Improving Power Quality by a 10 / 20 kV / 0.4 kV Voltage Regulated Distribution Transformer using Semiconductor Switching Devices

摘要

Future distribution grids will have to handle new requirements like bidirectional power flow due to distributed generation within the voltage levels and over transformation levels. One promising solution to improve power quality in such cases is the use of voltage regulated distribution transformers (VRDT). This paper summarizes technical requirements that were the basis for the development of a 10 kV-VRDT. Semiconductor switches are used to vary the voltage on LV side by switching transformer taps on the HV side of the transformer. Experiences with some 10 kV-VRDTs proved that the VRDT fulfils the requirements and prevents violations of the voltage band. This paper introduces an optimized VRDT that was developed on the basis of these experiences and that is able to handle 20 kV on the HV side as well as 10 kV.