A Power Flow Control Measure of Across Voltage Levels Based on TCPST in a Distribution Network with DG

In recent years, Distributed Generation (DG), represented by wind power and photovoltaic, has been developing rapidly. However, the large-scale access of DG will lead to the problem of incontrollable power flow across voltage levels in medium-and-low voltage distribution networks. In this paper, we propose a power flow control measure across voltage levels in distribution based on a thyristor-controlled phase shifting transformer (TCPST). When the DG-injected power of the lower voltage network exceeds the load demand of feeders connected to DG and crosses the transformer to the upper-level network, the TCPST changes the phase of the transformer's secondary bus voltage, so that some or even all of the excess DG power could be transferred to the neighboring lines under the jurisdiction of the transformer, realizing the power flow flexible control. The mechanism of the control strategy is discussed and presented with a simplified circuit and the test is conducted on the PSCAD/EMTDC platform by building a grid-connected DG simulation model. The simulation results demonstrate that TCPST can effectively accomplish power flow control across voltage levels.