HVDC–HVAC Hybrid Lines: A Feasible Solution for Transmission Expansion in Colombia

Hybrid HVDC-HVAC (high-voltage direct current and alternating current) transmission corridors are being considered as an option to increase the power-transfer capability of existing rights-of-way, reducing the need for new infrastructure and limiting additional environmental impact.

This strategy uses a common corridor for both systems, either by adding an HVDC circuit to an existing HVAC line or by converting an HVAC line to HVDC. While this increases capacity and operational flexibility, the physical and electrical coexistence of AC and DC conductors gives rise to electromagnetic coupling phenomena (capacitive and inductive coupling, modified electric fields, corona, audible noise, and radio interference) that must be quantified and controlled to ensure operational safety and compliance with environmental and regulatory requirements.

This paper evaluates the technical feasibility of HVDC–HVAC corridors in the Colombian transmission system, focusing on electric field limits, design, and electromagnetic compatibility. The study applies a sequential methodology to a representative 500 kV corridor and shows that hybridization is technically feasible and potentially cost-effective, particularly in areas where conventional expansion is constrained. Based on the results, key technical requirements and elements of a roadmap for the sustainable implementation of hybrid corridors in Colombia are outlined.