In 2021, electro mechanical engineering specialist Houghton International carried out the repair and rewind of an 850kW direct-drive wind turbine generator. Renew found out more about the project.
The Enercon E48 wind
turbine was erected and
commissioned in 2019
on a farm in the village
of Llanwnnen in Ceredigion, Wales,
by Grannell Community Energy, a
locally-funded Community Benefit
Society. It was purchased from a
wind farm in the Netherlands, where
it had previously been in operation
In late 2020 the turbine
failed in service due to an earth
fault, and Grannell Community
Energy approached Houghton
International to carry out
repair work. Based in North
England, Houghton International
accommodated the 26-tonne
generator in its large machine
repair shop, which is specifically
designed for large-scale projects.
Lindsay Thomas, Director
at Grannell Community Energy, commented: “As a community
energy group, we have invested
significant time, effort and funds
into our wind turbine project, so
when it came to repairs, it was
particularly important to us to
find a repairer that could offer the
highest quality of service.
“From our
first contact
with Houghton
International, we
were impressed
by their
professionalism,
enthusiasm and
support for the
project. Not only
did they have
the facilities to
accommodate a project of this
size, but they also gave us full
confidence in their experience and technical expertise.”
Considering the age and
condition of the asset, and
previous works carried out on the
turbine, Houghton International’s
project team recommended a
full rewind of both the rotor and
stator to minimise the risk of
further faults
and extend the
operational
lifespan of the
turbine.
Houghton
International
has developed
a range of
processes and
intellectual
property inhouse, several examples of which
were used during this project, as
Chris Measor, Winding Assistant Manager at Houghton International,
explained: “We agreed with the
customer that we would make
improvements to the insulation
systems on both the rotor and
stator to give them peace of mind
of a long-lasting, quality repair.
“To rewind the DC pole shoes
from the rotor, we used a system
we had first developed for use on
high-speed trains, which is tried
and tested with a proven track
record. Whilst running on the
railways, this system is exposed
to high levels of moisture and
temperature extremes, making it
an ideal choice for the conditions
the wind turbine is likely to see.
“We also uprated the insulation
on the stator to a Class 3 enamel
copper, which has a breakdown
voltage of about 15,000V. The
generator runs at around 480V, so
this gives it a very high dielectric
strength.”
The project was the first
of its kind to be completed at
Houghton International, requiring
the manufacture of a bespoke frame and
motorised jig
for the winding
of over 50 miles
of continuous
copper wire from
three drums.
Houghton
International
provided
regular reports
and progress
updates to
Grannell
Community
Energy throughout the project and
continued to deliver support after
the turbine had been transported
back to Wales for reinstallation.
Lindsay concluded: “The support
from Houghton International has
been excellent even after the
generator left their facility. We
were able to come back to them
with further questions during the
installation, and we are reassured
to know they are on hand in future
for any spares or maintenance
support needed.
“Having recently reinstalled the
generator, initial impressions are
that it is generating exceedingly
well, and we are optimistic it
will meet our most ambitious
projections for power generation.
As a result of the comprehensive
and diligent work carried out, we
effectively have a brand new turbine
in operation, and we have every
confidence that it will meet its 20-
year lifespan expectation.”
Houghton International