System checking and troubleshooting package for an electronic metering device
AssigneeSchlumberger Industries
InventorsForrest W. Briese, Charles C. Hyder, John M. Schlarb, Christophe J. A. Fouquet, Coy S. Lowe
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Abstract
An integral electronic meter system diagnostics package including a microprocessor, storage memory, logic for automatically and periodically performing a pre-select series of system diagnostic tests, and recording any results which exceed predefined programmable thresholds, and display means for displaying error and/or diagnostic messages identifying selected diagnostic data and/or errors discovered in the meter tests during a predefined period.
Claims1
An apparatus for calculating the phase angle of at least one phasor relative to a selected base phasor in a multi-phase electrical system, the apparatus including:
- a microprocessor;
- memory storage means for storing accumulated digital values corresponding to the instantaneous voltage measured for the base phasor, X.sub.B ;
- memory storage means for storing accumulated digital values corresponding to the instantaneous value measured for another selected phasor X.sub.N ;
- logic for calculating, for a pre-defined period, the RMS values for X.sub.B and X.sub.N, denoted X.sub.B(RMS) and X.sub.N(RMS), respectively;
- logic for determining the product, P, of X.sub.B(RMS) and X.sub.N(RMS) ;
- logic for determining the average value, Q, of the product of the two sine waves corresponding to X.sub.B and X.sub.N ;
- logic for determining the average value, Y, of the product of the two sine waves corresponding to a shifted version of X.sub.B, denoted X.sub.B(-90), and X.sub.N ;
- logic for determining the phase angle .theta. equal to arccos (Q/P).
Dependencies are inferred from the claim text.