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Analysis Of Advantages/Disadvantages Of AC/DC In Cable Withstand Voltage Test

Time:2020-07-30 Number:3

       Cable withstand voltage test AC and DC two ways have advantages and disadvantages, now GDZX summarizes and analyzes the advantages and disadvantages of cable DC withstand voltage and AC withstand voltage, for your reference.
Cable Withstand Voltage Test.jpg

I DC withstand voltage test of cable

1. Advantages:

       If the cable adopts DC withstand voltage method to withstand voltage, the leakage current will be very small, and the power of DC high-voltage generator is relatively small, so the equipment is light and easy to carry;

2. Disadvantages:

       It is easy to generate parasitic charge when DC is used for cable withstand voltage, and the higher the voltage is, the greater the charge is, and the discharge can not solve the problem at all. It has been proved that many good cable partial insulation problems have occurred when using DC voltage withstand test for 35kV and above cables. At present, AC test is mandatory for 35kV and above cables. The DC voltage withstand test is destructive to the cable, and the cable should be charged and discharged during the DC test. The cable is running in the AC environment, so the DC voltage withstand test is not true. 

II AC withstand voltage test of cable

1. Disadvantages:

       If AC is used for cable withstand voltage test, the power requirement of the equipment is relatively increased, and the weight is significantly heavier than that of DC withstand voltage equipment. Although the AC voltage withstand equipment is modularized into five parts, it is still not convenient to carry DC equipment.

2. Advantages:

       In addition, AC equipment has many advantages, such as large screen color screen touch control, perfect man-machine interface, one button automatic control fool operation mode, which is much more convenient than DC. And the key is that the AC withstand voltage will produce a positive and negative 180 degree magnetic field. During the test, the cable does not carry any parasitic charges, which effectively protects the cable, and the cable is basically undamaged.

       In recent years, the test and operation experience at home and abroad have proved that DC withstand voltage test can not effectively detect the insulation defects in XLPE cables, and even cause insulation hidden dangers of cables. Cable accidents have occurred many times at home and abroad, and a considerable number of cable faults are caused by the negative effects of frequent DC voltage withstand tests. Therefore, the AC voltage withstand test should be selected, which is closer to the actual use.

       The frequency conversion series resonance test device developed and produced by Wuhan GDZX is suitable for AC voltage withstand test of 10kV, 35kV, 110kV cables, transformers below 500kV, GIS system, SF6 switch, CT / Pt, insulator, bus, cable, bushing and other capacitive equipment AC withstand voltage test, and is sold well at home and abroad.