Partial discharges (PD) are small current pulses that can occur within the insulation of medium and high voltage (HV) electrical assets such as cable accessories, transformers and switchgear. In GIS units, PD's can occur near the high-voltage conductor or at other locations commonly due to metallic particles from the erosion of the switchgear contacts or left behind after maintenance. For that reason, GIS units are usually equipped with multiple embedded UHF sensors in selected compartments that can detect PD in their vicinity.