IEC 62475:2010 is applicable to high-current testing and measurements on both high-voltage and low-voltage equipment. It deals with steady-state and short-time direct current (as e.g. encountered in high-power d.c. testing), steady-state and short-time alternating current (as e.g. encountered in high-power a.c. testing), and impulse-current. In general, currents above 100 A are considered in this International Standard, although currents less than this can occur in tests. This standard also covers fault detection during, for example, lightning impulse testing.<\/p>\n
| PDF Pages<\/th>\n | PDF Title<\/th>\n<\/tr>\n | ||||||
|---|---|---|---|---|---|---|---|
| 7<\/td>\n | English CONTENTS <\/td>\n<\/tr>\n | ||||||
| 13<\/td>\n | 1 Scope 2 Normative references 3 Terms and definitions <\/td>\n<\/tr>\n | ||||||
| 14<\/td>\n | 3.1 Measuring systems 3.2 Components of a measuring system <\/td>\n<\/tr>\n | ||||||
| 15<\/td>\n | 3.3 Scale factors <\/td>\n<\/tr>\n | ||||||
| 16<\/td>\n | 3.4 Rated values 3.5 Definitions related to the dynamic behaviour <\/td>\n<\/tr>\n | ||||||
| 17<\/td>\n | 3.6 Definitions related to uncertainty Figures Figure 1 \u2013 Examples of amplitude frequency responses for limit frequencies (f1; f2) Upper and lower limits frequencies are shown on curve A. Curve B shows a constant response down to direct current <\/td>\n<\/tr>\n | ||||||
| 19<\/td>\n | 3.7 Definitions related to tests on measuring systems <\/td>\n<\/tr>\n | ||||||
| 20<\/td>\n | 4 Procedures for qualification and use of a measuring system 4.1 General principles 4.2 Schedule of performance tests 4.3 Schedule of performance checks <\/td>\n<\/tr>\n | ||||||
| 21<\/td>\n | 4.4 Requirements for the record of performance 4.5 Operating conditions <\/td>\n<\/tr>\n | ||||||
| 22<\/td>\n | 4.6 Uncertainty <\/td>\n<\/tr>\n | ||||||
| 23<\/td>\n | 5 Tests and test requirements for an approved measuring system 5.1 General requirements 5.2 Calibration \u2013 Determination of the scale factor <\/td>\n<\/tr>\n | ||||||
| 25<\/td>\n | Figure\u00a02 \u2013 Calibration by comparison over full assigned measurement range <\/td>\n<\/tr>\n | ||||||
| 26<\/td>\n | Figure\u00a03 \u2013 Uncertainty contributions of the calibration (example with the minimum of 5 current levels) <\/td>\n<\/tr>\n | ||||||
| 27<\/td>\n | Figure\u00a04 \u2013 Calibration by comparison over a limited current range with a linearity test (see \u200e5.3) providing extension up to the largest value in the assigned measurement range <\/td>\n<\/tr>\n | ||||||
| 28<\/td>\n | 5.3 Linearity test <\/td>\n<\/tr>\n | ||||||
| 29<\/td>\n | 5.4 Dynamic behaviour Figure 5 \u2013 Linearity test of the measuring system with a linear device in the extended voltage range <\/td>\n<\/tr>\n | ||||||
| 30<\/td>\n | 5.5 Short-term stability <\/td>\n<\/tr>\n | ||||||
| 31<\/td>\n | Figure\u00a06 \u2013 Short-term stability test for steady-state current Figure\u00a07 \u2013 Short-term stability test for impulse current and short-time current <\/td>\n<\/tr>\n | ||||||
| 32<\/td>\n | 5.6 Long-term stability 5.7 Ambient temperature effect Figure\u00a08 \u2013 Short-term stability test for periodic impulse-current and periodic short-time current <\/td>\n<\/tr>\n | ||||||
| 33<\/td>\n | 5.8 Effect of nearby current paths <\/td>\n<\/tr>\n | ||||||
| 34<\/td>\n | Figure\u00a09 \u2013 Test circuit for effect of nearby current path for current-converting shunts and current transformers with iron Figure\u00a010 \u2013 Test circuit for effect of nearby current path for inductive measuring systems without iron (Rogowski coils) <\/td>\n<\/tr>\n | ||||||
| 35<\/td>\n | 5.9 Software effect 5.10 Uncertainty calculation <\/td>\n<\/tr>\n | ||||||
| 37<\/td>\n | 5.11 Uncertainty calculation of time-parameter measurements (impulse currents only) <\/td>\n<\/tr>\n | ||||||
| 39<\/td>\n | 5.12 Interference test <\/td>\n<\/tr>\n | ||||||
| 40<\/td>\n | Figure\u00a011 \u2013 Principle of interference test circuit Figure\u00a012\u00a0\u2013\u00a0Interference test on the measuring system i1(t) based on current converting shunt or current transformer with iron in a typical 3 phase short circuit set up (example) <\/td>\n<\/tr>\n | ||||||
