Protection system for a shorted rectifying diode within a synchronous generator

Abstract

A shorted rectififing diode protection system for a synchronous generator having a stationary exciter field which induces a voltage in a rotating exciter armature when energized by an exciter drive current, the voltage being rectified by a plurality of rotating rectifiers and applied to a rotating field winding to induce an output voltage in a plurality of main stator output phase windings, the output voltage being controlled by a voltage regulator having peak excitation current protection means, comprises a circuit for detecting actuation of the excitation current protection and generating a field protection monitor signal, a circuit for discriminating a shorted exciter field and generating a protection lock-out signal, and a logic circuit responsive to the field protection monitor signal and the protection lock-out signal for generating a shorted rectifying diode protection signal. Upon generation of the protection signal, the system disables the voltage regulator to preclude collateral damage to the generator. The method of detecting a shorted exciter field rectifying diode comprises the steps of a) monitoring the peak current supplied to the exciter field from the voltage regulator, b) generating a field protection monitor signal when the peak current exceeds a given threshold, c) generating a protection lock-out signal if the exciter field is discriminated as shorted, d) de-energizing the generator in response to the field protection monitor signal, and e) inhibiting the step of de-energizing the generator in response to the protection lock-out signal.

Dependencies are inferred from the claim text.