Mitigation of oscillations due to changing the reference signal of the excitation system using a Posicast controller

Changing the reference signal of the excitation and AVR systems is one of the excitation control methods in controlling the terminal voltage of the generator and reactive power. In most cases the aforementioned method results in transient oscillations in the output voltage of the generator that must be damped as quickly as possible. This paper offers a Posicast controller for damping the oscillations caused by changing the reference signal of the excitation system. Extensive time domain simulations and a performance index are used to validate the performance of the proposed controller. To evaluate the robustness of the designed controller, impacts of change in the operating conditions and the use of an inaccurate model of the process in the controller design stage, on performance of the proposed controller are also investigated.