An electrical power system of a wind turbine is provided. A power converter of the wind turbine is configured to convert electrical power generated by an electrical generator of the wind turbine and to provide the converted electrical power to a power grid. The electrical power system includes an inductor unit coupled between a grid side converter section of the power converter and the power grid. Electrical power provided by the power converter towards the power grid causes a voltage drop across the inductor unit. The power system further includes an inductance adjustment unit coupled to the inductor unit. The inductance adjustment unit is configured to adjust an inductance value of the inductor unit to thereby adjust the voltage drop across the inductor unit.

The present invention provides a system for managing power in an electrical power distribution network. The system includes a plurality of DC/DC converters each electrically coupled between the output of one of a plurality of DC sources and a DC bus, the converters electrically coupled to the DC bus in parallel and each converter configured to transfer power from the DC source to the DC bus; at least one DC energy storage apparatus electrically coupled to the DC bus; at least one DC/AC inverter having an input electrically coupled to the DC bus and an output electrically coupled to at least one of an AC load and an AC electrical source; and, one or more electronic processing devices that selectively controls the DC/DC converters to thereby selectively control transfer of power to the at least one energy storage apparatus.

Management of an electrical power transmission network is obtained by providing at each subscriber premises a power correction system for applying a switched reactor for voltage correction across the input voltage and a sensing system defined by a pair of meters one at the supply and the second downstream of the voltage correction for detecting variations in power factor. The system includes an arrangement for balancing loads between a first phase on a first BUS and a second phase on a second BUS by calculating a required correction current by adding load currents from the first and second phases. In addition an arrangement is provided when a load is switched on and off power is supplied by or supplied to a battery for a short time and this power is reduced over a time period substantially matching or greater than said natural time constant of the power supply system.

An apparatus, such as an adjustable frequency drive (AFD), includes an inverter configured to be selectively coupled to a motor in a first mode and an AC line in a second mode and a control circuit configured to operate the inverter as a motor drive in the first mode and as a power compensator in the second mode. The power compensator may provide power factor correction. The control circuit may include a scalar controller configured to control the inverter according to a voltage vs. frequency characteristic determined by a field weakening point reference and the control circuit may vary the field weakening point reference in the second mode. The inverter may have an input coupled to a DC bus and the control circuit may be configured to adjust a frequency of the inverter in the second mode to increase a voltage on the DC bus.

The present invention provides a power-system stabilization system and a power-system stabilization method, which fundamentally solve the problems of insufficiency and fluctuation in the voltage maintenance capacity and the frequency maintenance capacity. A power-system stabilization system of the present invention comprises a synchronous machine to be field-regulated disposed in an electric power station connected to a power system, a magnetic field regulator for controlling the synchronous machine, and a compensation circuit for correcting a control constant of the magnetic field regulator in accordance with a power-system stability maintaining index that is an index reflecting a renewable energy amount in the power 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.

Systems and methods regarding distributed energy resource systems (DERs) are described. Configurations and employed methods may include sending a command to a DER system to place the DER system in one or more of a charge state, a discharge state, an idle state, or a reactive power state. These DER systems may include an energy storage circuit, a dc/ac converter configured to receive a DC voltage from the storage circuit and convert the received DC voltage for receipt by an external AC circuit, and one or more controllers configured to designate operation state of the storage circuit in at least a charge state, a discharge state, and an idle state.

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.

Management of an electrical power transmission network is obtained by providing at each subscriber premises a power correction system for applying a switched reactor for voltage correction across the input voltage and a sensing system defined by a pair of meters one at the supply and the second downstream of the voltage correction for detecting variations in power factor. The system includes an arrangement for balancing loads between a first phase on a first BUS and a second phase on a second BUS by calculating a required correction current by adding load currents from the first and second phases. In addition an arrangement is provided when a load is switched on and off power is supplied by or supplied to a battery for a short time and this power is reduced over a time period substantially matching or greater than said natural time constant of the power supply system.

The invention provides reactive power control equipment that controls the reactive power adjusted by a synchronous condenser coupled to an electric power grid and the reactive power of the electric power supplied to the electric power grid, to optimally control the reactive power in each load terminal point (power consumption area), considering instability of the electric power supplied from renewable energy power generation equipment. The above equipment includes an input portion that inputs information of reactive power including reactive power adjusted by an automatic voltage regulator of automatically adjusting a voltage of electric power generated by an electric power generator and supplied to an electric power grid, reactive power adjusted by a synchronous condenser coupled to the electric power grid, reactive power of electric power generated by the renewable energy power generation equipment, and reactive power set in each load terminal point (consumer area) of consuming the electric power; a calculation unit that calculates each setting value of reactive power adjusted by the synchronous condenser and the automatic voltage regulator, using the information of the reactive power input in the input portion; and an output portion that outputs the setting values of the reactive power calculated by the calculation unit respectively to the synchronous condenser and the automatic voltage regulator.