主动配电网多级无功电压协调控制研究

分布式光伏大量接入配电网后电压越限问题成为影响电网安全稳定运行的关键因素。为了适应高渗透率、大规模分布式光伏的接入,提高系统调压能力,本文依据主动配电网内调压资源特性的不同,对其进行了分类分级处理,提出了主动配电网多级无功电压控制策略,即分别利用小容量分布式光伏、光伏电站无功、传统VQC装置和光伏电站有功实现系统一、二、三、四级调压。其中,针对小容量分布式光伏所采用的分散式就地控制策略,提出了基于并网点电压和光伏实际有功出力的cosφ(U、P)控制模型。最后,基于改进的IEEE33节点算例进行了仿真,仿真结果表明本文所提出的四级调压策略,充分利用了主动配电网内分散的调压资源,有效减少了VQC装置动作次数,并改善了配电网电压水平。

Research on Multilevel Reactive Power and Voltage Control of Active Distribution Networks

With the access of large amount of distributed PVs to the distribution network, the overvoltage becomes the key factor that affects the operation security and stability of power grid. In order to adapt to the high permeability and large-scale access of distributed PVs to power grid, and to improve voltage regulating ability of system, a multilevel reactive power and voltage control strategy for active distribution network is proposed by classification according to the different characteristics of the voltage resources in the active distribution network. The proposed control strategy can achieve the first, second, third and fourth-level voltage regulation based on small-capacity distributed PV, reactive power of PV, traditional VQC device and active power of PV. The decentralized local control strategy is applied to control small-capacity distributed PV, by which the control model of cosφ(U、P) is proposed based on voltage and PV active power output. In the end, taking the modified IEEE33-bus system as example, the simulation result shows that the proposed four-level voltage regulation strategy makes full use of distributed voltage resources in the active distribution network, action times of the VQC device is reduced effectively, and the voltage level of network is improved.