New On-line Rotor Ground Fault Location Method for Brushless Synchronous Generators

This paper presents a new on-line method for testing brushless synchronous machines able to detect and locate a ground fault in the excitation winding of the main machine, without the need to remove the rotor. The method is based on the analysis of the voltage measured in a grounding resistor and on the measurement of the exciter field current. The grounding resistor is installed between the neutral of the exciter armature and ground. The method has been validated by experimental tests using a special laboratory setup.