BS EN IEC 60034-27-4:2018
$167.15
Rotating electrical machines – Measurement of insulation resistance and polarization index on winding insulation of rotating electrical machines
| Published By | Publication Date | Number of Pages |
| BSI | 2018 | 44 |
IEC 60034-27-4:2018 provides recommended test procedures for the measurement of insulation resistance and polarization index of stator and rotor winding insulation of rotating electrical machines. This document recommends minimum acceptable values of insulation resistance and polarization index of winding insulation valid for fully processed low and high voltage AC and DC rotating electrical machines with a rated power of 750 W or higher.
PDF Catalog
| PDF Pages | PDF Title |
|---|---|
| 2 | undefined |
| 6 | English CONTENTS |
| 9 | FOREWORD |
| 11 | INTRODUCTION |
| 12 | 1 Scope 2 Normative references 3 Terms and definitions |
| 14 | 4 Insulation resistance – components and influence factors 5 Polarization index Figures Figure 1 – Equivalent circuit diagram of winding insulation in a DC voltage test |
| 15 | 6 Measurement 6.1 Influences on the measurement of the insulation resistance 6.1.1 General 6.1.2 Winding temperature correction |
| 16 | 6.2 Measuring equipment Tables Table 1 – Values of the parameter X for the temperature correction |
| 17 | 6.3 Test object and measuring circuit 6.3.1 General 6.3.2 Three-phase stator windings |
| 18 | 6.3.3 Other windings Figure 2 – Connection for testing of the entire winding Figure 3 – Connection for phase-to-earth measurement |
| 19 | 6.4 Measuring voltage 6.4.1 Type and magnitude 6.4.2 Polarity 6.5 Measuring time 6.6 Safety 6.7 Measurement procedures 6.7.1 Standard procedure Table 2 – Guidelines for DC voltage magnitudes to be applied during the insulation resistance measurement |
| 20 | 6.7.2 Special procedures 7 Interpretation of measurement results 7.1 General 7.2 Suitability for testing and operation |
| 21 | 7.3 Trending of insulation condition 7.4 Comparison between machines or between phases 7.5 Effects at very high values of insulation resistance 7.6 Limitations of the insulation resistance test |
| 22 | 8 Recommended limits of insulation resistance and polarization index 8.1 General 8.2 Insulation resistance 8.3 Polarization index Table 3 – Recommended minimum insulation resistance values at a base temperature of 40 °C |
| 23 | 9 Test report 9.1 Operational aged windings Table 4 – Recommended minimum values of polarization index for high voltage insulation systems |
| 24 | 9.2 New windings |
| 25 | Annex A (informative)Components of the direct current A.1 Total current IT A.2 Capacitive current IC Figure A.1 – Relationships between different currents and time |
| 26 | A.3 Conduction current IG |
| 27 | A.4 Polarization current IP |
| 28 | A.5 Surface leakage current IL A.6 Stress control coating current IS |
| 29 | Annex B (informative)Graphical estimation of the slope parameter X for temperature correction from measurement data Table B.1 – Example data from insulation resistancemeasurements at different winding temperatures |
| 30 | Figure B.1 – Graphical estimation of the slope parameter X in a semi-logarithmic diagram |
| 31 | Annex C (informative)Examples of test results of syntheticresin based high voltage windings C.1 Machine with dry and clean surface of the insulation Figure C.1 – Total current versus time on a clean and dry insulation.The scales are logarithmic |
| 32 | C.2 Machine with a wet and contaminated surface Figure C.2 – Insulation resistance versus timeon a clean and dry insulation Figure C.3 – Total current versus time on a wetand contaminated insulation |
| 33 | C.3 Machine with continuous stress control layers in galvanic contact with high voltage conductors C.3.1 Stress control coating current IS Figure C.4 – Insulation resistance versus time on a wet and contaminated insulation |
| 34 | C.3.2 Effects on insulation resistance and polarization index C.3.3 Examples of test results Figure C.5 – Total current versus time on a dry and clean surface with a continuous stress control coating |
| 35 | Figure C.6 – Insulation resistance versus time on a dry and clean surface with a stress control coating |
| 36 | Annex D (informative)Measurement of leakage current to assessinterphase insulation resistance Figure D.1 – Connection for phase-to-phase measurement. The test instrument shall be floating with respect to earth. Other phase to phase combinations are permitted |
| 37 | Figure D.2 – Measurement of interphase leakage current with a measurement instrument equipped with a guard connection Figure D.3 – Measurement of interphase leakage current with a measurement instrument not equipped with a guard connection |
| 38 | Annex E (informative)Other DC tests E.1 General E.2 Dielectric absorption ratio (DAR) |
| 39 | E.3 Monitoring charge and discharge currents Figure E.1 – Measurement of current and insulation resistance that results in a DAR of 1,09 |
| 40 | Figure E.2 – Charge and discharge currents after a step voltage of 2,5 kV for the three-phase windings of a 50 MVA hydro-generator: |
| 41 | E.4 High voltage DC tests E.4.1 General E.4.2 Uniform-time voltage step test E.4.3 Graded-time voltage step test E.4.4 Ramped-time voltage step test |
| 42 | E.5 Wet insulation resistance measurement |
| 43 | Bibliography |
