A system and a method for locally controlling delivery of electrical power along the distribution feeder by measuring certain electricity parameters of a distribution feeder line using a substation phasor measurement unit (PMU) electrically coupled to a substation distribution bus at a first node on the feeder line, and at least one customer site PMU electrically coupled to a low voltage end of a transformer at a customer site, wherein the transformer is coupled by a drop line to a second node on the distribution feeder line and the customer site is coupled by another drop line to the transformer, and by controlling at least one controllable reactive power resource and optionally a real power resource connected to the second node or at the customer site. Related apparatus, systems, articles, and techniques are also described.

A method of determining one or more direct voltage reduction (DVR) factors at a point of load (POL) in a power grid voltage environment. An energy processing unit (EPU) is installed at each individual POL; each EPU includes at least one AC-AC series voltage regulator. An EPU-regulated output voltage is increased under specific controlled conditions. One or more independent DVR factors for each individual POL are determined during the increased and decreased EPU-regulated output voltage.

Various embodiments of the teachings herein include a grid influencing system for a power supply grid comprising: a current-conducting grid influencing component; and a vacuum circuit breaker including a vacuum circuit breaker tube containing an at least partly integrated pre-arcing device for actively generating an arc between two contacts.

Wind turbine comprising a plurality of converters, which are dynamically switched between at least a first standby state, a second running state, and a third state with an active direct current link. Converters are switched from the first standby state to the third state when a required reactive power is higher than a reactive power capability of converters on the second running state and when a voltage transient occurs.

Provided in the present application are a compensator, a control method and device therefor. The compensator comprises: a first inverter, comprising six branch circuits, the branch circuits comprising combined power units and reactors connected in series; the combined power units comprising: first power units and second power units connected in series or second power units connected in series; a first transformer, at least comprising a first side winding and a second side winding, the first side winding being connected to an alternating current-side interface of the first inverter, the second side winding being connected in series to a circuit of an alternating current system; the second side winding being connected in parallel on either end to a switch; and the switch, connected in parallel to the first transformer and then connected to the circuit of the alternating current system.

In prior art grid systems, power-line control is done by substation based large systems that use high-voltage (HV) circuits to get injectable impedance waveforms that can create oscillations on the HV power lines. Intelligent impedance injection modules (IIMs) are currently being proposed for interactive power line control and line balancing. These IIMs distributed over the high-voltage lines or installed on mobile platforms and connected to the HV power lines locally generate and inject waveforms in an intelligent fashion to provide interactive response capability to commands from utility for power line control. These IIMs typically comprise a plurality of impedance-injection units (IIUs) that are transformer-less flexible alternating current transmission systems interconnected in a series-parallel connection and output pulses that are additive and time synchronized to generate appropriate waveforms that when injected into HV transmission lines are able to accomplish the desired response and provide interactive power flow control.

A reactive power control method, a reactive power control device, and a reactive power control system are provided. The device includes: a communication interface, configured to receive a reactive power requirement command; an input interface, configured to acquire an electrical quantity parameter of a preset control point; a strategy calculation module, configured to calculate a target reactive power value meeting the reactive power requirement command based on the electrical quantity parameter, and allocate reactive power to be provided by a regulatable reactive device based on the target reactive power value; and an output interface, configured to send a command for providing the allocated reactive power to the regulatable reactive device.

A voltage compensation device according to an embodiment includes a power converter, series transformers and a controller. The controller includes a first coordinate transformation circuit, a first arithmetic part, a second coordinate transformation circuit and a second arithmetic part. The first coordinate transformation circuit generates a first output and a second output that are mutually-orthogonal by performing a rotating coordinate transformation of the normal-phase components of a three phase alternate current. The first arithmetic part calculates a system voltage based on a direct current component of the first output and generates a first compensation amount corresponding to a compensation voltage set to compensate a shift of the system voltage from a preset target voltage. The second coordinate transformation circuit generates a third output and a fourth output that are mutually-orthogonal by performing a rotating coordinate transformation of reverse-phase components of the three-phase alternating current. The second arithmetic part generates second compensation amount of a reverse-phase component of the system voltage based on a direct current component of the third output and a direct current component of the fourth output. The first arithmetic part generates the first compensation amount to cause the compensation voltage when the system voltage is within a prescribed range to be less than the compensation voltage when the system voltage is outside the prescribed range.

In prior art grid systems, power-line control is done by substation based large systems that use high-voltage (HV) circuits to get injectable impedance waveforms that can create oscillations on the HV power lines. Intelligent impedance injection modules (IIMs) are currently being proposed for interactive power line control and line balancing. These IIMs distributed over the high-voltage lines or installed on mobile platforms and connected to the HV power lines locally generate and inject waveforms in an intelligent fashion to provide interactive response capability to commands from utility for power line control. These IIMs typically comprise a plurality of impedance-injection units (IIUs) that are transformer-less flexible alternating current transmission systems interconnected in a series-parallel connection and output pulses that are additive and time synchronized to generate appropriate waveforms that when injected into HV transmission lines are able to accomplish the desired response and an provide interactive power flow control.

A control system of a wind power installation and/or a wind farm is provided. The control system has a plurality of operating modes and has an interface. The interface is configured for providing maximum adjustability of the wind power installation and/or the wind farm in critical power grid situations. The interface is configured to receive a signal of a power grid operator, as a result of which all of the plurality of operating modes are released and made available to the power grid operator.