A distribution feeder of an electricity grid comprises a substation and a plurality of nodes with at least one controllable reactive power resource. A method is provided for locally controlling delivery of electrical power along the distribution feeder, wherein for a feeder segment in the distribution feeder the method comprises: obtaining an actual voltage magnitude at an upstream node and at a downstream node of the feeder segment, and a real power value at the upstream node; setting a target voltage phasor at the downstream node as a value when a power flow across the feeder segment is maintained, and when equal reactive power is injected at the upstream and downstream nodes that consumes all the reactive power in the feeder segment; and adjusting operation of the at least one controllable reactive power resource so that the actual voltage magnitude at the downstream node moves towards a target voltage magnitude of the target voltage phasor.

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.

An energy grid network includes multiple distributed energy resources (DERs) or DER nodes. A DER node includes a local energy source and a local energy load. The DER nodes in the network generate realtime data about energy availability from local energy sources and realtime data about energy demand. The DER nodes can share the realtime data with other DER nodes in the network to provide a constant view in the network about the energy generation and energy demand within the network. The shared realtime data can be scaled at each DER node based on physical distance, time to exchange energy between nodes, or both distance and time. A DER node generates its own realtime data and receives data from one or more other DER nodes and determines the value of energy use from local or non-local sources by local and non-local loads.

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.

The invention relates to a current-compensating device able to be connected, in shunt configuration, between an electrical network and non-linear and linear electrical loads and downstream of at least one renewable-energy-generating power unit coupled to an energy-storing element, the compensating device including: a power converting unit including at least one voltage inverter able to generate an AC current; an output filtering unit, including one filter dimensioned to block the harmonic components due to the switching of the inverter; a control unit comprising a unit for computing reference currents and a switch driving device that controls the switching of the inverter as a function of the identification of the currents by the unit for computing the reference currents.

Methods for black-starting an electrical grid (2) are described herein. For example, a method comprising disconnecting the wind farm (1) from the grid at a first location, said first location being located between the electrical grid (2) and the energy storage (16) with the associated converter (17), energizing the AC export cable (12) using said energy storage (16) and the associated converter (17), energizing at least one part of the wind farm electrical infrastructure via said export cable (12) using said energy storage (16) and the associated converter (17), re-establishing energy supply to said wind farm electrical infrastructure by said wind turbine generators (3, 4), and reconnecting the wind farm (1) to said electrical grid (2) at said first location.

An illustrative example fuel cell power plant includes a cell stack assembly having a plurality of fuel cells configured to generate electricity based on an electrochemical reaction. The power plant includes a capacitor, a plurality of inverters, and at least one controller that is configured to control the plurality of inverters in a first mode and a second mode. The first mode includes the cell stack assembly associated with at least one of the inverters. A cell stack assembly and the associated inverter provide real power to a load external to the fuel cell power plant in the first mode. The second mode includes at least a second one of the inverters associated with the capacitor. The capacitor and the second one of the inverters selectively provide reactive power to or receive reactive power from a grid external to the fuel cell power plant in the second mode.

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 power quality compensation system has the functions of controlling the bus voltage and the current peak value. A first instruction current under control of a first peak current processing unit is lower than or equal to a first current threshold value. A second peak current processing unit outputs a second PWM driving signal according to a sampled current and a second current threshold value. A third peak current processing unit outputs a third PWM driving signal according to the sampled current and a third current threshold value. A conversion unit is operated according to the PWM driving signals. Moreover, the first current threshold value is adjusted in real time according to the comparing result of the sample current and the first current threshold value and the comparing result of the real DC bus voltage and the reference DC bus voltage.

A power quality compensation system has the functions of controlling the bus voltage and the current peak value. A first instruction current under control of a first peak current processing unit is lower than or equal to a first current threshold value. A second peak current processing unit outputs a second PWM driving signal according to a sampled current and a second current threshold value. A third peak current processing unit outputs a third PWM driving signal according to the sampled current and a third current threshold value. A conversion unit is operated according to the PWM driving signals. Moreover, the first current threshold value is adjusted in real time according to the comparing result of the sample current and the first current threshold value and the comparing result of the real DC bus voltage and the reference DC bus voltage.