Substation
Apprentice
Substation
Bonus round
100
Why do experienced substation workers statistically suffer more serious injuries than new apprentices?
The biggest factor.
Experienced workers:
Have done the task hundreds of times
Have done it safely 99% of the time
Start to associate the task with success, not danger
100
What document shows how all substation equipment is electrically connected?
The one-line diagram.
100
On a metal clad breaker in what circumstance must you wear the following PPE
• Safety Glasses with side protection or approved goggles
• FR rated face shield
• Approved hard hat
• 20KV rubber gloves with leather protectors
• Approved safety shoes or boots
• Approved fire retardant clothing (Review SOPR PPE requirements)
• FR Coveralls
100
If a F switch bottle can't be detached, what do you do?
200
With a breaker and half scheme what would happen if the mid breaker fails to open during a fault ?
Shared breaker, shared outage
Both the bus breakers will open
200
What equipment is designed to interrupt heavy fault current?
A circuit breaker
200
What happens if batteries fail but the battery charger is still operations ?
If the station batteries fail but the battery charger is still operating, the DC system may stay energized, but it becomes unstable and unreliable. You lose your backup capability.
300
Why would a NLTC step down transformer have its ability to tap on the highside instead of the lowside?
NLTC taps are on the high-voltage side because the current is lower, which makes the tap changer smaller, and more reliable.
300
What are A & B. contacts
breaker control circuits, “A” and “B” contacts are auxiliary contacts that change state based on the position of the breaker. They are critical for indication, interlocking, and protection logic.
A Contacts (52a)
Definition:
- Closed when the breaker is CLOSED
- Open when the breaker is OPEN
B Contacts (52b)
Definition:
Closed when the breaker is OPEN
Open when the breaker is CLOSED
300
Before each use, what must you do with Protective Grounds (TPG) ?
300
With great power comes great responsibility
400
On a gas detector gauge what limit will alarm will be shown ?
200cc
400
Fault pressure relay & the test port cap is secured
400
What must you do with TPG's before installing.
500
Why does solar site GSU have a 3rd winding ?
Tertiary (Delta) Winding – The “Extra” One
This is the winding most people ask about 👇
What the tertiary winding does:
🔹 Handles Triplen Harmonics
3rd harmonics circulate in the delta
Prevents distortion on generator and transmission windings
🔹 Improves Stability During Unbalanced Faults
Provides a path for zero-sequence and unbalanced currents
Keeps voltages from floating during SLG faults
🔹 Supports Auxiliary Equipment (Sometimes)
Can feed:
Station service transformers
Reactors
Resistors
Even if unused, it still serves a stabilizing role
500
When transformer experiences a ground instantaneous fault what is the process of events that occur. what is most important regarding the lowside GB ?
The F switch will open, then the GB. The GB must fully clear the receiver / interrupter arm before the bus tie closes.
500
Phase-to-Phase vs Phase-to-Ground Faults
Which fault produces higher fault current
Which one typically causes more equipment damage?
Which fault produces HIGHER fault current?
Phase-to-Ground fault
WHY
In a solidly grounded system, the system neutral is intentionally connected to ground with very low impedance.
Which fault causes MORE equipment damage?
Phase-to-Phase fault
WHY
Even though phase-to-phase faults often have slightly lower current, they are far more mechanically and thermally destructive