The Central Electricity Regulatory Commission (CERC) has pulled up Powergrid Corporation of India Ltd (PGCIL), the country’s largest power transmission utility, for the large-scale tripping of power transmission lines that took place earlier this month due to dense foggy conditions in northern India.
In an order passed recently, the commission has directed PowerGrid to carry out a detailed study of the grid collapse that occurred on January 2 and submit a report explaining the reasons for grid disturbance, preventive steps taken so far and the remedial measures suggested.
The order, which followed a suo motu petition (acting on its own cognizance), states, “Grid disturbance on such a massive scale bringing the states in the northern region under partial blackout is a serious problem which goes to the root of planning and maintenance of the transmission system. The commission is deeply concerned about the grid disturbance and its impact on the people and economy in the region.”
Over two dozen transmission lines in the northern grid including Haryana, Punjab, Himachal Pradesh, Uttar Pradesh and Chandigarh tripped on two different occasions on January 2 due to heavy fog, disrupting supply in the entire region, including Delhi. The regional grid tripped in the early morning hours as well as late in the night, according to a preliminary report posted by the Northern Region Load Dispatch Centre (NRLDC) — a body under PowerGrid which maintains the operation of the transmission system in North — on its website. The grid failures had resulted in increased load causing technical glitches in the lines.
The reasons stated by NRLDC for grid collapse in its preliminary report include “depletion of transmission network due to heavy fog conditions and inadequate safety net in the form of automatic load shedding.”
The grid failure had affected 16,500 Mw of power load in the northern region and led to a generation loss of over 9,200 Mw from 17 power generating stations including Bhakra in Punjab; Dehar, Chamera-I and Jhakri in Himachal Pradesh; Baglihar in Jammu and Kashmir; and some power stations in Haryana. The northern region faces a monthly power deficit of around 4,000 Mw as against a demand of over 33,000 Mw.
Powergrid, however, maintains that it has all systems in place to deal with tripping due to fog. “We are well equipped to take care of any grid failure owing to foggy conditions. We have installed polymer insulators in most of the transmission systems, particularly in the National Capital Region. Punjab has not installed these insulators which lead to tripping of all the lines lying ahead of it. Also, the fog was unprecedented this time,” said a senior official from PowerGrid.
Tripping of power transmission lines occurs when heavy fog mixes with pollutants in the air and settles on the conventional porcelain disc insulators along the lines. PowerGrid deploys anti-fog polymer insulators along its transmission network in order to avoid such crisis. The problem, however, is deeper as the company has to import these polymer insulators from China and Korea in the absence of domestic manufacturing capacity. “We have placed orders for more insulators,” the official said.
