Resistance-capacitance voltage-divided zero-sequence voltage sensor

Abstract

The invention discloses a resistance-capacitance voltage-divided zero-sequence voltage sensor, comprising an A-phase resistance-capacitance voltage divider, a B-phase resistance-capacitance voltage divider, a C-phase resistance-capacitance voltage divider, and a secondary adjustment protection unit, wherein the A-phase resistance-capacitance voltage divider consists of an A-phase high-voltage armimpeder and an A-phase low-voltage arm impeder connected in series, the B-phase resistance-capacitance voltage divider consists of a B-phase high-voltage arm impeder and a B-phase low-voltage arm impeder connected in series, the C-phase resistance-capacitance voltage divider consists of an A-phase high-voltage arm impeder and a C-phase low-voltage arm impeder connected in series, the secondary adjustment protection unit consists of an adjustment resistor, an adjustment capacitor, a discharge tube and a varistor connected in parallel, each phase of low-voltage arm impeder and the secondary adjustment protection unit are connected in parallel to form a low-voltage voltage-dividing impeder, and the low-voltage voltage-dividing impeder outputs zero-sequence voltage values at two ends. The resistance-capacitance voltage-divided zero-sequence voltage sensor can output a voltage linearly proportional to a zero-sequence voltage, is used for monitoring the faults such as voltage imbalance of athree-phase power supply line, single-phase metal grounding, and phase losses, and has a great promotion and application value.

Description

technical field [0001] The invention belongs to the technical field of transformers, in particular to a voltage transformer, which is a resistance-capacitance voltage-dividing zero-sequence voltage sensor for measuring zero-sequence voltage. Background technique [0002] The zero-sequence voltage sensor is mainly used to monitor the unbalance of the three-phase power supply voltage of the power grid and the fault of single-phase metal grounding and phase loss. The existing technology uses three star-connected single-phase electromagnetic voltage transformers, and the neutral point of the star connection is grounded through the fourth single-phase voltage transformer to obtain zero-sequence voltage signals. This technical solution uses four A combination of single-phase voltage transformers, the product has many disadvantages such as high material consumption, large volume and weight, poor electrical performance of the overall product, and low partial discharge test pass rate...

AI Technical Summary

Problems solved by technology

Due to the different materials of high and low voltage capacitors in this solution, the temperature characteristic curves are inconsistent, and after the casting is completed, the capacitor and epoxy resin form a unified whole. The capacitor body produces mechanical force and changes the capacitance value, causing the error of the sensor to exceed the standard requirements in the operating temperature range of -40°C to +70°C

In addition, this solution does not consider the interference of the capacitor by the external electromagnetic field and stray capacitance, nor does it solve the problem of the discharge time constant

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