IEC 60071-2:2018 is now available as \/2 which contains the International Standard and its Redline version, showing all changes of the technical content compared to the previous edition. <\/p>\n
IEC 60071-2:2018 constitutes application guidelines and deals with the selection of insulation levels of equipment or installations for three-phase electrical systems. It gives guidance for the determination of the rated withstand voltages for ranges I and II of IEC 60071-1 and to justify the association of these rated values with the standardized highest voltages for equipment. It covers three-phase systems with nominal voltages above 1 kV. It has the status of a horizontal standard in accordance with IEC Guide 108. This edition includes the following significant technical changes with respect to the previous edition: a) the annex on clearance in air to assure a specified impulse withstand voltage installation is deleted because the annex in IEC 60071-1 is overlapped; b) 4.2 and 4.3 on surge arresters are updated; c) 4.3.5 on very-fast-front overvoltages is revised. Annex J on insulation co-ordination for very-fast-front overvoltages in UHV substations is added; d) Annex H on atmospheric correction \u2013 altitude correction is added. e) Annex I on evaluation method of non-standard lightning overvoltage shape is added.<\/p>\n
| PDF Pages<\/th>\n | PDF Title<\/th>\n<\/tr>\n | ||||||
|---|---|---|---|---|---|---|---|
| 199<\/td>\n | undefined <\/td>\n<\/tr>\n | ||||||
| 203<\/td>\n | English CONTENTS <\/td>\n<\/tr>\n | ||||||
| 209<\/td>\n | FOREWORD <\/td>\n<\/tr>\n | ||||||
| 211<\/td>\n | 1 Scope 2 Normative references <\/td>\n<\/tr>\n | ||||||
| 212<\/td>\n | 3 Terms, definitions, abbreviated terms and symbols 3.1 Terms and definitions 3.2 Abbreviated terms 3.3 Symbols <\/td>\n<\/tr>\n | ||||||
| 217<\/td>\n | 4 Representative voltage stresses in service 4.1 Origin and classification of voltage stresses <\/td>\n<\/tr>\n | ||||||
| 218<\/td>\n | 4.2 Characteristics of overvoltage protection devices 4.2.1 General remarks 4.2.2 Metal-oxide surge arresters without gaps (MOSA) <\/td>\n<\/tr>\n | ||||||
| 220<\/td>\n | 4.2.3 Line surge arresters (LSA) for overhead transmission and distribution lines 4.3 Representative voltages and overvoltages 4.3.1 Continuous (power-frequency) voltage <\/td>\n<\/tr>\n | ||||||
| 221<\/td>\n | 4.3.2 Temporary overvoltages <\/td>\n<\/tr>\n | ||||||
| 224<\/td>\n | 4.3.3 Slow-front overvoltages <\/td>\n<\/tr>\n | ||||||
| 226<\/td>\n | Figures Figure 1 \u2013 Range of 2 % slow-front overvoltages at the receiving end due to line energization and re-energization <\/td>\n<\/tr>\n | ||||||
| 227<\/td>\n | Figure 2 \u2013 Ratio between the 2 % values of slow-front overvoltages phase-to-phase and phase-to-earth <\/td>\n<\/tr>\n | ||||||
| 230<\/td>\n | 4.3.4 Fast-front overvoltages <\/td>\n<\/tr>\n | ||||||
| 234<\/td>\n | 4.3.5 Very-fast-front overvoltages [13] Figure 3 \u2013 Diagram for surge arrester connection to the protected object <\/td>\n<\/tr>\n | ||||||
| 235<\/td>\n | 5 Co-ordination withstand voltage 5.1 Insulation strength characteristics 5.1.1 General <\/td>\n<\/tr>\n | ||||||
| 236<\/td>\n | 5.1.2 Influence of polarity and overvoltage shapes <\/td>\n<\/tr>\n | ||||||
| 237<\/td>\n | 5.1.3 Phase-to-phase and longitudinal insulation 5.1.4 Influence of weather conditions on external insulation <\/td>\n<\/tr>\n | ||||||
