CLC/TS 50458:2006

SLOVENSKI STANDARD
01-oktober-2006
Skoznjik za zunanjo montažo s porazdeljeno kapacitivnostjo za napetosti od 52 kV
do 420 kV za transformatorje, potopljene v olje
Capacitance graded outdoor bushing 52 kV up to 420 kV for oil immersed transformers
Kapazitiv gesteuerte Freiluftdurchführungen 52 kV bis 420 kV für ölgefüllte
Transformatoren
Traversées à répartition capacitive immergées d'extérieur, 52 kV à 420 kV pour
transformateurs immergés dans l'huile
Ta slovenski standard je istoveten z: CLC/TS 50458:2006
ICS:
29.080.20 Skoznjiki Bushings
29.180 Transformatorji. Dušilke Transformers. Reactors
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

TECHNICAL SPECIFICATION
CLC/TS 50458
SPÉCIFICATION TECHNIQUE
April 2006
TECHNISCHE SPEZIFIKATION
ICS 29.080.20
English version
Capacitance graded outdoor bushing 52 kV up to 420 kV
for oil immersed transformers
Traversées à répartition capacitive Kapazitiv gesteuerte
immergées d'extérieur, 52 kV à 420 kV Freiluftdurchführungen 52 kV bis 420 kV
pour transformateurs für ölgefüllte Transformatoren
immergés dans l'huile
This Technical Specification was approved by CENELEC on 2005-10-15.

CENELEC members are required to announce the existence of this TS in the same way as for an EN and to
make the TS available promptly at national level in an appropriate form. It is permissible to keep conflicting
national standards in force.
CENELEC members are the national electrotechnical committees of Austria, Belgium, 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

© 2006 CENELEC - All rights of exploitation in any form and by any means reserved worldwide for CENELEC members.
Ref. No. CLC/TS 50458:2006 E
Foreword
This Technical Specification was prepared by the Technical Committee CENELEC TC 36A, Insulated
bushings.
The text of the draft was submitted to vote in accordance with Subclause 11.3.3.3 of Part 2 of the CENELEC
Internal Regulations and was approved by CENELEC as CLC/TS 50458 on 2005-10-15.
The following date was fixed:
– latest date by which the existence of the CLC/TS
has to be announced at national level (doa) 2006-07-01
The purpose of this Technical Specification is to ensure the interchange ability between capacitance graded
bushings, with comparable technical requirements, from different manufacturers.
The aim is, to reduce the multiplicity of the different designs, only regarding the interchange ability. The
document gives recommendations for mounting flange dimensions, lower part details, current conductor
connections and limits for the overall dimensions. This allows, on the one hand, the manufacturers of
bushings to use normalised solutions within their own type series and on the other, the users to exchange
bushings from different manufacturers and with different years of manufacture.
In the preparation of this Technical Specification information about existing types (especially details of the
design and the dimensions taken mostly from catalogues of the European manufacturers) was the basis for
discussion in WG 4 of TC 36A. The following restrictions were applied:
• technical aspects of the design of different manufacturers and the requirements of users must be
considered for the values of the new Technical Specification regarding the state of art;
• there should be no single effort for one manufacturer or to the exclusion of another;
• no restriction for the technical evolution.
Conformance will require design changes for not only the manufacturer of the bushings but also
transformers. Some changes may require significant modifications along with type tests which are time
consuming and costly. Purchasers of transformers should also review its contents for its impact on their
procurement process. For these reasons, this document will act as a guide or Technical Specification (TS)
during a transitional period. During this period, the contents will act as a guide to manufacturers while
allowing debate in the industry on its effectiveness and value. This transition period will not exceed ten years
at which time its contents should be amended if necessary and submitted for approval as a European
Standard.
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Contents
Page
Introduction 4
1 Scope 4
2 Normative references 4
3 Definitions 4
3.1 Draw-lead conductor 4
3.2 Solid rod conductor 4
3.3 Bottom terminal - current connection 5
4 Requirements 5
4.1 Application 5
4.2 Standard values of highest voltage for equipment (U ) 5
m
4.3 Standard values of rated current (I ) 5
r
4.4 Compliance 5
4.4.1 Test tap 5
4.4.2 Creepage distance 5
4.4.3 Insulating level 5
4.4.4 Operating conditions, test requirements 5
4.5 Additional requirements 5
4.6 Designation 6
4.6.1 Electrical design of oil end 6
4.6.2 Conductor principles and mechanical design of oil end 6
4.6.3 Conductor arrangement 6
4.6.4 Complete bushing designation 7
4.7 Design details 8
Annex A (informative)  Example of bushing documentation 17
Figure 1 – Bushing dimensions (general) 8
Figure 2 – Bushing oil end dimensions 9
Figure 3 – Examples of current leader principles and mechanical design of oil end 10
Figure 4 – Jointing of split rod conductor 15
Figure 5 – Example of bottom connection 16

