Section 33 in The Central Electricity Authority (Technical Standards for Connectivity to the Grid) Regulations, 2007
33. kV and below 66 kV: There shall be one HT supply.
(b)for direct current (DC) Supply (Applicable to new sub-stations): Sub-stations of transmission system for 132 kV and above and sub-stations of all generating stations: There shall be two sets of batteries, each equipped with its own charger.For sub-stations below 132 kV: there shall be one set of battery and charger.(7)Earth Fault Factor for an effectively earthed system shall be not mare than 1.4.
