On the effective length of transmission line grounding conductors and the validity of the point-source model in GPR responses

Due to long extensions involved, being exposed to the environment, and occupying large amounts of space, transmission lines (TLs) eventually interfere electromagnetically with other metallic structures. Electromagnetic interferences (EMIs) often generate risks to the safety of the installations and people involved. Realistic approaches to address EMI studies are often computationally intensive. Thus, simplified models that accurately represent real phenomena are very important. In this context, this paper determines the effective distance from the observation point in which the TLs tower grounding system can be replaced by a simplified point-source model. A hypothetical case of parallelism is performed to validate the proposed methodology. Results show that from a distance of three times the counterpoise conductors length, the simplified model can be used in several hypothetical scenarios of discrepancy. The results obtained using the effective distance and the simplified model presented a 2.89% discrepancy and an improvement of 11.77% in software performance.