The insulation resistance testerunder UHV power can help many power workers conduct various power tests more conveniently.
The most basic insulation index of a circuit. Low voltage electrical equipment handover test, the insulation resistance of motors, distribution equipment, and distribution lines at room temperature shall not be less than 0.5M Ω (the insulation resistance of equipment and lines in operation shall not be less than 1M Ω/kV). The insulation resistance of low-voltage electrical appliances, their connecting cables, and secondary circuits should generally not be less than 1M Ω; In relatively humid environments, the insulation resistance should not be lower than 0.5M Ω; The insulation resistance of the secondary circuit small busbar shall not be less than 10M Ω. The insulation resistance of Class I handheld electric tools should not be lower than 2M Ω.
Insulation resistance: The resistance corresponding to the leakage current flowing through a dielectric after a certain polarization process is completed by applying a direct current voltage to the dielectric is called insulation resistance.
Insulation resistance testing standard
1. Insulation resistance testing of high-voltage distribution equipment
1.1 The insulation resistance of the moving parts shall be tested with a 2500V vibration meter and shall not be less than 1M Ω.
1.2 The insulation resistance of the high-voltage main circuit shall not be less than 250M Ω.
2. AC motor insulation test
2.1 If the rated voltage of the stator is above 1000V, measure it with a 2500V vibrator, and the stator resistance should not be less than 1M Ω and the rotor resistance should not be less than 0.5M Ω.
2.2 When the rated voltage of the stator is below 1000V, measure it with a 1000V vibrator, and the insulation value should not be less than 0.5M Ω.
2.3 The rated voltage of the stator is below 500V, measured with a 500V vibrator, and the insulation value is not less than 0.5M Ω.
3. Insulation resistance test after communication motor maintenance
3.1 After maintenance, measure the insulation resistance between the winding phases and between phases and ground of the motor. For motors below 500V, the repaired insulation resistance shall not be less than 1M Ω, and for motors above 500V, the repaired winding insulation resistance shall not be less than 5M Ω.
4. Cable insulation resistance test
4.1 The insulation resistance of newly installed cables shall not be less than 50M Ω;
4.2 During operation, the insulation resistance of high-voltage cables shall not be less than 2M Ω, and that of low-voltage cables shall not be less than 0.5M Ω.
4.3 When measuring the insulation resistance of cables, the power side and load side should be disconnected. After measurement, the cable is discharged in three phases to the ground.
