Analysis of Cable Length Dependency on Common Mode Current by Using Scale Model for Power Line Communication

Power line communication (PLC) is the technology that uses a power line as a signal line. Because an imbalance of the power line is generally larger than that of the communication line, we should take care of radiated emission from the PLC cable. A small-scale model can be applied to evaluate easily the radiated emission from PLC cables for large structures. In a scale model, all structures in the PLC system need to be manufactured as 1/n size to satisfy complete equivalence between the reference model and its scale model, though it is difficult to fabricate the fine structure such as conductors in a cable smaller. Therefore we investigated the effect on common-mode current when some parameters of the scale model were not scaled down perfectly. As a result, a reliable scale model was obtained to evaluate peak common-mode currents in resonant frequency even if some parameters of the structure were incompletely scaled. Furthermore, the cable length dependency of common-mode current was evaluated experimentally by using the scale model.