automation systems in pow er utilities

7/28/2019 Automation Systems in Pow er Utilities

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The Developmentof an Intelligent& IntegratedGateway SystemfortheAutomation Systems inPowerUtilitiesM S. K im and D.H. Hyun,Researcher,kZPRI

Abstraci-In recent years, it has been a worldwide trend thatmany power utilities gave their attention to deveop and operatetheir power plants, substation and distribution systems. Followingthis trend, KEPCO(Korea Electric Power Corporation) hasdeveoped many electric automation systems with variouscommunication networks. It has been natural that the automationsystems are just focused on to remote devices when they cometobe designed. But, we have to shift the focus to the automationsystemitsef.There are many problems in maintenance and integration ofthe automation systems. When an automation system cantcontrol some remote devices, there is no way to get why andwhich part(Master, Network, Master-side Modemor Remote-sidemodem, Remote Device, etc.) of the system has problems.Moreover, the system just directly links to another automationsystem If the system has to link many systems, it needs the linkerper each systems. So, we need a new concept to resolve thatproblems, and deveop the Intelligent and IntegratedGateway(1IG) for the automation systems for easy mantenanceand integration.Index Term-Automation Systems, Communication NetworkIntelligent& Integrated Gateway, KEPCO, Power Utility

I . INTRODUCTIONA utomation Systems in Korea include DistributionAutomation System, Automated Meter Reading System,Load Control Systemand Substation Automation System, etc.andmany other systems are expected to be developed.Each automation system has a unique characteristic and isapplied on the various communication network. The mostpopular communication network is the leased communicationline. But, these days, it slowly changes to wirelesscommunication network due to its high-leased fee anddificulty of maintenance [1][2]. Automation systems havedifferent requirements for networks according to theirfunctions. Most automation systems are operatedindependently using the dedicated communication networksleading to duplication.Thenew requirementsof a deregulated utility market can beassumed that the focus of the utilities will be increasinglytowards networked systems. The networked systems are muchM yongsoo Kim and Duckhwa Hyun are with Korea Electric PowerResearch Institute, Taejeon,305-380,Korea (email: [email protected]).

0-7803-7525-4/02/$17.0002002 IEEE.

more far-reaching than those of a typical of ice environmentespecially with respect to reliability, operation andmaintenance of the different types of applications within thesame network. Automation systems are being increasinglyoperatedas distributed systems from the point of view of theapplications[3].KEPRI(Korea Electric Power Research Institute), theresearch center of KEPCO, already developed and operatedthe Front End Processor with Media Dependent Interface. Itwas well operated with various communication media butmaintenance and expansion were very difficult. Thus, we havedesigned and developed the IIG which supports easymaintenance and integration with multi-communication media,multi-link, multi-service and multi-function.The important elements of designing automation systemshave been mainly the remote automation devices such asswitches and circuit breakers. Improving the functionof thedevices is important for the automation systems. But, thefunctional quality of the devices becomes stable in performngthe automatic operation. The communication devices havebeen the causes of most troubles in an automation system.Therefore, we have to shiftour focus to the automation systemitself.

The communication stability is an important factor of thesystem availability. There isno way to get the informationofthe remote devices when communication is failed. So, it ismost important to keep the communication devices work.Reliable automation systems have to have a new structure toovercome the communication problems. In this paper, weshow new architecture of intelligent and integrated gateway forautomation systems.

11. THE ENERAL CONFIGURATIONOFAUTOMATIONSYSTEMSIn Korea, a Distribution Automation System(DAS) has beeninstalled and operated by most of branch ofEces(l75 out of184). Well explain the IIG in the DAS. From1984, KEPCOhas installed and operated DAS with several communication

networks such as twisted pair cable, coaxial cable, wirelessdata channel etc. Nowadays, optical communication, trunkedradio system (TRS), leased line and wireless datacommunication, are typical communication networks.Introducing DAS into power distribution network reduces

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the power failure recovery time from40 mnutes to2 mnutes.Thus KEPCO plans extending DAS to all the distributionoffices [4]. DAS iscomposed of many devices suchas router,termnal server, network, modem, etc. If one of the devicesdoes not work, DAS does not work properly. So, eachcomponent is important to monitor and control the remotedevices. Fig. 1 describes he configurationofa typical DAS inKorea.

