Power Network Application Trainer
– Earthing / Grounding network impedance measurement
37
2
Earthing and Grounding resistance measurements .......................................... 42
2.1
Basic theory about earthing ........................................................................................................ 42
2.2
Specific earth resistance measurements [ρ] ............................................................................... 44
2.2.1
Wenner method measurement .......................................................................................... 46
2.2.2
Schlumberger method measurement ................................................................................. 46
2.3
Earth resistance measurement [Ze and Re] ................................................................................ 48
2.3.1
Functionality and placing of test probes ............................................................................. 48
2.3.1.1 Straight-line placement ................................................................................................... 49
2.3.1.2 Equilateral placement ..................................................................................................... 51
2.3.1.3 Test probe resistances .................................................................................................... 51
2.3.2
Earth resistance measurements method ............................................................................ 53
2.3.2.1 2–pole measurement – single frequency and sweep mode up to 15 kHz ...................... 57
2.3.2.2 3–pole measurement – single frequency and sweep mode up to15 kHz....................... 57
2.3.2.3 4–pole measurement – single frequency and sweep mode up to 15 kHz ...................... 58
2.3.2.4 Selective (Iron Clamp) Measurement – single frequency and sweep mode up to
1.5 kHz .............................................................................................................................. 59
2.3.2.5 2 Clamps Measurement – single frequency and sweep mode up to 329 Hz .................. 59
2.3.2.6 HF-Earth Resistance (25 kHz) measurement .................................................................. 60
2.3.2.7 Selective (Flex Clamps 1 - 4) measurement – single frequency and sweep mode
up to 1.5 kHz ..................................................................................................................... 61
2.3.2.8 Passive (Flex Clamps) Measurement .............................................................................. 62
2.4
Pylon Ground Wire Test (PGWT) ................................................................................................ 64
2.5
Impulse impedance [Zp] ............................................................................................................. 65
3
Earth Potential ....................................................................................................... 69
3.1
Ground Potential Rise, Step Voltage, Contact Voltage ............................................................... 70
3.1.1
Ground Potential Rise ......................................................................................................... 70
3.1.2
Step & contact voltage measurement ................................................................................ 72
4
Exercises on MI 3298 P1 training module ........................................................... 75
4.1
Earth resistance measurement exercises ................................................................................... 81
4.1.1
3-Pole and 4-Pole earth resistance measuring method ..................................................... 81
4.1.1.1 Measurement with MI 3290 Earth Analyzer ................................................................... 81
4.1.1.1.1
3 Pole measuring method ........................................................................................... 81
4.1.1.1.2
4 Pole measuring method ........................................................................................... 84
4.1.1.2 Measurement with MI 3123 SmartTEC (Earth/Clamp) meter ........................................ 87
4.1.1.3 Measurement with MI 3295S Step Contact Voltage Measuring System ........................ 89
4.1.2
4 Pole measuring method – simulated different test object state ..................................... 92
4.1.2.1 Simulation of inductive earth character, regular pylon foot’s condition ....................... 92
4.1.2.2 Simulation of resistance earth character and broken pylon’s foot connection ............. 94
4.1.2.3 Simulation of resistance/inductive earth character, regular foot’s condition and
simulated Ground Wire connection ................................................................................ 95
4.1.3
S – Flex measuring method by using one Flex-clamp ......................................................... 98
4.1.3.1 S – Flex measuring method by using one Flex- clamp with simulated regular pylon’s
foot condition and resistance earth character ............................................................................... 98
4.1.3.2 S – Flex measuring method by using one Flex-clamp with simulated broken foot
resistance and resistive earthing type .......................................................................................... 101
4.1.3.3 S – Flex measuring method by using one Flex-clamp - regular foot resistance/ - resistive
earthing type - simulated ground wire connection ...................................................................... 104
4.1.3.4 S – Flex measuring method by using one Flex-clamp - regular foot resistance/inductive
earthing type/simulated ground wire connection ........................................................................ 106
4.1.3.5 S – Flex measuring method by using one Flex-clamp with simulated regular pylon’s foot
condition and resistance earth character ..................................................................................... 108
Summary of Contents for MI 3298
Page 55: ...Power Network Application Trainer Earthing Grounding network impedance measurement 55 ...
Page 56: ...Power Network Application Trainer Earthing Grounding network impedance measurement 56 ...
Page 124: ...Power Network Application Trainer Earthing Grounding network impedance measurement 124 ...
Page 228: ...MI 3290 Earth Analyser 228 ...
Page 229: ...MI 3280 Digital Transformer Analyser 229 ...
Page 230: ...MI 3280 Digital Transformer Analyser 230 ...
Page 231: ...MI 3250 MicroOhm 10A 231 ...
Page 232: ...MI 3205 TeraOhmXA 5kV 232 ...