LADWP ELECTRIC STATION
OPERATOR (CIRCUIT BREAKERS,
LATEST
DISCONNECTS, TRANSFORMERS)
QUESTIONS AND ANSWERS 2026 - 2027
A transformer whose secondary or output voltage is lower that its input
or primary voltage is called a step-________ transformer. - ANSWERS-
down
Larger transformers are about _____% efficient. - ANSWERS-98
The amount of __________ delivered by the secondary winding is less
than the amount supplied to the primary winding. - ANSWERS-power
__________ is stepped down, whenever voltage is stepped up, and vice
versa. - ANSWERS-current
Large three phase power transformers are generally referred to as
transformer __________ or simply, __________. (same word) -
ANSWERS-banks
__________ allow generators to be connected to the DWP Transmission
System. These banks typically step up the voltage from 18kV, the
nominal voltage of the generator, to transmission voltages of either
138kV or 230kV. - ANSWERS-banks
END OF
PAGE
1
, LADWP ELECTRIC STATION
OPERATOR (CIRCUIT BREAKERS,
LATEST
DISCONNECTS, TRANSFORMERS)
QUESTIONS AND ANSWERS 2026 - 2027
_________ banks connect together buses of different voltages such as
138kV to 230kV. - ANSWERS-bus
__________ banks are dedicated to individual lines. - ANSWERS-line
_________ banks step down 138kV or 230kV Transmission System
voltage to 34.5kV - the Department's Subtransmission System Voltage. -
ANSWERS-power
__________ in distribution stations step down 34.5kV to 4.8kV - the
Department's Distribution System voltage. - ANSWERS-banks
____________ transformers provide power to small factories,
businesses, or residential areas. - ANSWERS-Distribution
The __________ voltage of distribution transformers is typically 4.8kV.
- ANSWERS-primary
END OF
PAGE
2
, LADWP ELECTRIC STATION
OPERATOR (CIRCUIT BREAKERS,
LATEST
DISCONNECTS, TRANSFORMERS)
QUESTIONS AND ANSWERS 2026 - 2027
The ___________ voltage of distribution transformers is typically 480,
240, or 120 volts, single or three-phase power, depending on the
installation and customer needs. - ANSWERS-secondary
Station ___________ transformers are the distribution transformers for
substations. They provide the station with single-phase power for light,
etc. and three-phase power for such things as fans, pumps, gate motor,
compressors, etc. - ANSWERS-service
A special type of transformer is the __________ transformer. They are
used for measurement of electrical quantities and for control purposes. -
ANSWERS-instrument
Transformer ratios of 400:1 are typically used in __________
transformers, depending on the installation and equipment needs. -
ANSWERS-instrument
__________ transformers are used to step voltage down to a safe value,
typically 120 volts. - ANSWERS-potential
END OF
PAGE
3
OPERATOR (CIRCUIT BREAKERS,
LATEST
DISCONNECTS, TRANSFORMERS)
QUESTIONS AND ANSWERS 2026 - 2027
A transformer whose secondary or output voltage is lower that its input
or primary voltage is called a step-________ transformer. - ANSWERS-
down
Larger transformers are about _____% efficient. - ANSWERS-98
The amount of __________ delivered by the secondary winding is less
than the amount supplied to the primary winding. - ANSWERS-power
__________ is stepped down, whenever voltage is stepped up, and vice
versa. - ANSWERS-current
Large three phase power transformers are generally referred to as
transformer __________ or simply, __________. (same word) -
ANSWERS-banks
__________ allow generators to be connected to the DWP Transmission
System. These banks typically step up the voltage from 18kV, the
nominal voltage of the generator, to transmission voltages of either
138kV or 230kV. - ANSWERS-banks
END OF
PAGE
1
, LADWP ELECTRIC STATION
OPERATOR (CIRCUIT BREAKERS,
LATEST
DISCONNECTS, TRANSFORMERS)
QUESTIONS AND ANSWERS 2026 - 2027
_________ banks connect together buses of different voltages such as
138kV to 230kV. - ANSWERS-bus
__________ banks are dedicated to individual lines. - ANSWERS-line
_________ banks step down 138kV or 230kV Transmission System
voltage to 34.5kV - the Department's Subtransmission System Voltage. -
ANSWERS-power
__________ in distribution stations step down 34.5kV to 4.8kV - the
Department's Distribution System voltage. - ANSWERS-banks
____________ transformers provide power to small factories,
businesses, or residential areas. - ANSWERS-Distribution
The __________ voltage of distribution transformers is typically 4.8kV.
- ANSWERS-primary
END OF
PAGE
2
, LADWP ELECTRIC STATION
OPERATOR (CIRCUIT BREAKERS,
LATEST
DISCONNECTS, TRANSFORMERS)
QUESTIONS AND ANSWERS 2026 - 2027
The ___________ voltage of distribution transformers is typically 480,
240, or 120 volts, single or three-phase power, depending on the
installation and customer needs. - ANSWERS-secondary
Station ___________ transformers are the distribution transformers for
substations. They provide the station with single-phase power for light,
etc. and three-phase power for such things as fans, pumps, gate motor,
compressors, etc. - ANSWERS-service
A special type of transformer is the __________ transformer. They are
used for measurement of electrical quantities and for control purposes. -
ANSWERS-instrument
Transformer ratios of 400:1 are typically used in __________
transformers, depending on the installation and equipment needs. -
ANSWERS-instrument
__________ transformers are used to step voltage down to a safe value,
typically 120 volts. - ANSWERS-potential
END OF
PAGE
3
