Study on the Impact of PV Connection to Grid on Power Flow Based on Time Series Output Characteristics

PV power and other clean energy have different characteristics, including PV power is intermittent, random characteristics, unpredictable, unable to participate in the power balance. At the same time, PV power needs the support of solar radiation. The capability of PV power increases with the increase of solar radiation, so it can only generate electricity during the daytime and can not generate electricity at night, and the power generation rate in rainy and snowy days is lower. The power of PV power is greatly affected by the weather and changes faster than the normal load of the power grid. When there is cloud cover in the sky, the PV power capacity will be reduced rapidly by almost 70%. Therefore, analyzing the impact of large-scale PV grid-connected system and its countermeasures is an urgent problem to be solved in the development of PV power. Corresponding research needs to be carried out to ensure the reliable operation of large-scale grid-connected PV grid. In order to ensure the safe and stable operation of the system, the PV power station must meet the corresponding requirements in terms of power grid quality, active power control, voltage regulation, low voltage ride through, frequency stability and safety protection. Based on the influence of cloud cover and sudden changes of weather, this paper studies the situation that the output of PV power will plunge and then rise sharply, based analyzes the time series output characteristics of grid-connected PV power station. The influence of the fluctuation of grid voltage fluctuation and line load rate caused by the change of PV power on the power flow is simulated and analyzed.