DC 0079 - Frequency Changes during Large Disturbances and their effect on the total system - Phase 2

As of 1 October 2017 Grid Code Modifications GC 0036 and GC 0079 have now been superseded by Distribution Code Modification DC 0079.

Please note: all documents on the Grid Code GC 0079 web page will remain accessible as an archive to this new Distribution Code website area. As of 01 October 2017 all new documentation for Modification DC 0079 will only be available on the Distribution Code website. Access to the GC 0079 web page can be found here - http://www2.nationalgrid.com/UK/Industry-information/Electricity-codes/Grid-code/Modifications/GC0035-GC0079/

DCRP DC 0079 working group - Terms of Reference

Reports to Authority

REPORT TO AUTHORITY

Report to Authority DC0079 (Phase 2) - 27 March 2018

The purpose of this report is to assist the Authority in its decision to implement the proposed modifications to the Distribution Code Engineering Recommendations G59 and G83. The proposed modifications were subject to industry consultation in August 2017 and February 2018. During the August Consultation no response was received from manufacturers of type tested plant. As a result a second consultation was undertaken in February 2018 and one response was received from a type tested plant manufacturer. The manufacturer did not object to the proposal but proposed a delay in the implementation date.

It is recommended that modifications be made to Distribution Code and Engineering Recommendations G59 and G83 to mandate that all type tested generators commissioned on or after July 2018, demonstrate stability for appropriate RoCoF and vector shift disturbances. The report recommends:

a) That the rate of change of frequency (RoCoF) criterion used for Loss of Mains protection must be 1 Hzs per second with a definite time delay of 500ms

b) That vector shift protection technique should not be used as Loss of Mains protection for type tested generators and that generation must not trip for vector shifts of up to 50ยบ

c) That type tested generation includes stability tests to prove immunity to RoCoF and vector shift less than the above criteria.

Report

Report Annexes

Decision of Authority - 3 May 2018

REPORT TO AUTHORITY

Report to Authority DC0079 (Phase 1) - 4 December 2017

The purpose of this Report is to assist the Authority in its decision to implement the proposed modifications to the Distribution Code and Engineering Recommendations G59. The proposed modifications were subject to industry consultation in August 2017. Responses from this consultation show that the industry is in favour of these modifications.

The Distribution Code Review Panel recommended that modifications are made to the Distribution Code and Engineering Recommendations G59 to mandate that all non type tested embedded generators with a commissioning date on or after 1 February 2018 comply with the following:

  1. That where rate of change of frequency (RoCoF) protection is used as Loss of Mains protection, the applied setting should be 1Hzs-1 with a definite time delay of 500ms.
  2. That all generation using discrete relays (non- type-tested) as part of their loss of mains technique should demonstrate stability for appropriate RoCoF and vector shift disturbance
  3. That vector shift protection technique should not be used as Loss of Mains protection for generators using discrete relays as part of loss of mains protection scheme.

Report

Report Annexes

DECISION OF AUTHORITY - 15th December 2017

The Authority has approved this modification. Full details of Ofgem's decision can be found in their decision letter which can be found here. The resultant modifications to the Distribution Code and Engineering Recommendation G59-3/3 will become effective from 1 February 2018.

2017 Meeting Dates

Work Group Meeting Dates 2017

October

Agenda

Papers

Actions

November

Agenda

Papers

Actions

December

Agenda

Papers

Minutes and actions