Analysis of UHV Shunt Reactor Operation

The operation practice of AC UHV transmission project for more than ten years shows that it is difficult to develop UHV shunt reactors; The experience in the development, operation and maintenance of conventional voltage grade reactors is not enough to completely solve the problems faced by UHV shunt reactors. In this paper, the internal potential distribution of UHV shunt reactor under transient overvoltage is simulated and measured. The research results show that for the body structure composed of double coils, under the transient overvoltage with wavefront time of 100~200 μ s, there is potential oscillation phenomenon on the inter-column connection, which will cause the potential difference between the end of the reactor coil to ground, the middle of the coil and the end of the coil to become larger, and there is a risk of reducing the insulation margin of the equipment. Combined with the structural characteristics of the reactor, the weak links exposed by previous equipment failures, the operating location and the changes of overvoltage levels before and after the expansion of UHV substation, the operation risks faced by UHV shunt reactors under the transient overvoltage invading along transmission line when the line is struck by lightning are analyzed, and the possible causes of equipment failure caused by lightning strikes on the line under the joint action of multiple factors are proposed. It is proposed that the check analysis under transient overvoltage at different frequencies should be added in the development of UHV shunt reactors. In terms of operation and maintenance, attention should be paid to the change of particle size in oil. Finally, the necessity of analyzing the flow, distribution and local accumulation of particles in the oil (liquid) of UHV shunt reactors under self-cooling conditions is discussed.