Working principle and operating precautions of the withstand voltage tester

The withstand voltage tester, also called electrical insulation strength tester, or dielectric strength tester, is also called dielectric breakdown device, insulation strength tester, high voltage tester, high voltage breakdown device, withstand voltage tester, etc. It is mainly used for withstand voltage test of polyethylene insulated power cables, and can also be used for insulation withstand voltage test of large power transformers. The withstand voltage tester uses ultra-low frequency high voltage to test the withstand voltage of power cables, which is a new method.

Its working principle is: a voltage higher than normal working voltage is applied to the insulator of the device under test for a specified period of time, and the voltage applied thereto will only produce a small leakage current, and the insulation is good. The test system consists of three modules: programmable power supply module, signal acquisition and conditioning module and computer control system. Two indicators for selecting the withstand voltage tester: the maximum output voltage value and the maximum alarm current value.

Features:

1. High-precision current and power measurement: The resolution of current and power measurement display is improved.

2. High-precision active power: The measurement has high-precision active power measurement, which can more effectively assist in the determination of inter-turn short circuits in some micro-electronic transformers.

Operation Notes:

1. The operator should put insulating rubber pads under his feet and wear insulating gloves to prevent high voltage electric shock from causing life-threatening danger.

2. The instrument must be reliably grounded. When connected to the object being measured, it must ensure that the high voltage output is "0" and in the "reset" state.

3. During the test, the ground terminal of the instrument must be reliably connected to the object being tested, and open circuit is strictly prohibited. Do not short-circuit the output ground wire with the AC power line to avoid high voltage on the shell, which may cause danger. Try to avoid short-circuiting the high-voltage output terminal with the ground wire to prevent accidents.

4. Once the test lamp or super leakage lamp is damaged, it must be replaced immediately to avoid misjudgment.

5. When troubleshooting, the power supply must be cut off. When the instrument is no-load and the high voltage is adjusted, the leakage current indicator has a starting current, which is normal and does not affect the test accuracy.

6. Avoid direct sunlight on the instrument and do not use or store it in a hot, humid, or dusty environment.