Abstract: The monitoring system includes: a management server, and a transmission device which obtains, from the power storage system, first charged power index values indicating charged power of the power storage system and input/output power index values indicating input/output power from the power receiving point to which the power storage system is connected to a system, and transmits the index values to the management server via a network. The management server includes: a calculation part which calculates, based on the first charged power index values and the input/output power index values, second charged power index values indicating power charged by generated power of the power generation system connected to the power receiving point of charged power of the power storage system; and a diagnosis part which diagnoses presence or absence of abnormality of the power generation system based on the second charged power index values calculated by the calculation part.

Abstract: A power storage power conditioner includes an input part, a voltage-transforming part, a first input-output part, a converting part and a second input-output part. The voltage-transforming part transforms the voltage of DC power from the input part and the converting part into a second predetermined voltage. The first input-output part outputs the DC power of the voltage-transforming part to a battery unit, and inputs DC power from the battery unit. The voltage-transforming part transforms a voltage of the DC power from the first input-output part into a third predetermined voltage. The converting part converts the DC power from the input part and the voltage-transforming part into AC power. The second input-output part outputs the AC power to a power system or a load, and inputs AC power from the power system. The converting part converts the AC power from the second input-output part into DC power.

Abstract: A power storage power conditioner includes an input part, a voltage-transforming part, a first input-output part, a converting part and a second input-output part. The voltage-transforming part transforms the voltage of DC power from the input part and the converting part into a second predetermined voltage. The first input-output part outputs the DC power of the voltage-transforming part to a battery unit, and inputs DC power from the battery unit. The voltage-transforming part transforms a voltage of the DC power from the first input-output part into a third predetermined voltage. The converting part converts the DC power from the input part and the voltage-transforming part into AC power. The second input-output part outputs the AC power to a power system or a load, and inputs AC power from the power system. The converting part converts the AC power from the second input-output part into DC power.

Abstract: As having a charge/discharge control function of storage batteries, when a plurality of power conditioners having a same basic switching period are installed together, hunting of charging/discharging power of the storage battery connected to each power conditioner is suppressed. Execution periods of control processes performed by control units 14 of a plurality of power conditioners 10 that have a function of controlling charging and discharging of storage batteries 25 are changed from basic switching periods so as to be different from each other.

Abstract: A distributed power system that is connected to a utility grid during both daytime and nighttime includes a plurality of power supplies including a solar array, a non-isolated DC-DC converter that has an input terminal and an output terminal and raises, at a predetermined step-up ratio, a DC voltage input from the power supplies via the input terminal and outputs the DC voltage via the output terminal, an inverter that converts the DC voltage output from the DC-DC converter via the output terminal into an alternating current, and a potential adjustment section that adjusts a potential at a negative electrode of the solar array to a potential higher than a potential at a negative electrode of the inverter at least during nighttime.

Abstract: A distributed power system that is connected to a utility grid during both daytime and nighttime includes a plurality of power supplies including a solar array, a non-isolated DC-DC converter that has an input terminal and an output terminal and raises, at a predetermined step-up ratio, a DC voltage input from the power supplies via the input terminal and outputs the DC voltage via the output terminal, an inverter that converts the DC voltage output from the DC-DC converter via the output terminal into an alternating current, and a potential adjustment section that adjusts a potential at a negative electrode of the solar array to a potential higher than a potential at a negative electrode of the inverter at least during nighttime.