Damping torque analysis for DC bus implemented damping control

Damping torque analysis is a well-developed technique for understanding and studying power system oscillations. This paper presents the applications of clamping torque analysis for DC bus implemented clamping control in power transmission networks in two examples. The first example is the investigation of clamping effect of shunt voltage source converter (VSC) based flexible AC transmission systems (FACTS) voltage control, i.e. static synchronous compensator (STATCOM) voltage control. It is shown in the paper that STATCOM voltage control mainly contributes synchronous torque and hence has little effect on the clamping of power system oscillations. The second example is the damping control implemented by a battery energy storage system (BESS) installed in a power system. Damping torque analysis reveals that when BESS clamping control is realized by regulating exchange of active and reactive power between the BESS and power system, respectively. BESS damping control exhibits different properties. It is concluded by damping torque analysis that BESS clamping control implemented by regulating active power is better with less interaction with BESS voltage control and more robust to variations of power system operating conditions. In the paper. all analytical conclusions obtained are demonstrated by simulation results of example power systems.