An Arcless Step Voltage Regulator Based on Series-Connected Converter for Branch Current Suppression

With more distributed power generation and renewable energy penetration, voltage fluctuation and power generation variation can be observed more frequently in the modern power distribution network. More tap change operations are required for the step voltage regulator (SVR) to regulate the line voltage. However, the tap changing mechanism of the conventional SVR always generates an electric arc when tap changes, which imposes constraints on conventional SVRs, such as lifetime and maintenance period. This article proposed a new topology of arcless step voltage regulator based on a series-connected converter for current suppression. The system efficiency is the same as the conventional SVR in the normal operation, while the converter power rating is only 0.3% of the total system power. A scaled-down prototype of the arcless SVR is developed to verify the proposed arcless tap changing method. The hardware test results verified that the proposed arcless step voltage regulator can eliminate arcing during the tap change and reduce the contact erosion rate by over 10000 times the conventional arcing SVR. Other advantages of the novel method over the conventional SVR, such as advanced load voltage regulation and volt/var control, are also verified.