Waveform capturing arrangement in distributed power network

A method for measuring power-related waveforms respectively associated with branches, in a distributed power network using a monitoring unit coupled to each branch between a non-residential loadcenter and power equipment, wherein the power-related waveforms include zero-crossing which define their respective cycles and periods, which periods are susceptible to fluctuation in time, the method comprising the steps of:

• providing a plurality of monitoring units;
• disposing each of the plurality of monitoring units between the loadcenter and an associated power equipment;
• providing a control station communicatively coupled to the monitoring units;
• in each of said monitoring units
• (a) establishing an initial rate at which to sample the power-related waveform;
• (b) sampling the power-related waveform at the initial rate;
• (c) determining the period of the sampled power-related waveform;
• (d) selecting a number of integral cycles over which to sample;
• (e) based on the period of the sample power-related waveform and a predetermined number of sample points, computing a second rate at which to sample the power-related waveform;
• (f) at least once, sampling the power-related waveform over the selected number of integral cycles at the second rate and for the predetermined number of sample points and generating representative data therefrom;
• (g) transferring the generated data to the control station;
• (h) returning to step (c) so as to regularly and accurately sample the power-related waveform for the predetermined number of sample points over each selected number of integral cycles;
• and
• using the control station, evaluating the generated data transferred from each of said monitoring units.

A method for measuring a power-related waveform associated with a branch using a monitoring unit coupled to the branch between a non-residential loadcenter and power equipment, wherein the power-related waveform includes zero-crossing which define its cycles and periods, which periods are susceptible to fluctuation in time, the method comprising the steps of:

• providing a monitoring unit and disposing the monitoring unit between the loadcenter and associated power equipment and thereafter
• (a) establishing an initial rate at which to sample the power-related waveform;
• (b) sampling the power-related waveform at the initial rate;
• (c) determining the period of the sampled power-related waveform;
• (d) selecting a number of integral cycles over which to sample;
• (e) based on the period of the sample power-related waveform and a predetermined number of sample points, computing a second rate at which to sample the power-related waveform;
• (f) at least once, sampling the power-related waveform over the selected number of integral cycles at the second rate and for the predetermined number of sample points and generating representative data therefrom;
• (g) transferring the generated data;
• and
• (h) returning to step (c) so as to regularly and accurately sample the power-related waveform for the predetermined number of sample points over each selected number of integral cycles.

A circuit monitoring system which monitors power distributed to a plurality of powered equipment, wherein power-related waveforms are passed from a non-residential loadcenter to each of the powered equipment through a multitude of associated network branches and wherein zero-crossings of the waveforms define their respective cycles, the system comprising:

• a plurality of monitoring means, each of which is disposed adjacent an associated one of the branches and between the loadcenter and at least one of said power equipment, for sensing power parameters associated with the power-related waveforms and for generating and transmitting data representative thereof, each of said monitoring means including processing means for
• sensing the zero-crossings of the waveform,
• determining the period of the sample waveform,
• determining a number of integral cycles over which to sample the waveform as a function of the determined period,
• sampling the waveform 256 times over the number of integral cycles, and
• processing the sample waveform and generating representative data therefrom;
• and
• a control station, communicatively coupled to each of the monitoring means, for instructing each of the plurality of monitoring means to sample the associated waveform at an approximate time and for receiving and evaluating the representative data generated therefrom.

A circuit monitoring system which monitors power distributed to a plurality of powered equipment, wherein current and voltage waveforms are passed from a non-residential loadcenter to each of the powered equipment through a multitude of network branches, and wherein zero-crossings define the respective periods of the waveforms, the system comprising:

• a plurality of monitoring means, each of which is disposed adjacent an associated one of the branches and between the loadcenter and at least one of said power equipment, including
• sensing means for sensing power parameters associated with the power-related waveforms and generating analog signals representative thereof;
• a pair of analog to digital converters, each of which is responsive to at least one control signal, for converting the generated analog signals to digital signals which represent corresponding magnitudes of the analog signals;
• a demultiplexer, responsive to said at least one control signal, for coupling the generated signals to the pair of analog to digital converters;
• means for generating said at least one control signal to control the demultiplexer and the pair of analog to digital converters in an alternating manner so as to receive said digital signals at the processing means,
• means for estimating the magnitudes of the analog signals as though they were received in a non-alternating manner;
• and
• a control station, communicatively coupled to each of the plurality of monitoring means, for receiving power-related information therefrom which information pertains to a substantially simultaneous instant in time.