A plurality of active filter devices (41, 42, 43) that each have an output connected to a harmonic-generating load device (2) and are capable of generating a compensating current for performing at least one of reduction of a harmonic current of the harmonic-generating load device (2) and improvement of the power factor of the fundamental wave are provided. The plurality of active filter devices (41, 42, 43) provide two or more types of capacities, and the number and combination of operating active filter devices among the active filter devices (41, 42, 43) change in accordance with the magnitude of the compensating current.

A method for generating an inductive reactive power for a public grid by an electrical load apparatus, in which, in a first operating mode of the electrical load apparatus, an alternating current of the public grid is transformed by a transformer device and the transformed alternating current is provided for an electrical load of the electrical load apparatus. In a second operating mode of the electrical load apparatus that is different from the first operating mode, the transformer device is short-circuited in a phase-controlled manner by a switching device of the electrical load apparatus, wherein the switching device is phase-controlled such that, depending on a phase angle of the phase control of the switching device by the transformed alternating current, the inductive reactive power for the public grid is generated by the switching device.

Systems and methods for controlling and methods for controlling the power factor in a generator system are provided. In some embodiments, the generator system includes one or more generators configured to supply power to a power grid, an automatic voltage regulator configured to regulate a voltage of an output of the generator to a set voltage and regulate a power factor of the output to a set power factor, and a controller. The controller is configured to detect a fault on the output and to adjust the set power factor of the automatic voltage regulator based on the fault. The controller is further configured to ramp the set power factor from the adjusted value to an initial value over a set period of time.

An AC transmission system for a power transmission to an offshore plant. The AC transmission system includes an onshore power station which transmits an electric power, an offshore plant which receives the electric power, a submarine cable which connects the onshore power station to the offshore plant, and at least one pipeline with an electrical heating system which is connected to the onshore power station through the submarine cable.

A system and method for controlling power flow in a hybrid power system includes a controller in communication with the hybrid power system. The controller is also in communication with at least one knowledge system to receive information related to power generation or power consumption within the hybrid power system. The controller generates a control command for each of the power converters in the hybrid power system and maintains a log of power flow to and from each device in the hybrid power system. The controller is also in communication with a provider of the utility grid and may generate the control commands for each of the power converters in response to commands provided from the provider of the utility grid.

This disclosure is directed to a method for operating a wind farm having a plurality of wind turbines and to a control system for a wind farm. The wind farm is connected to an electrical grid. The wind turbines are operated to supply electrical power to the electrical grid in accordance with at least one setpoint value for a power related electrical variable. In the event that an available reactive power of the wind farm is smaller than a setpoint for a reactive power to be supplied by the wind farm, a required increase of reactive power is determined for each wind turbine of the wind farm.

Distributed grid intelligence can enable a virtual power grid. Multiple consumer nodes can have local power sources, and be coupled to a same point of common coupling (PCC). The consumer nodes can be controlled by distributed control nodes at the consumer nodes. The control nodes control the distribution of power from the local power sources based on local power demand of each respective consumer node, and also based on distribution of power from the other respective control node. Thus, consumer nodes can share power generated locally, but operate independently without the need for central management or a central power plant.

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.

The disclosed system provides an adaptive control system technique generally related to distributed energy resources (DERs) located in distribution circuits. More specifically, the system technique relates to a DER with both active and reactive generation capability. In an embodiment, the system measures a voltage phase angle and a current phase angle of distribution feeder circuit, and measures a voltage value output by a power converter. The system calculates an active power setpoint value and a reactive power setpoint value of the power converter based on the measured voltage value, and the measured voltage phase angle and current phase angle. The system then sets the active and reactive power setpoint values on the power converter. The disclosed system automatically adjusts the setpoints to real-time load characteristics of the distribution feeder circuit, increases distribution feeder hosting capacity, and enables DERs to integrate in distribution feeders more efficiently.

A method for controlling a power system includes generating, via at least one inverter-based resource, one or more command signals via a regulator of at least one inverter-based resource of the power system. Further, the method includes dynamically estimating, via the at least one inverter-based resource, a reactive power capability of the at least one inverter-based resource based, at least in part, on the one or more command signals. Further, the method includes sending, via the at least one inverter-based resource, the reactive power capability to the system-level controller. Thus, the method includes controlling the power system based on the reactive power capability.