Computation of Electromagnetic Parameters of Shunt Reactors Taken Corner Chamfers of Core Block into Account

Abstract

The shunt reactor (SR) is applied in electrical systems to avoid the overvoltage and absorb the reactive power in transmission lines under operation with no or low load conditions. To avoid magnetic saturation, an air gap is designed at the middle of core of SR. However, the size and shape of air gap will influence directly in the distribution of leakage and fringing fluxes. This leads to uneven distribution of flux density in the SR core and generate electromagnetic forces (EMF) acting on the core and windings of the SR. The electromagnetic forces tend to push/compress the SR core with the different directions, causing oscillation, vibration, and generating audible noise, affecting the operation of the SR. Recently, many papers have studied the SR with one or several air gaps. For the one air gap, it usually has a large size, which leads to a significant leakage and fringing fluxes. In the case of multiple air gaps, the leakage and fringing fluxes will be smaller, leading to reduction of the EMF acting on the core blocks of SR. However, the use of multiple air gaps will encounter technological difficulties.
In this paper, the corner chamfer of SR core is proposed to investigate the distribution of magnetic fields along the core block and EMF acting on the core, as well. This development is performed with two processes: an analytical model is first presented to define main parameters of SR, then a finite element method is applied to calculate and simulate the electromagnetic parameters such as magnetic fields and electromagnetic forces of the SR. The presented method will be validated on a practical single-phase SR