What are the detection methods for cable faults? Fault reason:
1. The insulation resistance has decreased. The breakdown of the cable core or insulation dampness reduces the insulation resistance value of the cable 2. The DC withstand voltage test voltage is low and cannot meet the rated requirements 3. During the AC withstand voltage test, excessive leakage current, waveform distortion, etc. caused disqualification 4. When testing in the case of a short circuit, the measurement results are too low due to the inductance effect 5. If the ambient temperature is too high, the temperature of the cable will increase and aging phenomenon will occur 6. Cables laid indoors or in pipelines are subjected to long-term exposure to sunlight or other heat sources, resulting in degraded performance Test items and methods:
1 DC resistance method (dg): A simple method of using a 500V megohmmeter to measure the magnitude and variation of the DC resistance value of the tested wire to ground to determine whether there is leakage. (Applicable to low-voltage power cables) 2. Leakage current method (dlt): Connect one end of the wire to be tested to the ground wire and the other end to the ground wire, and then connect it to a pointer instrument. Gradually increase the voltage to the specified value, and then read the value indicated by the pointer to obtain the leakage current value. (Applicable to high-voltage power cables)
3. Voltage withstand test method: An experimental method that tests whether the electrical insulation performance of the test object meets the requirements by grounding both ends of the test object and connecting it to a high resistance gear or voltage regulator to pressurize it to the specified voltage level for the specified time. (Suitable for cross-linked polyethylene and polyvinyl chloride power cables) 4. Temperature cycling inspection method: Place the test object in an environmental condition with a temperature of 70 ° C ± 5 ° C for a certain period of time before taking it out to determine whether it has aged or deteriorated based on the presence of condensation. (Suitable for cross-linked polyethylene power cables) 5. External inspection method and internal inspection method (1) External inspection method uses visual observation to discover the existence, type, and severity of defects. (2) Internal inspection method uses instruments and meters to determine the presence and degree of defects in the tested object through a certain program
Function of testing report:
1. Project bidding: Issue authoritative third-party CMA/CNAS qualification report
2. Online e-commerce platform entry: Quality inspection report recognized by major e-commerce platforms 3. Used as a sales report: issuing legally effective testing reports to make consumers more confident 4. Papers and research: Provide professional personalized testing needs 5. Judicial services: providing scientific, fair, and accurate testing data 6. Industrial problem diagnosis: Verify the troubleshooting and correction of industrial production problemsBaijian and testing process:
1. Telephone communication and confirmation of requirements
2. Recommend solutions and confirm quotations 3. Mail samples and arrange testing 4. Progress tracking and result feedback 5. Provide reports and after-sales service 6. If urgent or priority processing is requiredTesting and testing characteristics:
1. The testing industry is fully covered, meeting different testing needs
2. Fully cover the laboratory and allocate localized testing nearby3. Engineers provide one-on-one services to make testing more accurate
4. Free initial testing, with no testing fees charged
5. Self service order delivery for free on-site sampling
6. Short cycle, low cost, and attentive service 7. Possess authoritative qualifications such as CMA, CNAS, CAL, etc 8. The testing report is authoritative and effective, and is generally used in China