The State Evaluation Method And Application Of Relay Protection

Regular maintenance or after-event maintenance is still adopted in the status maintenance of relay protection equipment in power industry in our country by now, and "excess" or "Inadequate" maintenance must be caused. Therefore, higher accuracy, higher reliability and wider application of evaluation method of relay protection will be researched, and the reliable preventive maintenance plan for the relay protection equipment should be provided. Expert judgment models and mathematical models are lonely used in the evaluate method and maintenance plan of relay protection system status in most time. The advantages of expert judgment and mathematical models are used adequately in this paper, which lower the evaluation result by human factors, and evaluation model of relay protection system is obtained, and the decision-making method on relay protection system is studied by this model.The evaluation method of relay protection system and the study development of maintenance decision-making was analyzed, and the disadvantages of status grading method and maintenance decision-making was summarized, and the technical specifications of evaluation and maintenance decision-making of relay protection status was got.Firstly, on-line maintenance technology failure form of relay protection system was analyzed, the failure characteristics of relay protection system obey the typical "bathtub curve", which was verified by reliability block diagram; Marquardt parameter evaluation method was analyzed, and the failure results of relay protection system based on Weibull function distribution were fitted, and the failure characteristic fitting curve of relay protection system was obtained.Secondly, the factor set and status evaluation standard were founded based on relay protection system failure mode, and the comprehensive evaluation method based on fuzzy-gray theory was put forward, and the quantification method of status comprehensive process method and judgment status level was given. The estimation method of fuzzy evaluation weights was studied emphatically, which could which lower the evaluation weighs by human factors.Then, the status evaluation results were introduced to maintenance decision-making, the real-time failure rate algorithm and parameter solving method were given, and the latest maintenance cycle based on equivalent age was deducted.Finally, the optimal maintenance strategy of single protection system was researched. Combined with the evaluation results of equipment and protection system running status, the results was imported to Markov reliability space model by failure rate form. And the optimal maintenance time by different status combination in single protection system by Matlab simulation. The guidance of the optimal maintenance time was given by the simulation results.