Power System Transient Risk Assessment Base On Preselection Fault Set

Transient stability assessment is an important part of the power system security analysis. The evaluation results of traditional deterministic methods are conservative, can not be able to meet the requirements of stability assessment of modern grid which is looming operating limits. Risk assessment method, taking into account the possibility and severity of failure, can coordinate security and economic contradictions, has a good application prospect. The main problem hinders the practical application of power system transient risk assessment in the grid is its analysis speed issuse. In order to solve this problem, this paper proposes a transient risk assessment method based on preselection fault set. The idea is that defining a complete failure mode librarie firstly, combining failure mode with grid component models to form the anticipated fault set. And then a preselect fault set can be achieved through rapid screening technology witch can filter out most of the harmless faults in the anticipated fault set. Finally, a detailed time-domain simulation analysis of preselected fault set will be proceeded to calculate the corresponding risk indexs. Therefore, this paper has carried out the work as follows:Proposed algorithm framework of power system transient risk assessment based on preselected fault set. Firstly, transient risk assessment probability model was introduced in detail, including probabilistic model of failure, fault type distribution model, protective action and reclosing probability model. Then, the time factor is introduced into utility theory to build transient risk index system, the use of AHP computing system integrated risk indicators, using the analytic hierarchy process (ahp) to calculate the comprehensive risk index of system.Studies the fault management technology, including automatically generated technology and rapid screening technology of anticipated fault set. A complete anticipated fault set can be obtained by combining the mode library and components, then using fast time-domain simulation method tc calculate the performance index of the failure. After processing performance indexs, use it to filter the anticipated fault set.According to the proposed algorithm and theory, using Visual Studio C# programming language and Oracle database to development power system transient risk assessment software, and apply PSD-BPA software interfaces to ensure software reliability. On this basis, the use of software for IEEE 9-bus system transient risk assessment verified the effectiveness and practicality of the proposed methods and the development of software.