Research On The Impact Properties Of The Wind Farm Grounding Ring Network

As is acknowledged, grounding system is an vital part to ensure the safe operation of wind farms. one of the main problems threats to personal safety and equipment is a higher potential at the point of the grounding grid lightning surge current. In order to effectively reduce the impulse voltage engender by the lightning impact current, and ameliorate potential distribution of grounding grid, this paper aims to research on the impact propertities of ring ground network on wind farms.Firstly, this paper establish a ring grounding network geometry model, and then on the basis of considering the effection of high frequency of the lightning current, ignoring the resistance of the conductor, a mathematical model of rational double π-type equivalent circuit model has been established. Simulat the voltage at the point of ring ground network by ATP-EMTP, then contrast the results with the square hole grounding grids. Based on this model, analyse other factors that affect the characteristics of impact by simulation,and the simulation methods used to research optimizing means for the ring grounding network.The results showed that:impulse voltage of the ring grounding network engender by the lightning impact current just a half to the square grounding network. When the impact of the lightning current into the ground grid located at the center position of the ring, into the place at which the voltage is only about one-third is located at the edge. When lightning current amplitude increases, then the impact of the voltage at the site also will increase, and the lightning current amplitude increases, the voltage at the point of impact varies with time faster. Unequally spaced concentric rings in the impact into the ground grid voltage ratio at locations spaced concentric rings around 13.3 percent lower ground grid.On the basis of result:Compare with the square hole grounding grids, we can see that grounding ring network has better effect on the characteristics of impact, and also has obvious superiority on protection equipment and personal safety. In the ground grid design, you should try to ground deflectors arranged in the center of the ground grid to reduce the voltage at the point of impact, and should be used unequally spaced concentric rings grounding grid layout.