Materials Expert, Stephen Rowbotham returned to the Philippine Coal Plant User Group to present at the 27th Technical Forum in October.
In his presentation, ‘Life Limiting Damage Mechanisms in Generators’ Stephen gave an overview of the different types of generators in power stations and the common causes of failures. He highlighted that a power generator should have a lifespan of many years, even decades but, if and when it does fail, it can lead to downtime of over a year, with property damage and business interruption into the millions of pounds.
Stephen explained the different types of generator failures that Hawkins has investigated, with the most common being generator fatigue. He explained what ‘fatigue’ means from an engineering perspective, and how problems occur. Conductors are often made from copper, which, despite being an excellent conductor, lacks the structural integrity of steel. Stephen discussed how fatigue differs between steel and copper, noting that the two major failure mechanisms are low cycle and high cycle fatigue, and that the main difference between these mechanisms, is the number of cycles to failure.
He elaborated on the fatigue issues associated with rotor copper explaining that the rotor design is complicated as the copper tends to thermally expand. He provided an overview of the different types of rotor corners noting that rounded corners are less prone to stress concentration than square corners, but are more expensive to manufacture, and can still occasionally crack. Stephen concluded by sharing details of the techniques that investigators use when looking for cracks in such failures.
Stephen has extensive global experience in the power and energy industry, helping loss adjusters, insurance companies and owners/operators investigate incidents in power plants ranging from renewables to thermal generation assets. His experience includes both static and rotating components, condition assessment of gas and steam turbines, and outage support for operators. If you would like Stephen, or a Hawkins expert from any other discipline to investigate an incident for you, contact us for a free consultation.
