Three-phase four-wire electric energy meter zero line lack detection method based on voltage difference

Abstract

The invention discloses a three-phase four-wire electric energy meter zero line lack detection method based on voltage difference. The method comprises the following steps: respectively detecting three-phase voltage of a three-phase four-wire electric energy meter; detecting whether current exists in the zero line or not under the condition of detecting that voltage exists in at least two phases;calculating the voltage fluctuation ratio of the three-phase voltage under the condition that the current flows through the zero line; and judging whether the three-phase four-wire electric energy meter lacks a zero wire or not according to the calculated voltage fluctuation ratio. According to the three-phase four-wire electric energy meter zero line lack detection method based on the voltage difference, only internal programs of the electric energy meter are needed for implementation, no special hardware detection circuit is needed for cooperation, the zero line lack detection method can flexibly conduct judgment according to different preset zero line lack detection thresholds and detection time in the electric energy meter, only hardware cost is reduced, and the risk that a hardware detection circuit is inaccurate due to a complex on-site environment is greatly reduced.

Description

Technical field[0001]The present invention relates to a three-phase four-wire electrical energy table deficiency zero line detection method based on voltage difference.Background technique[0002]In the current power grown three-phase four-wire power supply system, if the three-phase load is normal, if the zero line is incorporated, the zero line is present, the zero line and the three-phase load constitute a balanced whole, the three-phase voltage remains stable. The measurement of each phase line voltage is not measured because of the disconnection of any pharmaceutical voltage. If the zero line does not enter the table, that is, the zero line is missing, when the three-phase load is unbalanced, the neutral point is offset, which causes any two-phase voltage in the triangular line voltage to be larger than the other phase voltage, and this change The relationship is not fixed, which causes a large fluctuation at the same time, thereby indirectly cause damage to the electric equipmen...

AI Technical Summary

Problems solved by technology

Due to the limitation of the normal operating voltage range of the hardware detection circuit itself, the risk of inaccurate measurement of the energy meter in the harsh and uncertain field environment is increased

Therefore, while detecting whether the neutral wire is entering the meter, considering the cost and the complex environment on site, the existing technology cannot guarantee the accuracy of the meter measurement

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