The testing of wires and cables has always been an important part of the national standard wires and cables. The higher the quality inspection department of a wire and cable company, the better the quality and reliability of the wires and cables produced by this company. The stricter the quality inspection department of the third party, the more conducive to the development of this industry.
The following are several important indicators of wires and cables, which are the most critical indicators for measuring wires and cables-Anhui Hongye Cable
1. Measurement of DC resistance of the wire:
的 The conductive cores of wires and cables mainly transmit electric energy or electric signals. The resistance of the wire is the main indicator of its electrical performance. The core resistance is greater than the DC voltage due to the skin effect and the proximity effect surface when the AC voltage is applied. The ones that can only be tested are whether the DC resistance or resistivity of the wire core exceeds the value specified in the standard. Through this inspection, certain defects in the production process can be found, such as wire breaks or some single wires. Meet the standards; the length of the product is incorrect, etc.
2, insulation resistance test:
Insulation resistance type is an important index reflecting the insulation characteristics of wire and cable products. It has a close relationship with the product's electrical strength, dielectric loss, and the gradual deterioration of the insulation material under working conditions. For communication cables, if the insulation resistance between wires is too low, it will increase the loop attenuation, crosstalk between the loops, and long-distance power leakage on the conductive core. Therefore, the insulation resistance should be higher than the specified value.
3. Measurement of capacitance and loss factor:
When an AC voltage is added to the cable, a current flows. When the amplitude and frequency of the voltage are constant, the magnitude of the capacitor current is proportional to the capacitance of the cable (Cx). For ultra-high-voltage cables, the current of this capacitor may reach a value comparable to the rated current, which becomes an important factor limiting the cable capacity and transmission distance. Therefore, the capacitance of the cable is also one of the main electrical performance parameters of the cable. Through the measurement of the capacitance and loss factor, various insulation degradation phenomena such as insulation moisture, insulation layer and shielding layer peeling can be found. Therefore, both capacitance and TANδ measurements are performed in cable manufacturing or cable operation.
4. Insulation strength test:
The insulation strength of wire and cable refers to the ability of the insulation structure and insulation material to withstand the electric field without breakdown. In order to check the quality of the wire and cable product and ensure that the product can operate safely, all insulation types of wire and cable are generally subjected to insulation strength tests. . The insulation strength test can be divided into a withstand voltage test and a breakdown test. The time voltage is generally higher than the rated working voltage of the test product. The specific voltage value and withstand voltage time are specified in the product standard. Through the withstand voltage test, the reliability of the product at the working voltage can be tested and the seriousness of the insulation can be found. Defects, can also find some shortcomings of the production process
5. Aging and stability test:
The aging test is a stability test that can maintain stable performance under the action of stress (mechanical, electrical, and thermal). Thermal aging test: A simple thermal aging test is to test the characteristics of aging of the test product under the action of heat. Put the test product in an environment with a certain value higher than the rated operating temperature, so that at a higher temperature T, Shorter life.
6. Thermal stability test:
The thermal stability test is that the cable is subjected to a certain voltage while being heated by the current. After a certain period of heating, certain sensitive performance parameters are measured to evaluate the stability of the insulation. The insulation stability test is divided into two types: long-term stability test or short-term accelerated aging test.