Documents/Reports
Clearance at a Glance
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 |