保护隐性故障及其对电力系统连锁故障发展影响

Impact of Protection Hidden Failures on the Development of Power System Cascading Failures

继电保护隐性故障是造成电力系统连锁故障的重要因素之一,针对影响保护隐性故障因素,建立了考虑线路故障的保护隐性故障模型。从人为失误、保护装置自身的老化失效、保护所处环境影响来分析保护的故障率,基于Markov状态空间法,针对高压系统两套主保护及远近后备保护,建立详细的线路—保护状态转移模型,计算保护误动概率与拒动概率,并应用到连锁故障仿真算例中。连锁故障仿真考虑不同保护动作特性、控制措施动作以及不同负荷水平的影响,根据仿真结果计算保护拒动与误动风险,分析保护隐性故障对电力系统连锁故障的影响,以及各因素对保护拒动和误动的影响。仿真结果表明,重载时保护不正确动作风险比轻载和正常工作时大。

Hidden failure of relay protection is one of the important factors causing cascading failures of power system. Consequently ,we established a model of protection hidden failure after considering the factors affecting the protection hidden failures. Meanwhile,we analyzed the protection failure rate from human error, protection device aging failure, and environment impact. Moreover, we built a model of detailed line-protection state transition based on the Markov method, which contained two sets of main protection and two sets of backup protection of high-voltage system, to calculate mal-operation probability and non-operation probability of the protection system. And the proposed method was applied to the example simulation of cascading failures. The simulation included different action characteristics of relay protec- tion and control system under different load levels and their effects on the development of cascading failures. The mal-operation and non-operation risk of protection system were also calculated, and the effects of protection hidden fail- ures on cascading failures in power system and the various factors influencing mal-operation and non-operation were analyzed. Simulation result suggests that, during heavy load condition, incorrect operation risk of protection is larger than that of normal load or light load.