Systematic Design and Circuit Analysis of Lightning Impulse Voltage Generation on Low-Inductance Loads

The well-known circuit for the generation of lightning impulse voltage (LIV) on low-inductance loads was introduced by Glaninger in 1975, and the circuit component selection was proposed by Feser. However, the circuit and the approach for the component selection have some difficulties for which further adjustment is required for obtaining the waveform parameters according to the standard requirement. In this paper, an extended Glaninger’s circuit with an additional series resistor is proposed. Furthermore, a systematic design and circuit analysis of LIV generation for low-inductance loads are developed. With the help of a circuit simulator, the circuit analysis for the component selection is described. The validity of the proposed circuit was confirmed by some experimental results in comparison with the simulated ones. The proposed circuit and component selection provide not only the generation waveform according to the standard requirement but also other promising performances in terms of the wide inductance load range from 400 μH to 4 mH, a voltage efficiency of over 80%, an overshoot voltage of below 5%, an undershoot voltage of below 40%, and a maximum charging capacitance of 10 μF. From the simulated and experimental results, the proposed circuit and component selection approach is very useful for the LIV tests on low-inductance loads instead of using the conventional approach based on trial and error.

Evaluation of Surge Voltages on the Overhead Lines due to Direct and Indirect Lightning Impulse

This paper is devoted to describe how surge magnitudes are calculated and how do we use this data in order to determine the ageing of insulation on the transmission line poles so that we can replace the insulation in pre fault time, based on its condition. The main object of this report is to design algorithm of implementation of SCADA in the transmission line system to identify insulation ageing factor. In order to identify the magnitude of voltage due to direct lightning source, we have some formulae which provides the approximate value. For the magnitude value due to indirect lightning strokes, we use two methods namely RBF-FDTD method which uses artificial neural network function in order to study the detailed concept of coupling between field to transmission lines and the other method is the modelling of simulation system in which the coupling system approximations are taken. This paper also describes about the calculation of outage rate and its Geometrical analysis.