Abstract: A power conversion device which converts electrical power generated by a distributed energy resource into electrical power corresponding to a power system is provided, comprising a communication unit which periodically receives, via communication, reception information indicating whether an accident has occurred in the power system, a disconnection unit which disconnects the distributed energy resource from the power system when the communication unit receives the reception information indicating accident occurrence, and a control unit which starts an islanding determination process for determining whether the distributed energy resource is in an islanding state by detecting a change in AC characteristics in the power system, when the communication unit does not receive the reception information for a predetermined first period.

Abstract: In order to output sufficient reactive power for voltage stabilization of a utility grid, and calculate an appropriate consideration according to an amount of the output reactive power, is provided a control device for controlling a distributed power source connected to the utility grid, comprising: a range setting unit where an allowable range of reactive and active powers output at normal times is set; an output control unit for controlling the reactive and active powers supplied from the distributed power source to the utility grid within the allowable range set in the range setting unit; and a reception unit for receiving, from a command device in the utility grid, an excess output command indicating that the reactive power exceeding the allowable range should be output, wherein the output control unit is for outputting the reactive power out of the allowable range when the reception unit receives the excess output command.

Abstract: A grid connected inverter is connectable to a power grid having a synchronous generator connected thereto, and is operable according to an output active power command generated by a virtual synchronous generator control function, to thereby reduce grid frequency variation. The output active power command is represented by a sum of a set value of the output active power of the grid connected inverter, a value obtained by multiplying a pseudo attenuation coefficient to a frequency deviation between a grid frequency and a reference frequency, and a value obtained by multiplying a pseudo inertia coefficient to a derivative value of the grid frequency. The pseudo inertia coefficient after the grid frequency reaches a maximum point of frequency variation is adjusted to a value smaller than the pseudo inertia coefficient before the grid frequency reaches the maximum point of frequency variation.

Abstract: It is desirable to improve the accuracy of voltage control in the grid interconnection device for supplying the power generated by the distributed power source to the interconnection point. Provided is a grid interconnection device for supplying power generated by a distributed power source to an interconnection point, comprising: a calculation unit for calculating voltage at the interconnection point based on output voltage of the grid interconnection device, output current of the grid interconnection device, and an impedance component between the grid interconnection device and the interconnection point; and a control unit for controlling output power from the grid interconnection device, based on voltage at the interconnection point calculated by the calculation unit.

Abstract: It is desirable to improve the accuracy of voltage control in the grid interconnection device for supplying the power generated by the distributed power source to the interconnection point. Provided is a grid interconnection device for supplying power generated by a distributed power source to an interconnection point, comprising: a calculation unit for calculating voltage at the interconnection point based on output voltage of the grid interconnection device, output current of the grid interconnection device, and an impedance component between the grid interconnection device and the interconnection point; and a control unit for controlling output power from the grid interconnection device, based on voltage at the interconnection point calculated by the calculation unit.

Abstract: A grid connected inverter is connectable to a power grid having a synchronous generator connected thereto, and is operable according to an output active power command generated by a virtual synchronous generator control function, to thereby reduce grid frequency variation. The output active power command is represented by a sum of a set value of the output active power of the grid connected inverter, a value obtained by multiplying a pseudo attenuation coefficient to a frequency deviation between a grid frequency and a reference frequency, and a value obtained by multiplying a pseudo inertia coefficient to a derivative value of the grid frequency. The pseudo inertia coefficient after the grid frequency reaches a maximum point of frequency variation is adjusted to a value smaller than the pseudo inertia coefficient before the grid frequency reaches the maximum point of frequency variation.

Abstract: In order to output sufficient reactive power for voltage stabilization of a utility grid, and calculate an appropriate consideration according to an amount of the output reactive power, is provided a control device for controlling a distributed power source connected to the utility grid, comprising: a range setting unit where an allowable range of reactive and active powers output at normal times is set; an output control unit for controlling the reactive and active powers supplied from the distributed power source to the utility grid within the allowable range set in the range setting unit; and a reception unit for receiving, from a command device in the utility grid, an excess output command indicating that the reactive power exceeding the allowable range should be output, wherein the output control unit is for outputting the reactive power out of the allowable range when the reception unit receives the excess output command.

Abstract: A power conversion device which converts electrical power generated by a distributed energy resource into electrical power corresponding to a power system is provided, comprising a communication unit which periodically receives, via communication, reception information indicating whether an accident has occurred in the power system, a disconnection unit which disconnects the distributed energy resource from the power system when the communication unit receives the reception information indicating accident occurrence, and a control unit which starts an islanding determination process for determining whether the distributed energy resource is in an islanding state by detecting a change in AC characteristics in the power system, when the communication unit does not receive the reception information for a predetermined first period.