Control System for Active Damping of Inter-Area Oscillations

Organization: Sandia National Laboratories
Co-Developer(s): Montana Tech University, Bonneville Power Administration
Year: 2017

Currently, the only approach to mitigating grid oscillations and avoiding blackouts is to operate well below transmission capacity, which is not very economical. The Control System for Active Damping of Inter-Area Oscillations uses measurement data, acquired in real-time, from phasor measurement units, recently installed throughout the western North American Power System (wNAPS). This measurement data serves as a feedback signal to inform the controller as to how much power to add or subtract to the power flow on the high voltage (500 kV) direct current (HVDC) transmission line, known as the Pacific DC Intertie (PDCI). The controller then modulates the power flow on the PDCI. This carefully controlled “injection” of power to the PDCI is the action that damps oscillations in the grid. A supervisory system, integrated into the controller, ensures a “do no harm” policy for the grid in which damping is never worsened. Through its improvement of damping to these inter-area oscillations, the control system has the potential to allow increased power transfers in the wNAPS.