抄録
When a photovoltaic power generation system is to be connected with a low voltage distribution line, it is necessary to install an insulated transformer or interrupt the operation of an inverter by detecting the direct current leaking from the inverter, in order to prevent the occurrence of asymmetrical excitation of a distribution pole transformer due to the flow of direct current into it.
In this paper, the phenomenon of asymmetrical excitation of a distribution pole transformer due to direct current inflows was studied both experimentally and through a theoretical simulation, in order to clarify the detection level of the direct current in question. Test results showed that the excitation current increases in proportion to the direct current, and that the smaller the transformer capacity, the larger the ratio of the excitation current to the rated load current. These findings agreed with the results of the theoretical simulation.
