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The increasing of large-scale wind power integration capacity brings great challenges to the safe operation and management of power grid. Modern grid codes put forward the requirements of fault ride through (FRT) capability: (i) to remain continuous operation at a given time; (ii) to contribute to support the voltage stability during FRT by providing reactive current. Aiming at the FRT problem of doubly fed induction generator (DFIG), critical elements of the rotor side converter (RSC) and the grid side converter (GSC) to FRT are analysed, and the improving RSC control scheme, adding extra hardware equipment, and improving reactive current control scheme are studied. Matlab/Simulink simulation studies are conducted to verify the effectiveness of the proposed strategies. The results show that when the grid fault is light, the improving RSC control strategy can effectively control the rotor winding overcurrent, when the grid fault is serious, it needs additional hardware equipment; the coordinated control strategy of the RSC and the GSC providing reactive current support is identified as the most advantageous approach because it not only provides enhanced reactive support for the grid, but also avoids over-speed risk of DFIG based wind turbine shaft.

The increasing of large-scale wind power integration capacity brings great challenges to the safe operation and management of power grid. Modern grid codes put forward the requirements of fault ride through (FRT) capability: (i) to remain continuous operation at a given time; (ii) to contribute to support the voltage stability during FRT by providing reactive current. Aiming at the FRT problem of doubly fed induction generator (DFIG), critical elements of the rotor side converter (RSC) and the grid side converter (GSC) to FRT are analysed, and the improving RSC control scheme, adding extra hardware equipment, and improving reactive current control scheme are studied. Matlab/Simulink simulation studies are conducted to verify the effectiveness of the proposed strategies. The results show that when the grid fault is light, the improving RSC control strategy can effectively control the rotor winding overcurrent, when the grid fault is serious, it needs additional hardware equipment; the coordinated control strategy of the RSC and the GSC providing reactive current support is identified as the most advantageous approach because it not only provides enhanced reactive support for the grid, but also avoids over-speed risk of DFIG based wind turbine shaft. [ABSTRACT FROM AUTHOR]

The continuing growth of an offshore wind farm integrated into a power grid via high-voltage DC has posed great challenges for automatic generation control (AGC) of the power system. To address these challenges, a new concept of 'dynamic dispatch of AGC units (DDA)' under control performance standards from the view of economic dispatch (ED) has been proposed in the previous work, and proved to be an effective technique to co-operate the AGC units with different ramping rates and to fill the gap between ED and AGC. However, the existing DDA model is deterministic in nature, which can hardly deal with the uncertain forecasting error of the offshore wind power output. A novel stochastic DDA model based on chance-constrained programming is proposed considering a random offshore wind power forecasting error, and a hybrid algorithm combining the evolutionary programming algorithm and point estimate method is then developed to solve the stochastic model. Numerical results from a two-area test system with additional offshore wind power generation demonstrate the accuracy and computation efficiency of the hybrid algorithm and the benefits offered by the stochastic AGC dispatch method. [ABSTRACT FROM AUTHOR]

The continuing growth of an offshore wind farm integrated into a power grid via high-voltage DC has posed great challenges for automatic generation control (AGC) of the power system. To address these challenges, a new concept of ‘dynamic dispatch of AGC units (DDA)’ under control performance standards from the view of economic dispatch (ED) has been proposed in the previous work, and proved to be an effective technique to co-operate the AGC units with different ramping rates and to fill the gap between ED and AGC. However, the existing DDA model is deterministic in nature, which can hardly deal with the uncertain forecasting error of the offshore wind power output. A novel stochastic DDA model based on chance-constrained programming is proposed considering a random offshore wind power forecasting error, and a hybrid algorithm combining the evolutionary programming algorithm and point estimate method is then developed to solve the stochastic model. Numerical results from a two-area test system with additional offshore wind power generation demonstrate the accuracy and computation efficiency of the hybrid algorithm and the benefits offered by the stochastic AGC dispatch method.