The stringent law to prevent unnecessary felling of trees in the national Capital has become an obstacle to Delhi Power Department’s commitment to provide uninterrupted electricity supply to the city. The Environment and Forest Department of the Delhi Government recently issued notices to Delhi Transco limited (DTl) against trimming or pruning of tree branches, saying it was an offence to cut/prune trees in the Capital.
Following the notices, Delhi Power Secretary Sukesh Kumar Jain has sent a letter to Environment and Forest Secretary SM Ali pointing out that proactive action initiated by the DTl to trim the tree branches is to restrict their growth to prevent system faults, fire and transient tripping.
Saying that DTl is the electrical transmission utility of the Delhi Government and is responsible for the smooth operation and maintenance of the Extra High Voltage (EHV) transmission network of the Capital region, Jain has urged his counterpart in Forest Department to give permission for trimming of trees in the right-of-way (ROW)/ underneath/ near the Extra High Tension Transmission lines and electrical installations of DTl as and when approached by DTl.
“A large number of trees/ saplings have come up in the ROW/underneath/ near these transmission lines. During storm and rainy season, the tree branches have 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,” said the letter. It further said it has been observed that in many incidents persons resting under the shade of those trees who were subjected to fault current of the level of 20,000 to 40,000 Ampere got burnt and lost their lives.
Trimming/pruning of trees is to avoid any mishap to human life, properties of nearby residents and for maintaining uninterrupted power supply to the citizens of Delhi as such tripping do have potential to severely affect power supply to large areas, added the letter.
DTl has four 400 Kilovolt and 34 220 Kilovolt of 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 EHV network of DTl comprises about 248 circuit Km of 400 KV and 580 circuit Km of 220 KV overhead transmission lines. Most of these EHV 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.
Jain said, “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 as per the provisions of the Indian Electricity Rules, 1956, Clause-80 (1) (2) and 82 are 5.4 metre and 3.7 metre for 220 KV and 07 metre and 5.3 metre for 400 KV respectively besides the ground clearance of 07 metre for 220 KV and 8.8 metre for 440 KV and the same have reduced to a dangerous low level at many places near these transmission lines, making it prone to system faults, fire and transient tripping.”