Detection of Turn-to-Turn Faults in Large High-Voltage Turbine Generators

A modification of the method of using the surge-comparison tester was investigated in regard to detecting and locating turn-to-turn faults in the stator windings of large high-voltage turbine generators. It was found that by using the method devised, the turn insulation can be stressed to as much as several times operating conditions, and both copper-to-copper faults and arcing faults can be detected easily. Limitations of the test method were explored, and recommendations for further improvement of the test, particularly as regards increasing the amount of stress on the insulation, are made.