Have the field test of circuitry of high-pressured XLPE insulated cable with alt

Summary: Have the experience of field test with volts d.c. according to XLPE insulated cable, the requirement develops new method. Device of resonance of series connection of frequency modulation of a kind of movable type can use alternating voltage to have a test now, this means the experiment after applying to plastic insulation cable to lay to will have major breakthrough. Deserve to have by outdoors receive the jumper to cable road with indoor switchgear, in order to satisfy the requirement of different user.
Key word: Insulated cable of XLPE of alternating voltage high pressure experiments
Thousands of meters long cable line has large electric capacity, for example the polyethylene of 110 KV cross-linking with long 10 Km (XLPE) insulated cable, those who press its cut area is different, capacitance can amount to F of μ of 2 ～ 3. If be in systematic frequency (field test has with alternating voltage below 50 Hz) , need very big without result power. As above cable, undertake below 160 KV(2.5 U0) alternating voltage experiments, need possibly to be as high as the power of test of 20 MVA. Equipment of groovy alternating voltage test (the weight that the defect of running frequency 50 Hz) depends on its unit power of test is greater, amount to 100 ～ 200 N/kVA, the carriage of test equipment is very wasteful, and need provides quite big power source in the spot.
Well-known, the field test of cable of power of insulation of oily dip paper uses volts d.c. commonly. Leak electric current can be measured at the same time when the experiment, by the change of leak electric current or the relation of leak electric current and experiment voltage, usable in order to judge insulation situation. Tens of year the practice that uses dc compression test to cable of power of insulation of oily dip paper, already proved its serve as the spot fixed preventive test project can reach satisfactory test result, this fills oil and cable of calm sb's anger to have the reason of field test with volts d.c. namely. This experiment method is used at high-pressured XLPE insulated cable as much, it is exclusive and feasible method it seems that.
Circuitry of insulated cable of 1 　 XLPE uses the weakness that dc compression experiments
The running test of circuitry of high-pressured XLPE cable makes clear, the spot uses dc compression to experiment cannot effectively check gives defective XLPE insulated cable and accessory. The XLPE insulated cable that discovery of check of go by of each country carry experiments through dc compression and accessory have puncture breakdown to happen after investment moves.
For this, CIGRE WG21-09 working group (tall extrusion wraps insulated cable to experiment) mixed to manufacturer of cable of world each country 1984 power company investigation, organize sample of travel imitate structure to experiment, affirming high-pressured XLPE insulated cable uses dc compression to experiment further is impertinent, its put in the following and apparent weakness:
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