In the present work, the location of the partial discharge source in transformer insulation was analysed by simulation studies. The partial discharge source was modelled such that it radiates the Ultra High Frequency (UHF) signal. The time of arrival of the UHF signal and the magnitude of the UHF signal at any sensor depends on its distance from the partial discharge source. The effect of the barrier on the propagation of the signal was studied. It was observed that the signal attenuation increases with the increase in the thickness of the barrier. The arrival times of the signals at the sensors also vary depending on the available barriers. The location of the partial discharge source was analysed with and without the barrier. The time difference of arrival of the signal at the sensors was calculated based on the first peak method. © 2014 The Institute of Electrical Engineers, Japan.