Multi-machine Power System PSS Research Based On Wide-Areas Measurement System

With the increase of electricity demand and the expanse of power system, the power system stabilizers based on a single machine infinite bus system can not adapt to restrain low frequency oscillations and obtain better damping effects in multi-machine power system which is operating at different loading conditions. Because the non-linearity, the reciprocities among generators and power system stabilizers, the optimal design need consider a lot of problems, which mostly come down to best installations and parameters tuning.Traditional PSS usually feedback local machine signal (such as the rotor speed and the electromagnetism power etc.), these signal can not reflect the Local mode, cause the results of traditional PSS restrain low frequency oscillation of the Local mode not obvious than the Interarea mode. While using for rastrain the Local mode, the parameters harmonizing of the PSS will be difficult. Therefore, leading into the distant signal in the PSS for trstrain low frequency oscillation is very necessary. In recent years, the Wide-areas measurement system based on GPS and PMU develop quickly. It can be high accuracy collects the parameter and providing the dynamic state information of the power system, providing a possibility for the PSS that designs distant signal of feedback thus.Based on the present ideas, this paper has further studied the reasons of low frequency oscillations and the methods harmonizing stabilizers in multi-machine power system. Because the reasons of the low frequency oscillation in multi-machines is complicated, this paper will use the method of character analysis to find the low frequency oscillation model in the multi-machines, and further research the possibility of install PSS to the power system. Introduction of the angle measurement technology, comparison of kinds of analyses for eletromechanical oscillation, application of measurement in Prony method to the data obtained through wide-area measurement in power system analyses are studied in the paper.In the end, this paper presents a method of design self-turning PSS based on wide-areas measurement and Prony algorithm.