含高比例光伏的配电网电压协调控制策略研究

Research on Coordinated Distribution Network Voltage Control Strategy with High Proportion Photovoltaics

随着分布式光伏大量接入,电压波动问题严重威胁着配电网安全稳定运行。为了改善高渗透率光伏并网后的配电网电压水平,提升系统的调压能力,提出了一种含高比例光伏的配电网电压协调控制策略。该策略通过协调光伏有功和无功,以及变压器OLTC实现配电网的电压协调控制。对光伏出力比较大的高、中压配电网,使用基于PI控制器的有功控制;对于光伏出力较小的低压配电网,采用无功控制方法保证母线电压处于允许偏移范围;此外,将调整OLTC的分接头作为一种后备调节方式。算例的仿真结果验证了所提控制策略可以明显改善配电网电压水平。

With the massive access of distributed photovoltaics, voltage fluctuations seriously threaten the safe and stable operation of distribution networks. In order to improve the voltage level of the distribution network with integration of high-permeability photovoltaics and enhance the voltage regulation capability of the system,a coordinated voltage control strategy for the distribution network with high proportion photovoltaics is proposed. This strategy coordinates the active and reactive power of photovoltaics, and the transformer OLTC to realize the coordinated voltage control of the distribution network. For high-voltage and medium-voltage distribution networks with large photovoltaics output, active control based on PI controllers is used; for low-voltage distribution networks with small photovoltaics output, reactive power control methods are used to ensure that the bus voltage is within the allowable offset range; besides, OLTC tap adjustment is taken as a backup adjustment method. The simulation results of the example verify that the proposed control strategy can significantly improve the voltage level of the distribution network.