Frequency conversion ground impedometer

Abstract

The present invention discloses a frequency conversion ground impedometer. The frequency conversion ground impedometer comprises: a micro-control unit (MCU), a digital-analog (DA) unit, a power amplification unit, an isolation transformer, an output shift switching unit, a current transformer, a first operational amplification and rang switch unit, a first filtering unit, a first module AD sampling unit, a second operational amplification and rang switch unit, a second filtering unit and a second module sampling unit. The frequency conversion ground impedometer belongs to the field of the electrical measurement, and especially has a broad application prospect and economic values in the field of the impedance ground parameters in a strong-interference environment such as a power transmission pole, a building and the like.

Description

Technical field [0001] The invention relates to the technical field of electric power measurement, in particular to a frequency conversion ground impedance measuring instrument. Background technique [0002] Ground impedance (usually called "ground resistance", which is actually an impedance value with inductive components) is the most important parameter reflecting the performance and state of the grounding grid. The importance of accurate measurement is self-evident. [0003] DL / T475-2006 "Guidelines for the Measurement of Characteristic Parameters of Grounding Devices" defines the grounding impedance as the impedance of the grounding device to the remote potential zero point. The value is the ratio of the potential difference between the grounding device and the remote potential zero point and the current flowing into the ground through the grounding device. [0004] Due to the strong 50Hz interference in the grounding grids of power transmission towers and buildings, weak test s...

AI Technical Summary

Problems solved by technology

The disadvantage is that because the measurement signal is a high frequency and small current, the reliability of the measurement data is low, and for the test circuit with certain inductance, the equivalence is poor

[0008] (4) Different frequency and high current method: The different frequency and high current large-scale ground network measurement system can output 10A level 45-55Hz different frequency sine wave current, which can improve the signal-to-noise ratio, improve the anti-interference ability, high measurement accuracy, and the results are real. However, its technology is complex, its volume and weight are large, it needs an AC power supply, and it is inconvenient to use in the field

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