400 1394 62 9857 6 0 428571 1398 1396 61 4756 2 0 143062 1402 1394 73 7791 8 0 570613 1399 1392 62 3111 7 0 500357 1397 1386 73 0613 12 0 858984 Table 6 Packets sent received and loss with average RTT 61 Packet sent Packet Losses Packet sent Figure 16 Packets sent against Packets Loss AVE RTT E Packet Losses Figure 17 Average RTT against Packets Loss DISTRIBUTION CHART 600 500 400 Frequency 300 200 100 Figure 18 RTT distribution with respect to frequency An average of approximately 1401 packets were sent ten times within 15 40 and 21 00 and a total average packet loss of 8 8 was recorded Meaning it is safe to say atleast less than 1 0 63 of every 1401 packets sent through the 3G modem may not be received provided that the round trip delay time is up to an average of approximately 67ms Though there seem not to be a direct relationship 63 between the number of packets sent and number of packet loss recorded at any particular point in time This is evident on line 1 and 7 of the table where 1397 packets were sent in both cases and 19 packets was lost in the first case whilest in the other case only 2 packets loss was recorded which wa
14. polling characteristic of the SATELLINE 3AS modem I would say it is time for ABB to go 3G Every task in life comes with its own challenges with no exception to this project work A major challenge suffered is the inadequate flow of information between the project researcher and the company which brought the research to a halt at a point in time Perhaps as a result of confidentiality of the information of third par ty company Another would be the lack of financial resources which limits the amount of data collected through the simulation application with which the RTT and amount of packet loss was recorded The results from the simulation of the 3G technology would have been more cred ible probably if all other factors affecting the RTT in the medium are determined and kept constant and the program was run for more than 10 times considering different times of the day however with that in mind it is still safe enough to opine that ABB should migrate to 3G technology instead of a 2 5G or GPRS tech nology for their automation monitoring of electric power networks First the data transfer rate of 3G technology is higher thereby enhancing the RTT of the data transmitted the link reducing data packet loss Second support for 3G are becoming more and more than before thereby reducing prices of 3G modems on the market Third as companies grow and go into the future varieties of chal lenges come up and are tackled with re
15. 1403Packets Sent 1394 Packets Received 9 Packets Loss Average rtt 62 7984 Figure 15 client server emulation output and average RTT 5 2 4 Result Analysis The program was run on ten separate occasions each with varying amounts of packets sent and received and each output was recorded in separate text files AII sent packets revolved around approximately 1400 packets and the RTT was rec orded for each packet in milliseconds afterwards an average RTT of all returned packets was then calculated at the end of the program Packet losses were also considered because since this is a UDP datagram packet losses are bound to hap pen and ordinarily it might not have been noticeable if there were very few pack ets sent over the network but since there were relatively many packets to be sent and we have absolutely no control over the link especially on the server s side packet loss actually happened and this could be as a result of a number of reasons which traffic congestion of the transmission link is one of them and can be seen in both figures 14 and 15 above It will be interesting to see the behavior of the transmission medium for all the ten outputs taken from the ten separate run of the program Each packet is made up of 32bytes The table below shows the total number of packets sent the average RTTs for each and the total number of packets losses recorded Packet Packet AVE
16. ABB MicroScada application 5 1 22 Test arrangements Since I used the electrical engineering department of the school in Technobothnia there is an already existing setup connection of the Recloser Disconnector with the desktop computer serving as the central controlling station having the ABB MicroScada application the main system controller installed on it Connection of the RS 232 Bridge between the RS 232 interface connected to the desktop com puter and that of the SATELLINE 3AS radio modem was made appropriately After that was done the next thing was to read the transmitted and received in formation And this was done by connecting tiny pin like copper cable through the ports available on the RS 232 Bridge to the oscilloscope via its probing cable for signal detection and measurements The pin like copper cables were connected to the TX and RX port respectively and then both probes were grounded appropri ately Measurements were taking of the transmitted and received signals respectively and all necessary delays were noted 5 1 3 Laboratory Tests Results The following images were the results captured during the laboratory test from the oscilloscope The results of the transmitted data first then the received data and then both together are presented below In these images there are colour makers The signal in yellow colour represents the message sent from the control station central control room and that in green colour represen
17. It is a digital cellular technology used for transmitting mobile voice and data services The name GSM is a standardization group established in 1982 to create a common European mobile telephone standard This standard is the most vastly accepted standards and is implemented globally GSM is a second generation 2nd technology based on circuit switched system that divides each 200kHz channel into eight 25kHz time slots It operates in the 900MHz and 1 8GHz bands in Europe and the1 9GHz and 850MHz bands in the US The GSM is a digital technology developed with the capability to carry 64kbps bits per se cond to 120kbps of data rates It uses a narrow band TDMA technique for signal transmission Apart from the normal voice service GSM also provides data ser vices including Roaming ability to use an individual s own phone number in an other GSM network service This breakthrough in terms of acceptance made GSM most widely used cellular technology system having more than 70 percent of the world s digital cellular subscribers 3 23 One of the reasons behind its development was to provide a spectrum efficient technology better than the previous first generation analogue telephone system And this aim was achieved through the use of TDMA The use of this method en abled the accommodation of more users within the available frequency band In addition data encryption of the digitally encoded speech was also adopted in other to enhance privac
18. Virtual Mode Routing These two modes operate differently in the following ways shown in the table be low 45 Property Source Mode Routing Virtual Mode Routing Summary Slower more functions Faster less functions Radio interference Yes over hop function No tolerance Support for mobile Yes No stations Addition of substations to a network Only master station needs to be reconfigured Master station and con secutive repeaters need to be reconfigured Changing routes Only master station needs to be reconfigured All radio modems need to be reconfigured Maximum length of 16 hops No limit routes Over hop function Yes No Network ID Yes Yes Storing of routing Centralized Dispersed Information Message Routing 10 2 x number of hops 9 overhead bytes Maximum length of user protocol message bytes IkB Message Routing overhead IkB Message Routing overhead Table 5 SATTELINE 3AS message routing operating modes Both modes operate commonly in the following ways maximum number of terminal it can support depends on the network structure and the number of available routes A radio modem may have more than one terminal addresses in its address table The radio modem can support only four bytes hexadecimal of terminal ad dress length FFFFFFFF The radio modem as said earlier has a maximum of two bytes hexa
19. are common phenomenon experienced during data transmission And they are formed during inter switching of system from one state to the other For ex ample delays are formed when a system switches from Standby Mode to Data Transfer Mode and from Data Reception Mode to Data Transmission Mode The se delays are formed within the radio modem circuitry and on the radio interface When using a radio modem where it is possible to set the TX delay to values tween 1 and 65000ms it is advisable to do so because it helps prevent data con tention in the radio data modem Since the priority is it is logical that the ra dio modem would be prevented from switching into data reception during the TX delay and all data sent to the radio modem from the terminal would be buffered into a memory until the end of the TX delay This is a very important utility be cause it helps prevent data collision which could otherwise arise from too many radio modems answering to the polling of a base station at the same time SATELLINE modem needs to have TX Delay 50ms or more in order to avoid messages from colliding in case it is to be placed in a Pacific Crest system that uses addressing and acknowledging scheme 28 Data buffering happens basically when a radio modem is sending data to a second modem but the second modem is not ready to receive the sent data which could be that it is still in data transmission mode and not reception Usually at the sta
