IEC 60599:1999/AMD1:2007

INTERNATIONAL IEC
STANDARD
CEI
NORME
INTERNATIONALE
AMENDMENT 1
AMENDEMENT 1
2007-04
Amendment 1
Mineral oil-impregnated electrical
equipment in service –
Guide to the interpretation of dissolved
and free gases analysis
Amendement 1
Matériels électriques imprégnés d’huile
minérale en service –
Guide pour l’interprétation de l’analyse
des gaz dissous et des gaz libres

Reference number
Numéro de référence
IEC/CEI 60599 Amend. 1:2007
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INTERNATIONAL IEC
STANDARD
CEI
NORME
INTERNATIONALE
AMENDEMENT 1
AMENDMENT 1
2007-04
Amendment 1
Mineral oil-impregnated electrical
equipment in service –
Guide to the interpretation of dissolved
and free gases analysis
Amendement 1
Matériels électriques imprégnés d’huile
minérale en service –
Guide pour l’interprétation de l’analyse
des gaz dissous et des gaz libres

PRICE CODE
D
CODE PRIX
Commission Electrotechnique Internationale
International Electrotechnical Commission
МеждународнаяЭлектротехническаяКомиссия
For price, see current catalogue
Pour prix, voir catalogue en vigueur

– 2 – 60599 Amend. 1 © IEC:2007

FOREWORD
This amendment has been prepared by IEC technical committee 10:Fluids for electrotechnical

applications.
The text of this amendment is based on the following documents:

FDIS Report on voting
10/685/FDIS 10/693/RVD
Full information on the voting for the approval of this amendment can be found in the report
on voting indicated in the above table.
The committee has decided that the contents of this amendment and the base publication will
remain unchanged until the maintenance result date indicated on the IEC web site under
"http://webstore.iec.ch" in the data related to the specific publication. At this date, the
publication will be:
• reconfirmed,
• withdrawn,
• replaced by a revised edition, or
• amended.
___________
Page 43
Annex A – Equipment application notes
Replace the existing text of these notes with the following new text:
WARNING: “Limit values” of gas concentrations and rates of gas increase in service are not
the responsibility of TC10 but of IEC equipment committees.
“Typical values” in the following application notes are not limit values. They are given for
information only, as a maintenance tool. In a given transformer population, they indicate for
example that 90 % of DGA values in service are below the 90 % typical values and 10 % are
above. When typical values are exceeded, the only action recommended in this standard is to
increase the frequency of DGA analyses.
Typical values depend on several parameters (age, type and manufacturer of equipment,
operating and loading practices, climate, etc.), and are not exactly the same for all electrical
networks. Ranges of typical values are therefore indicated in the following application notes,
covering the different individual values observed worldwide and surveyed by IEC and CIGRE.

60599 Amend. 1 © IEC:2007 – 3 –

Individual networks are strongly encouraged to calculate the typical values corresponding to
their own specific transformer population, using DGA data meeting IEC 60567 specifications

for accuracy and following methods indicated in Clause 8 and in CIGRE Brochure # 296

(2006).
The ranges of typical values indicated in these application notes should be used only by

default, when individual values are not available, and should not be used in a contract without

a special agreement between the user and manufacturer of the equipment.

A.1 Power transformers
Delete the text of the paragraph under the title.

Page 47
Subclauses A.1.4 and A.1.5
Replace the text of these subclauses with the following new text:
A.1.4 Typical concentration values
Important note: the “WARNING” clause at the beginning of Annex A shall be consulted
before using A.1.4.
Ranges of 90 % typical gas concentration values observed in power transformers, from about
25 electrical networks worldwide and including more than 20 000 transformers, are given in
Table A.2. For hydrogen for example, one network reported a typical value of 50 μl/l, another
one 150 μl/l and the 23 others reported values between 50 μl/l and 150 μl/l. These ranges of
values have been reported by CIGRE SC D1 and A2 (TF11) and approved by IEC TC 10 and
TC 14.
Table A.2 – Ranges of 90 % typical gas concentration values
observed in power transformers, in μl/l
C H H CH C H C H CO CO
2 2 2 4 2 4 2 6 2
All transformers 50 - 150 30 - 130 60 - 280 20 - 90 400 - 600 3 800 -
14 000
No OLTC 2 - 20
Communicating OLTC 60 - 280
“Communicating OLTC” in Tables A.2 and A.3 means that some oil and/or gas communication
is possible between the OLTC compartment and the main tank or between the respective
conservators. These gases may contaminate the oil in the main tank and affect concentration
values in these types of equipment. “No OLTC” refers to transformers not equipped with an
OLTC, or equipped with a tap changer not communicating with or leaking to the main tank.

– 4 – 60599 Amend. 1 © IEC:2007

Typical values in Table A.2 apply to both breathing and sealed transformers, and correspond
mostly to core-type transformers. Values in shell-type transformers are likely to be higher. In

two countries, values for C H are higher. In one country where transformers are operated

2 6
below nominal load, values for CH and CO and particularly for C H are lower. In one

4 2 4
co
...