Electrical apparatus (20) includes an inverter (24) having input terminals for receiving DC input power and output terminals for coupling to an AC power grid. A pulse-width modulation (PWM) generator and drivers (26) drive the switches so as to control respective amplitudes, frequencies, and phases of the output current waveforms of the inverter. Control circuitry (28) receives measurements of respective time-varying voltages and currents on the input and output terminals, computes a model (40) that includes three virtual currents flowing in a synchronous machine that is emulated by the apparatus, wherein the three virtual currents are associated respectively with the three output current waveforms, and controls the PWM generator and drivers responsively to the three virtual currents so as to synchronize the amplitudes, frequencies, and phases of the three output current waveforms of the inverter with the three phases of the AC power grid.

A method for controlling energy storage device includes determining whether the operating frequency of the system falls within a dead band range corresponding to a preset frequency range, determining whether an SOC level indicating the charging amount of the energy storage device falls within a preset maintaining range, in a case where the operating frequency falls within the dead band range, and adjusting the SOC level so that the SOC level falls within the maintaining range in a case where the operating frequency of the system falls within the dead band range and the SOC level is outside the preset maintaining range, wherein the maintaining range represents a range between a preset lower limit and a preset upper limit.

A method for mitigating voltage disturbances at a point of interconnection (POI) of a grid-forming inverter-based resource (IBR) due to flicker includes receiving a voltage reference command and a voltage feedback. The voltage feedback contains information indicative of the voltage disturbances at the POI due to the flicker. The method also includes determining a power reference signal for the IBR based on the voltage reference command and the voltage feedback. Moreover, the method includes generating a current vector reference signal based on the power reference signal, the current vector reference signal containing a frequency component of the voltage disturbances. Further, the method includes generating a transfer function of a regulator based on the frequency component to account for the flicker effect. In addition, the method includes generating a current vector based on a comparison of the current vector reference signal and a current vector feedback signal. Thus, the method includes regulating a voltage vector command using the current vector to mitigate the voltage disturbances.

A method for mitigating voltage disturbances at a point of interconnection (POI) of a grid-forming inverter-based resource (IBR) due to flicker includes receiving a voltage reference command and a voltage feedback. The voltage feedback contains information indicative of the voltage disturbances at the POI due to the flicker. The method also includes determining a power reference signal for the IBR based on the voltage reference command and the voltage feedback. Moreover, the method includes generating a current vector reference signal based on the power reference signal, the current vector reference signal containing a frequency component of the voltage disturbances. Further, the method includes generating a transfer function of a regulator based on the frequency component to account for the flicker effect. In addition, the method includes generating a current vector based on a comparison of the current vector reference signal and a current vector feedback signal. Thus, the method includes regulating a voltage vector command using the current vector to mitigate the voltage disturbances.

A device for stabilizing an AC voltage grid includes a power converter having an AC voltage side for connection to the AC voltage grid and a DC voltage side having two DC voltage poles. An energy storage arrangement is connected on the DC voltage side of the converter between the DC voltage poles. A controlled load for absorbing active power or consuming active power is disposed in series or parallel with the energy storage arrangement. A method is also provided for stabilizing an AC voltage grid by using the device.

A device for stabilizing an AC voltage grid includes a power converter having an AC voltage side for connection to the AC voltage grid and a DC voltage side having two DC voltage poles. An energy storage arrangement is connected on the DC voltage side of the converter between the DC voltage poles. A controlled load for absorbing active power or consuming active power is disposed in series or parallel with the energy storage arrangement. A method is also provided for stabilizing an AC voltage grid by using the device.

A method, apparatus, system and computer program is provided for controlling an electric power system, including implementation of voltage measurement using paired comparison analysis applied to calculating a shift in average usage per customer from one time period to another time period for a given electrical use population where the pairing process is optimized using a novel technique to improve the accuracy of the measurement.

A method, apparatus, system and computer program is provided for controlling an electric power system, including implementation of voltage measurement using paired comparison analysis applied to calculating a shift in average usage per customer from one time period to another time period for a given electrical use population where the pairing process is optimized using a novel technique to improve the accuracy of the measurement.

A method for determining synchronization transient stability of a power system and an electronic device are provided. The synchronous energy function corresponding to the power system model is determined; the synchronization convergence region is determined according to the synchronization energy function; it is determined whether the power system is transient stable according to the synchronization convergence region and the initial value of power system after fault; and adjusting parameters of the power system in response to determining that the power system is transient unstable.

A power system management device which manages a system state in a power system includes a system state candidate calculation unit for calculating state amounts of the system state based on an objective function from system characteristic information indicating characteristic information of a system structure, an inter-state distance calculation unit for calculating an inter-state distance representing a similarity of values between state amounts of the system state calculated by the system state candidate calculation unit, and a variability evaluation value calculation unit for calculating a variability evaluation value in which a variability of the system state is evaluated, based on an objective function value calculated from the state amount of the system state calculated by the system state candidate calculation unit and the inter-state distance calculated by the inter-state distance calculation unit. The system state is selected based on the calculated variability evaluation value.