Control batteries: power system life savers

If protective devices and relays represent the ≫OPEN "nerves” of a medium- or high-voltage electric power system, the DC control battery distribution system represents the system\´s “bloodstream.” The battery distribution system delivers energy the battery provides to the control circuits of AC circuit breakers and other electrically operated interrupting equipment (the “muscle” of the electric power system), allowing operation. The battery is the DC power distribution system\´s “heart.” Reliable control battery systems assure proper functioning of well designed, installed, and maintained power systems. Battery system failure jeopardizes a power system by eliminating the DC control power source for AC system circuit breakers and protective devices. Failure to protect DC system components also could result in disastrous consequences for the battery system itself. The author discusses battery faults, battery protection, and battery maintenance. Battery charger faults and protection are also briefly mentioned, as are load protection, and DC system protection