1 - AS 1675-1986 CURRENT TRANSFORMERS - MEASUREMENT AND PROTECTION
4 - PREFACE
5 - CONTENTS
7 - SECTION 1. SCOPE AND GENERAL REQUIREMENTS
7 - 1.1 SCOPE.
7 - 1.2 APPLICATION.
7 - 1.3 REFERENCED DOCUMENTS.
7 - 1.4 DEFINITIONS.
7 - 1.4.1 General.
7 - 1.4.2 Definitions relating to construction.
9 - 1.4.3 Definitions relating to performance.
10 - 1.4.4 Definitions relating to service conditions of a three-phase system.
10 - 1.5 SERVICE CONDITIONS
10 - 1.6 RATED FREQUENCY.
11 - 1.7 RATED INSULATION LEVEL (RIL)
11 - 1.7.1 Selection.
11 - 1.7.2 Method of expression.
11 - 1.8 RATED CURRENTS.
11 - 1.8.1 Rated primary current.
11 - 1.8.2 Rated secondary current.
11 - 1.8.3 Thermal limit current.
11 - 1.8.4 Rated short-time current.
11 - 1.9 RATED SHORT-TIME
12 - 1.10 TEMPERATURE RISE
12 - 1.10.1 General.
12 - 1.10.2 Temperature rise of windings.
12 - 1.10.3 Temperature rise of oil.
12 - 1.10.4 Temperature rise of core or other metallic parts
12 - 1.11 SHORT-TIME CURRENT WITHSTAND
12 - 1.12 TERMINAL MARKINGS.
12 - 1.12.1 General.
12 - 1.12.2 Marking principles.
13 - 1.12.3 Series-parallel connections.
13 - 1.12.4 Test-Tap terminals
14 - 1.13 ROUTINE TESTS.
14 - 1.13.1 General.
14 - 1.13.2 Verification of terminal markings.
14 - 1.13.3 Arrangement of the CT for voltage withstand tests
14 - 1.13.4 High voltage testing techniques.
14 - 1.13.5 Voltage withstand: secondary winding(s) to earth
14 - 1.13.6 Voltage withstand: between primary windings or between sections of a primary windings
14 - 1.13.7 Voltage withstand: primary winding(s) to earth
14 - 1.13. 8 Voltage withstand: between turns of the secondary winding.
15 - 1.13.9 Subsequent dielectric tests.
15 - 1.13.10 Partial discharge test.
15 - 1.13.11 Measurement of dielectric dissipation factor (tangent delta) of a CT having capacitively-graded insulation
15 - 1.14 TYPE TESTS.
15 - 1.14.1 General.
15 - 1.14.2 High-voltage power-frequency wet withstand test on outdoor CTs
16 - 1.14.3 Impulse-voltage withstand test on primary insulation
16 - 1.14.4 Temperature rise test.
16 - 1.14.5 Short-time current withstand test.
17 - 1.15 SPECIAL TYPE TESTS.
17 - 1.15.1 Radio influence voltage (RIV) test.
17 - 1.15.2 Thermal stability test.
17 - 1.16 COMMISSIONING TESTS.
17 - 1.17 RATING PLATE MARKINGS.
18 - SECTION 2. SPECIFIC REQUIREMENTS FOR MEASUREMENT CURRENT TRANSFORMERS
18 - 2.1 SCOPE OF SECTION.
18 - 2.2 APPLICATION.
18 - 2.3 CLASSIFICATION OF MEASUREMENT CTs
18 - 2.4 CLASS M CTs.
18 - 2.4.1 Designation.
18 - 2.4.2 Accuracy classification.
18 - 2.4.3 Current errors and phase errors.
18 - 2.5 CLASS ME CTs.
18 - 2.5.1 Designation.
18 - 2.5.2 Accuracy classification.
18 - 2.5.3 Rated accuracy limit factor.
18 - 2.5.4 Current errors and phase errors.
18 - 2.6 EFFECTIVE DEMAGNETIZATION.
20 - 2.7 RATED BURDENS AND RATED OUTPUTS.
20 - 2.8 DETERMINATION OF ERRORS.
20 - 2.8.1 Type tests.
20 - 2.8.2 Routine tests.
20 - 2.9 RATING PLATE MARKINGS.
20 - 2.9.1 Location.
20 - 2.9.2 Information to be marked.
21 - SECTION 3. SPECIFIC REQUIREMENTS FOR PROTECTION CURRENT TRANSFORMERS
21 - 3.1 SCOPE OF SECTION.
21 - 3.2 APPLICATION.
21 - 3.3 CLASSIFICATION OF PROTECTION CTs.
21 - 3.4 CLASS P CTs.
21 - 3.4.1 Designation.