20. average Operating Temperature 25 C 55 C 40 C 75 C absolute min Range max Storage Temperature Range 40 C 85 C Antenna Connector TNC 50ohm female Housing Aluminum enclosure Size Hx Wx D 137 x 67 x 29mm Installation Plate 130 x 63 x Imm Weight 260g Table 1 Technical specifications of SATELLINE 3AS radio modem 11 4 12 Configuration and Installation The following default settings are found readily configured on the radio modem as at the point of shipment FIXED SETTINGS DEFINED AT THE TIME OF SHIPPING Radio Frequency Range In accordance with Customer Order and taking into account the regulations set by the local authorities between 330 470MHz Channel Spacing 12 5 20 or 25 kHz apart from the 869 MHz which must be 25kHz ADJUSTABLE SETTINGS Radio Settings 1W 3AS 112 dBm 25kHz 114 dBm 12 5kHz Addressing RX address OFF TX address OFF Serial Port 1 ON 19200 8bit data None 1 stop bit for 12 5kHz the default data speed is 9600 bps Serial Port 2 OFF 19200 8bit data None 1 stop bit for 12 5kHz the default data speed is 9600 bps Handshaking CTS Clear to send CD RSSI threshold RTS Ignored Additional settings Error correction OFF Error check OFF Repeater OFF SL Commands OFF Priority TX Routing OFF Tests OFF
21. currently in operation today To be investigated in this thesis work are the remaining wireless technologies mentioned above except TETRA namely GSM GPRS 3G and Normal radio frequency These four are going to be researched as far as the resources available for this project can go and the technicalities behind them Developed devices which are using these technologies and are already in use today basically for the purpose of transmitting wireless data conveyed on electrical networks for the monitoring and control of the electrical distribution system shall be intrinsically researched as well A major device which will be focused upon is the SATELLINE radio modems produced and manufactured by Satel Oy Finland and then I shall also research the probability of adopting a 3G based technology system in doing similar job as the SATELLINE radio modems To be discussed also are the backbone protocols upon which the proper functioning of the devices are built Tests will be carried out to confirm if the devices actually functions ex actly the way stipulated in the protocol s specifications documentation and con forms to it And data samples shall be collected from tests and used to support my claims as it will be made in the conclusions of this report 3 1 GSM Technology Overview GSM stands for Global System for Mobile communication It is an idea which emerged from the cell based mobile radio systems at Bell Laboratories about four decades ago
22. electrical power cable be it public or private of these technologies are about three namely GSM GPRS and Normal radio frequency TETRA is exempted because it s no longer in use today because there are no more development support for it be it from private or public organization though it is still in use by some government agencies in Finland e g the Finnish Fire Service 4 TETRA which stands for Terrestrial Trunked Radio and formerly known as Trans European Trunked Radio is a professional mobile radio and a transceiver popularly called walkie talkie It was a standard whose first version was published in 1995 by European Telecommunications Standard Institute It is widely in use across the world and in full usage and deployment in up to about 114 countries cutting across almost all the seven know continents in the world today TETRA as a wireless technology will not be discussed at length in this report due to the following setbacks it suffers since its development which makes it not so suitable for the purpose of this project work TETRA is a technology which is de signed to use a linear amplifier for a proper function as a radio frequency service provider technology It was also designed to transfer data at a rate of 7 2kbps per timeslot with a throughput of 3 5kbpslot of net packet According to the standard the latest version is said to support up to 115 2 kbps a 25kHz channel but in reality no networks with such data rate in is
23. only used in repeater application The address used by the radio modem for transmission of data will be determine by that which is used for the reception of the same data packet when working as a repeater if only one address pair is needed in a network both addresses must be set the same TX1 2 and RX1 RX2 The address is made up off 2 characters 16bit making available more than 65000 different addresses to be selected from When working in addressing mode the addresses are attached to the beginning of every sent packet by the repeater radio modem When these packets are received the first two characters will be checked just to be sure the packet arrived at the correct destination 31 4 4 3 Repeaters and addresses operating in the same system In a system where there are several repeaters single base station and a substation addresses must be used in radio modems Since the main objective of introducing addressing in the first place is to avoid data collision in a system of several repeat ers however there is no need for addresses for such systems with just one repeat er In this case the base station will receive messages from both the substation and repeater In a nutshell there are duplicated messages moving along the route 32 4 5 Message Routing Message routing is an important utility in SATELLINE 3AS and Epic modem range This essential feature makes automatic routing of data packet from a termi n
24. routing network It is simple to use and very quick for implementing a network design It uses graphical representation to depict network configuration on the screen This is done basically in three steps A graphical representation of the network is created on the screen which shows all the radio modems and their various positions in the network The settings are defined in the drawing The settings on each of the modems can now be uploaded to real radio mo dems by simply connecting them one by one to the COM port first they have to be in Programming Mode and then clicking the transmit button of SaTerm will initial the upload of the settings 35 4 5 5 Manual Configuration It is also possible to configure the radio modem manually to achieve message routing through the programming menu However this is only recommended when designing a very simple network structure or if some special definitions has to be made and such functions are not possible to draw using the SaTerm pro gram Otherwise it is highly encouraged to use the SaTerm program to first simu late the design and then upload it to the real radio modems In any case there must be a clear understanding of the operation of the Message Routing structure before an eventual manual configuration is made 35 4 5 6 Operating modes of Message Routing SATELLINE 3AS radio modem support two operating modes of message routing and they are Source Mode Routing
25. to make the massage end to the address There is no room for simultaneous transmission of messages since it is so simple that there can only be a message in the network at a time 43 The hardware and software version running on the devices determine the maximum number of routes available for messages During Message Routing the operation of the traditional Tx Rx addresses is automatically blocked 34 4 5 3 Message Routing planning It is essential to carefully and meticulously layout precise plans for the design of any radio modem system The set of devices location for installation installation proper and maintenance e t c must be clearly and carefully chosen After these have been achieved the Message Routing for the system can then begin Planning your message routing system Decide the mode of Message Routing which is best for your system Either Source Mode or Virtual Mode Layouts of the system should be designed The layout should include pa rameters such as protocol addresses of the terminal equipment radio fre quencies e t c The radio modems should be configured according to the laid out plans The configuration of parameters related to Message Routing can be done in two ways i Using SaTerm PC program ii Manual configuration in the setup menu 35 4 5 4 SaTerm and Message Routing configuration SaTerm is a desktop application used for the configuration and design of message
26. to transfer data wirelessly through a range of tens of kilometers They are used by private organization to create Pri vate Radio Networks PRN Private radio networks are used in industrial stand ard applications when it comes to and has to do with real time data communica tion Radio data modem can be independently operated making it possible not to totally rely on telecommunication or satellite network operators Operating the radio modems and making them communicate happens through allotted licensed frequencies either in UHF or VHF band These licensed frequencies are reserved for registered users in certain area in a way to avoid as much radio interference as possible from other Radio Frequency transmitters Usually this licensed frequen cy is available for free in most countries which enable easy implementation but the same frequency can be used by other users Radio modems are usually used by Land survey differential GPS Automated Meter Reading AMR SCADA appli 25 cations utility distribution networks fleet management applications telemetry applications etc Radio performance mostly plays a major role in making data transfer highly reliable Radio performance is generally influenced by the height of the antenna and type the sensitivity of the radio how much power it can pro duce as output and the design and efficiency of the entire system design 4 RADIO FREQUENCY In this part I shall focus the radio
27. 16 180966916 recv seq 16 rtt 47 180967321 seqno 17 gt gt gt 180967368 recv seq 17 rtt 47 180967789 seqno 18 180967836 recv seq 18 rtt 47 180968257 seqno 19 180968304 recv seq 19 rtt 47 180968725 seqno 20 180968772 recv seq 20 rtt 47 180969193 seqno 21 gt gt gt 180969256 recv seq 21 rtt 47 180969661 seqno 22 180969708 recv seq 22 rtt 47 180970129 seqno 23 gt gt gt 180970176 recv seq 23 rtt 47 180970597 seqno 24 gt gt gt 180970644 recv seq 24 rtt 47 180971065 seqno 25 180971128 recv seq 25 rtt 47 180971533 seqno 26 180971596 recv seq 26 rtt 47 180972001 seqno 27 180972064 recv seq 27 rtt 47 180972469 seqno 28 180972516 recv seq 28 rtt 47 180972937 seqno 29 180972984 recv seq 29 rtt 47 180973405 seqno 30 gt gt gt 180973468 recv seq 30 rtt 63 180973873 seqno 31 gt gt gt 180974341 seqno 32 gt gt gt 180974435 recv seq 32 rtt 94 120074436 aenm 31 rrr 54Q Figure 14 Client Server emulation program output beginning 59 181601497 seqno 1372 gt gt gt 181601543 1372 rtt 46 181601965 seqno 1373 gt gt gt 181602027 recv seq 1373 rtt 62 181602433 seqno 1374 gt gt gt 181602495 recv seq 1374 rtt 46 181602901 seqno 1375 181602963 recv seq 1375 rtt 62 181603369 seqno 1376 gt gt gt 181603415 recv seq 1376 rtt 46 181603837 seqno 1377 gt gt gt 181603883 recv seq 1377 rtt 46 181604305 seqno 1378 gt gt gt 181604383 r
28. 2012 http www satel com userData satel downloads user guides satelline S ATELLINE 3AS V3 4 UK pdf chapter 1 page 13 112 SATEL Oy website SATELLINE 3AS 4 UK datasheet Accessed 11 6 2012 http www satel com userData satel downloads user guides satelline SATELLINE 3AS V3 4 UK pdf chapter 1 page 16 13 SATEL Oy website SATELLINE 3AS V3 4 UK datasheet Accessed 11 6 2012 http www satel com userData satel downloads user guides satelline SATELLINE 3AS V3 4 UK pdf chapter 2 page 20 14 SATEL Oy website SATELLINE 3AS 4 UK datasheet Accessed 11 6 2012 http www satel com userData satel downloads user guides satelline SATELLINE 3AS V3 4 UK pdf chapter 2 page 21 15 SATEL Oy website SATELLINE 3AS V3 4 UK datasheet Accessed 11 6 2012 http www satel com userData satel downloads user guides satelline SATELLINE 3AS V3 4 UK pdf chapter 2 page 22 16 SATEL Oy website SATELLINE 3AS V3 4 UK datasheet Accessed 11 6 2012 http www satel com userData satel downloads user guides satelline SATELLINE 3AS V3 4 UK pdf chapter 2 page 23 17 SATEL Oy website SATELLINE 3AS 4 UK datasheet Accessed 11 6 2012 http www satel com userData satel downloads user guides satelline SATELLINE 3AS V3 4 UK pdf chapter 3 page 24 18 SATEL Oy website SATELLINE 3AS V3 4 UK datasheet Accessed 11 6 2012 http www satel com userData satel downloads user
29. PX VAASAN AMMATTIKORKEAKOULU NG VASA YRKESHOGSKOLA UNIVERSITY OF APPLIED SCIENCES Ibrahim Afolabi CONSIDERATION OF USING 3G CEL LULAR NETWORK TO MONITOR ABB S REMOTE CIRCUIT BREAKERS Technology and Communications 2012 UNIFASITY ILEIWE GIGA TI ILU VAASA Eko Imo Ayara bi Asa AKORI ORO Onkowe Ibrahim Afolabi Akole Igbeyewo lilo 3J lati fi se isakoso awon ero tin da ina duro titi ABB Odun 2012 Ede Yoruba Ojuewe Aarun din logorin Oruko Alabojuto Chao Gao Alekun ninu ibeere fun agbara fun elo ile ati ileise to n sheda nkan ti se okunfaa to yara kankan to si ogbogba ninu imuwa agbara itan ina ni lati le dojuko opo elo ati ibeere to be fun itan ina eka to peye ati ifikun itan ina gbodo wa nile lati ibujoko to n mu agbara itan ina lo si odo awon ti yoo lo ni ile ibi ishe ati awon ile ishe ton sheda nkan Asheyori ishe lai fi alafia ati ibolowo ewu sere je ohun ti o doju 1 ko awon oludasile agbara itan ina Bere lori eto eka itan ina titide bibojuto ati idari awon ibujoko itan ina oniranran pelu awon ogba imu ina wa kereje kereje kii se ise kekere rara Atagba ifisu otelemuye ti oyato si kilofolt pelu awon okun ina alagbara to se regi nla ati kukuru je ohun ti o doju ija ara beelo lilo ona omiran lati se atagba awe oro jeyo paapa julo siso oro lai lo okun tin gbe ohun ranshe ninu afefe Ona abayo akoko ti ABB lo ni Radio frequency modem Eyi k
30. al device over radio modems network to the destination recipient terminal Below is a step by step brief description of the routing functions of the SATELLINE 3AS radio modem Radio modem will read the message coming from the nearest terminal s connected to it The modem then checks and finds the terminal address of the recipient The radio modem will go through its internal routing table to see if there is any information about the address just found from the terminal device The radio modem will now modify the data by adding more address infor mation to it and then transmit it The transmitted radio frame will include o The network id o The route information The original user message encapsulated o And the redundant information such as checksums for error check ing e t c Any radio modem found on the route will relay this radio frame over the network to the radio modem which the destination address shows 41 The validity of the received message at the destination is checked and then the original message is extracted which is then finally sent to the terminal directly connected to it Below is a figurative demonstration of a possible structure of a radio modem mes sage routing network Figure 8 SATELLINE 3AS message routing network structure Base station Central station or Master station Repeater station S Sub station or Slave station Terminal devices Mobile s
31. and re ceived packets on the figure The markers X1 and X2 are approximately third 6 67ms and one fourth Sms of each grid division Sticking to and X2 convention where X1 still maintains its original value 0 0s for convenience and carefully looking at the positions of those makers with respect to the grid line division of time on the figure 20ms per division we would have an approximate answer as below Atx X2 0 0000ms 58 33ms 58 33ms Figure 12 above shows the nature of the message exchange between the central controlling station and the controlled station Most especially the third form of supported information service REQUEST RESPOND for data polling A situa tion whereby requests are sent at timely intervals from controlling stations to con trolled stations and corresponding replies response are returned containing ex pected information fulfilling the wish of each requests at their expected times of arrival These series of requests and replies are depicted in the capture in figure 12 This analysis will be incomplete without a proper investigation of what makes up the packet that is sent and received A proper analysis of the data packet format will give us more insight into the stream of data bits that flows through the link layer of the protocol as shown in figure 13 above Sadly this is something that has been hard coded on the protocol stack and is not made open perhaps for
32. ansmission and distribu tion system It usually marks the beginning of electric power distribution It is made up of units that perform very important roles in power distribution and transmission Substations have very powerful transformers that transform voltage from low to high or high to low depending on the requirement at that particular station When power generation starts from the main generating plant it usually flows through more than one substation before finally reaching the final consum ers with its voltage going through series of step ups and step downs via the use of step up and step down transformers respectively Modern day substations are usually unattended to except in some really critical situations they are built in such a way that remote control and supervision can be done via an industrial control system called SCADA Supervisory Control And Data Acquisition running on computers in a control center or centers Substations consist of components such as power transformers switching and protection gear and control equipments A large station usually has circuit break ers used to interrupt the power network in case of a fault which may result to short circuits or current overload Devices such as sophisticated capacitors and voltage regulators can also be found at a power substation Figure 3 Hydroelectric power substation 7 2 12 or Auto Recloser In electric power distribution system a Reclo
33. cent and most dynamic ways of doing things which in my own opinion would make 3G technology even more suitable for this purpose Fourth technologies tend to go smaller smarter and faster in a bid to accommodate further enhancement in the design of devices made by most manufacturing industries Although one could argue that does the size really mat ter since most of the devices that would be using the modem as medium of com munication are in fact really big well the answer to that would be what if the small space it would occupy would lead to a proportional reduction in price of production for the company and would lead to a significant price reduction to the entire budgeted amount of that product to be produced for that year and perhaps the ABB could be planning on producing a BETA version of the circuit breaker and are looking out to make it even more portable and faster Another argument could be wouldn t the reliability and performance of the 3G be stretched to a limit in an area where there are more users of the 3G network than it can support at a time In that case the answer would be that is the reasons why there are usually back up plans in place to guarantee almost 100 safety especially in such an un common situation In all time is quintessentially important especially in data transmission and its importance cannot be overemphasized when it comes to safety and accident avoidance As engineers we are trained to be error conscious an
34. d create an error free system if possible so if going for a technology that will reduce round trip delay time and in which packet loss will be minimal will bring about creating such a system then it s worth giving it a consideration 67 7 REFERENCES 1 Viola systems website Accessed 9 6 2012 http www violasystems com cases monitoring and control remote assets using cellular technology 2 Viola systems website Accessed 9 6 2012 http www violasystems com smart grid smart grid 3 GSM overview website Accessed 10 6 2012 http www tutorialspoint com gsm gsm_overview htm 4 J rlstr m Jarmo 2012 Interview by Afolabi Ibrahim Gao Chao amp Kalevi Ylinen ABB Oy 11 5 Radio electronics website Accessed 14 6 2012 http www radio electronics com info cellulartelecomms gsm technical gsm introduction php 6 Cisco com website Accessed 14 6 2012 http www cisco com en US docs ios 12 2 mw configuration guide mwcfgpov p df 7 SciencePhotos website Accessed 4 7 2012 http www sciencephoto com media 343775 enlarge 8 G amp W electric website Accessed 4 7 2012 http www gwelec com viper solid dielectric three phase reclosers p 96 l en html 9 IAEI magazine website Accessed 4 7 2012 http www iaei org magazine 2008 03 medium voltage inspection basics 10 Satelline official website Accessed 24 9 2012 11 SATEL Oy website SATELLINE 3AS V3 4 UK datasheet Accessed 11 6
