计及时间约束的改进模糊Petri网故障诊断模型

为充分利用故障事件记录的时间约束特性,进一步提高故障诊断的准确性与快速性,建立了一种计及时间约束的改进模糊Petri网故障诊断模型。首先,分析故障事件记录的一元、二元时间约束关系,研究不确定及缺失的报警信息对故障诊断的影响,利用虚拟有向弧及Petri网产生式规则,建立改进模糊Petri网模型;之后,通过正、反向时序推理分析,获得所有报警信息应该满足的时间区间,依据所建立的状态真值矩阵有效甄别出时序不一致的报警信息;在上述基础上,制定电网故障诊断的具体流程,提出继电保护装置动作行为辨识规则;最后,通过局部电力系统的多组算例仿真和实际系统故障案例测试,证明了所建模型能有效地诊断出电网故障,并具有较高的容错性。

Fault Diagnosis Model Based on Improved Fuzzy Petri Net Considering Time Constraints

To utilize the time constraint characteristics of power system fault event records and improve both the accuracy and rapidity of power system fault diagnosis,a fault diagnosis model based on improved fuzzy Petri net considering time constraints is proposed in this paper.Firstly,the relations between unary and binary time constraints of fault event records are analyzed,and the effect of uncertain and missing alarm information on fault diagnosis is also studied deeply.The improved fuzzy Petri net model is established by using virtual directed arcs and production rules of Petri net.Secondly,the time intervals that all alarm information should meet can be acquired by the forward and backward temporal reasoning analysis,and the time sequence inconsistent alarm information can be effectively identified based on the state truth value matrix.Finally,the specific fault diagnosis process and identification rules of relay protection devices are formulated.The simulation results and a real power system fault case indicate that the proposed model can effectively diagnose power system faults,and also has much higher fault tolerance.