A new type of closed-type Lightning protection multi-chamber arrester named impulse quenching line Lightning protection device (LLPD) used for protection of overhead power lines is described. After the passing of Lightning current, the multi-chamber system of the arrester prevents the occurrence of a network short-circuit current due to the total voltage drop across several thousand series-connected spark gaps that significantly exceeds the applied network voltage in magnitude. The total operating time of the LLPD is less than 1 ms which is not sensitive for microprocessor and relay protection of overhead lines. A computational estimation of the emergency outage rate of double-circuit overhead power lines without an overhead ground wire resulting from Lightning overvoltage was carried out. Number of current impulses used when arresters are tested for quenching capacity as well as their parameters were determined by the mathematical modeling using the statistical Monte Carlo method. Results of calculation that make it possible to determine the efficiency of Lightning protection of double-circuit overhead lines with various placement schemes of the line Lightning protection device LLPD-110 of the company Streamer Electric AG are presented in the conclusion.

This paper presents a new method for proper modeling of time domain multi-ports grounding systems that can be implemented in transient state-of-the-art analysis software. The presented method aims in minimizing the approximation in the frequency modeling of grounding systems in the transient analysis of power systems. The proposed solution is divided into three stages: First, the use of an electromagnetic method for solving the Maxwell equations, which leads to the extraction of the impedance matrix of the grounding system in a desired frequency range. In the next step, a logical approximation of the impedance matrix was made using the Vector Fitting (VF) method. The used VF method has led to the fitting of a set of poles for all impedance matrix arrays. In the final stage, considering that all the transient soft wares analyze power systems based on the admittance matrix, the proper model of the time domain multi-ports grounding system is executed by state space equations. The proposed modeling is performed on a typical 132 kV transmission line, and Performance of implemented grounding system is compared with the previous methods including admittance matrix modeling and conventional model based on simple linear resistances.

Direct Lightning strokes to launch pad damage some vital instruments. Thus, the Lightning protection system is used to protect instruments. Calculating the probability of direct Lightning strokes is the main consideration in Lightning protection system design, however this calculation is not simple since the shape of launch pad is complex. In this paper, a 3-D numerical analysis model based on Leader Progression Model (LPM) is proposed to calculate the probability of direct Lightning strokes to launch pads. The progression of Lightning downward leader, the inception and propagation of upward leaders are modeled step by step until final jump. Launch pad, Lightning protection system, downward and upward leaders are modeled by different shapes of charges, and the environment electric field is computed using charge simulation method. Then, Lightning Performance of two actual launch pads are evaluated, and the simulation results are compared. Finally, the high voltage laboratory tests have been achived to validate the proposed protection system design.

Lightning strikes that directly hit the wind turbine will probably attach to the blade could cause excess structural damage. The blade and hub usually represent around one fourth of the cost of a large modern machine and may be the most expensive components to replace. The blade is not only the link between wind energy and the mechanical energy going to the gearbox, but could be a Lightning link to all the equipment associated with the wind turbine. In this paper a model of Lightning channel progression towards the earth is given based on physics of discharge of cloud. The physical assessment of the electric field is done with the charge simulation method which is adopted to describe into MATLAB software the parameters which are involved in the progression of the negative downward channels towards the earth and in the inception and propagation of upward positive channels from earthed structures. The method and results can be used for designing Lightning protection system of wind turbine.

The produced electric and magnetic fields due to Lightning strikes to mountainous ground are determined in this paper. For the sake of simplicity a cone-shaped ground with finite conductivity is assumed to represent a natural nonflat ground. By this assumption, we deal with an axillary symmetrical structure so we use the cylindrical 2D-FDTD to save the simulation memory and time, dramatically. The return stroke channel is modeled using the antenna theory model with fixed inductive loading (ATIL-F) which is appropriately incorporated into the FDTD algorithm. We have derived the updating equations of 2D-FDTD for distributed resistance and inductance in ATIL-F model. Both the first and the subsequent return strokes are considered and their related radiated electromagnetic fields are determined and compared with each other. The fields are calculated at an intermediate horizontal distance from the cone-axis.The calculated results show that the presence of the cone-shape ground introduces an enhancement in electric and magnetic fields, for both first and subsequent return strokes. Since sharper lossy cone means larger current density in the ground, the increment in the amplitude of the fields is inversely proportional to the cone-angle. A hump is observed in electromagnetic field waveforms because of the current reflection form joint point of the cone-shape ground and the flat ground beneath it. It is more specific in the subsequent-stroke fields. simulation results for different cone-height are presented. It shows that for small values of height, the results approaches to thoseof the flat ground.

Lightning is the main factor of outage and insulation breakdown of power system. The Lightning event can produce dangerous overvoltage, equipment failures, and power supply interruption. In this paper, externally gapped Line arresters (EGLAs) Performances have been investigated to evaluate the Lightning Performances of a typical 63 kV transmission line. A probabilistic analysis has been done to study the EGLA Performance in transmission line by Monte-Carlo method. The results show the EGLA Performance dependency to soil resistivity and Lightning strike parameters.