| 238<\/td>\n | 5.1.5 Probability of disruptive discharge of insulation <\/td>\n<\/tr>\n | ||||||
| 239<\/td>\n | 5.2 Performance criterion <\/td>\n<\/tr>\n | ||||||
| 240<\/td>\n | 5.3 Insulation co-ordination procedures 5.3.1 General <\/td>\n<\/tr>\n | ||||||
| 241<\/td>\n | 5.3.2 Insulation co-ordination procedures for continuous (power-frequency) voltage and temporary overvoltage 5.3.3 Insulation co-ordination procedures for slow-front overvoltages <\/td>\n<\/tr>\n | ||||||
| 242<\/td>\n | Figure 4 \u2013 Distributive discharge probability of self-restoring insulation described on a linear scale Figure 5 \u2013 Disruptive discharge probability of self-restoring insulation described on a Gaussian scale <\/td>\n<\/tr>\n | ||||||
| 243<\/td>\n | Figure 6 \u2013 Evaluation of deterministic co-ordination factor Kcd <\/td>\n<\/tr>\n | ||||||
| 244<\/td>\n | Figure 7 \u2013 Evaluation of the risk of failure <\/td>\n<\/tr>\n | ||||||
| 246<\/td>\n | 5.3.4 Insulation co-ordination procedures for fast-front overvoltages Figure 8 \u2013 Risk of failure of external insulation for slow-front overvoltages as a function of the statistical co-ordination factor Kcs <\/td>\n<\/tr>\n | ||||||
| 247<\/td>\n | 6 Required withstand voltage 6.1 General remarks 6.2 Atmospheric correction 6.2.1 General remarks 6.2.2 Altitude correction <\/td>\n<\/tr>\n | ||||||
| 248<\/td>\n | Figure 9 \u2013 Dependence of exponent m on the co-ordination switching impulse withstand voltage <\/td>\n<\/tr>\n | ||||||
| 249<\/td>\n | 6.3 Safety factors 6.3.1 General 6.3.2 Ageing 6.3.3 Production and assembly dispersion 6.3.4 Inaccuracy of the withstand voltage <\/td>\n<\/tr>\n | ||||||
| 250<\/td>\n | 6.3.5 Recommended safety factors (Ks) 7 Standard withstand voltage and testing procedures 7.1 General remarks 7.1.1 Overview 7.1.2 Standard switching impulse withstand voltage <\/td>\n<\/tr>\n | ||||||
| 251<\/td>\n | 7.1.3 Standard lightning impulse withstand voltage 7.2 Test conversion factors 7.2.1 Range I <\/td>\n<\/tr>\n | ||||||
| 252<\/td>\n | 7.2.2 Range II 7.3 Determination of insulation withstand by type tests 7.3.1 Test procedure dependency upon insulation type Tables Table 1 \u2013 Test conversion factors for range I, to convert required SIWV to SDWV and LIWV Table 2 \u2013 Test conversion factors for range II to convert required SDWV to SIWV <\/td>\n<\/tr>\n | ||||||
| 253<\/td>\n | 7.3.2 Non-self-restoring insulation 7.3.3 Self-restoring insulation 7.3.4 Mixed insulation <\/td>\n<\/tr>\n | ||||||
| 254<\/td>\n | 7.3.5 Limitations of the test procedures Figure 10 \u2013 Probability P of an equipment to pass the test dependent onthe difference K between the actual and the rated impulse withstand voltage Table 3 \u2013 Selectivity of test procedures B and C of IEC 60060-1 <\/td>\n<\/tr>\n | ||||||
| 255<\/td>\n | 7.3.6 Selection of the type test procedures 7.3.7 Selection of the type test voltages <\/td>\n<\/tr>\n | ||||||
| 256<\/td>\n | 8 Special considerations for overhead lines 8.1 General remarks 8.2 Insulation co-ordination for operating voltages and temporary overvoltages 8.3 Insulation co-ordination for slow-front overvoltages 8.3.1 General <\/td>\n<\/tr>\n | ||||||
