Solid state transformer for connecting consumers to the medium voltage network

Abstract

In this paper the authors describe and analyze an innovative solution for the development of an electronic transformer (Solid State Transformer-SST) with the voltage 10.0/0.230 kV. The transformer is designed to provide direct power to low-voltage consumers from the medium voltage network with the 50 Hz frequency. The proposed transformer permits bidirectional energy exchange. In order to stabilize the low voltage output, an original method has been adopted to manage the parameters of the control pulses for the transistors of the SST inverter. The primary winding of the high frequency transformer consists of 16 coils connected separately by means of two transistors. The design simplification of the transformer leads to the increase of energy efficiency indicators of the transformer and helps to reduce the high harmonics of the voltage and current in the power distribution network with a positive impact on power quality. It becomes possible to use this equipment to connect renewable energy sources, for example, the so-called micro-grids, to centralized power network of medium voltage.