Medium-voltage replacement breaker projects

Many of the medium-voltage (5, 15, and 38 kV) switchgear installations in service today are of the age that makes replacement circuit breakers a cost-effective investment to extend the life of the substation and improve the overall safety. Today´s replacement circuit breakers, employing the latest interrupter technology, require less maintenance, and utilize safety features that were not available on equipment designs 30 or 40 years ago. A successful project to install replacement breakers requires an understanding of the following: which IEEE standards apply to the design and testing of replacement breakers; how to determine if a switchgear installation is a good candidate for a replacement breaker project; commissioning activities that are required to assure a safe and successful startup; and impact of the change in technologies on the system reliability. This paper addresses how these topics impact a project to replace earlier vintage circuit breakers to extend the life of the switchgear installation