EPR thermal shrinkage cable terminal internal defect detection system and detection method thereof

Abstract

The invention discloses an EPR thermal shrinkage cable terminal internal defect detection system and a detection method thereof, belongs to the technical field of high voltage and insulation, and aimsto solve the problems of poor generalization performance, poor penetrability, great environmental temperature influence, damage to a detected object and the like. The system comprises a femtosecond laser, a spectroscope, a detection light path system, an excitation light path system, a lock-in amplifier and an acquisition terminal, wherein the femtosecond laser and the spectroscope are arranged from left to right along a terahertz pulse path, the detection light path system and the excitation light path system are arranged behind the spectroscope in parallel, and the lock-in amplifier and theacquisition terminal are connected with each other. The method comprises the steps of: sample preparation and installation, defect detection, data collection and processing and result application. The combination of the system and the method is the widening of the application of the terahertz nondestructive visual detection technology to an EPR thermal shrinkage cable terminal; the unique structure and the method are combined, the terahertz time-domain spectral characteristics of the internal defects of the EPR thermal shrinkage cable terminal can be clearly established; and finally, the reverse application is carried out, so that the nondestructive visual detection of the internal defects of a composite cable is realized.

Description

technical field [0001] The invention belongs to the technical field of high voltage and insulation, and in particular relates to an internal defect detection system and a detection method of an EPR heat-shrinkable cable terminal. Background technique [0002] EPR heat-shrinkable cable terminals have been widely used in medium and low voltage power systems and traction power supply systems due to their small size, light weight, easy installation, and wide application range. However, during the installation process, it is easily affected by factors such as the installation process, operating conditions, and external force damage; in the later use and long-term operation, its application scenarios are even more diverse, and it is often in harsh application conditions. . Therefore, in the long-term operation, due to the joint action of rapid cold and heat alternation, transient overvoltage shock and long-term high-frequency vibration, the internal insulation layers are separate...

AI Technical Summary

Problems solved by technology

However, during the installation process, it is easily affected by factors such as the installation process, operating conditions, and external force damage; in the later use and long-term operation, its application scenarios are even more diverse, and it is often in harsh application conditions.

Therefore, in the long-term operation, due to the joint action of rapid cold and heat alternation, transient overvoltage shock and long-term high-frequency vibration, the internal insulation layers are separated, resulting in micro air gaps and partial discharges; as the air gap continues Increase and gradually form a discharge channel, and the internal insulating layer material will be decomposed due to discharge ablation; with the further growth and expansion of the air gap and the continuous accumulation of discharge ablation carbides, the degree of discharge will continue to intensify, the air gap will continue to grow, and eventually form a through hole. line discharge channel, resulting in discharge breakdown

[0003] At present, the detection methods of EPR heat-shrinkable cable terminals are limited to the dielectric loss tangent angle test, partial discharge detection, infrared temperature measurement, etc. used in maintenance at all levels. Defects cannot be detected, and it is difficult to meet the needs of reality

[0004] In the prior art, the non-destructive testing methods for internal defects of cable terminals mainly include: CT scanning and X-ray scanning technology based on high-energy rays, which have been applied in GIS switchgear, cable terminals, insulators and other equipment, but due to X-ray It has poor detection effect on delamination and cracks, and it will produce high-energy ionizing radiation, which is harmful to the human body, so it is difficult to promote

Other detection methods are also unable to apply to the detection of composite cable terminals due to their own defects

For example, the ultrasonic method has a large energy attenuation in composite materials with strong sound absorption, and it is difficult to penetrate thicker material structures; the infrared wave method is greatly affected by the ambient temperature; the laser speckle imaging method requires a high-energy laser light source, which will affect damage to the measured object

[0005] Based on the above problems in the background technology, there is an urgent need for a detection system and detection method for internal defects of EPR heat-shrinkable cable terminals to overcome poor generalization, poor penetration, large influence by ambient temperature, and damage to the measured object. And other issues

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