A system includes a control unit having one or more processors and a communication interface. The communication interface is configured to communicate with one or more charging stations that are electrically coupled to receive electrical power from a power distribution grid and that are configured to selectively charge one or more energy storage devices connected to the charging stations. The one or more processors are configured to generate first control signals for communication by the communication interface to the one or more charging stations to control transfer of reactive and/or active power from the charging stations to the power distribution grid. The control signals are generated based at least in part on a load cycle profile of one or more electric machines electrically coupled to the power distribution grid.

A method includes obtaining a voltage phasor, a current phasor and a mechanical rotor angle of a source end generator. A receiving end generator impedance and a line impedance between the source end generator and a receiving end generator is also estimated. Furthermore, a swing angle between an internal voltage of the source end generator and an internal voltage of the receiving end generator as a function of obtained voltage phasor, current phasor, mechanical rotor angle and the impedances is estimated. A power swing condition is then determined based on the estimated swing angle.

Providing a power system and a method for stabilizing a system, in which the number of generators to be disconnected is reduced to narrow an area influenced by a grid fault in the case where the reliability of the state estimation calculation is judged to be high. The power system stabilizing method applied to a power system configured to include a plurality of feeders including circuit breakers, a plurality of nodes, a plurality of generators, and a plurality of loads, in which method: a protection relay detects a grid fault by using an output from a first sensor installed close to the circuit breaker, thereby opening-controlling the circuit breaker, and the circuit breaker is opening-controlled by a power system stabilization output; a state estimation value of a power system obtained by using the first sensor output and a state detection value, of the power system, containing information associated with measurement time measured in the power system are compared with each other to judge reliability of the state estimation value; the circuit breaker which is to be newly cut off from a viewpoint of power system stability after occurrence of a grid fault at a supposed grid fault point of the power system is stored, and the circuit breaker which is to be cut off every reliability judgment result of the state estimation value is stored; and at the time of occurrence of a grid fault of the power system, a turn-off command for the circuit breaker which is selected in response to the reliability judgment result of the state estimation value so as to be newly cut off is set as the power system stabilization output.

Systems, methods, and devices relating to operating a power generation facility to contribute to the stability of the power transmission system. A controller operates on the power generation facility to modulate real power or reactive power or both in a decoupled manner to contribute to the stability of the power transmission system. Real power produced by the power generation facility can be increased or decreased between zero and the maximum real power available from the PV solar panels, as required by the power system. Reactive power from the power generation facility can be exchanged (injected or absorbed) and both increased or decreased as required by the power transmission system. For solar farms, the solar panels can be connected or disconnected, or operated at non-optimal power production to add or subtract real or reactive power to the power transmission system.

This disclosure includes various systems and methods for determining an operating stage based on electrical conditions in electric power delivery systems and identifying a control strategy based upon the operating stage. The control strategy may be selected and customized to avoid or to ameliorate stresses in an electric power delivery system while maintaining the stability of electric power delivery systems. Various embodiments consistent with the present disclosure may include a distributed controller configured receive a plurality of indications of electrical conditions from a plurality of control devices in electrical communication with the electrical power delivery system. The distributed controller may determine an operating stage from among a plurality of operating stages based upon the plurality of indications of electrical conditions. The distributed controller may further identify a control strategy based upon the operating stage. The control strategy may be communicated to and implemented by the plurality of control devices.

Embodiments of the present invention include control methods employed in multiphase distributed energy storage systems that are located behind utility meters typically located at, but not limited to, medium and large commercial and industrial locations. These distributed energy storage systems can operate semi-autonomously, and can be configured to develop energy control solutions for an electric load location based on various data inputs and communicate these energy control solutions to the distributed energy storage systems. In some embodiments, one or more distributed energy storage systems may be used to absorb and/or deliver power to the electric grid in an effort to provide assistance to or correct for power transmission and distribution problems found on the electric grid outside of an electric load location. In some cases, two or more distributed energy storage systems are used to form a controlled and coordinated response to the problems seen on the electric grid.

A monitoring arrangement is described for monitoring a parameter value associated with an AC supply in a distribution network. The monitoring arrangement includes a sensor electrically connected, in use, to the network or otherwise monitoring the network, and a control unit operable to use the output of the sensor to determine a phase offset value relative to a predetermined phase offset value, and to use the difference in the phase offset values in controlling the operation of a load or device.

A voltage stability prediction system is configured to predict voltage stability of a power system under a contingency. The voltage stability prediction system in this regard may execute model-based contingency analysis using a model of the power system to predict, as of a first time, voltage stability of the power system post-contingency. The voltage stability prediction system also obtains, from phasor measurement units (PMUs) in the power system, synchrophasor measurements that indicate, as of a second time later than the first time, phasors in the power system pre-contingency. Further, based on the model-based contingency analysis and the synchrophasor measurements, the voltage stability prediction system predicts, as of the second time, voltage stability of the power system post-contingency.

This disclosure includes various systems and methods for determining an operating stage based on electrical conditions in electric power delivery systems and identifying a control strategy based upon the operating stage. The control strategy may be selected and customized to avoid or to ameliorate stresses in an electric power delivery system while maintaining the stability of electric power delivery systems. Various embodiments consistent with the present disclosure may include a distributed controller configured receive a plurality of indications of electrical conditions from a plurality of control devices in electrical communication with the electrical power delivery system. The distributed controller may determine an operating stage from among a plurality of operating stages based upon the plurality of indications of electrical conditions. The distributed controller may further identify a control strategy based upon the operating stage. The control strategy may be communicated to and implemented by the plurality of control devices.

A method for controlling a power output of a power generating unit includes receiving at least two measurement data sets from a location of integration of a power generating unit to an electrical grid. Each measurement data set includes a plurality of electrical parameters. The method further includes generating a grid model of the electrical grid based on the at least two measurement data sets. The grid model is characterized by an equivalent grid voltage and an equivalent grid impedance. The method further includes computing a strength value of the electrical grid based on the grid model, using the at least two measurement data sets. The method also includes controlling the power output of a power generating unit based on the strength value of the electrical grid.