| 41<\/td>\n | 5.13 Withstand tests Figure\u00a013 \u2013 Test circuit for interference test for inductive systems without iron <\/td>\n<\/tr>\n | ||||||
| 42<\/td>\n | 6 Steady-state direct current 6.1 Application 6.2 Terms and definitions 6.3 Test current <\/td>\n<\/tr>\n | ||||||
| 43<\/td>\n | 6.4 Measurement of the test current Tables Table\u00a01 \u2013 Required tests for steady-state direct current <\/td>\n<\/tr>\n | ||||||
| 44<\/td>\n | 6.5 Measurement of ripple amplitude <\/td>\n<\/tr>\n | ||||||
| 45<\/td>\n | Table\u00a02 \u2013 Required tests for ripple current <\/td>\n<\/tr>\n | ||||||
| 46<\/td>\n | 6.6 Test procedures 7 Steady-state alternating current 7.1 Application 7.2 Terms and definitions 7.3 Test current <\/td>\n<\/tr>\n | ||||||
| 47<\/td>\n | 7.4 Measurement of the test current <\/td>\n<\/tr>\n | ||||||
| 48<\/td>\n | Figure\u00a014 \u2013 Acceptable normalized amplitude-frequency response of an a.c. measuring system intended for a single fundamental frequency fnom <\/td>\n<\/tr>\n | ||||||
| 49<\/td>\n | Figure\u00a015 \u2013 Acceptable normalized amplitude-frequency response of an a.c. measuring system intended for a range of fundamental frequencies fnom1 to fnom2 Table\u00a03 \u2013 Required tests for steady-state alternating current <\/td>\n<\/tr>\n | ||||||
| 50<\/td>\n | 7.5 Test procedures 8 Short-time direct current 8.1 Application <\/td>\n<\/tr>\n | ||||||
| 51<\/td>\n | 8.2 Terms and definitions Figure\u00a016 \u2013 Example of short-time direct current <\/td>\n<\/tr>\n | ||||||
| 52<\/td>\n | 8.3 Test currents 8.4 Measurement of the test current Table\u00a04 \u2013 Tolerance requirement on test-current parameters for short-time direct current <\/td>\n<\/tr>\n | ||||||
| 53<\/td>\n | Table\u00a05 \u2013 Required tests for short-time direct current <\/td>\n<\/tr>\n | ||||||
| 54<\/td>\n | 8.5 Test procedures 9 Short-time alternating current 9.1 Application <\/td>\n<\/tr>\n | ||||||
| 55<\/td>\n | 9.2 Terms and definitions Figure\u00a017 \u2013 Example of short-time alternating current <\/td>\n<\/tr>\n | ||||||
| 56<\/td>\n | 9.3 Test current Table\u00a06 \u2013 Tolerance requirements on the short-time alternating current test parameters <\/td>\n<\/tr>\n | ||||||
| 57<\/td>\n | 9.4 Measurement of the test current Table\u00a07 \u2013 List of typical tests in a high-power laboratory and required minimum frequency range of the measuring system <\/td>\n<\/tr>\n | ||||||
| 58<\/td>\n | Table\u00a08 \u2013 Tolerance requirements on scale factor Table\u00a09 \u2013 Required tests for short-time alternating current <\/td>\n<\/tr>\n | ||||||
| 60<\/td>\n | 9.5 Test procedures 10 Impulse currents 10.1 Application 10.2 Terms and definitions <\/td>\n<\/tr>\n | ||||||
| 61<\/td>\n | Figure\u00a018 \u2013 Exponential impulse current Figure\u00a019 \u2013 Exponential impulse current \u2013 Oscillating tail <\/td>\n<\/tr>\n | ||||||
| 62<\/td>\n | Figure\u00a020 \u2013 Impulse current \u2013 Rectangular, smooth Figure\u00a021 \u2013 Impulse current \u2013 Rectangular with oscillations <\/td>\n<\/tr>\n | ||||||
| 64<\/td>\n | 10.3 Test current Table\u00a010 \u2013 Examples of exponential impulse-current types <\/td>\n<\/tr>\n | ||||||
| 65<\/td>\n | 10.4 Measurement of the test current <\/td>\n<\/tr>\n | ||||||
| 67<\/td>\n | Table\u00a011 \u2013 Required tests for impulse current <\/td>\n<\/tr>\n | ||||||
| 68<\/td>\n | 10.5 Test procedures 11 Current measurement in high-voltage dielectric testing 11.1 Application 11.2 Terms and definitions <\/td>\n<\/tr>\n | ||||||
| 69<\/td>\n | 11.3 Measurement of the test current Table\u00a012 \u2013 Required tests for impulse current in high-voltage dielectric testing <\/td>\n<\/tr>\n | ||||||
| 70<\/td>\n | 11.4 Test procedures 12 Reference measuring systems 12.1 General 12.2 Interval between subsequent calibrations of reference measuring systems <\/td>\n<\/tr>\n | ||||||
