摘要:
A system and method of synchronizing measurements between a master monitor (130 and/or 132) and a slave monitor (154 and/or 164). A system controller (110) receives master samples representing a signal characteristic from the master monitor (130 and/or 132) and slave samples representing the signal characteristic from the slave monitor (154 and/or 164). The master samples and slave samples are aligned using correlation analysis to obtain the identification of a slave sample that aligns with a predetermined master sample. This identification is transmitted to the slave monitor and used to synchronize a master measurement with a slave measurement.
摘要:
Systems and methods for evaluating the stability of an islanded electrical system (off-grid) using high-speed frequency measurements of the electrical signal supplied by an alternate power source in the islanded electrical system. Additional inputs may include status signals from an automatic transfer switch, a generator, and loads within the islanded electrical system. The high-speed frequency measurements have a resolution sufficient to enable analysis of any combination of the frequency magnitude (e.g., sudden increase), frequency slew rate (e.g., frequency rate of change), frequency rate of recovery (e.g., frequency recovery time), or frequency oscillations (e.g., frequency ringing around the nominal value before settling) to indicate the presence of an actual or impending instability of the islanded electrical system. The frequency referred to herein corresponds to the frequency at which an alternating current supplied by the alternate power source is cycling.
摘要:
A method and system of converting numerical infrastructure data relating to a utility monitoring system having elements arranged in a hierarchy to a graphic compatible storage data format. Numerical infrastructure data relating to the elements of the utility monitoring system is obtained. The numerical infrastructure data relating to the elements of the utility monitoring system is converted to the graphic compatible storage data format. The graphic compatible storage data format may be System Specification Description (SSD). The converted data is stored in a storage file. A user interface may access the storage file to generate a graphic display showing the elements of the utility monitoring system arranged in the hierarchy.
摘要:
A method of automatically identifying whether intelligent electronic devices (IEDs) in a power monitoring system are in multiple electrical grids. A controller sends an instruction to each IED in a predetermined time sequence such that each IED receives the instruction at a different time, commanding each IED to begin logging frequency variation data in a current/voltage signal monitored by the IED and to send the data to the controller and an associated cycle count. The controller receives the variation data and associated cycle count and determines a peak correlation using a data alignment algorithm on IED pair combinations. If the IEDs are on the same electrical grid, the peak correlations should occur at cycle count offsets that match the order that the IEDs received the instruction. Any discrepancies in the expected order of peak correlations are flagged, and the corresponding IEDs are determined to be on different grids.
摘要:
A time synchronization device (TSD) that produces a synchronization signal and couples it onto energized power conductors in a power monitoring system. Monitoring devices coupled to the TSD include frequency detection algorithms, such as a Goertzel filter, for detecting the synchronization signal and interpreting the information encoded in the signal. The frequency of the synchronization signal may correspond to the fourth or tenth harmonic component of the fundamental frequency of the voltage on the power conductors. The magnitude of the signal is selected to be above the expected or established noise floor of the power monitoring system plus a predetermined threshold. The duration of the signal can be varied, such as lasting a full cycle of the fundamental frequency. Multiple TSD signals received in a predetermined sequence may be converted into digital words that convey time, configuration, reset, control, or other information to the monitoring device.
摘要:
A method and system of converting numerical infrastructure data relating to a utility monitoring system having elements arranged in a hierarchy to a graphic compatible storage data format. Numerical infrastructure data relating to the elements of the utility monitoring system is obtained. The numerical infrastructure data relating to the elements of the utility monitoring system is converted to the graphic compatible storage data format. The graphic compatible storage data format may be System Specification Description (SSD). The converted data is stored in a storage file. A user interface may access the storage file to generate a graphic display showing the elements of the utility monitoring system arranged in the hierarchy.
摘要:
A method for automatically determining how monitoring devices in an electrical system having a main source of energy and at least one alternative source of energy (e.g., another utility source, a generator, or UPS system) are connected together to form a hierarchy. The end-user inputs identification information about the monitoring device(s) monitoring the alternative source of energy. The method receives time-series data from the monitoring devices and determines a model type of the electrical system by analyzing the monitoring device's time-series data. Once the model type is known, the method builds the complete monitoring system hierarchy in which the monitoring devices that are monitoring the main and alternative sources are placed properly. The method can also validate polarity nomenclature of the time-series data to account for end-user's varying polarity configurations.
摘要:
A system and method to evaluate characteristics of transient events in an electrical power system to determine the location of a transient source type, the source type of a transient event, and suggested mitigation measures that might reduce or eliminate the effects of the transient. The electrical power system has a plurality of monitoring devices that each may detect the occurrence of a transient event incident upon the power system. A controller is coupled to the monitoring devices. The monitoring devices measure signal parameter values associated with the transient event, and the location of the transient event is automatically determined by evaluating transient characteristics from each of the recording monitoring devices. Other measurements of signal parameters may be made to determine transient characteristics. The transient characteristics may be used to determine the source of the transient event, the type of transient event, mitigation measures, and the effects or predictive effects of mitigation measures.
摘要:
A system for accumulating and evaluating electromagnetic phenomena of at least one power quality category of a power distribution system, using a circuit monitor or processing system that summarizes and trends electromagnetic phenomena. The system provides for expressing the power quality index as a single number for each power quality category present and for combining multiple power quality indices into a single overall power quality index.
摘要:
A method of automatically identifying an anomalous condition of an induction motor by normalizing the voltage measured across its terminals relative to the power flow to the motor or the motor's impedance. The starting and/or run current and associated voltage of the motor is measured, and a voltage variation between the measured voltage and the motor's rated voltage is determined. The power flow or impedance at the voltage variation is calculated to determine an expected power flow or impedance at the measured voltage variation. The actual power flow or impedance is compared against a nominal or expected power flow or impedance or a statistical comparison is carried out on a historical set of power flow or impedance values within an expected range at the voltage variation. When the measured values deviate from the expected ones, an alarm is triggered to indicate a potential anomaly with the motor or external thereto.