A PLC frequency model of 3 phase power distribution transformers

A model of a 200 kVA, 240 V to 11 kV, 3 phase power distribution transformer is presented. 1000 impedance measurements, covering a frequency range of 50Hz to 5 MHz were made on each of 23 terminal combinations for this unenergized transformer. The model consists of 21 circuit elements per phase plus 2 circuit elements for neutral to transformer case coupling. That model is then optimized to minimize the differences between the model and the measurements, resulting in an accurate wide frequency range model. This model can then be used for SmartGrid PLC system design, to ensure that PLC coupling networks work well with the transformers and that all PLC modems on the network can effectively communicate to the control system.