Application of Resonant Grounding in Power Systems in the United States

Previous investigations indicated a trend toward increased application of resonant grounding in the United States. The application of resonant grounding in power systems operating at voltages from 2.4 kv to 230 kv has been analyzed on the basis of answers to a questionnaire received from all organizations using such grounding. Experience with resonant grounding has been very satisfactory. The equipment requires practically no maintenance and hardly any attention since detuning is permissible within reasonable margins. The major field of application of resonant grounding is at voltages of 69 kv and below. Operation on sustained faults has been successful in many systems for hours and even days. More equipment designed for extended time rating than for ``10-minute´´ rating has been installed in the last few years. Many users of ``10-minute´´ equipment feel that operation on sustained faults would have additional advantages. ERIC T. B. GROSS is Professor of Power Systems Engineering at the Illinois Institute of Technology, Chicago, Ill., and EDWARD W. ATHERTON is with the I-T-E Circuit Breaker Company, Philadelphia. Pa. Mr. Atherton was an Instructor in Electrical Engineering at the Illinois Institute of Technology when most of this investigation was made.