GIS type current transformer test method

Abstract

The invention provides a GIS type current transformer test method. The CT hysteresis loop measurement function and the CT and PT alternating current and direct current resistance measurement function are added and the problem that an extrapolated result acquired through a traditional low-voltage extrapolation method is not accurate is solved. The traditional highest test voltage of the transformer is increased to 45 kV from 400 V, CT volt-ampere characteristic test accuracy is increased to 0.001 V (0.001 A) from 0.1 V (0.1 A), the inflection point test function is added, and the transformation ratio test range is increased to 1:35,000 from 1:2,000. By the adoption of the method, the turn ratio of a current transformer is accurately measured through the high-frequency voltage, line-frequency induction voltage interference is avoided, and exciting currents generated in the turn ratio measurement process are reduced. A test method is implanted in a GIS type current transformer test device through software, and the GIS type current transformer is measured. The method is suitable for various current transformers including the GIS type current transformer and field verification of metering current transformers in a 10 kV to 500 kV transformer substation.

Description

Technical field [0001] The invention relates to a GIS type current transformer testing method, which belongs to the technical field of electric power measurement. Background technique [0002] The current testing methods of current transformers include traditional up-current comparison method, load extrapolation method and low-voltage extrapolation method. These three methods provide technical means for the verification of current transformers, but in the actual field inspection process of current transformers, these three methods have deficiencies and problems to be solved. These problems are as follows: [0003] Traditional up-current comparison method: long test leads, large power supply capacity required, multiple equipment, troublesome operation, and current-boost devices and voltage regulators interfere with the test process. [0004] When testing the transformer, a large current source is used to inject the tested transformer and the standard transformer at the same time, and...

AI Technical Summary

Problems solved by technology

[0015] In short, the traditional test method of current transformer has the following deficiencies: 1) It is susceptible to power frequency electromagnetic field interference; 2) It cannot measure the hysteresis loop of CT; 3) It cannot measure the AC and DC resistance of CT and PT; The maximum test voltage of the push method CT is <400V; 5) The accuracy of the CT volt-ampere characteristic is low, and the inflection point cannot be tested; 6) The transformation ratio range of the test is <1:2000

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