For electrical equipment, especially high-voltage electrical equipment, insulation performance tests shall be carried out after a period of time or operation. Detect its electrical insulation properties. In accordance with the provisions of the International "Procedures for Preventive Testing of Electrical Equipment":
1. The phase-separated insulation resistance of the fully connected phase-closed busbar with a rated voltage of 15kV and above is not less than 50MΩ at room temperature. The 6kV common box type enclosed busbar has a phase separation insulation resistance value of not less than 6MΩ at room temperature.
2. The influence of temperature on insulation temperature rises, and the insulation resistance of many insulating materials will decrease significantly. As the temperature rises, the atomic and molecular motion of the insulating material is intensified, the original molecular structure becomes loose, and the charged ions are generated by the electric field. Moving and transmitting electrons, the insulating ability of the insulating material is lowered. In response to this factor, the tester should convert the test results to the same temperature for vertical and horizontal comparison. If the test data differ greatly and does not meet the test procedures, the insulation should be analyzed for aging or moisture.
3.The effect of temperature on insulation (measuring insulation resistance can be used with HT2500 series high-voltage insulation resistance tester with temperature compensation function) When the insulation is in a humid environment, the surface will absorb moisture to form a water film, causing its surface to conduct electricity. Increase, so that the insulation resistance drops significantly. In addition, some insulating materials have a capillary action, which absorbs more moisture and increases the conductance, resulting in a decrease in overall insulation. In this case, equipotential shielding should be added.
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