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Reference Number NIA_UKPN0022
Title Global Earthing Systems (GES)
Status Completed
Energy Categories OTHER POWER and STORAGE TECHNOLOGIES(Electricity transmission and distribution) 100%;
Research Types Applied Research and Development 100%
Science and Technology Fields ENGINEERING AND TECHNOLOGY (Electrical and Electronic Engineering) 100%
UKERC Cross Cutting Characterisation Not Cross-cutting 100%
Principal Investigator Project Contact
No email address given
Eastern Power Networks plc
Award Type Network Innovation Allowance
Funding Source Ofgem
Start Date 01 March 2017
End Date 01 March 2019
Duration 24 months
Total Grant Value £483,000
Industrial Sectors Power
Region London
Programme Network Innovation Allowance
 
Investigators Principal Investigator Project Contact , Eastern Power Networks plc (99.998%)
  Other Investigator Project Contact , UK Power Networks (0.001%)
Project Contact , South Eastern Power Networks plc (0.001%)
Web Site http://www.smarternetworks.org/project/NIA_UKPN0022
Objectives The aims of the project are: Improve the knowledge of current flows and the earthing contribution from a nearby or surrounding network in terms of a global earthing system. Identify the tangible benefits and application of global earthing systems including the potential to reduce (or optimise) the cost of substation earthing. Trial various methods to decouple the local substation earthing system from the overall combined network earthing system. Develop a revised methodology and/or set of parameters to update UK Power Networks’ substation earthing design tool and earthing design standards. Produce an interactive training package on how to use the revised process. Publish a paper on the work undertaken to inform others and (via ENA or other forums) share amongst GB DNOs The project will be deemed successful if: The learning outcomes defined in "Objectives" are achieved. It can be shown that less earthing is required at distribution substations, when comparing the new substation earthing design tool with existing methods on a sample of sites.
Abstract Dense urban cable networks, by their very nature, create difficulties for earthing measurements. Given that earthing design relates directly to the safety of DNO staff and members of the public, it is important to have detailed and accurate measurements to confirm a) that a substation is safe and b) satisfies the requirement established by third party services and utilities with regards to earthing e. g. their metallic fences. In addition to the measurement difficulties, there is also a fundamental lack of understanding in the way that earth fault current flows within an HV interconnected cable network which is also termed a ‘global earthing system’. Theoretical benefits of such a system (earth resistance contribution and limitation of safety voltages) are often overlooked, or cannot be fully realised during the design of secondary (11kV) substations earthing systems due to lack of data. Currently, a number of assumptions are made during the earthing design of secondary substations, which err on the side of caution. Consequently, earthing systems may be overdesigned, i.e. they are more comprehensive than they need be. This leads to inefficiencies both at the design and installation stage, which potentially leads to more copper being installed and excavations being larger than necessary. This lack of knowledge and understanding about the earthing systems in the network may also lead to incorrect assumptions and inadequate designs. In some rare circumstances, earthing designs may be produced which are not adequate to ensure safety (i.e. may increase the likelihood of injury to staff or member of the public to unacceptable levels). A good understanding of network behaviour is necessary to demonstrate compliance with The Electricity Safety, Quality and Continuity (ESQC) regulation and other relevant regulations. The project will carry out following activities: Literature review to identify previous research work on global earthing systems. Measurements within different types of urban/suburban networks to obtain a better understanding of earth fault current flows and the overall performance of a global earthing system. Trialling of novel measurement methods to better de-couple the local system (under test) from the overall earthing system, and to explore contributions from parallel paths (e. g. sheath current flows via normally open points). Network modelling to validate the measurements and to develop an approach that can be used in every day earthing design.Note : Project Documents may be available via the ENA Smarter Networks Portal using the Website link above
Publications (none)
Final Report (none)
Added to Database 14/08/18