PVC Electric Cable

Generally speaking, power cables mainly include disconnection faults, grounding or short-circuit faults, disconnection and grounding faults, flashover faults, etc. We can determine the fault type of power cable according to some of the following methods. An insulation resistance meter is needed here. For wires and cables, place the insulation resistance meter at one end of the line to measure the insulation resistance of each phase.   1) When one or more cores of the shake measuring cable are discontinuous and are grounded through a resistor, it can be judged to be a disconnection and ground fault.   2) When the insulation resistance of one or several cores of a cable to the ground is measured remotely, or the insulation resistance between cores is much lower than the normal value, but higher than 100 kiloohms, it is a high resistance ground fault.   3) When the insulation resistance of one or more cores of the shaking cable to the ground is high or normal, a conductor continuity test should be conducted to check whether there is any disconnection. If so, it is a disconnection fault.   4) When the insulation resistance of one or several cores of a cable to the ground is measured remotely, or the insulation resistance between cores is less than 100 kiloohms, it is a low-resistance grounding or short-circuit fault.   5) Flashover faults often occur in preventive withstand voltage tests, and most of them occur at cable terminals and intermediate joints. Flashover sometimes occurs multiple times in a row, each time separated by seconds to minutes.   The instruments and equipment used in the past include QF1-A cable detector, DLG-1 flash detector, cable path meter and fault location meter, etc. The current popular test method is the flash test method, which includes flash and direct flash, and the flash test method is commonly used. The flash test has high accuracy, simple operation, safety and reliability. Its equipment mainly consists of two parts, namely high-voltage generating device and current pulse meter. The high-voltage generating device is used to generate DC high voltage or impact high voltage, which is applied to the faulty cable to force the fault point to discharge and generate a reflected signal. The current pulse meter is used to pick up reflected signals to measure fault distance or directly use low-voltage pulses to measure open circuits, short circuits or low resistance faults.