Characteristics of insulation withstand voltage tester

1. Four display windows simultaneously display high and low voltage, current and withstand voltage time, as well as multiple status indicators.

2. The test results can be viewed and printed, and have automatic / manual printing mode.

3. Man machine dialogue, full keyboard operation mode, the whole process of intelligent work, optional automatic mode and manual mode.

4. Real time display of high voltage, high voltage current, low voltage current, time and withstand voltage results, which is intuitive and clear.

5. Perfect overvoltage and overcurrent protection, arbitrarily set the output voltage, upper limit of high voltage current, upper limit of low voltage current and timing time.

6. It has the function of zero return detection. The test can be carried out only after the zero return is determined, which is safe and reliable.

8. The approximate voltage regulation algorithm will automatically withstand the voltage after reaching the set voltage, and automatically reduce the voltage and return to zero after the timing.

9. When the set high-voltage current or low-voltage current is exceeded, the voltage output will be automatically cut off, the voltage will be reduced to zero, and an audible and visual alarm will occur.

10. Software and hardware anti-interference design, a variety of anti-interference means to adapt to the harsh electromagnetic environment.

11. Automatic error diagnosis, easy to find and solve problems.

12. Wireless remote control function, remote communication, door interlock alarm light and alarm bell, external voltage divider calibration interface, etc.

Instrument detection principle

Compared with the main insulation of the transformer, that is, the insulation between windings and between windings and iron core, the transformer also has another important insulation performance index - longitudinal insulation. Longitudinal insulation refers to the insulation between different points and parts of transformer winding with different potentials, mainly including the insulation performance between turns, layers and sections of winding. The "induced voltage withstand test" specified in national standards and International Electrotechnical Commission (IEC) standards is one of the test methods specially used to test the longitudinal insulation performance of transformer.

The longitudinal insulation of transformer mainly depends on the insulating medium in the winding - insulating paint of enamelled wire itself, transformer oil, insulating paper, impregnating paint and insulating glue, etc. (different types of transformers may contain one or more insulating media); Longitudinal insulating dielectrics are difficult to ensure 100% purity, which will inevitably be mixed with solid impurities, bubbles or water, and will be damaged to varying degrees in the production process; The high field strength of the transformer during operation is concentrated at these defects. The temperature rise of long-term load operation reduces the breakdown voltage of the insulating medium, resulting in partial discharge. The power absorbed by the dielectric through the external alternating electric field, i.e. dielectric loss, will increase significantly, resulting in serious dielectric heating, increased dielectric conductivity, and high current at this part will also produce heat, The temperature of the dielectric will continue to rise, which in turn increases the conductivity of the dielectric. Such a long-term vicious cycle will lead to the thermal breakdown of the dielectric and the destruction of the whole transformer. This fault is manifested in the characteristics of the transformer, that is, the no-load current and no-load power consumption increase significantly, and the windings have adverse phenomena such as burning, arcing, vibration and howling. It can be seen that it is very necessary to detect whether the transformer contains longitudinal insulation defects by inductive withstand voltage test.