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.<\/p>\n
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| 2<\/td>\n | undefined <\/td>\n<\/tr>\n | ||||||
| 6<\/td>\n | English CONTENTS <\/td>\n<\/tr>\n | ||||||
| 9<\/td>\n | FOREWORD <\/td>\n<\/tr>\n | ||||||
| 11<\/td>\n | INTRODUCTION <\/td>\n<\/tr>\n | ||||||
| 12<\/td>\n | 1 Scope 2 Normative references 3 Terms and definitions <\/td>\n<\/tr>\n | ||||||
| 14<\/td>\n | 4 Insulation resistance \u2013 components and influence factors 5 Polarization index Figures Figure 1 \u2013 Equivalent circuit diagram of winding insulation in a DC voltage test <\/td>\n<\/tr>\n | ||||||
| 15<\/td>\n | 6 Measurement 6.1 Influences on the measurement of the insulation resistance 6.1.1 General 6.1.2 Winding temperature correction <\/td>\n<\/tr>\n | ||||||
| 16<\/td>\n | 6.2 Measuring equipment Tables Table 1 \u2013 Values of the parameter X for the temperature correction <\/td>\n<\/tr>\n | ||||||
| 17<\/td>\n | 6.3 Test object and measuring circuit 6.3.1 General 6.3.2 Three-phase stator windings <\/td>\n<\/tr>\n | ||||||
| 18<\/td>\n | 6.3.3 Other windings Figure 2 \u2013 Connection for testing of the entire winding Figure 3 \u2013 Connection for phase-to-earth measurement <\/td>\n<\/tr>\n | ||||||
| 19<\/td>\n | 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 \u2013 Guidelines for DC voltage magnitudes to be applied during the insulation resistance measurement <\/td>\n<\/tr>\n | ||||||
| 20<\/td>\n | 6.7.2 Special procedures 7 Interpretation of measurement results 7.1 General 7.2 Suitability for testing and operation <\/td>\n<\/tr>\n | ||||||
| 21<\/td>\n | 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 <\/td>\n<\/tr>\n | ||||||
| 22<\/td>\n | 8 Recommended limits of insulation resistance and polarization index 8.1 General 8.2 Insulation resistance 8.3 Polarization index Table 3 \u2013 Recommended minimum insulation resistance values at a base temperature of 40 \u00b0C <\/td>\n<\/tr>\n | ||||||
| 23<\/td>\n | 9 Test report 9.1 Operational aged windings Table 4 \u2013 Recommended minimum values of polarization index for high voltage insulation systems <\/td>\n<\/tr>\n | ||||||
| 24<\/td>\n | 9.2 New windings <\/td>\n<\/tr>\n | ||||||
| 25<\/td>\n | Annex A (informative)Components of the direct current A.1 Total current IT A.2 Capacitive current IC Figure A.1 \u2013 Relationships between different currents and time <\/td>\n<\/tr>\n | ||||||
| 26<\/td>\n | A.3 Conduction current IG <\/td>\n<\/tr>\n | ||||||
| 27<\/td>\n | A.4 Polarization current IP <\/td>\n<\/tr>\n | ||||||
| 28<\/td>\n | A.5 Surface leakage current IL A.6 Stress control coating current IS <\/td>\n<\/tr>\n | ||||||
| 29<\/td>\n | Annex B (informative)Graphical estimation of the slope parameter X for temperature correction from measurement data Table B.1 \u2013 Example data from insulation resistancemeasurements at different winding temperatures <\/td>\n<\/tr>\n | ||||||
| 30<\/td>\n | Figure B.1 \u2013 Graphical estimation of the slope parameter X in a semi-logarithmic diagram <\/td>\n<\/tr>\n | ||||||
| 31<\/td>\n | 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 \u2013 Total current versus time on a clean and dry insulation.The scales are logarithmic <\/td>\n<\/tr>\n | ||||||
| 32<\/td>\n | C.2 Machine with a wet and contaminated surface Figure C.2 \u2013 Insulation resistance versus timeon a clean and dry insulation Figure C.3 \u2013 Total current versus time on a wetand contaminated insulation <\/td>\n<\/tr>\n | ||||||
| 33<\/td>\n | 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 \u2013 Insulation resistance versus time on a wet and contaminated insulation <\/td>\n<\/tr>\n | ||||||
| 34<\/td>\n | C.3.2 Effects on insulation resistance and polarization index C.3.3 Examples of test results Figure C.5 \u2013 Total current versus time on a dry and clean surface with a continuous stress control coating <\/td>\n<\/tr>\n | ||||||
| 35<\/td>\n | Figure C.6 \u2013 Insulation resistance versus time on a dry and clean surface with a stress control coating <\/td>\n<\/tr>\n | ||||||
| 36<\/td>\n | Annex D (informative)Measurement of leakage current to assessinterphase insulation resistance Figure D.1 \u2013 Connection for phase-to-phase measurement. The test instrument shall be floating with respect to earth. Other phase to phase combinations are permitted <\/td>\n<\/tr>\n | ||||||
| 37<\/td>\n | Figure D.2 \u2013 Measurement of interphase leakage current with a measurement instrument equipped with a guard connection Figure D.3 \u2013 Measurement of interphase leakage current with a measurement instrument not equipped with a guard connection <\/td>\n<\/tr>\n | ||||||
| 38<\/td>\n | Annex E (informative)Other DC tests E.1 General E.2 Dielectric absorption ratio (DAR) <\/td>\n<\/tr>\n | ||||||
| 39<\/td>\n | E.3 Monitoring charge and discharge currents Figure E.1 \u2013 Measurement of current and insulation resistance that results in a DAR of 1,09 <\/td>\n<\/tr>\n | ||||||
| 40<\/td>\n | Figure E.2 \u2013 Charge and discharge currents after a step voltage of 2,5 kV for the three-phase windings of a 50 MVA hydro-generator: <\/td>\n<\/tr>\n | ||||||
| 41<\/td>\n | 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 <\/td>\n<\/tr>\n | ||||||
| 42<\/td>\n | E.5 Wet insulation resistance measurement <\/td>\n<\/tr>\n | ||||||
| 43<\/td>\n | Bibliography <\/td>\n<\/tr>\n<\/table>\n","protected":false},"excerpt":{"rendered":" Rotating electrical machines – Measurement of insulation resistance and polarization index on winding insulation of rotating electrical machines<\/b><\/p>\n |