Author: Noyafa–Cable Tester Manufacturer
Cable Test Quality Control Cable Test Quality Control Key Cable Test Quality Control 1. Dielectric Strength Experiment: The dielectric strength of a wire and cable refers to the ability of the insulating structure and insulating material to accept the action of an electric field without breakdown damage. In order to check the quality of wire and cable products, To ensure the safe operation of the product, all insulation types of wires and cables are generally subject to insulation strength tests. Dielectric strength test can be divided into withstand voltage test and breakdown test. The withstand voltage test is to apply a certain voltage to the test sample under certain conditions, and after a certain period of time, the occurrence of breakdown is used as the criterion for judging whether the test sample is qualified.
The voltage at time is generally higher than the additional operating voltage of the test product. The specific voltage value and withstand voltage time are specified in the product specification. After the withstand voltage test, the reliability of the product running under the operating voltage can be detected and the serious shortcomings in the insulation can be found, and some shortcomings of the production process can also be found, such as: the insulation has serious external damage, and the conductor has serious shortcomings of sharply distorting the electric field ; Insulation has penetrating defects or large conductive impurities in production. The breakdown test is to measure the breakdown field strength or breakdown voltage under certain experimental conditions, increase the voltage until the breakdown of the sample occurs.
After the breakdown test, the safety margin between the ability of the cable to accept the voltage and the operating voltage can be assessed. One of the important parameters in cable planning at breakdown field strength. Cables generally accept AC voltage during operation, but DC voltage is also accepted in DC transmission systems and some special occasions. High-voltage cables may also be attacked by atmospheric voltage (lightning) and operating overvoltage.
Therefore, according to the different experimental voltage waveforms, it can be divided into three types of dielectric strength experiments: 1. AC (power frequency) voltage, 2. DC voltage, and 3 impulse voltage. 2. Partial discharge measurement: This is mainly aimed at extruded cables. Since the oil-filled cable basically does not generate partial power; even if the oil-paper cable has partial discharge, it is usually very weak, such as a few PCs, so these cables can be partially discharged in the factory test.
On the other hand, the extruded cable is the opposite. Not only is there a high possibility of partial discharge, but also the damage to plastic and rubber caused by partial discharge is more serious. With the improvement of the voltage level and the improvement of the working field strength, this problem becomes more serious. For high-voltage extruded cables, partial discharge measurements are required in the factory test. 3. Aging and stability test: The aging test is a stability test that can maintain stable function under the action of stress (mechanical, electrical, thermal). A simple thermal aging test is to detect the aging characteristics of the test sample under the action of heat: put the test sample in an environment with a temperature higher than a certain value of the additional operating temperature, and after a regular time, measure the aging of some sensitive functions before and after aging. changes to identify aging characteristics.
It is also possible to accelerate the aging of the test product by increasing the temperature, and add thermal, mechanical, electrical and other stresses such as moisture, oscillation, and electric field to form an aging cycle. After each aging cycle, certain selected sensitive functional parameters are determined. Until the function drops to the value of the recognized life. In this way, at a higher temperature, a shorter lifetime (the time when the sample is heated) is obtained.
Cable Test Quality Control Key Cable Test Quality Control Shenzhen Noyafa Electronic Technology Co., Ltd.
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