The increasing proportion of electronic devices in modern electric power systems inevitably aggravates the hazard caused by harmonics, such that the filter in electric converter substation is essential to eliminate the harmonics. In this work manta ray foraging optimization (MRFO) is employed to optimize the internal capacitance distribution of filtering equipment in the substation with renewable energy integration, which aims to reduce its unbalanced current that is created by the alerted capacitance to protect the equipment. To this end, this paper establishes the internal capacitor H-bridge model, the measured data obtained from ±500kV Yunnan Luquan Converter Station are adopted for simulation. Then, the original data are compared with the data optimized by the MRFO, genetic algorithm (GA), and particle swarm optimization (PSO) respectively. At last, it is validated that MRFO algorithm has higher convergence rate and higher quality results.