Performance Analysis of 500 kV Transmission Lines Under Lightning Strokes Considering the Influence of Various Environmental Conditions and the Effect of Terrain Slopes in Colombia

Within the global energy transition, power system resilience has become a critical focus, especially as networks face growing demand and stricter performance requirements. In this context, transmission infrastructure plays a fundamental role in ensuring the secure and continuous delivery of electricity. Over the past decade, Colombia has advanced multiple 500 kV transmission projects to integrate the northern region’s considerable solar and wind potential with the rest of the National Interconnected System.

Despite this progress, Colombia’s unique environmental and geographical conditions pose significant challenges in the design and performance of overhead transmission lines. Lightning activity is one of the most critical factors: atmospheric discharge densities can reach 60 flashes per km² per year, with a median current of approximately 10 kA. These values differ markedly from those observed in other regions and from the assumptions commonly used in international research and standards. Combined with steep terrain, high altitudes, and spans exceeding 800 meters, these conditions substantially affect line behaviour under lightning, reducing reliability and increasing operational risk.

Measured lightning characteristics have required a redefinition of conventional analysis methodologies. Current magnitude distributions and ground flash densities must now be evaluated for each tower location, enabling more realistic performance assessments. Although international standards are followed, Colombia’s particular topography and lightning environment necessitate tailored modelling criteria and case‑specific engineering approaches.

This has led to the development of refined behaviour analyses and targeted technical solutions that can be incorporated from the conceptual engineering stage and strengthen the associated business cases.

One of the most relevant initiatives is the ITC transmission project, designed to reinforce interconnection between northern, central, and eastern Colombia by linking one of the system’s major generation plants. The project includes more than 700 km of lines—five at 500 kV and two at 230 kV—crossing mountainous regions, high-altitude plateaus nearing 3,000 meters above sea level, and savannah terrain. Additional transmission systems at both voltage levels were also analysed due to their diverse dynamic responses.

This article presents a performance assessment of transmission lines considering geographic and meteorological variables, supported by sensitivity analyses to identify the factors most strongly influencing line reliability. Finally, technical recommendations are provided to improve shielding effectiveness and enhance overall system resilience under Colombia’s demanding environmental conditions.