Battery Flashcards
Batteries connected in series increase what?
Voltage
Batteries connected in parallel increase what?
Current
Batteries store and supply DC for use in what substation applications.
Relaying, S/C, breaker trip and close coils
In APS medium and large substations, the typical DC tripping voltage is based on……
125 VDC system
In APS medium and large substations, the typical DC S/C voltage is based on…..
24 VDC system
Battery voltage monitors and alarm for what conditions?
low tripping battery voltage, positive/negative grounds, high tripping battery voltage
Where would you expect to find the battery voltage monitor in the substation?
on a panel near the station annunciator
Where would you expect to find the battery charger and DC control panel in a substation?
In a separate room referred to as the battery room
Explain how a battery charger works?
It takes the incoming AC source and converts it to DC to charge the batteries. The charge rate can set to slow trickle (normal charge) or quick charge.
Explain the term “float”?
slow trickle charge rate used to maintain battery voltage level
Explain the term “equalize”?
Fast or quick charge rate to increase or boost voltage level.
Explain the term “charging amps”?
the electrical DC current supplied by the charger to charge the battery
Smaller substations on the APS system use a tripping battery voltage of….
125 VDC or 48 VDC
Why is it important to keep substation batteries well maintained?
Batteries provide DC stored energy critical to substation relaying and control. DC power is used to maintain substation reliability by supplying uninterrupted power to relays for clearing faults and to breaker trip/close coils for breaker open/close operations
Who would you notify for battery problems/maintenance?
Substation maintenance Dept battery crew
Who would you notify for other substation DC problems not directly related to batteries?
Substation maintenance Dept P&C group
Batteries require a controlled environment to operate efficiently and safely. What are some environmental considerations?
too cold, too hot, too little ventilation, too dirty, too close to sparks or fire, indirect sunlight and flammable storage
Where do battery chargers get their AC supply voltage?
from the substation station power transformer
What would happen if the AC supply to substation batteries was lost for an extended period of time
There would be no AC supply to the battery charge so the batteries could not re-charge. the batteries voltage would decay over time under DC load until the DC voltage would be too low to reliably operate the equipment.
What is the EMS display called that monitors battery voltage and from what directory can it be found?
Station battery voltage display, found from the Transmission Directory
How might a “control cubicle high temp” alarm affect station batteries?
Batteries are rated at 77 F. Higher temps can cause loss of some battery capacity and battery life.
Explain what a DS6Z1 125V DC alarm is?
DS=Desert Springs… 6Z1 = the alarm window ID at the substation annunciator. 125V DC = the battery monitor is in alarm
Substations are equip. with positive and negative ground lights. at what brilliancy, compared to each other, are they normally lit?
compared to each other that would normally be at equal intensity and dimly lit
How would you interpret a dim positive ground light with a brilliant negative ground light?
the substation has a strong ground on the negative leg
How would a strong ground impact tripping batteries.
the batteries would deplete more rapidly due to the increase constant load on the ground.
A Rose Garden station battery ground alarms comes in along with a low operating limit alarm at 118 V DC and a RSG442 SEL 351 relay trouble alarm. What do you think night have happened?
most likely would be RSG442 trip/close coil is burning, creating a strong DC ground, pulling the battery voltage down due to the ground current and putting the SEL 351 relay in alarm, since the SEL 351 monitors the trip coil voltage. DOC would need to be advised and prepared to unload the feeder
What would you expect if a battery voltage came in at 147V DC?
Have Sub Tech check battery voltage at the battery charger to insure EMS alarm is correct. Charger could have possibly be left on equalize (quick charge) return to “float”
A storm has swept through AZ and you receive a battery voltage at 122V DC with a station battery alarm, what would you expect to find?
Possibly door was opened by storm and the battery charger got wet and tripped off line or it internally grounded
A heavy storm swept through the Phoenix area and EMS is reporting rapidly decaying battery voltage at several unrelated substations, yet no battery monitoring alarms or GSA have came in. What might be the problem?
Wet transducers reporting incorrect EMS values
Who would you notify if you suspect wet transducers
EOS, the next working day
