A control node enables distributed grid control. The control node monitors power generation and power demand at a point of common coupling (PCC) between a utility power grid and all devices downstream from the PCC. The control node can have one or more consumer nodes, which can be or include customer premises, and one or more energy sources connected downstream. The control node monitors and controls the interface via the PCC from the same side of the PCC as the power generation and power demand. The control can include adjusting the interface between the control node and the central grid management via the PCC to maintain compliance with grid regulations at the PCC.

A frequency converter and a method in a frequency converter. The frequency converter is adapted to drive an electrical load, wherein the frequency converter comprises a communications interface through which the frequency converter is adapted to receive external requests to change input power of the frequency converter, means adapted to hold one or more conditions for allowing to change the input power of the frequency converter, and processing means adapted to change the input power of the frequency converter upon receipt of the external request in the limits set by the one or more conditions. (FIG. 1)

A method and associated system for minimizing grid feedback of a PV park to an energy supply grid connected to a point of common coupling is disclosed, wherein the PV park has a plurality of inverters divided into groups. The method includes, for at least a first inverter of each group, determining a first parameter representative of a first coupling impedance between the first inverter and the point of common coupling and determining a second parameter representative of a second coupling impedance between the group containing the first inverter and the point of common coupling. The method further includes storing the first parameter and the second parameter in an operating control unit of the first inverter, and, in daytime operation of the PV park, feeding in reactive power by the first inverter depending on the first parameter, said reactive power corresponding to the magnitude of a reactive power drawn by the respective underlying first coupling impedance. The method also includes, in night-time operation, deactivating all the inverters of a group with the exception of the first inverter and feeding in reactive power by the first inverter depending on the second parameter, wherein the reactive power fed in corresponds to a magnitude of a reactive power drawn by the respective underlying second coupling impedance.

A controller performs a first control for controlling the power source power factor or a power source harmonic of the harmonic current such that an input power factor of at least one of a plurality of connection devices changes in a direction preceding the power source power factor in a case where the power source power factor changes in a lagging direction, and performs a second control for controlling the power source power factor or the power source harmonic such that the input power factor of at least one of the connection devices changes in a direction lagging behind the power source power factor in a case where the power source power factor changes in a leading direction.

A method for maintaining sufficient reactive current margin in a power system connected to a power grid includes receiving, via a power limiter system, a reactive current command and an upper reactive current limit for the power system. The method also includes determining, via the power limiter system, a reactive current margin signal as a function of the reactive current command and the upper reactive current limit. Further, the method includes generating, via the power limiter system, a power command signal based on the reactive current margin signal. Moreover, the method includes controlling, via a system controller, operation of the power system based at least partially on the power command signal.

Enhanced network power factor corrective designs are presented that can use corrective devices that achieve long-term, operationally stable mechanical work. Embodiments can utilize reverse-winding induction motor designs with engineerable parameters and configurations for the reverse winding (13) in systems and through methods where an inductive motor (1) can present a current that leads voltage and a leading power factor (16) to correct other existing induction motors (8) in an initial network (9) or be optimized for a particular application. Designs also present a power factor correction that can present a variable correction without altering the character or physical capacitive value of an electrical correction component. Individual induction motors that have leading current and a leading power factor (16) can be provided to improve reverse winding induction motors. Progressive start controls (23) can also be used in a manner that limits inrush current to operational levels with passive current establishment control where reverse winding (13) effects can be used and perhaps even delayed to passively limit and even effect a current decrease while rotational acceleration continues after initial start transition.

A lighting network for altering a power factor of an alternating current, AC, supply (5). The lighting network comprises luminaires (2, 3) having reactive components of a first reactive type which are controllably coupled, by a controller, to the AC supply so as to adjust the power factor of the AC supply. The controller controls the coupling of the luminaires based on a power factor signal indicative of a power factor of the AC supply, which is influenced by an appliance (6) with a reactive load of a second reactive type, which appliance is different to any one of the luminaires. Preferably, the first reactive type is capacitive, and the second reactive type is inductive.

A power control system for managing energy transfer includes a shared electrical bus including an electrical energy generating source, an electrical energy storage device, and an electrical load, each connected to the shared electrical bus; and a controller operable to execute a plurality of instructions stored in a non-transitory memory on the controller to: receive a command corresponding to a desired operation of the power control system, generate a plurality of control commands as a function of a signal received from at least one sensor, and generate a log storing the present operating state for each of the electrical energy generating source, the electrical energy storage device, and the electrical load over a predefined duration, and wherein the at least one input corresponding to the past operating state of the power control system is the log.

Provided is a hybrid control device for a static synchronous compensator (STATCOM), the device including: a first arithmetic operation unit calculating the deviation between a reference voltage desired to be controlled by the STATCOM and output voltage to be output so as to output the same; a proportional integral (PI) controller performing PI control on the deviation output from the first arithmetic operation unit within a range between a new inductive reactive current maximum value and a new capacitive reactive current maximum value, so as to output a reactive current output value; and a second arithmetic operation unit adding the preset reactive current set value to the reactive current output value output from the PI control unit so as to output a reactive current reference value.

A wind turbine system is configured to supply real and reactive power to a grid and includes a tower, and a generator within a nacelle configured atop the tower. The generator is connected to a rotor, which is connected to a hub that includes a plurality of turbine blades mounted thereon. A power converter is configured at a location within the tower. A reactive power compensation device is also configured at the location within the tower, the reactive power compensation device operably configured with the power converter so as to provide reactive power in combination with reactive power generated by the power converter.