Modelling and analysis of direct and indirect interactions of lightning electromagnetic pulse with high voltage lines

High voltage energy facilities and transmission lines, critical elements of power systems, are prone to serious faults and harmonic distortions due to lightning electromagnetic pulses (LEMP). These faults lead to disruptions in energy consumption and economic losses, necessitating the implementation of preventive measures. In this context, the modelling and analysis of high voltage (HV) systems using simulation programs such as MATLAB, EMTP and CDEGS are of paramount importance in determining the necessary measures to be taken. The aim of this study is to analyse electrical faults caused by LEMP in energy transmission lines and associated facilities using simulation programs and to minimize the effects of these faults. Despite existing studies in the international literature, comprehensive research at the national level is insufficient. The originality of this study focuses on the development of new protection strategies using electromagnetic screening methods, in addition to classical protective measures (surge arresters and lightning rods). Electromagnetic compatibility (EMC) screening methods have been proposed to minimize the direct and indirect effects (coupling effect) of LEMP. In this context, the analysis of faults caused by LEMP in energy transmission lines and associated facilities, determination of the locations of these faults, and minimization of their effects are targeted. Simple and practical mathematical models for solving faults caused by LEMP have been developed based on analytical methods and simulations using real-world data. These models significantly facilitate the resolution of faults caused by LEMP in the national grid. Analytical calculations have been conducted on energy transmission lines with intense lightning strikes in the Western Mediterranean and Aegean regions of Turkey, and real-time data has been obtained from the Turkish State Meteorological Service and the Turkish Electricity Transmission Corporation. Cable and overhead lines of 380 kV, 154 kV, and 34.5 kV used in Turkey have been examined, different pole types have been evaluated, and analytical calculations and software developments have been made in various regions, especially Antalya, Burdur, Isparta, Mugla, and Denizli. These data include the lightning characteristics of the lines and facilities, grounding, and protection conductor properties. The analysis of faults caused by LEMP and coupling effects has been carried out using mathematical models and computer simulations, and new protection methods have been proposed. Additionally, a new perspective on the grounding structure of pole towers has been provided, and grounding models in the form of Faraday cages have been created and compared with traditional grounding models. While the international literature has generally focused on situations resulting from direct lightning strikes on the line, this study comprehensively addresses indirect strikes as well. Furthermore, the benefits of using surge arresters to improve the performance of energy facilities and transmission lines against LEMP have been examined. EMTP-ATP simulation analyses have been conducted to determine the optimal and cost-effective placement of surge arresters, and different configurations have been evaluated. Two different designs have been considered to protect transmission lines from LEMP: installing line surge arresters on selected phases of each tower and installing line surge arresters on all phases of selected towers. Different surge arrester installation configurations have been evaluated using the flashover values of line insulators as threshold voltages. Additionally, the characteristic impedance of the lines has been examined in terms of LEMP performance, and it has been suggested that attention should be paid not only to the grounding resistance but also to the characteristic impedance of the line. This thesis aims to determine the effect of LEMP on parameters such as ground conditions, grounding design, and the location of LEMP current injection through simulation and numerical methods. Real-time transient analyses have been performed using MATLAB/Simulink and EMTP-ATP simulation programs with data obtained from the Turkish Electricity Transmission Corporation and the State Meteorological Service. The study has facilitated the development of simple and practical mathematical models for solving faults caused by LEMP in the national grid. In conclusion, it is expected that the simulation models obtained because of LEMP analysis will contribute to developing artificial intelligence-based network studies. In this context, the results obtained significantly contribute to the national and international literature and lay the foundation for further research.