Studying the influence of electromagntiec forces on core blocks of the shunt reactors by using the analytical model and finite element approach

Abstract

The shunt reactor (SR) is widely used in  power transmission systems of 110kV, 220kV and 500kV  to absorb, balance reactive power and avoid overvoltage at the end of the line when the system is operating with no-load or low load. In order to avoid the phenomenon of circuit saturation, air gaps are often designed along the SR core to divide the large core into smaller segments (core blocks). To fix the core blocks together, the air gaps between them are inserted with non-magnetic materials (bakelite, ceramics...). However, the presence of air gaps around the core blocks will cause fringing flux and leakage flux components to link between these blocks. This makes the distribution of magnetic flux density uneven on the core blocks and will change the parameters of the SR. Due to the continuous change of the flux between the core blocks, there will be electromagnetic forces acting on the core blocks and tending to push/press them back together, causing them to vibrate, oscillate and generate noise, affecting the operation of the SR. In this study, the analytic model and finite element technique are developed to calculate the distribution of the flux around the slots/air gaps between the core blocks and the electromagnetic forces acting on the core blocks of the SR. The developed method will be applied to directly calculate a single-phase SR with a capacity of 40Mvar and a voltage of 500/√3.