Causes and Measures for Flashover Discharge of Transformer Bushing

Flashover discharge of bushings can cause heating and aging, leading to short circuit accidents at transformer outlets, with low-voltage bushings being particularly vulnerable. The main causes and measures are as follows

Surface Contamination

• Cause: Dirt increases conductivity, especially in rainy and humid weather.
• Measure: Power off the transformer to clean the bushing and apply RTV long-lasting paint to enhance its anti-pollution flashover performance.

Installation, Maintenance, or Manufacturing Defects

• Cause: Insulation indicators such as dielectric loss angle exceed standards or porcelain parts are incomplete.
• Measure: Replace the defective bushing.

Inadequate Creepage Distance

• Cause: Small external creepage distance in design, particularly problematic in high-dirt areas.
• Measure: Replace with a bushing that has a larger creepage distance or silicone rubber outer insulation, or implement anti-pollution measures such as adding silicone rubber to the creepage skirt.

Internal and Atmospheric Overvoltage

• Cause: Overvoltage conditions within the system.
• Measure: Test and inspect the bushing and transformer, ensuring all components meet standards before operation.

Debris on Bushing Surface

• Cause: Debris can short-circuit parts of the porcelain skirt.
• Measure: Remove debris with an insulating rod while the transformer is live.

Weather Conditions (Rain, Snow, Ice)

• Cause: Ice formation on the transformer bushing during inclement weather.
• Measure: Cease operation until conditions improve.

By addressing these causes and implementing the corresponding measures, the risk of flashover discharge and subsequent damage can be mitigated effectively.