IEC 60076-1:2011 pdf Power transformers – Part 1: General

IEC 60076-1:2011 pdf Power transformers – Part 1: General
1 Scope
This part of IEC 60076 applies to three-phase and single-phase power transformers (including
auto-transformers) with the exception of certain categories of small and special transformers
such as:
– single-phase transformers with rated power less than 1 kVA and three-phase transformers
less than 5 kVA;
– transformers, which have no windings with rated voltage higher than 1 000 V;
– instrument transformers;
– traction transformers mounted on rolling stock;
– starting transformers;
– testing transformers;
– welding transformers;
– explosion-proof and mining transformers;
– transformers for deep water (submerged) applications.
When IEC standards do not exist for such categories of transformers (in particular transformer
having no winding exceeding 1 000 V for industrial applications), this part of IEC 60076 may
still be applicable either as a whole or in part.
This standard does not address the requirements that would make a transformer suitable for
mounting in a position accessible to the general public.
For those categories of power transformers and reactors which have their own IEC standards,
this part is applicable only to the extent in which it is specifically called up by cross-reference
in the other standard. Such standards exist for:
– reactors in general (IEC 60076-6);
– dry-type transformers (IEC 60076-1 1 );
– self-protected transformers (IEC 60076-1 3);
– gas-filled power transformers (IEC 60076-1 5);
– transformers for wind turbine applications (IEC 60076-1 6);
– traction transformers and traction reactors (IEC 6031 0);
– converter transformers for industrial applications (IEC 61 378-1 );
– converter transformers for HVDC applications (IEC 61 378-2).
At several places in this part it is specified or recommended that an ‘agreement’ should be
reached concerning alternative or additional technical solutions or procedures. Such
agreement is made between the manufacturer and the purchaser. The matters should
preferably be raised at an early stage and the agreements included in the contract
specification.
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.
IEC 60076-2, Power transformers – Part 2: Temperature rise for liquid-immersed transformers
IEC 60076-3:2000, Power transformers – Part 3: Insulation levels, dielectric tests and external
clearances in air
IEC 60076-5:2006, Power transformers – Part 5: Ability to withstand short circuit
IEC 60076-1 0:2001 , Power transformers – Part 10: Determination of sound levels
IEC 60076-1 1 :2004, Power transformers – Part 11: Dry-type transformers
IEC 601 37:2008, Insulated bushings for alternating voltages above 1 000 V
IEC 6021 4-1 :2003, Tap-changers – Part 1: Performance requirements and test methods
IEC 60296:2003, Fluids for electrotechnical applications – Unused mineral insulating oils for
transformers and switchgear
IEC 60721 -3-4:1 995, Classification of environmental conditions – Part 3: Classification of
groups of environmental parameters and their severities – Section 4: Stationary use at non-
weatherprotected locations
ISO 9001 :2008, Quality management systems – Requirements
3 Terms and definitions
For the purposes of this document, the following terms and definitions apply.
NOTE Other terms use the meanings ascribed to them in the International Electrotechnical Vocabulary (IEV).
3.1 General
3.1.1 power transformer
a static piece of apparatus with two or more windings which, by electromagnetic induction,
transforms a system of alternating voltage and current into another system of voltage and
current usually of different values and at the same frequency for the purpose of transmitting
electrical power
[IEC 60050-421 :1 990, 421 -01 -01 , modified]
3.1.2 auto-transformer
a transformer in which at least two windings have a common part
[IEC 60050-421 :1 990, 421 -01 -1 1 ]
NOTE Where there is a need to express that a transformer is not auto-connected, use is made of terms such as separate winding transformer, or double-wound transformer (see IEC 60050-421 :1 990, 421 -01 -1 3).
3.1.3 series transformer
a transformer, other than an autotransformer, of which one winding is intended to be
connected in series with a circuit in order to alter its voltage and/or shift its phase. The other
winding is an energizing winding
[IEC 60050-421 :1 990, 421 -01 -1 2, modified]
NOTE Series transformers were called booster transformers in earlier editions of this standard.
3.1.4 liquid-immersed type transformer
a transformer in which the magnetic circuit and windings are immersed in liquid
3.1.5 dry-type transformer
a transformer in which the magnetic circuit and windings are not immersed in an insulating
liquid [IEC 60050-421 :1 990, 421 -01 -1 6]