Asset Health Reviews to Manage Remaining Life

For many utilities the asset base is ageing at a time when the business focus is on system availability and energy not supplied. For the major plant items, such as generators, cables and transformers, where failure leads to long term unavailability, it is important to be able to define the risks of future operation. The processes used to achieve this have many common threads across the technologies, but in this paper we concentrate on the transformer asset base and the methods developed and used in UK. Having established the common weaknesses with the design groups, an annual review assess each individual unit, taking into account all evidence received over the past year, to identify if these weaknesses are becoming manifest. This review indicates those units requiring further investigation, usually involving off-line testing. The overall aim is to identify and rank the stock in terms of failure risks. Thus condition assessment should define the likelihood of failure and the second element of risk is to assess the system consequence of failure and re-work the ranking in terms of total risk exposure. This then allows criticality based decisions for managing operating and capital expenditure.