Research On Wide-area Protection System For Smart Substation

In recent years,with the rapid development of the national economy,especially in the environment of the rapid development of smart grid,the power system voltage level also will be getting higher and higher,EHV,UHV transmission lines putting into operation,makes the relation between the regional power grid being more closely,the scale of the grid expanding constantly,switching capacity maintaining increasing,the probability of failure and instability appears also greatly increased.protection system as the "first line of defense" of safe and stable operation,the requirements is also increasing.Traditional protection can only protect the internal part of components,while ignoring the considerations on the whole system,the power system is essentially a wide-area system,the electrical components are interconnected as a whole system,the issue of protection should be considered from global perspective.This paper presents a wide-area protection system based on wide-area differential principle for the smart grid.Using a regional centralized structure to ensure the reliability of the communication system.the principle of differential based on Kirchhoffs law guarantees the reliability of the wide-area protection.Partitioning strategy of three protected areas and the associated matrix between protection IED and protected areas guarantee the smooth realization of wide-area protection algorithms.this protection system takes intelligent substation as supports,upgrade the traditional protection system from the "point" protection to the current "face" protection,it can not only achieve that after a failure,rapidly,accurately and reliably remove fault area,but also conduct online real-time security analysis for the power grid after fault isolation to determine whether the possibility of large-scale power outage will occur,and take appropriate measures to prevent large-scale blackouts system if necessary.In this paper,Simulation is based on Liaoning Chaoyang 66kV grid.using RTDS modeling and wide-area protection system closed loop simulation system.the simulation results show that:the wide-area protection system can quickly and accurately determine the various types of faults and act to accurately cut the failure area,at the same time not expand the scope of failure.It can effectively protect the safe and reliable operation of the power grid.