Vector Shift Initial Performance Assessment

Completed

Other Power and Storage Technologies(Electricity transmission and distribution)

Applied Research and Development

ENGINEERING AND TECHNOLOGY (Electrical and Electronic Engineering)

Not Cross-cutting
Sociological economical and environmental impact of energy (Consumer attitudes and behaviour)

Project Contact
National Grid Electricity Transmission

Network Innovation Allowance

Ofgem

01 February 2017

01 June 2017

4 months

£30,000

Power

London

Network Innovation Allowance

Project Contact, National Grid Electricity Transmission

Establish the relative performance of Vector Shift and RoCoF Loss of Mains techniques. A clear quantified measure of Vector Shift Loss of Mains protection performance relative to RoCoF for a set of known and agreed combinations of network and generation technology.

Distribution Companies need their customers to install "Loss of Mains" protection. The protection is intended to shut distributed generation down safely when a local island is detected. Inappropriate settings lead to either: Islands not being detected putting equipment and personnel at risk; or large numbers of small generators shutting down simultaneously in response to a widespread disturbance (e.g. a frequency incident or secured faults). There is evidence that the settings currently recommended in the Distribution Code are inappropriate and a system incident on 21st May 2016 provided supporting evidence of their impact on the operation of the total (or whole) electricity system. There is therefore a need to review Vector Shift settings used in Great Britain (GB). No information is available in GB or internationally which quantifies Vector Shift based Loss of Mains protection’s ability to detect power islands effectively or, discriminate between an islanding event or a network fault. An inability to conclude a review means the industry cannot agree an approach for Loss of Mains protection settings. Current settings cause £40m per year in Balancing Service costs. Extensive modelling of appropriate islanding scenarios and protection relay testing would ordinarily be required to recommend new Vector Shift setting which is resilient to network disturbances, and in terms of its ability to detect a genuine local power island. However, the GC0079 joint Grid Code and Distribution Code workgroup has developed a specification for an initial assessment which, if successful, will mean a complete assessment is not required. This initial assessment will evaluate whether Vector Shift protection is better or worse than RoCoF (Rate of Change of Frequency) techniques at detecting a power island. If it is worse, this demonstrates there is no good reason to use Vector Shift and it may be possible draw a conclusion that its use should be discontinued. This approach is feasible because of previous work which has quantified the performance of RoCoF based Loss of Mains protection techniques.Note : Project Documents may be available via the ENA Smarter Networks Portal using the Website link above

17/12/18