A voltage stability monitoring device for monitoring the voltage stability of a system, the device including: an assumed change scenario calculation unit for predicting the output variation of a renewable energy connected to said system and calculating an assumed change time-series power flow state on the basis of said output variation; a time-series voltage stability calculation unit for calculating a node voltage change with respect to demand at each node of said system on the basis of said power flow state calculated by said assumed change scenario calculation unit and calculating a voltage stability indicating the relationship curve between said node voltage and reactive power; and a voltage stability improvement countermeasure search unit for determining a controlled device on which an assumed control is to be performed, according to said voltage stability calculated by said time-series voltage stability calculation unit.

Example implementations described herein are directed to detection of anomalous events and locations on the transmission power system using phasor management unit (PMU) data, which provides information to grid operators for online decision support. From the high-resolution time synchronized PMU data, the transient abnormal events can be monitored and locations can be disclosed to operators for remedy actions. Utilization of PMU information for such decision support compliments operation practices relying on supervisory control and data acquisition (SCADA) measurements at much lower data resolution. Accurate identification of event locations can further advise grid operators the root cause of disturbances and illuminate possible cascading failures. Implementations of the proposed technology may improve the resilience and reliability of the transmission power systems.

Provided are a system frequency measurement method, synchrophasor measurement method and device. The synchrophasor measurement method comprises: sampling voltage and current signals based on an absolute time reference; removing out-of-band interference in the sampled voltage and current signals; first-resampling at least one of the voltage and current signals with the out-of-band interference being removed based on an estimated system frequency; calculating phasor for the signals obtained from the first resampling and updating the estimated system frequency; for a reporting timing, second-resampling the voltage and current signals with the out-of-band interference being removed based on the updated estimated system frequency; and calculating synchrophasor of the voltage and current signals obtained from the second resampling. The system frequency measurement method, synchrophasor measurement method and device are not only applicable to the stable operation of power systems but also to the dynamic operation thereof, and provide measurement result with high precision.

The present invention relates to a method for measuring the frequency of phasor of a power system, belonging to the technical field of power systems and automation thereof. A grid-connected photovoltaic generation system is provided with a control module, a data buffer module, an inverter, a sampling module and an analog-to-digital conversion module; a voltage transformer is connected to the grid side of the grid-connected photovoltaic generation system; the voltage transformer is electrically connected to the analog-to-digital conversion module; the analog-to-digital conversion module converts an analog signal sent by the voltage transformer into a digital signal; the sampling module samples the digital signal and transmits the digital signal into the data buffer module; the data buffer module is provided with a plurality of data windows; and the control module receives signals from the data windows.

Embodiments disclosed herein relate to a battery energy storage system (BESS) that can be used to store energy that is produced by conventional sources (e.g., coal, gas, nuclear) as well as renewable sources (e.g., wind, solar), and provide the stored energy on-demand.

A method for identifying conditions that correlate with one ore more events related to operation of a power grid. The method includes the determining one or more distinguishing characteristics of a first chunk. The first chunk includes data elements relevant to operating a power grid. The method also includes determining whether a distinguishing characteristic of the first chunk correlates with a distinguishing characteristic of one or more of a plurality of second chunks. Each second chunk includes a plurality of data elements corresponding with the data of the first chunk. The method further includes determining whether a second chunk, having a distinguishing characteristic equivalent to a distinguishing characteristic of the first chunk, is associated with the one or more events. In addition, the method includes determining whether a second chunk, having an association with the one or more events and a distinguishing characteristic equivalent to a distinguishing characteristic of the first chunk, is substantially identical to the first chunk.

A method determines voltages of buses of a power system. Values the voltages include a magnitude and a phase angle. The buses of the power system are grouped in a first area and a second area based on a type of measurement associated with each bus. The first area and the second area have at least one common bus, and wherein at least one bus in the first area is associated with a first type of measurement, and at least one bus in the second area is associated with a second type of measurement. Next, the method determines sequentially voltages of the buses of the first and the second areas.

Methods, systems, and computer program products for determining severity of a geomagnetic disturbance on a power grid using similarity measures are provided herein. A method includes extracting multiple features of activity associated with geomagnetically induced currents from multiple heterogeneous data streams; comparing the extracted features to historical data related to geomagnetically induced currents to determine a level of similarity between each of the extracted features and the historical data; assigning a level of severity to one or more of the extracted features having a level of similarity with the historical data above a given threshold; and generating a notification comprising (i) a prediction of activity associated with geomagnetically induced currents based on the extracted features having a level of similarity with the historical data above the given threshold, and (ii) the level of severity assigned thereto.

Methods, systems, and computer readable media are disclosed for maintaining photovoltaic power plant reactive power capability, e.g., through the manipulation of direct current (DC) voltage. In some examples, A control system includes a monitor input for receiving a monitor signal indicative of an input voltage of an inverter system and a control output for outputting a control signal to a voltage-clipping device of a solar panel system supplying a solar output voltage to the inverter system. The control system includes a control circuit configured to perform operations comprising: determining, using the monitor signal, that the input voltage of the inverter system exceeds a threshold voltage; and in response to determining that the input voltage of the inverter system exceeds the threshold voltage, causing, using the control signal, the voltage-clipping device to reduce the solar output voltage by shorting out one or more photovoltaic solar cells of the solar panel system.

An electric power system including an on-load tap changing (OLTC) transformer is provided. The OLTC transformer includes a primary winding and a secondary winding. A portion of the at least one primary winding and at least one of the secondary windings are inductively coupled to each other. Further, the electric power system includes at least one on-load tap changer coupled to the at least one primary winding or the at least one secondary winding of the OLTC transformer. The on-load tap changer is configured to regulate the portion of the at least one primary winding or the at least one secondary winding that are inductively coupled to each other. Furthermore, the system includes at least one controller coupled to the on-load tap changer. The controller is configured to determine a permissible voltage range defined by a bandwidth around a voltage set-point at the at least one on-load tap changer, where the bandwidth is a function of one or more electrical network states.