21 - 3.4.2 Rated composite error.
21 - 3.4.3 Rated secondary reference voltage.
21 - 3.4.4 Rated accuracy limit factor.
21 - 3.4.5 Composite error (see Appendix J).
21 - 3.4.6 Current error.
22 - 3.5 CLASS PL CTs.
22 - 3.5.1 Designation.
22 - 3.5.2 Alternative method of specification.
22 - 3.5.3 Turns ratio
22 - 3.5.4 Ratio of the composite error measured indirectly to the composite error measured directly
22 - 3.5.5 Knee-point voltage
22 - 3.5.6 Secondary exciting current.
22 - 3.5.7 Secondary winding resistance.
23 - 3.6 CLASS PS CTs.
23 - 3.6.1 Designation.
23 - 3.6.2 Specification.
23 - 3.7 DETERMINATION OF COMPLIANCE WITH THIS SECTION
23 - 3.8 RATING PLATE MARKINGS.
23 - 3.8.1 Location.
23 - 3.8.2 Information to be marked.
24 - APPENDIX A - INFORMATION TO BE SUPPLIED WITH ENQUIRY AND ORDER
25 - APPENDIX B - GUIDANCE IN THE APPLICATION OF CURRENT TRANSFORMERS
25 - B1 MEASUREMENT CURRENT TRANSFORMERS.
25 - B1.1 Rated burden.
25 - B1.2 Accuracy class.
25 - B2 PROTECTION CURRENT TRANSFORMERS.
25 - B2.1 General.
25 - B2.2 Rated transformation ratio.
26 - B2.3 Transient performance, transient factor and maximum operating level.
27 - B2.4 Classification of current transformers.
27 - B2.5 Correlation of transformer class, maximum operating level, and categories of protection.
29 - B3 DUAL-PURPOSE CURRENT TRANSFORMERS
29 - B4 ELECTROSTATICALLY-SCREENED CURRENT TRANSFORMERS.
29 - B4.1 General.
29 - B4.2 Electrostatic effects.
30 - B5 ELECTROMAGNETICALLY- SHIELDED CURRENT TRANSFORMERS
30 - B5.1 General.
30 - B5.2 Electromagnetic effects.
31 - B6 MULTIPLE-RATIO CURRENT TRANSFORMERS.
31 - B7 OPEN-CIRCUIT SECONDARY.
33 - APPENDIX C - SERVICE CONDITIONS
33 - C1 AMBIENT TEMPERATURE.
33 - C2 LOCAL ATMOSPHERIC AND CLIMATIC CONDITIONS.
34 - APPENDIX D - SHORT-TIME CURRENT RATING OF CURRENT TRANSFORMERS
37 - APPENDIX E - TEMPERATURE MEASUREMENTS
37 - E1 INTRODUCTION.
37 - E2 RECOGNIZED METHODS OF MEASURING TEMPERATURE.
37 - E3 THERMOMETER METHOD.
37 - E4 THERMOCOUPLE METHOD.
37 - E5 SELF-RESISTANCE METHOD.
38 - E6 MEASUREMENT OF TEST CONNECTIONS.
39 - APPENDIX F - CURRENT TRANSFORMER TEST TAPS
40 - APPENDIX G - METHOD OF TEST FOR RADIO INFLUENCE VOLTAGE (RIV)
40 - G1 ARRANGEMENT.
40 - G2 TEST EQUIPMENT.
40 - G3 TEST PROCEDURE.
42 - APPENDIX H - EQUIVALENCE OF IEC CLASS P CTs AND AUSTRALIAN CLASS P CTs
44 - APPENDIX J - COMPOSITE ERROR
44 - J1 GENERAL.
44 - J2 EFFECT OF NON-LINEAR IMPEDANCE
45 - J3 ELECTROMAGNETIC COUPLING AND FLUX LEAKAGE.
45 - J4 INSULATION LEAKAGE CURRENTS.
45 - J5 INDIRECT MEASUREMENT OF COMPOSITE ERROR.
45 - J5.1 General.
45 - J5.2 Measurement at accuracy limit current.
46 - J6 DIRECT MEASUREMENT OF COMPOSITE ERROR.
46 - J6.1 General.
46 - J6.2 Alternative method of test.
48 - J7 TEST PRECAUTIONS.
49 - APPENDIX K - DETERMINATION OF TURNS RATIO
49 - K1 GENERAL.
49 - K2 FACTORS 1 AND 2.
50 - K3 FACTOR 3.
50 - K4 FACTOR 4.
50 - K5 NOTATION.
51 - APPENDIX L - NOTATION
52 - ANNEX - LIST OF REFERENCED DOCUMENTS
53 - INDEX