A total of 22 power transmission lines went into “forced outage” in the northern grid on May 7, when a severe dust storm hit north India at various places. With officials working overtime, these lines were revived either on May 7 or May 8.
Building India: 22 power lines face ‘forced outages’ after dust storm hit north India
latest data of Northern Regional Load Dispatch Centre (NRLDC) show that out of these 22 lines, 10 are owned by India’s largest power transmission company Power Grid Corporation of India Limited (PGCIL). The PGCIL, in which the Central government owns 56.91 per cent share, “No forced outages of Power Grid lines on May 7, 2018. These lines tripped due to transient faults at the time of storm and same were restored within an hour of tripping.”
Remaining 12 lines belong to utilities owned by various state governments. Five transmission lines of Haryana Vidyut Prasaran Nigam Ltd and three lines of Uttar Pradesh Power Corporation Limited also witnessed forced outage on May 7. Two lines of Delhi Transco Limited and one line each of Uttarakhand Power Corporation Limited and Bhakra Beas Management Board (BBMB) also stopped working on May 7.
22 power lines face ‘forced outages’ after dust storm hit north India
A similar incident happened on May 30, 2014, when a record 30 transmission towers either collapsed or were severely damaged across northern India after a dust storm, highlighting the fragility of the grid infrastructure. The PGCIL said: “On May 30, 2014, three lines of Power Grid had suffered damages due to excessively high wind speeds. Due to climate change, wind speed has increased in Northern India and wind zone has increased to level 5 against design value of Wind Zone-4 of these lines. Strengthening of towers has been taken up…to avoid such failures. The work of strengthening is being carried out progressively in phased manner.”
As per the Bureau of India Standards’ Code of Practice for Design of Wind Loads for Buildings and Structures (IS-875 Part III), the basic design of structures like buildings in areas around the national capital region and most of the northern region should factor in wind speed of 47 metres per second, which works to around 169 kmph.
Additionally, for installations in open areas and high structures like transmission towers, a margin of 10-15 per cent is to be further built in. For structures like high-tension 765kV towers, an extra safety margin of 7 per cent should be factored in.
The India Meteorological Department (IMD) stated on Tuesday: “Under the influence of the present Western Disturbance over J&K and neighbourhood; the cyclonic circulation over Haryana and neighbourhood and a north-south trough from East UP to Vidarbha in lower levels, thunderstorm accompanied with gusty winds and moderate squall (50-70 kmph speed) is very likely to continue at isolated places over J&K, Himachal Pradesh, Uttarakhand, Punjab, Haryana, Chandigarh and Delhi and West UP during next 24 hours…”