Coordinated Parameters Design Of Damping Controllers For Power System With STATCOMs

For China power system, due to weak connections between regional systems, low frequency oscillations have become one of constraints on the capability of power transfer among regional systems. Researches and practices on electric power engineering indicate that introduction of power system stabilizer (PSS) is an economic and effective approach to damp the low frequency oscillations. Also, the potential application of supplementary stabilizers of Flexible AC Transmission System (FACTS) for damping low frequency oscillations has received much attention in power engineering.Static Synchronous Compensator (STATCOM) is an important FACTS device. To improve the small-signal stability of multi-machine systems, the coordinated design of parameters of STATCOM stabilizer and PSS is of realistic importance. Power flow calculation is a base work of small-signal stability analysis. A new power flow algorithm which can consider the active power loss of STATCOM is presented in this thesis. The algorithm comes from a modification of the Newton-Raphson method in the polar coordinate. The algorithm can be easily implemented, with the results more precise than those of the algorithm ignoring the active power loss of STATCOM.When deriving the small-signal model of the power system installed with STATCOM, the following three linear relations are analyzed, namely, the linear relation between the increment of the active power delivered along the transmission line and the state variable, the linear relation between the increment of the projection of voltage phase vector on x-axis and the state variable, and the linear relation between the increment of the projection of voltage phase vector on y-axis and the state variable. A conclusion that, the increment of the active power, the increment of the projection of voltage on x-axis, and the increment of the projection of voltage on y-axis are irrelevant to part of state variables of STATCOM, is obtained. Applying the conclusion, this thesis uses conventional approach to derive the small-signal model.Based on the small-signal model, an optimization model for the coordinated design of parameters of STATCOM stabilizer and PSS is presented in this thesis to improve the small-signal stability of power systems. Because this model considers...