{
  "url": "https://openlegislation.uk/eu-regulation-2014-548/annex-II/division-2",
  "json_url": "https://openlegislation.uk/eu-regulation-2014-548/annex-II/division-2.json",
  "legislation": "eur/2014/548",
  "legislation_title": "Commission Regulation (EU) No 548/2014 of 21 May 2014 on implementing Directive 2009/125/EC of the European Parliament and of the Council with regard to small, medium and large power transformers",
  "legislation_url": "https://openlegislation.uk/eu-regulation-2014-548",
  "path": "annex/II/division/2",
  "kind": "division",
  "number": null,
  "heading": "Calculation methods",
  "text": "The methodology for calculating the Peak Efficiency Index (PEI) for medium and large power transformers referred to in Tables I.4, I.5, I.7, I.8 and I.9 of Annex I is based on the ratio of the transmitted apparent power of a transformer minus the electrical losses to the transmitted apparent power of the transformer. The calculation of PEI shall use state-of-the-art methodology available in the latest version of the designated standards for medium and large power transformers.\nThe formula to be used for the Peak Efficiency Index calculation is:\nWhere:\nP 0 is the no load losses measured at rated voltage and rated frequency on the rated tap\nP c0 is the electrical power required by the cooling system for no load operation, derived from the type test measurements of the power taken by the fan and liquid pump motors (for ONAN and ONAN/ONAF cooling systems P c0 is always zero)\nP ck (k PEI ) is the electrical power required by the cooling system in addition to P c0 to operate at k PEI times the rated load. P ck is a function of the load. P ck (k PEI ) is derived from the type test measurements of the power taken by the fan and liquid pump motors (for ONAN cooling systems P ck is always zero).\nP k is the measured load loss at rated current and rated frequency on the rated tap corrected to the reference temperature\nS r is the rated power of the transformer or autotransformer on which P k is based\nk PEI is the load factor at which Peak Efficiency Index occurs.",
  "extent": "E+W+S+N.I.",
  "status": null,
  "version": "current",
  "annotations": [
    {
      "type": "F",
      "label": "F1",
      "text": "Substituted by Commission Regulation (EU) 2019/1783 of 1 October 2019 amending Regulation (EU) No 548/2014 on implementing Directive 2009/125/EC of the European Parliament and of the Council with regard to small, medium and large power transformers (Text with EEA relevance)."
    },
    {
      "type": "F",
      "label": "F2",
      "text": "Words in Annex 2 substituted (31.12.2020) by The Ecodesign for Energy-Related Products and Energy Information (Amendment) (EU Exit) Regulations 2019 (S.I. 2019/539), reg. 1(3), Sch. 2 para. 22(7)(b) (as substituted by S.I. 2020/1528, regs. 1(2), 8(c)(vii))"
    }
  ],
  "outstanding_effects": [],
  "provenance": {
    "source": "legislation.gov.uk",
    "source_url": "https://www.legislation.gov.uk/eur/2014/548/annex/II/division/2",
    "retrieved_at": "2026-11-01T14:47:38.642843+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."
}