Various clearances required to be maintained as per Indian Electricity Rules and Code of practice etc. during construction of a transmission line are given at appropriate places in various chapters. However, for convenience, the various clearances required to be maintained in the construction of a transmission line at a glance are given in the following table:
TABLE : 24.1
| Sr. No. |
Particulars |
Units |
Clearance required to be maintained for |
| 132 KV |
220 KV |
400 KV |
| 1. |
Live Metal Clearance |
| (a) Suspension Towers |
mm |
1525(0°- 25° swing)
1075(25° - 45° swing) |
2130 (0° - 20°)
1675 (20° -50") |
2600 (V - string) |
| (b) Tension towers |
mm |
1525 |
2130 |
2600 |
| 2. |
Ground Clearance |
m |
6.1 |
7.0 |
8.84 |
| 3. |
Mid Span Clearance |
in |
6.1 |
8.5 |
9.0 |
| 4. |
Phase to Phase Clearance |
mm |
3900 |
5130 |
7000 |
| 5. |
Maximum Shielding Angle |
30° |
30° |
30° |
20° |
| 6. |
Power Line Crossing Clearance between Lines |
m |
3.05 (from other lines of 11 KV to 132KV) |
4.58 (from other lines of 11 KV to 220 KV) |
6.10 (front other lines of 11-KV to 400KV) |
| 7. |
Clearance Between lines and Tramway Crossing |
m |
3.05 |
3.05 |
3.05 |
| 8. |
Clearance from Railway^ Track |
m |
14.60 |
15.40 |
17.90 |
| 9. |
Prescribed Corridor for Forest clearance etc. |
m |
27.60 |
35.00 |
52.00 |
| 10. |
Minimum Clearances from Trees |
m |
4.0 |
4.6 |
5.5 |
| 11. |
Clearance over Rivers from HFL |
| (i) Non Navigable River |
m |
6.1 |
7.00 |
8.84 |
| (ii) Navigable River |
m |
To be maintained in relation to tallest mast in consolation with navigation authorities |
| 12. |
Clearances from Buildings |
| (a) Horizontal |
m |
2.744 |
3.659 |
5.489 |
| (b) Vertical |
m |
4.573 |
5.488 |
7.318 |
| 13. |
Clearance over Telecommunication lines |
m |
2.745 |
3.050 |
4.880 |