Can tfind where the problem isIt is very difficult to find where the problem is in theautomation systems, because the components of theautomation system dont send any information of the problem.Can tfind how to recover the problem

Even if the automation systems exactly know the problem,they cant fi x the problem because they havent routine forrecovery.

Fig. I . Theconfigurationofgeneral A utomation SystemThe main functions of the Master are monitoring andcontrolling remote devices. The master doesnt support therecognitionor recovery of anycommunication failures. Whenthe master cant reach the specific remote device, it justdisplays communication error and does nothing.In the configuration of the typical DAS, a hub simply

provides electric connection between the master and otherdevices. It cant provide any information about ports, trafficvolume, operating status. So we call it the dummy hub.The termnal server isused with the public lease line. Itsupports checking and changing the status of ports by directconnectionwithPC in local site. But, it is inefficient.The router is connected to the wireless communicationserverand works89thesame way of the termnal server.The modem, installed in remote site, doesnt build in thelooptest function. When the response cant return back, thereisnoway to findwhy and where the problems happen.111. THE PROBLEMOF AUTOMATIONSYSTEMS

A. When theydoesnt work properlyCan t ind why the problem happensThe availability of DAS in Korea is 95%. The automationsystems cant control up to5% of the remote devices and cantclassify the problems.

B. When they add new servicesWhen they t ry to add new services, t is impossible to sharethe communication network in the typical architecture ofAutomation Systems.

C. When theylink other automation systemsThe system links directly to another automation system insystem architecture. If the system has to link to many othersystems, it needs the linker per each system. If you want to

link toN systems, you must prepareNslinker.Iv. THESOLUTION

We designed an IIG for solving communication networksproblems and suggested the designing methodsas follows.A. System Configurationwith the new architecture.Fig. 2shows the configuration of the automation systems

I GM aster Heart Bit- Other systemFig.2. The configurationof theautomation systemswthadvancedarchitecture

It is very important to keep up the pre-installed system. Wejust added the devices in the system without changing thestructureof the networks. Asadding theII G on theLAN in thesystem, automation system has the same operation. But, theIIG provides the expandability to other systems. IIG provides

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to expandability by access point. error.B. Link the Master

A master sends communication error messages to the IIGthrough TCP/IP communication. Then IIG analyzes themessages and checks the devices in sequence. Fig3. describesthe sequence of error detection procedure.

Master TT-

I lttdError

HU B. - .. ( 4 ....... ...........*T ermtnal Serveri

............M M I

4...I .

iouter- - F Error Event

Fig.4.The signal f low between network devices and the IIG

D, Link theTRSGatewayTRS Gateway has the monitoring hnction of modems. So,IIG use the information of the Gateway by TCP/IP. TRS isonly the utility own communication system in Korea. The

status information of TRS isdifficulttoanalyze due to sharedvoice data. As testing to PAD(Packet AssembleDeassembler)which converts data between TRS modem and FRU, TRSGateway gets the information about the TRS communicationline.Fig.3.The sequenceof communicationerror detection procedure v. OTHER FUNCTIONS

At first, the master sends the message of something wrongto the 110 when it cant read the statusof the remote unit. IIGchecks the status of HUB, termnal server, modem rack, publicnetwork and modemin the remote side in sequence. In Fig. 3,I 10 cant receive a remote loop back signal of remote modem.So, we can just decide that the problem occurred in remotemodem.C. Link the Networkdevices

IIG periodically checks the HUB, Termnal Server andRouter by PING command. The network devices send1IG thestatus of each port, when they recognize something wrong.I10 collects MIB(Management Information Base) of thenetwork devices and displays the status of each network deviceto the MMI monitor. I10cm moriitor the statusof the deviceandcan set the value of the status for the each network device.Fig 4. displays the signal flow between I10 and networkdevices.Bach network device supports SNMP(Simple NetworkManagement Protocol), MIB-I and MIB-11. I10 monitors linkstatus, traffic flow on the network in the real time. It canreboot the network devices and change the configuration ofdevices. IIG periodically gets the status of each port in devicesand displays on the MMI through the f3ll graphic interface.Also, IIG disablesor enables communication functions in thenetwork device, when a specific device makes communication

The man tinction of IIG is Intelligent Network& DeviceManagement. This function described above chapter. Fig. 5shows the functions of IIG.

