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Three applications of DC high voltage generator

time:2020/10/27   source:华天电力  reading:446 time

The DC high voltage generator adopts large voltage feedback, which greatly improves the voltage stability, realizes high-quality, portable, and can withstand rated voltage discharge without damage. It is widely used in power cable detection tests and lightning arrester leakage current tests.

(1) Measure insulation resistance

The other two-phase conductors, metal shield or metal sheath and armor layer at both ends of the cable should be connected to each phase separately. For this test, it should be noted that the cable is a capacitive device, and the capacitive device should be aware of insulation resistance and absorption ratio. For example, fully discharge before and after the test, ignite first and then overlap, disconnect and then power off the vibration table.

(2) DC withstand voltage and leakage test

DC Hipot Tester.png

Oil-paper insulated cables are only used for DC withstand voltage, not AC withstand voltage. Thermal breakdown may occur due to the increase of AC. In the hot state, the electric field is unevenly distributed and the cable is easily damaged. It should be noted that the cable core wire is connected to the negative polarity: when the cable is wet, the water is positively charged. If the core is connected to the negative electrode, water will be concentrated in the core wire, and the moisture in the insulation will increase, which increases the leakage current and makes it easy to find defects. If the iron core is positive polarity, water penetrates into the lead package, the insulating water decreases, and the leakage current decreases. Small, the DC high voltage generator is not easy to find defects.

(3) Rubber-plastic cable test

Rubber-plastic cables refer to polyvinyl chloride, cross-linked polyethylene, ethylene-acrylic rubber insulated cables. Its characteristics are large capacity, high voltage level, light structure and easy bending. At present, oil-paper insulated cables have been gradually replaced. The difference between cross-linked polyethylene cables and familiar oil-containing paper-covered cables is that the main insulation between phases is cross-linked polyethylene plastic and double-layer semiconducting glue coating, and the outer surface of the core wire is coated with semiconducting glue. Overcome the corona and free discharge, so that there is a good transition between the core wire and the insulating layer. On the outer surface of the insulation between the core wire and the insulating layer, a second layer of semiconducting glue is coated in the copper tape shielding layer. The copper tape shielding layer is only a thin copper tape with a thickness of 0 mm and a thickness of 1 mm, forming an alternate shield Floor.

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