People either passing by or living close to power transmission lines in the national capital are facing an imminent threat to their lives. This warning has been sounded by Delhi power secretary Sukesh Kumar Jain, who in his letter to environment and forest secretary S.M. Ali said that live conductors of tower lines have reduced to a dangerous low near the transmission lines at many places, making it prone to system faults, fire and transient tripping.
“A large number of trees/ saplings have come up in the ROW/ underneath/ near these transmission lines. During storms and rainy season, tree branches reached the flashover zone of 4,00,000 Volts and 2,20,000 Volts line, making it vulnerable to faults and which can lead to major fire in the area besides disruption of (power) supply to a large part of the adjoining area,” Mr Jain said in the letter.
He pointed out that when proactive action is taken by the Delhi Transco Limited to trim or prune these branches to restrict their growth to maintain the safety clearance, notices are issued to the DTL by the forest department, saying that it is an offence to cut trees in Delhi. He said it has been observed that in many incidents, persons resting under trees were subjected to fault current of the level of 20,000 to 40,000 Amperes, got burnt and lost their lives.
Delhi Transco Limited is the electrical transmission utility of the Delhi government and is responsible for smooth operation and maintenance of the extra high voltage transmission network of the capital region. DTL has four 400 Kilovolt and 34 220 Kilovolt grid substations spread across various locations in Delhi. These grid sub-stations are interconnected with each other by way of EHV transmission lines and underground cable links. The extra high voltage network of DTL comprises about 248 circuit km of 400 KV and 580 circuit km of 220 KV overhead transmission lines. Most of these extra high voltage lines installed on transmission towers are running in the national capital region.
These lines had been laid after due clearances from the Central Electrical Authority and other government agencies to draw power from the Northern Grid and from Delhi’s own generating stations to cater to the load of Delhi way back in the era of the erstwhile Desu/ DVB. Mr Jain wrote: “A clear corridor/ right of way of 35 metres is essential for those 220 KV extra high voltage lines and of 40 metres for 400 lines to operate smoothly as laid down in the India Electricity Act. The minimum vertical and horizontal clearances from the live conductors (wires) of these tower lines are 5.4 metres and 3.7 metres for 220 KV.
