Abstract: A method of power quality monitoring includes: capturing a power quality event; determining that the captured power quality event is one of a voltage sag, a swell or an interruption; in response to determining the captured power quality event is one of the voltage sag, the swell or the interruption, selecting a pre-event interval and a post-event interval; comparing a pre-event load level and a post-event load level; and detecting a load loss based on a result of the comparison.

Abstract: Systems, methods, and data structures for providing a file system with object versioning support are provided. Rather than adding object records for each version of an object to a chapter record, in one example, the chapter record may be limited to a single object record for the object including: (i) an object name of the object; (ii) an object file handle identifying an index of a file containing data of a current version of the multiple versions of the object; and (iii) a version table file handle identifying an index of a file containing a version table. In this manner, enumeration of objects associated with a given chapter may be performed more efficiently and prior versions of objects may be maintained within the version table without disproportionate growth of chapter records and without increasing the search depth with objects that are not referenced by the search at issue.

Abstract: Caching of data requests in session-based environment. An embodiment of a method includes a client preparing a data request for a storage server in a session-based environment. The prepared data request is transmitted from the client to the storage server. The data request is stored in a cache memory for the client via a protocol for the session-based environment.

Abstract: Caching of data requests in session-based environment. An embodiment of a method includes a client preparing a data request for a storage server in a session-based environment. The prepared data request is transmitted from the client to the storage server. The data request is stored in a cache memory for the client via a protocol for the session-based environment.

Abstract: Dynamic thresholds statistically derived are used to define normal conditions at a specific site in an electric power distribution system. High and low and/or caution and alarm thresholds for various parameters are generated as multiples of the standard deviation of the long-term average of measured values calculated from samples gathered over repetitive intervals, such as ten minutes. Weekly averages are used until sufficient data has been gathered to maintain a running one year average.

Abstract: A composite power quality indication generated from user weighted statistical contributions of selected system parameters provides an overall indication of power quality in an electric power distribution system. The user defined weightings are maintained over time by continually updating sensitivities that normalize the component contributions to the composite power quality indication. The current composite power quality indication is displayed in relation to its long-term mean and to dynamic thresholds determined as multiples of the standard deviation of the long-term mean.

Abstract: A method compensates for phase differences between sampled values of first and second AC waveforms. The method employs a phase angle compensation factor and sequentially samples a plurality of values of each of the waveforms. For a positive compensation factor, second sampled values are adjusted to correspond with first sampled values by employing, for a corresponding second sampled value, a preceding second sampled value plus the product of: (i) the compensation factor and (ii) the difference between the corresponding second sampled value and the preceding second sampled value. Alternatively, for a negative compensation factor, the second sampled values are adjusted by employing, for the corresponding second sampled value, the preceding second sampled value minus the product of: (i) the sum of one plus the compensation factor and (ii) the difference between the preceding second sampled value and the second sampled value preceding the preceding second sampled value.

Abstract: An electronic apparatus, such as a meter, includes an enclosure having a first housing portion with an opening and a second front plate portion. Meter circuitry is mounted within the enclosure. The second front plate portion mates with the first housing portion within the opening and forms an interface joint. The housing and front plate portions are at least substantially co-planar proximate the interface joint and include a plurality of mating crenellations. These mating crenellation, such as serrations, reduce electromagnetic interference radiation to or from the enclosure when the housing and front plate portions are mated together.

Abstract: A meter for power lines includes first input channels having AC signals with DC values of about zero. A second input channel has an analog output with a predetermined non-zero DC bias value. Plural biasing and scaling circuits input the AC signals and output corresponding analog outputs. Plural analog-to-digital converters input the corresponding analog outputs and output corresponding digital values. A serial output circuit serially communicates the corresponding digital values for a first set of A/D conversions before serially communicating digital values for a subsequent second set of conversions without providing any synchronization of the corresponding digital values for both the first and second sets of conversions. A serial input circuit serially receives the serially communicated digital values and saves the same in a memory. A processor averages the digital values for the channels and determines whether only the average associated with the second channel has the DC bias value.

Abstract: A monitor/analyzer for an alternating current (AC) electrical system responds to power line disturbances by generating a trigger signal when a change in voltage with respect to time electrical parameter is greater than a programmed threshold. The monitor/analyzer includes a sensor for sensing an AC waveform in the electrical system, an analog-to-digital converter for sampling the AC waveform, and a microcomputer. Firmware of the microcomputer cooperates with the A/D converter and provides a plurality of digital samples of the AC waveform for each of some of its AC cycles. The firmware generates each of plural dV/dt parameters of the AC waveform from a corresponding adjacent pair of the digital samples within one of the waveform's AC cycles. A trigger signal is generated when one of the dV/dt parameters is greater than the programmed threshold. The digital samples of the AC waveform before and after the power line disturbance are captured and output to a display in response to the trigger signal.

Abstract: A monitor for an ac electrical system generates on-line a display presenting the values, either in magnitude or as a percent of the fundamental, of 50 harmonics of any of the currents and voltages in the system. The display also incudes the phase angle of each harmonic relative to a reference waveform, which is preferably phase A-B voltage or phase A to neutral voltage.

Abstract: A monitor/analyzer for an ac electrical system can be programmed through a display on the front panel to respond to selected events by generating triggers signals when selected monitored electrical parameters including neutral current exceed programmed thresholds. The trigger signals initiate simultaneous waveform capture of multiple waveforms in the ac system. Multiple trigger signals result in sequential waveform capture so that if a plurality of triggers are programmed for the same event, extended waveform data is captured for the event. Alarm screens are generated in response to the events, as well as for hardware failure, an excessive neutral-to-ground voltage or reverse sequence.

Abstract: Apparatus for monitoring electrical parameters in an electrical system includes a display on which values of the various monitored electrical parameters are displayed, several at a time. The apparatus can be programmed to generate a custom display presenting selected ones of the many parameters, such as the ones most often referenced by the operator, so that it is not necessary to scroll through the large number of parameters to find those of frequent interest.

Abstract: An extraneous frequency detector especially suited for analyzing the three-phase output of a variable speed constant frequency (VSCF) generator generates in a sample-and-hold circuit amplitude samples of a phase selected by a multiplexer for application to a discrete time analog filter in the form of a switched capacitor high pass filter. A control circuit generates dual-phase non-overlapping clocking signals which control the sampling rate of the sample-and-hole circuit and the switching rate of the switched capacitor filter. Two modes of operation are provided for the single filter circuit by generating the clocking signals for the first mode of operation at a first frequency which is at least twice the frequency of the highest order harmonic of interest such that all frequencies above the fundamental are detected. In the second mode of operation, the clocking signals are generated at the fundamental frequency.

Abstract: Supports for mobile homes having a base, an intermediate vertical support fixedly secured to the base, and an upper mobile home support adjustable mounted at the upper end of the vertical support with means thereon for connection to the underside of a mobile home.