Research And Implementation Of 10kV Station Area Protection For Smart Substation

Under the background of smart grid,relay protection shows the trend of localization and regionalization.Station area protection can overcome many shortcomings of traditional relay protection by making full use of relevant technology of intelligent substation,and make it more effective to protect the safe,reliable and stable operation of power system.As the power supply terminal of 10 kV distribution equipment,in the traditional substation,limited by technical level,capital scale and other factors,10 kV part of the relay protection configuration and automatic security control is not perfect.In the intelligent substation based on IEC 61850 standard,the advantages of information sharing and computer network communication can be fully utilized to realize the 10 kV station area protection function,which makes the relay protection of 10 kV part more complete.Therefore,it is of great theoretical and practical significance to study the 10 kV station area protection of intelligent substation.In this paper,the 10 kV station area protection of intelligent substation with three main transformers and 10 kV buses connected in four sections is studied.This paper analyzes the shortcomings of 10 kV bus differential protection and 10 kV standby automatic switching-on in traditional substations,and illustrates the necessity of constructing 10 kV bus differential station area protection and 10 kV network standby automatic switching-on in intelligent substations.The 10 kV bus-to-differential Station-wide protection based on the phase comparison principle of current fault components is studied.The phase comparison based on current fault components can effectively overcome the adverse effects of load current and transition resistance,and help to further improve the sensitivity of bus-to-differential protection and the accuracy of fault bus judgment.The network automatic switching is studied based on internal bridge connection and linear variable group and 10 kV four subsection bus.The 10 kV network standby automatic switching can overcome the shortcomings of the traditional 10 kV four-section bus standby automatic switching,flexibly adapt to the changes of operation mode,and realize the functions of load sharing and overload switching,and further improve the reliability of power supply.The networking mode of 10 kV station domain protection device with related intelligent units and merging units is explained.The method of instantiation of station domain protection model is expounded.The connection relationship between 10 kV station domain protection related logic quantity and virtual terminal is enumerated.The 10 kV bus differential protection and 10 kV standby automatic switching-on proposed in this paper are integrated into a centralized station area protection device with dual configuration.Finally,the reliability of 10 kV station area protection is analyzed.The phase comparison principle of current fault component is adopted in 10 kV bus differential station area protection proposed in this paper,which can overcome the influence of load current and transition resistance,and get rid of the situation that 10 kV bus protection relies on transformer backup protection.The proposed 10 kV network standby power supply can flexibly adapt to the changeable operation mode of 10 kV multi-section buses,and make the function of 10 kV bus standby power supply more perfect.The research and application of 10 kV station area protection function provide more reliable and fast protection function for 10 kV distribution device of intelligent substation,and further improve the reliability of regional power grid.