| 257<\/td>\n | 8.3.2 Earth-fault overvoltages 8.3.3 Energization and re-energization overvoltages 8.4 Insulation co-ordination for lightning overvoltages 8.4.1 General 8.4.2 Distribution lines <\/td>\n<\/tr>\n | ||||||
| 258<\/td>\n | 8.4.3 Transmission lines 9 Special considerations for substations 9.1 General remarks 9.1.1 Overview 9.1.2 Operating voltage 9.1.3 Temporary overvoltage Figure 11 \u2013 Example of a schematic substation layout used for the overvoltage stress location <\/td>\n<\/tr>\n | ||||||
| 259<\/td>\n | 9.1.4 Slow-front overvoltages 9.1.5 Fast-front overvoltages 9.2 Insulation co-ordination for overvoltages 9.2.1 Substations in distribution systems with Um up to 36 kV in range I <\/td>\n<\/tr>\n | ||||||
| 260<\/td>\n | 9.2.2 Substations in transmission systems with Um between 52,5 kV and 245 kV in range I <\/td>\n<\/tr>\n | ||||||
| 261<\/td>\n | 9.2.3 Substations in transmission systems in range II <\/td>\n<\/tr>\n | ||||||
| 262<\/td>\n | Annexes Annex A (informative) Determination of temporary overvoltages due to earth faults <\/td>\n<\/tr>\n | ||||||
| 263<\/td>\n | Figure A.1 \u2013 Earth fault factor k on a base of X0\/X1 for R1\/X1 = R = 0 Figure A.2 \u2013 Relationship between R0\/X1 and X0\/X1 for constant values of earth fault factor k where R1 = 0 <\/td>\n<\/tr>\n | ||||||
| 264<\/td>\n | Figure A.3 \u2013 Relationship between R0\/X1 and X0\/X1 for constant values of earth fault factor k where R1 = 0,5 X1 Figure A.4 \u2013 Relationship between R0\/X1 and X0\/X1 for constant values of earth fault factor k where R1 = X1 <\/td>\n<\/tr>\n | ||||||
| 265<\/td>\n | Figure A.5 \u2013 Relationship between R0\/X1 and X0\/X1 for constant values of earth fault factor k where R1 = 2X1 <\/td>\n<\/tr>\n | ||||||
| 266<\/td>\n | Annex B (informative) Weibull probability distributions B.1 General remarks <\/td>\n<\/tr>\n | ||||||
| 267<\/td>\n | B.2 Disruptive discharge probability of external insulation <\/td>\n<\/tr>\n | ||||||
| 268<\/td>\n | Table B.1 \u2013 Breakdown voltage versus cumulative flashover probability \u2013Single insulation and 100 parallel insulations <\/td>\n<\/tr>\n | ||||||
| 269<\/td>\n | B.3 Cumulative frequency distribution of overvoltages <\/td>\n<\/tr>\n | ||||||
| 271<\/td>\n | Figure B.1 \u2013 Conversion chart for the reduction of the withstand voltage due to placing insulation configurations in parallel <\/td>\n<\/tr>\n | ||||||
| 272<\/td>\n | Annex C (informative) Determination of the representative slow-front overvoltage due to line energization and re-energization C.1 General remarks C.2 Probability distribution of the representative amplitude of the prospective overvoltage phase-to-earth C.3 Probability distribution of the representative amplitude of the prospective overvoltage phase-to-phase <\/td>\n<\/tr>\n | ||||||
| 274<\/td>\n | C.4 Insulation characteristic <\/td>\n<\/tr>\n | ||||||
| 276<\/td>\n | C.5 Numerical example <\/td>\n<\/tr>\n | ||||||
| 278<\/td>\n | Figure C.1 \u2013 Example for bivariate phase-to-phase overvoltage curves with constant probability density and tangents giving the relevant 2 % values <\/td>\n<\/tr>\n | ||||||
| 279<\/td>\n | Figure C.2 \u2013 Principle of the determination of the representative phase-to-phase overvoltage Upre <\/td>\n<\/tr>\n | ||||||
