Overhead Transmission Lines
Transmission lines are built once and maintained for thirty years, so the insulator decision is really a maintenance decision taken decades in advance.
What gets in the way
The four problems this sector brings us
String reliability over decades
A disc with a high deterioration rate turns a planned inspection interval into an unplanned outage. Our U70 series publishes annual deterioration rates of 0.04, 0.01 and 0.005 %.
Coupling discipline across a fleet
Long lines get built in sections by different contractors. We supply the same 70 kN disc in 16 mm and 16C couplings so a network can standardise electrically without forcing one coupling everywhere.
Tender compliance
Each batch ships with quality certificates, material certificates and test reports, which is what project acceptance actually asks for.
Delivery against a construction programme
Stringing crews are the expensive resource. Bulk order logistics are planned per project, with real-time tracking, so discs land before the towers are ready rather than after.
Recommended products
What we usually supply here
70 kN cap-and-pin porcelain disc, 146 mm spacing, 320 mm creepage, 16C coupling.
View specifications
70 kN cap-and-pin porcelain disc, 146 mm spacing, 320 mm creepage, 16 mm coupling.
View specifications
Porcelain line post, 160 mm shed diameter, 305 mm high, 400 mm creepage, 8 kN cantilever.
View specificationsAnswers
Overhead Transmission Lines: questions we are asked
What voltage levels do you supply for?
Our core voltage capability covers systems up to 500 kV AC and 400 kV DC. The products listed on this site are the distribution and sub-transmission range; send us your line voltage and we will confirm what we can supply.
How many discs per string should we plan for?
As a planning reference, around 10 units per string at 110 kV and 20 or more at 500 kV, adjusted for pollution class and altitude. We will work the configuration through with your line design.
Do you provide on-site support during stringing?
For large projects we send engineers for on-site installation, debugging and construction guidance.
Working on a overhead transmission lines project?
Send the line data and quantity schedule. Our engineers will come back with a selection, a documentation package and a delivered price.