The alternate source for emergency systems are required to be equipped with ground-fault protection of equipment.
False
Which ANSI/IEEE standard
... [Show More] covers SF6 circuit breakers?
C37.04
00:53
01:32
You measure the winding resistance of a 12.4kV, 1000kVA, Delta-Delta connected transformer with a 100A test set. H1-H2 measures 42.0 microhms, H2-H3 measures 41.9 microhms, and H3-H1 measures 84.0 microhms. What can you conclude from these readings?
One phase of the transformer is open.
When monitoring for entries involving a decent into atmospheres that may be stratisfied, the envelope should be tested at a distance of approximately _____ feet in the direction of travel and to each side.
4
The transformer manufacturer should be consulted if winding-resistance test values vary by more than _____ percent from factory test values or between adjacent phases according to NETA acceptance testing standards.
2
A DC shunt motor should never be operated:
with the field circuit open
What is the expected torque (pound-feet) value of a 3/8" Grade 5 bolt?
20
The generally accepted limits of deviation from the nominal 60Hz utility power frequency is:
.50Hz
Power Factor testing is least effective on which of the following?
MV Cable
Which of the following insulating liquid tests is optional when maintenance testing a 13.2kV-4.16kV 1500kVA transformer with silicone fluid per NETA standards?
ASTM D1298
Panelboards equipped with snap switches of rating 30 amps or less shall be provided with over-current protection of not more than _____ .
200 amps
Underground service conductors between the terminals of service equipment and service lateral or underground service conductors are termed as _____ .
Service Entrance Conductors
00:37
01:32
What is a dual element fuse used for?
Operate with a temporary overload
The full-load current for a single-phase alternating current 115 volt, 1 horsepower motor is which of the following:
16 A
Infrared surveys should be performed during periods of maximum possible loading but not less than _____ % of rated load of the electrical equipment being inspected.
40
Decreasing the opening time of the overcurrent protective device will decrease Arc-Flash hazards.
true
In a wye connected system, without neutral grounding, zero sequence currents are:
zero
When evaluating insulation test results on a medium-voltage, air-magnetic circuit breaker, what quantity is evaluated?
watts-loss
In accordance with NETA and IEEE standards, the correct acceptance test voltage (dc) for 35KV rated EPR 133% insulation level cable is?
124kV
Calculate the circuit time constant of an inductor having resistance value of 100 ohms and an inductance value of 4 Henry:
0.04 sec
T=L/R
Transformer polarity:
Is of concern when multiple sets of primary and secondary windings are interconnected
Identify the least reliable power system arrangement:
Radial w/ Primary Selectivity
The hot collar bushing test should be performed using which of the following test modes?
UST
GST
GST-g
R rated fuses are used for:
Protection for motors
R-rated fuses provide required short-circuit protection for medium voltage motors, motor controllers and associated circuitry. Relays provide both overload protection and locked rotor protection to the motor.
Which of the following would be a factor in choosing between 100%, 133%, and 173% Medium voltage cable for a power system?
Ground Fault protection
During the performance of a thermographic scan of similar components within the switchboard that are under similar load, at what temperature difference does NETA recommend investigation?
1-3 deg C
In calculating the thickness of insulators for high-voltage AC power lines, which type of measurement is the best to use for voltage?
Peak
What type of sensing element can measure a transformer's hottest-spot (winding) temperature directly?
Fiber optic cable
Before acceptance testing begins, what steps should be taken as part of the commissioning process?
Inspect devices for variations from design specifications
Which of the following would not significantly reduce ground resistance?
Increased ground rod diameter
In a typical stepped distance protection scheme, Zone 4 is used as a backup for an adjacent transmission line in the reverse direction in case the protection in that line fails. This zone is usually set to _____ of the adjacent line.
20-50%
The power factor of SF6 circuit breaker bushings is to be within _____ percent of nameplate per NETA-ATS.
10%
Two 5H inductors connected in series are subjected to an electric current that changes at a rate of 4.5 amps per second. How much voltage will be dropped across the series combination?
45.00
V = L(di/dt)
Be aware of "Two 5H inductors" - Inductors Add
Hard hats suitable for the performance of low voltage electrical work, but NOT for higher voltage electrical work, are identified as being:
Class G
Which of the following would NOT be part of the test plan for a 21 device?
Determine pickup frequency
Confined space attendants may be assigned to monitor more than one permit space.
True
Which of the following conditions produces ferroresonance?
XC = XL
Cell internal ohmic values (resistance, impedance or conductance) should not vary by more than _____ between identical cells that are in a fully charged state.
25 percent
An interfacial tension test value indicates the_______.
Attraction between water and oil
What is the maximum allowable water content for FR3 insulating liquid received in new equipment?
25 ppm
Which type of fiber optic cable is specifically designed for harsh outdoor environments?
loose-tube
According to ANSI/NETA MTS, how often should a medium voltage switchgear with a high reliability requirement in good condition be electrically tested and maintained?
18 months
How often do you need to update your NFPA 70E lock out/tag out training?
every 3 years
Which of the following statements is true according to the NEC definition of a switchboard?
Switchboards may be accessible from the front or from the rear.
In a typical stepped distance protection scheme, Zone 3 is set to overreach to an adjacent transmission line as a backup in case Zone 2 in that line fails. This zone is commonly set to _____, assuming the impedance of both lines are the same.
220%
A typical value for insulation power factor tests (CHL) of a large dry-type power transformer is ____ percent or less.
2.0
As an industry standard, IEEE recommends that LTC services be performed how often?
every three to five years
Which of these formulas would be most appropriate for a Field DC Acceptance test on rotating equipment insulation?
0.8 x Factory AC Test x 1.6
What action level would apply to a Delta T of 25°C between component and ambient air?
Monitor until corrected
In a zone-interlocked low voltage circuit breaker protection scheme, the trip unit responsible for clearing the fault is inoperative. Which statement is most true?
The next circuit breaker upstream will trip
What would a reactor placed at the end of a long transmission line be used for?
Current control
Which of the following is not a common diagnostic test that can be performed using the tan-delta test set:
VLF-DC
What is the NETA-MTS recommended maximum AC test voltage for a high-potential test on a three-phase, 15kV line sectionalizer with a rated impulse withstand voltage of 95kV?
26.2kV
A grounding connection to earth from a lightning protection system should be made at diagonal corners of the structure.
True
Which of the following would significantly reduce ground grid impedance?
Double ground rod length
What is the minimum acceptable megohm value for a metal-oxide surge arrester rated 15kV with an MCOV rating of 12.7kV per NETA standards?
5,000 Megohms
What is the minimum acceptable test limit for an ASTM D1816 (2mm gap) test on mineral oil used in new 230kV equipment?
60kV
The ________ rating refers to the maximum current a protective device, such as a fuse or circuit breaker, can safely interrupt.
interrupting
Distance Relays may be directional or non-directional.
True
Which of the following would you not expect to find in an IEC 61850 object name?
Device Address [Show Less]