A Methodology to Reduce the Computational Effort in the Evaluation of the Lightning Performance of Distribution Networks

Ilaria Bendato,Massimo Brignone,Renato Procopio,Federico Delfino,Farhad Rachidi

doi:10.3390/atmos7110147

Ilaria Bendato, Massimo Brignone + Show 3 more

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https://doi.org/10.3390/atmos7110147

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Abstract

The estimation of the lightning performance of a power distribution network is of great importance to design its protection system against lightning. An accurate evaluation of the number of lightning events that can create dangerous overvoltages requires a huge computational effort, as it implies the adoption of a Monte Carlo procedure. Such a procedure consists of generating many different random lightning events and calculating the corresponding overvoltages. The paper proposes a methodology to deal with the problem in two computationally efficient ways: (i) finding out the minimum number of Monte Carlo runs that lead to reliable results; and (ii) setting up a procedure that bypasses the lightning field-to-line coupling problem for each Monte Carlo run. The proposed approach is shown to provide results consistent with existing approaches while exhibiting superior Central Processing Unit (CPU) time performances.

Highlights

Interest in the assessment of the impact lightning has on power systems is increasing in terms of power quality problems [1]
The lightning performance typically consists of curves reporting how many lightning faults per year the system may experience as a function of its insulation level; there is a probability that the line is subject to an overvoltage greater than its critical impulse flashover voltage (CFO)
Considering the limited height of distribution lines of medium- and low-voltage distribution networks, indirect lightning strikes are more frequent than direct ones

Summary

Introduction

Interest in the assessment of the impact lightning has on power systems is increasing in terms of power quality problems [1] In this respect, the evaluation of the lightning performance of distribution networks is a critical issue when dealing with the design of their lightning protection systems. The reason is that the problem of the field-to-line coupling needs to be solved a significant number of times in order to account for all of the possible values that the involved stochastic variables can assume. To face this problem, a first and simplified approach has been proposed in [2], which is based on the Rusck formula for the calculation of the maximum

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