光伏电源的PQ耦合潮流模型及对配电网电压的影响

Power Flow Calculation Model of PQ Coupling Photovoltaic and Influence of Photovoltaic on Distribution Network Voltage

光伏电源并入配电网络,不仅充当着有功电源,还可适当输出无功功率,承担调节电压的重要作用。根据并网光伏电源的结构,建立了光伏电源PQ耦合的潮流计算模型,其有功与无功输出均与逆变器的调制比和移相角密切相关。根据实际系统对光伏电源的需求设置调制比和移相角,使逆变器既能工作于合理状态,同时也能满足系统功率需求。光伏电源并入配电网,其有功和无功输出共同影响配电网电压,算例表明PV型光伏电源对局部节点电压提升效果显著,PQ耦合且具有最大电压调节能力的光伏电源对系统整体电压提升效果显著。

Photovoltaic power incorporated into distribution network provides the active power. At the same time reactive power output is very important in regulating voltage. According to the structure of grid-connected photovoltaic power, the power flow calculation model of PQ-coupled photovoltaic power is established. The active and reac- tive power output of photovoltaic power is modulated by phase shift angle and modulation ratio of the inverter. According to the actual output need of photovoltaic power, setting the modulation ratio and phase shift angle, inverters can work at a reasonable state and the output of photovoltaic power can also meet the system power requirements. The active and reactive power output of grid-connected photovoltaic power affect the voltage of the distribution network. Numerical examples show that the PV type photovoltaic power approves the local node voltage significantly, PQ coupling and with a maximum capacity of voltage regulator type photovoltaic power approves the overall system voltage significantly.