Diagnosis of Short Circuit Faults in Generator Excitation Winding Based on Torque Comparison Principle

For safe operation, it is necessary to monitor short circuit fault in excitation winding online. As the short circuit fault causes loss of excitation magnetomotive force, it can be assumed that the excitation winding is still normal, based on the relationship between excitation magnetomotive force and electromagnetic power, the conclusion that the expected electromagnetic torque is bigger than the actual electromagnetic torque after a short circuit fault can be got. Then the conclusion was verified using a generator 2D finite element model. This method does not rely on massive historical operating data, real-time operating data can be used to determine a short circuit fault, and quasi real time performance can be achieved, the developing trend of the fault can also be presented.