260 results about "Phasor measurement unit" patented technology

The relay system obtains voltage and current values from a power line and uses a first sampling element to sample the voltage and current values at selected intervals of time. The resulting sampled signals are used for power system-wide protection, control, monitoring and metering. The sampled signals are then resampled at a rate which is a selected multiple of the power system frequency. The results of the resampling are used by processing circuitry for protection functions including fault determinations.

Provided is a system for transmitting synchronized phasors over a wide area network. The system generally includes a plurality of phasor measurement units (PMUs). Each of the PMUs are associated with a secured portion of a power system and measure power system data from the secured portion of the power system associated therewith. The power system data is associated with a time-element. A power system data concentrator is further provided in communication with the phasor measurement units such that it aggregates and time-correlates the power system data. A server is further provided in communication with the power system data concentrator. The server includes a program for transferring the aggregated time-correlated power system data from the secured portion of the power system to a non-secure network.

A system for transmitting synchronized phasors over a wide area network. The system generally includes a plurality of phasor measurement units (PMUs). Each of the PMUs are associated with a secured portion of a power system and measure power system data from the secured portion of the power system associated therewith. The power system data is associated with a time-element. A power system data concentrator is further provided in communication with the phasor measurement units such that it aggregates and time-correlates the power system data. A configurable docking visualization tool or software is provided which communicates with the PMUs and data aggregators. The configurable tool provides an end user with the ability to dock or nest pre-configured forms for optimal viewing of synchronized phasor data and different power system quantities.

This invention relates to a PMU-based controlled system separation method to protect against a catastrophic blackout. The method includes the steps of performing an offline analysis of an electrical transmission network to partition generators into a number of coherent groups, performing online monitoring of the transmission network to determine a separation interface and frequencies and damping ratios of dominant inter-area modes, and estimating the risk of system separation to perform real-time control.

A state-matrix-independent dynamic process estimation method in real-time for weakly observable measurement nodes without PMU is only dependent on real-time measurement dynamic data of measurement nodes with Phasor Mesurement Unit (PMU) and measurement data of Supervisory Control And Data Acquisition (SCADA) system in electric power system or state estimation data. According to the SCADA measurement data or state estimation data at some continuous moments, the method utilizes recursive least squares solution to find a linear combination relationship between variation of measurement parameter to be estimated of nodes without PMU and variation of corresponding measurement parameter of nodes with PMU. Using the linear combination of relationship, the dynamic process of measurement nodes without PMU is estimated in real-time. The method provides high estimation precision and meets error requirements of engineering application.

The invention provides a bad data detection and identification method based on the measurement of a PMU (Phasor Measurement Unit) and the measurement of an SCADA (Supervisory Control and Data Acquisition). The method comprises the following steps: obtaining a network computing module by performing network topology analysis, detecting and identifying bad data based on an incidence matrix representing network topology relation, and detecting and identifying the bad data based on dynamic partition. The bad data detection and identification method based on the measurement of the PMU and the measurement of the SCADA is high in practical level, can be widely applied to current provincial power grids and national power grid, can adapt to requirement on online analysis of future large power grids, can rapidly and accurately remove bad data in measured information, and can improve mode estimation accuracy.

In one aspect, a computer system for managing occurrences of data anomalies in a data stream is provided. The computer system includes a processor in communication with the data stream. The processor is programmed to receive a first data stream from a phasor measurement unit. The processor is also programmed to calculate at least one singular value associated with the first data stream. The processor is further programmed to detect a first data anomaly within the first data stream using the at least one singular value. The first data anomaly occurs during a first time segment. The processor is also programmed to indicate the first time segment as containing the first data anomaly.

