A method for operating a renewable energy power system connected to a power grid includes operating the renewable energy power system at one or more first operational settings. The method also includes monitoring the renewable energy power system for electrical oscillations caused by a grid or system disturbance. In response to detecting the electrical oscillations being above a predetermined threshold indicative of the one or more first operational settings no longer being suitable for grid conditions, the method includes changing the one or more first operational settings to one or more different, second operational settings so as to reduce the electrical oscillations in the renewable energy power system.

A method for operating a renewable energy power system connected to a power grid includes operating the renewable energy power system at one or more first operational settings. The method also includes monitoring the renewable energy power system for electrical oscillations caused by a grid or system disturbance. In response to detecting the electrical oscillations being above a predetermined threshold indicative of the one or more first operational settings no longer being suitable for grid conditions, the method includes changing the one or more first operational settings to one or more different, second operational settings so as to reduce the electrical oscillations in the renewable energy power system.

This disclosure relates to a hierarchical power control system linked to a cloud server comprising a first microgrid cell including a first ESS equipped with a UPS structure and a first load with a power state managed by the first ESS; a second microgrid cell including a second load and a second ESS that manages a power state of the second load; a third microgrid cell including a third load; an emergency cell including an additional ESS equipped with a UPS structure and an additional emergency generator, and selectively connected to the second microgrid cell; a middleware server which communicates with the first to third microgrid cells and the emergency cell; and an integrated control system for receiving power supply state information of the first to third microgrid cells, and establishing an integrated operation schedule based on the received power supply state information of the first to third microgrid cells.

This disclosure relates to a hierarchical power control system linked to a cloud server comprising a first microgrid cell including a first ESS equipped with a UPS structure and a first load with a power state managed by the first ESS; a second microgrid cell including a second load and a second ESS that manages a power state of the second load; a third microgrid cell including a third load; an emergency cell including an additional ESS equipped with a UPS structure and an additional emergency generator, and selectively connected to the second microgrid cell; a middleware server which communicates with the first to third microgrid cells and the emergency cell; and an integrated control system for receiving power supply state information of the first to third microgrid cells, and establishing an integrated operation schedule based on the received power supply state information of the first to third microgrid cells.

Provided in the present invention are a microgrid control system and a microgrid, the microgrid control system comprising: a grid-connected switch, an energy router, a first controller and a second controller; the first controller controls the grid-connected switch and sends a first control instruction; the second controller receives the first control instruction and responds to the first control instruction for controlling the energy router.

A system for handling short circuits on an electrical network comprising parallel operated units which are droop controlled for active and reactive power sharing and connected to each other via impedances and protection switches for detecting and handling a short circuit on the electrical network and for disconnecting the faulty part of the electrical network, said units including a DC-source and a grid forming voltage source inverter controlled by a cascaded control structure with an inner voltage control loop and a short circuit control for limiting the output current by changing the output voltage at the output terminals of the inverter as a function of the measured output current and a desired droop voltage provided by a droop controller for voltage and frequency power sharing.

A power-on/off command is output to a breaker for switching when a frequency difference between a plurality of electric power supply sources is within a predetermined range and a phase difference between the plurality of electric power supply sources is within a predetermined range, in switching of electric power supply between the plurality of electric power supply sources. A generator drive rotation speed of a transmission device is feedback controlled so that the frequency difference is maintained at a value within the predetermined range and the phase difference is maintained at a value within the predetermined range when the detected frequency difference is within the predetermined range and the detected phase difference is within the predetermined range. A generator rotation speed command is calculated by adding to the rotation speed command of the transmission device an output value obtained by subjecting the detected phase difference to a proportional-integral-control.

A method for operating a wind turbine configured to supply electrical power to an electrical power supply network via a converter comprises measuring a phase angle and measuring a voltage of the electrical power supply network. A value of at least one parameter for a phase locked loop is determined depending on the measured voltage. The phase locked loop is used to determine a corrected phase angle depending on the measured phase angle and the voltage of the electrical power supply network. The corrected phase angle is input into the converter.

An electric circuit for regulating power transfer in a power grid includes a compensator circuit arranged to be connected between outputs of one or more power sources and a point of common coupling in the power grid. The compensator circuit is arranged to detect one or more electrical properties associated with the outputs and one or more electrical properties associated with the point of common coupling; and provide, based on the detection, a voltage output to emulate a resistor for suppressing filter resonance associated with the one or more power sources and to reduce equivalent impedance of the power grid.

An energy storage system that comprises an energy reservoir and a system controller. The energy reservoir is charged by DC energy from a DC energy source while discharging DC energy to a DC/AC converter. A system controller regulates the DC energy discharged from the energy reservoir to the DC/AC converter to nearly balance the amount of DC energy charged into the energy reservoir. Because this charging and discharging is nearly balanced, the size of the energy reservoir can be made quite small relative to the amount of charging and discharging. This is advantageous where the flow of charge and discharge is high, as might be the case if the energy reservoir receives charge from all or a substantial portion of a power station, such as a solar power station. With such a controller, the use of an energy reservoir becomes technically feasible even with such large current flows.