BS EN IEC 61125:2018 – TC:2020 Edition
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Tracked Changes. Insulating liquids. Test methods for oxidation stability. Test method for evaluating the oxidation stability of insulating liquids in the delivered state
| Published By | Publication Date | Number of Pages |
| BSI | 2020 | 86 |
IEC 61125:2018 describes a test method for evaluating the oxidation stability of insulating liquids in the delivered state under accelerated conditions regardless of whether or not antioxidant additives are present. The duration of the test can be different depending on the insulating liquid type and is defined in the corresponding standards (e.g. in IEC 60296, IEC 61099, IEC 62770). The method can be used for measuring the induction period, the test being continued until the volatile acidity significantly exceeds 0,10 mg KOH/g in the case of mineral oils. This value can be significantly higher in the case of ester liquids. Additional test methods such as those described in IEC TR 62036 based on differential scanning calorimetry can also be used as screening tests, but are out of the scope of this document. This second edition cancels and replaces the first edition published in 1992 and Amendment 1: 2004. This edition constitutes a technical revision. This edition includes the following significant technical changes with respect to the previous edition: a) the title has been modified to include insulating liquids different from mineral insulating oils (hydrocarbon); b) the method applies for insulating liquids in the delivered state; c) former Method C is now the main normative method; d) precision data of the main normative method has been updated concerning the dissipation factor; e) former Method A has been deleted; f) former Method B has been transferred to Annex B; g) a new method evaluating the thermo-oxidative behaviour of esters is included in Annex C.
PDF Catalog
| PDF Pages | PDF Title |
|---|---|
| 54 | undefined |
| 59 | English CONTENTS |
| 62 | FOREWORD |
| 64 | 1 Scope 2 Normative references |
| 65 | 3 Terms and definitions |
| 66 | 4 Apparatus 4.1 General principle of the method 4.2 Equipment 4.2.1 Heating arrangement |
| 67 | 4.2.2 Test vessels 4.2.3 Absorption tubes 4.2.4 Filtering crucibles |
| 68 | 4.2.5 Porcelain vessels 4.2.6 Flowmeter 4.2.7 Timer 4.2.8 Gas supply 4.2.9 Analytical balance 4.2.10 Burette 4.2.11 Volumetric pipette |
| 69 | 4.2.12 Volumetric flask 4.2.13 Graduated measuring cylinder 4.2.14 Thermometer 4.2.15 Erlenmeyer flask 4.3 Reagents 4.3.1 Normal heptane 4.3.2 Alkali blue 6B indicator according to IEC 62021-2 4.3.3 Phenolphthalein indicator 4.3.4 Potassium hydroxide according to IEC 62021-2 4.3.5 Oxidant gas 4.3.6 Acetone 4.4 Cleaning of test vessels |
| 70 | 4.5 Catalyst 4.6 Insulating liquid sample conditioning 4.7 Preparation of the test 4.8 Determinations on the oxidized insulating liquid 4.8.1 Sludge formation |
| 71 | 4.8.2 Soluble acidity (SA) 4.8.3 Volatile acidity (VA) |
| 72 | 4.8.4 Total acidity (TA) 4.8.5 Dielectric dissipation factor (DDF) 4.8.6 Oxidation rate with air 4.8.7 Induction period with air (IP with air) (optional) 4.9 Report |
| 73 | 4.10 Precision 4.10.1 General 4.10.2 Repeatability (r) (95 % confidence) 4.10.3 Reproducibility (R) (95 % confidence) Tables Table 1 – Repeatability and reproducibility of the oxidation stability test of uninhibited mineral oil in the delivered state for 164 h at 120 °C |
| 74 | Figures Figure 1 – Typical 8 hole (4 x 2) aluminium heating block Figure 2 – Aluminium alloy temperature measuring block |
| 75 | Figure 3 – Position of the tube in the oil bath Figure 4 – Oxidation tube or absorption tube |
| 76 | Figure 5 – Oxidation tube and absorption tube assembly |
| 77 | Annexes Annex A (normative) Thermometer specifications Table A.1 – Thermometer specifications |
| 78 | Annex B (informative) Method for evaluating the oxidation stability of inhibited insulating liquids in the delivery state by measurement of the induction period with oxygen B.1 Outline of the method B.2 Reagents and test conditions B.3 Procedure B.3.1 General B.3.2 Preparation of the test |
| 79 | B.3.3 Oxidation B.3.4 Determination of the induction period with oxygen B.3.5 Determinations on the oxidized oil (optional) |
| 80 | B.4 Report B.5 Precision B.5.1 General B.5.2 Relative repeatability (r) (95 % confidence) B.5.3 Relative reproducibility (R) (95 % confidence) Table B.1 – Precision data for induction time with oxygen for the oxidation testfor mineral oil according to Annex B |
| 81 | Annex C (informative) Method for evaluation of thermo-oxidative behaviour of unused ester insulating liquids C.1 Outline of the method C.2 Equipment C.2.1 Heating arrangement C.2.2 Test vessels C.2.3 Reagents C.3 Test procedure C.3.1 Sample conditioning and preparation |
| 82 | C.3.2 Ageing procedure C.4 Determination of the oxidized insulating liquid C.4.1 Soluble acidity C.4.2 Dielectric dissipation factor (DDF) at 90 C C.4.3 Appearance C.4.4 Kinematic viscosity C.5 Report Figure C.1 – Headspace vial with copper catalyst |
| 83 | C.6 Precision Table C.1 – Precision data for headspace procedure according to Annex C |
| 84 | Bibliography |
