Mitigation of voltage collapse caused by armature current protection

The importance of field current limiter behaviour during voltage instabilities is generally known. A field current limiter will weaken the system by introducing extra reactance. A tripping of the generator by an armature overcurrent relay or the activation of an armature current limiter will severely cripple the power system which often causes the breakdown of the system voltages. One way to alleviate the influence of the armature current protection during the instability is to make small changes in the active power production of the generator and thereby fully utilize the capability of the generator. Depending on the location of the overloaded generator, different actions can be taken to support the critical area as long as sufficient transmission capacity and that active and reactive power reserves are available remotely. This active power rescheduling may also alleviate the influence of a field current limiter. Some simulations are shown for a power system with a radial structure