Distribution feeder modification to service both sensitive loads and large drives

A new, intermittent load consisting of large variable speed drives had to be added to an existing 24 kV feeder for office buildings equipped with many computers of various types. A standard option of constructing a new substation or a new transmission feeder was not possible due to environmental concerns. Consequently, the existing feeder had to be modified through innovative application of a specially design harmonic filter and a distribution series capacitor so that harmonic problems, voltage flicker problems, and commutation notch problems could be avoided. The technical aspects of the problems and solutions are presented. The cooperation required between the electric utility and the customer is discussed. The expected problems are quantified, and the solution based on an innovative modification of the feeder is described together with the measurement results