KHIA ID: 4222
Industry: Power (POWR)
Application: VPF-Valves, Pipes and Fittings (VPF)
Substrate: Mild Steel
Customer Location: Electricity Substation, UK
Application Date: September 2012

Belzona® 1221 (Super E-Metal)

Belzona® 1161 (Super UW-Metal)

Belzona® 5831 (ST-Barrier)

Problem: For several years, the transformer had been suffering from extremely high discharges of transformer oil. Following full survey, oil discharges were evident at many of the flange and bolt joints on equipment located in both the interior and exterior of the noise enclosure. A root cause and contributory to the oil leaks were the high voltage and low voltage bushings located to the noise enclosure rooftop.
Photograph Descriptions
  1. Three HV bushings during survey
  2. LV bushing following substrate preparation and masking bolts
  3. LV bushing following the removal of one disposable former
  4. HV bushing completed including the encapsulation of bolt heads and coating with Belzona® 5831 for long term protection
Application Situation
Exterior/rooftop of Super Grid Transformer HV & LV bushings
Application Method
Application was carried out in accordance with modified versions of Belzona Know-How System Leaflets VPF-8 & 11. After preparing the surfaces active leaks were sealed with Belzona® 1291 or Belzona® 1221  The flange joints were then sealed by applying Belzona® 1161 incorporating Belzona® 9341 (Reinforcement Tape). The bolt and nut heads together with the male studs were fully encapsulated using disposable formers containing Belzona® 1161. Once cured, the formers were removed and all prescribed repair areas were coated with Belzona® 5831. 
Belzona Facts
Six bushings were successfully sealed and in recharging the transformer with oil to the correct level, the bushings did not show any visual evidence of leaking.