Underground High Voltage Cables: Wiring Europe for the Future
In many of Europe's largest cities and
in areas where construction of overhead transmission
lines creates difficulties, high and extra-high voltage underground
electricity cable systems rated 220kV and above
have become part of the backbone of modern day
power transmission infrastructure. Although cables
have been in use for over half a century, today's
underground high voltage cables are leveraging
state-of-the-art technology and advanced design
to expand their reach and are increasingly becoming
an efficient and reliable alternative to overhead
lines. Learn how underground high voltage cables
are powering a changing world.
Take a look at the many benefits of underground
high voltage cables and learn how they can be
put to work for you:
If you are a cable specialist and are
interested in learning more details about underground
high voltage cables, choose from the topics below:
- Environmental: Information
about EMFs, land issues, recyclability, installation
impacts, and sensitivity benefits.
- Regulation: Details on basic
mechanisms, regulatory drivers, and incentives.
- Case Studies: Presentation
of reliability showcases, unstopping bottlenecks,
overcoming obstacles, and strategies for success.
- Cable Installation: Discussion
of stages such as production, installation,
system design, as well as historical findings.
- System Reliability: Information
about overload capacity, failure issues, technical
changes, and warranties and testing.
- Life Cycle: Details about
transmission losses, planning delays, and replacement
cycles.
Versatile
and Unique
Underground cables have unique properties
for transmitting power - they are out of sight,
often require only a narrow band of land to install,
emit no electric field and can be engineered to
emit no magnetic fields, have better power loss
characteristics and can absorb emergency power
loads. As a result, underground cables assist
the transmission of power across:
- Densely populated urban areas;
- Areas where land is unavailable or planning
consent is difficult;
- Rivers and other natural obstacles;
- Land with outstanding natural or environmental
heritage;
- Areas of significant or prestigious infrastructural
development; and
- Land whose value must be maintained for future
urban expansion and rural development.
(back
to top)
Cost
Effective Solution
In the past, the higher cost of underground
cables was a significant deterrent to their use.
However, with lower cost production methods, improved
technologies and increased reliability, the cost
differential between underground cables and overhead
power lines is narrowing. This means that power
project developers are more frequently turning
to underground cables as an economic and technically
effective alternative when physical obstructions
or public opinion hinder the development of networks.
Opportunity costs from lengthy planning delays
are reduced and the expense and complexity of
public legal cases are inimized.
Apart from the reduced visual impacts,
underground cables also offer lower maintenance
costs than overhead lines. They are also less
susceptible to weather-related issues such as
storm damage, interruptions, costs of storm damage
surveys and precautionary storm shutdowns. In
addition, underground cables contain high quantities
of copper, the most conductive engineering metal,
resulting in 30 percent lower power losses than
overhead lines at high circuit loads and improved system efficiency.
(back
to top)
Advanced Features
Offer Savings and Reliability
Today's cable manufacturers are able
to provide innovative and ustomized solutions
for the modern state-of-the-art power transmission
industry. Underground high and extra-high voltage
cables are equipped with new design features,
such as real-time monitoring, which make them
an effective and reliable alternative to overhead
lines.
Enhanced Technology
Cables for burial on land using extruded
insulation technology are taking the place of
traditional oil-filled cables because of significant
advantages that include:
- Easier installation and jointing;
- Better environmental compatibility and friendliness
in service;
- Reduced installation costs; and
- Reduced or practically zero maintenance.
(back
to top)
Increased
Reliability
Today's cable systems, using
cross-linked polyethylene (XLPE) as the primary
insulation material, have been performance
tested to ensure reliability. New cables based
on this technology have been running for over
20 years with an excellent reliability record.
(back
to top)
Reduced
Transmission Losses
Underground extra-high voltage
cables generally have more efficient copper conductors
and operate at lower temperatures than overhead
lines. These properties combine to transmit energy
to end users as efficiently as possible, which
is especially important for remote renewable and
low carbon generators. Reducing these power transmission
losses makes a valuable contribution to lowering
greenhouse gas emissions.
(back
to top)
Advanced
Installation Techniques
With new burial and jointing
techniques, underground cable projects that once
took years to complete can now take only months
to install. Through the use of directional drilling
and "trenchless" burial techniques,
cable manufacturers are applying leading edge
design know-how to dramatically reduce installation
times. In some installations, where it is not
possible to trench or duct the cables, underground
tunnels have been built to carry the cables. In
some cases, significant cost savings have been
made by placing cables in existing tunnel systems.
(back
to top)
Improved
Monitoring
To reduce outage time, power
system operators can monitor underground cables
through built-in temperature sensors. The sensors
allow the cable to safely accept enormous emergency
power overloads when other parts of the network
are down. This means that the overall system becomes
more robust and supply is maintained. In the rare
event of a cable fault, generally caused by external
disturbance, advanced monitoring of temperature
and integrity in real time will allow faults to
be located and repairs to be carried out in a
much shorter timeframe than in the past.
(back
to top)
Powering
a Changing World
Power markets across Europe
are being challenged by four often conflicting
drivers:
- Requirements to carry more power generated
from remote renewable and nuclear sources of
energy;
- Requirements to increase the interconnection
capacity between countries;
- Requirements to increase system security while
replacing ageing transmission assets; and
- Increased planning delays for new overhead
transmission infrastructure due to heightened
public interest in environmental matters.
Transmission companies and cable
manufacturers are searching for new ways to manage
the response to these drivers.
By targeting problem locations
for overhead transmission projects at the planning
stage and by proposing underground cable solutions,
developers can:
- Gain support from stakeholders who would otherwise
oppose transmission projects;
- Reduce or eliminate planning delays so projects
are completed on reliable timescales to satisfy
investors, customers and regulators;
- Leverage the improved lifecycle cost of underground
cables to control costs on the overall project;
and
- Demonstrate to investors that business risk
from emerging environmental and corporate social
responsibility drivers is being managed effectively.
(back
to top)
|
