|Budget Amount *help
¥2,200,000 (Direct Cost : ¥2,200,000)
Fiscal Year 1994 : ¥1,000,000 (Direct Cost : ¥1,000,000)
Fiscal Year 1993 : ¥1,200,000 (Direct Cost : ¥1,200,000)
This study has developed and practical applied an expert system for diagnosing insulation degradation of 6.6kV XLPE cables, during 2 years for 1993 and 1994. In this expert system, the main program of computer applications is written in C-language, the main inference routine is constructed by a backward inference rule of OPS83. In addition, the inference with insulation characteristic value is done by a fuzzy inference method. At the beginning of this study, a prototype expert system has been performed by using some insulation characteristic value cbtained from a power outage test. The expert system has made remarkable achievements that the diagnosis results of system almost agreed with those of the experts. However, since it is not allowed to stop the power supply for a long time, the power outage test can not be insisted as an advantageous method. And also, the insulation diagnosis analyzing only insulation characteristic value is no advantage for monitoring degradation trends of cab
le insulation. In order to correct these defects, the expert system has added a knowledge base of insulation degradation data obtained from visual inspection tests. The knowledge base has been constructed by hearing of the experts. The computer program of expert system has been modified for applying to a live-wire state of XLPE cables. In this case, the diagnosis is carried out by analyzing insulation resistance value and sheath insulation resistance value obtained from the live-wire test. The modifications have improved the diagnosis accuracy of the expert system. Since the insulation degradation differs in some conditions such as manufacturing form, installation environment and installation years, the criteria of diagnosis has reformed by reflecting the conditions in the expert system. In the system evaluation, it has been found that both results of the system and the experts coincide with each other in 85%.
Furthermore, the expert system has been improved as the insulation characteristic value is automatically inputted by a live-wire insulation diagnoser via a GP-IB cable. The live-wire insulation diagnoser has been used through the kind offer from Fujikura LTD.The improvement of system enable us to always monitor the trends and diagnose the insulation degradation. This study achieves the expert system which has excellent performance, and has practical applied the system to 6 lines of the XLPE cables operating in a factory. Less