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 wind farm, having a nominal power, for feeding electrical power into a supply network, comprising: wind power installations, a wind farm network and a stabilization unit connected to the wind farm network and arranged between the installations and the supply network. The stabilization unit increases a stability of the wind farm and comprises: an energy storage device which is set up to provide an electrical power, an intermediate circuit which is connected to the storage device and which is set up to conduct at least the electrical power provided by the storage device, an inverter connected to the intermediate circuit and set up to form at least the electrical power provided by the storage device, and a control unit set up to control at least the inverter such that the stabilization unit at the wind farm appears, statically as well as dynamically, like an electromechanical synchronous machine.

In a method for protecting lines, in which a reactor device for reactive power compensation is provided on an electrical line, a resonant current is measured on the line side of the reactor device by a first measuring device after an opening of a circuit breaker. A voltage is measured by a second measuring device after the opening of the circuit breaker. A current in the reactor device is calculated by an evaluation device on a basis of the measured voltage, and the calculated current is subtracted from the measured resonant current by the evaluation device in order to obtain a corrected current.

In order to output sufficient reactive power for voltage stabilization of a utility grid, and calculate an appropriate consideration according to an amount of the output reactive power, is provided a control device for controlling a distributed power source connected to the utility grid, comprising: a range setting unit where an allowable range of reactive and active powers output at normal times is set; an output control unit for controlling the reactive and active powers supplied from the distributed power source to the utility grid within the allowable range set in the range setting unit; and a reception unit for receiving, from a command device in the utility grid, an excess output command indicating that the reactive power exceeding the allowable range should be output, wherein the output control unit is for outputting the reactive power out of the allowable range when the reception unit receives the excess output command.

A power supporting arrangement includes a DC network having a first DC line with a first DC potential, a second DC line with a second DC potential, and an energy storage system that includes a first energy storage unit connected in a branch between the first and the second DC lines. A first group of phase arms is connected in a wye-configuration between the power grid and the first DC line and a second group of phase arms connected in a wye-configuration between the power grid and the second DC line. The first and second groups of phase arms are controllable as a voltage source converter. A third group of phase arms is connected to the power grid in a wye-configuration. The third group of phase arms have a neutral point and being controllable to support the power grid with reactive power.

A method for monitoring a three-phase network that is operated in a compensated manner for a tuning change of the arc suppression coil. Reference network parameters and a reference network frequency are determined for a tuned state, and a current network frequency is determined for a current state. A reference characteristic variable, which is proportional to a displacement voltage, is determined for the current network frequency using the reference network parameters, and a current characteristic variable, which is proportional to a displacement voltage, is determined at the current network frequency. A differential variable is determined from the reference characteristic variable and the current characteristic variable, from which, with a predetermined threshold value being exceeded, a tuning change is identified and changed network parameters are determined.

The present techniques generally concern methods and systems for monitoring and managing reactive power from horticultural lighting sources in an electrical grid. The techniques provided herein include determining or predicting distortive effects produced by the horticultural lighting sources, evaluating a power factor of the horticultural light sources, and based on a target power factor, adjusting the power factor of the horticultural light sources. The techniques described herein allow for an optimization of the power factor of the horticultural lighting sources in order to reduce, mitigate or eliminate the negative effects generally associated with the operation of horticultural light sources on the electrical grid.

A method and associated apparatus for feeding electric power from a photovoltaic system via a grid connection point into an AC grid having a low short-circuit power is disclosed. The method includes connecting a DC voltage side of at least one first inverter of the photovoltaic system to a photovoltaic generator and an AC voltage side of the at least one first inverter to the grid connection point, wherein the at least one first inverter is operated as a current source, and connecting an AC voltage side of a second inverter of the photovoltaic system to the grid connection point, wherein the second inverter is operated as a voltage source based on measurement values of an AC voltage measured in the region of the photovoltaic system and a predefined characteristic curve. For a first total short-circuit power of all first inverters operated as a current source, and a second total short-circuit power of the AC grid and of the second inverter operated as a voltage source, a ratio of the second total short-circuit power to the first total short-circuit power is greater than or equal to 2.

Systems and methods for managing loads on a power grid are provided. In some embodiments, the load control system includes one or more power sources connected to a power grid. A method includes determining, by a first genset connected to a power grid, a power average at a first rate, and generating, by the first genset, a filtered power average. The filtered average includes the power average at a second rate. The filtered power average is used in a second algorithm to balance the load share of power sources on the power grid.

Systems, methods, and devices are provided for controlling part of an electric power distribution system using an intelligent electronic device that may rely on communication from wireless electrical measurement devices. Wireless electrical measurement devices associated with different phases of power on an electric power distribution system may send wireless messages containing electrical measurements for respective phases to an intelligent electronic device. When wireless communication with one of the wireless electrical measurement devices becomes inconsistent or lost, the intelligent electronic device may synthesize the electrical measurements of the missing phase using electrical measurements of remaining phases. The intelligent electronic device may use the synthesized electrical measurements to control part of the electric power distribution system.