Optimisation of Voltage Regulator Gains by the D-Decomposition Technique For Best Steady State Stability

The paper applies the method of D-decomposition technique for optimizing the derivative gain settings of the excitation voltage regulators of a power station for best steady state stability condition, i. e. for maximum alternator stability and best transient response for small perturbations. A suitable digital program based on the D-decomposition technique has been written for a typical two-machine system to obtain the best values of the regulator derivative gains for different operating conditions of the system which are necessary for the future design of an on-line controlled AVR*. The nonlinear change of the derivative gain settings is also compared with the usual constant gain settings from stability limit and transient response aspects. The effect of several parameters such as the electro-mechanical transient process of the receiving-end system and certain AVR feed back signals e. g. the first and second derivatives of voltage and the proportional signal of current on the quality of transient response is also investigated.