Research On Simulation Of The Cascading Failure And Control Method In Bulk Power System

Power grid large scale interconnection has become a trend. However, theinterconnection brings challenge to the reliabilty and security while it enhances theeconomy. Researches have shown that, the large blackout often is caused by cascadingfailures. Predication of the pathes of the cascading failures accurately can prevent thereal-time cascading failures, provide the supervisory and basis of evaluation of the risks.The overloading of transmission lines is the main cause of the cascading failures,eliminating the overloading lines effectively in time can prevent the trip of the cascading,reduce the possibility of the cascading failures.Based on the existing chain failure accident chain model and power flow tracingtheory, this paper mainly conducted the following research:First of all, aiming at the line tripping effect of the uncerntainty power of the nodes,probabilistic load flow is adopted to establish the line breaking index considering theuncerntaitny of nodes. The cascading failure probability characteristic and concept of linezone are proposed. Based on the idea of flow tracing, line paritions is conducted beforethe cascading failures, considering the line tripping index and the characteristic of zones,the predication of cascading failure paths is proposed, the proposed method consideredthe uncertainty effect of the power, and considering the characteristic of cascading failureand the feature of the characteristic of zones.It can effectivly predict the occurrence ofcascading failure paths and form the events table.Then, since the cascading of line overloading is the main cause of the cascadingfailure, investigating the issue about control of the overloading lines, a improvedoverloading line control method, which is based on the flow tracing, is proposed. Thismethod stretchs back the overloading of the lines to generators, and gets the generator andload point adjustment scheme with load curtailment as less as possible. It makes the lineoverload control conforms to the actual demand. In addition, the introduction of theconcept of line overload control correction coefficient is proposed to solve the problemthat the overloading of lines in a ring network is not easy to eliminate.At last, IEEE39-node system is used as the case studies for validating the feasibilityand effectiveness of the proposed method in MATLAB software.