BS EN 60076-2:2011
$198.66
Power transformers – Temperature rise for liquid-immersed transformers
| Published By | Publication Date | Number of Pages |
| BSI | 2011 | 52 |
IEC 60076-2:2011 applies to liquid-immersed transformers, identifies power transformers according to their cooling methods, defines temperature rise limits and gives the methods for temperature rise tests. This new edition includes the following significant technical changes with respect to the previous edition: – the winding hot-spot temperature rise limit was introduced among the prescriptions; – the procedures for the temperature rise test were improved in relation to the new thermal requirements; – five informative annexes were added in order to facilitate the implementation of this standard.
PDF Catalog
| PDF Pages | PDF Title |
|---|---|
| 6 | English CONTENTS |
| 8 | 1 Scope 2 Normative references 3 Terms and definitions |
| 10 | 4 Cooling methods 4.1 Identification symbols |
| 11 | 4.2 Transformers with alternative cooling methods 5 Normal cooling conditions 5.1 Air-cooled transformers |
| 12 | 5.2 Water-cooled transformers 6 Temperature rise limits 6.1 General 6.2 Temperature rise limits at rated power |
| 13 | Tables Table 1 – Temperature rise limits |
| 14 | 6.3 Modified requirements for special cooling conditions Table 2 – Recommended values of temperature rise corrections in case of special service conditions |
| 15 | 6.4 Temperature rise during a specified load cycle 7 Temperature rise tests 7.1 General 7.2 Temperature of the cooling media |
| 16 | 7.3 Test methods for temperature rise determination |
| 18 | 7.4 Determination of liquid temperatures |
| 20 | 7.5 Determination of top, average and bottom liquid temperature rises 7.6 Determination of average winding temperature |
| 21 | 7.7 Determination of winding resistance at the instant of shutdown 7.8 Determination of average winding temperature rise at the instant of shutdown 7.9 Determination of the average winding to liquid temperature gradient |
| 22 | 7.10 Determination of the hot-spot winding temperature rise |
| 23 | 7.11 Uncertainties affecting the results of the temperature rise test 7.12 Dissolved gas-in-oil analysis 7.13 Corrections |
| 24 | Table 3 – Exponents for the corrections of temperature rise test results |
| 25 | Annex A (informative) Hot-spot winding temperature rise determination for OFAF and OFWF cooled transformers based on the top-liquid temperature in tank |
| 26 | Table A.1 – Hot-spot winding temperature rises for some specific transformers determined from conventional heat run test data combined with calculated hot-spot winding temperature rise, and from direct fibre-optic measurements |
| 27 | Annex B (informative) Methods to estimate the hot-spot winding temperature rises |
| 28 | Figures Figure B.1 – Temperature rise distribution model for ON cooling methods |
| 29 | Figure B.2 – Value of factor as a function of rated power and strand height (W) |
| 30 | Figure B.3 – Typical liquid flow paths in a disk winding with diverting washers |
| 32 | Annex C (informative) Techniques used in temperature rise testingof liquid-immersed transformers |
| 34 | Figure C.1 – Recommended circuit for transformers with a low resistance winding using two separate direct current sources, one for each winding Figure C.2 – Alternative recommended circuit using only one direct current source for both windings |
| 35 | Figure C.3 – Average winding temperature variation after shutdown |
| 39 | Table C.1 – Example of cooling down curve calculation spreadsheet |
| 40 | Figure C.4 – Extrapolation of the cooling down curve, using the fitting curve |
| 41 | Annex D (informative) Dissolved gases analysis for the detection of local overheating |
| 42 | Table D.1 – Minimum detectable value SD of gases in oil |
| 43 | Table D.2 – Admissible limits for gas rate increases |
| 45 | Annex E (informative) Application of optical fibre sensors for winding hot-spot measurements Table E.1 – Minimum recommended number of sensors for three-phase transformers Table E.2 – Minimum recommended number of sensors for single-phase transformers |
| 47 | Figure E.1 – Optical fibre sensor application for a disk winding of core type transformer Figure E.2 – Optical fibre sensor application for a transposed cable of core type transformer |
| 48 | Figure E.3 – Modality of optical fibre sensor application in the winding spacer of core type transformer Figure E.4 – Optical fibre sensor application for high voltage winding of shell type transformer |
| 49 | Bibliography |
