Insulation resistance test of high voltage distribution equipment
A, the insulation resistance of the movable part, measured with a 2500V shaking table, is not lower than 1mω.
B, the insulation resistance of high voltage main circuit, not less than 250 mω.
Low voltage: The insulation resistance test standard of 0.4KV low-voltage electrical equipment is that the insulation value of phase line to ground is ≥ 0.5 MΩ.
High voltage: The insulation resistance test standard of high voltage equipment above 6KV is to judge the insulation value of the equipment according to the equipment voltage motor. That is, the voltage level of 1KV is the insulation value of 1mω, so the insulation resistance of 6KV equipment is equal to or higher than ≥6mω, and that of 10KV equipment is equal to or higher than1mω.
Influencing factors:
The insulation resistance of general materials decreases with the increase of ambient temperature and humidity. Relatively speaking, surface resistance (rate) is more sensitive to environmental humidity, while bulk resistance (rate) is more sensitive to temperature. With the increase of humidity, the surface leakage increases, and the conductor conduction current also increases. With the increase of temperature, the movement speed of carriers will be accelerated, and the absorption current and conductance current of dielectric materials will also increase accordingly. According to relevant data, the resistance of dielectric at 70℃ is only 10% of that at 20℃. Therefore, when measuring insulation resistance, it is necessary to indicate the temperature and humidity when the sample is in equilibrium with the environment.
Refer to the above content: Baidu Encyclopedia-Insulation Resistance