Power Generation & Distribution Flashcards
7 cards from real ETO practice questions. Tap to flip, then mark Knew It or Still Learning — missed cards come back until you master them.
Read the first 7 Power Generation & Distribution flashcards as text
Before connecting a second generator in parallel to the live main bus, which set of conditions must ALL be satisfied simultaneously?
Answer: Matching voltage, frequency, phase sequence, and phase angle
All four conditions—voltage, frequency, phase sequence, and phase angle—must match before closing the breaker to prevent destructive circulating currents and potential system collapse.
Which instrument provides visual indication of phase angle difference between an incoming generator and the live busbar during the synchronizing process?
Answer: Synchroscope
A synchroscope displays the relative phase angle and rate of change between the incoming machine and the bus, indicating the correct moment to close the circuit breaker.
What type of fault is most commonly encountered in ship electrical systems?
Answer: Earth (ground) fault
Earth faults are most common on ships because moisture, vibration, and physical wear deteriorate cable insulation, allowing current to flow from conductors to the ship's hull.
Which system automatically disconnects non-essential loads when a ship's power plant becomes overloaded?
Answer: Preferential tripping system
The preferential tripping system monitors total load and automatically sheds non-essential services in a predetermined priority order to protect generators from sustained overload.
What does reactive power (measured in VAR) represent in a ship's electrical distribution system?
Answer: Power exchanged to maintain magnetic and electric fields that performs no net useful work
Reactive power (VAR) is exchanged between generators and inductive or capacitive loads to sustain electromagnetic fields; it does not perform useful work but affects voltage stability and generator loading.
What does a low power factor in a ship's electrical system indicate about system operation?
Answer: A high proportion of reactive power relative to active useful power, increasing conductor losses
A low power factor means the system draws significant reactive current alongside active current, increasing I²R losses in conductors and reducing effective generator kW capacity.
Under STCW regulations, which table specifically defines the minimum standard of competence for Electro-Technical Officers?
Answer: Table A-III/6
STCW Table A-III/6 specifies the minimum standard of competence for electro-technical officers, covering electrical, electronic, and control engineering at the operational level.