1、IEC 60870-5-104-the new solution for communication in substationsMichael Eckl,Reinhard KrugVA TECH SATAustria VA TECH SAT GmbH&Co,Ruthnergasse 1,A-1210 Vienna,AustriaAbstractCommunication to and within substations iscurrently one of the main issues in substationautomation.Existing protocol standards
2、,based onthe IEC 60870-5-1 to 5 Stds.,i.e.IEC 60870-5-101Telecontrol tasks Load Dispatch Centre(LDC)tosubstation and IEC 60870-5-103 Informativeinterface to protection equipment,are well defined,mature and used world-wide.The recently releasedIEC 60870-5-104 combines the experience gainedwith IEC 60
3、870-5-101 with the modern protocol ofTCP/IP over Ethernet.New tools can supportexisting object oriented engineering combined with astation bus based on IEC 60870-5-104.Communication StandardsWhen Remote terminal units(RTUs)wereintroduced,communication between substationsand the LDC was required.Due
4、to the lack ofstandards and limited communication technology,equipment vendors used proprietary protocolsoptimised to make maximum use of the availablebandwidth.Utilities became dependent on a chosenvendors equipment resulting in the need forexpensive gateways to interface between differentequipment
5、s in system extensions.The need forstandardisation became evident,consequentlyinternational standards were defined,the IEC 60870-5-1 to 5 series,which covered the basic methods forremote communication and defined important issueslike interoperability and data integrity,also defininga profile for RTU
6、s in IEC.-101 and consequentlycreating a standard for interfacing protection relaysi.e.IEC.-103.These two standards are now appliedall over the world and are supported by nearly allmajor vendors of RTUs,substation automationsystems,and protection relays.The informationavailable via communication bec
7、ame moresophisticated when microprocessors were employedand Intelligent Electronic Devices(IEDs)started tochange the architecture of control equipment insubstations.The increasing information available from modernIEDs and higher level functionality at the bay levellike interlocking schemes covering
8、several bays,make the need for a more intensive communicationbetween the different substation functions evident.The station bus meets this need providing an openand reliable method of transport that is highlyavailable and which provides scaleable solutions forsubstations of different size and import
9、ance at MV,HV and EHV levels.In addition a solution has beenprovided for the refurbishment/expansion ofexisting substations,taking into account that60870-5-101/103 Stds.are used in manyinstallations and gateways have been avoided.During the last decade the design of LANs(LocalArea Network)typically
10、used for office automationhas changed dramatically.Modern concepts,basedon high speed(up to 1 GBit/s)switched Ethernetmakes state of the art network design a reliable andscaleable solution.The use of TCP/IP protocol andEthernet guarantees a stable and very wellstandardised platform for both users an
11、d vendors.Today Ethernet is superceding other existing LANand bus-solutions,practically becoming the world-wide LAN standard.This well proven network platform was,therefore,chosen to be used also for Utility applications.Inalmost all primary substations fibre opticconnections and new LAN/WAN technol
12、ogies areavailable.The need to adapt the existing and provenIEC.-101 protocol to TCP/IP based communicationin order to make use of new communicationtechnology was evident.IEC 60870-5-104 published by IEC TC57/WG 3offers a homogenous transition from the provenIEC.-101 to TCP/IP over Ethernet.Many alr
13、eadysuccessfully completed projects using WAN showthe benefit of employing this standard.Due to therapid development in LAN technology,switchedEthernet can be applied in the substationautomation as station bus,at a reasonable price.Switched Ethernet combined with the TCP/IP basedprotocol IEC.-104 of
14、fers state of the artcommunication technology also for substationautomation.The available baud rates can satisfyeven the highest demands for data rate in largeEHV-substations.Scaleable solutions to meet the users needsSubstation automation can be used implementedwith different levels of complexity.T
15、he variety ofsubstations(AIS/GIS,indoor/outdoor,MV/HV/EHV,refurbishment/new)puts extremely high demands onsubstation automation in terms of flexibility.Veryhigh demands are usually put on substationautomation for the highest voltage levels.This is truenot only for the IEDs,but also for the availabil
16、ity ofthe station bus.Industrial switched Ethernetsolutions can provide redundant configurations andextremely fast redundancy switching algorithms:starting with multipoint star configurations with fibreoptic for indoor switchgear,but also redundant ringstructure based on fibre optics when used in EHVoutdoor switchgear with relay kiosks(see figures 1&2).Modularity is the key to provide a system thatmeets the users needs.Stand-alone functionalityguarantees highest availability even at the bay leve