35. d demand proper network and supply of electric power has to be in place from the electric energy generation stations to the final user i e the consumers at home in offices and heavy manufacturing industries Achieving this goal without mincing safety and security pose a great challenge to the energy producers From the proper planning of electrical networks to the me ticulous and adequate monitoring and control of various electrical substations and power outlets this is in no way an easy task Transmission of intelligent infor mation other than kilovolts via normal high and low tension cables posed a great difficulty Hence the need to use another means of data communication precisely wireless communication The first solution as used by ABB was a radio frequency modem which turned out not to be able to properly handle the complexity of some electrical networks Then GSM modems were introduced but did not last for too long because they suffer from periodic re establishment of connection and to solve this problem GPRS modems were introduced in 2003 And now am introducing 3G modems to ABB with its numerous benefits and a major focus on the influence of the round trip delay time and packet loss To research the significance of this two factors an emulation program was designed to send and receive data over a 3G modem data samples were taken and analyzed and it was discovered that the factors considered are significantly minimal when compared
36. decimal of address length FFFF 36 4 5 7 Network ID The network ID is a very important concept in message routing feature of the SATELLINE 3AS radio modem It is very useful for security of the network and prevention of unnecessary access to network resources by external devices The network ID is a string of about 8 characters identical to all radio modems operat ing in the same network using Message Routing Messages having different net work ID other than the one generally known by all operating modems coming from external systems are rejected except those with the same network ID 37 47 5 TESTS RESULTS AND ANALYSIS 5 1 Satelline 3AS Radio Modem Tests were carried out using the SATELLINE 3AS radio modem to determine if it actually conforms with all the specifications in terms of functionality as explicated in its user manual and also to see if there are setbacks it suffers from when put to use and possible ways of tackling them To do this a laboratory exercise was con ducted in Technobothnia in the electrical engineering department of VAMK UAS 5 1 11 System Setup The system setup consists of both hardware and software Lists of Hardware SATELLINE 3AS radio modem Desktop computer Oscilloscope RS 232 Bridge connector Tiny copper cables Electric power Recloser Disconnector A complete electric power Recloser controller including ABB rec523 Lists of Software Microsoft Window s operating system
37. e automation control backbone to GPRS and adop tion of the Viola s Arctic IEC 104 Gateway This gateway is an industrial grade serial to GPRS gateway equipped with a built in firewall and VPN technology for secure communication 40 Now is the time for ABB to go 3G Having conducted a thorough research on this possibility with available resources within the scope of this thesis work I am con vinced that if ABB should migrate to 3G it will do them a lot of benefits Benefits which will be described in my conclusions below but first the tests result and analysis of the 3G technology used to simulate the possibility of this migration 5 2 1 System Setup The setup comprises both software and hardware The hardware are 3G modem cat5 cable and two laptop PCs The software on the other hand are windows 7 op erating Microsoft visual studio compiler Ubuntu Linux gedit text editor GNU gcc compiler and a UDP server and client emulation program implemented in C and programming languages respectively The 3G modem used is made by HUAWAI and internet service is provided for it by Saunalahti oy Finland This modem has the following basic features HSPA HSPA UMTS 2100 900 MHz EDGE GPRS GSM 850 900 1800 1900 MHz 21 6 Mbps downlink 5 76 Mbps uplink Micro SD card slot Compatible with Windows XP SP3 Windows Vista and Windows 7 Mac OSX 10 5 and 10 6 5 2 2 Test arrangements In an ideal situation for a successfu
38. e chains may however appear in a serial or parallel format in the same systems Successful transmission of data packet from a source modem to a destination modem in such a robust extended network poses a challenge To solve this challenge routing and addressing of data packet seem to be the only options available to ensure that information will not end up in the loop formed by these repeaters in the network and messages are received by the target ed radio modem 30 39 4 4 2 Addressing Addressing can be used to achieve two main purposes message routing and paral lel network separation It is necessary to use addressing for message routing to prevent data packet from ending up in network loops When the message routing function is set and in use the traditional Rx Tx addresses are ignore not used for transmission by the modem software The radio modem has provision for the use of individual addresses of modem for both transmission and reception of data packet And these addresses can be enabled for both transmitted and received da ta The SATELLINE 3AS radio modem has two transmission and two reception ad dresses for data transmission and reception These addresses are known as the primary and secondary addresses The primary address is used for the transmis sion of data from serial interface and at the receiving end the modem can receive using any of the two available reception addresses The secondary transmission address is
39. ecv seq 1378 rtt 78 181604773 seqno 1379 181604851 recv seq 1379 rtt 78 181605241 seqno 1380 181605319 recv seq 1380 rtt 78 181605709 seqno 1381 181605755 recv seq 1381 rtt 46 181606177 seqno 1382 181606255 recv seq 1382 rtt 78 181606645 seqno 1383 gt gt gt 181606707 recv seq 1383 rtt 46 181607113 seqno 1384 gt gt gt 181607175 recv seq 1384 rtt 46 181607581 seqno 1385 gt gt gt 181607643 recv seq 1385 rtt 46 181608049 seqno 1386 gt gt gt 181608127 recv seq 1386 rtt 78 181608517 seqno 1387 gt gt gt 181608563 recv seq 1387 rtt 46 181608985 seqno 1388 gt gt gt 181609047 recv seq 1388 rtt 62 181609453 seqno 1389 181609921 seqno 1390 181609983 recv seq 1390 rtt 62 181610389 seqno 1391 181610451 recv seq 1391 rtt 46 181610857 seqno 1392 181610903 recv seq 1392 rtt 46 181611325 seqno 1393 181611387 recv seq 1393 rtt 62 181611793 seqno 1394 gt gt gt 181611855 recv seq 1394 rtt 62 181612261 seqno 1395 181612323 recv seq 1395 rtt 46 181612729 seqno 1396 gt gt gt 181612807 recv seq 1396 rtt 78 181613197 seqno 1397 gt gt gt 181613243 recv seq 1397 rtt 46 181613665 seqno 1398 gt gt gt 181613727 recv seq 1398 rtt 46 181614133 seqno 1399 181614195 recv seq 1399 rtt 62 181614601 seqno 1400 181614679 recv seq 1400 rtt 78 181615069 seqno 1401 gt gt gt 181615115 recv seq 1401 rtt 46 181615537 seqno 1402 gt gt gt 181615583 recv seq 1402 rtt 46
40. ficult seem so simple To Makel Jarmo Dr Principal lecturer the most humble and sound minded mathematician and physicist have had the honour of studying under I personally refer to him as Mr Mathematics made easy To Seppo Makkinen Dr Principal lecturer easily approachable someone who can take you on a trip to the land of the greatest physicists and you will never be bored He is a man of practi cality and precision And to a whole lots of other teaching members of staff at VAMK To my doctor though you came later but your impact was immeasurable and to everyone who has been a part of my story both in the past and at present I appre ciate you all and love you so much thank you Ibrahim Adewale Afolabi CONTENTS AKORI ORO ABSTRACT ACKNOWLEDGEMENT NAAT INA KALAKARAN KNA 4 ABBREVIATIONS 9 INTRODUCTION ea 10 1 1 Thesis Outline n eet eed earned 10 2 ELECTRICAL POWER DISTRIBUTION NETWORK A 11 21 Description of Each Power Grid 14 2 1 1 Power Substation 14 2 1 2 Recloser or Auto Recloser ioi e e 15 2 1 3 DISCOHDECLOE 16 2 1 4 Distribution Transformer notio 17 2 1 5 Ring Main Unit RIM
41. frequency due to the availability of a device working on its backbone protocols This device is one of the numerous devices in use and in the fore front of wireless communication in electrical networks today in Finland The SATELLINE 3AS radio data modem A comparison between this device and the possibility of using a 3G based network system to achieve similar task will be made in a later chapter 41 Satelline Radio Modem SATELLINE 3AS To be investigated in this project is the Satelline 3AS d radio data modem La Figure 7 Satelline 3AS radio modem 10 boratory exercise would be carried out on it to properly determine how it truly functions and test its limits To achieve this I shall use the one already in use in the electrical department of VAMK University of applied science present in the Technobothnia research laboratory Vaasa But before I go further a brief tech nical specification would be very helpful in the introduction to the radio modem 27 411 Satelline 3AS d Technical Specifications Satelline 3AS 3AS d radio modem is a wireless radio frequency modem with RS 232 RS 422 and RS 485 interfaces Satelline 3AS d as the name implies is a modem with an LCD display with four push buttons and ordinary Satelline 3 AS is without a these features The device is capable of frame error correction and has repeater and free channel scanning functions The 3 AS d shows messages on dis play and both are compat
