Application of a mobile medium voltage sub-cycle transfer switch

This paper presents the application of a mobile 3/spl phi/ medium voltage sub-cycle transfer switch (MVSTS). This application is a 15 kV class switch rated at a continuous current of 600 A. The function of a sub-cycle switch is to maintain AC electrical power to a critical load by switching between 2 independent sources within 4 ms. This switching time is sufficiently fast to preserve the operation of even the most sensitive customer equipment loads during distribution system disturbances such as voltage sags or swells. The mobile unit will allow a quick installation to a customer's facility for temporary reliability assurance in a preferred/alternate or split-bus arrangement. This application also gives a customer the flexibility of trying the MVSTS before committing to a permanent installation.