Analysis and suppression measures of lightning transient overvoltage in the signal cable of wind turbines

Abstract

Lightning strikes are a major threat to the secure operation of wind turbines. When lightning strikes a wind turbine, the lightning current flows through the blade and the tower and then the induced overvoltage will damage sensors and signal cables. In this study, a comprehensive transient surge impedance model of a wind turbine was built to analyze the causes of the overvoltage in the signal cable. The model that studies the overvoltage caused by both capacitive coupling and electromagnetic induction included the blade, nacelle, tower, signal cable, power cable, and grounding system using π networks. The influences of the cable shielding layer, soil resistivity, and lightning current waveform on the overvoltage were also analyzed. Then, 2 overvoltage suppression measures, ie, grounding at 2 ends of the outer shielding layer and installation of a surge protective device, were tested. Results show that a signal cable with double shielding layers reduced the overvoltage in the signal cable, and higher soil resistivity resulted in increased voltage on the tower base. In addition, the peak and the front time of the lightning current significantly influenced the overvoltage on the tower and the cable. The effectiveness of the 2 suppression measures was also verified. The calculation results will provide guidance for a reasonable lightning protection design.

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

“…While the overvoltage between the core and the lead sheath layer is approximately 'U‐shaped' distribution, the maximum overvoltage occurs at the top, which is close to the residual voltage of A 1 arrester. Obviously, multiple reflections of the overvoltages occur between the metal layers of the power cable, and the negative or positive reflection of overvoltage wave at the grounding or opening terminal of the power cable result in the distribution of the overvoltages between metal layers [12]. In addition, compared with the other three grounding schemes, both ends are grounded can effectively suppress the overvoltages between the metal layers of the power cable.…”

“…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. Yasuda et al studied the propagation mechanism and law of lightning surge in the wind farm system with multiple WTs when lightning strike to the blades by the digital simulator, ARENE.…”

“…In recent years, extensive research had been carried out to analyse the lightning transients in the WT through an electromagnetic transient simulation program [11–21]. 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.…”

Assessment of wind turbine transient overvoltages when struck by lightning: experimental and analytical study

“…The length (h t ) of each cylinder, as shown in Fig. 6, should satisfy the same relationship as expressed by (1). By applying the transmission-line approach to the model the WT tower, each vertical cylinder is represented by RLC π-equivalent circuit as shown in Fig.…”

“…This is why researchers attempt continuously to expand RES penetration into the electrical networks. Wind energy conversion systems, as one of the fastest growing RES (with many environmental and economic features), has been integrated either with AC grids or with DC grids [1][2][3].…”