Abstract: A support system for an AC power transmission system, comprising an energy storage arrangement comprising a plurality of storage units and a main controller configured to control the operation of the energy storage arrangement. Each storage unit comprises at least three control signal connections and is configured to receive a control signal from at least three storage entities via said control signal connections, wherein each of the storage entities is either the main controller or a storage unit controller of an adjacent storage unit. The storage units are arranged to forward a control signal received via a first one of said control signal connections to all adjacent storage units that are connected via the remaining ones of said control signal connections.

Abstract: A power supporting arrangement for a power grid includes a first and a second voltage source converter with an AC side and a DC side. A DC link interconnects the DC sides of the voltage source converters. A first switching arrangement includes a number of settable positions. The AC side of the second voltage source converter is connected to the power grid and the first switching arrangement is connected between a first synchronous machine. The AC side of the first voltage source converter and the power grid and operable to selectively connect the first synchronous machine to the power grid or to the AC side of the first voltage source converter.

Abstract: A support system for an AC power transmission system, comprising an energy storage arrangement comprising a plurality of storage units and a main controller configured to control the operation of the energy storage arrangement. Each storage unit comprises at least three control signal connections and is configured to receive a control signal from at least three storage entities via said control signal connections, wherein each of the storage entities is either the main controller or a storage unit controller of an adjacent storage unit. The storage units are arranged to forward a control signal received via a first one of said control signal connections to all adjacent storage units that are connected via the remaining ones of said control signal connections.

Abstract: An energy storage system and a method for controlling such a system is disclosed. The energy storage system comprises a plurality of interconnected energy storage cells forming an energy storage module, a power converter connected to the energy storage module, a resistor circuit connected in parallel to the energy storage module, a switch connected in series with the resistor circuit and configured to disconnect the resistor circuit from the energy storage module, and a control unit operably connected to the switch. The control unit is configured to receive information pertaining to a transmission of energy in the energy storage system and to control the switch based on said information.

Abstract: A power supporting arrangement includes a DC network having a first DC line with a first DC potential, a second DC line with a second DC potential, and an energy storage system that includes a first energy storage unit connected in a branch between the first and the second DC lines. A first group of phase arms is connected in a wye-configuration between the power grid and the first DC line and a second group of phase arms connected in a wye-configuration between the power grid and the second DC line. The first and second groups of phase arms are controllable as a voltage source converter. A third group of phase arms is connected to the power grid in a wye-configuration. The third group of phase arms have a neutral point and being controllable to support the power grid with reactive power.

Abstract: A power supporting arrangement for a power grid includes a first and a second voltage source converter with an AC side and a DC side. A DC link interconnects the DC sides of the voltage source converters. A first switching arrangement includes a number of settable positions. The AC side of the second voltage source converter is connected to the power grid and the first switching arrangement is connected between a first synchronous machine. The AC side of the first voltage source converter and the power grid and operable to selectively connect the first synchronous machine to the power grid or to the AC side of the first voltage source converter.