A Control Strategy for Variable Speed Condenser Based on Doubly‐Fed Machine

ABSTRACT The lack of active power support capability in power systems with large‐scale renewable energy integration has become a significant constraint on stability. This paper proposes a variable speed condenser (VSC) control strategy based on a doubly fed machine. The rotating rotor shaft can provide inertia support for the system and participate in primary frequency regulation of wind farms or PV stations by adjusting the rotor speed. The stator of the VSC is directly connected to the grid. During short‐circuit faults, the principle of flux linkage conservation can provide short‐circuit current support for the system, suppressing transient overvoltage phenomena. Meanwhile, the fully controlled power electronic converter can provide rapid voltage regulation capability for the system. Simulation and field test results indicate that the VSC can provide stable inertia support, short‐circuit current support, primary frequency regulation and rapid voltage regulation. It can be installed in PV stations and wind farms to enhance the grid‐connection performance of renewable energy power plants.