MOTOR DRIVE WITH ELECTRONIC CONTROL FOR HVAC CIRCUIT-BREAKERS

摘要

Over the last twenty-five years, substantialprogress has been made in increasing the reliabilityand reducing the maintenance requirements of SF6circuit-breakers. The most successful approachesin these respects have focused on modular designswhich reduce the number of components in theinterrupter. The majority of circuit breakers ratedabove 72,5 kV manufactured today incorporaterelatively simple yet reliable SF6 interrupters.In contrast to the major leaps in performance madein interrupter technologies, circuit-breakeroperating mechanism (or drive) designs have seenless dramatic development in core functionalperformance during the past fifty years. There havebeen major differences in the type of operatingprinciples applied (i.e. pneumatic, hydraulic andspring). But while there may appear to be a widerange of operating principles for circuit-breakerdrives, they all share a common basis in beingcomplex mechanical designs and essentially allperform the same core function of closing andopening of the circuit-breaker.From a statistical point of view, most major andminor circuit-breaker failures can be traced to theoperating mechanism. Modular design, extendedmechanical endurance testing and field experiencehave all contributed to raising the performancelevel of circuit-breaker drives. Nevertheless, everincreasingdemands for power system availabilityrequire that equipment availability be continuallyimproved.Currently, there is greater focus on increasing thefunctionality of power system apparatus to improveelectrical power quality and facilitate better systemasset management. Unfortunately, conventionalmechanical drives are inherently limited in theirfunctional flexibility.In order to overcome the limitations ofconventional operating mechanisms, it is necessaryto employ new principles. Now, a new operatingmechanism technology, “Motor Drive”, has beendeveloped. This new technology, based on anelectrical system design, offers additional benefitscompared with conventional operatingmechanisms, while at the same time overcomingprevious limitations, particularly with respect tosignificantly enhanced functionality.This paper briefly discusses the benefits andlimitations of conventional operating mechanismsand introduces the design of the a new operatingmechanism, Motor Drive, its features and thetesting performed to prove its capabilities.