An uninterruptible power supply (UPS) system is provided. The UPS system includes a plurality of UPSs, a ring bus coupled to the UPSs, a plurality of chokes, and at least one static switch coupled between an associated UPS of the UPSs and the ring bus. Each choke electrically couples an associated UPS to the ring bus. The static switch is switchable to selectively bypass at least one choke.

There is provided a radio access node (40) for use in a communication network (32), the radio access node (40) being associated with a local energy storage system (122) that is part of a distributed energy storage network, the radio access node (40) being adapted to monitor the operation of a power distribution network (118); in the event of a fault in the power distribution network (118), control the local energy storage system (122) to supply power to the power distribution network (118). A radio access node (40) for use in a communication network (32) is provided. The node (40) is able to locate a fault on a power distribution network (118) and to generate a map of at least a part of said power distribution network (118), indicating the location of the fault.

A method of operating a power generation system, such as a fuel cell power generation system, includes providing a first electrical power up to a threshold amount of power to a load from at least one power module via a plurality of DC/DC converters and a DC power bus, determining whether electrical power from a utility is available, and providing a second electrical power from the at least one power module to a rectifier path via a plurality of DC/AC inverters in response to determining that the electrical power from the utility is available. The second electrical power includes electrical power generated by the at least one power module in excess of the threshold amount of electrical power.

Examples of the disclosure include a power system comprising an input to receive input power, an output to provide power to a load, a sensor configured to provide load information indicative of power drawn by the load, a plurality of power modules, each having a power module input configured to be coupled to the input, and a power module output configured to be coupled to the output, and a controller coupled to the power modules and the sensor, and being configured to control the power modules to provide power to the output, receive the load information from the sensor, select, based on the load information, at least one power module to maintain in an active state to provide power to the output, and deactivate each power module other than the at least one power module based on selecting the at least one power module to maintain in the active state.

A data center includes a server rack and a back-up battery rack. The back-up battery rack includes a plurality of battery modules, each of which has completed a primary usage as an emergency power source for the server rack. A monitoring device determines a system configuration of the plurality of battery modules in the back-up battery rack, based on a specification required for the back-up battery rack and a history characteristic of each of the battery modules that has completed the primary usage in the server rack.

A data center includes a server rack and a back-up battery rack. The back-up battery rack includes a plurality of battery modules, each of which has completed a primary usage as an emergency power source for the server rack. A monitoring device determines a system configuration of the plurality of battery modules in the back-up battery rack, based on a specification required for the back-up battery rack and a history characteristic of each of the battery modules that has completed the primary usage in the server rack.

A method for operating a power factor correction (PFC) circuit of an uninterruptible power supply (UPS) apparatus is provided. The PFC circuit includes two T-type converters, and each of the T-type converters includes four switching tubes. The method includes: converting AC input voltage into a positive bus voltage across a first capacitor and a negative bus voltage across a second capacitor that is connected in series with the first capacitor when the UPS apparatus is operated under a normal supply mode; and controlling conduction states of the switching tubes of the T-type converters to balance the positive bus voltage and the negative bus voltage when the UPS apparatus is operated under a battery supply mode.

A power supplying device comprising a battery, a charging circuit and a DC-AC conversion circuit is provided. The charging circuit is electrically coupled to an AC power source and configured to charge the battery. The DC-AC conversion circuit is electrically coupled to the battery and configured to supply an AC output. When the power supplying device is powered on, both of the charging circuit and the DC-AC conversion circuit are enabled.

The invention provides a method and system for operating an inverter based distributed power generation source with energy storage system, as a Flexible AC Transmission System (FACTS) device—a STATCOM. The inverter based distributed power generation source can provide reactive power compensation, voltage regulation, damping enhancement, stability improvement and other benefits provided by FACTS devices. These STATCOM functions are provided when the said energy storage based distributed power generation source is doing at least one of: i) not exchanging active power with said power grid system, or ii) exchanging active power less than a maximum inverter capacity with said power grid system. The present invention thus provides a technological improvement that opens up a new set of applications and potential revenue earning opportunities for energy storage based distributed power generation sources other than simply from exchanging (injecting or absorbing) active power.

The invention provides a method and system for operating an inverter based distributed power generation source with energy storage system, as a Flexible AC Transmission System (FACTS) device—a STATCOM. The inverter based distributed power generation source can provide reactive power compensation, voltage regulation, damping enhancement, stability improvement and other benefits provided by FACTS devices. These STATCOM functions are provided when the said energy storage based distributed power generation source is doing at least one of: i) not exchanging active power with said power grid system, or ii) exchanging active power less than a maximum inverter capacity with said power grid system. The present invention thus provides a technological improvement that opens up a new set of applications and potential revenue earning opportunities for energy storage based distributed power generation sources other than simply from exchanging (injecting or absorbing) active power.