'Hyderabad protected from grid collapse'

Half the country was plunged into darkness for over two days due to successive grid collapses recently. However, what affected the national capital apparently has least scope of affecting our State capital. Hyderabad is protected from a grid failure, owing to its proximity to Thermal Power Station at Ramagundam.

“Even in the event of grid collapse, our city will remain intact, thanks to the protective mechanisms installed at Ramagundam. The generating station can isolate itself from the rest of the grid when facing a collapse, and the power can be routed to the city,” says K.Raghu, an engineer with APTransco.

Normal life came to a complete halt in Northern India following recent simultaneous grid collapses.

Expressed through the simple word ‘outage’ it was no less calamitous than a gigantic time-machine coming to a screeching halt.

Southern grid, which includes transmission to Andhra Pradesh, Tamil Nadu, Kerala, Karnataka, and Pondicherry, escaped the brunt, thanks to its isolated existence from the NEW Grid (including North, East, North East and Western Grids).

For majority of the consumers, the phrase ‘grid collapse’ will probably create the visual of towers collapsing and conductors snapping in unison. However, put in simple words, it is nothing but all generating stations coming to a halt due to a fault in transmission. Technically, ‘Grid’ means interconnected transmission network which facilitates import and export of power among various regions, says Bhaskar, an engineer from CPDCL.

Grid facilitates the continuous transmission of electricity as it is produced, because consumption of power has to be simultaneous with generation. Grid Frequency is a critical parameter to ensure balance between demand and supply, the ideal measure of which is fixed at 50 hertz in India. The frequency is allowed to fluctuate a little on either side, but beyond that, it could result in grid disturbances and eventual collapse.

India is divided into five electrical regions, namely Northern, Southern, Eastern, Western and North Eastern, each with a Regional Load Dispatch Centre to ensure the Grid Frequency. Over the years, all regions except Southern region have achieved interconnectivity through grid synchronisation, which resulted in formation of NEW Grid and a National Load Dispatch Centre at Delhi. Southern Region, however, remained largely aloof, with its own grid network, but with the deferred prospect of being connected to the NEW grid.

Over drawal

In an interconnected grid, over drawal beyond a limit, unless warded off by the equipment called Relays, will result in collapse of generating stations. Relays will protect the system by tripping the supply at select locations when frequency drops beyond normal.

“Northern region heavily depended on Western and Eastern Grids for import of power. Transmission line between Western and Northern regions failed, reportedly due to over drawals by certain States, resulting in sudden decrease in supplies. Demand remaining the same, it increased the loads on the remaining generating stations which began to break down one after the other,” explained Mr. Raghu.

Southern region is less likely to face such a collapse, as all the power utilities here maintain strict grid discipline.