An Inhomogeneous Fractional Compensation Strategy for Compensating Current Reduction in V/v Electrified Railway Power System

ABSTRACT The electrified railway power system (ERPS) features high loads and random load fluctuations. The railway power conditioner (RPC) can effectively enhance the power quality of ERPS. In full compensation (FC), the RPC requires high capacity, resulting in poor cost‐effectiveness. In existing studies, uniform fractional compensation (UFC) is proposed. UFC achieves a lower compensation rating than FC by reducing the target power factor (PF). However, UFC mandates identical PFs across all three phases on the primary side. This strict constraint limits its flexibility in minimizing the compensation current. This paper proposes an inhomogeneous fractional compensation (IFC) strategy. IFC cancels the requirement that the primary three‐phase PF must be consistent. This allows further exploration of the current lower limit of compensation. While meeting power quality standards, IFC significantly reduces compensation capacity compared with UFC and FC. Without enforcing uniformity of PFs across the primary three phases, IFC cannot directly calculate the optimal working point for compensation current. IFC sets lower bounds for PF and voltage unbalance ratio (VUR). The beluga whale optimization (BWO) algorithm is employed to identify the optimal operating point, addressing the lack of a unique analytical solution. Simulation and experimental results indicate that UFC reduces compensation current by 15.4% compared with FC mode. IFC achieves a 48.2% reduction.