Fuzzy Reasoning Alarming Method And Its Application In Contamination On-Line Detecting System For Substation

The contamination on-line detecting method and fuzzy reasoning alarming model are discussed in this paper.Some basic concepts of insulator contamination are introduced firstly. Existing methods of avoiding contamination flashover and methods of detecting contamination degree of insulators are discussed in details. These methods are analyzed and disadvantages of them are pointed out.The arising mechanism and character of leakage current are analyzed. Based on these analyses, a high precise and wide bandwidth sensor is developed. The design of contamination on-line detecting system is introduced. The relationships between leakage current, environment humidity, environment temperature and level of pollution are studied, then, the problem of fixed value alarming model is analyzed. It is proposed that in order to increase the reliability of prediction, the nonlinear prediction model, which depends on the nonlinear relationships between above factors, is indispensable. Because the nonlinear relationships can hardly be obtained, a nonlinear alarming model based on fuzzy reasoning methodis developed in this paper. The fuzzy reasoning alarming has been realized by Visual Basic programming and used in practical systems.The results of theoretical analyzing and practical running proved that the contamination on-line detecting system for substation developed in this paper can be applied to the large-scale variation of leakage current, the fuzzy reasoning alarming method can predict the pollution level of insulator more accurately. A new method is given to solve the problem of alarming reliability of contamination on-line detecting system.