Wide-Area Power Oscillation Damper implementation and testing in the Norwegian transmission network

This article reports the results from the implementation and testing of a Wide-Area Power Oscillation Damper (WAPOD) controlling a 180 Mvar TCR Static Var Compensator (SVC) installed in the Hasle substation of Norwegian 420 kV transmission grid. The WAPOD uses voltage phase angle signals from two distant locations in the Norwegian grid as inputs to the damping controller. The damping controller modulates the voltage reference set point used by the SVC's voltage controller, thereby creating a damping effect. The WAPOD is an extension to the existing Power Oscillation Damping (POD) controller that uses local measurements. A switch-over logic allows for the use of no damping control, local damping control or wide-area control. Field tests were performed during November 2011, and involved the disconnection and re-connection of a 420 kV transmission line. The performance of the WAPOD is compared to that of state-of-the-art local Phasor POD, and when no damping control is enabled. The testing results show that the WAPOD performed satisfactorily and according to the design expectations. These results show that the potential flexibility of the WAPOD to choose, among the different PMU signals, those that have the good observability of inter-area modes can be an advantage to the use of local feedback signals for damping control, as it is current practice today. Further testing of this WAPOD with other PMU signals from locations with stronger observability will be helpful to illustrate the advantage of this flexibility.