Isolation and Suppression of Forced Oscillations Through Wind Farms Under Grid Following and Grid Forming Control

Forced Oscillations can occur even for a power system with good damping performance. With increasing high penetration of renewable energy generation towards 100% renewable generation in the power grid, exploitation of future control potential from wind turbines becomes inevitable. This paper develops an isolation and suppression method of Forced Oscillations by using wind farms (WFs) under both grid-following and grid-forming control principles. The proposed method controls a WF to absorb or release active and reactive power in a timely manner and as a result Forced Oscillations are prevented from spreading to the rest of the power grid and hence they are isolated. The Forced Oscillations of the disturbed area, which is bounded by the location of WF installation, are also reduced and suppressed. The proposed method is easy to implement and economically effective as there is no requirement of extra energy storage and power electronic devices, and a prior knowledge of the frequency of Forced Oscillations is not required. With the proposed control method, the loss of wind power capture is negligible. Furthermore, the control method is also able to damp natural oscillations. Simulations of both doubly fed induction generator (DFIG)-, and permanent magnetic synchronous generator (PMSG)-based WFs under either grid-following or grid-forming control principle, with constant or varying wind speeds and different WF locations with respect to the source of Forced Oscillations, on the modified two-area and IEEE 39-bus power systems, using Real-time Digital Simulator (RTDS) and Dymola, are used to verify the effectiveness of the proposed method.