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
How does the power cable fault tester quickly and accurately locate the fault point of the cable? How does the power cable fault tester quickly and accurately locate the fault point of the cable? At present, there are three common faults in power cables, one is cable conductor fault (core wire and metal shielding layer), the other is cable main insulation fault, and the third is cable sheath fault (sheath fault). The main function of the power cable fault tester is to quickly identify the fault location of the cable so that the cable can be repaired and maintained. At the same time, there are many types of power cables with different structures and organizational forms.
In addition, there are different classification methods according to the needs of different departments. Wuhan Hezhong Electric briefly summarizes the following fault conditions. Categorize cable faults by fault location: 1.
Main insulation failure. The insulation between the cable conductor core and the ground or metal shield is damaged, resulting in various natural failures. Generally speaking, most faults in cables of 35kV and below fall into this category.
2. Sheath failed. Generally, it refers to the failure caused by damage to the metal sheath (layer) or insulating sheath of the cable.
What can be found in practice is the failure of the insulating sheath between the metal sheath and the earth. Most of these failures are leakage failures. Sheath faults are only related to single-core power cables with high voltage levels of 35kV and above.
3. Physical exhaustion. A complete transmission cable consists of two parts: the cable body and the cable joint. The fault of the cable must occur on the cable body and the cable joint.
The body of the cable can have failures of different nature, usually due to product quality and external damage. 4. Union failed.
To supply power with a cable, no matter the length of the cable, there must be two connectors at the beginning. For long-distance power supply cables or cable fault repair, the cable must also have a connector, that is, an intermediate connector. Generally speaking, a large part of cable faults are joint faults, and joint faults have different properties, but most of them are multi-phase, high-resistance earth leakage faults.
Power cable fault testers are classified according to cable fault and time to fault1. Operation failure. Operation failure refers to the failure of the protector to suddenly stop the power supply due to insulation breakdown or wire burning during the operation of the cable.
Such faults are usually single-phase or multi-phase, earth leakage faults. 2. Test failed.
Test failure refers to the failure of the power supply that can only be recovered after maintenance due to insulation breakdown or poor insulation in the preventive test. Classification according to cable fault and fault responsibility 1. Personnel fault improper cable selection, wrong three-terminal structure design, improper operation, poor maintenance, etc. Equipment defect.
Cable manufacturing defects, cable three-head accessories material defects, defects left over from old equipment, improper installation methods or poor construction techniques cause the three-head quality defects. 3. natural disaster.
Lightning strikes, floods, typhoon attacks, bird damage, insect damage, mudslides, land subsidence, earthquakes, natural disasters, etc. 4. normal aging.
Under normal circumstances, the insulation aging of the cable running for more than 30 years, the wet soaking of the outdoor head for more than 20 years, the high-end drying of the vertical oil-paper cable laying for more than 20 years, etc.5. External force damage, corrosion, user failure and trial of new products and new technologies. 1.
Short-circuit (earthed) type: One or more phase conductors of the cable have a penetrating fault to earth or the insulation between conductors. Depending on the short circuit (ground) resistance, there are high resistance, low resistance, and metal short circuit (ground) faults. 2.
Type of disconnection: The failure of one or more of the conductors of the cable is discontinuous. 3. Flashover type: The cable insulation breaks down instantaneously under a certain voltage, but the breakdown channel is randomly closed and the insulation recovers quickly.
4. Composite: A cable fault has more than two fault characteristics. How does the power cable fault tester quickly and accurately locate the fault point of the cable? Power cable fault tester manufacturer Shenzhen Noyafa Electronic Technology Co., Ltd.
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