Turbine generator rotor and stator winding hipot testing

摘要

An important component of synchronous machines is the electrical insulation that is used in both the stator and the rotor windings to insulate the copper conductors from ground. The stator winding insulation is exposed to continuous high ac voltages of many kilovolts in service, whereas the rotor windings (sometimes called field windings) in synchronous machines operate under dc voltage, at voltages that are usually around a few hundred volts. If the stator winding ground insulation is punctured, the machine is automatically removed from service by protective relaying. If the ground insulation fails in a rotor winding, most commonly the machine is tripped, although it is possible under some circumstances for the machine to continue to operate with a ground fault, but at great risk of catastrophic damage if a second fault were to develop. Thus, machine operators need assurance that the rotor and stator winding insulation will not fail in service.