Research On Optimization Of Substation Communication System Based On IEC61850

Traditional substations use cables to connect primary and secondary equipment,and communication between devices is the core part of its business.With the popularization of intelligent substations,substations enter into a bottleneck of development,and at the same time some problems are exposed,such as the reliability,stability and safety of the components of intelligent substations,which cannot be guaranteed.The system structure of substation communication network needs to be further improved and so on.The purpose of this paper is to optimize the design of substation communication scheme by using intelligent substation technology and IEC61850 standard protocol,and to improve the real-time,availability and integrity of substation communication system.There are a lot of equipments related to communication in substations.Some of them are selected in this paper to optimize the structure or technology of some functions in the field of communication.The main work of this paper is as follows:Firstly,the optimal design of protection elements based on IEC 61850 communication is studied.In the traditional relay protection scheme,the intermediate device is used to transmit different signals between the two sides of the protection line,which affects the real-time communication.The communication standard based on IEC61850 can use communication link instead of hard-wired interface.In this paper,the serial communication based on new technology such as optical sensor is used to replace analog signal from CT and VT,and the connection between relay protection is eliminated.The direct serial communication between relays is realized to protect the protection element that transmits the GOOSE message,(SV)sample value in the substation communication system.The test results show that the performance of GOOSE-based distributed applications is always better than that of hard-wired schemes with the same function.The GOOSE-based scheme is about half-cycle faster than the hard-wired scheme.Secondly,the communication optimization design between medium voltage switchgear in substation is studied.In the single bus arrangement of medium voltage switchgear,the conventional instrument transformer(IT)is used as the measuring equipment of current and voltage.The voltage transformer(VT)is located in the branch line on the cable side,and the bus voltage is measured on the output feeder.The voltage sharing of switchgear cabinet is realized by bus-to-output feeder signal.In this paper,the NCIT(Sensor)of IEC 61850 / 9 / 2 is adopted to improve the design of switchgear,the signal sent out is routed to a IED,and the voltage data can be shared through local area network(LAN).The available voltage measurement information can be easily accessed by different IED connected to the network,and the interconnection lines of switch devices are simplified.The test results show that the solution with non-regular VT has better availability than regular VT.Finally,the optimal design of configuration description of substation communication data is studied.The system configuration description SCD file is automatically generated code,IED description is realized by C language programming and each type of SCD data is mapped directly to C data structure,thus forming the hierarchical structure of C data structure.According to the data type and requirement of SCD,the syntax and semantics are verified,the model is constructed and the code of C language environment is generated,and EMF automatically generates the Java code of the model from the XML Schema defined in IEC61850-6.Automatically generate IEC 61850 communication code that can be used for both offloading IED,and monitoring IED.The test results show that the scheme is convenient and practical in the protection and control scheme in the real-time load-reducing monitoring system.