A New Grounding Resistance Reduction Method for Wind Turbines by Grounding Grid Connection in Limited Areas

Abstract

Restricted by cultivated land vegetation, road construction, and land acquisition compensation costs, the grounding electrode extension method is not applicable for grounding resistance reduction of some wind turbines in limited areas. A new grounding resistance reduction method is proposed and verified for wind turbines by connecting nearby wind turbine grounding grids. To study the efficiency of the proposed method, the grounding characteristics of connected grounding grids are calculated. Simulation results indicate that the grounding resistance of connected grounding grids is smaller than that of box extension grounding grids. The grounding characteristics of the grounding grid connection are affected by grounding current frequency and material parameters. The grounding grid connection increases the current dispersion area and reduces the ground potential rise of the grounding conductor.

Mechanism Analysis and Multiphysics Validation of Lightning Attenuation in Constrained Space

“…It is assumed that the arc conductivity σ A remains constant during the expansion of the arc channel, the arc channel radius expression can be derived as Equation ( 9) [11], [12]:…”

“…where arc conductivity σ A = 30000 S/m; gas initial density ρ 0 = 2.97 kg/m 3 . Besides, the impulse arc current during wave-front time can also be written as (Equation ( 11)): (11) The relationship between the wavefront time and wavefront time constant is Equation ( 12):…”

“…Taking Equation (11) and Equation ( 12) into Equation ( 10), and taking the result into Equation (4), the lightning arc impact overpressure curve is plotted. The different current lightning discharge overpressure curve under natural condition is shown in Figure 3.…”

“…where i is the arc current, and r is arc radius. Substituting Equation (11) into Equation ( 29), the arc axial truncation pressure can be obtained as a new equation, Equations (30):…”

“…Hence, the grounding grid resistance must be restricted to lower levels. But it is restricted by cultivated land vegetation, road construction, and land acquisition compensation costs, the grounding electrode extension method is not applicable for grounding resistance reduction [11]. Besides, in order to reduce the grounding resistance, researchers have taken a series of measures, including increasing the depth of buried ground network, deep well grounding, local soil replacement and other technologies, but it is difficult to achieve the requirements of grounding resistance [8], [12], [13], [14], [15].…”