| Abstract |
The oscillatory response of synchronous generators connected to the power-line has several disadvantages. One is that the prime mover and the generator shaft are experiencing additional stresses by the oscillating electrical torque. On the other hand the power system is disturbed by hunting generators and the associated power transients. This paper deals with new solutions for improving the transient performance of the synchronous machine, which have become available with the recent advantages of microprocessors. A first step is to reduce the destabilizing effect of the voltage regulator using a conventional generator. Further, two active damping schemes for synchronous machines, in particular these with a second field winding in the quadrature axis, are described. The method employing generators of normal construction enhances damping very well under load, but becomes ineffective at light- or no-load conditions, while the machine with two axes rotor results in a perfect, decoupled and well damped performance under all load conditions. Following computer studies, all control schemes were tested in the laboratory using a 5KW synchronous machine with salient poles and microprocessor control. The results are presented below. |
