Retrofitting Creepage on Flashover Prone Outdoor Terminations

Client Background

A coastal substation operator in the Middle East had a recurring flashover problem on outdoor 33 kV terminations. Failures clustered in the weeks after the first rain following a long dry period which is the classic signature of pollution flashover.

Project Challenge

Fix the flashover problem across 96 terminations without the cost and outage time of rebuilding every termination from the cable up.

Customer Pain Points

• Repeated outages traced to pollution flashover not to cable or accessory defects
• Rebuilding 96 terminations would have taken an unacceptable amount of outage time
• Salt and sand deposition builds a conducting film faster than a normal cleaning cycle removes it
• The existing terminations were electrically sound which made a full rebuild hard to justify

Our Solution

Y3 non tracking rain sheds were retrofitted over the existing terminations. Because sheds slide over a finished termination and shrink into place with mastic collars, no electrical layer had to be disturbed. Shed count was set at six per phase against the site pollution class rather than the two or three a normal inland site would need.

Manufacturing Process

Sheds were molded in our own tooling from the same non tracking compound family used in our C101 insulation. Mastic collars were factory applied so nothing had to be added on site.

Supply Chain Coordination

A single shipment covered all 96 terminations plus a ten percent spare allowance. Delivery was timed to arrive before the planned outage window opened.

Quality Control

Tracking and erosion resistance verified to ASTM D2303 at 2.5 2.75 3.0 and 3.25 kV. Colour fastness to light checked to IEC 60684-3 so the sheds would not chalk under desert UV.

Final Result

All 96 terminations were retrofitted inside two outage windows. Each termination took under twenty minutes. There have been no flashover events on the retrofitted terminations since.

Customer Benefit

The operator solved a recurring outage problem for the cost of a molded part rather than the cost of 96 new terminations and the outage time to install them.