EN 60814:1997
(Main)Insulating liquids - Oil-impregnated paper and pressboard - Determination of water by automatic coulometric Karl Fischer titration
Insulating liquids - Oil-impregnated paper and pressboard - Determination of water by automatic coulometric Karl Fischer titration
Describes methods for the determination of water in insulating liquids and in oil-impregnated cellulosic insulation with coulmetrically generated Karl Fischer reagent.
Isolierflüssigkeiten - Ölimprägniertes Papier und ölimprägnierter Presspan - Bestimmung von Wasser durch automatische coulometrische Karl-Fischer-Titration
Isolants liquides - Cartons et papiers imprégnés d'huile - Détermination de la teneur en eau par titrage coulométrique de Karl Fischer automatique
Décrit des méthodes de détermination de la teneur en eau des isolants liquides et des isolants cellulosiques imprégnés d'huile, par la méthode de titrage coulométrique de Karl Fischer.
Insulating liquids - Oil-impregnated paper and pressboard - Determination of water by automatic coulometric Karl Fischer titration (IEC 60814:1997)
General Information
Standards Content (Sample)
SLOVENSKI STANDARD
01-januar-1999
Insulating liquids - Oil-impregnated paper and pressboard - Determination of water
by automatic coulometric Karl Fischer titration (IEC 60814:1997)
Insulating liquids - Oil-impregnated paper and pressboard - Determination of water by
automatic coulometric Karl Fischer titration
Isolierflüssigkeiten - Ölimprägniertes Papier und ölimprägnierter Presspan - Bestimmung
von Wasser durch automatische coulometrische Karl-Fischer-Titration
Isolants liquides - Cartons et papiers imprégnés d'huile - Détermination de la teneur en
eau par titrage coulométrique de Karl Fischer automatique
Ta slovenski standard je istoveten z: EN 60814:1997
ICS:
29.040.10 Izolacijska olja Insulating oils
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.
NORME
CEI
INTERNATIONALE
IEC
INTERNATIONAL
Deuxième édition
STANDARD
Second edition
1997-08
Isolants liquides – Cartons et papiers
imprégnés d'huile –
Détermination de la teneur en eau par titrage
coulométrique de Karl Fischer automatique
Insulating liquids – Oil-impregnated paper
and pressboard –
Determination of water by automatic
coulometric Karl Fischer titration
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60814 © IEC:1997 – 3 –
CONTENTS
Page
FOREWORD . 5
Clause
1 General. 7
1.1 Scope. 7
1.2 Normative references.7
2 Direct titration for low viscosity liquids . 7
2.1 Field of application . 7
2.2 Chemistry. 9
2.3 Apparatus. 9
2.4 Reagents and auxiliary materials . 13
2.5 Preparation of the apparatus. 13
2.6 Sampling methods.13
2.7 Procedure. 15
2.8 Calculation of the result. 15
2.9 Report. 15
2.10 Precision. 17
3 Evaporative stripping method for high viscosity liquids . 17
3.1 Field of application . 17
3.2 Outline of the method. 17
3.3 Apparatus and reagents. 17
3.4 Procedure. 19
3.5 Calculation of water content. 19
3.6 Report. 19
4 Determination of water in oil-impregnated paper and pressboard . 21
4.1 Field of application . 21
4.2 Determination of water after previous extraction with methanol . 21
4.3 Determination by direct titration. 23
4.4 Evaporative stripping method. 25
Figures
1 Block diagram of automatic titrator. 29
2 Suitable titration vessel assembly . 31
3 Block diagram of automatic titrator and evaporation stripping unit . 33
4 Evaporator glass vessel with heater. 35
5 Methanol container and extraction tube . 37
Annex A – Method for sampling of oil-impregnated paper and pressboard . 39
60814 © IEC:1997 – 5 –
INTERNATIONAL ELECTROTECHNICAL COMMISSION
_________
INSULATING LIQUIDS – OIL-IMPREGNATED PAPER AND PRESSBOARD –
DETERMINATION OF WATER BY AUTOMATIC COULOMETRIC
KARL FISCHER TITRATION
FOREWORD
1) The IEC (International Electrotechnical Commission) is a worldwide organization for standardization comprising
all national electrotechnical committees (IEC National Committees). The object of the IEC is to promote
international co-operation on all questions concerning standardization in the electrical and electronic fields. To
this end and in addition to other activities, the IEC publishes International Standards. Their preparation is
entrusted to technical committees; any IEC National Committee interested in the subject dealt with may
participate in this preparatory work. International, governmental and non-governmental organizations liaising
with the IEC also participate in this preparation. The IEC collaborates closely with the International Organization
for Standardization (ISO) in accordance with conditions determined by agreement between the two organizations.
2) The formal decisions or agreements of the IEC on technical matters express, as nearly as possible, an
international consensus of opinion on the relevant subjects since each technical committee has representation
from all interested National Committees.
3) The documents produced have the form of recommendations for international use and are published in the form
of standards, technical reports or guides and they are accepted by the National Committees in that sense.
4) In order to promote international unification, IEC National Committees undertake to apply IEC International
Standards transparently to the maximum extent possible in their national and regional standards. Any
divergence between the IEC Standard and the corresponding national or regional standard shall be clearly
indicated in the latter.
