Application of cascaded H-bridge distribution-static synchronous series compensator in electrical distribution system power flow control

In this study, the power flow control of the electrical distribution network using multilevel converter-based distribution-static synchronous series compensator is presented. The conventional radial distribution network can be changed into a meshed grid because of this device. Using multilevel converter topology, the device can be installed directly in series with the line, connecting two separate feeders from different substations together. Two control methods are proposed to control the power flow in the line. The first control strategy uses a fixed DC bus voltage. Enhancing the performance of the multilevel converter, a novel control strategy using variable DC bus voltage is introduced while maintaining the appropriate dynamic response. The new strategy can reduce the total harmonic distortion (THD) of the injected voltage and losses of the power converter compared with the fixed DC bus method. A new soft start method is also proposed to connect the separate feeders together safely. The feasibility of the control strategies is investigated through simulation and experimental results.