The invention relates to a two-end distance measuring method of transmission line fault under a dynamic condition, comprising the following steps of: acquiring two-end voltage and current signals through two-end phasor measurement units of the transmission line; then acquiring dynamic positive sequence impedance, admittance, wave impedance and propagation coefficients according to line parameter estimation and a dynamic line parameter method; and finally solving a nonlinear equation related to a fault distance according to the fact that positive sequence voltages derived from two ends to a fault point are equal by applying a Newton iteration method so as to obtain a dynamic distance measuring result of the transmission line fault. The two-end distance measuring method can more effectivelysolve the problem of line parameter and fault distance estimation under the dynamic condition and has accurate and reliable fault distance measuring result.

The invention concretely discloses a wide area measurement system which is applied to a phasor measurement unit and based on local frequency spectrum analysis, which comprises a WAMS main station, a PMU substation and a power data network; the PMU substation comprises a GPS time service unit, a synchronized phasor acquisition unit, and a data centralized processing unit; the WAMS main station sends measurement and configuration information, measurement information to be detected and thresholds of a plurality of low-frequency oscillation parameters and receives the parameters measured by low-frequency oscillation which exceed the thresholds and return from each PMU substation for comprehensive analysis in order to obtain overall oscillation mode information; the PMU substation also comprises a frequency spectrum analysis unit and a low-frequency oscillation detection unit. The invention also discloses a phasor measurement unit based on the local frequency spectrum analysis. The adoption of the system and device of the invention can realize real-time and rapid low-frequency oscillation detection and analysis of a large-scale electricity grid.

A method for determining an equivalent impedance of a transmission section of an electrical network, includes representing the transmission section as having at least two interfaces with other sections of the network. For each interface, a voltage phasor and a current phasor flowing through the interface are determined from simultaneously made measurements at the interfaces. From the phasors, the equivalent impedance is calculated. The required simultaneousness of the phasor measurements is achieved by means of Phasor Measurement Units (PMUs) that are synchronized via the Global Positioning System (GPS).

The invention belongs to the technical field of electric system operation and control, and particularly relates to an electric system state estimation method of a Phasor Measurement Unit-PMU based on an interpolation matrix. According to the method, during the updating interval period of SCADA measurement, a state, obtained through a PMU interpolation, of an area U is equivalent to prior state information of the area U, the prior state information is continuously updated at each sampling instant of the PMU, the interpolation matrix is updated when SCADA measurement and PMU measurement reach simultaneously at the next moment, and therefore the real-time running state of each node of the area U is worked out. The method has the advantages of being high in accuracy and sampling speed of PMU measurement, and can track the running state of the system accurately in real time.

Phasor Measurement Units (PMUs) tend to be specialized and expensive—relegated to only key points in power distribution networks, and are generally reliant on GPS technology. The present disclosure details how any smart meter—using wireless communication—can perform sub-microsecond-grade synchrophasor measurements. Other aspects concern smart meter-based determination of A, B or C phase of the tri-phase power network. This can involve count-stamp enabling message packets sent to and / or from a smart meter, and then associating such count-stamps to local measurements of power phase by a metrology unit. Once a network of such enabled smart meters and other devices is formed, sub-microsecond metropolitan-wide and entire region-wide synchronizing time standard can calibrate local measurements of power phase, where simple A, B and C phase determination is one low hanging fruit application of such. Low cost aggregate monitoring of metropolitan-wide synchrophasors promises a next chapter of importance for that relatively recent art.

The invention relates to a detection method of a phasor measurement unit (PMU), which comprises the following steps: firstly, establishing various needed waveform library based on the test items, then establishing a circuit diagram with a PSCAD tool and adjusting each parameter according to the test demands to form various waveforms; when in test, selecting a corresponding .seq file or a waveform file of a COMTRADE format according to the test items; playing back the .seq file or COMTRADE file by using an Omicron relay protection testing device; when in playback of the .seq file, setting a waveform playback time in the 'GPS Set' to play back the waveform in a prescribed moment; executing data acquisition by using a PMU, and then delivering messages to main station simulation tool software through a communication protocol; reading the protocol message in virtue of the PMU synchronized phasor data analysis software, and converting and storing the message into the amplitude and phase data; performing frequency analysis for a static measurement precision test; and finding the optimal range of device measurement precision.