| 280<\/td>\n | Figure C.3 \u2013 Schematic phase-phase-earth insulation configuration Figure C.4 \u2013 Description of the 50 % switching impulse flashover voltage ofa phase-phase-earth insulation <\/td>\n<\/tr>\n | ||||||
| 281<\/td>\n | Figure C.5 \u2013 Inclination angle of the phase-to-phase insulation characteristicin range “b” dependent on the ratio of the phase-phase clearance Dto the height Ht above earth <\/td>\n<\/tr>\n | ||||||
| 282<\/td>\n | Annex D (informative) Transferred overvoltages in transformers D.1 General remarks <\/td>\n<\/tr>\n | ||||||
| 283<\/td>\n | D.2 Transferred temporary overvoltages D.3 Capacitively transferred surges <\/td>\n<\/tr>\n | ||||||
| 285<\/td>\n | D.4 Inductively transferred surges <\/td>\n<\/tr>\n | ||||||
| 287<\/td>\n | Figure D.1 \u2013 Distributed capacitances of the windings of a transformer and the equivalent circuit describing the windings <\/td>\n<\/tr>\n | ||||||
| 288<\/td>\n | Figure D.2 \u2013 Values of factor J describing the effect of the winding connections on the inductive surge transference <\/td>\n<\/tr>\n | ||||||
| 289<\/td>\n | Annex E (informative) Lightning overvoltages E.1 General remarks E.2 Determination of the limit distance (Xp) E.2.1 Protection with arresters in the substation <\/td>\n<\/tr>\n | ||||||
| 290<\/td>\n | E.2.2 Self-protection of substation Table E.1 \u2013 Corona damping constant Kco <\/td>\n<\/tr>\n | ||||||
| 291<\/td>\n | E.3 Estimation of the representative lightning overvoltage amplitude E.3.1 General E.3.2 Shielding penetration <\/td>\n<\/tr>\n | ||||||
| 292<\/td>\n | E.3.3 Back flashovers <\/td>\n<\/tr>\n | ||||||
| 294<\/td>\n | E.4 Simplified method <\/td>\n<\/tr>\n | ||||||
| 295<\/td>\n | Table E.2 \u2013 Factor A for various overhead lines <\/td>\n<\/tr>\n | ||||||
| 296<\/td>\n | E.5 Assumed maximum value of the representative lightning overvoltage <\/td>\n<\/tr>\n | ||||||
| 297<\/td>\n | Annex F (informative) Calculation of air gap breakdown strength from experimental data F.1 General F.2 Insulation response to power-frequency voltages <\/td>\n<\/tr>\n | ||||||
| 298<\/td>\n | F.3 Insulation response to slow-front overvoltages <\/td>\n<\/tr>\n | ||||||
| 299<\/td>\n | F.4 Insulation response to fast-front overvoltages <\/td>\n<\/tr>\n | ||||||
| 301<\/td>\n | Table F.1 \u2013 Typical gap factors K for switching impulse breakdown phase-to-earth (according to [1] and [4]) <\/td>\n<\/tr>\n | ||||||
| 302<\/td>\n | Table F.2 \u2013 Gap factors for typical phase-to-phase geometries <\/td>\n<\/tr>\n | ||||||
| 303<\/td>\n | Annex G (informative) Examples of insulation co-ordination procedure G.1 Overview G.2 Numerical example for a system in range I (with nominal voltage of 230 kV) G.2.1 General <\/td>\n<\/tr>\n | ||||||
| 304<\/td>\n | G.2.2 Part 1: no special operating conditions <\/td>\n<\/tr>\n | ||||||
| 310<\/td>\n | Table G.1 \u2013 Summary of minimum required withstand voltages obtained for the example shown in G.2.2 <\/td>\n<\/tr>\n | ||||||
| 311<\/td>\n | G.2.3 Part 2: influence of capacitor switching at station 2 <\/td>\n<\/tr>\n | ||||||
| 312<\/td>\n | Table G.2 \u2013 Summary of required withstand voltages obtained for the example shown in G.2.3 <\/td>\n<\/tr>\n | ||||||
| 313<\/td>\n | G.2.4 Part 3: flow charts related to the example of Clause G.2 <\/td>\n<\/tr>\n | ||||||
