Abstract
We have developed the Reliability Analysis System for Protection Relays (RASPR) in which equipment data and failure data of Electric Power utilities in Japan except the Okinawa Electric Power Company have been stored since 1997. By using the data, we have proposed the extension of the periodic testing interval of digital relays and reduction of the testing items in a periodic testing, based upon the statistics and the reliability analysis result, and we have estimated quantitatively the effect of the automatic supervision of a digital relay. On the other hand, the second generation digital relays have been widely used from the background of the progress of hardware and soft ware technology, but the analysis based on the features of failures is not clear.
Actual conditions of equipment and the failure for digital relays and the analysis result of reliability by using the data for 11 years that have been stored in RASPR, are described in this paper.
So, in this paper, analyzing the data for 11 year stored in RASPR, the features of the failure are clarified from the analysis of the failure found by the incentives of finding failure except automatic supervision, and we list up the items on which should be concentrated in maintenance. And we show the decrease of the reliability for the first generation digital relays from the reliability analysis.
