Refurbishment gives power station a new lease of life
16 March 2009
More than 100 ABB actuators, some of which have been installed since 1977, are getting a new lease of life in a refurbishment project at Tilbury Power Station.
Refurbishment project gives power station a new lease of life
The actuators have already outlasted the typical service life of most similar equipment, and their long-term reliability played a key part in the decision to opt for refurbishment rather than renewal.
Refurbishing the existing actuators is a cost-effective option for station owner RWE npower, and enables engineers to work with familiar equipment that has proved effective and reliable over many years.
“It is quite unusual for this kind of equipment to have such a long service life,” admited control and instrumentation engineer Frank Gamble. “The electric actuators were originally purchased from Hartmann and Braun, but they’re now ABB products. The refurbishment was actually carried out at the same factory in Germany where the actuators were originally built.” Hartmann and Braun became part of the ABB family in 1999.
The gearboxes at the heart of the refurbished units remain the same, but the separate amplifiers that used to drive the actuators are now obsolete, so ABB has replaced them with new motors and electronics. “We looked carefully at the options of replacing or refurbishing the actuators and the easiest option was to have them refurbished. It was cost-effective and saved us lots of time because we didn’t have to build new mountings or connections,” said Gamble.
Tilbury is a coal-fired power station next to the River Thames. It is capable today of generating over 1400 MW of electricity, enough to serve 80% of the population of Essex. One of the site’s original four generating units was mothballed in the late 1990s and this made scheduling the actuator refurbishment work relatively easy. “We effectively had a spare set of actuators,” said Gamble. “First we sent these for refurbishment and then we swapped them onto one of the live units during the next planned overhaul. It’s a rolling programme, with two out of three units now complete and the third unit due for completion during a planned overhaul in April 2008.”
The refurbished actuators cover a wide range of sizes and applications, some of which are very arduous. “For example, turbine speed control is a demanding application in which the actuator is moving all the time,” said Gamble. “Others are outdoors and exposed to the weather, but they’ve been very reliable over all these years.”
ABB’s electric actuators are widely used in power stations throughout the UK. All ABB actuators offer continuous control with a virtually wear-free operation, as well as the highest positioning accuracy and stability available, regardless of positioning time. Even continuously operating ABB actuators can perform maintenance free for long periods, making them ideal for industries such as power generation, in which plants typically operate for extended intervals between shutdowns.
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