| 318<\/td>\n | G.3 Numerical example for a system in range II (with nominal voltage of 735 kV) G.3.1 General G.3.2 Step 1: determination of the representative overvoltages \u2013 values of Urp <\/td>\n<\/tr>\n | ||||||
| 319<\/td>\n | G.3.3 Step 2: determination of the co-ordination withstand voltages \u2013 values of Ucw <\/td>\n<\/tr>\n | ||||||
| 320<\/td>\n | G.3.4 Step 3: determination of the required withstand voltages \u2013 values of Urw <\/td>\n<\/tr>\n | ||||||
| 321<\/td>\n | G.3.5 Step 4: conversion to switching impulse withstand voltages (SIWV) G.3.6 Step 5: selection of standard insulation levels <\/td>\n<\/tr>\n | ||||||
| 322<\/td>\n | G.3.7 Considerations relative to phase-to-phase insulation co-ordination <\/td>\n<\/tr>\n | ||||||
| 323<\/td>\n | G.3.8 Phase-to-earth clearances G.3.9 Phase-to-phase clearances <\/td>\n<\/tr>\n | ||||||
| 324<\/td>\n | G.4 Numerical example for substations in distribution systems with Um up to 36 kV in range I G.4.1 General G.4.2 Step 1: determination of the representative overvoltages \u2013 values of Urp <\/td>\n<\/tr>\n | ||||||
| 325<\/td>\n | G.4.3 Step 2: determination of the co-ordination withstand voltages \u2013 values of Ucw <\/td>\n<\/tr>\n | ||||||
| 326<\/td>\n | G.4.4 Step 3: determination of required withstand voltages \u2013 values of Urw <\/td>\n<\/tr>\n | ||||||
| 327<\/td>\n | G.4.5 Step 4: conversion to standard short-duration power-frequency and lightning impulse withstand voltages G.4.6 Step 5: selection of standard withstand voltages <\/td>\n<\/tr>\n | ||||||
| 328<\/td>\n | G.4.7 Summary of insulation co-ordination procedure for the example of Clause G.4 <\/td>\n<\/tr>\n | ||||||
| 329<\/td>\n | Table G.3 \u2013 Values related to the insulation co-ordination procedure for the example in G.4 <\/td>\n<\/tr>\n | ||||||
| 330<\/td>\n | Annex H (informative)Atmospheric correction \u2013 Altitude correction H.1 General principles H.1.1 Atmospheric correction in standard tests <\/td>\n<\/tr>\n | ||||||
| 331<\/td>\n | H.1.2 Task of atmospheric correction in insulation co-ordination Figure H.1 \u2013 Principle of the atmospheric correction during test of a specified insulation level according to the procedure of IEC 60060-1 <\/td>\n<\/tr>\n | ||||||
| 332<\/td>\n | Figure H.2 \u2013 Principal task of the atmospheric correctionin insulation co-ordination according to IEC 60071-1 <\/td>\n<\/tr>\n | ||||||
| 333<\/td>\n | H.2 Atmospheric correction in insulation co-ordination H.2.1 Factors for atmospheric correction H.2.2 General characteristics for moderate climates <\/td>\n<\/tr>\n | ||||||
| 334<\/td>\n | H.2.3 Special atmospheric conditions Figure H.3 \u2013 Comparison of atmospheric correction \u03b4 \u00d7 kh with relative air pressure p\/p0 for various weather stations around the world <\/td>\n<\/tr>\n | ||||||
| 335<\/td>\n | H.2.4 Altitude dependency of air pressure <\/td>\n<\/tr>\n | ||||||
| 336<\/td>\n | H.3 Altitude correction H.3.1 Definition of the altitude correction factor Figure H.4 \u2013 Deviation of simplified pressure calculation by exponential function in this document from the temperature dependent pressure calculation of ISO 2533 <\/td>\n<\/tr>\n | ||||||
| 337<\/td>\n | H.3.2 Principle of altitude correction Figure H.5 \u2013 Principle of altitude correction: decreasing withstand voltage U10 of equipment with increasing altitude <\/td>\n<\/tr>\n | ||||||