Table 1 – Dimensions of air terminal stems according to IEC/TR 62271-301 8
Table 2 – Dimensions 11
Table 3 – Two examples of data for split rod type inside the bore 15

Introduction
The object of this Technical Specification is to specify details and dimensions of capacitance graded outdoor
bushings for highest voltages for equipment from 52 kV up to 420 kV as far as it is necessary to ensure the
interchange ability of bushings with comparable technical requirements. Additionally, some technical items
are site specific, and are rarely able to be standardised, e.g. airside length of a bushing which depends on
the different air side material, shed profiles and pollution level. This Technical Specification defines additional
data or information, which must be included, by the bushing or the transformer manufacturer, in the
transformer manual for the purpose of interchange ability.
1 Scope
This Technical Specification is applicable to capacitance graded outdoor bushings with values of highest
voltage for equipment (U ) from 52 kV up to 420 kV and with values of rated current (I ) up to 3 150 A and
m r
frequencies from 15 Hz up to 60 Hz for oil immersed transformers.
The major insulation of these bushings consists either of oil-impregnated or resin-impregnated paper or other
suitable insulating systems.
This Technical Specification establishes essential details and dimensions to ensure interchange ability and
adequate mounting of the bushings.
2 Normative 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 60059 1999 IEC standard currents (IEC 60059:1999)
EN 60076-3 2001 Power transformers – Part 3: Insulation levels and dielectric tests and
external clearances in air (IEC 60076-3:2000 + corrigendum Dec. 2000)
EN 60137 2003 Insulated bushings for alternating voltages above 1 000 V (IEC 60137:2003)
EN 60296 Specification for unused mineral oil for transformers and switchgear
(IEC 60296)
IEC 60038 1983 IEC standard voltages
IEC 60815 1986 Guide for the selection of insulators in respect of polluted conditions
IEC/TR 62271-301 2004 High-voltage switchgear and controlgear – Part 301: Dimensional
standardization of terminals
3 Definitions
For the definitions of generally used terms in the present Technical Specification reference should be made
to EN 60137.
For the purposes of this Technical Specification the following additional definitions apply:
3.1
draw-lead conductor
conductor consisting of one or more flexible leads in parallel drawn into the central tube of the major
insulation body of the bushing (preferred up to 1 000 A)
3.2
solid rod or tube conductor
conductor consisting of a round rod either removable and drawn into the central tube of the major insulation
body of the bushing or fixed rod or tube and not removable (preferred from 1 250 A up to 3 150 A)