-A nalyze and control the network devlces-P rovide Interface any communlcatlonmedla-Couvert or bypass the any protocols-Provideaccess polntsfor other automatlonsystems-Convert or bypass the any database

I-NDMS : ntelfgmtNetwork&DeiceManagemaitsystauMDI :Medla Dependent nterfaceMSAP M ultlpleSavlce AcceesPdnt MH: W - R ot 4 nterfaceM-DBI :M ultlpleDataBaseFig.5.The fknctionsof IIG

There are many communication media and protocols inutility automation systems. When the systems have to addmore services or exchange data, they need to share thecommunication media or convert data. If they dont have theproper interface for the new service, then the system expansionwould be difficult. The developed IIG supports the Media

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Dependent Interface and Multi-Protocol Interface. It providesRS-232, 422, 485, RJ -11, 45, and Optical Interfaces. For theprotocol, IIG supports DNP3.0 widespread in Korea. Most ofthe systems have used DNP3.0 as the protocol standard inKorea. Utilities nKorea studyonUCA2.0nowadaysConnecting a system to other systems is a big issue in ITindustry. There are many systems in the distribution andsubstation field such as Distribution Automation System,Distribution Information System, Automated Meter ReadingSystem, Transformer Monitoring System, SubstationAutomation System, etc. Most of the systems need to get thedata from other systemthrough simple link instead of addingmore devices.The IIG connects the substation automation system andbypass the modified data in order to get the data of substation.Fig. 6 shows the configurationsystems. between the IIG and other

Mast er

I IGOther SystemsFig.6.Theconfiguration between I1G and other systems.

VI. FURTHER STUDY110 comprehensively includes network and devicemanagement in the automation systems. But, it supportsDNP3.0 as a standard protocol. UCA2.0 may be anotherstandard protocol for the viewof the interoperability. UCA2.0isstrangein Korea. But, we, our research team, know the prosand consof UCA2.0. Some days, well apply the UCA2.0 toWearedevelopinga modem with new network managementbctions because some modems can't support Remote Loop

Back test.IIG is now operated in real field. Well test the IIG invarious environment and analyze the data for improvement oftheIIG.

iia.

VII. CONCLUSIONThis paper describes the development of Integrated andIntelligent Gateway which is under test. The network operatingtechnique in this paper can identifies the causes of thecommunication faults, and can avoid communication networkfaults in advance. Utility companies spend large financialinvestment and time for supplying the stabilized power. Sincethis is deeply related to the reliability of Automation Systems,it is natural to employ Fault-Tolerant communication networkfor Automation Systems.Use of the network system developed in this paper is notlimted in DAS. It can be expandable to the many kinds of dataservices for customer. Thus this paper suggests the direction ofthe communication network development.For the future, the possible problems for applying differentdata services, expansion of bandwidth, reliabilityso onwill beanalyzed. Also, availability through field tests and Mean TimeTo Repair(MTTR) will be calculated.

VIII. REFERENCESRajeev Agrawal, "DA Drives Communications Backbone networks",DA/DSM '95 Asia, p.283.Terry, Devaney, "Successfid Communication Techniques forDistribution Systems", DA/DSM '95 Asia, p.297.J akob Germann and Adrian Willimann, "The PIA solution-cost effectiveacquisition and distribution of information between electrical powersupply companies n one integrated network," in Proc. Cigre 2000, 35-101.KEPCO Distribution Department, "Estimationo DAS in Operation&Construction, 2001 '',KEPCOCentral Education Center, 2002, p93.

Ix. BIoGRAPHlESM yongsoo Ki m was born in Korea, onJ anualy 5, 1970. He graduated from theMyongJi University and received B.E. degree

from the MyongJ i University, Korea, in 1996.His special fields of interest are util ityautomation and communication included utilityprotocol.He is presently a semior researcher of thecomputer communication group atKEPRI (Korea El ectric Power Research Institute),Daejeon, K orea.

Duckhwa, Hyu n was born in CheJu, Korea,on September 22, 1952. He received the B.E.degree from the Y onSei University,Seoul , Korea,in 1991. In 1987, He joined the KEPCqK oreaElectric Power Corporation)R&D Center.Since1987, He has been engaged in researchon power line and optical communicationtechniques. He ispresently a team l eader of theComputer & communication Group atKEPRI(K orea Electric Power Research Institute),Dae J an , K orea. His special field of interest isPower L ine Communication,

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automation systems in pow er utilities

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