A circuit monitoring system for a distributed power network employs waveform capturing techniques for efficient and highly accurate monitoring. The system includes a plurality of circuit monitors and a control station, which is coupled to each of the circuit monitors via a multi-drop communications link. Each of the circuit monitors is disposed adjacent an associated one of the branches in the network for sensing power parameters in the branches and for generating and transmitting data represent...

A transmitter couples an output to a loop which represents a sensed process variable such as pressure. A microprocessor-based circuit in the transmitter senses the process variable and computes an output signal and provides the output to the loop. A communication circuit in the transmitter receives a high frequency signal including a transmitter parameter from the loop. The communication circuit couples the parameter to the microprocessor. The microprocessor couples the parameter to an EEPROM. T...

A motor performance analyzer senses currents and voltages applied to the motor, converts the sensed signals to digital data signals, and stores the digital data signals. The analyzer includes a processor for evaluating the digital data and a display for alerting a user or technician to potential motor problems, or to developing problems, including winding faults and broken rotor bars. Advanced signal processing techniques are used to further evaluate stored data and to provide trending informati...

A method and a device for monitoring instantaneous electrical parameters of a power distribution system under load utilizing digital control means. An analog signal equivalent to such a parameter is sensed and rated down for processing by solid state components. This signal is converted into a binary coded digital signal having n digits. A plurality of digital signals is sampled and squared values with a format of 2n digits are derived from each sample. The squared values of one sampling period ...

A method is described for metering electrical energy. The method includes sensing each phase of a circuit to generate analog voltage signals and analog current signals associated with each phase. The analog voltage signals and said analog current signals are converted into digital voltage signals and digital current signals, respectively, using time division multiplexing to provide three digital outputs. The digital outputs comprise at least one digital voltage signal and at least one digital cu...

Line voltage and line current signals are sensed on a power line having at least one conducting path. The sensed line voltages and line currents are converted into a digital signal. A phase-to-neutral voltage signal and phase current signal are computed from the digital signal to thereby define a phase of the power line. An interval of orthogonality is determined from the sensed voltage and current signals, coinciding with passage of an integral number of cycles of a fundamental frequency refere...

A power line ampacity system called LINEAMPS is invented by object oriented modeling and expert rules of the power line environment. Ampacity is estimated by the solution of conductor temperature differential equations using synthetic generation of meteorological data adjusted to national weather service forecast. The line ampacity system provides hourly values of present and future power line ampacity up to seven days in advance. The program has steady state, dynamic and transient ampacity mode...

A method of estimating the precision of an apparatus that generates a continuous stream of information. The method comprises dividing the information in successive or overlapping pairs and calculating an index of precision therefrom for evaluation against a benchmark such as a standard value, a specification, or a contract requirement. Calculations can be done by a microprocessor and microprocessor instructions internal to the instrument or by a microprocessor and microprocessor instruction exte...

Errors introduced into ac waveform measurements based on discrete amplitude samples because the waveform period is not an integral number of sampling intervals are substantially averaged out by computing the aggregate average of the set averages of sets of samples. Each set is taken over approximately an integral number of waveform cycles, and the set terminations are spread uniformly over approximately an integral number of cycles. Each set may overlap the previous set by all but one sample. As...

The faulted sections are evaluated by calculating the measuring information resulted from the faults in various positions by the previous fault simulative calculation, introducing the resulting fault simulative measuring information into a self-organizing neural network having output elements of which number being more than that of input elements to permit the self-organizing neural network to learn the classification of the simulative measuring information, preparing an evaluation rule represen...