Investigation of transient phenomena of a salient pole synchronous machine during field short-circuit using FEM

Abstract

During the transient operation of a synchronous generator, a lot of variations in the operation of the machine appear, which are unavoidable and can cause significant oscillations of the load angle ș and the electromagnetic torque. These oscillations can lead the generator to pole slipping. A fault, which is possible to occur, is a short-circuit at the supply of the excitation system of the synchronous generator. In this paper we investigate the performance of the machine during a shortcircuit at the excitation, while the synchronous machine is connected to the grid. Particularly, the waveforms of all the currents, stator, field and damper, the electromagnetic torque and the field in the air-gap are derived and studied.

A Performance Analysis of a Hydrogenerator In The Case of Field Short-Circuit Using FEM

“…Just after that the torque begins to rise reaching positive values almost ten seconds after the fault. As there is no supply in the field winding there is no electromagnetic field and as a result the machine operation changes from generator to motor, but it doesn't keep this operation permanently as it happens under the consideration of constant speed [8].…”