The invention relates to an assessment method for transient voltage stabilization of a load area of an electrical power system and belongs to the electrical power system stability analyzing and assessment field. The assessment method for the transient voltage stabilization of the load area of the electrical power system includes that using data measured by a synchronous phasor measurement unit as basis, and building an initial sample database for data mining through a lot of simulation samples; extracting characteristics for reflecting the stabilization degree of each node through the quantitative evaluation for each node in the area; identifying through a multiple linear regression method to obtain sensitivity coefficients for reflecting the mutual influence relations between the nodes in a local area network; using a semi-supervised clustering method to demarcate all the samples; using a decision tree algorithm to perform classified learning to obtain a decision tree model, and using the decision tree model for online monitoring to assess the global transient voltage stabilization state of the load area of the electrical power system.

The invention provides a big data fault detection and positioning method for a power distribution network, and belongs to the field of intelligent power grids. The method comprises the steps: receiving voltage sampling data of the power distribution network through employing PMUs (Phasor Measurement Units); carrying out the preprocessing of voltages received by all PMUs, and constructing a receiving matrix; obtaining an unbiased estimated value of a receiving data covariance matrix through employing a random matrix theory; carrying out the eigenvalue decomposition of the covariance matrix, and obtaining a corresponding principal component; calculating a linear regression coefficient through employing PCA (Principal Component Analysis); comparing a relative approximation error and a threshold value, and achieving the fault detection and positioning of the power distribution network. The method provided by the invention solves a problem that the conventional covariance matrix estimation is biased under the measurement of a plurality of PMUs, and can achieve the real-time fault detection and positioning of the power distribution network.

The invention discloses a method and a device for dynamically testing a synchronized phasor measurement unit (PMU) in a power system. The method comprises the following steps: setting up a simulation model comprising a generator unit, a transformer, circuits, a load and an equivalent power grid on an RTDS (Real-Time Digital Simulator) platform; utilizing the simulation module to simulate the dynamic characteristics of the power system and detecting the PMU of the synchronized phasor measurement unit through real-time simulation tests. The method and the device are convenient to realize, the performance of the PMU can be correctly and reasonably detected and evaluated, and the further development of a PMU technology is better promoted. The test requirements of laboratories on the dynamic performance of the PMU are met, an effective means is provided for network access detection, the work requirements of manufacturers on product development, delivery inspection and the like are met, and the quality of the synchronized phasor measurement unit in the power system is specified and ensured. The method and the device have great meaning in improving the running reliability of the power grid.

The invention discloses a power system multi-zone distributed state estimation method based on a synchronous phase angle measurement device, which quickly estimates voltage amplitude values and phase angle values of all nodes of a power grid in real time by utilizing measurement data from a SCADA (supervisory control and data acquisition) system and a PMU (phasor measurement unit), and performs real-time interaction on state information of all zones. According to the method, a geographical characteristic-based non-overlapping decoupling strategy is adopted to decouple a large power system into subsystems, and states of all the subsystems are integrated by a coordination system; and with adoption of the multi-zone distributed state estimation method, estimation of states of the large system turns into estimation of states of a series of partial small zones, so that the computation speed is greatly improved. Real-time accurate measurement information of voltage, phase angle and the like can be offered to the system, and the system is enabled to obtain higher measurement redundancy, so that the accuracy of state estimation can be improved. According to the method, zone interaction management facilitates secure and effective access of new energy, so the development requirement of a future intelligent power grid can be met.

The invention provides a convolutional neural network power system intelligent fault detection method and system based on Spearman level correlation, and the method comprises the steps: setting a phasor measurement unit at a regional network node, and carrying out the measurement of data; performing Spearman correlation analysis on the acquired data, and proposing an image generation method basedon an analysis result; establishing an equivalent fault network, verifying the relation between the fault characteristics and the Spearman level correlation, and demonstrating the feasibility of the method; taking the generated image as an initial convolutional layer, and establishing a convolutional neural network architecture based on Spearman level correlation; and verifying the rationality andsuperiority of the method based on PSCAD / EMTDC according to the established architecture. A plurality of types of electric quantity data are comprehensively used for fault diagnosis, the position ofa fault in the power system can be quickly and accurately identified through the convolutional neural network, the problems that the power system has volatility and the traditional detection method isinaccurate due to addition of a distributed power supply and the like are solved, and the robustness and the self-adaptability of the power system are higher.

