Calculation Method for Magnetic Saturation Current of Shunt Reactors Under Oscillation in Renewable Energy Power Systems

ABSTRACT The paper addresses the analytical calculation challenges for magnetic saturation current characteristics in high‐voltage shunt reactors, considering the air‐gapped core structure and nonlinear magnetisation characteristics under novel oscillatory conditions in renewable energy power systems. A piecewise analytical method is proposed to determine winding and neutral reactor currents based on magnetic circuit operational states. Electromagnetic equations are established for shunt reactors under various magnetic circuit states during oscillation. Using knee‐point as state boundaries, piecewise solutions yield time‐domain analytical expressions for winding and neutral reactor currents. On this basis, the influence of oscillatory parameters on the characteristic components of the winding current is analysed, and a method for determining the critical saturation oscillatory frequency and amplitude of the shunt reactor is proposed accordingly. Finally, a parameter‐refined shunt reactor simulation model is constructed using the MATLAB/Simulink platform to validate the accuracy and effectiveness of the proposed method, as well as its adaptability and robustness under different operating conditions.