Research On Wide Area Backup Protection Algorithm And Trip Strategy

With the increasingly complex structure of power grid and various modes of operation of power system,the traditional backup protection is becoming more and more difficult to adapt to the rapid development of power grid.In the panorama of information under the background of wide area protection system will protect the entire global power system relay protection power system from the local to the protection function of epitaxial single element,which can obtain larger regional information protection mode to solve the traditional backup protection coordination;time delay,misoperation of protection has a positive effect caused by cascading trip problems.The range of fault disturbance is limited,and the information closer to the fault point can reflect the failure effectively.By analyzing the transmission characteristics of the initial traveling wave during component failure,an adaptive fault area recognition method based on traveling wave information is proposed.The traveling wave time information can represent the distance to the fault point,and a suspected fault area with a logical radius of 2 and a radius of 3 is formed at the center of the substation which first detected the traveling wave,By this method,the protection scope of the system can be locked in a smaller area near a fault point,so as to realize the "rough location" of the fault area.The wide area backup protection only dependent on single information source is difficult to meet the requirements of correct identification of fault components in case of incomplete information or information error,so TOPSIS-based wide area backup protection algorithm is put forward.Firstly,switching value and electrical quantity with synchronization resistance from different information sources are selected as evaluation index.Then,TOPSIS is used to calculate the distance between each evaluation index of each suspected fault components and ideal solutions,and two standards of being close to positive ideal solution and being away from negative ideal solution are taken as the criterion for evaluating various suspected fault components.Finally,fault components are identified according to the comprehensive evaluation index.This paper conducts emulation proof on IEEE 10-generator 39-bus system,which shows good fault tolerance of algorithm.In order to minimize the range of fault isolation and achieve the rapid self-adaptive trip of large-scale interconnected power grid,a wide-area self-adaptive tripping strategy based on graph theory search technology has been proposed.Starting from the graph theory perspective,the protected element-circuit breaker adjacency matrix and circuit breaker adjacency matrix are set up,and the adjacency matrix is modified based on the operation state of the circuit breaker;with fault element or failure circuit breaker as source point,circuit breaker paths connected with source point is obtained through Dijkstra algorithm.Finally,self-adaptive tripping strategy is established by the distance values and paths.According to the examples analysis,the method proposed can be used to achieve the online search of tripping circuit breaker based on the real-time topological structure of the power grid,fault element position and circuit breaker state,and the tripping strategy can be used to meet the coordination requirements of wide area backup protection.