5) The IEC provides no marking procedure to indicate its approval and cannot be rendered responsible for any
equipment declared to be in conformity with one of its standards.
6) Attention is drawn to the possibility that some of the elements of this International Standard may be the subject
of patent rights. The IEC shall not be held responsible for identifying any or all such patent rights.
International Standard IEC 60814 has been prepared by IEC technical committee 10: Fluids for
electrotechnical applications.
This second edition of IEC 60814 cancels and replaces the first edition published in 1985 of
which it constitutes a technical revision.
It also cancels IEC 60733, published in 1982.
The text of this standard is based on the following documents:
FDIS Report on voting
10/406/FDIS 10/422/RVD
Full information on the voting for the approval of this standard can be found in the report on
voting indicated in the above table.
Annex A is for information only.
60814 © IEC:1997 – 7 –
INSULATING LIQUIDS – OIL-IMPREGNATED PAPER AND PRESSBOARD –
DETERMINATION OF WATER BY AUTOMATIC COULOMETRIC
KARL FISCHER TITRATION
1 General
1.1 Scope
This International Standard describes methods for the determination of water in insulating
liquids and in oil-impregnated cellulosic insulation with coulometrically generated Karl Fischer
reagent.
The method in clause 2 is applicable to water concentrations above 2 mg/kg in liquids having
viscosity of less than 100 mm /s at 40 °C.
The test method in clause 3, where water is extracted by means of a nitrogen stream, is the
preferred method for insulating liquids of viscosity higher than 100 mm /s.
Clause 4 describes methods for the determination of water content in oil-impregnated paper
and pressboard over the range 0,1 % to 20 % by mass.
1.2 Normative references
The following normative documents contain provisions which, through reference in this text,
constitute provisions of this International Standard. At the time of publication, the editions
indicated were valid. All normative documents are subject to revision, and parties to
agreements based on this International Standard are encouraged to investigate the possibility
of applying the most recent editions of the normative documents indicated below. Members of
IEC and ISO maintain registers of currently valid International Standards.
IEC 60475: 1974, Method of sampling liquid dielectrics
IEC 60567: 1992, Guide for the sampling of gases and of oil from oil-filled electrical equipment
and for the analysis of free and dissolved gases
ISO 595-1: 1986, Reusable all-glass or metal-and-glass syringes for medical use – Part 1:
Dimensions
ISO 595-2: 1987, Reusable all-glass or metal-and-glass syringes for medical use – Part 2:
Design, performance requirements and tests
2 Direct titration for low viscosity liquids
2.1 Field of application
This method is applicable to water concentrations above 2 mg/kg in liquids having viscosity up
to 100 mm /s at 40 °C. The precision data given in 2.10 apply only to new liquids.
NOTES
1 For liquids in service, the accuracy of the method may be affected by the presence of contaminants and
degradation products.
2 The method has been designed to be particularly suitable to hydrocarbon and ester liquids. With other
liquids, particularly silicone fluids, methanol free reagents must be used.
60814 © IEC:1997 – 9 –
2.2 Chemistry
The reactions occurring in a Karl Fischer titration are known to be complex, but are essentially
of water with iodine, sulphur dioxide, an organic base and an alcohol in an organic solvent. The
original Karl Fischer reagent used pyridine and methanol, and the reactions may be expressed
as:
H O + I + SO + 3C H N → 2C H N.HI + C H N.SO (1)
2 2 2 5 5 5 5 5 5 3
C H N.SO + CH OH → C H NH.SO .CH (2)
5 5 3 3 5 5 4 3
Other base-alcohol combinations are possible and may be necessary for titrations on some
insulating liquids.
In coulometric Karl Fischer titration, the sample is mixed with a base/alcohol solution of iodide
ion and sulphur dioxide. Iodine is generated electrolytically and reacts with water in a similar
way to that shown in reactions (1) and (2). Iodine is generated in proportion to the quantity of
electricity according to Faraday's law, as shown by the following reaction:
-
2 I – 2 e → I (3)
One mole of iodine reacts with one mole of water stoichiometrically as shown in reactions (1)
so that 1 mg of water is equivalent to 10,72 C (number of coulombs). Based on this principle it
is possible to determine the amount of water directly from the quantity of electricity (number of
coulombs) required for the electrolysis.
2.3 Apparatus
2.3.1 Principle of operation
The titration vessel has the configuration of an electrolysis cell with two compartments
connected by a porous diaphragm. The anodic compartment contains the mixture of reagent-
solvent and sample (anodic solution), the cathodic compartment (generator assembly) contains
anhydrous reagent (cathodic solution). On both sides of the diaphragm are located the
electrolysis electrodes.
NOTE – Titrators without the porous diaphragm may be used.
Iodine generated by the electrolysis, as shown in reaction (3), reacts with the water in a similar
way to the Karl Fischer reactions (1) and (2). The end-point of the reaction is detected by a pair
of platinum electrodes immersed in the anodic solution. At the end of the titration, excess
iodine depolarizes the dual platinum electrodes, giving a change in the current/voltage ratio
which is used to activate the end-point indicator and to stop the current integrator.
The current integrator integrates the current consumed during the electrolysis, calculates the
water equivalent according to Faraday's law, and finally displays it in micrograms of water.
2.3.2 De
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