{
  "url": "https://openlegislation.uk/eu-regulation-2017-1485/article-19",
  "json_url": "https://openlegislation.uk/eu-regulation-2017-1485/article-19.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/19",
  "kind": "article",
  "number": "19",
  "heading": "Monitoring and determination of system states by TSOs",
  "text": "1. Each TSO shall, in real-time operation, determine the system state of its transmission system.\n2. Each TSO shall monitor the following transmission system parameters in real-time in its control area, based on real-time telemetry measurements or on calculated values from its observability area ...:\n(a) active and reactive power flows;\n(b) busbar voltages;\n(c) frequency and frequency restoration control error of its LFC area;\n(d) active and reactive power reserves; and\n(e) generation and load.\n3. In order to specify the system state, each TSO shall perform contingency analysis at least once every 15 minutes, monitoring the transmission system's parameters defined in accordance with paragraph 2, against the operational security limits defined in accordance with Article 25 and the criteria for system states defined in accordance with Article 18. Each TSO shall also monitor the level of available reserves against the reserve capacity. When carrying out the contingency analysis, each TSO shall take into account the effect of remedial actions and the measures of the system defence plan.\n4. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .",
  "extent": "E+W+S+N.I.",
  "status": null,
  "version": "current",
  "annotations": [
    {
      "type": "F",
      "label": "F1",
      "text": "Words in Art. 19(2) omitted (E.W.S.) (31.12.2020) by virtue of 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. 20(2) (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": "Art. 19(4) omitted (E.W.S.) (31.12.2020) by virtue of 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. 20(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/19",
    "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."
}