Deluge may not hit power supply in Mumbai this year

If Mumbai is deluged this year, power cuts might still hit the city. However, power supply could be restored much faster once the water recedes, unlike in July 2006 when Mumbai, after a record 994 mm of rainfall submerged the city, and power was not restored for a long time.

Reliance Energy Ltd (REL,) that supplies power to the suburbs of Mumbai and New Mumbai, has spent Rs 30 crore (Rs 300 million) to ensure better power supply restoration system this year.

"We have raised to a higher level 195 of the 197 distribution sub-stations that were submerged last year. This means that although we will be compelled to discontinue power supply to waterlogged areas where livewires are submerged, the equipment would still be in good condition to switch back into action as soon as the water recedes," said Lalita Jalan, chairman of REL's distribution business in Mumbai and Delhi.

Jalan explained that since meters in residential complexes cannot be relocated to higher ground, power supply would have to be discontinued where meter boxes get submerged, to prevent electrocution.

Apart from taking care that equipment are least affected by water-logging, REL would have the advantage of its Supervisory Control And Data Acquisition (SCADA) system. This system helps detect faults and switches off power supply in the affected areas instantly. The easy and swift detection of faults would also ensure faster repairs of these faults.

However, Jalan explained that repairing the underground faults is not possible unless an area is dry. This could, therefore, delay restoration of power to some low-lying areas where it is not easy to pump out the water.

REL's automated ring main unit (RMU) is also expected to bring some respite to certain areas. This system inter-connects a chain of supply points to alternative distribution transformers, unlike the radial model earlier where various supply points were connected to a single transformer.

This means that if one transformer fails, the entire network is not affected anymore. Moreover, only the areas with faults in a particular network would be cut off from the suply chain, sparing the rest of the network suffering blackouts.

The distribution company has also stocked spare parts, tools and equipment in 10 strategic locations spread across its supply area.

Among other emergency arrangements, REL has also stocked seven mobile diesel generating sets with capacities ranging between 150 kilo volt ampere (KVA) and 500 MVS. These will provide temporary respite to residents during hours of black out.

All arrangements have been made to face a catastrophe and not just for the regular rainfall. The city can easily withstand a 250 mm rain, Jalan said. However, as a long-term remedy, the chairman stressed the importance of an underground utility ducts and a developed drainage system.

REL has also prepared itself for a peak shortage of 450 Mw expected in October, once the monsoons recede.

The company has tied up for 150 Mw to 200 Mw of fixed power at rates higher than Rs 6.60 per unit, Jalan informed.