Abstract: A power distribution arrangement for distributing AC power to loads requiring AC power is disclosed. The power distribution arrangement comprises a power distribution substation comprising transformers, switches, buses, and feeders, a DC transmission line, and at least one control unit. The control unit may control operation of the switches to selectively connect or disconnect one or more feeders to or from at least one transformer via one or more buses and to selectively connect or disconnect the DC transmission line to or from one or more feeders via at least one bus, whereby AC power is distributed to the loads via the feeders. The control unit may control operation of the switches based on: loading in and a power transfer rating of respective feeders and transformers, and any power transfer via the DC transmission line from the other power distribution substation to the at least one bus.

Abstract: Method (300) of controlling a distribution network (1) and a microgrid controller (8) adapted for the method. The distribution network (1) comprises assets (3-7) in a first part (1a) and a second part (1b). which parts (1a, 1b) are selectively connected to each other into an interconnected state at a connection point (PCC). The method comprises monitoring (301, 306) and controlling (310) the assets (3-7) of the distribution network (1). In a first control mode (310A), the first part (1a) is controlled by a distribution network controller (9) and the second part is controlled by the microgrid controller (8).

Abstract: A microgrid control system including a plurality of distributed generators, loads and/or energy storages. The system includes a microgrid controller arrangement, and a network controller arrangement. The network controller is distributed and configured to perform measurements on the microgrid, send information to at least one other of the plurality of network controllers, and send information to the microgrid controller arrangement based on the performed measurements. The information sent to the microgrid controller arrangement relates to assets which are included in a segment of the microgrid with which the controller is associated. The microgrid controller arrangement is configured to control the plurality of assets by instructing respective converter controller of each of the plurality of assets.

Abstract: A method for controlling power in a microgrid that includes power sources, loads and at least one connection to a main grid where a transformer is arranged to transfer electric power between the microgrid and the main grid is disclosed. The method includes: monitoring the power balance within the microgrid; monitoring the transformer, including monitoring the transformer temperature; and detecting a need for overloading the transformer based on the power balance within the microgrid. Especially, the method includes: determining a load profile for the transformer based on the power balance within the microgrid; determining a prognosis of the transformer temperature based on the load profile; and determining a schedule for power control of the microgrid, which determining of a schedule for power control includes analyzing the prognosis of the transformer temperature.

Abstract: The invention concerns a switchyard for interconnecting direct current power networks and a direct current power transmission system comprising such a switchyard. The switchyard comprises a number of interconnected entities comprising at least two main circuit breakers and a number of transfer switches, where each network has two connections to the switchyard, at least one via a transfer switch, each main circuit breaker has four connections in the switchyard, two at each end of the main circuit breaker and at least one via a transfer switch, and each network is joined with every other network via a corresponding path through at least one main circuit breaker as well as via a corresponding path bypassing all main circuit breakers.

Abstract: A method performed in an electrical microgrid for facilitating connection of a first and second AC power networks. The method includes, when the power networks are disconnected, from the second power network, controlling the AC frequency of the first power network based on the AC frequency of the second power network for ensuring that when the first and second networks are connected power will flow from the power network of the first and second power networks having a higher frequency to the power network of the first and second power networks having a lower frequency. The method also includes, after the controlling, connecting the first power network to the second power network, whereby power, at the instant of connecting, flows from the power network of the first and second power networks having a higher frequency to the power network of the first and second power networks having a lower frequency.

Abstract: A method of controlling a microgrid including at least one distributed generator (DG) and arranged for being connected to a power grid, by means of a converter via which the DG is connected in said microgrid. The method includes running the converter in a current control mode for controlling at least one current output of the DG in the microgrid; obtaining an indication that the converter should change from the current control mode towards a voltage control mode for controlling a voltage output of the DG in the microgrid; and entering the converter in an interstate mode, in response to the obtained indication, in which interstate mode the converter is configured for controlling both the current output and the voltage output.

Abstract: A method is performed by a control unit for controlling an energy storage configured for stabilizing a microgrid.

Abstract: A distributed method is provided for controlling electrical power in a microgrid, wherein a plurality of distributed generators supply electrical power to the microgrid, and each of the distributed generators is connected to a controller for controlling the real and reactive output power from the distributed generator.

Abstract: A microgrid connecting at least one distributed electricity generator includes a first switch configured for, in a closed position, connecting the microgrid to a first network line at a first point of common coupling (PCC) and for, in an open position, disconnecting the microgrid from the first network line at the first PCC; a second switch configured for, in a closed position, connecting the microgrid to a second network line at a second PCC, and for, in an open position, disconnecting the microgrid from the second network line at the second PCC; and a control unit configured for, when an islanding event has been detected when the second switch is in its closed position and the first switch is in its open position, acting to close the first switch, bringing it to its closed position.

Abstract: A method and system for controlling electrical power in a micro-grid, especially during islanding when the micro-grid is disconnected from a main grid is described. A potential load shedding for islanding is determined when the micro grid is connected to the main grid. The potential load shedding is performed when a grid switch that connects the micro-grid to a main grid opens. A frequency based load shedding and a frequency based control of power injections to the micro grid may also be performed. The frequency based load shedding is performed with a faster response than the power injection control during islanding. The frequency based power injection control is performed with a faster response than the frequency based load shedding when the micro grid is connected to the main grid. A load shedding controller, an energy storage controller and methods performed by the load shedding controller, and the energy storage controller, respectively, is also provided.