CLC/TR 50453:2007
(Main)Evaluation of electromagnetic fields around power transformers
Evaluation of electromagnetic fields around power transformers
This Report provides guidance for the evaluation of electromagnetic fields around power transformers. This Report applies to power transformers covered by EN 60076 series with the following characteristics: - apparent rating P: 5 kVA P 1 000 MVA - insulating level, according to EN 60076-3: • high voltage winding: Um from 7,2 kV to 525 kV • low voltage winding: Um up to 525 kV Reactors are excluded from the present Report. Continuous conducted and radiated emissions are considered for power transformers operating under nominal working conditions of voltage and current. Fault conditions and low occurrence transient events, such as - short-circuits, - lightning and switching transients, - overloads (inrush currents, etc.), - overvoltages, - tap-changer operations, are not considered as normal working conditions. Immunity conditions are considered to ensure the power transformer operates as intended in its normal working environment. The immunity capability of the power transformer is considered for steady state and transient working conditions.
Bewertung von elektromagnetischen Feldern in der Umgebung von Leistungstransformatoren
Evaluation des champs électromagnétiques autour des transformateurs de puissance
Le présent rapport fournit des lignes directrices concernant l’évaluation des champs électromagnétiques autour des transformateurs de puissance. Ce rapport s’applique aux transformateurs couverts par la série EN 60076 avec les caractéristiques suivantes : – caractéristiques apparentes P: 5 kVA P 1 000 MVA – niveau d’isolement selon EN 60076-3 : • enroulement haute tension: Um de 7,2 kV à 525 kV • enroulement basse tension : Um jusqu’à 525 kV Les réactances sont exclues du présent rapport. Les émissions continues conduites et rayonnées sont prises en compte pour les transformateurs de puissance qui fonctionnent dans les conditions de service nominales de tension et de courant. Les conditions de défaut et les évènements transitoires dont la probabilité est faible, comme – les courts-circuits – les transitoires de foudre et de manœuvre, – les surcharges (courants d’appel, etc), – les surtensions, – le fonctionnement du changeur de prise, ne sont pas considérés comme des conditions normales de service. Les conditions d’immunité sont examinées pour assurer que le transformateur de puissance fonctionne comme prévu dans son environnement de service normal. Les capacités d’immunité du transformateur de puissance sont examinées pour les conditions continues et les conditions de service transitoires.
Ocenitev elektromagnetnih polj okoli elektroenergetskih transformatorjev
General Information
- Status
- Published
- Publication Date
- 15-May-2007
- Technical Committee
- CLC/TC 14 - Power transformers
- Drafting Committee
- IEC/TC 14 - IEC_TC_14
- Parallel Committee
- IEC/TC 14 - IEC_TC_14
- Current Stage
- 6060 - Document made available - Publishing
- Start Date
- 16-May-2007
- Completion Date
- 16-May-2007
- Mandate
- BC-01-87 - BC-01-87
Overview
CLC/TR 50453:2007 - Evaluation of electromagnetic fields around power transformers is a CENELEC technical report that gives guidance for assessing electromagnetic fields (EMF) and electromagnetic compatibility (EMC) aspects of power transformers covered by the EN 60076 series. It applies to transformers with apparent ratings from 5 kVA to 1 000 MVA, high-voltage winding insulation Um from 7.2 kV to 525 kV, and low-voltage winding Um up to 525 kV. Reactors are excluded. The Report focuses on continuous radiated and conducted emissions under nominal operating voltage/current; high‑impact fault events (short-circuits, lightning/switching transients, inrush, tap‑changer operations) are not treated as normal working conditions. Immunity considerations are included to ensure transformers operate correctly in their intended electromagnetic environment.
Key Topics & Requirements
- Scope and applicability: transformer types, voltage and rating limits, exclusions (reactors, rare fault conditions).
- Radiated emission:
- Power‑frequency magnetic fields: dominant contribution often from LV terminals and external busbars; guidance on reduction (shielding, enclosures).
- Power‑frequency electric fields: primarily from energized conductors and busbars; negligible for screened cable and enclosed liquid‑immersed units.
- Radio‑frequency fields: mainly from corona and partial discharges on HV connections; inner transformer RF sources are generally negligible.
- Conducted emission:
- Harmonics and no‑load current characteristics noted; purchaser requirements may apply.
- Immunity:
- Ensures control devices and protection operate in expected electromagnetic environments.
- Immunity to transient overvoltages is demonstrated by EN 60076‑3 tests; other continuous overvoltages or extreme harmonics must be agreed between purchaser and supplier.
- Calculation methods: Informative Annex A (power‑frequency magnetic field) and Annex B (electric field) provide practical calculation methods for simple busbar and conductor geometries.
