Multi‐objective optimal design for AC filters in high voltage direct current system based on improved multi‐objective evolutionary algorithm based on decomposition

A triple‐objective optimal design method for AC filters in high voltage direct current (HVDC) system based on an improved multi‐objective evolutionary algorithm based on decomposition (MOEA/D) is proposed. A triple‐objective optimisation mathematical model including total harmonic distortion (THD) on AC side voltage, investment cost of AC filters and telephone harmonic form factor (THFF) is established. An improved MOEA/D is proposed to realise the triple‐objective optimal design for AC filters more efficiently. The improved MOEA/D adds a particular mutation operator, which can not only to prevent MOEA/D from getting stuck at local optimum but also accelerate the convergence to the optimum solution while the algorithm approaches the neighbourhood of the optimum solution. A three‐dimensional fuzzy evaluation system is designed to select the optimum solution of the triple‐objective optimisation. A case of ±500 kV HVDC system is simulated. Taking the ±500 kV HVDC system as the prototype system, a dynamic simulation experimental platform of the rectification system of the direct current transmission system with AC filters is designed and established based on the similarity principle. Both the simulation and experimental results verify that the proposed method have excellent performance.