Performance comparison of common section insulators

Section insulators differ mainly in clearance size, mechanical class and application scenario:

• FYFH-1.6AT — 1.6 m clearance, Type A mechanical class; compact, for confined locations and lower tension.
• FYFH-1.8AT / 1.8BT — 1.8 m clearance; the most widely used general-purpose size for main line OCS.
• FYFH-2.0AT / 2.0BT — 2.0 m clearance; for higher voltage margins, polluted areas and heavy-load lines.
• GHT-FYFH — rigid catenary version for metro depots and tunnels where the contact wire is fixed.
• Metro 10TG / 20TG — DC traction versions for urban rail with 750 V / 1500 V supply.

Selection notes: confirm the contact wire and messenger wire tension to choose Type A (16.5 kN working load) or Type B (31.5 kN); confirm the clearance against the designed insulation distance; for polluted or coastal sites choose the larger clearance or the creepage-enhanced variant.