Assessment of the hazard risks on HVDC transmission networks due to lightning strikes and faults.

HVDC systems with high voltage and direct current are suitable for reducing electricity losses, during transmission over long distances. However, HVDC lines have the highest probability of failure within a system and can be damaged by different faults or lightning strikes. This paper presents a transient circuit model for the practical Egypt-Saudi Arabia link. The transient potential at different points along the line is calculated under different magnitudes and shapes of lightning strokes. "Additionally, the extent of transient overvoltages at the rectifier station due to shifts in lightning strike locations has been estimated. Furthermore, overvoltage distributions are examined caused by lightning strikes on a real ± 500 kV hybrid HVDC TL-Cableare examined. To prevent national disasters and maintain safe national ratios of electrical production, particularly in the case of hybrid HVDC TL-Cable faults, an analysis of different AC/DC faults in the hybrid HVDC TL-Cable is also presented. This study is based on an equivalent electrical model using Power Systems Computer-Aided Design (PSCAD) software. It was discovered that severe voltages appear at the rectifier station when 50 kAlightning stroke with 1.2 μ sec front time, and 350 μ sectail time hits the TL. Moreover, overvoltages are reduced by about 58% in hybrid HVDC TL-Cable. Also, surge arresters at rectifier stations reduce overvoltages by approximately 95%. Ultimately, DC pole-to-ground faults are more serious than other types of faults and can cause massive overcurrent in the system, potentially damaging the rectifier station.