Loss Reduction in Gapped-Core-Type Shunt Reactors via Magnetic-Flux-Distribution Improvement

With the steadily increasing number of systems utilizing ultrahigh-voltage transmission lines, such as 765 kV and 400 kV substations, shunt reactors have come under the spotlight as a viable option to increase the load capacity and reduce losses. However, the cumulative losses during their operational life increase. In this study, we improved the magnetic flux of a yoke and analyzed its effect on loss reduction in the iron core. We applied a magnetic flux control structure that equalized the main and leakage fluxes generated from the main leg of a gapped core-type shunt reactor with the leakage flux generated from the winding. The magnetic flux generated by the yoke and its distribution in the in-plane direction with and without the flux-control plate were analyzed and compared using Maxwell’s three-dimensional finite element method. We evaluated the losses exhibited by two fabricated shunt reactors with a sensor installed on their iron cores to verify the effectiveness of improving the magnetic flux distribution of shunt reactors. The results confirmed that the magnetic flux control plate reduced the iron and winding eddy-current losses in the gapped core-type shunt reactor. Further investigations are required to minimize loss and noise throughout the operational lifespan of these reactors as well as to decrease the size and weight of shunt reactors for different applications.