A Method of Identifying Power System Oscillation and Tracking Oscillation Center Based on Wide Area Measurement System

With the lower communication delay and higher sampling rate, it becomes possible to use wide area measurement system (WAMS) in security and stability control of power system. In this paper, a new method based on WAMS is proposed to identify and track oscillation centers in power systems. Using the geometric relation of bus voltage phases uploaded by phase measurement unit, the method can identify the oscillation and further locate and track the position of oscillation center in real time. It is not affected by the oscillation center drift caused by the different line impedance or system voltages in actual power system, and the transfer of the oscillation center caused by the line breaking when faults superpose oscillation also have no influence on this method. On this basis, a detection criterion and a control scheme of out-of-step separation are proposed, which can determine the separation section and the period of power system oscillation dynamically. Simulation results show the effectiveness of the method.