Why is there is no “theoretical” potential between a phase and ground on a delta system?
D) All of the above
When changing out a transformer that is paralleled with another transformer, what
needs to be done before disconnecting the primary connection with a shotgun or switch
stick?
A) Secondary phase conductors must be disconnected from the transformer
When using a voltmeter to perform phasing on two known energized secondary
circuits, what does a “0.00” reading indicate?
C) The two circuits being tested are the same phase
What does the use of supervisory control equipment permit?
C) Allows remote control of a substation from a system control center
Which of the following is true of a transformer nameplate listing one secondary voltage
of 277 volts?
D) The transformer has only one secondary coil
Why is oil used in transformers?
C) Both To cool the core and coil assemblies & Transformer oil has high dielectric strength and adds to the insulation value of the transformer
How is an insulator hood properly installed?
D) It will overlap the line hose when properly installed
What is the function of a turbine in an electric generation plant?
D) It converts steam energy to mechanical energy that turns a generator
There are four basic types of switched capacitor banks. Which of the following are switched capacitor banks?
A) Voltage, current, VAR, and Temperature
Which piece of special equipment uses a bandwidth relay and a time delay relay to limit hunting or over operation of its components?
B) A step voltage regulator
What street light circuit requires the use of a pilot wire?
B) A series streetlight or multiple light circuits
What does the hipot adaptor for phasing sticks allow you to do?
D) It applies a DC voltage on the cable to test them before they are energized
Why are batteries used to provide power to operate switches, relays, and other equipment in substations?
C) So power will be available for operations to recover from an emergency
Which situation will cause a substation breaker to operate automatically?
D) All the above
On a primary meter installation, how is the current transformer wired?
A) It is wired in series with the load
What type transformer is used in a series street lighting circuit?
B) Constant current
What does an arrestor do?
C) It is a large spark gap that provides a low resistance path to ground for voltage surges caused by lightening or switching to protect equipment
What would cause an ATO to switch from the preferred feed to the alternate feed?
C) A power interruption on the preferred feed for a preset amount of time
A common single-phase pad mount distribution transformer has two primary bushings on it. Which of the following is true concerning these bushings?
C) The bushings are both at one end of the primary coil
What rating is required for oil filled sectionalizer to be opened under load?
B) It must have an F-2 rating
What is the primary purpose of fuse coordination?
B) To plan out our system so the least number of customers will be affected by any one outage
What type of system carries large blocks of electrical energy over relatively long
distances?
C) A transmission system
What types of transformers are used in underground primary metering?
C) Both Current transformers & Voltage transformers
What is the most likely cause for a streetlight burning during daylight hours?
A) The photocell has failed
Why is the ground trip block activated prior to switching on the recloser or load relief switching downstream of the recloser?
D) To prevent the recloser from operating due to switching surges that cause an imbalance between one phase and the other two
What should be used to energize and de-energize oil filled equipment?
B) Appropriate insulated sticks
The need for a neutral is minor when the load is balanced among the three
phases. For this reason, the neutral is often omitted in distribution and
transmission wye circuits.
True
What is a method of finding the neutral position on a regulator when there is no other means of identifying the neutral position?
A) Check across the source and load bushings with an approved voltmeter
What is the best rubber cover up component to use to cover up odd shaped conductors and equipment?
D) A rubber-insulating blanket
In a series street light circuit, what is the purpose of the red wire connected to the LSC?
D) It goes to the load
All underground elbows are load break capable up to 100 Amps. Any load
above 100 Amps must be switched out in a switchgear.
False
How many normally closed contactors, are needed to energize two feed wires for a 240-volt street light circuit?
A) Three
An Auto booster is capable of lowering the voltage on a distribution line.
True
If the regulatory tap setting on a single-phase transformer is changed from tap C (100%) to tap D (97.5), what happens to secondary voltage?
A) It will increase
Why are switches installed in distribution feeder circuits?
B) To redirect power flows for load balancing & To sectionalize or isolate a section for repairs
What is the purpose of a sectionalizer?
A) Isolates faults and protects the feeder and distributor
There are two types of distribution regulators now in service. They are the
induction and the step voltage regulators.
True
What is the term to describe a luminous discharge created by the ionization of air surrounding an electrical conductor?
B) Corona
What does the number 25 on a luminaire indicate?
B) 250 watts
Which of the following is true about distribution transformer system voltages taps?
C) Taps connected to the primary winding to broaden the range of system voltages suitable for installation
In a circuit with three lamps in series, what will happen if one lamps filament burns out and becomes open?
D) The other lamps will not be lit
What are substation breakers and reclosers designed to protect?
C) The substation and substation transformer
In the substation part of the distribution protective scheme, the acronym “ACB” stands for automatic circuit breaker.
False
Which of the following is true regarding a three phase delta circuit?
D) All the above
If neutral position on a voltage regulator cannot be determined 100% due to vandalism or loss of other means, the employee should ________ before closing the bypass switches.
D) de-energize the line
What is the safest way of completing electrical distribution work?
C) De-energize, isolate, test, and ground
When paralleling transformers, what is the maximum allowable difference in rated impedance between the transformers?
