A method includes performing by a processor: receiving a plurality of synchrophasor measurements of a power system signal associated with a time interval from a plurality of phasor measurement units (PMUs), respectively, each of the plurality of synchrophasor measurements including a phase angle, frequency value, and a timestamp associated with the synchrophasor measurement; determining, for each of the plurality of PMUs, a dominant mode frequency of a forced oscillation signal component of the power system signal based on the frequency value and the phase angle; determining, for each of the plurality of PMUs, a mode angle of the forced oscillation signal component at the dominant mode frequency; and determining a geographic forced oscillation source location for a source of the forced oscillation signal component based on the plurality of mode angles associated with each of the plurality of PMUs, respectively, and geographic locations of the plurality of PMUs.

An electric storage device includes a first electric capacitor, a second electric capacitor, a converter, and a processor. The converter converts electric power transmitted between an external power system external to the electric storage device and at least one of the first electric capacitor and second electric capacitor. The processor is configured to control the converter to operate in at least one of a first mode and a second mode, the first electric capacitor continuously discharging electric power to the external power system in the first mode, the second electric capacitor discharging electric power to the external power system and being charged by the external power system, intermittently, to stabilize frequencies in the external power system in the second mode.

A method includes performing by a processor: receiving a plurality of synchrophasor measurements of a power system signal associated with a time interval from a phasor measurement unit (PMU), each of the plurality of synchrophasor measurements including a phase angle, frequency value, and a timestamp associated with the synchrophasor measurement, determining a plurality of relative phase angles based on the plurality of phase angles, determining a correlation coefficient between the plurality of relative phase angles and a plurality of corresponding frequency values of the power system signal, and detecting an error in the plurality of timestamps based on the correlation coefficient; estimating the error in the plurality of timestamps based on the plurality of relative phase angles and the plurality of corresponding frequency values.

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 for evaluating electrical phasors to identify, assess and mitigate selected power quality issues are disclosed herein. A method in accordance with one embodiment of this disclosure includes capturing or deriving at least one energy-related signal using one or more Intelligent Electronic Devices in an electrical system, and processing electrical measurement data from, or derived from, the at least one energy-related signal to identify anomalous characteristics in the electrical system. In response to identifying the anomalous characteristics in the electrical system, a degree of voltage phase jump and a voltage sag magnitude may be determined based on or using the identified anomalous characteristics. The degree of the voltage phase jump and the voltage sag magnitude may be displayed on at least one phasor diagram, and the at least one phasor diagram may be analyzed to determine most optimal/cost-effective apparatus(es) to mitigate at least one of the identified anomalous characteristics.

A voltage stability monitoring device and a method capable of obtaining information of voltage stability that can be served to practical use within a range of assumed conditions during a predetermined monitoring period are provided. The present invention provides a voltage stability monitoring device for estimating a voltage stability by using a voltage stability curve representing the voltage stability in an electric power system, including a voltage stability limit prediction unit for predicting a voltage stability limit, a voltage stability calculation condition determination unit for determining voltage stability calculation conditions by using a prediction result of voltage stability limit, a voltage stability curve calculation unit for calculating the voltage stability curve using a result of the voltage stability calculation condition determination, and a voltage stability margin calculation unit for calculating a voltage stability margin using a calculation result of the voltage stability curve.

A method includes performing by a processor: receiving a plurality of synchrophasor measurements of a power system signal associated with a time interval from a plurality of phasor measurement units (PMUs), respectively, each of the plurality of synchrophasor measurements including a phase angle, frequency value, and a timestamp associated with the synchrophasor measurement; determining, for each of the plurality of PMUs, a dominant mode frequency of a forced oscillation signal component of the power system signal based on the frequency value and the phase angle; determining, for each of the plurality of PMUs, a mode angle of the forced oscillation signal component at the dominant mode frequency; and determining a geographic forced oscillation source location for a source of the forced oscillation signal component based on the plurality of mode angles associated with each of the plurality of PMUs, respectively, and geographic locations of the plurality of PMUs.

Technologies for controlling forced oscillations in electrical power grids include a processing unit and a phasor measurement unit and a control device coupled to a power grid. The processing unit receives a measurement indicative of active power in the power grid from the phasor measurement unit and determines a frequency of a forced oscillation active in the power grid based on the measurement. The processing unit injects a corrective signal with the control device into the power grid. The processing unit determines a corrective phase and a corrective amplitude in response to injecting the corrective signal. The processing unit continues to inject the corrective signal with the corrective phase and the corrective amplitude. The control device may be a static VAR compensator, a synchronous generator, a static synchronous compensator, a synchronous condenser, an electric storage device, or a solar power plant. Other embodiments are described and claimed.

An impedance injection unit (IIU) system is coupled to a high-voltage (HV) transmission line. The IIUs are activated in sequences of activation in successive time periods. This injects an impedance waveform onto the HV transmission line. The ordering of IIUs in the sequences of activation is repeatedly changed in successive time periods. This equalizes electrical stress across the IIUs used, leading to overall improvement in IIU system lifetimes.

Embodiments of the present disclosure provide systems and methods directed to improved power system stabilization and oscillation damping control. In operation, a computing device may receive frequency data from a plurality of sensors distributed within a power system. The computing device may calculate an estimate of a speed of a center of inertia signal based at least on the frequency data. A controller may calculate a control error signal for the power system based at least on the estimated speed of the center of inertia signal. The controller may further calculate an auxiliary output signal based at least on the calculated control error. An actuator may utilize the auxiliary output signal to provide an output configured to improve the stability of the power system.