- 5 - CLC/TS 50458:2006
3.3
bottom terminal – current connection
a device used to terminate the leads from the transformer at a position below and adjacent to the lower end
of the bushing
The terminal may be removable or non-removable according to the following:
• removable bottom connections may be either attached to the lower end of the bushing or guided into
position by a draw-rod through the center bore of the bushing and locked in position on the air side of the
bushing. The draw-rod may also be pre-stressed to achieve a clamping force on the removable bottom
connection. The draw-rod with these functions is not part of the current conducting path within the
bushing.
• non-removable bottom connections usually consist of a terminal that is permanently attached to the
lower end of the bushing.
NOTE 1 Where the solid rod conductor is drawn into the bushing the conductor should be split as shown in Figure 4.
NOTE 2 The rated currents corresponding to a cross section of the current conductors may differ for oil-impregnated or
resin-impregnated paper bodies due to the different insulating materials and the geometrical bushing data.
NOTE 3 Due to handling problems solid rod conductors with masses above 30 kg should preferably be fixed and
bottom connected (see 4.6.3).
4 Requirements
4.1 Application
The bushings covered by this Technical Specification shall be capacitance graded outdoor bushings suitable
for operations with one end in air and the other end fully immersed in transformer oil according to EN 60296
or similar fluids.
4.2 Standard values of highest voltage for equipment (U )
m
The value of U of a bushing shall be chosen from the standard values (defined in IEC 60038), as given
m
below, in kilovolts (kV):
52 - 72,5 - 100 - 123 - 145 - 170 - 245 - 300 - 420
4.3 Standard values of rated current (I )
r
The value of I of a bushing shall be chosen from the standard values (defined in EN 60059), as given below,
r
in amperes (A):
630 - 800 – 1 000 - 1 250 - 1 600 - 2 000 - 2 500 - 3 150
NOTE Where the required bushing current rating does not appear in Table 2, the next higher value of standard current
rating shall be used.
4.4 Compliance
The bushings according to this Technical Specification shall meet the requirements of EN 60137.
4.4.1 Test tap
Each bushing covered by this Technical Specification must have a test tap as defined in EN 60137.
4.4.2 Creepage distance
The required creepage distance of a bushing depends on the value of the pollution level, the reference
minimum nominal specific creepage distance (EN 60137, IEC 60815) and the highest voltage for equipment
U .
m
4.4.3 Insulating level
The standard values of insulating levels are in accordance to EN 60076-3 and EN 60137 whichever is
higher.
4.4.4 Operating conditions, test requirements
Requirements and methods for operating conditions and tests are given in EN 60137 and EN 60076-3.
4.5 Additional requirements
Additional electrical requirements, e.g.
! external clearances between phases or to earth,
! special overload conditions, etc.
and mechanical requirements, e.g.
! mounting with inclination angle exceeding 30° from the vertical,
! earthing eye of the flange,
! venting plug of the current lead tube and the flange,
! ceramic or other material for the outside insulator,
! oil level gauge,
! earthquake strength, etc.
are not considered in this Technical Specification. They depend on several other standards and must be
defined in addition to this Technical Specification if necessary.
All dimensions described in Figures 1 up to 5 of this Technical Specification must, where relevant, be given
in the bushing manual (drawings and data sheets from the bushing manufacturer). This bushing manual
must be included in the transformer instruction manual. The information in the transformer instruction manual
must give sufficient information for the interchange ability.
4.6 Designation
The following designation by letters shall identify the main design details of the bushings according to this
Technical Specification.
4.6.1 Electrical design of oil end
M = oil end without shield (no special oil end)
N = oil end with embedded shield
O = oil end with attached shield (Shield may be removable, or an integrated non-removable part of the
bushing; shield length is not included in L5. Dimensional and
constructional details of the shield shall be stated in the bushing
manual.)
4.6.2 Conductor principles and mechanical design of oil end
P = removable conductor, bushing opening continuous cylindrical
Q = removable conductor, bushing opening conical
R = removable conductor, bushing opening stepped cylindrical or cylindrical / conical
T = fixed rod or tube
4.6.3 Conductor arrangement
U = draw-lead conductor without split rod (soldered into the air side connecting bolt)
1)
V = conductor with split inside the bushing tube
2)
W = rod or tube end for removable bottom connection
3)
X = rod or tube end for non-removable bottom connection

1)
Dimensions of split rod conductor according to Figure 4.
2)
Figure 5 is only an example for required dimensions. The Figure shows a typical arrangement for an oil end terminal palm to be
attached to the lower end of the bushing.
3)
A non-removable bottom connectio
...