VGB POWERTECH 7 (2021) - International Journal for Generation and Storage of Electricity and Heat

VGB PowerTech 7 l 2021
Avoid cost-intensive oil change in a hydropower plant
VGB oil laboratory tests oil blends to
avoid cost-intensive oil change in a
hydropower plant
Kurzfassung
Ölmischbarkeitsversuche im VGB-Öllabor
vermeiden kostenintensiven Ölwechsel
Die Energiewende und die damit verbundene
vorrangige Einspeisung erneuerbarer Energie
erfordert von konventionellen, disponiblen Erzeugungsanlagen
ein hohes Maß an Flexibilität.
Wasserkraft als erneuerbarer Energieträger
zeichnet sich durch die Rund-um-die-Uhr-Verfügbarkeit
und Planbarkeit als eine verlässliche
Größe in der Energieversorgung aus. Wasserkraftwerke,
bzw. deren Komponenten wie Turbine
und Hydrauliksysteme sowie Antriebe für
Tore, Schieber und Klappen, benötigen wie alle
Kraftwerke und Windkraftanlagen große Mengen
an Schmierölen und Schmierstoffen. Die
Überprüfung dieser Stoffe hat einen ganz besonderen
Stellenwert. Die regelmäßige Kontrolle,
und dadurch frühzeitiges Erkennen von Anlagenstörungen
und sich anbahnenden Schäden,
gewährleisten den sicheren und reibungslosen
Betrieb der Wasserkraftwerke. Ein vollständiger
Ölwechsel, der nur bei Anlagenstillstand
durchgeführt werden kann, ist mit einem
hohen Kosten- und Personalaufwand verbunden.
Er ist daher nicht das erste Mittel der Wahl.
Das VGB-Öllabor unterstüzt die VGB-Mitglieder
und Kunden bei der Identifikation von Ölen, die
sich mit den noch im Betrieb befindlichen Ölen
mischen lassen und dabei den sicheren und zuverlässigen
weiteren Anlagenbetrieb ermöglichen.
l
The energy transition and the associated
priority feed-in of renewable energy require
a high degree of flexibility from conventional,
plannable generation plants,
which is often associated with serious
problems due to the design of conventional
thermal power plants (frequent load
changes, start-up and shut-down, etc.). In
contrast to volatile renewables (wind and
solar), hydropower is a renewable source
of energy that is reliably supplying power
due to its base load capability and plannability,
i.e., some of the most important requirements
– namely security of supply and
system stability – are met by hydropower.
Service for oil ensures safe
operation
Similar to any conventional power plant,
hydropower plants and their components
such as turbines and hydraulic systems as
well as drives for gates, slides and flaps, require
large quantities of lubricating oils.
Often, several thousand litres of lubricating
oil are used in the entire plant. Due to
the low thermal load in hydropower, these
oils can usually be operated for very long
lifetime of several decades (20 to 40 years
on average, F i g u r e 1 ). Regular inspections
and thus the early detection of system
malfunctions and impending damage ensure
the safe and smooth operation of power
plants and prevent unscheduled unavailabilities
and repairs.
Particularly oil losses as a result of small
leakages, require regular refilling of oil in
order to maintain the oil level needed.
However, operators and maintenance engineers
are often faced with major challenges
in this regard: The original oils used according
to design are often no longer available
on the market. The procurement of
replacement oils is difficult, and often
there are also no longer any data sheets
available that can provide information on
the composition of the original oil, in order
to be able to use equivalent oils according
to the properties of the original materials.
Oils cannot necessarily be blended with
each other. Different oil qualities can cause
incompatibilities, which in turn pose considerable
risks, e.g. loss of oil properties or
tearing of the oil film. This can lead to damage
ranging from bearing damage to machine
damage up to total turbine failure. In
order to avoid a complete oil change, the
VGB Oil Laboratory (F i g u r e 2 ) supports
VGB members and customers in identifying
oils that can be blended with the oils still in
use and guarantee safe and reliable further
plant operation.
Authors
Further information
VGB PowerTech Service GmbH
Essen, Germany
Oil laboratory
Gelsenkirchen, Germany
Heiko Fingerholz
heiko.fingerholz@vgb.org
Dr. Christian Ullrich
Head Technical Services
christian.ullrich@vgb.org
Fig. 1. Mineral oils change under the influence of temperature, humidity, air and metals such as
copper or iron.
85