42. he client and server programs to emulate the polling functionality of the Satel systems at a frequency of about 2 2Hz as described above data were collected of the RTTs of each of the packets sent and received over a 3G modem for every approximately 1400 packets sent at a run of the program packets losses were also calculated and the average RTT for the entire received packets was also taken into consideration Below is the figure showing the beginning and the end of one of the outputs of the program saved in a text file start time 180959365 180959365 seqno 0 gt gt gt 180959412 recv seq 0 rtt 31 180959833 seqno 1 gt gt gt 180959880 recv seq 1 rtt 47 180960301 seqno 2 gt gt gt 180960348 recv seq 2 rtt 47 180960769 seqno 3 gt gt gt 180960816 recv seq 3 rtt 47 180961237 seqno 4 180961284 recv seq 4 rtt 47 180961705 seqno 5 180961768 recv seq 5 rtt 47 180962173 seqno 6 gt gt gt 180962236 recv seq 6 rtt 47 180962641 seqno 7 180962688 recv seq 7 rtt 47 180963109 seqno 8 180963187 recv seq 8 rtt 63 180963577 seqno 9 180963640 recv seq 9 rtt 63 180964045 seqno 10 gt gt gt 180964108 recv seq 10 rtt 63 180964513 seqno 11 180964576 recv seq 11 rtt 63 180964981 seqno 12 gt gt gt 180965059 recv seq 12 rtt 78 180965449 seqno 13 180965496 recv seq 13 rtt 47 180965917 seqno 14 180965980 recv seq 14 rtt 63 180966385 seqno 15 180966448 recv seq 15 rtt 63 180966853 seqno
43. iagrammatic representation of this modern system and method of electrical power networks and distribution is shown in Figures 1 and 2 below first is a fig ure that shows a literal image of such network distribution and then second a more technical figure The images are the Viola system s comprehensive range of de vices for automating and monitoring various elements found in different stages of electrical power distribution networks and smart grid technology implementation 1 Nena Control Centre Figure 1 Power distribution network from Power generation to Metering 1 13 Distribution Viola M2M Gateway CUSTOMER APPLICATIONS Billing Distribution Automation Energy Audit Figure 2 Technical description of electrical power network wireless monitoring 2 The Figures above depicts what a typical modern day electrical power distribution network looks or should look like Where wireless communication network are made an intrinsic part of the electrical network planning and configuration and implementation phase Each part of the power distribution section having its own appropriate wireless communication and data transmission device Starting from the Substation to the Recloser to the Disconnector and then to the Metering part of the entire distribution network 21 Description of Each Power Grid 2 11 Power Substation This is a fundamental part of electric power generation tr
44. ible with Satelline 3 AS Epic and modems The Satelline 3AS d complies with the following international standards specifications RADIO TRANSCIEVER Frequency range 330 470 MHz Tuning range 2MHz from central frequency Channel spacing 12 5kHz 20kHz 25kHz Number of channels 320 200 160 2 x 160 100 80 Frequency stability lt 1 5kHz Type of emission FID Communication mode Half Duplex RADIO TRANSMITTER Carrier Power 10mW 1W 50ohm Carrier power stability 2dB 3dB Adjacent Channel Power According to EN 300 220 I EN 300 113 1 Spurious Radiation According to EN 300 220 I EN 300 113 1 RADIO RECEIVER Sensitivity 115 110dBm BER lt 10 E 3 Common Channel Rejection gt 12dB Adjacent Channel Selectivity gt 60 dB O 12 5kHz gt 704 O 25kHz Intermodulation Attenuation 65dB Spurious Radiation 2nW MODEM Interface RS 232 or RS 485 RS 422 Interface Connector D15 female Data Speed of Serial interface 300 38400bps Data Speed of Radio interface 19200 bps 25kHz 9600 O 12 5 20kHz Data format Asynchronous RS 232 or RS 422 or RS 485 29 Operating Voltage 9 30Vdc Power Consumption 1 1 W Rx 5W Tx 0 05W in standby Mode
45. ideo calls teleconferencing wireless voice telephony tethering and fixed wire less internet access For applications to operate using 3G wireless technologies they have to be devel oped and function in accordance with the set system specifications of the IMT 2000 based on the reliability and the data transfer speed of the entire system This speed should be at least 200kbits or 0 2Mbits per second However most 3G ser vices provide data speed higher than this minimum peak data rate Some known 3G technologies are the UMTS system which was standardized by 3GPP This technology is commonly used in Europe Japan china and other re gions where GSM second generation system is widely in use today The UMTS original release is called W CDMA and then followed by the TD SCDMA and the latest release 15 HSPA which is capable of data transfer of about 28Mbits per second of downlink transfer of packet and 22Mbits per second of uplink practical ly The other 3G technology is one which is common in the North America and also South Korea Is the CDMA2000 system which was standardized in 2002 by 3GPP2 It shares infrastructure with the American 15 95 2G standard Hence most cell phones operating in the system are capable of functioning with the CDMA2000 and IS 95 hybrids Its latest development is the EVDO which is ca pable of peak rates of about 14 7Mbits per second downlink 3 4 Normal Radio Modem Radio frequency modems have the capability
46. ii le gbo isoro idijulolu awon eka itan ina leyin naa ni atun se afihan awon Modeemu telifoonu agbeka ti amo si GSM amo won ko pe rara nitori won maa n dakudaji lati le bori isoro yii ise afihan ero GPRS modem waye ni odun edeegbewa le meta Nibayi mo n se afihan 3G modem fun ABB ati awon anfaani ti orogbayiika pelu idojuko pataki si asiko idaduro ajo rogodo ati ipadanu eru se agbeyewo pataki awon ohun mejeeji ani lati se progiramu ti alefi koko gbiyanju isisee re wo na nibi isoro ngbesi tin lo 3G modem ase iyannana awon esi ti ari latara igbeyewo ti afi progiramu se asi ri wipe mo ni iwonba legbe awon tekinologi ateyinwa julo Radio frequency modem Nigbeyin alefi gbogbo enu so wipe fifi 3G modem tekinologi ateyinwa fun ise amojuto eka itanna yio je ohun ti koni mu ewu wa rara Koko inu oro ibolowo ewu RF modeemu GSM GPRS 3G Ifi ohun aifojuri ranse ABB VAASAN AMMATTIKORKEAKOULU UNIVERSITY OF APPLIED SCIENCES Degree Program of Information Technology ABSTRACT Author Ibrahim Afolabi Title Consideration of using 3G cellular network to monitor ABB s remote circuit breakers Year 2012 Language English Pages 75 Name of Supervisor Chao Gao Increase in the energy demand for domestic purposes as well as in the manufactur ing industries has led to a rapid and proportional increase in the electrical energy production today In meeting this huge electric consumption an
47. imal atten tion is paid to efficient distribution of power safety of life and property after in stallations especially in times of emergencies which could arise from any man made or natural disaster inefficient management and detection of power outages improper planning of electrical power network and distribution etc 11 Thesis Outline To successfully discuss the objectives of this thesis as mentioned in the last sen tence of paragraph one the following has to be looked into in subsequent chap ters modern day power distribution networks wireless technologies available and in use for remote control and monitor ing of electrical power distributions general introduction of the radio frequency modem tests and analysis of results and conclusions and possible recommendations suggested 11 2 ELECTRICAL POWER DISTRIBUTION NETWORK In the past few decades safety and security of life is no longer a thing of option instead it has been made strictly part of every decision made during the implemen tation phase of most if not all projects that has to do with electric power and in stallations Especially in most developed world and this same system is gradually and rapidly spreading across the developing worlds In fact in a way to standard ize this new practice standard bodies are being put in place to make sure all the rules and protocols to ensuring that all stipulated standards are followed to the lat ter A d
48. ion using a broadcast address in multiple point to point configurations 38 From Figure 11 above a capture of packets of transmitted and received data was taken for REQUEST RESPOND data transmission from oscilloscope s channels one and two respectively From the cursors markers X1 and X2 it can be ob served that there is a response transmission delay of 60ms Back to Figure 9 above the request signal is transmitted with a frequency of 2 174Hz at a transmission delay of about 450ms which can be clearly seen in the Figure that follows it immediately through the cursor markers X1 and X2 Sub tracting the value of from X2 will give the corresponding time interval be tween two data packet transmission That is if TX is the approximate time interval between transmission of two data packets then we have 2 839 000ms 390 000ms 449 000ms Similarly if tx is the transmission delay between a REQUEST and RESPOND just as in Figure 11 above then we have Atx X1 X2 0 0000ms 60 0000ms 60 0000ms Conversely in figure 11 Atx is calculated using X1 X2 because the normal conventional way of X2 was not taken into account during the measurement and as such made the X2 cursor come before the X1 But the round trip time nor mally should be measured just after sending a packet and receiving a response So to do this markers in red colour are made at that position for both sent
49. ions Consequently the controlled stations respond by sending bits of infor mation back to the controlling station which will be analyzed and interpreted be fore necessary action s will be taken The most important thing to note in this type of transmission is that communication can only be initiated by the controlling station and it done by polling There are three main transmission services support ed by the unbalanced transmission They are SEND NO REPLY SEND CONFIRM and REQUEST RESPOND When a SEND NO REPLY type of service is transmitted to the controlled station it is issued to broadcast a global message and set some commands on the controlling station SEND CONFIRM service is used to transmit control commands and set point commands to the con trolled stations and the REQUEST RESPOND is used for polling data from the controlled stations 38 In balanced transmission on the other hand information and data transmission can be initiated by either the controlling or controlled station And they can both act simultaneously swapping responsibilities as a result they are called combined sta tions In the balanced transmission procedure information transfer can only occur in point to point and multiple point to point configurations The balanced trans mission procedures are also capable of SEND NO REPLY and SEND CONFIRM transmission services However in SEND NO REPLY service transmission can 53 only be initiated by the controlling stat
