Switchgear For Today’s Needs . . . and Tomorrow’s Power Quality Requirements.

A major computer manufacturer had extraordinary requirements for a massive 800-acre manufacturing, customer service, and sales center. The first facility in the complex was to be completed and operational in a record-breaking 62 days from the signing of the contract.

The computer manufacturer was especially interested in S&C’s PureWave® Source-Transfer System because of its ability to switch from one utility power source to another in as little as ¼ cycle. Unlike conventional source-transfer gear — which typically requires anywhere from 30 cycles to several seconds to transfer to the alternate source — the PureWave system provides virtually seamless transfer. The manufacturer’s production operations utilize sophisticated computer-controlled equipment and S&C’s PureWave system would virtually eliminate the costly impact of many power disturbances on this critical equipment.

However, conventional source-transfer switchgear would be adequate for the start-up of the complex, and the manufacturer decided to postpone its decision on the PureWave system until the need for greater power quality could be established. Thus, the goal was to design a conventional source-transfer system that could be upgraded to a PureWave system in the future without incurring the additional cost and consequences of shutting down the facility.

S&C designed a 25-kV, 13-bay metal-enclosed switchgear assembly, which serves two loops of S&C Vista™ Underground Distribution Switchgear, as shown in the one-line diagram below. The lineup of S&C Custom Metal-Enclosed Switchgear utilizes a split-bus source-transfer arrangement with separate utility sources feeding each side of the lineup. If voltage is lost on one of the sources, the S&C Micro-AT® Source-Transfer Control automatically transfers all of the loads to the remaining “good” source.

Should the S&C PureWave Source-Transfer System ultimately be installed, the switches in Bays 6 and 8 will be opened, and the lineup will be served by the PureWave system through the switches in Bays 5 and 9. The conventional source-transfer system will then be used for backup and isolation of the PureWave system. Due to the configuration of the entire system, this upgrade can be performed without requiring an outage at the facility.

This combination of conventional source-transfer gear and the ability to upgrade to a sophisticated PureWave system met the manufacturers immediate needs and left the door open for an even higher level of power continuity in the future. The initial switchgear installation (shown below) was completed in time to meet the computer manufacturer’s extremely tight construction deadline, and the complex became operational soon after. The Micro-AT Source-Transfer Control has performed impeccably through numerous severe thunderstorms to maintain power to the facility.

S&C’s up-front planning and design of the metal-enclosed switchgear will significantly reduce the time, effort, and cost that the utility and computer manufacturer will experience in the future integration of a PureWave Source-Transfer System.