For the rotor speed of variable speed wind turbine (VSWT) is decoupled from system frequency, the system equivalent rotary inertia and primary frequency control ability are decreased with wind power penetration growing continuously. To solve the problems, VSWT with additional frequency control was studied. The dynamic characteristics of input and output power of VSWT during participating in system frequency regulation are analyzed. The relationships between the active power increments and the duration of VSWT participating frequency control are quantified. A coordination frequency control strategy base on time sequence control is proposed. According to the control strategy, the VSWTs can participate in frequency regulation depending on the coordination of wind speed, power increments and duration. The simulation results demonstrate the effectiveness of the proposed control strategy, which can make full use of the frequency regulation ability of VSWTs as well as minimize the negative effects on system frequency.
A Research on Primary Frequency Control Strategy