Applications
- Use this Report when assessing EMI/EMC impacts of power transformer installations, planning substations, or specifying transformer procurement and site layout.
- Practical for:
- Transformer manufacturers and designers (EMC guidance during design)
- Transmission and distribution utilities (site planning, mitigation)
- EMC engineers and consultants (field assessment, shielding strategies)
- Safety and compliance teams (evaluating exposure and interference risks)
Related Standards
- EN 60076 series (Power transformers)
- EN 60076‑3 (Insulation levels / overvoltage tests)
- EN 61000 series (Electromagnetic compatibility)
- EN 55016 / CISPR 16, CISPR 18 (RF measurement and interference)
- IEC 60050‑161 (EMC vocabulary)
Keywords: electromagnetic fields, power transformers, EMC, radiated emission, conducted emission, power-frequency magnetic field, EN 60076, immunity.
Frequently Asked Questions
CLC/TR 50453:2007 is a technical report published by CLC. Its full title is "Evaluation of electromagnetic fields around power transformers". This standard covers: This Report provides guidance for the evaluation of electromagnetic fields around power transformers. This Report applies to power transformers covered by EN 60076 series with the following characteristics: - apparent rating P: 5 kVA P 1 000 MVA - insulating level, according to EN 60076-3: • high voltage winding: Um from 7,2 kV to 525 kV • low voltage winding: Um up to 525 kV Reactors are excluded from the present Report. Continuous conducted and radiated emissions are considered for power transformers operating under nominal working conditions of voltage and current. Fault conditions and low occurrence transient events, such as - short-circuits, - lightning and switching transients, - overloads (inrush currents, etc.), - overvoltages, - tap-changer operations, are not considered as normal working conditions. Immunity conditions are considered to ensure the power transformer operates as intended in its normal working environment. The immunity capability of the power transformer is considered for steady state and transient working conditions.
This Report provides guidance for the evaluation of electromagnetic fields around power transformers. This Report applies to power transformers covered by EN 60076 series with the following characteristics: - apparent rating P: 5 kVA P 1 000 MVA - insulating level, according to EN 60076-3: • high voltage winding: Um from 7,2 kV to 525 kV • low voltage winding: Um up to 525 kV Reactors are excluded from the present Report. Continuous conducted and radiated emissions are considered for power transformers operating under nominal working conditions of voltage and current. Fault conditions and low occurrence transient events, such as - short-circuits, - lightning and switching transients, - overloads (inrush currents, etc.), - overvoltages, - tap-changer operations, are not considered as normal working conditions. Immunity conditions are considered to ensure the power transformer operates as intended in its normal working environment. The immunity capability of the power transformer is considered for steady state and transient working conditions.
CLC/TR 50453:2007 is classified under the following ICS (International Classification for Standards) categories: 29.020 - Electrical engineering in general; 29.180 - Transformers. Reactors. The ICS classification helps identify the subject area and facilitates finding related standards.
CLC/TR 50453:2007 is associated with the following European legislation: Standardization Mandates: BC-01-87. When a standard is cited in the Official Journal of the European Union, products manufactured in conformity with it benefit from a presumption of conformity with the essential requirements of the corresponding EU directive or regulation.
You can purchase CLC/TR 50453:2007 directly from iTeh Standards. The document is available in PDF format and is delivered instantly after payment. Add the standard to your cart and complete the secure checkout process. iTeh Standards is an authorized distributor of CLC standards.
Standards Content (Sample)
SLOVENSKI STANDARD
01-september-2007
1DGRPHãþD
SIST R014-001:2001
Ocenitev elektromagnetnih polj okoli elektroenergetskih transformatorjev
Evaluation of electromagnetic fields around power transformers
Bewertung von elektromagnetischen Feldern in der Umgebung von
Leistungstransformatoren
Evaluation des champs électromagnétiques autour des transformateurs de puissance
Ta slovenski standard je istoveten z: CLC/TR 50453:2007
ICS:
29.180 Transformatorji. Dušilke Transformers. Reactors
33.100.01 Elektromagnetna združljivost Electromagnetic compatibility
na splošno in general
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.
TECHNICAL REPORT
CLC/TR 50453
RAPPORT TECHNIQUE
May 2007
TECHNISCHER BERICHT
ICS 29.020; 29.180 Supersedes R014-001:1999
English version
Evaluation of electromagnetic fields
around power transformers
Evaluation Bewertung
des champs électromagnétiques von elektromagnetischen Feldern
autour des transformateurs de puissance in der Umgebung
von Leistungstransformatoren
This Technical Report was approved by CENELEC on 2006-01-14.
