The Risk Assessment Optimization for the Relay Protection System Based on Proportional Intensity Model

A risk assessment optimization method for the relay protection system based on the proportional intensity model (PIM) is proposed. The operating and monitoring information is used to evaluate the equipment condition, and the minimal risk costs per unit time are obtained considering maintenance costs and failure costs. Firstly, the optimal risk assessment model based on PIM is established. Secondly, the parameter estimation for PIM according to the operating and monitoring information as well as the calculation method for failure rate are given. At last, the proposed risk assessment optimization method is used for the protection devices and transformer secondary circuits in different regions. The simulation result shows that the proposed method can evaluate the minimal risk costs for relay protections according to their operating environments, which provides the theoretical basis for maintenance works.