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Improvement of electricity quality is required more than before with the recent rapid spread of power electronics equipment and electronic device. GCB is a keystone of protection equipment of electricity system and has an important role to improve electricity quality. Therefore GCB is expected to have high operation reliability for interrupting fault current and/or switching all kinds of circuit such as shunt reactor/capacitor. Surveys of GCB reliability were carried out by IEE, ETRA, CIGRE and so on domestically and internationally, and the reports and papers were published. For improving GCB reliability, it was considered to be useful to analyze and reevaluate these data adding new information and to investigate technology and approach concerning reliability. The following 1) - 4) are described in this technical report. 1) Influence on GCB duty of changes of recent electricity system and operational condition, 2) failure rate of each part of GCB, failure mode, data of aging and analysis of failure factor, based on domestic and foreign survey of reliability, 3) transition and trend of policy, technology and countermeasure for reliability improvement on development/design stage, test stage in factory and service stage in site, 4) networking of monitor control system, CSS(controlled switching system) and FCL(Fault current limiter) as new technology for reliability improvement. This technical report would like to contribute to future improvement of GCB reliability, development of new technology for reliability improvement, rationalization of maintenance of GCB and establishment of life evaluation. |
