External transformer correction in an electricity meter
A method compensates for measurement errors of an external transformer coupled between an electricity meter and one or more power lines. The method includes a first step of obtaining at least one error rating for the external transformer. The method also includes the step of storing data representative of the at least one error rating in a memory within the meter. At some point the electricity meter is coupled to the external transformer. The method further includes the step of employing the meter to obtain at least one electricity consumption measurement value, the at least one electricity consumption value comprising either a sampled current value or a sampled voltage value. Finally, the method includes the step of causing the meter to adjust the at least one electricity consumption measurement value using at least a portion of the stored data.
1 . An arrangement for use in an electricity meter, the electricity meter operably coupled through an external transformer to measure electricity consumption on a power line, the arrangement operable to compensate for measurement errors, the arrangement comprising:
a) a source of digital measurement signals comprising an internal sensor circuit and an analog-to-digital conversion circuit, the internal sensor circuit configured to convert power line signals received from the external transformer to measurement signals, the analog-to-digital conversion circuit configured to receive the measurement signals from the sensor circuit and convert the measurement signals to digital measurement signals;
b) a memory storing data representative of at least one error rating for the external transformer;
c) a processing circuit operably coupled to the source of digital measurement signals to receive digital measurement signals therefrom; the processing circuit operable to
obtain at least one electricity consumption measurement value corresponding to at least a part of the digital measurement signals, and
adjust the at least one electricity consumption measurement value using at least a portion of the stored data.
2 . The arrangement of claim 1 wherein the at least one electricity consumption measurement value comprises a calculated energy consumption value.
3 . The arrangement of claim 1 wherein the at least one electricity consumption measurement value comprises at least one of a sampled current value or a sampled voltage value.