Page 299 - Practical Power System and Protective Relays Commissioning

Protection Relays Settings Chapter | 19 293

Z 3 reverse 5 0:25 3 Z P line AB
5 0:25 3 18:287 +82:231
5 4:571 + 82:231 Ω

5 4:571 Ω
The earth fault residual compensation factor is calculated as:

Z 10 2 Z 1P
K 0 5
3Z 1P
Z 0 line AB 5 0:25 1 J 0:95Þ 3 60
ð
Z 0 line AB 5 15 1 57J 5 58:94 + 75:25 1
58:94+75:25 2 18:287+82:231
K 0 5
3 3 18:287+82:231
15 1 J56:99 2 2:472 2 J18:12
5
54:861+82:231
12:528 1 J38:87
5
54:861+82:231
40:839+72:135
5
54:861+82:231

K 0 5 0.7444 + 10.096
K 0 5 0.744
The setting secondary values are:
CTratio
5 14:629 3
Z 1 Reach
PTratio
800
5 14:629 3
2200
5 14:629 3 0:363
5 5:319Ω; t 1 instantaneous

5 25:965 3 0:363
Z 2 Reach
5 9:425 Ω ; t 2 5 500 ms
5 44:1945 3 0:363
Z 3 Reach
5 16:042 Ω ; t 3 5 900 ms
5 4:571 3 0:363
Z 3 Reverse
5 1:659 Ω
Power Swing Blocking Settings