Cost assessment of maintenance alternatives on generators with stator winding water leaks

Increasing incidents of water leaks in the electrical insulation of water-cooled stator windings in large generators is causing concern to power utilities because of the decrease in the reliability of the power generating units and large potential repair costs. Several maintenance and monitoring alternatives have been developed which can mitigate this problem. EPRI sponsored a project to develop software (Generator Stator Winding Leak Decision Advisor, or SLEAK), which calculates the costs of various maintenance alternatives based on the probability of the leaks occurring, their severity, the capital cost of completing the winding leak repairs and the consequential costs from the probabilities of sudden future failures. The program uses decision tree analysis for decision making and risk assessment.