IEC 60076-11-2018 pdf free download

IEC 60076-11-2018 pdf free download.Power transformers – Part 11: Dry-type transformers.
Where IEC standards do not exist for the transformers mentioned above or for other special transformers, this document may be applicable as a whole or in parts.
2 Normative references
The following documents are referred to in the text in such a way that some or all of their content constitutes requirements 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 60068-3-3, Environmental testing — Part 3-3: Guidance — Seismic test methods for equipments
IEC 60071-1, Insulation co-ordination — Part 1: Definitions, principles and rules
IEC 60071-2, Insulation co-ordination — Part 2: Application guidelines
IEC 60076-1:2011, Power transformers — Part 1: General
IEC 60076-2, Power transformers — Part 2: Temperature rise for liquid-immersed transformers
IEC 60076-3:2013, Power transformers — Part 3: Insulation levels, dielectric tests and external clearances in air
3 Terms and definitions
For the purposes of this document, the following terms and definitions apply.
ISO and IEC maintain terminological databases for use in standardization at the following addresses:
• IEC Electropedia: available at http://www.electropedia.org/
• ISO Online browsing platform: available at http://www.iso.org/obp
dry-type transformer
transformer of which the magnetic circuit and windings are not immersed in an insulating liquid
3.2 totally enclosed dry-type transformer
transformer in an un-pressurised enclosure cooled by the circulation of the internal air having no intentional exchange with external air
3.3 enclosed dry-type transformer
transformer in a ventilated enclosure cooled by the circulation of the external air
4 Service conditions
4.1 General
The requirements of IEC 60076-1 apply to dry-type transformers only in so far as they are referred to in this document.
4.2 Normal service conditions
a) Altitude:
See IEC 60076-1.
b) Temperature of cooling air and water:
See IEC 60076-1.
For water cooled transformers, specification of the water (temperature, water flow, etc.) has to be defined by agreement between manufacturer and purchaser if the temperature of the water is different from that specified In IEC 60076-1 and IEC 60076-2
NOTE Liquids other than water can be used as a cooling medium then all technical data of the liquid has to
be defined by agreement between manufacturer and purchaser
C) Wave-shape of supply voltage:
A sinusoidal supply voltage with a total harmonic content not exceeding 5 % and an even harmonic content not exceeding 1 %.
The purchaser shall specify the magnitude and frequency of any harmonic voltages present in the supply that exceed these limits.
The manufacturer should take into account these harmonics in determination of additional core losses and also regarding the saturation of the core.
d) Load current harmonic content:
At the enquiry stage the purchaser shall specify the magnitude and frequency of each of the harmonic current components generated by the load.
The manufacturer shall consider the additional losses caused by harmonic currents in calculating the temperature rise of the windings and the effects on the other metallic parts of the transformer.
The manufacturer shall calculate the additional loss by using the method of IEC 61378-1 or by using a method like finite element by agreement between manufacturer and purchaser.
If the total harmonic content of the load current exceeds 5 %, then the extra losses due to these harmonic currents shall be taken into account by increasing the test current for the temperature rise test. The temperature rise with these losses shall not exceed the corresponding limit specified in Table 2 when tested in accordance with 14.3.2.IEC 60076-11 pdf download.