Optimal Design of Flux Coupling Differential Zero-Sequence Current Transformer

With the operation of neutral point grounding syste m with small resistance, zero sequence current transformer ha s the problems of huge volume and insufficient accuracy in pra ctical engineering. Using flux constrained zero sequence curren t transformer can solve the problem of crossing three-phase ca ble and reduce the volume of equipment. At present, the design of flux constrained zero sequence current transformer needs t o be studied. Therefore, an optimal design method of flux const rained zero sequence current transformer is proposed. Firstly, the working principle of flux constrained zero sequence curren t transformer is introduced. Secondly, the optimization directio n of flux constrained zero sequence current transformer is pro posed, and the winding method and air gap optimization desig n of flux constrained zero sequence current transformer are ca rried out aiming at accuracy. Finally, the finite element model and circuit simulation model are established for simulation cal culation, and a flux constrained zero sequence current transfor mer is developed and tested. Simulation and experimental results show that the proposed method can be used to design high-p recision flux constrained zero sequence current transformer.