Evaluation of a dynamic phasor PSS using a one-machine infinite bus system

Abstract

Phasor Measurement Units (PMU) are expected to achieve real-time monitoring and control of power systems. Dynamic phasors are derived from an improved algorithm for PMUs and they can calculate the frequency of power systems quickly and accurately. As a result, PMUs are expected to be used for not only wide-area monitoring and control but also local control, which demands high-speed control. This paper proposes applying dynamic phasors to Power System Stabilizers (PSS). A conventional PSS uses angular velocity deviation measured from a generator's mechanical rotation as an input signal. In the proposed method, however, frequency estimated from dynamic phasors from the terminal voltage of a generator is adopted for PSS input signals. To verify the accuracy, both dynamic phasors and the zero-crossing method are used to estimate frequency from the generator's terminal voltage and are compared. In numerical examples, a three-phase fault is implemented in a one-machine infinite bus test system and the damping effect of PSSs using different input signals (frequencies) estimated from the generator's mechanical rolling or terminal voltages are compared. The results show the advantage of using dynamic phasors.