Characteristic Analysis and Polynomial Fitting Based Compensation of the Time Delays in Wide-area Damping Control System
HU Zhi-xiang, XIE Xiao-rong, TONG Lu-yuan (Tsmghua University, Beijing 100084, China)
An inter-area damping control system based on wide-area measurements system (WAMS) can greatly improve the ability to damp low-frequency oscillation and the transfer capability of interconnected power systems. However, one of the key issues of wide-area damping control (WADC) is to appropriately evaluate the influence of time delays caused by the wide-area transfer of data and if necessary to compensate the delays to guarantee the control performance. In this paper the characteristics of communication delays of WAMS are analyzed based on the field test results. With a typical 2-area 4-machine power system, the effect of delays upon WADC systems is studied. Further, a delay compensation method based on polynomial fitting is proposed to obtain the current control actions from the delayed remote feedback signals. Digital simulation results demonstrate that the proposed method is effective when the time delays are within a certain range.