Design Of Power System Damping Controllers With Delay Considered

Low frequency oscillation is one important factor that influences the stability and transmission capacity of power system. Wide-area signals can be used for wide-area damping control because of the wide area measurement system(WAMS), however, the delay of signal acquisition and transmission is too large to be ignored. What’s more, the interactions among local and wide-area controllers reduce the control quality. So, this paper is about the damping controller design in power system with wide-area signal delay considered. Firstly, the delay power system model is built and the influence of delay on system observability/controllability and controller parameter design is analyzed. Then based on these analyses, a control loop selection method is given. The loops with large observability/controllability and small enough interactions are chosen so that the multiple controllers can be designed independently. Secondly, the separate control parameter design method is provided. One method is based on the system model and adopts the optimized algorithm to find the optimal parameters so that the delay margin is as large as possible. In this method, the Linear Matrix Inequalities based delay dependent criterions is used as the objective function and the parameter ranges are set through considering delay at the design point and relax the phase equation of residue compensation method. The other method is based on the model identification. A two-layer control structure is used to track the system model and the model predictive method is used to deal with the wide-area signal delay. The 2-area 4-machine system and New England 39-node 10-machine are taken as test systems in this paper to prove the feasibility of control loop selection method, the adaptation of two controller design methods to delay, and the adaptation of identification based controller design method to model variation.