National Grid Electricity System Operator
National Grid TO Innovation Team
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Innovation Funding Incentive
There are varied types of power flow limitation in modern power systems. If the
problem can be solved by a relatively large increase in the thermal rating of an
overhead line, re-conductoring the line with High Temperature Low Sag (HTLS) conductor is a possible
solution. These conductors are capable of high temperature operation with
minimal change in electrical and mechanical properties and have low sag at high
temperature when compared to conventional conductors.
In order to increase a lines thermal rating without rebuilding or replacing its
structures and foundations, the original conductor can be replaced with a special
HTLS conductor having the a similar dimensions
and properties as the original, but which can be operated safely and reliably at
much higher temperatures with far greater ampacity.
The 3M Company was established in 1902 with $27 Billion Sales in 2010 over
80,000 employee’s world wide.
ACCR conductor has over 10 years service history with no reported failures in
service and no failures during installation. To date there are 90 successful
installations, in over 60 different countries, with more scheduled for 2011, 2012 &
2013. With the most recent installation being in National Grid USA, as part of the
Western Massachusetts Transmission Reinforcement Strategy, 3M are currently
investing in expanding manufacturing capacity to meet demand.
Key learning to be delivered by the project is the understanding of the
circumstances under which the Superconducting Fault Current Limiter (SCFL) can
be used to mitigate fault level issues which are a barrier to Distributed Generation
(DG) connection and how the SFCL can then be designed into and operated.
Specifically the following learning outcomes would be expected:
- Identification of network and physical circumstances where use of the SFCL
could be used to mitigate fault level issues and address potential future DG
- Identification of design, construction, commissioning, protection, control and
operational issues associated with use of such equipment. If the trial proves
successful in mitigating faults this could also reduce the need for transmission
reinforcements across GB
- Assessment of actual carbon benefits/confirmation of initial carbon case
- Assessment of impact of equipment on policies, codes of practice, section level procedures, financial authorisation processes (including the financial justification)
and identification of required revisions.
- Dissemination will be through the production of a manual that details
the new knowledge outlined above.
This project trials a specific piece of new equipment that has a direct impact on
the operation and management of the distribution system and potentially the
Phase 1. To identify suitable locations for the SFCL installation and undertake a
feasibility and systems readiness study to analyse the network, outline the
optimum application and specification, and confirm the business and carbon
cases. This has been completed.
Phase 2. To design, build, install and commission a three-phase 33kV SFCL on
the CE distribution network. It is proposed, subject to site surveys and
agreement with National Grid and other partner organisations, that the unit is
installed at a 275/33kV substation in South Yorkshire to limit the fault current to
within the rating of the 33kV switchgear. This is currently managed through an
operational management switching procedure which in some circumstances may
increase the risk of loss of supplies to customers.