Development of Mechanical CBM System for Electromagnetically Actuated Vacuum Circuit Breaker

Abstract

A new mechanical CBM (condition-based maintenance) system for an electromagnetically actuated vacuum circuit breaker (VCB) has been developed. This CBM function has a new monitoring method using analysis of the coil current profile of the actuator operation. The VCB has three sets of vacuum interrupters, insulating rods, contact pressure springs, and electromagnetic actuators. The electromagnetic actuators control each phase independently. We have clarified the variation in the actuator's current profile by the developed analytical method when the valve of friction, contact erosion, and driving capacitance change. We have established a diagnostic method for the mechanical condition using this current profile analysis. With this method, a new remote monitoring system of the mechanical condition using current monitors on the actuator's controller has been developed and mounted on VCB for cubicle-type gas insulated switchgears rating from 7.2 kV to 84 kV. The maintenance for mechanical parts of VCB changes to the CBM system from the conventional TBM (time-based maintenance) system using this monitoring system. The developed mechanical CBM system significantly reduces the life cycle cost including the labor cost of maintenance. C⃝ 2017 Wiley Periodicals, Inc. Electron Comm Jpn, 100(2): 50-57, 2017; Published online in Wiley Online Library (wileyonlinelibrary.com).