极端事件对配电网运行安全构成严重威胁,准确高效地评估配电网的概率风险具有重要意义。为解决传统蒙特卡洛模拟(Monte Carlo simulation,MCS)效率低和现有代理模型在低概率区域精度不足的问题,提出了一种兼顾计算效率与精度的风险评估...极端事件对配电网运行安全构成严重威胁,准确高效地评估配电网的概率风险具有重要意义。为解决传统蒙特卡洛模拟(Monte Carlo simulation,MCS)效率低和现有代理模型在低概率区域精度不足的问题,提出了一种兼顾计算效率与精度的风险评估方法。首先,基于核密度估计(kernel density estimation,KDE)构建了分布式电源出力的非参数概率模型,并结合指数分布和天气因子进行设备状态的动态概率建模。然后,将输入样本分为支路故障和非故障两类。非故障样本使用多项式混沌展开(polynomial chaos expansion,PCE)代理模型快速计算概率潮流;对故障样本,建立拓扑重构模型进行优化潮流计算,以准确捕获拓扑变化下的系统风险。基于此,构建了节点电压越限、支路潮流过载和失负荷3个风险指标,并通过博弈论的主客观组合赋权法确定指标权重,得到综合风险评价值。最后,基于IEEE33与IEEE118节点配电系统的仿真分析表明,该方法能够有效应对极端事件引起的拓扑不确定性,提高风险评估效率与准确性。展开更多
In order to overcome the limitations of traditional methods in uncertainty analysis, a modified Bayesian network(BN), which is called evidence network(EN), was proposed with evidence theory to handle epistemic uncerta...In order to overcome the limitations of traditional methods in uncertainty analysis, a modified Bayesian network(BN), which is called evidence network(EN), was proposed with evidence theory to handle epistemic uncertainty in probabilistic risk assessment(PRA). Fault trees(FTs) and event trees(ETs) were transformed into an EN which is used as a uniform framework to represent accident scenarios. Epistemic uncertainties of basic events in PRA were presented in evidence theory form and propagated through the network. A case study of a highway tunnel risk analysis was discussed to demonstrate the proposed approach. Frequencies of end states are obtained and expressed by belief and plausibility measures. The proposed approach addresses the uncertainties in experts' knowledge and can be easily applied to uncertainty analysis of FTs/ETs that have dependent events.展开更多
文摘极端事件对配电网运行安全构成严重威胁,准确高效地评估配电网的概率风险具有重要意义。为解决传统蒙特卡洛模拟(Monte Carlo simulation,MCS)效率低和现有代理模型在低概率区域精度不足的问题,提出了一种兼顾计算效率与精度的风险评估方法。首先,基于核密度估计(kernel density estimation,KDE)构建了分布式电源出力的非参数概率模型,并结合指数分布和天气因子进行设备状态的动态概率建模。然后,将输入样本分为支路故障和非故障两类。非故障样本使用多项式混沌展开(polynomial chaos expansion,PCE)代理模型快速计算概率潮流;对故障样本,建立拓扑重构模型进行优化潮流计算,以准确捕获拓扑变化下的系统风险。基于此,构建了节点电压越限、支路潮流过载和失负荷3个风险指标,并通过博弈论的主客观组合赋权法确定指标权重,得到综合风险评价值。最后,基于IEEE33与IEEE118节点配电系统的仿真分析表明,该方法能够有效应对极端事件引起的拓扑不确定性,提高风险评估效率与准确性。
基金Project(71201170)supported by the National Natural Science Foundation of China
文摘In order to overcome the limitations of traditional methods in uncertainty analysis, a modified Bayesian network(BN), which is called evidence network(EN), was proposed with evidence theory to handle epistemic uncertainty in probabilistic risk assessment(PRA). Fault trees(FTs) and event trees(ETs) were transformed into an EN which is used as a uniform framework to represent accident scenarios. Epistemic uncertainties of basic events in PRA were presented in evidence theory form and propagated through the network. A case study of a highway tunnel risk analysis was discussed to demonstrate the proposed approach. Frequencies of end states are obtained and expressed by belief and plausibility measures. The proposed approach addresses the uncertainties in experts' knowledge and can be easily applied to uncertainty analysis of FTs/ETs that have dependent events.
