Study On Lightning Protection And Grounding Of Wind Farm And Its Application In Tiantangshan Wind Farm

As an important renewable energy,wind energy plays an important role in solving the fossil energy crisis.Wit h the cont inuous development of the economy,the scale of wind farms worldwide and the installed capacit y of wind power have increased rapidly.However,due to the impact of site select ion condit ions and the construct ion environment of wind turbines,wind farms are highly likely to suffer from lightning accidents.More and more attent ion has been paid to safe operat io n during lightning strikes.Under normal circumstances,when the wind turbine encounters a lightning strike,the lightning current will be transmitted to the ent ire external tower system of the wind turbine thr ough the wind turbine blades,and then flow into the earth through the grounding device.In this process,if the wind turbine lightning protect ion grounding device is abnormal,the lightning current will seriously interfere or damage the wind turbine and its internal weak current system,and affect the stable operat ion of the wind farm and power system.Therefore,research how to improve the lightning protect ion grounding level of wind turbines to ensure The stable operat ion of wind turbines in lightning ac cidents is of great urgency and pract ical significance.This thesis first introduces the discharge process of lightning and its impact on wind turbines.Based on the simplified model of each part of the wind turbine,the lightning strike posit ion and rate of lightning on the wind turbine are analyzed,and the hazards of lightning accidents and general protect ion measures are analyzed;Combined with the mechanism of lightning current,the commo n problems in grounding technology of wind farms are analyzed,the concept of grounding resistance of wind turbines is derived,and the principles and methods of resistance reduct ion commo nly used for grounding devices are given.Based on theoret ical knowledge,the box-t ype in Hunan Tiantangshan wind farm Against the background of repeated lightning damage to the transformer,physical models of wind turbine blades,towers,control cables,box-t ype transformers and grounding devices were built,and an EMTP simulat ion model was established for ant i-realism,combined with t he lightning-related data of Hunan Power Grid and field measurement of wind turbines.The nearby soil resist ivit y,grounding impedance and the integrit y of grounding devices are analyzed,and the operat ion mode of lightning current in wind turbine generators and transformer units is analyzed.Finally,the influence of wind turbine layout and different lightning strike posit ions on overvoltage distribut ion is analyzed.Through the simulat ion analysis of the lightning transient overvoltage of the wind farm,we can understand the impact of lightning strikes on the various electrical equipment of the wind farm,propose solut ions,provide a reference for the construct ion of the project,and reduce the economic loss of the wind farm caused by the lightning disaster.