WU Xiaofei，DAI Hui，HUANG Xiaojian，YANG Meng，LIU Haoming
With large-scale photovoltaic （PV） systems access to distribution network， a coordinated voltage control strategy considering PV converter's reactive power for distribution network with multiple voltage levels is proposed， which aiming at the problem that low-voltage distributed PV's reactive power is not fully utilized and reactive power and voltage in high and low voltage distribution network are not coordinated and optimized as a whole. In the low-voltage distribution network where communication network is not available and unable to achieve unified scheduling， three kinds of local autonomous voltage control modes are chosen to control the reactive power and voltage in real time. In the proposed reactive power and voltage coordinated control model for distribution network with multiple voltage levels， considering a variety of reactive power sources including PV inverters with communication networks， models for voltage partition and dominant node selection are established， and a two-layer coordination control strategy， including the upper global optimization and the lower subdivision optimization， is designed. This strategy fully mines the capability of PV converter's reactive power to adjust the voltage of the distribution network， and realizes the accurate control of reactive power and voltage. A practical example system， the distribution network supplied by Shuanglong 220 kV substation in Jiangsu Province， is used to verify the proposed strategy， and the results verify its advantages in reactive power and voltage control as well as the ability of accessing PV power.
