Implementation Of Communication Protocol Of ZXD-100Line Selection And Location System

With the improvement in automation of electric power systems, widespread constructionof Digital substation based on IEC61850standard will become a reality. At present, Becauseof the state support for digital power grid development, the high-pressure system110kV andabove is the promotion of digital substation,35kV and below power distribution network willgradually realize digitalization.6~35kV low voltage distribution networks in China are used in non-effectively earthedneutrals system, Single-phase to earth fault has a high failure rate in Middle voltagedistribution networks, More than80percent of the fault in the distribution network issingle-phase.In order to ensure the safety of long-term operation of the distribution network,to improve the reliability of power supply, timely and accurate fault line selection and locationhave great significance. So we should also have the corresponding research andimplementation in the digital substation.In this paper, firstly the present development situation of IEC61850standard aresummarized, methods of line selection and location in small current grounding fault aresummarized. This paper introduces the DC injection line selection and location method. Thestandard content of the IEC61850are introducted, especially the main characteristics such asthe separation、function and communication object modeling technology、SCSM、ACSI、SCL are described in detail.In this paper, I use IEC61850substation network communication standard to realize DCinjection method of line selection and location system. Analysing the function of the wholesystem, decomposition of function are based on the IEC61850standards, the DC injectionline selection and location system is abstracted into several logical nodes such as PSPE (lineselection host logical node), PFSE (location logical node), RSE (fault line detection logicnode) and PDIE (DC logical node), at the same time we set up the PSLP (scheduling logicnode),then the data the logical node are described. Then I establish logical device model, andI establish the intelligent electronic equipment line selection and location system (IED)models such as IED-SEF (line selection host model), IED-FSE (position detector model),IED-RSE (line detector model), IED-DIE (DC device model) and IED-ME (host model). Because of the control command transmission by way of peer-to-peer, sampled valuetransmission by way of client/server, respectively in two ways to design the communicationprogram, I use GOOSE message to achieve transmission of the control command and useMSV to implement the transmission of sampled values. According to the variety of messageformats, each state of line selection and location system are defined,so I complete thepreparation of GOOSE、SMV message. And then I use the c++language to develope afriendly visual operation interface, using TCP/IP protocol to complete the entirecommunication service process, realizing the function of each part of the whole systemdebugging. In the software environment, I simulate the communication process of ZXD-100line selection and positioning system based on IEC61850,the interface show the faultinformation.