Abstract: There is disclosed herein an energy storage system comprising an energy storage circuit, comprising a string of interconnected energy storage units configured to store electrical energy and provide power to a power grid using said stored electrical energy. The ESS further comprises an auxiliary module configured to provide auxiliary functions for at least one of the plurality of energy storage units, and an auxiliary power supply circuit for providing power to the auxiliary module from a grounded power source. The auxiliary power supply circuit is configured to galvanically isolate the energy storage circuit from the grounded power source, thereby preventing electrical arcing between the ESS, which may be at a high voltage, and ground at the grounded power source.

Abstract: There is disclosed herein an energy storage system comprising an energy storage circuit, comprising a string of interconnected energy storage units configured to store electrical energy and provide power to a power grid using said stored electrical energy. The ESS further comprises an auxiliary module configured to provide auxiliary functions for at least one of the plurality of energy storage units, and an auxiliary power supply circuit for providing power to the auxiliary module from a grounded power source. The auxiliary power supply circuit is configured to galvanically isolate the energy storage circuit from the grounded power source, thereby preventing electrical arcing between the ESS, which may be at a high voltage, and ground at the grounded power source.

Abstract: There is disclosed herein a method for fault-response in an energy storage system (ESS), wherein the ESS comprises a string of series-connected energy storage cabinets (110), and the string of energy storage cabinets comprises at least two energy storage cabinets (110A, 110B) and a discharge resistor (150) arranged such that the discharge resistor is selectively connectable to each or both of the two cabinets (110A, 110B). The method comprises detecting a failure of a first cabinet (110A) of the two cabinets (110A, 110B) and, in response to detecting the failure of the first cabinet (110A), selectively electrically connecting the discharge resistor (150) to the first cabinet (110A), thereby discharging electrical energy stored in the first cabinet (110A) via the discharge resistor (150).

Abstract: A module (100) for use in an energy storage system is provided, including a first terminal (110) and a second terminal (112); a supercapacitor branch (120) including an arrangement (122) of one or more supercapacitors (124), and a resistive bypass branch (130) including at least a first bypass switch (132) and a resistance (134) connected in series. The supercapacitor branch and the resistive bypass branch are connected in parallel between the first terminal and the second terminal. The module may further include a direct bypass branch (140) having a second bypass switch (142), the direct bypass branch being also connected in parallel with the supercapacitor branch (120) between the first and second terminals. A control method of such a module and an energy storage system including several such modules, are also provided.

Abstract: A system (100) for stabilising a power grid (102), comprising a generator (104), configured to provide power to the power grid (102), the power having an active power component and a reactive power component, and a power line (106), configured to transmit power from the generator (104) to the power grid (102). The system (100) comprises a thyristor controlled braking resistor (TCBR) (108) arranged on the power line (106), and a capacitor (110) electrically connected in series with the TCBR (108). The TCBR (108) absorbs at least a portion of the reactive power component from the generator (104) during a fault on the power line (106) and the capacitor (110) is configured to compensate for the at least a portion of the reactive power component absorbed by the TCBR (108).

Abstract: A module (100) for use in an energy storage system is provided, including a first terminal (110) and a second terminal (112); a supercapacitor branch (120) including an arrangement (122) of one or more supercapacitors (124), and a resistive bypass branch (130) including at least a first bypass switch (132) and a resistance (134) connected in series. The supercapacitor branch and the resistive bypass branch are connected in parallel between the first terminal and the second terminal. The module may further include a direct bypass branch (140) having a second bypass switch (142), the direct bypass branch being also connected in parallel with the supercapacitor branch (120) between the first and second terminals. A control method of such a module and an energy storage system including several such modules, are also provided.

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: 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.

Abstract: A thyristor controlled series capacitor module including a capacitor connectable in series with a power line, a thyristor valve connected in parallel with the capacitor, a breaker connected in parallel with the thyristor valve, and an inductor. By providing a simplified breaker arrangement, the number of components is reduced.

Abstract: A thyristor controlled series capacitor module including a capacitor connectable in series with a power line, a thyristor valve connected in parallel with the capacitor, a breaker connected in parallel with the thyristor valve, and an inductor. By providing a simplified breaker arrangement, the number of components is reduced.