Survey on industry practices and effects associated with the cutting out of stator coils in hydrogenerators

Summary

This TB presents the results from a survey on industry practices and effects associated with the cutting out of stator coils in hydro generators. The survey looks at the circumstances of the fault, techniques used to locate the faulted coil; cutting out practices and problems encountered after having cut out coils, prediction and/or measurement of the current unbalance among others. The TB also includes an educational section that covers how to read and draw stator-winding diagrams, and technical guide on how to find a fault, the repair the fault, electrical tests and measurements to return the generator to service etc. The survey revealed the lack of commercially available tools for the calculation of circulating currents, new stator winding temperature rise and generator derating with considerations to the number of cut out coils etc.

Additional informations

Authors

C. MILLET, J. AKIROR

Keywords

cut-out coils, stator winding diagram, stator fault, Winding repair, hydro generators, cutting out practices