AN EXPERT SYSTEM FOR SETTING CALCULATION OF RELAYING PROTECTION IN HOkV POWER NETWORKS

This paper presents an expert system software for setting calculation of relaying protection in the HOkV transmission network. An expert system for protective setting includes not only a great deal of logical inference and experts' experience, but also a mass of complicated numerical computation. According to the characteristics, this thesis constructs a production-rule-based and frame-based knowledge representing system and uses accurate searching and forward reasoning to develop inference machine. The system can accomplish fault analysis and setting calculation of power networks. And it can deal with the problem of verifying the setting value. Because of a detail explanation of setting process is provided, the results would be transparent and creditable.With the development of relaying protection technologies, there was a higher demand for setting calculation. In setting process, many factors, like credible factor, are uncertain. In conventional setting method, they are chosen and determined by protective experts without disposing the uncertainties. So no one is sure that they are optimal. In this paper, we introduce fuzzy sets theory into the expert system andABSTRACTpresent an approach to process the uncertainties of setting parameter. By this way, we can get more appropriate factors so that the accuracy, reliability and practicability of the setting value are fully guaranteed. As a result, some protective setting value is easier to coordinate and the capability of the expert system was improved.In this paper, a computation example is given, some main conclusions are summarized and some proposals are suggested for further development of this software.The expert system offers an intelligent tool for setting calculation and setting value management. It is much helpful to enormously decrease workload and improve work efficiency of setting staffs. So it has a very important significance for the safe and steady running of power networks.It is valuable to practise and popularize this expert system for its strong function, friendly men-machine interface, flexible operation and running quickly.