NOYAFA Electronic specializing in testing instruments and cable testers for 16 years
Language
NOYAFA Electronic specializing in testing instruments and cable testers for 16 years
Author: Noyafa–CCTV Tester
The insulation resistance classification of the cable fault point: 1. Open circuit (open circuit) fault: any fault where the cable insulation resistance is infinite or the insulation resistance value of the normal resistance is the same, but the voltage cannot be fed to the user end. (The fault has reflection during the low-voltage pulse test, and the insulation resistance of the fault point of the cable is classified: 1. Open circuit (open circuit) fault: any fault where the cable insulation resistance is infinite or the insulation resistance value of the normal resistance is the same, but the voltage cannot be fed to the user end. (The fault is reflected during the low-voltage pulse test, and the reflected wave is in the same phase as the transmitted wave) 2. Low-resistance (short-circuit) fault: any fault where the insulation resistance of the fault point of the cable is less than the characteristic impedance of the cable, and even zero DC resistance is called a fault. Low-resistance fault or short-circuit fault (fault has reflection during low-voltage pulse test, and the reflected wave is inverse to the transmitted wave) 3. Resistance fault: The fault where the DC resistance of the cable fault point is greater than the characteristic impedance of the cable is called a high-resistance fault ( The fault has no reflection during the low-voltage pulse test.) High-resistance faults can be divided into two types of faults: high-resistance leakage faults: during the high-voltage insulation test of the cable, the leakage current increases with the increase of the test voltage, and the test voltage increases to the rated value. value (sometimes far below the rated value), and the leakage current exceeds the allowable value.
High-resistance flashover fault: When the test voltage rises to a certain value, the leakage current suddenly increases, and the needle monitoring the leakage current flashover swings. When the voltage drops slightly, this phenomenon disappears, but the cable insulation still has a very high resistance value .
Copyright © 2022 SHENZHEN NOYAFA ELECTRONIC CO.,LIMITED - www.noyafa.net All Rights Reserved.