Ultrasonic testing method and ultrasonic testing system for internal defects of GIS epoxy insulator

Abstract

The invention belongs to the technical field of power transmission and transformation insulation equipment, and relates to an ultrasonic testing method and an ultrasonic testing system for internal defects of a GIS epoxy insulator. The ultrasonic testing method for internal defects of the GIS epoxy insulator comprises the following steps: constructing the ultrasonic testing system for internal defects of the GIS epoxy insulator; testing a testing standard component based on the ultrasonic testing system, and obtaining a non-defective reflected wave waveform of the standard component; testing the GIS epoxy insulator based on the ultrasonic testing system, judging interior bubbles and cracks of the epoxy insulator by using a defect judgment method, and then continuously testing the GIS epoxy insulator along the moving path of a probe. The method is high in testing precision and efficiency and accurate in defect positioning, small-sized bubbles and cracks can be tested, and the method can be used for pre-delivery inspection of insulators and also can be used for assembling field test of insulators. The ultrasonic testing system for internal defects of the GIS epoxy insulator comprises an ultrasonic instrument, an oscilloscope, an ultrasonic longitudinal wave normal probe, a computer and the GIS epoxy insulator. The system is low in cost, small in equipment volume, high in testing precision and efficiency and accurate in defect positioning.

Description

Technical field [0001] The invention belongs to the technical field of power transmission and transformation insulation equipment, and relates to an ultrasonic detection method and system for internal defects of GIS epoxy insulation. Background technique [0002] Basin-type insulators are an important part of gas-insulated combined electrical appliances (GIS). They are mainly used for electrical insulation, isolation of adjacent gas chambers, and support for conductors. As one of the weakest links, the performance of the insulator determines the normal operation of the GIS. The internal defects of basin insulators mainly include bubbles and cracks: the bubbles are formed by the incomplete removal of air or the presence of impurity gases when the epoxy resin and the filler are mixed during the production and processing; the temperature changes during the curing during the production process, and the force is not received during the transportation and installation process. Balance,...

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Problems solved by technology

[0003] At present, the internal defect detection methods of basin insulators for GIS are divided into two categories: factory inspection generally adopts X-ray imaging technology, which has the advantage of being able to detect large bubbles inside basin insulators and high detection efficiency, and its disadvantage is that the width is small The sensitivity of crack detection is not high, and the equipment is large and expensive, and the radiation has potential harm to the human body, so it cannot detect insulators in the assembly site process; the detection methods based on electromagnetic waves, sound waves, and currents generated by partial discharge of defects have unique characteristics. High-frequency method, partial discharge ultrasonic detection, pulse current method, etc.

The ultra-high frequency method is mostly used for on-site monitoring, and the detection sensitivity can reach 5pC, but the defect location is not accurate enough, so it cannot be quantitatively detected; partial discharge ultrasonic detection is often used for live inspection, the defect location is accurate, and the discharge amount of 10pC can be detected, but the detection efficiency is low , and is not sensitive to discharges such as air bubbles inside pot insulators; the pulse current method can quantitatively detect discharges, and can detect 2pC discharges. Because it is easily affected by interference signals, it is mostly used in laboratory testing at present.

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