The primary role of the substation battery system is to provide a source of energy that is independent of the primary ac supply, so that in the event of the loss of the primary supply the substation control systems that require energy to operate can still do so safely.
The battery is required to supply the DC electrical requirements of the substation, including SCADA, control, protection indication, communications and circuit breaker switching operations when there is no output from the battery charger. This may be due to a loss of AC supply to the substation or a fault in the battery charger.
Batteries are to be accommodated in a cabinet within the substation control room - separate battery rooms are not required. Cells are to be mounted in accordance with the manufacturer's recommendations regarding separation between cells to allow air-flow for cooling and for easier access for removal if necessary.
The absolute minimum requirement is that the battery has sufficient energy to allow the substation to be made safe on loss of ac supply. A secondary requirement is to provide high capacity support to the battery charger for operating high current transient loads that are beyond the charger's capability.
110V DC supply cabling shall be sized to prevent voltage drop problems, particularly for long cable runs. Batteries are to be accommodated in a cabinet within the substation control room - separate battery rooms are not required.
AS 2676 - Installation and maintenance of batteries in buildings. AS 3011 - Electrical installations - Secondary batteries installed in buildings. AS 4044 - Battery chargers for stationary batteries. ENA Doc 001-2008 National Electricity Network Safety Code.