2. Different grid-connected methods have different impacts. Distributed photovoltaics operating off-grid have no impact on the grid; distributed photovoltaic power generation that is connected to the grid but does not deliver power to the grid will cause voltage fluctuations; the grid-connected method of connecting to the grid and delivering power to the grid will cause voltage fluctuations and affect the relay Protected configuration.
3. Impact on power quality. The important impact of distributed photovoltaic access is to change the voltage distribution on the feeder. The magnitude of the impact is closely related to the access capacity and access location. Photovoltaic power generation is generally connected to the grid through an inverter. Frequent turn-on and turn-off of such power electronic devices are prone to harmonic pollution.
4. The impact on relay protection. Most of China's power distribution network has a single-power radial structure, and mostly adopts the form of quick-break and time-limited quick-break protection, which does not have directionality. After the distributed power supply is connected to the distribution network, its injected power will reduce the scope of relay protection and cannot reliably protect the entire line. Even when other parallel branches fail, it will cause the installation of distributed photovoltaic relay protection to malfunction.