How to Select Suspension Glass Insulators for HV Transmission Lines

Suspension glass insulators are the workhorse of overhead high-voltage lines. Choosing the right disc type keeps your line reliable for decades. This guide walks through the key selection criteria.

1. Mechanical strength

Match the specified mechanical failing load to the span and load zone. Common ratings range from 70 kN (U70BP) for general lines up to 100 kN (U100BLP) and higher for heavy ice or long-span sections.

2. Voltage class & string length

The number of discs per string is set by the line voltage and required creepage distance. More discs mean higher flashover voltage — verify the string against your switching and lightning impulse levels.

3. Pollution performance

For coastal, industrial or desert areas, choose anti-fog bell-type sheds (U100BLP) that improve the creepage path and self-cleaning under rain.

• Confirm IEC 62217 type-test reports
• Specify hot-dip galvanized fittings for the string hardware
• Request a puncture-test certificate for the toughened glass shells