Research On Magnetic Shielding Measures And Structure Optimization Of Air-core Reactor Used In SVC

The security and stability operation of power grid has relation to the balance of reactive power. Traditional reactive power compensation device can hardly meet the dynamic balance of reactive power. SVC dynamic compensation device has the ability of fast balance of load reactive power, significantly improve the power quality as well as the operation efficiency. Therefore, more and more SVC applied in the system. In order to guarantee better linearity in adjustment progress, air-core reactors are used in the SVC systems. But there is a problem in the application of SVC system that is the strong space magnetic field due to no iron core to form closed magnetic circuit. The strong magnetic field of the air-core reactor will affect adjacent equipment, for example cable, which endangers the security operation of the equipment around and systems. Besides, the strong magnetic field may does harm to the workers exposed to it. In consideration of a large number of air-core reactors used in power system, research on shielding method of magnetic field has important application value.In the paper,calculation of air-core reactor magnetic field is studied,which is based on the study about theory of numerical calculation of electromagnetic field. Simulation analysis of air-core reactor with different structures is also done. In order to shield space magnetic field of air-core reactor, two shielding methods, shielding plate and shielding cover, are used. Based on a large number of numerical calculations and field tests, this paper introduces comparative analysis about space magnetic field before and after a shielding plate is set at the end portion of single-phase reactor. It gives the optimal setting plan after researches on meterial, location and size of shielding plate are carried out.It shows that the shielding effect of aluminum is better than steel. Then, this paper carries out calculation and test analysis about setting shielding cover aorund single-phase and three-phase reactor. In the course of these analyzes about setting shielding plate and shielding cover, influence the shield may has on the reactor is taken into accout, such as current distribution, loss and equivalent inductance changes. It proposes technical solution that aims at compensate the change of current in the encapsulation caused by setting shielding cover by adjusting turns of the reactor winding.This paper provides some suggestions about practical engineering application.