D) Within 7.5% above or below each other
What is the maximum use voltage for class 2 rubber gloves?
C) 17, 000 volts ac rms
In addition to ensuring percent impedance of one transformer is between 92.5% and 107.5% of the other transformer, which of the following conditions must be met in order to parallel two single-phase transformers for greater capacity?
A) Voltage ratings must be identical and the transformers must be connected to the same primary phase & Tap settings and frequency ratings must be identical
What is the most important article of protection for a lineman or cableman?
C) A good pair of rubber gloves with proper dielectric strength
What are the two types of capacitor banks?
D) Fixed and switched
Each work project and especially those projects requiring linemen and cablemen to handle energized electrical conductors should be planned in detail. What should this
plan ensure?
C) The safety of the workers and the reliability of the electrical service
Reclosers normally operate three times or less to prevent an outage due to a
temporary fault. Which of the following would cause a temporary fault?
D) Phase conductors slapping together & A tree limb brushing against a phase conductor
Why do transmission lines operate at higher voltages?
C) Higher voltages increase the power carrying capacity of the line
You have just de-energized a capacitor bank. How long do you need to wait before applying grounds?
D) 5 minutes
Which of the following is true concerning a transformer with the following voltage rating on the nameplate: 12,470GRDY/7,200?
C) Indicates the transformer has reduced insulation at the neutral end of the primary coil
A transformer has a primary to secondary voltage ratio of 55/2. If the secondary voltage is 480 volts, what is the primary voltage?
C) 13.2 KV
What causes a voltage drop in an electric circuit that causes voltage to be less at the load end than it is at the source end of a line?
C) Current flowing through the line impedance causes a voltage drop
What component is used to regulate voltage on a line when capacitors are no longer effective?
D) All the above
How is voltage regulation on any electrical system defined?
C) The difference in voltage between periods of no load and periods of full load on the system
What type of transformer bank configuration does the following illustration represent?
B) WYE / Delta
A study of 10 linemen who regularly worked on energized 345 KV transmission lines conducted by personnel at John Hopkins University for a 10 year period concluded what about the health of the linemen?
C) The linemen were in excellent health
What must be done to the secondary circuits if a new transformer is to be connected in
parallel with an existing transformer?
C) Phased in with a voltmeter
Which of the following are methods of controlling light emissions from streetlights?
A) Reflectors, refractors and diffusing globes or a combination are used to direct and control light
On a delta circuit, there is no return current through the ground.
True
The magnitude of electric fields at ground level under all overhead transmission lines is
________.
D) very low
What is the purpose of capacitor banks installed on distribution circuits?
B) To improve the power factor
Which of the following is considered to be an inductive load?
D) Motor loads
An “ATO” is strictly for overhead applications and cannot be used in an
underground system due to capacitive charges that build up on underground
cable.
False
The ground strap on a common single-phase pad mount distribution transformer
is connected to one end of the primary coil.
True
What is the maximum use voltage for class 2 rubber gloves?
A) 17, 000 volts ac rms600 volts ac rms
What voltage does a typical single-phase pole mounted transformer feeding residential
customers supply?
A) 120/240
Which of the following is true concerning transformer “polarity?”
A) A comparison of current direction in the primary windings verses the direction of current flow in the secondary windings at a given time
The purpose of a voltage regulator is to maintain a constant voltage on an
alternating current primary distribution circuit with variations in load.
True
In the substation part of the distribution protective scheme, the acronym “ACB” stands for automatic circuit breaker.
False
Each capacitor cell is equipped with a(n) ___________ which de-energizes each cell in about 5 minutes
B) Internal discharge resistor
What is used to cover primary distribution conductors to protect the lineman from an accidental electrical contact?
C) Rubber insulating line hose
What is a method of finding the neutral position on a regulator when there is no other means of identifying the neutral position?
D) Check across the source and load bushings with an approved voltmeter
In a normally closed contactor, when will the contacts be closed?
D) When it is de-energized
You are doing an amp check on 100 KVA CSP because a customer called in and said it was making noise. You get 380 amps on one leg and 406 amps on the other. Is the
transformer overloaded?
B) No but it is real close to being overloaded
What is Quadriplex overhead cable for?
B) Supplying three phase loads
Some large industrial customers may be served directly from the transmission or sub-transmission circuits.
True
What is used to counteract the buildup of capacitive reactance from extra high voltage transmission line circuits when it exceeds the ability of the system to absorb the reactive KVA?
C) Shunt reactors
On a common setup, how many times does a recloser operate before it locks out?
B) 3
In a single phase wye circuit, current flows through the hot conductor and
returns to the source through the neutral.
True
When will a sectionalizer lockout if fault current is present on a branch line?
A) The sectionalizer locks out to isolate the fault when the line is dead, on the third count by the recloser and the sectionalizer
What does the hipot adaptor for phasing sticks allow you to do?
A) It applies a DC voltage on the cable to test them before they are energized
In a series street light circuit, what is the purpose of the red wire connected to the LSC?
D) It goes to the load
What is the most likely cause for a streetlight burning during daylight hours?
