Application and experience with a 15 kV static transfer switch

In an effort to dramatically improve reliability to a sensitive customer, Detroit Edison, a DTE Energy Company, installed a 15 kV static transfer switch (STS). This paper presents the background on the electrical system disturbances which had a negative impact on an automotive components plant served by Detroit Edison. Previous steps taken, the studies performed, planning considerations, and the most recent actions taken to resolve the reliability issues are described. In addition, the performance of the STS during its first year of service is detailed. This application demonstrates that if there is adequate isolation of the two sources for the STS, it can avoid disturbances from voltage sags and outages, thus greatly improving overall reliability for the customer.