Research On Strategy And System Of Anti-islanding For Photovoltaic Power Station

With the development of photovoltaic power generation,the size and number of photovoltaic power generation system is gradually increased,especially large-scale photovoltaic power plants,power line access is increasing.Especially the centralized photovoltaic power station,when the fault occurs,photovoltaic power plants will run in the state of island.In this case,due to power off and reference voltage and frequency lost in the island,there will be greater volatility and damage to the power grid and user equipment.When the power supply recovers,the output voltage phase of the power generation system may not synchronize with the power grid,causing a large current impact,damaging the photovoltaic power generation equipment and load side equipment,and even lead to the power grid re trip.Therefore,it is of great practical significance to study the fast and reliable islanding protection methods and protection measures for the PV power plants on the side of the system.Based on the actual situation of Yancheng Power Grid,the following research work is carried out:Firstly,the current application status and Prospect of photovoltaic power generation are analyzed,and the significance of photovoltaic anti islanding strategy is discussed.A large number of literature analysis and research are carried out,and the research status of photovoltaic island detection technology and anti islanding strategy is analyzed.Secondly,the development status and future planning analysis of centralized photovoltaic power station in Yancheng Power Grid are carried out.And in the background of high permeability of Yancheng power grid photovoltaic power generation,safety and stability of Yancheng power grid photovoltaic power generation are analyzed,and the safety and stability of the possible problems and solutions are put forward.Third,islanding detection technology is studied,and three kind of commonly used active detection method are introduced.An improved power perturbation method based on fuzzy control technology was put forward,which reduces the intensity ofdisturbance of the system,improves the ability to prevent false island protection at the same time,and makes the island detection performance more efficiency.Finally,the software platform of PV anti islanding system is designed,and the anti-islanding stability device is researched from five aspects,including hardware configuration,working principle,electrical quantity measurement,device starting condition and fault type criterion.PV anti islanding system is built on the basis of software platform and anti-islanding stability device.Taking 110 kV Yilin substation of Yancheng Power Supply Company as an example,the action process and mechanism of anti-islanding stability device were analyzed,which verifies the validity and reliability of the anti-islandinging system.