Study On Damping Of SSO Based On Flexible Power Technology

With the development of economy in recent years, the load of power system increase rapidly, but the distribution of energy and load imbalance decided to take high-capacity, long distance and ultra-high voltage transmission. In order to improve economic efficiency and enhance the stability limit line to address the capacity of existing transmission lines besides to resolve the problem of low transmission, series compensation project gradually increased, but the series compensation system will bring sub-synchronous oscillation, so the research problem with SSO Strong practical and theoretical significance.Flexible power technology is accompanied by the developing of power electronics technology and the industry improves. The applications of FACTS devices in this technology, provides a power tool for damping of SSO.Based on study the mechanism of SSO, damping of SSO by SVC and STATCOM is presented in this paper.SVC as a reactive power compensation component is widely used in China's power grid, mainly using the voltage control of its target, but the research of using SVC to damping SSO is few. In this paper, the basic operation principle of the SVC and the various control strategies are all introduced in detail. Use of generator speed error signal to control SVC that installed in the middle point of the circuit is proposed to achieve the objective of damping SSO. The simulation results simulated in PSCAD/EMTDC verified this method is feasibility. Because the technology SVC is mature, so use SVC to damping SSO has strong theoretical and practical significance.STATCOM is a fully controlled device that based on GTO. Compared with SVC, STATCOM has many advantages, such as wider control range. Based on the principle of STATCOM and the research results of damping SSO with STATCOM Present using remote generator speed acceleration signal by STATCOM which located at the middle of transport lines controlled with decoupled current control method. The simulation results simulated in MATLAB/Simulink on IEEE SBM verified this method is feasibility.