计及时变故障率的电网计划检修启发式优化模型研究

Heuristic Optimization Model for Power System Preventive Maintenance Considering the Time-Varying Failure Rate

电力设备在运行中受老化、磨损等因素影响,故障率随时间呈增长效应,通常需要采用计划检修削弱或消除上述因素导致的故障增长率。采用二重威布尔函数描述元件故障率增长规律,推导了时变故障率下元件的平均无效度公式。通过状态枚举法和基于交流潮流最优削负荷模型对系统故障状态进行选取和最优削负荷计算,建立系统可靠性指标、系统停电成本、计划检修成本、矫正性成本与计划检修率之间的解析表达式,在此基础上推导出系统总成本对元件计划检修率的灵敏度公式,利用该灵敏度公式采用启发式迭代方式对电网各元件计划检修率进行优化。针对RBTS系统,从可靠性和经济性两个方面对优化计划检修方式和传统C级检修方式进行了对比分析,并重点研究了优化计划检修方式下电网各设备计划检修成本的优化调整规律。

Power system components suffer from aging,wearing and hidden failures in operation,thus the component failure rate is increasing over time.The preventive maintenance is the conventional method to weaken or eliminate these influencing factors.This paper describes the growing trend of failure rate using the Weibull function and derives the average unavailability formula incorporating the time-varying failure rate.Through system state enumeration and optimal load shedding models based on AC power flow,the system failure states are selected and the corresponding minimal shedding loads are calculated.Then,the analytical expressions are established for the system reliability indices,system outage costs,preventive maintenance costs,and corrective maintenance costs incorporating the preventive maintenance rate;thereupon the sensitivity formula is derived for the total system cost and each component preventive maintenance rate.Finally,this paper proposes a heuristic iterative algorithm in which the sensitivity is ranked,to find the optimal preventive maintenance.According to the studies on RBTS,it analyzes and compares between the optimal preventive maintenance and the traditional C-level preventive maintenance from the perspective of the reliability and economy,and emphatically studies the costs adjustment for component preventive maintenance.