By hvhipot 
The fault of the zinc oxide arrester tester on site should be handled correctly
1. Zero adjustment of the meter head of the zinc oxide arrester tester
After using the zinc oxide arrester tester for a period of time, it may need to be adjusted. Take the instrument movement out of the box, start the instrument, and the alarm light is on (Do not connect the test product at this time), press and hold the detection button and adjust the corresponding potentiometer on the circuit board (see the schematic diagram of the main components of the circuit board) , Until the meter head indicates “zero ± 1 word” respectively for voltage and current zero adjustment.
2.0.75U1mA calibration
The zinc oxide arrester tester sets the calibration button to 0.75U1mA state, connects the test product, presses the test button, reads the voltage value of U1mA, and releases the test button. At this time, the voltage of the instrument will immediately change to another voltage value U1. 0.75U1mA, compare the two, if U1=0.75U1mA, no adjustment is needed; U1≠0.75U1mA, then make appropriate adjustments and adjust the corresponding potentiometer on the circuit board until U1=0.75U1mA. After the instrument is calibrated, the measurement accuracy can be guaranteed for a long time without frequent adjustments. After calibration, set the calibration button to U1mA state.
3. Instrument error adjustment
After using the zinc oxide arrester tester for a period of time, if there is an error in the zinc oxide arrester tester, you can adjust it. After connecting the test product, if the U1mA value is determined, assuming it is 27.0kV, press and hold the test button and see Whether the indicated value of the voltmeter is equal to the reference voltage U1mA (27.0kV) of the tester, if the zinc oxide arrester tester is not equal, adjust the quasi-potentiometer on the left side of the voltmeter head. After the adjustment is completed, release the detection button. (See figure 1 below, adjustment of reference voltage)
4. Handling of simple faults of zinc oxide arrester tester
If the head of the ammeter displays “[[[” or is not adjusted to zero, it means that the input protection level op amp (CA3140E) IC1 (equivalent to the fuse) of the current loop is damaged. Replace the configured components.
Test test of zinc oxide arrester tester:
1. Thermal breakdown of zinc oxide arrester
The final cause of the thermal breakdown of the zinc oxide arrester generator is that its heating power is greater than its heat dissipation power. The heating power of the zinc oxide valve plate depends on the current and voltage on it (current is the active component of the current flowing through the valve plate).
2. Moisture inside the zinc oxide arrester
If the seal is not tight, it will cause moisture inside the arrester or moisture ingress during installation, which will increase the total current of the arrester under voltage. When damp to a certain degree, discharge will occur along the surface of the zinc oxide valve disc or the inner wall of the porcelain sleeve, causing the arrester to explode. The increase in the total current caused by the damp of the zinc oxide lightning arrester is caused by the increase in the resistive leakage current. It can be inferred whether it is damp or not by detecting the change of the viewing angle. Therefore, after each test, it should be stored in a ventilated and dry place to avoid moisture again.