1. Insulation resistance test
Insulation resistance is the most basic insulation index of electrical equipment and circuits. When a DC voltage is applied to the dielectric, after a certain period of time, the resistance corresponding to the leakage current flowing through the dielectric is called insulation resistance.
When the DC high voltage generator is used to pressurize the tested material, the current on the tested material will not reach a stable value instantly, but there is a attenuation process. At the same time of pressurization, a relatively large charging current flows through, followed by a relatively long slow decreasing absorption current, and finally a relatively stable conductive current is achieved. The higher the measured resistance, the longer it takes to reach equilibrium. Therefore, in order to correctly read the measured resistance value in the measurement process, it should be read after the value is stable.
2. DC withstand voltage and leakage test
For good insulation, the leakage current is very small under the action of DC voltage. With the increase of DC voltage, the passing current decreases at the same time. Under the condition of good insulation, with the increase of applied DC voltage, the leakage current increases due to the fast movement speed of ions. However, in the low voltage range, the leakage current has a linear relationship with the increase of applied voltage, and the increase range is very small.
3.DC withstand voltage test of rubber plastic cable
The voltage after the test is 3 times of the rated voltage of the cable. Under the specified test voltage (the test voltage shall be increased by 0.5 times of the rated voltage of each stage in sections, and the leakage current shall be recorded for 1min in each section; note: if the leakage current does not increase in proportion to the voltage, it must be analyzed and checked in time. Before withstand voltage, check the withstand voltage of DC high-voltage generator with high-voltage megger. The use method is the conventional connection method, one phase withstand voltage, one phase with withstand voltage device, the other phase is grounded, and the three-phase resistance is three times.
4.Zinc oxide arrester test
The DC high voltage generator is specially equipped with zinc oxide arrester test function. It can increase the voltage to 1mA leakage current, and then press the 0.75 times button. The instrument can automatically reduce the voltage to 0.75 times the voltage. At this time, the leakage current is 0.75 times U1mA leakage current of zinc oxide to be measured. This current can reflect the insulation state of zinc oxide arrester.
Kvtester Electronics Technology Co.,Ltd. is a R & D, production, operating in one of the high-tech enterprises, the company is mainly engaged in high voltage test equipment, power measurement and test equipment and instrumentation, substation online monitoring system and related software products R & D, design, production, sales and service. Its predecessor, Wuhan Institute of high pressure test equipment factory was established in 1992, is one of the earliest manufacturers engaged in high-pressure test.
ZC-540 DC high voltage generator is specially used to detect the electrical insulation strength and leakage current of power devices. The instrument adopts high-frequency voltage doubling circuit, applies new PWM pulse width modulation technology and voltage and current double closed-loop feedback technology, improves the power supply adjustment rate and load adjustment rate, and makes the voltage stability high and the ripple small.
