A distributed power system (100, 101, 102, 131, 132, 133) to be connected to a utility grid during both daytime and nighttime, the system (100, 101, 102, 131, 132, 133) comprising: a plurality of power supplies including a solar array; a non-isolated DC-DC converter (120 - 124) having an input terminal (22,23) and an output terminal (24,25), and configured to raise, at a predetermined step-up ratio, a DC voltage input from the power supplies via the input terminal (22,23) and to output the DC voltage via the output terminal (24,25); and an inverter configured to convert the DC voltage output from the non-isolated DC-DC converter (120 -124) via the output terminal into an alternating current, wherein the non-isolated DC-DC converter (120 - 124) includes a potential adjustment section, wherein the non-isolated DC-DC converter (120 - 124) further includes at least a first reactor and a second reactor, a first diode and a second diode, a capacitor (C1,C4,C5), and a switching element, and the potential adjustment section includes a series-connected circuit configuration in which a first terminal of the first reactor is connected to a positive electrode of the input terminal of the non-isolated DC-DC converter, a second terminal of the first reactor is connected to an anode of the first diode, and a cathode of the first diode is connected to a positive electrode of the output terminal of the non-isolated DC-DC converter (120 - 124), and a first terminal of the second reactor is connected to a negative electrode of the input terminal of the non-isolated DC-DC converter (120 - 124), a second terminal of the second reactor is connected to a cathode of the second diode, and an anode of the second diode is connected to a negative electrode of the output terminal of the non-isolated DC-DC converter, characterised in that the potential adjustment section is configured to adjust a potential at a negative electrode of the solar array to a potential higher than a potential at a negative electrode of the output terminal of the non-isolated DC-DC converter at least during night time. a plurality of power supplies including a solar array; a non-isolated DC-DC converter (120 - 124) having an input terminal (22,23) and an output terminal (24,25), and configured to raise, at a predetermined step-up ratio, a DC voltage input from the power supplies via the input terminal (22,23) and to output the DC voltage via the output terminal (24,25); and an inverter configured to convert the DC voltage output from the non-isolated DC-DC converter (120 -124) via the output terminal into an alternating current, wherein the non-isolated DC-DC converter (120 - 124) includes a potential adjustment section, wherein the non-isolated DC-DC converter (120 - 124) further includes at least a first reactor and a second reactor, a first diode and a second diode, a capacitor (C1,C4,C5), and a switching element, and the potential adjustment section includes a series-connected circuit configuration in which a first terminal of the first reactor is connected to a positive electrode of the input terminal of the non-isolated DC-DC converter, a second terminal of the first reactor is connected to an anode of the first diode, and a cathode of the first diode is connected to a positive electrode of the output terminal of the non-isolated DC-DC converter (120 - 124), and a first terminal of the second reactor is connected to a negative electrode of the input terminal of the non-isolated DC-DC converter (120 - 124), a second terminal of the second reactor is connected to a cathode of the second diode, and an anode of the second diode is connected to a negative electrode of the output terminal of the non-isolated DC-DC converter, characterised in that the potential adjustment section is configured to adjust a potential at a negative electrode of the solar array to a potential higher than a potential at a negative electrode of the output terminal of the non-isolated DC-DC converter at least during night time.