How to use high voltage power supply to detect high voltage cables
How to use high voltage power supply to detect high voltage cables
To ensure the normal and safe use of high-voltage cables, check the cable inlet before or after using them for a period of time. The test includes determining whether the main insulation is damp or aging, and checking whether there are defects in the main insulation of the cable after the voltage test. High voltage power supply is the main tool used for voltage resistance and insulation detection of cable.
The source of Radium specially produced a power supply type for the high voltage test of power supply :HY-12KV and HY-32KV. The input voltage of the power supply is 220V AC for daily civil use, and the output of the power supply is 12KV DC or 32KV DC. Such a high voltage output, but the power supply products can also achieve small volume, light weight, high efficiency, output voltage from 0V continuous adjustment to 12KV or 32KV and high stability. The power supply also has the function of open circuit protection, which can be open for a short time (it requires that the power supply housing is well dug, while avoiding arc pulling between the positive electrode and the housing).
Source of radium high voltage cable test power supply
Insulation detection:
In each measurement of the high voltage cable, the non-tested phase and the metal shield (metal sheath) and armored layer are grounded together. Use megohm meter, large capacity digital megohm meter is recommended. The "L" end leads and "E" end leads of megohm meters shall have reliable insulation.
The cable should be fully discharged before and after measurement for about 2-3 minutes. If a hand-operated megohm meter is used, do not stop shaking the handle before disconnecting the high voltage lead. The other end of the cable is not connected to the test equipment should be guarded, and no one is allowed to approach and contact. If the leakage current on the surface of the cable connector is large, shielding measures can be adopted. The shielding wire is connected to the "G" end of the megohm meter.
Test results:
Handover: before and after voltage test, insulation resistance has no obvious change.
Pre-test: greater than 1000 Mω
Pressure test:
Dc voltage test is suitable for paper insulated cable, rubber and plastic insulated power cable is suitable for AC voltage test. Our conventional cable is AC polyethylene insulated cable (rubber and plastic insulated power cable).
According to the test capacity (the formula S=wCUs2),0.1HZ AC voltage and 50HZ voltage compared, the former need power equivalent to 1/500 of the latter, so it can be no problem to produce portable equipment for field use. During the field debate team's voltage test of cable inlet line, the test voltage can be 1.5-1.8 times of 50HZ, which makes it easier to find cable insulation defects than DC voltage. For the cross Interlian system, DC voltage resistance test is carried out on each section of the cross interlian system. During the test, the cross interconnection connection of the cable metal shield is disconnected, the metal shield of the tested section is connected to the DC test voltage, and the cable metal shield of the non-tested section on the other side of the interconnection box is grounded. Test the outer sheath of insulation joint, insulation splint between interconnecting box sections, lead coaxial cable together with the outer sheath of cable.
