A Novel Unreliability Tracing Model for Buck Power Systems Based on Contingency Screening

The unreliability tracing method is an efficient tool to quantify the risk contribution of components and identify the weak parts of power system. However, the tracing process faces the same complexity concern as reliability evaluation of a bulk power system. To address this problem, this paper proposes a novel unreliability tracing method with a contingency screening model and a new tracing principle. Firstly, the bilevel contingency screening model can screen the most severe contingency, which can perform as a substitution of State enumeration (SE) and the Monte Carlo (MC) simulation in reliability evaluation. Meanwhile, the new tracing principle is proposed to incorporate the influence of failure components on load shedding so that the masking phenomenon in the tracing process can be avoided. A similar contingency reduction technique is also developed to facilitate the analysis process. Case studies on the RBTS and RTS demonstrate that the proposed method is effective in terms of accuracy and computational efficiency.