This is a nonlinear dynamic state estimation method based combined measurement by PMU and SCADA. A static module is established on the history data of SCADA. In case of non-measurement for part of nodes, conduct an accurate measure on adjacent nodes by PMU. An estimation on the non-measured nodes is made by Gauss-Seidel method.

In one aspect, a computer system for managing occurrences of data anomalies in a data stream is provided. The computer system includes a processor in communication with the data stream. The processor is programmed to receive a first data stream from a phasor measurement unit. The processor is also programmed to calculate at least one singular value associated with the first data stream. The processor is further programmed to detect a first data anomaly within the first data stream using the at least one singular value. The first data anomaly occurs during a first time segment. The processor is also programmed to indicate the first time segment as containing the first data anomaly.

The invention discloses a wide area measurement system based back-up protection method of a multi-terminal high-voltage power transmission area, belonging to the technical field of relay protection of electric power systems. In the method, the wide area measurement system based back-up protection of the multi-terminal high-voltage power transmission area and the synchronous real-time measurement on the voltage and current phasors of nodes provided with phasor measuring units are realized through adding centralized decision-making servers by utilizing the wide area measurement system of the multi-terminal high-voltage power transmission area, and a master station and a wide area back-up protecting server carrying out computation and analysis to accurately fix specific fault phases and fault line and issue control commands to execution substations of all lines in the area. The invention can make a decision within at most 200 milliseconds and sends the decision to every execution substation through adding the centralized decision making server and a remote control execution system, thereby realizing the wide area information based back-up protection of the multi-terminal high-voltagepower transmission areas and avoiding the fault of power failure in a large area due to protection misoperation after the fault occurs.

The invention discloses a phasor measurement unit (PMU) measurement data-based power line parameter identification and estimation method, and belongs to the technical field of power system line parameter identification and estimation. The method comprises the following steps of: inputting basic data of an identified and estimated line by using a computer through a program, identifying error parameters of the line according to the PMU measurement data of multiple time intervals at two ends of the line, and estimating accurate parameters of the line to acquire estimation values of the accurate parameters of the line. A mean value-based identification index and parameter estimation method is constructed by using the PMU measurement data of multiple time intervals at two ends of the line, anda variance coefficient is used as a convergence precision criterion; and the method is simple, has good identification effect, high estimation precision and high calculation speed, and is convenient for popularization and application. The method can be widely applied to identification and estimation of the centralized parameters of the power line, the two ends of which are provided with PMUs; andthe method is particularly suitable for identification and estimation of the parameters of medium length high-voltage and ultrahigh-voltage power transmission lines.

Phasor Measurement Units (PMUs) tend to be specialized and expensive—relegated to only key points in power distribution networks, and are generally reliant on GPS technology. The present disclosure details how any smart meter—using wireless communication—can perform sub-microsecond-grade synchrophasor measurements. Other aspects concern smart meter-based determination of A, B or C phase of the tri-phase power network. This can involve count-stamp enabling message packets sent to and / or from a smart meter, and then associating such count-stamps to local measurements of power phase by a metrology unit. Once a network of such enabled smart meters and other devices is formed, sub-microsecond metropolitan-wide and entire region-wide synchronizing time standard can calibrate local measurements of power phase, where simple A, B and C phase determination is one low hanging fruit application of such. Low cost aggregate monitoring of metropolitan-wide synchrophasors promises a next chapter of importance for that relatively recent art.

