Abstract

The analysis of lightning overvoltages generated in electrical power systems has a great meaning for the designers and exploitation engineers because it creates bases for the optimization of construction overhead transmission lines and high voltage substations, reducing costs and increasing reliability of the transmission and distribution of electrical energy. Lightning overvoltages generated in electrical power systems with overhead transmission lines are a result of complex, nonlinear, and surge phenomena occurring in the structure of line towers and electrical substation when the lightning current is flowing through them. Methods of overvoltage stress analysis are intensely developed, and one of the directions is working out models of high voltage electrical devices and phenomena in electrical networks, which influence the shape and values of overvoltage risks. The model of lightning current has a significant influence on the courses of overvoltages in high voltage transmission systems. The paper is focused on the analysis of the influence of the model of lightning current making use of simulations of the shape, and maximal values of overvoltages generated in high voltage transmission systems during a direct lightning strike to the overhead lines. Two models of lightning current used in simulations with the Electromagnetic Transients Program/Alternative Transient Program (EMTP/ATP) were analyzed, i.e., the Heidler model and CIGRE (Conseil International des Grands Réseaux Électriques) model. The EMTP/ATP computer program is very often used in simulations of overvoltages in electrical networks. Unfortunately, the users get no information on the criterion to be used when selecting the model of lightning current used in the simulations. The analysis presented in the paper gives practical knowledge about the effect of the use of a particular kind of lightning current model on the results of simulations of lightning overvoltage propagation in electrical networks, overvoltage protection, as well as on theoretical and practical aspects of the insulation coordination in high voltage transmission systems.

Highlights

  • Continuous efforts to increase the reliability of the electrical energy supply necessitate working out power systems, which should be designed, run, and maintained to minimize the probability of the system failures

  • The analysis presented in the paper gives practical knowledge about the effect of the use of a particular kind of lightning current model on the results of simulations of lightning overvoltage propagation in electrical networks, overvoltage protection, as well as on theoretical and practical aspects of the insulation coordination in high voltage transmission systems

  • Overvoltages generated with the lightning discharges to shielding wires, or phase conductors of overhead transmission lines are a result of complex, nonlinear, and surge phenomena occurring in the structure of the line conductors, towers, and electrical substation when the lightning current was flowing through them

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Summary

Introduction

Continuous efforts to increase the reliability of the electrical energy supply necessitate working out power systems, which should be designed, run, and maintained to minimize the probability of the system failures. The main part of the transmission lines stresses, defining requirements for the electrical network’s insulation and crucial for its reliable operation are overvoltages It is overvoltages generated during lightning discharges, whose maximal values may be many times higher than the network voltage, which are responsible for the basic hazard of insulation breakdown [1,2,3,4,5,6,7]. The influence of the mathematical model of lightning current on simulation of overvoltages generated in high voltage electrical network with overhead transmission lines was analyzed in the paper. The analysis gives a practical knowledge regarding the consequences of the selection of lightning current model on the results of simulations of lightning overvoltage in electrical high voltage transmission systems, the overvoltage protection, as well as on theoretical and practical aspects of the insulation coordination in high voltage electrical networks

Models of Lightning Current
Models
Modeling of Electrical Networks for the Simulation of Lightning Overvoltages
Model of Part of the Electrical Network of 220 kV Prepared in EMTP-ATP
Conclusions
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