Locating and Sizing Method of MMC‐BESSs for Improving Frequency and Voltage Stability of Sending‐End Power Systems With High Proportion of New Energy

ABSTRACT The battery energy storage system (BESS) based on the modular multi‐level converter (MMC) can provide frequency and voltage support for the sending‐end power system, which facilitates the large‐scale integration of renewable energy into the power grid. A method for locating and sizing of MMC‐BESSs is proposed to address the frequency and voltage stability issues in the sending‐end power systems with a high proportion of renewable energy, thereby ensuring stable system operation and minimising investment costs. First, the analytical expression of the frequency stability constraint is derived based on the primary frequency regulation model, and the sensitivity of the voltage stability margin to system parameters is derived based on the singular value theory. Subsequently, the uncertainty of the load power factor is described by the box‐type set, and a robust optimisation model for locating and sizing the MMC‐BESS considering the load power factor uncertainty is established. Then, a piecewise linear solution method is proposed for the robust optimisation method. The basic idea of the piecewise linear solution method is to decompose the robust optimisation model into a main problem for solving the location and capacity of MMC‐BESS and a sub problem for solving power flow and stability margin. The optimal solution is approximated by alternately solving the main problem and the sub problem. Finally, a modified IEEE 39‐bus is tested to verify the effectiveness of the proposed method.