HV Exit Exam • Set 7 Question 7 of 30

For extra-high-voltage (EHV) transmission networks above 220 kV, which circuit breaker type is predominantly selected?

✓

Direct Answer

Option C: SF6 gas circuit breaker

SF6 circuit breakers are standard for EHV systems due to their superior dielectric strength, fast arc quenching, and compact gas-insulated switchgear (GIS) design.

All Options

Bulk oil circuit breaker

Air-break circuit breaker

SF6 gas circuit breaker (Correct Answer)

Minimum oil circuit breaker

Detailed Explanation & Context

SF6 circuit breakers are standard for EHV systems due to their superior dielectric strength, fast arc quenching, and compact gas-insulated switchgear (GIS) design.

Relevant Framework: STCW 2010 Manila Amendments • DG Shipping E-Learning & Exit Exam Standards • High Voltage Safety Officer & Switchgear Operations (HV).

Practice Full HV Set 7

Test yourself with 30 interactive questions, live timer, and instant score.

Launch Practice Simulator →

Question Discussion & Notes

Have a doubt, memory trick, or exam update? Share your insights with fellow mariners.

Loading mariner discussions...

« Previous Question Next Question »

More Questions in HV Set 7

View All 30 →

Q1 High Rupturing Capacity (HRC) fuses provide the most effective and rapid protection under conditions of: Q2 For high-speed motor circuit breakers, the total closing time from command signal to contact touch is typically in the order of: Q3 Which type of protective relay is commonly used to protect electric motors against continuous moderate overload? Q4 According to Preece's Law, the fusing current (I) of a fuse wire is related to its wire diameter (D) by the relationship: Q5 In a circuit breaker contact gap, ionization of the medium is NOT facilitated by: Q6 An ideal fuse wire material should possess which combination of physical properties? Q7 For extra-high-voltage (EHV) transmission networks above 220 kV, which circuit breaker type is predominantly selected? Q8 The number of power-frequency AC cycles in which a modern high-speed circuit breaker completes its tripping and arc clearing operation is: Q9 Which of the following metals is best suited for manufacturing precision HRC fuse elements due to its resistance to oxidation and low specific resistance? Q10 In a circuit breaker, the current that is flowing through the contacts at the precise instant of contact separation is known as the: