The detection of partial discharge in GIS plays a pivotal role in preventing and mitigating severe operational failure and damage in insulation elements. Partial discharge progressively degrades the insulating medium and, as a result electrical breakdown can occur in GIS. Despite various techniques used for PD detection, the RF analysis is extensively used because it is highly reliable, has good sensitivity and the largest bandwidth. The objective of this study is to examine two applicable planar antennas for detecting the RF energy of partial discharge in GIS infrastructure. Namely, a planar complex spiral antenna and a fractal tree log-periodic dipole antenna which are located on the GIS junction of segments.