Power meter calibrating system and power meter calibrating method for intelligent electric meter

Abstract

The invention aims to provide a power meter calibrating system and a power meter calibrating method for an intelligent electric meter. The power accuracy of a manganin sampling-based intelligent electric meter is improved in a mode of meter calibrating to ensure the high efficiency and consistency of quantity production. The meter calibrating system comprises a meter calibrating platform, an upper computer and a communication circuit connected with the meter calibrating platform and the upper computer, wherein the meter calibrating platform is provided with a power supply circuit for meter calibrating, a power error reading circuit and a meter calibrating data writing circuit. In the meter calibrating method, by adopting the meter calibrating scheme of two-point mixing, namely a real-time error value of the intelligent electric meter is read quickly under a heavy current point, and a real-time power value is read stably under a low current point, two meter calibrating parameters of a power gain value and a power biasing value of the electric meter are obtained through calculation by a corresponding algorithm, and the two parameters are written into the electric meter by utilizing meter calibrating data.

Description

technical field [0001] The invention relates to the field of electric energy measurement, in particular to a scheme for calibrating the power of an intelligent electric meter based on manganin-copper sampling. Background technique [0002] Driven by the popular smart grid all over the world, how to improve the measurement accuracy of smart meters has become a common goal in the electric energy measurement industry. [0003] Taking the meter based on manganese-copper sampling as an example, due to the consideration of power loss and system heating, the value of the manganese-copper resistance is generally micro-ohm level, so the current loop input signal to the AD sampling terminal is also relatively small (the small current point is only Tens of microamplitudes), such a weak signal is easily affected by external signals, resulting in large power errors at small current points. These effects come from the parasitic capacitance on the current sampling circuit, the magnetic flu...

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Problems solved by technology

[0003] Taking the meter based on manganese-copper sampling as an example, due to the consideration of power loss and system heating, the value of the manganese-copper resistance is generally micro-ohm level, so the current loop input signal to the AD sampling terminal is also relatively small (the small current point is only Tens of microamplitudes), such a weak signal is easily affected by external signals, resulting in large power errors at small current points. These effects come from the parasitic capacitance on the current sampling circuit, the magnetic flux leakage interference of the transformer, and the interference of the power supply circuit. If the DC offset introduced by these signal loops cannot be effectively processed, the accuracy of the small current point error and the linearity of the meter in the entire measurement range cannot be guaranteed.

[0004] The electric meter industry has always believed that the weak manganese-copper sampling signal leads to low measurement accuracy, so that the manganese-copper sampling scheme has always remained in single-phase meters for residential use and three-phase active meters with low precision requirements.

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