Electrical circuit control techniques in power systems are disclosed herein. In one embodiment, a supervisory computer in the power system can be configured to fit phasor measurement data from phasor measurement units into a Gaussian distribution with a corresponding Gaussian confidence level. When the Gaussian confidence level of the fitted Gaussian distribution is above a Gaussian confidence threshold, the supervisory computer can be configured to perform an ambient analysis on the received phasor measurement data to determine an operating characteristic of the power system. The supervisory computer can then automatically applying at least one electrical circuit control action to the power system in response to the determined operating characteristic.

A load apparatus is connected to an AC power source and is supplied with power from the AC power source. An operation state control unit controls, based on a target value about a power-source quality including either a power-source power factor of the AC power source or a power-source harmonic of the AC power source and on a present power-source quality, an operation state of the load apparatus.

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.

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.

A method for voltage control of a static synchronous compensator, STATCOM, or a static var compensator, SVC, is presented. The method is performed in a control device. The method includes obtaining a synchronous condenser, SC, error, obtaining a STATCOM or SVC voltage setpoint, adjusting the obtained STATCOM or SVC voltage setpoint with the obtained SC error to a total STATCOM or SVC voltage reference, and providing the total STATCOM or SVC voltage reference for voltage control of the STATCOM or SVC. A control device and a computer program for voltage control of a STATCOM or an SVC are also presented.

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.

According to one aspect of the disclosure, a power filter is provided including a first input configured to receive measurements of electrical characteristics of source power lines from a power source, a second input configured to receive measurements of electrical characteristics of load power lines to a load, an output configured to couple to output power lines to provide output current compensation signals, a power converter coupled to the power output and configured to receive input power, receive input control signals and provide the output current compensation signals based on the input control signals, and a controller configured to provide the control signals to the power converter, wherein the controller receives an indication of a neutral current limit, and the controller is configured to adjust the control signals based on the indication of the neutral current limit to limit current on a neutral of the output power line.

The setting range of the voltage and the reactive power of a power system is maintained during variations of voltage and power flow due to the output variation of renewable energy of a large number of power supplies which fluctuate due to weather. A voltage/reactive power operation assisting device is provided with a first database for storing the data to be evaluated, target value data, individual control device control method data, and individual control device data of an individual control device for adjusting the voltage/reactive power of a power system. A second database stores the device operation data of the individual control device; and the operation of the individual control device is predicted from the data stored in the first database to obtain individual control device operation prediction data. A display unit displays the individual control device operation prediction data and the device operation data in a contrastive manner.

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 onto HV transmission lines are able to accomplish the desired response and an provide interactive power flow control.

Systems and methods are disclosed herein to a power factor adjustor comprising: a power factor measurement unit configured to measure the power factor on an input line to a load and generate a power factor correction signal based on the measured power factor; and a power factor adjustment unit connected to the power factor measurement unit comprising: a fixed capacitor connected in series to a first switching device; and an adjustable element having a variable capacitance connected in parallel to the fixed capacitor and in series to a second switching device, wherein the overall capacitance of the power factor adjustment unit is adjusted by adjusting the capacitance of the adjustable element or by toggling the first and second switching devices in response to the power factor correction signal.