Reactive Power Dynamic Allocation Considering Multiple Wind Farms Voltage Regulation Diversity

In the secondary voltage control, the wind farm realizes voltage control by adjusting the reactive power. Within an adjusting cycle, the wind farm substation changes its reactive power output through droop control. Adjusting cycles of substations are different, thus the adjustments of substations is out of sync. In the dynamic process of substation voltage adjustment, the variation of reactive power output of one substation will affect the voltage of other substations, thereby affecting the reactive power output of other substations. It is generally required that the substations in the area decide the reactive power output value according to the electrical distance between them so as to achieve an optimal balance of reactive power with minimal cost. This paper proposes two indexes to evaluate the imbalance of reactive power allocation and then explores the elements that affect the balance of regional reactive power through simulation. Results show that the different regulating cycle of substations will lead to the imbalance of reactive power allocation. Substations with short voltage regulating cycle need to output more reactive power. And the imbalance level of reactive power allocation over substations can be mitigated by reducing the droop coefficient.