A risk evaluation method for cascading failure considering transmission line icing

Overhead transmission line icing is one of the main factors affecting safety and reliability of power grid, and the cascading failure may occur due to the iced transmission line. In this paper, a risk evaluation method is proposed to evaluate the cascading failure risk caused by the transmission line icing. Based on the ice accretion model of the transmission line, a piecewise linear model of the transmission line failure probability considering the icing thickness is established. And the Value at Risk (VaR) and Conditional Value at Risk (CVaR) are used to evaluate the security levels of the power system threatened by icing transmission line. Simulation of an IEEE 118 system is carried out to investigate the performance of the proposed risk evaluation method. The simulation results show that the proposed method could evaluate the grid risk caused by transmission line icing. And longer icing time will result in greater cascading failure risk. Also, the cascading failure risk is affected by the position of the iced transmission line.