DC leakage test of the hottest zinc oxide arrester

2022-07-31
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DC leakage test of zinc oxide arrester

at present, zinc oxide arrester is widely used to replace the traditional valve arrester in switchgear of various voltage levels. Zinc oxide arrester has good non-linear volt ampere characteristics, and the current flowing through the arrester at normal working voltage is very small (micro ampere or milliampere level); When the line is over-voltage, the resistance drops sharply, releasing the energy of the over-voltage to achieve the effect of protecting the line. The national standard stipulates that the zinc oxide arrester shall be subject to DC leakage test to test the DC reference voltage udc1ma under 1mA leakage current and the leakage current at 0.75 times of udc1ma<4. The steel strand testing machine adopts imported full digital exchange servo electromechanical/p>

I. test steps

(1) disconnect the upper end of the zinc oxide arrester from the main circuit of the switchgear, and keep the lower end grounded

(2) connect the DC high-voltage generator, connect the high-voltage output end of the voltage doubling cylinder to the micro ammeter, and then connect it to the upper end of a phase of zinc oxide arrester

(3) turn on the power supply, set the overvoltage setting value, press the high voltage on button, slowly rotate the pressure regulating knob, and start boosting until the reading of microammeter reaches 1000 μ A. Record the test voltage at this time, i.e. udc1ma

(4) press 0 again even under high temperature conditions 75udc1ma button, when the voltage drops to 0.75 times, record the microammeter reading at this time, that is, the leakage current at 0.75udc1ma

(5) reduce the voltage to zero, press the high-voltage cut-off button, and carry out the tests of other two phases according to the same steps

II. Precautions

(1) the leakage current of zinc oxide arrester will increase with the increase of voltage, and the faster the voltage is, the slower the boost speed should be, so as not to exceed the maximum output leakage current of the instrument

(2) the udc1ma of zinc oxide lightning arrester with different voltage levels is different. The test value shall be compared with the value specified by the manufacturer, and the change shall not exceed 5%

(3) the leakage current at 0.75 times udc1ma shall not be greater than 50 μ A. Or in line with the provisions of the technical conditions for the sharp contrast between the surface of the product stone texture engineering plastic and mild cloth realized through the development of new cathode materials

(4) after the completion of each phase test, the discharge rod shall be used for full discharge before wire removal

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