Transformer Upgrade Solutions

With an increasingly aged population of key assets in the electrical grid comes increasing scope for refurbishment funded by operational budgets as opposed to replacement funded by capital budgets. The lifetime of power transformers can be extended by refurbishment involving the upgrade of components such as tap changers, WTIs, PRDs, breathers, protection and control schemes and related cubicles/ kiosks. Refurbishment of transformers is viable if the transformer itself is deemed to have substantial remaining lifetime. This can be assessed using diagnostic measurements such as DGA of the oil, SFRA, tan-delta etc. Many asset owners are taking such measurements on a routine basis and are able to assign an asset health index to transformers. The health index may be dramatically improved by refurbishment strategies and can be much more economical and quicker than replacement. The on-load tap changer is a key component of the power transformer and is ultimately the only moving part in a substation. It is a mechanical device and therefore requires regular maintenance. Failure of a tap changer can result in replacement of the transformer itself due to the fact that replacement parts for the tap changer are often difficult to source due to its age. This is expensive and can have long lead times.

Most OLTCs in the UK are the bolt-on design which lends them nicely to replacement without modification of the transformer itself. Maintenance-free tap changers can be installed on existing transformers in place of problematic or failed units to give decades more operating lifetime for the transformer. This ultimately delays transformer replacement, significantly reducing expenditure and also removing the requirement for OLTC maintenance.

Fundamentals has experience in control system refurbishment services where complete tap changer control schemes are upgraded to modern standards.

The company has extended the scope of services to include replacement of other components associated with power transformers and can offer turnkey solutions for tap changer replacement to cover the following:

  • Site Surveys
  • Engineering, Design and Drawings
  • Site Installation
  • Commissioning