50. ir If a modem is cur rently transmitting data the transmitted data will be temporarily buffered until the reception has stopped before transmitting the buffered data 20 33 Apart from the features discussed above Satelline Modems have additional fea tures such as Error correction Error checking Free channel scan Dual channel function Dual band function LED indicators as well as LCD display and push buttons in the SATELLINE 3AS d 4 3 Transparent Data Transmission 4 3 Serial interface and data format The SATELLINE 3AS radio modem uses an asynchronous data format to trans mit data through the serial interface without using any external synchronizing sig nal This is so because relevant timing information defined in the start and stop bits transmitted before and after each data field bits which marks the end and start of data transmission The data transfer speed of the serial interface varies from 300 600 1200 2400 4800 9600 19200 to 38400 bps The length of the data field can only be any of 7 8 or 9 bits The use of data field length of 7 or 8 makes space for a parity bit So to transmit one character we will need a start bit the data bits which is the binary representation of the character to be transmitted an optional but useful parity bit and one or two stop bits making the total length of the transmitted data bits to be 10 11 or 12bits When calculating the data throughput of a system the number of s
51. l authorities It is highly encouraged to set the output power of the transmitter to the lowest possible that can still allow error or inter ference free connections under severe conditions and this is because using a very strong signal to strength for short range connection could hamper the over opera tion of the entire system 4 2 2 Receiver When used as a receiver its sensitivity depends on the spacing of the channels on which the radio modem is operating and the mode of its error correction The threshold of the receiver s sensitivity determines a level just above which data transfer signal can be detected and active 4 2 3 Priority RX TX Part of the features offered by the SATELLINE 3AS is priority setting This func tion selects the priority between reception and transmission It is a function which can either be enabled or disabled from the Programming Mode But the default setting is in terms of priority is transmission TX first and then followed by recep tion Priority TX as a setting means that a terminal device connected to the modem chooses the timing of the transmission As soon as the terminal device is power on the transmitter will be switch on instantly if reception is the priority at that point in time it would be stopped and changed to operate in a state of transmis sion Priority RX as a setting means that a modem is in the receive mode is trying to receive data currently available and in transmission in the a
52. l communication to take place between two devices message exchanged has to be timely and complete To be investigated in this section is the RTT the time taken to send a packet to a remote host and receive a reply from it of individual packets sent and received over a network modeling a laptop PC as the remote substation equipment and an other laptop PC as the control center super computer sending packets and receiv ing responses from the remotely located PC As a medium of communication for the remotely located PC say node A is using an ADLS WAN connection with Saunalahti as the ISP and the second PC in the control room is using the HUAWAI E367 3G modem as the medium of communication Since we are mod eling this system against the SATELLINE 3AS radio modem as used early in the years by ABB and explained above it was necessary to develop a system that would perform similar tasks in subjected to similar if not exactly the same condi tions Perhaps a quick recall of how the SATELLINE system works will do In the Satel system there are two 2 nodes namely A and B Node A at the substa tion is remotely located on the open field while node B is somewhere near in the control room Node B polls A at a frequency of about 2 2Hz And if node A re ceives the message it sends a reply back to node B From this poll and reply mes 57 sages a round trip delay time be calculated And if any reply comes back to node B with a sequence n
53. learly seen in the Fig ure 17 above However comparatively if the time taken for a packet to be sent through SATELLINE 3AS radio modem and receive a response in approximately 58 33ms as in Figure 11 above with an approximate distance of less than 3meters apart distance between the SATEL radio modems in Technobothnia it will be safe to say if all the above factors affecting the RTT delay are kept constant except the physical distance and data transfer speed between source and destination wireless modem it is apparent without any calculations that using a 3G modem with simi lar data transfer rate as in the HUAWAT s in this simulation test will give an RTT far less than the AVE RTT 67ms in Table 10 above And the presence of several Satel modem forming terminals in a network would significantly increase the RTT if messages were to be exchange between the nearest and the farthest of the terminals Figure 18 above shows the RTT frequency distribution histogram for a batch of the set of packets sent over the 3G network It is quite amazing to see such result as up to 566 packets was sent and received only after 47ms in flight It should be noted that one of the major factors affect the RTT of a packet which is the amount of processed handled by the intermediate nodes and destination computer could have played a significant role in the set of data collected because the set of com puters used are not just dedicated to the processes run
54. locked a steel house and in other cases such as those found in some developing countries which are left naked on the concrete pad on the street they are known as pad mounted transformers And usually they are made to transmit voltages below 30kV especially those mounted on the pole due to the weight restriction Distribution transformers are normally located at distances where it is quite easy to run electric cables from electric power pole or underground power lines to a customer s facilities They are used for power supply to consumer s facilities such as farmyards pumping stations large high rise buildings etc where power is pro vided at voltages under 30kV They could be single phase transformers like those generally used in the USA power distribution system and could be three phase transformers like those used in the European power system where three second ary windings are attached to the three primary phase wires to provide power for residential services Figure 6 A pole mounted Distribution Transformer 9 19 2 1 5 Ring Main Unit RMU Ring main unit is a part of the electric power distribution network which is usually a standard piece of switchgear comprising of switches for switching rings of low voltage power cables and also for switches connected in series with fuses for the purpose of protecting distribution transformers from direct impact of faults on the power distribution network It is a secondary b
55. ning on both computers for the simulation at the time when it was done unlike that of the SATELLINE 3AS modems It has to also be pointed out that the duration of time the Satel device was made to work as regards the laboratory exercise done with it was not so long to show pos sible lack of reply to polls from the control room RF modem which would have been really nice to show how unstable it could function sometimes 65 6 CONCLUSIONS AND RECOMMENDATIONS After a successful conduction of laboratory exercises and series of tests and simu lations an extensive look was taken into the functioning of the SATELLINE 3AS radio modem and it can be said that it is good at what it is designed to do within its capacity however handling the robust demand of the task it was put to by ABB would have been just too much for it Time is life when it comes to electric power generation and network monitoring every fraction of a second counts Timely delivery of intelligent data over a wire less network for monitoring purpose has to be almost certain for accidents to be avoided and disasters to be averted Timing and reliability of transmission medi um would have been part of the reasons why ABB collaborated with Viola sys tems to be provided with a system whose main infrastructure is GPRS But having conducted a thorough research on the probability of using a 3G technology via the use of a 3G modem and the UDP datagram emulation program simulating the
56. on network And power can be temporarily restored to the isolated area through other forms of power generation available at that particular point in time e g wind mill generated power They are not aimed at providing a normal day to day control functions on the power circuit they act basically as isolators Disconnectors are called to use 17 whenever field maintenance is required on any of the network sites They can be operated both manually and remotely and for this reason there is provision for padlocks so that when field engineers are working to fix a problem on a site after electricity has been put off accidents resulting from inadvertent operation to re store power back to the site through remote control or an unconcerned individual engineer could be absolutely prevented and avoided So the Disconnector is for ensuring absolute safety on the power distribution network Figure 5 old pole mounted Disconnector 9 2 1 4 Distribution Transformer In power distribution network a distribution transformer is a transformer that does a high to low voltage transformation of voltage It provides power to the final consumers at a stepped down level that suits the need of the customers They are of two main types based on where they are installed If installed on a pole they are referred to as a pole mounted transformer and if they are found in stalled on the ground level mounted a concrete pad in most cases
