1. The influence of high-voltage connecting lines on ground leakage current

Due to the fact that the wires connected to the test product are usually exposed to the air (without shielding), the pressurized end of the test product is exposed to the outside, so the surrounding air may be released, and the leakage current of the product to the ground, especially in high-altitude and thin air areas, is more likely to occur, which can affect the accuracy of the measurement of ground leakage current. Measures such as increasing the diameter of the wire, reducing the tip or increasing corona shielding, shortening the wire, and increasing the distance from the ground can reduce the impact on the measurement results.

2. The influence of air humidity on surface leakage current

When the air humidity is high, the surface leakage current is much greater than the volume leakage current. The dirt on the surface of the tested product is prone to moisture absorption, increasing surface leakage current. Therefore, the surface must be wiped clean and shielded electrodes must be used.

3. Temperature

The impact of temperature on the results of HVDC tests is significant. Therefore, it is necessary to convert the measured current values into the same temperature for analysis and comparison.

It is best to conduct the test at a temperature of 30~30 ℃ for the tested product, as the leakage current varies greatly within this temperature range, but changes very little at low temperatures. For example, after the motor has just been turned off and tested in a hot state, several measurements at different temperatures can also be compared during the cooling process.

4. The influence of residual charges

Whether the residual charge in the insulation of the tested product is depleted will directly affect the magnitude of the leakage current. Therefore, the tested tourmaline will be completely discharged before testing.

5. Judgment of measurement results

Convert the measured leakage current value into a comparison of the same temperature and rainfall for comparison in previous experiments, as well as for comparison of the same equipment and among similar devices.

For important equipment such as main transformers, generators, etc., the relationship curve i=f (t) of current variation with time and the relationship curve I=f (U) of current variation with voltage can be analyzed.

The current "standard" for equipment with specified leakage current should be judged based on whether it meets the specified value. For equipment that is not explicitly specified in the standard, the same equipment can be compared with each other, compared with previous test results, and compared with similar equipment, and analyzed and judged based on their changes.