Measurement and research of channel transmission properties on 10 kV medium voltage power lines. Part 2: Path loss

The path loss over the 10 kV medium voltage power line channels using the transmission line theory is analyzed. The path loss is obtained from field test of different feeders in two substations employing the signal transmitting/receiving mode. Impacts on the path loss are analyzed including the power network structure, parallel-connected capacitor and coupling modes. Results show that electrical equipments between the TX and RX affect the path loss most. These equipments including distribution transformers and branches introduce some drain losses. Other parts of the network have little impact on the path loss. In addition, parallel compensation capacitor groups connected to the bus almost have no effect on the path loss. The equivalent impedance of any component wired into the network through a branch has been smoothed by that branch. If the impedance of the equipment is lower, thus smoothness favors the reduction of the drain loss caused by the corresponding equipment. The path loss is lower in phase to phase coupling than that in phase to ground coupling. In the frequency range of interest, the corresponding value is 5-15 dB.