Delhi Discoms saves the day

The combined efforts of Delhi Distribution, Transmission & Generation Companies and Northern Region Load Dispatch Centre saved Delhi from black out and Northern Grid from failure post one of the deadliest storms which hit Delhi on Friday, May 30, 2014. The storm (heavy rains, dust and thunderstorms) not only damaged power network but also claimed several lives across the city.

The intensity of the catastrophe could be gauged from the fact that before storm the total load of Delhi was 5200 MW and during the storm it gradually fell within a few minutes at the rate 200 MW per minute to 1200 MW. In TPDDL area, the load fell from 1350 MW to paltry 300 MW due to major failure in the transmission network which included Delhi Transco Limited's 400/220 KV network ring which is the power life line of Delhi connecting Dadri, Mandola, Bawana, Bamnauli and Narela. This was a perfect case of Northern Grid failure but the system survived due to combined efforts of Northern Region Load Dispatch Centre, Transmission, Distribution and Generation Companies.

"The crisis was averted due to effective disaster management system, contingency planning, inter-grid connectivity and running the network on emergency mode and coordination between the Northern Region Load Dispatch Centre, Transmission, Delhi Distribution & Generation Companies. It could have snowballed into the July 30&31, 2012 like situation, the biggest ever power failure in Indian history, three inter-state transmission networks collapsed together, plunging most of north India into darkness and disrupting the daily lives of over 600 million people, about 9% of the world population, or half of India's population, spread across 22 states in Northern , Eastern, and Northeast India.",  said Praveer Sinha, CEO & ED, TPDDL.

The severity of the storm on the power network was such that it resulted in tripping of 68 transmission lines in the Northern Grid. The load loss was at the rate of 200 MW per minute,  resulting in a northern grid load loss of about 8,000 MW, including 4000 MW in Delhi. TPDDL also lost 1050 MW during the storm. Before, the storm hit Delhi the power demand was around 5200 MW, during the storm at around 5 O'clock the power demand plummeted to 1200 MW, in just under 20 minutes.

The storm came from Hissar-Sonepat side first to hit the North and North-West Delhi part i.e. TPDDL's distribution Area before moving to other parts of the capital. Soon after the storm, TPDDL's Disaster Management Team took stock of the situation to understand the extent of damage and to restore the power on a war footing to its consumers. The work was monitored on a real time basis to speed up the relief and restoration work in coordination with its dedicated and committed ground staff. The top most priority of TPDDL was to restore power supply to emergency services like Delhi Metro, Hospitals, and Delhi Jal Board Pumping Stations etc. The power was restored to Delhi Metro, Railways,Delhi Jal Board pumping stations, critical load to hospitals, government offices etc. was connected within 2 hours. To manage the crisis TPDDL also roped in additional staff, various equipment like cranes, tower  wagons etc.to clear trees and debris from the network.

During the high speed storm over 1000 trees fell on the power linesacross North Delhi. The storm damaged DTL's 5 Towers on the 400/220 KV Bawana-Rohini line, 2 towers from DTL 400/220 KV Mandola-Gopalpur also suffered a major damaged. The TPDDL network suffered majorly because of falling of around 500 fully grown Eucalyptus trees damaging nearly 250 Low Tension/ High Tension electricity poles in its network spread across 510 Sq Km. These Eucalyptus trees are a huge hazard and when they fall on the power lines, they completely snap the power supply. Additionally, conductor (lines) were broken at several locations, hundreds of LT/HT ABC were broken at different locations, several Distribution Transformers were also damaged across TPDDL network, Guard Wires which hold the poles in place were also broken at various locations.

Assistance was provided to TPDDL consumers through the PGCIL Emergency Restoration System (ERS) for early restoration of affected lines, especially the DTL's 400/220 KV Mandola-Gopalpur. Due to this storm main supply from Bawana-Rohini Grid approx. 500 MW went out of system. However, TPDDL immediately arranged power from alternate source from Bawana-Shalimar Bagh-Rohini Grid. Also 220 KV line from Gopalpur to south of Wazirabad was activated thus restoring Wazirabad Water Supply in areas such as Ashok Vihar, Shalimar Bagh, Civil Lines etc.

TPDDL managed the crisis by having effective Disaster Management System, Contingency Planning, Inter- Grid Connectivity & Backfeeding and running the network on emergency mode which restored the power supply in TPDDL's area in record time of 36 hours. TPDDL strategically restored supply to critical areas like Delhi Jal Board Plants, DMRC, Railways, Hospitals, LG House etc. Supply to Rohini, Shalimar Bagh and Pitampura areas is
being alternatively fed through Bawana - Shalimar Bagh -Rohini line.

Reinforcing its commitment towards the citizens of Delhi in the hour of need, TPDDL staff managed to restore power in its area of operation (North and North-West Delhi) by restoring 50% of the power in less than 5 hours and 100 % restoration of sub- transmission lines and 80 % of distribution network within 12 hours of the disaster.