BS EN IEC 61125:2018
$167.15
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 | 2018 | 34 |
This document 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.
The insulating liquid sample is maintained at 120 °C in the presence of a solid copper catalyst whilst bubbling air at a constant flow. The degree of oxidation stability is estimated by measurement of volatile acidity, soluble acidity, sludge, dielectric dissipation factor, or from the time to develop a given amount of volatile acidity (induction period with air).
In informative Annex B, a test method for evaluating the oxidation stability of inhibited mineral insulating oils in the delivered state by measurement of the induction period with oxygen is described. The method is only intended for quality control purposes. The results do not necessarily provide information on the performance in service. The oil sample is maintained at 120 °C in the presence of a solid copper catalyst whilst bubbling through a constant flow of oxygen. The degree of oxidation stability is estimated by the time taken by the oil to develop a determined amount of volatile acidity (induction period with oxygen). Additional criteria such as soluble and volatile acidities, sludge and dielectric dissipation factor can also be determined after a specified duration.
In informative Annex C, a test method intended to simulate the thermo-oxidative behaviour of ester insulating liquids (headspace of air at 150 °C for 164 h) is described.
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.
PDF Catalog
| PDF Pages | PDF Title |
|---|---|
| 2 | undefined |
| 7 | English CONTENTS |
| 10 | FOREWORD |
| 12 | 1 Scope 2 Normative references |
| 13 | 3 Terms and definitions |
| 14 | 4 Apparatus 4.1 General principle of the method 4.2 Equipment 4.2.1 Heating arrangement |
| 15 | 4.2.2 Test vessels 4.2.3 Absorption tubes 4.2.4 Filtering crucibles |
| 16 | 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 |
| 17 | 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 |
| 18 | 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 |
| 19 | 4.8.2 Soluble acidity (SA) 4.8.3 Volatile acidity (VA) |
| 20 | 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 |
| 21 | 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 |
| 22 | Figures Figure 1 – Typical 8 hole (4 x 2) aluminium heating block Figure 2 – Aluminium alloy temperature measuring block |
| 23 | Figure 3 – Position of the tube in the oil bath Figure 4 – Oxidation tube or absorption tube |
| 24 | Figure 5 – Oxidation tube and absorption tube assembly |
| 25 | Annexes Annex A (normative) Thermometer specifications Table A.1 – Thermometer specifications |
| 26 | 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 |
| 27 | B.3.3 Oxidation B.3.4 Determination of the induction period with oxygen B.3.5 Determinations on the oxidized oil (optional) |
| 28 | 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 |
| 29 | 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 |
| 30 | 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 |
| 31 | C.6 Precision Table C.1 – Precision data for headspace procedure according to Annex C |
| 32 | Bibliography |
Related products
-
BS EN IEC 61125:2018 – TC:2020 Edition
Tracked Changes. Insulating liquids. Test methods for oxidation stability. Test method for evaluating the oxidation…
-
BS EN IEC 61125:2018
Insulating liquids. Test methods for oxidation stability. Test method for evaluating the oxidation stability of…