CENELEC members are the national electrotechnical committees of Austria, Belgium, Bulgaria, Cyprus, the
Czech Republic, Denmark, Estonia, Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia,
Lithuania, Luxembourg, Malta, the Netherlands, Norway, Poland, Portugal, Romania, Slovakia, Slovenia, Spain,
Sweden, Switzerland and the United Kingdom.
CENELEC
European Committee for Electrotechnical Standardization
Comité Européen de Normalisation Electrotechnique
Europäisches Komitee für Elektrotechnische Normung
Central Secretariat: rue de Stassart 35, B - 1050 Brussels
© 2007 CENELEC - All rights of exploitation in any form and by any means reserved worldwide for CENELEC members.
Ref. No. CLC/TR 50453:2007 E
Foreword
This Technical Report was prepared by Technical Committee CENELEC TC 14, Power Transformers.
The text of the draft was circulated for vote in accordance with the Internal Regulations, Part 2,
Subclause 11.4.3.3 and was approved by CENELEC as CLC/TR 50453 on 2006-01-14.
This Technical Report supersedes R014-001:1999.
_______________
- 3 - CLC/TR 50453:2007
Contents
page
Introduction 4
1 Scope. 5
2 References. 5
3 Definitions. 5
4 Emission. 6
4.1 Radiated emission. 6
4.2 Conducted emission. 6
5 Immunity. 7
5.1 Radiated disturbances. 7
5.2 Conducted disturbances. 7
Annex A (informative) Method of calculation of power frequency magnetic field. 8
Annex B (informative) Method of calculation of power frequency electric field. 11
Bibliography. 13
Introduction
EMC is covered by three kinds of standardisation documents:
• Basic Standards:
Basic Standards are mainly informative documents covering disturbance phenomena, disturbance
levels and test and measurement techniques. For example, EN 61000/IEC 61000 is a Basic Standard.
• Generic Standards:
Generic Standards are intended to cover a range of products for which no Product Standard exists. For
example, EN 61000-3 and EN 61000-4, EN 61000-1 and EN 61000-2 are Generic Standards.
• Product Standards:
Product Standards are intended to deal with a specific family of electrical or electronic equipment.
Power transformers however, are considered as passive equipment and as such, the above referenced
documents are not applicable.
This Technical Report is intended to give guidance on EMC phenomena associated with power
transformers.
- 5 - CLC/TR 50453:2007
1 Scope
This Report provides guidance for the evaluation of electromagnetic fields around power transformers.
This Report applies to power transformers covered by EN 60076 series with the following characteristics:
- apparent rating P: 5 kVA ≤ P ≤ 1 000 MVA
- insulating level, according to EN 60076-3:
• high voltage winding: U from 7,2 kV to 525 kV
m
• low voltage winding: U up to 525 kV
m
Reactors are excluded from the present Report.
Continuous conducted and radiated emissions are considered for power transformers operating under
nominal working conditions of voltage and current.
Fault conditions and low occurrence transient events, such as
- short-circuits,
- lightning and switching transients,
- overloads (inrush currents, etc.),
- overvoltages,
- tap-changer operations,
are not considered as normal working conditions.
Immunity conditions are considered to ensure the power transformer operates as intended in its normal
working environment. The immunity capability of the power transformer is considered for steady state and
transient working conditions.
2 References
The following referenced documents are indispensable for the application of this document. For dated
references, only the edition cited applies. For undated references, the latest edition of the referenced
document (including any amendments) applies.
EN 60076 series Power transformers (IEC 60076 series)
EN 61000 series Electromagnetic compatibility (IEC 61000 series)
IEC 60050-161 1990 International Electrotechnical Vocabulary
Chapter 161: Electromagnetic Compatibility
3 Definitions
The definitions quoted in IEC 60050-161, in EN 60076 series as well as those mentioned in the above
referenced standards apply.
4 Emission
4.1 Radiated emission
4.1.1 Power frequency magnetic field
The most significant value of the power frequency magnetic field is due to the current flowing in the LV
terminals. The magnetic field of the transformer, produced by the currents flowing in the windings, can be
neglected.
The power frequency magnetic field radiated by a transformer without enclosure along its lateral faces has
the same order of magnitude as the field radiated by the currents flowing in the LV terminals.
The effect of this field can be reduced by providing a suitable enclosure or shielding.
As a guide, magnetic fields from simple busbar arrangements can be calculated to provide approximate
values for the transformer environment, as illustrated in Annex A.
4.1.2 Power frequency electric field
The electric field is produced by the energized conductors. The magnitude of the electric field in space is
proportional to the voltage level and is highly dependent on the position and shape of the other conducting
objects (energized or grounded) in the close environment.
Except for some special dry type transformers without an enclosure, the electric radiated fie
...
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