Design And Implementation Of Substation-area Protection System Based On Smart Substation

Relay protection is an important guarantee for the safe and stable operation of power system by detecting faults or anomalies of protected objects within the scope of surveillance,and then sending out alarms to execute protective actions to isolate faults accurately and reliably.At present,the number of parallel lines on the same pole is increasingand the voltage levels of 330 k V and 750 k V UHV appear.The large investment of SVG compensation equipment makes the structure of power grid increasingly complex and flexible.However,the traditional relay protection can not solve the problem is becoming increasingly prominent.Substation protection is a new relay protection modeintegrating redundant backup protection,failure protection,simple bus differential protection,low-frequency and low-voltage load reduction,automatic switching of standby power supply and over-load interconnection cutoff and other functions,according to the international IEC 61850 communication protocol standard and taking advantage of the advantages of intelligent substation whole station multi-information sharing.In this thesis,aiming at the problems existing in traditional relay protection system and the demand of substation protection in intelligent station,a set of substation protection system is designed and implemented.The main work of this thesis is as follows:1.The related technologies of substation protection system are studied,including communication networking technology,precision clock synchronization technology of IEEE-1588,substation protection based on current differential and safety automatic control technology,etc.The deficiencies of traditional relay protection,the development needs of large power grid and technology promotion are analyzed,aiming at the status and application requirements of substation protection system.2.According to the requirement analysis,the frame structure and function modules of the substation system are designed,including sampling data receiving and receiving module,data preprocessing module,phasor calculation module and substation protection module.Based on the characteristics of the current sampling information and the sudden change of fault current in the station,a new method of substation protection treatment based on current differential is proposed.According to the principle,the total station components are divided into four differential zones(unit differential zone,line-bus differential zone,transformer-bus differential zone and multi-component cooperative differential zone).The differential starting elements are set up,various kinds of faults in the differential zone are analyzed,and the logical action is carried out.Especially when the unit differential zone refuses to move,the cooperative processing of the other three differential zones can be the most effective.Rapid and selective removal or isolation of faults is in a small area.3.Complete the development of the substation protection system,and test the function and performance of the substation protection system through the real-time digital simulation dynamic simulation platform(RTDS)of Xuchang Cape Detection Technology Center,which verifies the correctness and feasibility of the system.The intelligent substation protection system designed and implemented in this thesis has been applied in Weishan 110 k V intelligent substation of Yunnan Dali Power Supply Bureau.The results show that the system runs stably,works well and achieves the expected goal.