CERC asks Power Grid to probe last month's disturbances

Electricity regulator CERC has directed Power Grid to probe incidences of collapse of transmission towers in the Northern region last month that happened in the wake of inclement weather.

While asking transmission major Power Grid to submit the report on "load crash" in two weeks time, CERC said collapse of transmission towers and lines tripping of such a large magnitude is alarming and needs to be investigated in detail.

On May 30, the Northern Region grid had experienced sharp drop in demand due to rain, dust storm/thunder storm, mainly in Uttar Pradesh, Haryana, Uttarakhand and Delhi.

The region's electricity demand started declining at a rate of about "200 MW/min and reached to 32,780 MW at 1715 hrs, around 8,000 MW less than demand at corresponding time of preceding day, and the power resulted in high frequency and high voltage in the system," CERC said.

In its order yesterday, the Central Electricity Regulatory Commission (CERC) directed Power Grid to "investigate into the incidences of collapse of transmission towers and tripping of transmission lines on May 30, 2014".

Power Grid has been asked to look into the wind speed which caused damage to towers and wind level for which the towers have been designed, year of commissioning of towers and updation on the maintenance activity, among others.

"It has been noticed that during this period (May 30), 68 AC transmission lines along with one HVDC Bi-pole line tripped which led to load crash of about 8,000 MW in Northern Region including 3,500 MW in Delhi.

"As per weather forecast of Indian Meteorological Department and NOWCAST, all constituents of NR (Northern Region) were alerted about the likelihood of the storm," the order said.

Citing the load crash report, CERC said the storm caused damage to many towers including two towers of 765 kV and one of 400 kV lines and 10 towers on various 220 kV transmission lines in Delhi.

Besides Power Grid, Power System Operation Corporation Ltd (NLDC) is also a respondent in the petition.

The watchdog has also asked POSOCO (NLDC) to file on affidavit, by month end, impact of collapse of transmission towers and lines tripping on the system operation and grid security, among others.

National Load Despatch Centre (NLDC) has the mandate to ensure optimum scheduling and despatch of electricity among the Regional Load Despatch Centres.