Apr 2013
Electricity Transmission
Sulphur in Oil Trial
Apr 2013
National Grid Electricity System Operator
National Grid TO Innovation Team
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Innovation Funding Incentive
Health and Safety
This project deals with the issue discussed in Risk Register item AM 138 and OESB 9/08. Following the failure of a supergrid transformer due to corrosive sulphur formation it became clear that National Grid was more exposed to the risk of this globally-experienced phenomenon than previously thought.

The issue is debated frequently at numerous conferences and there is much information given with little agreement between contributors. In particular the ability of standard oil regeneration techniques to remove the sulphur problem has been the subject of much disagreement with most of it based on theory rather than practical knowledge.

National Grid has some regeneration capability in a 20 year old rig and two newer hybrid units with some regeneration capability.

A new dedicated regeneration rig should be developed with a supplier of regeneration technology with unique features to enable high speed capability available for online sulphur removal of energised transformers. On line equipment is used worldwide but would not meet the rigorous UK safety requirements.

The objectives of this project are:

  • To trial on a selection of transformers/reactors the possibility of removing corrosive sulphur through oil reclamation and the addition of inhibitor in the oil.

  • To identify a strategy to manage National Grid's oil filled equipment to prevent the unnecessary failure of an asset due to corrosive sulphur.

To provide a future strategy that could be implemented worldwide if successful and therefore enhance our reputation in this field.