Experimental Validation and Parametrisation of a High Impedance Fault Model for Overhead Distribution Networks Vegetation Simulations: Insights From Medium Voltage Laboratory Tests on Tree Branches

The detection and localisation of high impedance faults (HIFs) in overhead distribution networks, particularly those caused by tree contact, remain challenging due to their low fault current magnitude, nonlinear behaviour, and high waveform variability. This study addresses these challenges by experimentally validating and parameterising a two-variable-resistor series model for HIFs. Controlled tests were conducted at the 13.8 kV Extra High Voltage Laboratory (LEAT) of the Federal University of Pará (UFPA), Brazil, using three tree types to collect waveform data. The faults were modelled in ATPDraw software and validated through waveform comparisons, achieving an R² coefficient above 0.89, demonstrating excellent agreement between simulated and measured signals. Additionally, comprehensive parameterised data tables detailing resistance variations over time and voltage are provided. These findings not only reduce the need for costly experimental setups in early-stage studies but also provide a solid foundation for developing and testing advanced HIF detection and localisation algorithms, thus contributing to improved power distribution system reliability.