The significance of median natural lightning current strokes on the energy handling capabilities of surge arresters employed in wind farms

Abstract

a b s t r a c tThe significance of the median natural lightning currents on the energy handling capabilities of surge arresters employed in wind farms is investigated. The Electromagnetic Transient Program Alternative Transient Program (EMTP-ATP) was used to simulate direct lightning strikes to the blade of an existing wind turbine in order to determine the current discharged through the surge arresters and hence the energy absorbed by the surge arresters located at different wind turbines. The values of the energy handling capabilities of surge arresters are generally published in manufacturers' datasheets. Yet, the impact of the subsequent lightning strokes is usually ignored. Also, the published energy handling capabilities are based solely on standard waveforms. This contribution uses two sets of natural lightning current parameters measured on instrumented towers at Mount San Salvatore and Morro do Cachimbo, to simulate lightning strikes to the wind turbine blade. The results show that the influence of the subsequent strokes can be significant for the current discharged through the surge arresters and the subsequent energy absorbed, especially at the stricken turbine.

The impact of lightning strike to multi‐blade on the lightning overvoltage and stresses of arresters in offshore wind farm

“…In recent years, extensive research had been carried out to analyse the lightning transients in the WT through an electromagnetic transient simulation program [11][12][13][14][15][16][17][18][19][20][21]. The authors of [11,12] aimed at the low-voltage control system with the largest damage probability of a lightning strike to the WT, the influences of lightning overvoltages on the control cable in the WT were simulated and analysed, and the corresponding lightning protection measures were proposed.…”

“…Moreover, the influences of grounding of the metallic sheath of the cable and grounding resistance on the lightning overvoltages in underground cables of the collector system when direct lightning strikes to the wind power generation system were discussed in [15]. In [16,17], the overall structure of the WT and tower were modelled as a lossless conical and cylindrical transmission line with constant parameters; then, the impact of multiple lightning flashes and the median lightning currents on the absorbed energy by surge arresters is investigated. However, in the analysis of the electromagnetic transient simulation of WTs in [13][14][15][16][17], the tower was equivalent to the lumped inductance or wave impedance model, or the influence of electromagnetic coupling between the tower and power cable is not considered.…”

“…In [16,17], the overall structure of the WT and tower were modelled as a lossless conical and cylindrical transmission line with constant parameters; then, the impact of multiple lightning flashes and the median lightning currents on the absorbed energy by surge arresters is investigated. However, in the analysis of the electromagnetic transient simulation of WTs in [13][14][15][16][17], the tower was equivalent to the lumped inductance or wave impedance model, or the influence of electromagnetic coupling between the tower and power cable is not considered. It is pointed out that the rapid magnetic field changes caused by lightning current, and the distributed capacitance between the control line and tower results in higher induced voltage in control line in [11,12].…”

“…FIGURE17 Maximum overvoltage between the tower and the steel armour layer with different lightning currents for lightning strike to double blades…”