NOYAFA Electronic specializing in testing instruments and cable testers for 16 years
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NOYAFA Electronic specializing in testing instruments and cable testers for 16 years
Author: Noyafa–POE Tester
What points should be paid attention to in the buried cable fault instrument? What points should be paid attention to in the buried cable fault instrument? Buried cable power supply is more and more widely used due to its advantages of safety and reliability, beautifying the city, and the layout of factories and mines. But underground cables are usually buried in the ground. Once a fault occurs, it is necessary to adopt the appropriate buried cable fault test method to find the fault point as accurately as possible, and quickly carry out the buried cable fault repair to reduce the loss caused by the power outage.
After the underground cable fault occurs, the nature of the fault is preliminarily determined by measuring insulation resistance and other methods; then, according to the type of underground cable fault, an appropriate distance measurement method is used to initially measure the fault distance; The fixed point until the accurate fault location is found, so as to realize the fault repair of the underground cable. There are many reasons for the failure of buried cables due to the failure types of buried cables, such as mechanical damage, insulation damp, insulation aging and deterioration, overvoltage, material defects in Wuxi cable fault repair, cable insulation logistics loss, poor design and manufacturing process, sheath corrosion Wait. According to the location of the buried cable fault, the fault types can generally be divided into disconnection faults, main insulation faults and sheath faults.
The disconnection is generally caused by the excessive fault current of the buried cable, the burning of the cable core or the external mechanical damage, and the test is relatively simple. Generally speaking, the main insulation fault can be equivalent to a circuit, in which the size of the resistance mainly depends on the carbonization degree of the cable medium, the breakdown voltage of the gap G depends on the distance of the discharge channel, and the capacitance CF depends on the humidity at the fault point and its vicinity Degree (its value is small and can generally be ignored). Main insulation faults are generally classified into low resistance, high resistance and flashover faults based on fault resistance and breakdown gap.
In general, the boundary between low-resistance faults and high-resistance faults is 10 times the wave impedance of the cable itself, but it is not necessary to strictly distinguish in actual test work. Flashover faults have high resistance at the fault point, which can apply high voltages to the faulty cable, and the fault point will flash over and fail. This is the case for most failures in preventive testing.
What points should be paid attention to in the buried cable fault instrument? Fault types of buried cables Shenzhen Noyafa Electronic Technology Co., Ltd.
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