57. ranch of the power distribution network system Basically it ensures uninterrupted flow of power and protection of the secondary side distribu tion transformer from periodic transient currents and it limits the effects of faults on the network It usually comes in a complete protection house made of alloys and consists of switch disconnectors earthing switch fuse switch or circuit breakers and other protection units that make up a complete functional ring main unit In Finland for example the Reclosers and the Disconnectors are made together as one unit and are otherwise and sometimes called Isolator in the U S A Moving from the Substation to the Metering the amount of Voltages transmitted through the cables reduces from about 400kilovolts to about 400volts which finally gets to the final consumers and further stepped down to the required amount of about 240 to 230volts for basic home appliances They all function in a well coordinated way via the functionality provided for by the MicroScada software running on a computer in a control room They work in such a way that the respective modems running on either of the available wireless technologies as a means of communication backbone would send and receive in formation to and from a control room The control room has software applications for example the ABB MicroScada pro running on computers in the control room that coordinate monitor control and poll information from these various and re
58. rt of data transfer a synchronization signal will be sent to any nearby radio modem present in the network This signal will be detected and its purpose is to inform that second radio modem to prepare itself for data reception On receiving this signal the radio modem switches into data reception mode however it does not happen that fast During the detection and reception of this synchronization signal the initiating radio modem will continue sending data signal just as soon as it completed synchronization signal transmission All the data received during this time will be stored in the buffer memory At the end of every transmission a pause will be detected in the data transmitted by the terminal device and by this time all buffered data would have been transmitted The success of the synchro nization is very important to the proper functioning of the system in that way it makes the both the serial and radio interface transmit and receive signals at the same time But it is still considered safe if the speed of the serial interface is slower than that of the radio interface because it will not cause the internal buffer memory to overflow but if it happens in the other way round overflow of the buffer memory will occur Since the maximum size of the transmit buffer memory is small 1kB it is essential for the terminal device to monitor the status of the 37 CTS line of the radio modem and not to transmit too much data else the buffer
59. s infact the least number of packets loss recorded in the entire 10 program tests Similarly the simulation also shows that the number of packets lost experienced while in flight during transmission is independent of the round trip delay time While the lowest average round trip delay time was recorded in line 7 with an average packet loss of only 2 packets the highest of approximately 74ms was recorded Just below it with an average packet loss of 8 packets Apart from the physical distance travelled by each packets i e from Espoo to Turku with an approximate distance of 150 5 km other factors which may affect the RTT of the packets and or could lead to packet losses are Nature of the medium of transmission e g optical fiber copper and wire less Transmission speed of the source s internet connection Number of nodes present between the source and destination Amount of processes being handled by any intermediate nodes and the destination computer at any point in time How much traffic is experienced on the LAN of the destination computer i e if it operates ina LAN Transmission speed between intermediate nodes and destination computer And perhaps the presence of interference in the circuit If all these factors put together are considered these will explain the random be havior of the AVE RTT when compared to the packet losses and similarly to that of the number of packet sent And this irregularity can be c
60. secu rity or and reasons best known to ABB 39 And all effort to get reasonable in formation on this from ABB proved abortive 5 22 3G Based Technology As discussed earlier in this document in chapter 1 above the possibility of adopt ing a 3G based technology to accomplish the same tasks as the medium of infor mation transfer just as the SATELLINE 3AS modem was used by ABB will be 55 investigated and thoroughly researched Presently no longer use SATELLINE radio modem as information carrier between their control stations and substations for client projects but it used to be an intrinsic part of their elec trical system conveying pieces of information from control stations to substations and vice versa In early 2005 ABB successfully changed the medium for its remote controlled automation system for electrical distribution networks from GSM to GPRS as the case may be due to the radical price drop in GPRS technology and the provision of an always on remote data connection A major decision making factor is the fact that GPRS provides them with an always on connection which saves them the stress of having to re establish connection when needed with their formal GSM modem To establish a new connection it takes them an average delay of about 30 seconds which was a significant amount time when it comes to electrical power management ABB collaboration with Viola which however started since 2003 led to the migration of ABB remot
61. ser also known as auto Recloser is a momentary circuit breaker which has a mechanism that can automatically close a circuit breaker after it has been opened due to a fault Recloser are installed on overhead power distribution systems to detect and interrupt faults and then re store power to the distribution line after the momentary fault has been fixed In a bid to improve power distribution quality and enhance safety of life and pow er equipments substations along a distribution network are protected with in stalled circuit breakers or fuses which are capable of turning off power in the event of fault detection such as short circuit Basically Reclosers are located at intervals in network where it is possible to divide the electric power network into smaller sections or grids in a way that it will be possible to utilize less power to trip off only the section it is responsible for in events of fault detection Figure 4 Pole mounted Recloser 8 2 1 3 Disconnector Disconnectors which are otherwise known as Isolators are used in electrical power distribution to ensure total disconnection or cut off of power from electrical power circuit in a situation of fault fixing and maintenance purpose In situations where there is need for adjustment or repair of apparatus such as circuit breakers and transformers and transmission lines high voltage Isolator switches usually comes in handy which enable a total isolation of the remaining distributi
62. tached to the Recloser Disconnector in the laboratory otherwise called the controlled outstation The first image from the results image 9 above however shows detailed characteristics and description of the transmitted Tx signal as described in 60870 5 101 protocol manual This protocol is the set of protocol stack upon which the remote communication device rec523 of ABB was built This communication device is the main backbone of the remote controlled station monitoring the activities going on in the controlled station It is configured such that all the power voltage carrying cables to be monitored are mapped to address es on the rec523 device Events happening on this power cables are then transmit ted to their respective addresses as at when happening from time to time These set of events are the information transmitted to the controlling station in the con trol center as at when polled SATELLINE 3AS radio modem provides the link between the controlling station and the controlled station for information transfer Two major types of transmission can be carried out as described in 23 60870 5 101 protocol manual They are unbalanced and balanced transmissions In the case of unbalanced the data transmission can only be controlled by the con trolling station through polling The controlling station polls from time to time at a particular interval of time requesting for latest information from the controlled stat
63. tart stop and parity bits must also be considered for proper calculation to be attained A very useful rule however is that to transmit one character with a data speed of 9600 bps it will take roughly one millisecond 1ms So for example to transmit 187 as an eight character data bits with a binary rep resentation of 10111011 in the three possible ways described above we will have the following results presented in the table below DATA FORMAT CHARACTER CHARACTER LENGTH 8 bits no parity 1 stop bit 0101110111 10 bits 8 bits even parity 1 stop 01011101101 11 bits bit 8 bits odd parity 1 stop 01011101111 11 bits bit 8 bits no parity 2 stop bit 01011101111 11 bits 8 bits even parity 2 stop 010111011011 12 bits bit 8 bits odd parity 2 stop 010111011111 12 bits bit Table 3 Data format example It should however be noted that if data speed settings length of character parity or the number of stop bits differ between the communicating radio modems and the terminals errors are bound to set in into the transferred data If the serial port settings of the radio modems exchanging data in the system are different there is no problem but the data length settings must always remain the same in all indi vidual communicating radio modems In clear and simple terms the serial ports used for transmission the speed of data transmission the parity and n
