In power transmission systems, what factors contribute to the significance of DC voltage batteries?

The stations be equipped with two different types of batteries:

TYPE-1: The first type has a voltage of (48 V), and it is utilized with communication devices that connect the stations & the control centers. The purpose of utilizing the battery is to ensure that communication continue to take place between the stations and the control centers in the event that the station experiences a voltage loss as a consequence of any malfunction, whether it be internal or external.

TYPE-2: The second type of batteries may have a voltage (110 V or 220 V), depending on the design of the station. The purpose of using the battery is to maintain & to control all of the operations of the station in terms of separation and connection. Additionally, the function of using the battery is to maintain the operation of protective devices without interruption in case the voltage from the station breaks down. This facilitates in determining and assessing the cause of the malfunction when it occurs.

Moreover, there is a lighting system for emergencies that operates on continuous voltage in the absence of alternating voltage.