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PVC insulation sleeve

PVC insulation sleeve
PVC insulation sleeve

The dirty appearance of the PVC insulation sleeve will reduce the flashover voltage (that is, the low voltage of the flashover). If the dirty appearance is wet, the flashover voltage will drop even lower. At this time, if there is a certain value of overvoltage in the line Invasion, causing flashover. Flashover has the following hazards:

(1) Formation of a ground fault in the power grid, causing protection actions and tripping of the circuit breaker;

(2) Damage to the appearance of the bushing becomes an element that may cause insulation breakdown in the future.

After the dirt on the surface of the PVC sleeve absorbs moisture, the conductivity is improved, leakage current is added, and the insulating sleeve is heated. The corrugated tube may cause cracks in the sleeve and cause breakdown.

The occurrence of cracks in PVC insulation sleeves will reduce the electrical strength. Because the crack is filled with air, the dielectric constant of the air is small, the dielectric constant of the porcelain part of the porcelain sleeve is large, and the distribution law of the electric field strength is that the electric field strength with a small dielectric coefficient is large and the electric field strength with a large dielectric coefficient is large When the electric field strength in the crack is small enough, the air will be released, causing partial discharge, and further damage to the insulation, until the breakdown. When water enters the crack and freezes, it may also rupture the casing.