| 338<\/td>\n | H.3.3 Standard equipment operating at altitudes up to 1 000 m H.3.4 Equipment operating at altitudes above 1 000 m <\/td>\n<\/tr>\n | ||||||
| 339<\/td>\n | H.4 Selection of the exponent m H.4.1 General H.4.2 Derivation of exponent m for switching impulse voltage <\/td>\n<\/tr>\n | ||||||
| 341<\/td>\n | Figure H.6 \u2013 Sets of m-curves for standard switching impulse voltage including the variations in altitude for each gap factor <\/td>\n<\/tr>\n | ||||||
| 342<\/td>\n | H.4.3 Derivation of exponent m for critical switching impulse voltage Figure H.7 \u2013 Exponent m for standard switching impulse voltage for selected gap factors covering altitudes up to 4 000 m <\/td>\n<\/tr>\n | ||||||
| 343<\/td>\n | Figure H.8 \u2013 Sets of m-curves for critical switching impulse voltage including the variations in altitude for each gap factor Figure H.9 \u2013 Exponent m for critical switching impulse voltage for selected gap factors covering altitudes up to 4 000 m <\/td>\n<\/tr>\n | ||||||
| 344<\/td>\n | Figure H.10 \u2013 Accordance of m-curves from Figure 9 with determination ofexponent m by means of critical switching impulse voltage for selected gap factors and altitudes Table H.1 \u2013 Comparison of functional expressions of Figure 9 with the selected parameters from the derivation of m-curves with critical switching impulse <\/td>\n<\/tr>\n | ||||||
| 345<\/td>\n | Annex I (informative) Evaluation method of non-standard lightning overvoltage shape for representative voltages and overvoltages I.1 General remarks I.2 Lightning overvoltage shape I.3 Evaluation method for GIS I.3.1 Experiments <\/td>\n<\/tr>\n | ||||||
| 346<\/td>\n | I.3.2 Evaluation of overvoltage shape I.4 Evaluation method for transformer I.4.1 Experiments I.4.2 Evaluation of overvoltage shape <\/td>\n<\/tr>\n | ||||||
| 348<\/td>\n | Figure I.1 \u2013 Examples of lightning overvoltage shapes <\/td>\n<\/tr>\n | ||||||
| 349<\/td>\n | Figure I.2 \u2013 Example of insulation characteristics with respect to lightning overvoltages of the SF6 gas gap (Shape E) Figure I.3 \u2013 Calculation of duration time Td Table I.1 \u2013 Evaluation of the lightning overvoltage in the GIS of UHV system <\/td>\n<\/tr>\n | ||||||
| 350<\/td>\n | Figure I.4 \u2013 Shape evaluation flow for GIS and transformer <\/td>\n<\/tr>\n | ||||||
| 351<\/td>\n | Figure I.5 \u2013 Application to GIS lightning overvoltage Figure I.6 \u2013 Example of insulation characteristics with respect to lightning overvoltage of the turn-to-turn insulation (Shape C) <\/td>\n<\/tr>\n | ||||||
| 352<\/td>\n | Figure I.7 \u2013 Application to transformer lightning overvoltage Table I.2 \u2013 Evaluation of lightning overvoltage in the transformer of 500 kV system <\/td>\n<\/tr>\n | ||||||
| 353<\/td>\n | Annex J (informative) Insulation co-ordination for very-fast-front overvoltages in UHV substations J.1 General J.2 Influence of disconnector design <\/td>\n<\/tr>\n | ||||||
| 354<\/td>\n | J.3 Insulation co-ordination for VFFO <\/td>\n<\/tr>\n | ||||||
| 355<\/td>\n | Figure J.1 \u2013 Insulation co-ordination for very-fast-front overvoltages <\/td>\n<\/tr>\n | ||||||
| 356<\/td>\n | Bibliography <\/td>\n<\/tr>\n<\/table>\n","protected":false},"excerpt":{"rendered":" Tracked Changes. Insulation co-ordination – Application guidelines<\/b><\/p>\n |