{
  "url": "https://openlegislation.uk/eu-regulation-2017-1485/article-139",
  "json_url": "https://openlegislation.uk/eu-regulation-2017-1485/article-139.json",
  "legislation": "eur/2017/1485",
  "legislation_title": "Commission Regulation (EU) 2017/1485 of 2 August 2017 establishing a guideline on electricity transmission system operation (Text with EEA relevance)",
  "legislation_url": "https://openlegislation.uk/eu-regulation-2017-1485",
  "path": "article/139",
  "kind": "article",
  "number": "139",
  "heading": "Basic structure",
  "text": "1. All TSOs of the GB synchronous area shall specify the load-frequency-control structure for the synchronous area in the synchronous area operational agreement. Each TSO shall be responsible for implementing the load-frequency-control structure of the GB synchronous area and operating in accordance with it.\n2. The load-frequency control structure of the GB synchronous area shall include:\n(a) a process activation structure in accordance with Article 140; and\n(b) a process responsibility structure in accordance with Article 141.",
  "extent": "E+W+S+N.I.",
  "status": null,
  "version": "current",
  "annotations": [
    {
      "type": "F",
      "label": "F1",
      "text": "Words in Art. 139(1) substituted (E.W.S.) (31.12.2020) by The Electricity Network Codes and Guidelines (System Operation and Connection) (Amendment etc.) (EU Exit) Regulations 2019 (S.I. 2019/533), reg. 1(2), Sch. 1 para. 89(2)(a) (as amended by S.I. 2020/1016, regs. 1(2), 6(2)); 2020 c. 1, Sch. 5 para. 1(1)"
    },
    {
      "type": "F",
      "label": "F2",
      "text": "Words in Art. 139(1) substituted (E.W.S.) (31.12.2020) by The Electricity Network Codes and Guidelines (System Operation and Connection) (Amendment etc.) (EU Exit) Regulations 2019 (S.I. 2019/533), reg. 1(2), Sch. 1 para. 89(2)(b) (as amended by S.I. 2020/1016, regs. 1(2), 6(2)); 2020 c. 1, Sch. 5 para. 1(1)"
    },
    {
      "type": "F",
      "label": "F3",
      "text": "Words in Art. 139(2) substituted (E.W.S.) (31.12.2020) by The Electricity Network Codes and Guidelines (System Operation and Connection) (Amendment etc.) (EU Exit) Regulations 2019 (S.I. 2019/533), reg. 1(2), Sch. 1 para. 89(3) (as amended by S.I. 2020/1016, regs. 1(2), 6(2)); 2020 c. 1, Sch. 5 para. 1(1)"
    }
  ],
  "outstanding_effects": [],
  "provenance": {
    "source": "legislation.gov.uk",
    "source_url": "https://www.legislation.gov.uk/eur/2017/1485/article/139",
    "retrieved_at": "2026-11-01T14:44:42.168103+00:00"
  },
  "licence": "Open Government Licence v3.0",
  "licence_url": "https://www.nationalarchives.gov.uk/doc/open-government-licence/version/3/",
  "attribution": "Contains public sector information licensed under the Open Government Licence v3.0. Source: legislation.gov.uk, The National Archives."
}