The Electric Power Research Institute (EPRI) seeks $180,000 in funding from the hydroelectric industry to support research on how to restore safe operation of a generator after failure of one or more coils in the stator winding.
EPRI seeks supporters from worldwide organizations who will provide $30,000 each. Companies that fund any EPRI program can take advantage of tailored collaboration funds for up to half of their contribution, Jan Stein, senior project manager, said.
After failure of a stator winding, project personnel can isolate, or cut out, the failed coil from the rest of the winding and quickly return the units to service, Stein said. In addition, one or more healthy coils might need to be cut out from the electrical circuit to ensure the electric current distribution in the remaining winding does not cause thermal damage to the insulation.
Stein said use of such temporary repair procedures could keep a machine in service until it can be permanently repaired or replaced, providing substantial economic benefit.
The research project updates work described in EPRI report EL-4983, Synchronous Machine Operation with Cutout Coils, published in 1987. The new research, which is estimated to take 18 months, would begin as soon as all participants are identified.
Objectives of the project are to:
o Update and expand calculations about how many and which coils can be safely cut out;
o Provide guidance for performing parallel circuit current measurements to validate stator winding operation within its thermal limits;
o Learn more about the effect of the winding with cut-out coils on vertical shaft run out; and
o Document worldwide experience and practices.