Back-up power for Substations and captive power plants Electrical substations are the interface system between power-generating stations, the distribution grid, and the transmission grid. The voltage levels are stepped up and stepped down as per grid requirements. The DC supply system in an electrical substation plays a very important role in providing DC power to critical components like numerical relays, tapping coils, alarms and hooters, and communication devices. The traditional way of powering DC with lead-acid batteries can be replaced with our tailor-made LFP Grid Solution with just a drop-in change.