Unified Residue Method for Design of Compact Wide-area Damping Controller Based on Power System Stabilizer

A wide-area damping controller (WADC) is effective in damping inter-area low-frequency oscillation (LFO), if the time delay in a wide-area control loop can be properly handled. In order to simplify the WADC design and enlarge the delay adaptation range, the classic power system stabilizer (PSS) is adopted, and a new unified residue (UR) method is proposed for compact WADC design. The strategy of control loop selection is also improved by modifying the relative residue index based on a few dominant oscillation modes. The designed PSS-based compact WADC is as simple as classic PSS with no more than two lead-lag phase compensation units. Case studies are carried out on an IEEE 16-machine 68-bus power system. Simulation results demonstrate that the control loop selection before the WADC design is necessary and that the proposed selection strategy can easily pick out the suitable candidate control loops. In addition, it is feasible for the UR method to design WADCs with different time delays in the selected control loops. All the designed WADCs are effective in damping inter-area LFO and robust to time delay variations under operation conditions. Comparisons among five design methods for PSS-based WADC show that the proposed UR method is superior in delay adaptation, the conciseness of WADC structure and computation speed of parameters.