Effective and efficient circuit breaker analysis

Abstract

Worldwide utilities and industries have seen various technological advancements in circuit breaker (CB) testing and analysing. Yet most of the owners underperform the maintenance activity when it comes to circuit breaker maintenance and many limit themselves to an operating time test or a static contact resistance test using inappropriate test equipment. The reasons cited for this were 'complicated test procedures which involve longer outage time on the feeder', 'lack of availability of the feeder for maintenance' and 'lack of permission to remove the earth rod or earth switch while the breaker was in shutdown condition'. Also the decision making process and pin pointing the fault in a breaker after performing a basic circuit breaker test will often be a challenge. Though the basic tests like timing test on a circuit breaker provides preliminary information about the breaker condition, actual condition of a deteriorating breaker becomes obvious in a well matured state and often revealed only by a catastrophic failure while in service. Different utilities, switch gear manufacturers, researchers and test equipment manufacturers have stressed the importance of various advanced test methodologies to save time and money. Those tests include coil current analysis, dynamic resistance measurement, testing on dual ground conditions, vibration testing, first trip analysis, online testing and so on. These circuit breaker testing technologies often provide critical information of the circuit breaker and make the decision making process simple. Pinpointing the fault in a circuit breaker and attempting the maintenance activity in a very short time will be complicated if the directions guided by the test methodologies or equipments are not clear enough or easy enough. Also one particular method, tool or technology will never provide a complete solution on the circuit breaker analysis. In this paper we would like to present a report on how some of the latest technologies in the testing industry with an integrated approach of different test methods have averted major catastrophes in substations and has made the CB testing and analysing processes simple, safe, effective and efficient. (6 pages)