Method and device for automatically calibrating micro-ammeters

Abstract

The invention provides a method and device for automatically calibrating micro-ammeters, which relate to the technical field of micro-ammeter calibration equipment. The method comprises the following steps that: firstly, through using a precision voltage source and a standard resistor, a voltage-current curve is obtained through measurement by using a precision ammeter; then, through using the precision voltage source, a voltage-current curve is obtained through measurement implemented by an ammeter to be calibrated; through data fitting, the parameters of the two curves are obtained; and through coefficient correction, the curve of the ammeter to be calibrated is close to that of a standard ammeter as far as possible. A hardware part of the device provided by the invention mainly comprises a computer, a precision voltage source, a standard resistor, a conversion module, a precision ammeter and an ammeter to be calibrated. By using the method and device provided by the invention, the test accuracy of a micro ammeter can be greatly improved, even close to that of a precision electrometer-level ammeter; the method is simple and reasonable, unique in principle and high in accuracy; the device is simple in structure and stable in performance; and the test accuracy requirements of the micro ammeter used in a depolarized relaxation current test for the insulation performance of high voltage equipment can be satisfied.

Description

technical field [0001] The invention relates to the technical field of micro-ammeter calibration equipment, in particular to a calibration method and device for a micro-ammeter used in an isothermal relaxation current method (IRC) test system for the insulation performance of high-voltage equipment. Background technique [0002] Current signal detection is an important means to evaluate the insulation state of insulating materials in high-voltage equipment. According to the nature of the measured current, the measured current signal can be divided into two categories: one is the polarization relaxation current of high-voltage equipment insulation under high-voltage electric field, The other is the depolarization relaxation current of high-voltage equipment insulation after the high-voltage electric field is removed. Isothermal relaxation current method (IRC) is a new type of non-destructive insulation state detection method based on current signal detection. Its basic princi...

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Problems solved by technology

[0003] The purpose of the present invention is to provide a micro-ammeter automatic calibration method and its device, which solves the problem of low test accuracy of the micro-ammeter used in the isothermal relaxation current method (IRC) test system for the insulation performance of high-voltage equipment. The device calibration can greatly improve the test accuracy of the micro ammeter, even close to the precision electrometer level ammeter; the method is simple and reasonable, the principle is unique, and the precision is high; the device structure is simple and the performance is stable; it can meet the requirements of high-voltage equipment insulation performance in the future. Test accuracy requirements of micro ammeter used in polarization relaxation current test

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