Repairing Mechanical Damage to Stator Winding Coils in Generators

摘要

Sometimes hydrogenerator stator winding insulation is damaged due to mechanical impactrnduring operation, or more frequently, mechanical damage is done to the insulation during wedgernreplacement or rewinding. For example, damage to the groundwall insulation due to chisel orrnhammer impact can sometimes occur during rewedging. Under certain circumstances it isrnpossible to repair the stator coils and bars in situ, without having to replace the coils. This paperrndiscusses the results of a recent EPRI project to provide guidance of when such localizedrndamage can be reliably repaired, and outlines the basic repair methodology. The paper showsrnthat the repairs are able to withstand AC hipot test levels that exceed the requirements for arnnew stator winding.