The causes and treatment methods of partial discharge in switch cabinets. Partial discharge in switch cabinets means that once the electric field strength of the area reaches its breakdown field strength in the switch cabinet, the area will be discharged, but the two conductors of the applied voltage It does not run through the entire discharge process, that is, the discharge does not break down the insulation system. This phenomenon is called partial discharge. Partial discharge will promote the deterioration of the insulation of the switch cabinet and accelerate the aging of the switch cabinet. Therefore, it is very important to understand the principle and treatment method of partial discharge in the switch cabinet.

The cause of partial discharge in the switchgear is that the high-voltage terminals of high-voltage electrical equipment are exposed to the air, so the probability of corona discharge is relatively high. Corona discharge embodies the characteristics of a typical, extremely uneven electric field, and is also a unique self-sustained discharge under extremely uneven electric field. It is also possible that once the electric field strength inside the medium is lower than the electric field strength of the electrode edge air gap, and the dielectric creepage voltage is relatively low, creeping discharge will occur on the surface of the insulating medium. Generally, the voltage waveform, the distribution of the electric field, the air quality, the surface state of the medium, and the climatic conditions will affect the creeping discharge voltage, so the creeping discharge exhibits the characteristics of instability.

At the same time, it is inevitable that there are material and process defects in the production and processing of insulating media, which lead to internal defects in the insulating media, such as incorporation of a small amount of air or impurities. Once the insulation is subjected to high voltage, the internal defects may have local breakdown or repetitive breakdown. Generally, the characteristics of the medium itself, the size of the air gap, the location and shape of the defect, and the type of air gap gas will affect the conditions for the occurrence of internal discharge.

If you want to know whether there is a partial discharge in the switchgear, you can check it. When a partial discharge occurs in the insulation layer of the high-voltage switchgear, electromagnetic waves will be generated, and the metal shell of the switchgear will shield this electromagnetic wave. Part, but there is still a small part that will propagate through the seam of the metal shell or the gas-insulated switch gasket, and it will also generate a ground electric wave that is transmitted to the ground through the outer surface of the metal shell of the device. The range of the earth wave is usually from a few millivolts to a few volts, and the rise time is a few nanoseconds. The probe can be set on the outer surface of the switch cabinet in the working state to detect partial discharge activity.

The switchgear plays an important role in the use of the power system, and the partial discharge of the switchgear will have a huge impact on its service life. Therefore, the switchgear should be tested in time to find out the problem as soon as possible, and solve it as soon as possible to improve the switch. The service life of the cabinet.