EN 50336:2002

SLOVENSKI SIST EN 50336:2004
STANDARD
september 2004
Bushings for transformers and reactor cable boxes not exceeding 36 kV
ICS 29.080.20; 29.180 Referenčna številka
©  Standard je založil in izdal Slovenski inštitut za standardizacijo. Razmnoževanje ali kopiranje celote ali delov tega dokumenta ni dovoljeno

EUROPEAN STANDARD EN 50336
NORME EUROPÉENNE
EUROPÄISCHE NORM June 2002
ICS 29.080.20; 29.180
English version
Bushings for transformers and reactor cable boxes
not exceeding 36 kV
Traversées pour boîtes à câbles Durchführungen für Kabelanschluss-
de transformateurs et d'inductances kästen von Transformatoren und
ne dépassant pas 36 kV Drosselspulen bis 36 kV
This European Standard was approved by CENELEC on 2001-12-04. CENELEC members are bound to
comply with the CEN/CENELEC Internal Regulations which stipulate the conditions for giving this
European Standard the status of a national standard without any alteration.
Up-to-date lists and bibliographical references concerning such national standards may be obtained on
application to the Central Secretariat or to any CENELEC member.
This European Standard exists in three official versions (English, French, German). A version in any
other language made by translation under the responsibility of a CENELEC member into its own
language and notified to the Central Secretariat has the same status as the official versions.
CENELEC members are the national electrotechnical committees of Austria, Belgium, Czech Republic,
Denmark, Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Luxembourg, Malta,
Netherlands, Norway, Portugal, Slovakia, Spain, Sweden, Switzerland and 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
© 2002 CENELEC - All rights of exploitation in any form and by any means reserved worldwide for CENELEC members.
Ref. No. EN 50336:2002 E
Foreword
This European Standard was prepared by the Technical Committee CENELEC TC 36A, Insulated bushings.
The text of the draft was submitted to the formal vote and was approved by CENELEC as EN 50336 on
2001-12-04.
The following dates were fixed:
- latest date by which the EN has to be implemented
at national level by publication of an identical
national standard or by endorsement (dop) 2002-12-01
- latest date by which the national standards conflicting
with the EN have to be withdrawn (dow) 2004-12-01
__________
- 3 - EN 50336:2002
Contents
Page
1 Scope . 4
2 Normative references . 4
3 Definitions. 4
4 Requirements . 5
4.1 Rating. 5
4.1.1 Standard values of rated voltage (U ). 5
r
4.1.2 Standard values of rated current (I ). 5
r
4.2 Compliance . 5
4.2.1 General - Ceramic bushings . 5
4.2.2 General - Resin insulated bushings. 6

1 Scope
This standard is applicable to insulated bushings for use in air insulated, shroud insulated and fully
insulated cable boxes for liquid filled transformers and reactors for rated voltages up to 36 kV, and rated
currents up to 4 000 A at frequencies from 15 Hz to 60 Hz.
2 Normative references
This European Standard incorporates, by dated or undated reference, provisions from other publications.
These normative references are cited at the appropriate places in the text and the publications are listed
hereafter. For dated references, subsequent amendments to or revisions of any of these publications
apply to this European Standard only when incorporated in it by amendment or revision. For undated
references, the latest edition of the publication referred to applies (including amendments).
EN 60137 1996 Insulated bushings for alternating voltages above 1 kV (IEC 60137:1995)
EN 61099 1992 Specification for unused synthetic organic esters for electrical purposes
(IEC 61099:1992)
EN 22768-1 1993 General tolerances - Part 1: Tolerances for linear and angular dimensions
without individual tolerance indications
HD 329 S1 1977 Tests on hollow insulators for use in electrical equipment (IEC 60233:1974)
HD 428.2.1 S1 1994 Three phase oil-immersed distribution transformers 50 Hz, from 50 kVA to
2,5 MVA with highest voltage for equipment not exceeding 36 kV -
Part 2: Distribution transformers with cable boxes on the high-voltage and/or
low-voltage side - Section 1: General requirements
HD 565 S1 1993 Specifications for silicone liquids for electrical purposes (IEC 60836:1988)
IEC 60296 1992 Specification for unused mineral insulating oils for transformers and switchgear
3 Definitions
For the purposes of this standard the following definitions apply:
3.1
air insulated cable box
a metallic cable box designed to protect the ends of the cables and bushings, providing a weatherproof
enclosure with a minimum rating of IP54. An air filled cable box within which the cable cores are
electrically terminated by stress control appropriate to the cable design and voltage; air being the sole
insulation for the terminal connections
3.2
shroud insulated cable box
an air filled cable box as in 3.1 but within which the cable cores are terminated with local insulation
enhancement, e.g. phase barrier, bushing protection or taping
3.3
fully insulated cable box
a cable box where those parts of the termination and bushing within the enclosure including live metal
parts and cable cores are insulated by liquid or compound suitable for the appropriate system voltage.
The box shall be suitably sealed to contain the liquid or compound and allow for their expansion due to
temperature changes
- 5 - EN 50336:2002
3.4
ceramic, glass or analogous inorganic material bushing
bushing in which the major insulation consists of a ceramic, glass or analogous inorganic material
3.5
cast or moulded resin insulated bushing
bushing in which the major insulation consists of a cast or moulded organic material with or without an
inorganic filler.
4 Requirements
Bushings covered by this specification are suitable for operation with one end fully immersed in an
insulating liquid and the other end either fully immersed in an insulating liquid; or with shrouded
insulation in air; or in air but not exposed to external atmospheric conditions.
All other requirements shall be as specified herein.
4.1 Rating
4.1.1 Standard values of rated voltage (U )
r
The value of U of a bushing shall be chosen from the standard values of the highest voltage for
r
transformers and reactors U given below in kilovolts:
m
12 - 24 - 36
NOTE 1  For ceramic bushings
where U is 1,1 then U 12 is to be used
m r
where U is 3,6 then U 12 is to be used
m r
where Um is 7,2 then Ur 12 is to be used
where U is 17,5 then U 24 is to be used.
m r
NOTE 2  For resin insulated bushings the permitted highest rated voltages U are
r
Liquid / air or air / air 1,1
Liquid / liquid 12.
4.1.2 Standard values of rated current (I )
r
The value I of a bushing shall be chosen from the standard values given below in amperes:
r
250 - 400 - 630 - 800 - 1 250 - 1 600 - 2 000 - 2 500 - 3 150 - 4 000
4.2 Compliance
4.2.1 General - Ceramic bushings
Ceramic bushings shall meet the requirements for both type and routine tests laid out in EN 60137 and in
addition the following shall also apply:
Bushings shall be capable of sealing a liquid filled chamber. The design of 24 kV and 36 kV bushings
shall be such that free entry of liquid is allowed into the space between the conductor and the ceramic. In
such instances the sealing integrity of the bushing shall be maintained.
The conductor size, material and nut and thread dimensions of the bushing terminal for the appropriate
current rating shall comply wit
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