64. tation The terminals are mostly PLC devices capable of sending and receiving messages according to a well defined user protocol 33 4 5 1 Message Routing features The aim of creating the message routing feature of the SATELLINE 3AS and 1 radio modem is to design a fast and transparent system that can fit real time sys tems as much as possible These features include Transparent to user protocols Easy construction of a network containing several repeaters Any radio modem can operate as a repeater thereby negating the need for special repeaters which in turn reduces price One radio channel is enough to cover large areas through its use Using mobile station is also achievable The principle of Message Routing is made to be connectionless in that the transmission delays are made predictable making it a fully deterministic sys tem Added redundancy Message Routing is used mainly for protocols designed based on polling principle and a single Base or Master station is needed 34 4 5 2 Message Routing Limitations It is readily assumed that the position of the address field in the user mes sages is fixed Even though special protocols such as 60870 5 101 and 570 protocols which are used to control applications of power lines supported it does not mean the system supports all available protocols There must be at least one character after the address since it is not designed
65. to suit serial data transfer espe cially in situations where the distance between communicating devices is less than 15meters 14 42 RF Interface This model of Satelline used in this project i e the Satelline 3AS radio modem has a single TNC type connector with a total impedance of 50 Ohms Usually the frequency range to which the device will be tuned is defined at the point of order and it can be changed afterwards by 2MHz from the centre frequency Bearing in mind that all local regulations set by destination authorities has to be considered and conformed with The speed of the radio interface depends on the chosen radio channel spacing which could be either 19200bps or 9600bps If a spacing of 25 kHz is chosen a total of up to 19200 bits of data can be transferred through the channel in one se cond and if lower than that is chosen e g 12kHz only 9600 bits can be sent through the channel and regardless of the chosen channel spacing the data speed limit is fixed already at either 19200 or 9600 bps What happens in a situation where the data speed of the radio interface is more than that of the serial interface is that the data in transfer would be buffered temporarily so there would not be any data loss in any case 17 4 21 Transmitter The radio modem be used as both a transmitter and receiver When used as transmitter the output power can be varied of which the greatest allowable power would be decided by the loca
66. to the rest of the previous technologies especially the radio frequency modem And it can be safely concluded that the 3G modem can be used to replace any of the previous technologies for the purpose of monitoring the electrical power distribution network Keywords Safety RF modems GSM GPRS 3G Transmission ABB ACKNOWLEDGEMENT To Allah azza wajal God the Almighty who made me who I am today and will make me what I hope to become tomorrow To my mother who instilled in me the never say die spirit and is everything to me She taught me to give and never look back share and never expect she is an exemplary giver to whom this final thesis is dedicated To my father a man of honour and integrity the best one can have He taught me discipline diligence fairness patience modesty humility and respect for others and their rights To my siblings who have been supportive of my decisions in life and have always being there for me To friends my brothers and sisters from another mother who have been a source of motivation and have inspired me enormously To Gao Chao Dr my supervisor an esteemed instructor of high standards a teacher of quality and ethics a man of dignity and respect someone I owe a lot to for his tremendous support in the cause of this thesis and my study at VAMK Liu Yang Dr the challenger who would squeeze the best out of you To Johan Dams the greatest motivator have ever met makes the most dif
67. ts the message received from the terminal device e g the open field Recloser Disconnector Ay Pk Pk 11 9V 1 2 174Hz Recall Default Quick Print m Setup Save Figure 9 TX data signal capture a a 2 1 4 O 05 0 gt 1 lt gt 2 390 000ms 839 000ms 1 2 Figure 10 Data packet transmission delay zoomed in 5 E E X1 Hex 1 4 4 D D 2 1 4 4 05 0 gt Mode gt Source lt Xl lt D 2 015 0 0 05 60 0000ms Figure 11 TX and RX data signal capture Current i Std Dev 423 Source gt Select Measure ngs ETT Meas al istics Freq Freq Figure 12 TX RX Poll and Reply sequence 51 Freq Figure 13 Transmitted request data format 5 14 Result Analysis Figure 9 above is the first capture taken from the oscilloscope used for the meas urement of the signal transmitted from the Tx pin of the RS 232 serial interface connector of the central computer in the control room otherwise known as the controlling station In that figure and subsequent ones it can be clearly seen that polling messages are sent at regular interval to the radio modem which would normally be on the field but in this case at
68. umber of stop bits can be different in different parts of the same system with no risks of errors in the transmitted set of data This is a very useful point to know especially in systems where one part uses an RS 232 serial port and the other part uses RS 422 serial port 26 35 4 3 2 Handshake lines Handshakes can be used to control data transfer when using RS 232 serial inter face Handshake is very useful in that it informs the terminal it readiness to initiate transmission and notifies it when busy and free to transmit The terminal can also issue control functions to the radio modems through RTS line The table below shows list of LED line indicators and direction of commands Line Direction CTS To terminal RTS To modem CD To terminal Table 4 Handshake lines 27 Basically handshaking is used in systems with complex protocol and huge data transmission to prevent regular data collision System with simple enough proto col like data polling as it is in my own case handshaking is not needed The easi est and most effective way to implement handshaking in this case is to monitor the CTS line only 27 4 3 3 Possible delays and timing during data transmission To be discussed are delays encountered in the course of data transmission and re ception and how data are buffered in the radio modem and how the modem marks the end of transmission with a parameter known as pause length Delays
69. umber out of order or the reply did not come at all packet loss can be counted from it In a nutshell node A is working as a server always waiting for the polling messages and B works as a client initiating com munication and sending polling messages Similarly and to emulate this system a client and server program was designed to be run on each laptop PC as described above the server program runs on node A and client program on node B The client program running on node B was de signed to send dummy data to node at the same frequency as Satels 2 2Hz ap proximately 0 455sec and get reply as soon as possible from node regardless of whether a reply comes of not node B will always send the dummy data to node A which is always listening from a remote location at every 0 455 sec 2 2 2 in terval The client program runs on my laptop node B on AALTO campus in Es poo implemented in C programming language and developed on Microsoft visual studios the server program on the other hand runs on a friend s computer node A in Varissuo in Turku implemented using C programming language and developed using a simple text editor installed on Ubuntu Linux and compiled with GNU GCC compiler The unique blend of intercommunication of applications de veloped in different programming languages is one of the awesome concepts and unlimited diversity of Information Technology 5 2 3 Test Results After a successful design and compilation of t
70. y and prevent eavesdropping 5 3 20 GPRS Technology Overview GPRS is a 2 5 digital generation system It is a relatively new service designed for Global System for Mobile Communications GSM networks GSM is a digital cellular technology that is used worldwide predominantly in Europe and Asia with current estimates of 400 million subscribers and growing GSM is the world s leading standard in digital wireless communications 6 GPRS is standardized by the ETSI GPRS is a packet based radio data mobile technology created to fit in between the 2G and 3G cellular communication tech nology It is a packet oriented technology whose usage is charged based of vol umes of data sent and received Contrary to the GSM circuit switching data tech nology charged per minute of established connection time irrespective of whether data transmission took place or not 3 3 3G Technology Overview The word 3G stands for 3 Generation It is a common terminology otherwise used for the 3rd generation of mobile telecommunication technology It is made up of a set of standards which are used for mobile devices and telecommunication services including networks that adhere to the standards of the International Mo bile Telecommunications 2000 IMT 2000 engineered by the International Tele communication Union When talking of 3G to a lay man it is best explained as all those application in wireless data transmission that support mobile internet access v

VAASAN AMMATTIKORKEAKOULU

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