Conical capacitive transducer

Abstract

The invention relates to a conical capacitive transducer. The transducer comprises a first cone and a second cone which are coaxial, wherein a closed space is arranged in the first cone, the second cone is positioned in the closed space, and a dielectric membrane is filled between the inner surface of the first cone and the outer surface of the second cone; the bottom surface of the first cone is used as a high voltage electrode, and can form a high voltage arm capacitor with an external conductor and filling gas between the conductor and the bottom surface; the second cone is used as a low voltage electrode, and can form a low voltage arm capacitor with the conical lateral wall of the first cone and the dielectric membrane; and the conical top of the second cone is connected with a joint of a coaxial cable, and the other end of the coaxial cable is used as a signal output end. The low voltage arm capacitor formed in the conical capacitive transducer is larger than the low voltage arm capacitor of a flat capacitive transducer with the same induction area, so the conical capacitive transducer has large ratio; and the dimension in the voltage wave propagation direction gradually changes, so smooth transition of wave impedance is realized without forming reflection or refraction.

Description

technical field [0001] The invention relates to high voltage measurement technology, in particular to a tapered capacitance sensor. Background technique [0002] Gas Insulated Switchgear (GIS for short) / Half GIS (HGIS for short) has the advantages of small footprint, good sealing, little impact on the environment, high operational reliability, long maintenance cycle, and low maintenance workload. It has been widely used in my country's power grid, and has been successfully applied to UHV test demonstration projects. When the isolating switch, earthing switch and circuit breaker in GIS operate, they will generate high amplitude (up to 3p.u.), steepness (wave head time can be as low as several ns), high frequency (up to Up to 100MHz) very fast transient overvoltage (Very Fast Transient Overvoltage, referred to as VFTO). It poses a serious threat to the safe operation of the equipment. [0003] The rise time of VFTO is extremely short (only a few ns), and it is superimposed o...

AI Technical Summary

Problems solved by technology

[0005] At present, the VFTO measurement mainly adopts the plate capacitive sensor with the plate electrode structure, but the small voltage capacitance of this plate capacitive sensor leads to a small variable ratio, and its frequency band response range is narrow, which will make the RC time constant in the measurement circuit smaller, thus making the low frequency The response becomes worse and the frequency band narrows; in addition, it is difficult to match the impedance of the plate electrode structure with the impedance of the measurement cable, which will cause catadioptric reflection, and the catadioptric waveform will be superimposed on the measured voltage waveform, causing waveform oscillation and distortion

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