This document describes how the concentrations of dissolved gases or free gases can be interpreted to diagnose the condition of oil-filled electrical equipment in service and suggest future action. This document is applicable to electrical equipment filled with mineral insulating oil and insulated with cellulosic paper or pressboard-based solid insulation. Information about specific types of equipment such as transformers (power, instrument, industrial, railways, distribution), reactors, bushings, switchgear and oil-filled cables is given only as an indication in the application notes. This document can be applied, but only with caution, to other liquid-solid insulating systems. In any case, the indications obtained are given only as guidance with resulting action undertaken only with proper engineering judgment.<\/p>\n
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| 2<\/td>\n | undefined <\/td>\n<\/tr>\n | ||||||
| 5<\/td>\n | Annex ZA (normative)Normative references to international publicationswith their corresponding European publications <\/td>\n<\/tr>\n | ||||||
| 7<\/td>\n | English CONTENTS <\/td>\n<\/tr>\n | ||||||
| 10<\/td>\n | FOREWORD <\/td>\n<\/tr>\n | ||||||
| 12<\/td>\n | INTRODUCTION <\/td>\n<\/tr>\n | ||||||
| 13<\/td>\n | 1 Scope 2 Normative references 3 Terms, definitions and abbreviated terms 3.1 Terms and definitions <\/td>\n<\/tr>\n | ||||||
| 15<\/td>\n | 3.2 Abbreviated terms 3.2.1 Chemical names and formulae 3.2.2 General abbreviated terms <\/td>\n<\/tr>\n | ||||||
| 16<\/td>\n | 4 Mechanisms of gas formation 4.1 Decomposition of oil <\/td>\n<\/tr>\n | ||||||
| 17<\/td>\n | 4.2 Decomposition of cellulosic insulation 4.3 Stray gassing of oil 4.4 Other sources of gas 5 Identification of faults 5.1 General <\/td>\n<\/tr>\n | ||||||
| 18<\/td>\n | 5.2 Dissolved gas compositions 5.3 Types of faults 5.4 Basic gas ratios <\/td>\n<\/tr>\n | ||||||
| 19<\/td>\n | Tables Table 1 \u2013 DGA interpretation table Table 2 \u2013 Simplified scheme of interpretation <\/td>\n<\/tr>\n | ||||||
| 20<\/td>\n | 5.5 CO2\/CO ratio 5.6 O2\/N2 ratio <\/td>\n<\/tr>\n | ||||||
| 21<\/td>\n | 5.7 C2H2\/H2 ratio 5.8 C3 hydrocarbons 5.9 Evolution of faults 5.10 Graphical representations <\/td>\n<\/tr>\n | ||||||
| 22<\/td>\n | 6 Conditions for calculating ratios 6.1 Examination of DGA values 6.2 Uncertainty on gas ratios 7 Application to free gases in gas relays <\/td>\n<\/tr>\n | ||||||
| 24<\/td>\n | 8 Gas concentration levels in service 8.1 Probability of failure in service 8.1.1 General Table 3 \u2013 Ostwald solubility coefficients for various gases in mineral insulating oils <\/td>\n<\/tr>\n | ||||||
| 25<\/td>\n | 8.1.2 Calculation methods 8.2 Typical concentration values 8.2.1 General 8.2.2 Calculation methods 8.2.3 Choice of normality percentages 8.2.4 Alarm concentration values <\/td>\n<\/tr>\n | ||||||
| 26<\/td>\n | 8.3 Rates of gas increase 9 Recommended method of DGA interpretation <\/td>\n<\/tr>\n | ||||||
| 27<\/td>\n | 10 Report of results <\/td>\n<\/tr>\n | ||||||
| 28<\/td>\n | Figures Figure 1 \u2013 Flow chart <\/td>\n<\/tr>\n | ||||||
| 29<\/td>\n | Annex A (informative) Equipment application notes A.1 General warning A.2 Power transformers A.2.1 Specific subtypes A.2.2 Typical faults <\/td>\n<\/tr>\n | ||||||
| 30<\/td>\n | A.2.3 Identification of faults by DGA A.2.4 Typical concentration values Table A.1 \u2013 Typical faults in power transformers <\/td>\n<\/tr>\n | ||||||
| 31<\/td>\n | A.2.5 Typical rates of gas increase Table A.2 \u2013 Ranges of 90 % typical gas concentration values observed in power transformers Table A.3 \u2013 Ranges of 90 % typical rates of gas increase observed in power transformers (all types) <\/td>\n<\/tr>\n | ||||||
| 32<\/td>\n | A.2.6 Specific information to be added to the DGA report A.3 Industrial and special transformers A.3.1 Specific subtypes A.3.2 Typical faults <\/td>\n<\/tr>\n | ||||||
| 33<\/td>\n | A.3.3 Identification of faults by DGA A.3.4 Typical concentration values Table A.4 \u2013 Examples of 90 % typical concentration values observed on individual networks Table A.5 \u2013 Ranges of 90 % typical concentration values observed in WTTs <\/td>\n<\/tr>\n | ||||||
| 34<\/td>\n | A.4 Instrument transformers A.4.1 Specific subtypes A.4.2 Typical faults A.4.3 Identification of faults by DGA Table A.6 \u2013 Typical faults in instrument transformers <\/td>\n<\/tr>\n | ||||||
| 35<\/td>\n | A.4.4 Typical concentration values A.5 Oil-impregnated paper bushings A.5.1 Specific subtypes A.5.2 Typical faults Table A.7 \u2013 Ranges of 90 % typical concentration values observed in instrument transformers Table A.8 \u2013 Maximum admissible values for sealed instrument transformers <\/td>\n<\/tr>\n | ||||||
| 36<\/td>\n | A.5.3 Identification of faults by DGA A.5.4 Typical concentration values Table A.9 \u2013 Typical faults in bushings Table A.10 \u2013 Simplified interpretation scheme for bushings <\/td>\n<\/tr>\n | ||||||
| 37<\/td>\n | A.6 Oil-filled cables A.6.1 Typical faults A.6.2 Identification of faults by DGA A.6.3 Typical concentration values Table A.11 \u2013 Ranges of 90 % typical concentration values in bushings <\/td>\n<\/tr>\n | ||||||
| 38<\/td>\n | A.7 Switching equipment A.7.1 Specific subtypes A.7.2 Normal operation A.7.3 Typical faults A.7.4 Identification of faults by DGA Table A.12 \u2013 Ranges of 95 % typical concentration values observed on cables Table A.13 \u2013 Typical faults in switching equipment <\/td>\n<\/tr>\n | ||||||
| 39<\/td>\n | A.8 Equipment filled with non-mineral fluids <\/td>\n<\/tr>\n | ||||||
| 40<\/td>\n | Annex B (informative) Graphical representations of gas ratios Figure B.1 \u2013 Graphical representation 1 of gas ratios <\/td>\n<\/tr>\n | ||||||
| 41<\/td>\n | Figure B.2 \u2013 Graphical representation 2 of gas ratios <\/td>\n<\/tr>\n | ||||||
| 42<\/td>\n | Figure B.3 \u2013 Graphical representation 3 of gas ratios \u2013 Duval’s triangle 1 for transformers, bushings and cables <\/td>\n<\/tr>\n | ||||||
| 43<\/td>\n | Figure B.4 \u2013 Graphical representation 4 of gas ratios \u2013 Duval’s triangle 2 for OLTCs (see A.7.2) <\/td>\n<\/tr>\n<\/table>\n","protected":false},"excerpt":{"rendered":" Mineral oil-filled electrical equipment in service. Guidance on the interpretation of dissolved and free gases analysis<\/b><\/p>\n |