基于零序电压调控的配电网不平衡过电压抑制方法

Suppression Method of Unbalanced Overvoltage in Distribution Network Based on Zero-sequence Voltage Regulation and Control

利用柔性接地装置解决配电网三相不平衡过电压问题时,常用的电流控制方法依赖对地参数及谐波电流的精确测量,应用困难。针对此,研究了不平衡过电压抑制方法中电压控制与电流控制的区别,设计了一种基于零序电压调控的不平衡过电压抑制方法。该方法在双闭环控制的基础上,采用内环比例-积分(PI)加外环一阶惯性环节的控制策略,无需测量系统对地参数及谐波电流即可实现不平衡过电压抑制,性能得到进一步提升。仿真结果证明了该方法的动态性能和稳态性能良好,能够在各种情况下准确抑制不平衡过电压。

When the flexible grounding device is used to solve the problem of three-phase unbalanced overvoltage in the distribution network,the common current control method depends on the accurate measurement of phase-to-ground insulation parameters and harmonic current,so it is difficult to be applicated.To this end,the difference between voltage control and current control of unbalanced overvoltage suppression method is studied.An unbalanced overvoltage suppression method based on zero-sequence voltage is designed.The control strategy of inner loop proportional-integral(PI)plus outer loop first-order inertial link is adopted based on double closed-loop control.This method realizes unbalanced overvoltage suppression without measuring the phase-toground insulation parameters and harmonic current,and further improves the performance.Simulation results verify the dynamic and steady-state performance of the proposed method,and show that the unbalanced overvoltage could be suppressed quickly and precisely under various conditions.