A power tool including a housing, a motor having a rotor and a stator, at least one grip sensor configured to generate a grip parameter, and a switching network electrically coupled to the brushless DC motor. An electronic processor is connected to the switching network and the at least one grip sensor and configured to implement kickback control of the power tool. The electronic processor is configured to determine a kickback threshold based on the grip parameter, control the switching network to drive the motor, receive a signal related to a power tool characteristic, determine, based on the power tool characteristic being greater than or equal to the kickback threshold, that a kickback event of the power tool is occurring, and control, in response to determining that the kickback event is occurring, the switching network to cease driving of the motor.

The present application concerns a transformer assembly. The transformer assembly includes a step-up transformer, a step-down transformer, and a phase shifting transformer having a source side and a load side connected, respectively, to the step-down transformer and the step-up transformer.

A power conversion device includes: a power converter connected to an AC grid to which a load is connected; and a control circuit. The control circuit includes a harmonic compensation unit that includes a current command generation unit and a limit coefficient calculation unit and compensates for harmonic current contained in load current. The current command generation unit generates compensation current desired values for respective frequency components, and corrects the compensation current desired values using corresponding limit coefficients, to generate compensation current commands for respective frequency components. The limit coefficient calculation unit calculates each limit coefficient, on the basis of the compensation current desired value for each frequency component, and maximum voltage and maximum current that the power converter can output.

A liquid cooling static synchronous series compensator (SSSC) system has inverter valve modules, inverter valve units and liquid cooling blocks. Liquid cooling blocks may be configured to provide a jetted flow, a parallel flow or an individualized flow, within an enclosed fluid chamber, for cooling inverter valve units. Liquid cooling blocks may have voltage isolation.

The present invention provides a power control circuit connectable to a load adapted to receive a power supply, the power control circuit adapted to absorb power from the power supply and adapted to deliver power to the power supply to stabilize at least one electrical parameter of the power supply. The present invention also provides an associated method of stabilizing at least one electrical parameter of a power supply connectable to a load, the method including absorbing power from the power supply or delivering power to the power supply. The at least one electrical parameter of the power supply includes parameters such as voltage and frequency.

A high-voltage hierarchy hundred-megawatt level (100 MW) battery energy storage system and optimizing and control methods are provided. The system includes a multi-phase structure, of which each phase is divided into multi-story spaces from top to bottom. A battery module is provided in each story of the multi-story spaces. The battery module is connected to a DC terminal of an H-bridge converter, and each phase is cascaded by the H-bridge converter. A capacity of the single-phase energy storage apparatus of the present invention is large, and multiple phases can be connected in parallel to form a 100 MW battery energy storage power station. The power station has the advantages of simple structure, easy coordinated control, low control loop model and coupling, and optimal system stability. The control system of the present invention has fewer hierarchies, a small information transmission delay, and a rapid response speed.

The invention relates to an apparatus for regulating electrical power in an electricity transmission network, the apparatus including: a DC contactor; a transmission network connector including live terminal(s) connected to live connection(s) and a neutral terminal connected to a neutral or earth of the electricity transmission network; switches connected to the DC contactor; electronic controlling devices coupled to the switches and control the switches to independently regulate electrical power on each of the live connection(s) and the neutral connection, the electronic controlling devices receive voltage reading of the live connection(s); calculate average of the voltage reading for the live connection(s); if the average is larger than an upper value, control the switches to reduce voltage on the live connection; if the average is less than a lower value, control the switches to increase voltage supplied on the live connection(s).

A distributed control system uses a central controller in Internet communication with a local controller to manage grid tie attachment with a battery to form an integrated battery energy storage system (BESS). The BESS is capable of charging or discharging the battery, as well as correcting grid phase with volt amp reactive (VAR) leading or lagging operation modes. Examples shown include simple BESS charging and discharging, BESS integrated with renewable energy sources (here photovoltaic), and direct current fast charge (DCFC) connections with an electric vehicle.

A battery energy storage system for use in providing balancing services to an electrical power distribution network is set to monitor the state of charge (SoC) of a storage battery (26). If the SoC is within an optimal range (48), the balancing service is provided solely by charging and discharging the battery. If the battery SoC falls below a predetermined low threshold (52), a first non-battery asset is operated to increase power supplied to the network. Similarly, if the battery SoC rises above a predetermined high threshold (50), a second non-battery asset is operated to provide the balancing service. With this arrangement, requirements on the energy storage capacity of the battery are reduced. For the system to meet balancing service regulatory requirements, the battery need only remain capable of charging or discharging beyond each threshold (50, 52) for a period of time that covers that taken for the respective asset to reach operational capacity.

A method for synchronized injection of impedance into high voltage (HV) transmission line is disclosed. The method includes generating, by a plurality of impedance injection units (IIUs) coupled to the HV transmission line, impedance injection waves that cumulatively form a pseudo-sinusoidal wave. The method further includes optimizing, by the plurality of IIUs, the pseudo-sinusoidal wave to represent a pure sinusoidal wave. The method further includes injecting, by the plurality of IIUs, the pseudo-sinusoidal wave, as impedance, into the HV transmission line. The plurality of IIUs form multiple connection configurations in sequence, each connection configuration comprising one IIU or multiple IIUs in series, parallel or combination thereof, coupled to the HV transmission line.