Recently, communication requirements assumed a greater importance following interest in smart grid and cities. This type of communication is simply aimed to facilitate a wide range of applications, i.e. from metering to protection purposes. The traditional power line communication (PLC) has been used for many years over high voltage power lines but there is a need for expanding PLC applications for a more reliable operation of smart grids. For this purpose, this paper seeks to examine PLC application at the medium and low voltage sides over distribution transformers and proposes the transmission line model (TLM) technique to develop high frequency models of power apparatus (line and distribution transformer). The models are then verified by real time experiments on a distribution transformer (50kVA, 34.5/0.4 kV, 50Hz, oil insulated, delta/star connected). Laboratory experiments show that the proposed TLM model is suitable for high frequency modeling of a distribution transformer. Furthermore, the suggested technique is also compared to Matlab simulations.