# Circuit Breakers / Power Quality (Needs Work)

33 Questions | Total Attempts: 575

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Along the power lines and connections, we have the circuits though which electric power moves from one place to another. The quiz below is all about circuit breakers and how they work. All the best.

• 1.
What type of circuit breaker can carry the most current on a HV trans line 555 kv and higher?
• A.

SF6

• B.

Oil filled

• C.

Gas filled (Gas other than SF6? Or “Vacuum”?)

• D.

Air

• 2.
What is the medium used for circuit interruption used on a 555 kV circuit breaker?
• A.

Air-blast

• B.

SF6

• C.

Oil

• D.

Nitrogen

• 3.
In the High-end side of an Automatic Transfer Switch (ATS), what is not true in an Industrial Station?
• A.

ATS will transfer to an alternate circuit when there's a fault

• B.

ATS will protect the customer from transient power

• C.

ATS does not rely on battery

• D.

ATS will not transfer to an alternate circuit when there's a fault

• 4.
A medium that is NOT used in power circuit breakers
• A.

Air break

• B.

SF6

• C.

Oil

• D.

CO2 gas

• 5.
Which is a characteristic of a circuit breaker?
• A.

Interrupting time = arcing time + opening time

• B.

Interrupting time = arcing time – opening time

• C.

Interrupting time = opening time – arcing time

• D.

None of the above

• 6.
At a temperature of 500 degrees Celsius in an oil filled equipment, the gas form is ----- in the absence of an arc
• A.

Methane

• B.

Hydrogen

• C.

Ethylene

• D.

Acetylene

• 7.
See the following system schematic For a Fault at F and a circuit breaker / relay no operation at 4, what would be the operation of the circuit breaker for a backup relay?
• A.

7,9,8,6,5

• B.

1,2,3,10,6

• C.

5,8,9,10,6

• 8.
Symmetrical components have the most usage in
• A.

Single phase systems

• B.

3 phase balanced systems

• C.

3 phase unbalanced systems

• 9.
In adjacent overlapping zones in the DWP 500-kv system, what component or device is normally overlapped?
• A.

Relay

• B.

Disconnect

• C.

Circuit breaker

• D.

Transformer

• 10.
Adjacent protective zone for voltage below 500KV, the overlap usually occurs at
• A.

Circuit Breaker

• B.

Disconnect

• C.

Relay

• D.

Transformer

• 11.
For transient stability, the most important factor is fast relaying
• A.

True

• B.

False

• 12.
Whats is the power factor of the circuit? What is the reactive power? What  sized capacitor can be used to correct for this reactive power?
• 13.
Which  is the symbol for a ACB with a thermal tripping protection?
• A.
• B.
• C.
• D.
• E.
• 14.
Which symbol represents an ACB with a magnetic overload protection?
• A.
• B.
• C.
• D.
• 15.
Which  is the symbol for a CB with a thermal/magnetic tripping protection?
• A.
• B.
• C.
• D.
• E.
• 16.
Which is the most severe fault on the department machine theory with respect to systematical components to solve the problem?
• A.

Single line to ground

• B.

Double line to ground

• C.

Three lines to ground

• D.

Line to line fault

• 17.
The momentary duty and the interrupting duty of a circuit breaker refers to:
• A.

No difference

• B.

The nominal and average short circuit current

• C.

The maximum short circuit current and the continuous short circuit current rating

• D.

The magnitude 0.5 to 1 cycle after a short circuit occurs and the magnitude of the current after 5 to 6 cycles

• 18.
The advantage of a breaker-and-a-half system versus a double breaker system is:
• A.

Lower Cost

• B.

Less complex relay protection

• C.

Greater reliability

• D.

Greater flexibility

• 19.
Is the highest load current that the circuit breaker is designed to carry for extended time periods:
• A.

Maximum Continuous Current

• B.

Maximum Interrupting Current

• C.

Interrupting Time

• D.

Closing Time

• 20.
Circuit breakers are rated according to this:
• A.

Maximum Continuous Current

• B.

Maximum Interrupting Current

• C.

Interrupting Time

• D.

Closing Time

• 21.
Is the period from the instant current begins to flow through the trip coil until the circuit breaker interrupts the fault:
• A.

Maximum Continuous Current

• B.

Maximum Interrupting Current

• C.

Interrupting Time

• D.

Closing Time

• 22.
Is the time it takes to close a breaker from the instant the close coil is energized until current begins to flow through the breaker
• A.

Maximum Continuous Current

• B.

Maximum Interrupting Current

• C.

Interrupting Time

• D.

Closing Time

• 23.
Which one do you like?
• A.

Option 1

• B.

Option 2

• C.

Option 3

• D.

Option 4

• 24.
The stability of an arc in a vacuum depends upon:
• A.

The contact material only

• B.

The contact material and its vapor pressure

• C.

The circuit parametersonly

• D.

A combination of both b & c

• 25.
Where voltages are high and current to be interrupted is low the preferred breaker is:
• A.

Air Blast CB

• B.

Oil CB

• C.

Vacuum CB

• D.

Any of the above

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