Alternative Bus Bar Protection Solution
National Grid Electricity System Operator
National Grid TO Innovation Team
Click here to send a question to the contact.
Innovation Funding Incentive
Gas Distribution Networks
A policy for single digital bus bar protection has been employed on the National Grid Transmission network since 2002 either as a replacement system (for
duplicated high impedance schemes) and for all new build double bus bar
substations. These systems have a distributed architecture with remote bay units
(interfacing to the plant) for each protected circuit with ruggedized cross site fibre
connections to a central processing unit. Where a substation has a centralised
relay room (e.g. GIS) layout, the bay units are co-located in a suite of cubicles
and connected with a network of fibre patch cords.
A number of systems and versions have been installed from National Grid's
preferred protection suppliers and Alliances over the past 20 years and these
have required additional support through contracted Post Delivery Support Agreements (PDSA) to provide field staff
with the resources to manage faults and defects. A recent protection policy
change also requires a second (hot standby) central processing unit to be
deployed (with it own dedicated fibre connections) to better manage contingency
issues for central processing unit failures.
The systems installed to date have proven to be generally reliable; however
each system is bespoke to each supplier with a limited technical life, leading to
issues with future substation extensions and potentially the need to consider
equipment upgrades and early asset replacement of the complete system. This
will have major issues on future system access to carry out this work across a
Through work with CIGRE, contacts with other utilities and National Grid, United States, it
has been found that an alternative centralised bus bar protection system may
offer greater asset management benefits in the longer term, especially when
managed and supported by well trained internal staff.
This project is desk top evaluation of an alternative bus bar protection design
and the interface and application on the UK Transmission system.
This project aims to deliver an evaluation and desk top design solution of an
alternative digital bus bar solution architecture. This will help formulate a future
technical and procurement strategy for bus bar protection, potentially leading to
a pilot installation, evaluation and deployment as a replacement (or new) bus bar