Phasor Measurement Units (PMUs) tend to be specialized and expensive—relegated to only key points in power distribution networks, and are generally reliant on GPS technology. The present disclosure details how any smart meter—using wireless communication—can perform sub-microsecond-grade synchrophasor measurements. Other aspects concern smart meter-based determination of A, B or C phase of the tri-phase power network. This can involve count-stamp enabling message packets sent to and / or from a smart meter, and then associating such count-stamps to local measurements of power phase by a metrology unit. Once a network of such enabled smart meters and other devices is formed, sub-microsecond metropolitan-wide and entire region-wide synchronizing time standard can calibrate local measurements of power phase, where simple A, B and C phase determination is one low hanging fruit application of such. Low cost aggregate monitoring of metropolitan-wide synchrophasors promises a next chapter of importance for that relatively recent art.

Exemplary embodiments of the present disclosure provide a method and controller for damping multimode electromagnetic oscillations in electric power systems which interconnect a plurality of generators and consumers. The controller for damping such oscillations includes a phasor measurement unit (PMU) and a power oscillation damper (POD) controller. Each oscillating mode signal is damped and then superposed to derive a control signal. A feedback controller is used to feedback the control signal to a power flow control device in the power system.

The invention relates to a technology for realizing insulation state on-line monitoring for high voltage electric power equipment in a substation under the architecture of a substation automation system (SAS), and discloses a method, a device and a system of insulation on-line monitoring for high voltage electric power equipment, which realizes synchronized phasor measurement by using a measurement unit at a spacer layer of the SAS and is realized by combining the internal communication of the SAS. The system comprises a monitoring main station at a station control layer, a synchronized phasor measurement unit (PMU) at a spacer layer, and a current synchronized phasor measurement unit (IPMU) which is locally installed dispersedly. The PMU and the IPMU realize the phasor measurement based on clock synchronization, and the PMU realizes the measurement at the spacer layer and the insulation on-line monitoring for main equipment; the IPMU measures the synchronized phasor of the leakage current of capacitive equipment and realizes the insulation on-line monitoring for the capacitive equipment by using the busbar voltage measured by the PMU; and the characteristic quantity of insulation monitoring adopts the variable quantity of leakage active power. The monitor main station, the PMU and the IPMU can also form a special insulation on-line monitoring system for the high voltage electric power equipment.

The invention belongs to the technical field of on-line detection and analysis for the low-frequency oscillation of an electric power system, and provides an on-line frequency band fast low-frequency oscillation detection and analysis method which aims at the wide area measurement system data and is applicable to a large-scale electric power system base on the empirical mode decomposition. The method of the invention not only has the strong adaptability to the non-linear and unstable complex waveform with non-periodic components, but also has synchronous and fast frequency spectrum analysis on the large amount of actual measurement curves of a phasor measuring unit can be realized through frequency band distribution, variable time window change and variable step, so that the fast detection and timely alarm to the low-frequency oscillation of various frequencies with different time periods can be realized.

The adaptive phasor measurement unit (PMU)-based series-compensated line (SCL) fault location method uses three different sets of pre-fault voltage and current phasor measurements at both terminals of the SCL. The three sets of local PMU measurements at each terminal are used for online calculation of a respective Thevenin Equivalent (TE). This enables representation of the power system pre-fault network with a reduced two-terminal equivalent system. The PMU measurements are also utilized for online calculation of the SCL parameters. This non-iterative method does not need knowledge of a time elapsed for the wave propagation from a fault point to a sending end and a receiving end. Two subroutines SA and SB are used for locating faults. A selection procedure is applied for indicating the valid subroutine and, hence, the actual fault location.

A real-time distributed wide area monitoring system is presented. The real-time distributed wide area monitoring system includes a plurality of phasor measurement units that measure respective synchronized phasor data of voltages and currents. The real-time distributed wide area monitoring system further includes a plurality of processing subsystems distributed in a power system, wherein at least one of the plurality of processing subsystems is configured to receive a subset of the respective synchronized phasor data, process the received subset of the respective synchronized phasor data to determine respective system parameters, wherein the plurality of processing subsystems are time synchronized.