As loads connected to active distribution network (ADN) grow, ADN’s voltage safety issues are becoming more serious. At present, the solution is mainly to build more distributed generation (DG) or to adjust the reactive power in the whole network, but the former needs a lot of investment while the latter requires a large amount of communication equipment and it takes a long time to calculate the adjustment amount of reactive power and to coordinate reactive power compensation equipment. When the loads are heavy, there will still be drawbacks of insufficient reactive power. Therefore, this paper analyzes the relationship between the active power, reactive power, and the voltage in the ADN. Through the autonomous region (AR) division, a voltage control method based on the active power variation and adjustable power in the AR is proposed. According to the relationship between the amount of active power and the adjustable amount active power, the active power control, the reactive power control, and the coordinated control of active power reactive power control are adopted to adjust the DGs’ output to stabilize the bus voltage. The simulation results show that the proposed method can effectively improve the voltage control capability of ADN and can enable it to operate normally under greater power changes. Through the control method in this paper, the communication requirements are greatly reduced and the calculation time is effectively shortened and is more adaptable.
Power and Voltage Control for Single-Phase Cascaded H-Bridge Multilevel Converters under Unbalanced Loads
