Hitachi Energy Ltd

Hitachi Energy Switzerland Ag

Lexuan Meng

Gunnar Ingeström

Tong Wu

Mohsen Asoodar

Per Karreby

Jan Svensson

Theodore Soong

Juergen Steinke

Haofeng Bai

Daniel Hallmans

Jan Kheir

Maria Werlefors

Mikael Tenerz

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.

Auxiliary power supply for energy storage systems

A module () for use in an energy storage system is provided, including a first terminal () and a second terminal (); a supercapacitor branch () including an arrangement () of one or more supercapacitors (), and a resistive bypass branch () including at least a first bypass switch () and a resistance () 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 () having a second bypass switch (), the direct bypass branch being also connected in parallel with the supercapacitor branch () 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.

Module for large scale energy storage

An arrangement is disclosed, comprising a series connection of a plurality of energy storage units, a plurality of bypass circuits, each bypass circuit being configured to bypass a respective one of the energy storage units in the series connection, and a plurality of control modules, wherein each control module corresponds to a respective one of the bypass circuits. Each control module is configured to control operation of the corresponding bypass circuit and at least one other bypass circuit of the plurality of bypass circuits to selectively bypass the corresponding energy storage units in the series connection in such a way that operation of each bypass circuit of the plurality of bypass circuits to selectively bypass the corresponding energy storage unit in the series connection is controllable by means of at least two of the control modules. A related method is also disclosed.

Arrangement comprising energy storage units and a related method

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.

Control platform architecture for grid integration of large-scale grid energy storage system

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.

Power supporting arrangement for a power grid

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Västerås, Sweden

Lexuan Meng