The use of PSS2A system stabilisers to damp electromechanical swings in medium voltage networks with distributed energy sources

In this paper, the design issue of effective damping of electromechanical swings in a medium voltage network with distributed generation by the use of a PSS2A type power system stabiliser is described. This stabiliser was installed in the generating unit with the highest rated power. Time constants of correction blocks, as well as the main gain, were determined by analyzing a single-machine system, generating unit – infinite bus. The time constants were calculated on the basis of the frequency-phase transfer functions both of the electromagnetic moment to the voltage regulator reference voltage and of the generator voltage to the voltage regulator reference voltage, under the assumption of an infinite and real value of the generating unit inertia time constant for various initial generator loads. The main stabiliser gain was calculated by analyzing the position, on the complex plane, of eigenvalues of the state matrix of the single-machine system, linearised around a steady operating point, at the changed value of this gain.