High-precision sampling method of low-voltage circuit breaker

Abstract

The invention provides a high-precision sampling method for a low-voltage circuit breaker, and the method comprises the following steps: S1, carrying out the voltage reduction of a three-phase voltage signal inputted by the circuit breaker through a resistor voltage dividing mode, and transmitting the signal to a metering chip; s2, converting the three-phase current signal through a special metering transformer, and transmitting the converted three-phase current signal to a metering chip through a filter circuit; s3, the metering chip carries out internal calculation according to the collected three-phase voltage and current signals to obtain original data; according to the invention, high-precision power grid parameter measurement can be completed on the premise that the protection function is not affected.

Description

technical field [0001] The invention relates to the technical field of circuit breakers, in particular to a high-precision sampling method for low-voltage circuit breakers. Background technique [0002] In traditional low-voltage circuit breakers, the current sampling signal is generally obtained through ordinary current transformers, and then calculated. There are two problems in this type of method: First, this type of transformer has poor linearity and low accuracy. For protection, it can only meet the accuracy requirements of the protection function, and is far from the accuracy requirements of the measurement standards; second, the collected current and voltage signals need to be calculated by the MCU to obtain more measurement parameters such as power and electric energy, and It is necessary to add various complex processing such as phase compensation. Due to the many hardware and software influencing factors involved, even after the above-mentioned various processing,...

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Problems solved by technology

[0002] In traditional low-voltage circuit breakers, the current sampling signal is generally obtained through an ordinary current transformer, and then calculated. There are two problems in this type of method: First, this type of transformer has poor linearity and low precision. Usually, it is mainly used For protection, it can only meet the accuracy requirements of the protection function, and is far from meeting the accuracy requirements of the measurement standard; second, the collected current and voltage signals need to be complexly calculated by the MCU to obtain more measurement parameters such as power and electric energy, and Various complicated processing such as phase compensation should also be added. Due to the many hardware and software influencing factors involved, even after the above-mentioned various processing, it still cannot meet the accuracy requirements of the measurement standard, and can only meet the general-purpose power grid parameter measurement requirements.

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