LADWP Electric Station Operator
Exam – Los Angeles Department
of Water and Power –2026–2027
Edition
Exam Overview & Qualification Requirements
The Electric Station Operator (5224) position with the Los Angeles Department of
Water and Power involves operating high voltage electric and auxiliary equipment in
hydroelectric generating, receiving, and distributing stations. All entry-level
positions are temporary training positions requiring successful completion of an
intensive 24-month on-the-job training program.
Feature Details
Salary Range $72,119 - $137,286 annually
Training Period 24-month intensive OJT program
Work Schedule 24/7 operations, rotating shifts, holidays, weekends, on-call duty
Locations Los Angeles, Owens Valley, Castaic, Adelanto, Nevada
License Required Valid California Class C driver's license within 30 days of appointment
,SECTION 1: ELECTRICAL THEORY & FUNDAMENTALS
Question 1
An Electric Station Operator is monitoring a 34.5 kV bus and observes that the line-
to-line voltage has dropped to 31 kV. What is the approximate percentage voltage
drop from nominal?
A. 5.2%
B. 10.1%
C. 15.3%
D. 20.4%
Answer: B. 10.1%
Rationale: Percentage voltage drop = [(Nominal – Actual) / Nominal] × 100 = [(34.5
– 31) / 34.5] × 100 = (3..5) × 100 = 10.14% ≈ 10.1%. This exceeds typical
allowable voltage variations (±5%) and would require operator investigation and
possible corrective action. Option A miscalculates using 31 as the denominator.
Options C and D represent significantly larger deviations.
Question 2
In a three-phase AC system, the phase-to-phase voltage is 480 volts. What is the
approximate phase-to-neutral voltage?
A. 240 volts
B. 277 volts
C. 340 volts
D. 480 volts
,Answer: B. 277 volts
Rationale: In a wye-connected three-phase system, V_phase-to-neutral =
V_phase-to-phase / √3. Therefore, .732 = 277 volts. This relationship is
fundamental for operators when verifying metering and protection circuits. Option A
(240V) represents a single-phase 480/240 split-phase configuration. Option C
incorrectly uses a different multiplier. Option D confuses line and phase quantities.
Question 3
An operator measures zero-sequence current flowing through a transformer
neutral. This indicates:
A. Balanced three-phase loading
B. An unbalanced fault condition or ground fault
C. Normal capacitive charging current
D. Transformer core saturation
Answer: B. An unbalanced fault condition or ground fault
Rationale: Zero-sequence current (I₀) flows only during unbalanced conditions
involving ground. In a balanced three-phase system, the vector sum of phase
currents equals zero, and no neutral current flows. The presence of zero-sequence
current indicates a ground fault, unbalanced loading, or a line-to-ground condition.
Question 4
An Electric Station Operator is performing switching on a 230 kV circuit. Which
parameter is MOST critical to verify before opening a circuit breaker to de-energize
the line?
, A. Ambient temperature
B. Load current on the circuit
C. Humidity level
D. Time of day
Answer: B. Load current on the circuit
Rationale: Before opening a circuit breaker, the operator must verify that the load
current is within the breaker's interrupting rating and that the circuit can be safely
de-energized without overloading other equipment or causing customer outages.
Load current directly affects the arc energy and switching safety.
Question 5
In a substation, the potential transformer (PT) ratio is 2000:1. If the secondary
voltmeter reads 115 volts, what is the primary voltage?
A. 57.5 kV
B. 115 kV
C. 230 kV
D. 345 kV
Answer: C. 230 kV
Rationale: Primary voltage = Secondary voltage × PT ratio = 115 V × 2000 =
230,000 V = 230 kV. PTs step down high voltages to safe, measurable levels for
metering and protection relays. Accurate PT ratios are essential for correct
protection settings and metering.
Exam – Los Angeles Department
of Water and Power –2026–2027
Edition
Exam Overview & Qualification Requirements
The Electric Station Operator (5224) position with the Los Angeles Department of
Water and Power involves operating high voltage electric and auxiliary equipment in
hydroelectric generating, receiving, and distributing stations. All entry-level
positions are temporary training positions requiring successful completion of an
intensive 24-month on-the-job training program.
Feature Details
Salary Range $72,119 - $137,286 annually
Training Period 24-month intensive OJT program
Work Schedule 24/7 operations, rotating shifts, holidays, weekends, on-call duty
Locations Los Angeles, Owens Valley, Castaic, Adelanto, Nevada
License Required Valid California Class C driver's license within 30 days of appointment
,SECTION 1: ELECTRICAL THEORY & FUNDAMENTALS
Question 1
An Electric Station Operator is monitoring a 34.5 kV bus and observes that the line-
to-line voltage has dropped to 31 kV. What is the approximate percentage voltage
drop from nominal?
A. 5.2%
B. 10.1%
C. 15.3%
D. 20.4%
Answer: B. 10.1%
Rationale: Percentage voltage drop = [(Nominal – Actual) / Nominal] × 100 = [(34.5
– 31) / 34.5] × 100 = (3..5) × 100 = 10.14% ≈ 10.1%. This exceeds typical
allowable voltage variations (±5%) and would require operator investigation and
possible corrective action. Option A miscalculates using 31 as the denominator.
Options C and D represent significantly larger deviations.
Question 2
In a three-phase AC system, the phase-to-phase voltage is 480 volts. What is the
approximate phase-to-neutral voltage?
A. 240 volts
B. 277 volts
C. 340 volts
D. 480 volts
,Answer: B. 277 volts
Rationale: In a wye-connected three-phase system, V_phase-to-neutral =
V_phase-to-phase / √3. Therefore, .732 = 277 volts. This relationship is
fundamental for operators when verifying metering and protection circuits. Option A
(240V) represents a single-phase 480/240 split-phase configuration. Option C
incorrectly uses a different multiplier. Option D confuses line and phase quantities.
Question 3
An operator measures zero-sequence current flowing through a transformer
neutral. This indicates:
A. Balanced three-phase loading
B. An unbalanced fault condition or ground fault
C. Normal capacitive charging current
D. Transformer core saturation
Answer: B. An unbalanced fault condition or ground fault
Rationale: Zero-sequence current (I₀) flows only during unbalanced conditions
involving ground. In a balanced three-phase system, the vector sum of phase
currents equals zero, and no neutral current flows. The presence of zero-sequence
current indicates a ground fault, unbalanced loading, or a line-to-ground condition.
Question 4
An Electric Station Operator is performing switching on a 230 kV circuit. Which
parameter is MOST critical to verify before opening a circuit breaker to de-energize
the line?
, A. Ambient temperature
B. Load current on the circuit
C. Humidity level
D. Time of day
Answer: B. Load current on the circuit
Rationale: Before opening a circuit breaker, the operator must verify that the load
current is within the breaker's interrupting rating and that the circuit can be safely
de-energized without overloading other equipment or causing customer outages.
Load current directly affects the arc energy and switching safety.
Question 5
In a substation, the potential transformer (PT) ratio is 2000:1. If the secondary
voltmeter reads 115 volts, what is the primary voltage?
A. 57.5 kV
B. 115 kV
C. 230 kV
D. 345 kV
Answer: C. 230 kV
Rationale: Primary voltage = Secondary voltage × PT ratio = 115 V × 2000 =
230,000 V = 230 kV. PTs step down high voltages to safe, measurable levels for
metering and protection relays. Accurate PT ratios are essential for correct
protection settings and metering.