| 71<\/td>\n | Annex A (informative) Uncertainty of measurement <\/td>\n<\/tr>\n | ||||||
| 76<\/td>\n | Table\u00a0A.1 \u2013 Coverage factor k for effective degrees of freedom \u03bdeff (p\u00a0=\u00a095,45\u00a0%) <\/td>\n<\/tr>\n | ||||||
| 77<\/td>\n | Table\u00a0A.2 \u2013 Schematic of an uncertainty budget <\/td>\n<\/tr>\n | ||||||
| 78<\/td>\n | Figure\u00a0A.1 \u2013 Normal probability distribution p(x) of a continuous random variable x Figure\u00a0A.2 \u2013 Rectangular symmetric probability distribution p(x) of the estimate x of an input quantity X <\/td>\n<\/tr>\n | ||||||
| 79<\/td>\n | Annex B (informative) Examples of the uncertainty calculation in high-current measurements <\/td>\n<\/tr>\n | ||||||
| 81<\/td>\n | Table B.1 \u2013 Result of the comparison measurement Table\u00a0B.2 \u2013 Result of the comparison measurement <\/td>\n<\/tr>\n | ||||||
| 82<\/td>\n | Table B.3 \u2013 Uncertainty budget for calibration of scale factor Fx <\/td>\n<\/tr>\n | ||||||
| 83<\/td>\n | Table\u00a0B.4 \u2013 Result of linearity test <\/td>\n<\/tr>\n | ||||||
| 84<\/td>\n | Figure\u00a0B.1 \u2013 Comparison between the system under calibration X and the reference system N Table B.5 \u2013 Uncertainty budget of scale factor FX,mes <\/td>\n<\/tr>\n | ||||||
| 85<\/td>\n | Annex C (informative) Step-response measurements Figure\u00a0C.1 \u2013 Circuit to generate current step using a coaxial cable Figure\u00a0C.2 \u2013 Circuit to generate current step using a capacitor <\/td>\n<\/tr>\n | ||||||
| 87<\/td>\n | Figure C.3 \u2013 Definition of response parameters with respect to step response <\/td>\n<\/tr>\n | ||||||
| 88<\/td>\n | Annex D (informative) Convolution method for estimation of dynamic behaviour from step-response measurements <\/td>\n<\/tr>\n | ||||||
| 91<\/td>\n | Annex E (informative) Constraints for certain wave shapes Figure\u00a0E.1 \u2013 Attainable combinations of time parameters (shaded area) for the 8\/20 impulse at maximum 20\u00a0% undershoot and for 20\u00a0% tolerance on the time parameters <\/td>\n<\/tr>\n | ||||||
| 92<\/td>\n | Figure\u00a0E.2 \u2013 Locus for limit of attainable time parameters as a function of permissible undershoot for the 8\/20 impulse Figure\u00a0E.3 \u2013 Locus for limit of attainable time parameters as a function of permissible undershoot for the 30\/80 impulse <\/td>\n<\/tr>\n | ||||||
| 93<\/td>\n | Annex F (informative) Temperature rise of measuring resistors <\/td>\n<\/tr>\n | ||||||
| 94<\/td>\n | Annex G (informative) Determination of r.m.s. values of short-time a.c. current Figure\u00a0G.1 \u2013 Equivalent circuit of short-circuit test <\/td>\n<\/tr>\n | ||||||
| 95<\/td>\n | Figure\u00a0G.2 \u2013 Symmetrical a.c. component of an alternating short-circuit current <\/td>\n<\/tr>\n | ||||||
| 96<\/td>\n | Figure G.3 \u2013 Numerical evaluation of r.m.s value showing both instantaneous current and instantaneous squared value of the current <\/td>\n<\/tr>\n | ||||||
| 97<\/td>\n | Figure G.4 \u2013 Three-crest method <\/td>\n<\/tr>\n | ||||||
| 98<\/td>\n | Figure G.5 \u2013 Evaluation of conventional r.m.s. value of an arc current using the three-crest method <\/td>\n<\/tr>\n | ||||||
| 99<\/td>\n | Figure G.6 \u2013 Evaluation of equivalent r.m.s value of a short-time current during a short-circuit test <\/td>\n<\/tr>\n | ||||||
| 100<\/td>\n | Figure G.7 \u2013 Relation between peak factor k and power factor cos(q). <\/td>\n<\/tr>\n | ||||||
| 101<\/td>\n | Annex H (informative) Examples of IEC standards with high-current tests Table H.1 \u2013 List of typical tests with short-time alternating current <\/td>\n<\/tr>\n | ||||||
| 102<\/td>\n | Table H.2 \u2013 List of typical tests with exponential impulse current Table H.3 \u2013 List of typical tests with rectangular impulse current <\/td>\n<\/tr>\n | ||||||
| 103<\/td>\n | Bibliography <\/td>\n<\/tr>\n<\/table>\n","protected":false},"excerpt":{"rendered":" High-current test techniques. Definitions and requirements for test currents and measuring systems<\/b><\/p>\n |