Distribution Circuit Power Quality Considerations for Supply to Large Digital Computer Loads

A unified approach to analyzing distribution circuit power quality requirements for large digital computers is presented together with recommendations for new industry standards. The need for the recommended changes became evident during the course of a study performed by the authors to determine methods of improving the availability of a real-time computer driven Customer Information System (CIS), through improvements to the distribution feeder delivered power. A systematic procedure is presented for use by an electric utility for quailtifying the quality of power delivered. It is then shown how this information can be used by a customer to determine the need for and most economic selection of power conditioning equipment for a desired level of computer availability. A recommended format for the data to be supplied by the computer vendor and the power conditioning vendor is presented as required for the implementation of the suggested procedure.