Cable Failures and Protective Relay Operation Associated with NASA Glenn's 10x10 Supersonic Wind Tunnel

During a two-month period, NASA Glenn Research Center in Cleveland, Ohio experienced two failures of high voltage cables associated with its 10 x 10 supersonic wind tunnel (SWT) and a ground problem from the local utility. This paper addresses these problems and associated relay operations. The following incidents are reviewed: 1) Failure of 6.9kV transformer drive cable and operation of protective relaying; 2) Detection of problem on First Energy's 138kV utility power system with new microprocessor based relays; 3) Failure of 138kV transformer primary cable and operation of protective relaying. All three incidents were associated with transformer K10, one of four transformers feeding the 10 x 10 SWT complex.