How high a high-power high-voltage motor will produce a corona

Update:22 Jul 2021

Corona is a problem that is difficult to avoid with high-power and high-voltage motor products. Because at the stator winding end of the high-power high-voltage motor, the stator coil exit slot, the slot wall of the stator winding coil and the iron core, the three-phase winding out-of-phase coil end and other positions are prone to corona. In order to weaken the adverse effects of corona on high-power and high-voltage motors, inverter motor manufacturers will adopt certain methods in these parts.

In the above-mentioned parts, if the electric field intensity of the atmosphere is higher than the critical field strength, the atmosphere will be partially ionized and emit fluorescence, accompanied by the sound of "chichi" and "bimile". When the corona is just generated, the ionization and luminescence of the gas are only in the outer appearance, and the current is relatively weak. However, the ozone and nitrogen oxide generated by the gas ionization will corrode the winding insulation. Repeated and long-lasting corona phenomenon will cause The insulation performance of the windings is reduced, causing serious electrical disturbances.

But at what high voltage will corona occur? Is corona only related to voltage? This is a question that everyone is considerate. In fact, corona is related to the true state of the atmosphere, and it is easier to produce corona at higher altitudes.

The most common high-voltage motors have rated voltages of 6 kV and 10 kV. For 6 kV motors, the field strength of the stator winding slot is in a critical state for corona. Theoretically, motors used in non-plateau areas Generally, there will be no corona problem, as long as the motor used in the plateau area is treated with anti-corona treatment; and for motors with a rated voltage of 10 kV and above, it is necessary to organize anti-corona treatment.

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