In this paper, loss of a dc microgrid system for
residential complex is compared with loss in an ac system.
Each system has a PV system, a gas engine cogeneration and
20 residential houses. The losses are calculated from
measured load data and PV output data which was
estimated from global solar radiation and temperature of a
PV panel. The operation of the gas engine cogeneration is
determined from the heat demands. As house loads, we
consider an air conditioner, a refrigerator, a washing
machine and a liquid crystal display (LCD) in each house.
The loss calculation result shows the total losses in the dc
system are around 15 % lower than the losses in the ac
system