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What are the Cable Failure Point Detection Techniques?

Feb. 20, 2020

As a Rubber Cable Factory, share with you. During long-term use, power cables will inevitably fail due to various reasons. Affects the smooth production of the enterprise, so it is of great significance to be able to quickly troubleshoot and restore normal power supply.

1. Common faults and causes of power cables

Common faults of power cables include poor conduction, poor insulation, short circuits, and open circuit faults.

The cause of poor electrical conductivity is generally that the cable terminals are not tightly connected, resulting in increased contact resistance.

The causes of poor insulation and short-circuit faults are generally the cable's own insulation materials and manufacturing process defects; the cable head insulation materials, manufacturing process defects, and construction methods are not correct; the insulation is dampened, aged and deteriorated; and it is caused by long-term overvoltage.

Open circuit faults are generally caused by external mechanical damage.

Basically, cable failures are caused by poor insulation or damaged insulation. Usually, the fault can be solved as long as the damaged insulation is restored, so the detection and confirmation of the fault point of the cable is the key to solving the problem.

Rubber Cable (IEC)

Rubber Cable (IEC)

2. Commonly used Rubber Cable fault detection methods

At present, the detection of power cable fault points is usually measured by the bridge method, low-voltage pulse reflection method, pulse current method, two (multiple) pulse method, and acousto-magnetic method.

Bridge method

Short-circuit the faulty phase of the tested cable with the faulty phase. The two arms of the bridge borrow the faulty phase and the non-faulty phase, adjust the resistance to balance the bridge, and then use the formula to calculate the location of the fault point. Its characteristics are simple. Convenient and accurate.

Low voltage pulse reflection method

During the test, a low-voltage pulse is applied to the faulty phase of the cable. When the pulse propagates along the cable to the impedance mismatch point, the pulse reflection will be sent to the test point. According to the time difference between the transmitted and reflected pulses and the wave velocity of the pulse in the cable , You can calculate the location of the fault point.

Pulse current method

Use high-voltage pulses to click through the cable fault, collect and record the pulse current waveform after the fault click through the meter, find the distance between the primary and secondary reflected pulses of the fault point, and locate the cable fault point.

Two (multiple) pulse method

A low voltage pulse is transmitted to the faulty cable and the waveform is recorded. Then a high voltage pulse is transmitted to the faulty cable to click through the fault, and a low voltage pulse is transmitted again, and the low voltage pulse is reflected back at the breakdown point. The waveforms of the two low-voltage pulses are superimposed, and the intersection point is the location of the fault point.

Our company also has Rubber Cable (IEC) on sale, welcome to consult.

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