1 - SAA HB102-1997 COORDINATION OF POWER AND TELECOMMUNICATIONS - LOW FREQUENCY INDUCTION (LFI) APPLICATION GUIDE TO THE LFI CODE
4 - PREFACE
5 - CONTENTS
9 - SECTION 1 INTRODUCTION
10 - SECTION 2 MECHANISM OF LOW FREQUENCY INDUCTION AND CALCULATION OF INDUCED VOLTAGES
13 - SECTION 3 PROCEDURES FOR MAKING CALCULATIONS AND DETERMINING BEST ENGINEERING SOLUTION
13 - 3.1 Calculation Procedure
15 - 3.2 Selection of Appropriate Induced Voltage Limit
15 - 3.3 Some Factors Considered by the Electricity Utility in Selection of Power Line Categories
18 - SECTION 4 EVALUATION OF FACTORS FOR CALCULATING INDUCED LONGITUDINAL VOLTAGES
18 - 4.1 Earth Fault Currents
18 - 4.1.1 Factors Affecting Fault Currents
19 - 4.1.2 Calculations of Fault Currents
22 - 4.2 Mutual and Self Impedances
22 - 4.2.1 Formulas and Nomogram for Calculations
23 - 4.2.2 Selection of Earth Resistivity Values
24 - 4.3 Shielding Factors
24 - 4.3.1 Fundamental Principles
26 - 4.3.2 Shielding Factors Relating to Power Lines and Power Cables
27 - 4.3.3 Shielding Factors Relating to Telephone Lines
28 - 4.3.4 Shielding by Adjacent Conductors
28 - 4.3.5 Shielding by Cable Sheaths
28 - 4.3.6 Shielding by Magnetic Loading
29 - 4.3.7 Shielding by Multiple Telecommunication Cables
29 - 4.3.8 Shielding by Environmental Metallic Conductors
30 - 4.3.9 Shielding by Earthing Spare Cable Pairs
30 - 4.3.10 Latent Shielding
31 - 4.4 Overvoltage Protection by Gas-Filled Protectors
33 - 4.5 Length of Exposure and Separation
33 - 4.5.1 General
33 - 4.5.2 Zone of Exposure for which Calculations may not be Required
34 - 4.5.3 Examples Where Calculations are Required
34 - 4.5.4 Summation of Exposure Sections
35 - 4.5.5 General Case
39 - SECTION 5 EXAMPLE OF CALCULATION
39 - 5.1 Typical Case
39 - 5.2 Details
39 - 5.3 Preparation and Assumptions
40 - 5.4 A Method of Making Detailed Calculations
40 - 5.4.1 Calculation of Currents for a Fault in the Power Line
45 - 5.4.2 Length of Exposure
45 - 5.4.3 Separation
45 - 5.4.4 Earth Characteristics
45 - 5.4.5 Average Mutual Impedance
45 - 5.4.6 Calculation of Induced Voltage
45 - 5.4.7 Calculation of Shielding Factor
47 - 5.4.8 Resultant Induced Voltage
47 - 5.4.9 Summary
48 - 5.4.10 Calculation of Induced Voltages in the Protected Cable
52 - 5.4.11 Conclusion
55 - SECTION 6 FIELD TESTS AND MEASUREMENTS
55 - 6.1 General
55 - 6.2 Safety Precautions
56 - 6.3 Testing Procedures
56 - 6.4 Elements of the Testing Circuit
59 - 6.5 Interpretation of Results
59 - 6.6 Ancillary Tests
60 - 6.6.1 Evaluation of Soil Resistivity
61 - 6.6.2 Determining Shielding Factors
62 - 6.7 A Practical Example
62 - 6.7.1 Details
63 - 6.7.2 Objects of the Tests
63 - 6.7.3 Lay-out of the Plant
65 - 6.7.4 Test Methods
66 - 6.7.5 Test Results
66 - 6.7.6 Discussion and Summary of Results
69 - 6.7.7 Further Action
70 - 6.7.8 Conclusions
76 - SECTION 7 RECORD OF POWER EARTH FAULTS
77 - SECTION 8 REFERENCES
79 - APPENDIX 1 - SHIELDING FACTORS OF EARTHED CONDUCTORS IN THE PROXIMITY OF TELECOMMUNICATION CABLES
79 - APPENDIX 2 - SHEATH RESISTANCE VERSUS EXTERNAL DIAMETER OF TELECOMMUNICATION CABLES
80 - APPENDIX 3 - SHIELDING FACTOR VERSUS SHEATH RESISTANCE OF TELECOMMUNICATION CABLES
81 - APPENDIX 4 - CONVERSION CHART FOR SHEATH RESISTANCE AND CONDUCTANCE
82 - APPENDIX 5 - SHIELDING FACTORS FOR LEAD-SHEATH CABLES
83 - APPENDIX 6 - SHIELDING FACTORS FOR PLASTIC-JACKET, LEAD-SHEATH CABLES
84 - APPENDIX 7 - SHIELDING FACTORS FOR MOISTURE-BARRIER CABLES
85 - APPENDIX 8 - SHIELDING FACTOR VERSUS DISTURBING FIELD
85 - (a) for 20/0.64 mm ST cable
85 - (b) for 20/0.90 mm ST cable
86 - (c) for 28/0.64 mm ST cable
86 - (d) for 50/0.64 mm ST cable
87 - (e) for 70/0.64 mm ST cable
87 - (f) for 100/0.64 mm ST cable
88 - (g) for GI pipes
88 - APPENDIX 9 - RESISTANCE VALUES FOR CONDUCTORS OF STANDARD SIZES
89 - APPENDIX 10 - LATENT REDUCTION FACTOR
90 - APPENDIX 11 - JOINT COMMITTEE FOR THE CO-ORDINATION OF POWER AND TELECOMMUNICATIONS SYSTEMS FAULT DOCKET
91 - APPENDIX 12 - ADDRESSES OF STATE POWER COORDINATION CONTACTS
92 - APPENDIX 13 - INDUCED VOLTAGES DUE TO TEST FAULT CURRENTS
92 - 1 SIGNIFICANCE OF THE PHASE ANGLE BETWEEN THE STANDING VOLTAGE AND THE MEASURED VOLTAGE WHEN THE POWER LINE IS EXCITED
93 - 2 DETERMINATION OF INDUCED VOLTAGE DUE TO TEST FAULT CURRENT