A 55-year old Inverness-shire hydro power station is enjoying a new lease of life after a retro-fitting a new bespoke Brushless AC Exciter.
The existing commutator at the Mucomir station was suffering badly with uneven wear issues, due in part to the intermittent loading and the humid environment at the site.
Owned and operated by SSE, the Mucomir power station is a run of the river hydro facility which is fed from Loch Lochy.
The station – which has been in continuous operation since 1962 – is part of the Great Glen Hydro Group and the power plant comprises a Kaplan turbine driving a 3300V, 40pole, 150-rpm AC synchronous generator.
In addition to winning the contract to refurbish an existing generator stator and rotor, electrical contractor Quartzelec also designed and built a new AC brushless exciter to replace the old DC exciter to eliminate both the dust and maintenance burden plus significantly reduce the risk of extended outage resulting from brush and commutator wear.
David Swaffield, Quartzelec’s Lead Electrical Engineer on the retro-fit project said: “The slow 150rpm shaft speed of this turbine, presents its own challenge for the electrical machine design which, when combined with the limited access and available footprint along with the available cooling and the limited envelope, meant this project necessitated some significant engineering and a high pole-count – but we were more than up to the task.
“The new solution retains the original fan, shaft interfaces and housing while eliminating the risk and maintenance overhead of the original brush gear.”
Mucomir – one of a number of small stations built in the 1940s and 50s by the former North of Scotland Hydro Board – is run as part of the much larger Garry-Moriston hydro-electric scheme.
3 Nov 2017