Frequency Coordinated Control for the Asynchronous Interconnected Power System With Multiple HVDC Links

The isolation of the HVDC transmission system challenges the frequency stability of asynchronous power grid. Considering the high-capacity power regulation capability of multiple HVDC links, a novel frequency coordinated control method is proposed for the asynchronous interconnected power system. This method firstly establishes a detailed frequency response analysis model by using wide-area measurement data. Then, for the lowest frequency control after disturbance, based on the frequency response analysis model, the functional relationship between the lowest frequency and DC power support is deduced. Finally, considering the influence of multiple HVDC power support on node voltage, power flow of line and frequency variation of the HVDC opposite-end grids, an optimal model of frequency coordination control with minimal influence is established. By solving the model, an multiple HVDC coordinated power support scheme can be obtained to achieve the lowest frequency control target after disturbance. A typical IEEE system is improved to an asynchronous interconnected power grid for case simulation. The accuracy and effectiveness of the proposed frequency coordination control are verified by comparison with traditional method.