一种基于可信性理论的电网安全性综合评估方法

An approach of power grid security comprehensive assessment based on credibility theory

现代电力系统自身的复杂性,决定其安全水平很难用单一的指标进行表征,而常规安全分析通常只能就电力系统安全的某一方面进行分析,不足以对电力系统安全进行整体的描述。从我国电网实际需求出发,建立了一套用以评价电力系统安全性的指标体系,提出了一种在评价模型中引入Gini系数的改进层次分析法(AHP)。通过采用三角模糊数描述权重,基于可信性理论求出指标的权重,用'拉开档次法'得到新的判断信息矩阵及权重系数,使对象间的差异更大。由于该模型能够最大限度地降低主观因素对评价过程的影响,指标间的协调及均衡情况在评价过程中得到反映,得出的结果有着更高的可靠性和数学理论基础。通过算例验证了所提方法的正确性和优越性。

Because of the complexity of modern power system, the security level is difficult to be characterized by a single indicator. However, the conventional security analysis usually only focuses on a certain aspect of power system security, and it is not able to have a overall description of power system safety. Starting from the actual needs of power system, this paper proposes a safety evaluation indicator system and an improved analytic hierarchy process （AHP） which introduces the Gini coefficient into the evaluation model. Based on triangular fuzzy number, the model can amend the original judgment matrix and the weight obtained by credibility theory, then amend the weight by ＂widening the difference＂ method. Those make larger variance in object. Since subjective factors can be maximally reduced in the model and the coordinated and balanced situation of the indices have been reflected in the evaluation process, the results of the assessment model proposed in this paper has higher reliability and mathematical theoretical bases. Finally, an example is provided to verify the correctness and superiority of this method.