基于影响图和模糊概率的电网元件多准则风险评估研究

Research on multi-criteria risk assessment of power grid components based on influence diagram and fuzzy probability

电网元件风险评估过程中存在风险因素不确定性,各个风险因素评价标准也不同,使得风险变量间的关系以及可能引起的后果得不到有效表示。本文提出一种基于影响图和模糊概率的电网元件多准则风险评估方法,使用影响图确定影响风险的所有相关因素,描述其相关性,确定所有可能的替代决策,用模糊概率表示风险因素的发生概率。为便于发生概率计算,利用扩展原理将模糊对应关系扩展到标准算术运算符中。将该方法应用于少油断路器进行验证,选取天气状况、电网周围环境、电网最大负载和少油断路器工作状态4个节点作为风险因素,根据相互影响关系构成影响图,通过不同标准的安全风险和环境风险对元件运行状态进行风险评估,最终求出3种维护方案(什么也不做(Do nothing),小修(Minor),大修或更换(Major))的风险值,为维护决策提供有效依据。该方法可为电网元件维护决策过程中风险因素的有效评估提供有益参考。

In the process of risk assessment of power grid components, there are some uncertainties of risk factors, and the evaluation criteria of each risk factor is also different, so the relationship between risk variables and the possible consequences cannot be effectively expressed.In order to solve these problems, a multi-criteria risk assessment method for power grid components based on influence diagram and fuzzy probability was proposed.The influence diagram was used to determine all relevant factors affecting risk, and to descrie their correlation and all possible alternative decisions.In order to calculate the occurrence probability, the fuzzy correspondence was extended to the standard arithmetic operator by using the extension principle.The method was applied to the verification of the low oil circuit breaker.Four nodes were selected as risk factors, including weather conditions, the surrounding environment and the maximum load of the power grid, the working state of the few oil circuit breaker.The influence diagram was formed according to the mutual influence relationships, and the risk assessment of the component operation state was carried out through different standards of safety and environmental risk.Finally, the risk values of three maintenance schemes(Do nothing, Minor, MMajor)were calculated, which provided effective basis for maintenance decision-making.The method could provide a useful reference for the effective evaluation of risk factors in the process of power grid component maintenance decision-making.