光伏光照概率性对配电网电压的影响

Influence of Illumination Probability of Photovoltaic System on Voltage of Power Distribution Networks

分布式光伏发电接入配电网后将对配网无功电压特性产生诸多影响.文中建立了基于太阳辐射度Beta分布的分布式光伏发电系统概率模型,考虑太阳辐射度对光伏发电系统出力的影响,模拟了晴天少云、晴朗无云、晴间多云这3种典型天气情况下光伏发电系统的出力变动,得到连续时间断面的概率性光伏出力,依次进行潮流计算,并与恒功率光伏电源模型的潮流计算结果作对比.结合算例仿真,总结分析了光伏并网后对配电网稳态电压分布和电压幅值波动的影响规律,并验证了概率性分布式光伏发电模型相比于传统的恒功率模型更能够反映光伏电源出力的波动性和随机性.

In order to explore the reactive voltage characteristics of power distribution networks affected by the grid- connected photovoltaic （PV） system, a probabilistic distribution model of PV power generation system is estab- lished based on the Beta-distribution of solar irradiance. Then, by of solar radiance on the output of PV power generation system, the taking into consideration the probabilistic impact PV outputs in three typical weather conditions, namely a low cloudiness day, a cloudless day and a partly cloudy day, are simulated, and the probabilistic output of PV power generation system in continuous time sections is obtained, which is used to perform the power flow cal- culation in turn. Moreover, the calculated power flow is compared with that obtained by using the constant power model. Finally, an example is given to analyze the laws of voltage distribution and voltage amplitude fluctuation in grid-connected PV distribution networks. The results also show that, as compared with the conventional constant power model, the established probabilistic model reflects the randomness and volatility of PV output better.