B) The photocell has failed
Why is the ground trip block activated prior to switching on the recloser or load relief switching downstream of the recloser?
C) To prevent the recloser from operating due to switching surges that cause an imbalance between one phase and the other two
Reactive kilovolt-amperes can be supplied to the electrical system by connecting
___________ to the distribution circuits in the substations or out on the distribution
lines to neutralize the effect of customer inductive loads.
D) banks of capacitors
A switch cabinet is rated at 600 amps. This means:
C) The switch is rated to carry a maximum of 600 Amps
When you raise a tap setting on a transformer from 3 to 2, you will increase the
voltage.
False
How many times will our field reclosers operate before they lockout?
D) Three operations and then lockout
What piece of equipment is basically a transformer in nature used to improve voltage at or near the end of a primary distribution line?
C) Auto booster
What should be done before replacing a three-phase transformer?
C) Rotation should be checked, marked and returned the same way
What should be used to energize and de-energize oil filled equipment?
D) Appropriate insulated sticks
When putting a regulator back on line, the bypass switch is opened after the source side switch is closed and before the load side switch is closed to energize the neutral indicator, prevent shock to the windings, and to prevent an outage.
False
What are the two main reasons linemen wear safety hard hats?
A) To protect the head from the impact of falling or moving objects and electrical contact
What is the best rubber cover up component to use to cover up odd shaped conductors and equipment?
C) A rubber-insulating blanket
Which type of transformer bank can you install on a four-wire WYE system?
D) All of the above
When changing out a transformer that is paralleled with another transformer, what needs to be done before disconnecting the primary connection with a shotgun or switch
stick?
B) Secondary phase conductors must be disconnected from the transformer
What type of transformer connection is shown in the following illustration?
D) Open Delta – Open Delta
Conductor covers, insulator covers, and cross arm covers are fabricated from rubber
and what other material?
C) High dielectric polyethylene
Phase sequence has no effect on poly-phase motors.
False
What meter would you use at the customers meter housing prior to placing load on it to
ensure that the phase sequence is correct?
A) Rotation Meter
What is the frequency of alternating current generated in the United States and Canada?
C) 60 hertz
How is an insulator hood properly installed?
D) It will overlap the line hose when properly installed
Once secondary phase conductors have been removed from an energized
overhead transformer, they should be considered energized until the connection
status of both ends of the secondary mains are verified open and not paralleled
to another transformer.
True
Class 0 rubber gloves are AC proof tested to __________ volts rms and DC proof tested to __________ volts average
B) 5,000 and 20,000
What component is used to regulate voltage on a line when capacitors are no longer
effective?
D) All the above
On primary metering installations, what is the purpose of current transformers?
B) To take a percentage of the customers load in amps and send it to the meter for measurement
What is the purpose of a sectionalizer?
D) Isolates faults and protects the feeder and distributor
In addition to changing voltage from one level to another; what else do power transformers do?
D) Regulate the voltage level and control the flow of reactive Kilovolt-amperes in the power system
What is the purpose of a sectionalizer?
C) Isolates faults and protects the feeder and distributor
In addition to changing voltage from one level to another; what else do power transformers do?
A) Regulate the voltage level and control the flow of reactive Kilovolt-amperes in the power system
Which type of contactor is normally closed?
B) BB
What is calculated when the resistance, inductive reactance, and capacitive reactance
are considered to determine the total opposition to current in a circuit?
A) Impedance
What type transformer is used in a series street lighting circuit?
C) Constant current
The voltage variation to residences (secondary) has been standardized. What are the
low and high limits?
C) 114 and 126
Each work project and especially those projects requiring linemen and cablemen to handle energized electrical conductors should be planned in detail. What should this plan ensure?
B) The safety of the workers and the reliability of the electrical service
What does protective equipment provide the lineman?
B) A margin of safety for error without injury
At what percentage of coil rating do most reclosers operate?
A) 200%
Why is the neutral floated on a WYE / Delta bank?
D) All of the above
What limits the capacity of overhead AC transmission lines?
A) Thermal expansion and resulting sag of line conductors
Reclosers are installed with _______ switches so that the unit can be taken out of service for maintenance without interrupting power to customers.
A) bypass
What happens to the current on the neutral of a wye system when the loads between
the phases are not balanced?
A) The current goes up on the neutral
Single-phase transformers generally have additive polarity if they meet which of the following conditions?
B) Smaller than 200 KVA and operate at a voltage less than 8,660
You have just de-energized a capacitor bank. How long do you need to wait before
applying grounds?
C) 5 minutes
Why do transmission lines operate at higher voltages?
C) Higher voltages increase the power carrying capacity of the line
The magnitude of electric fields at ground level under all overhead transmission lines is
________.
D) very low
What facility is used to switch generators, equipment and circuits or lines in and out of
the system, change AC voltages from one level to another and/or change alternating
current to direct current or direct current to alternating current?
C) A sub station
What are the two basic checks made after energizing a new capacitor bank to detect
open or defective capacitors or excessive neutral current?
A) Voltage and current readings on each primary lead and neutral
What does the term “CSP” stand for?
B) Completely self-protected
What is the definition of a sectionalizer?
C) A protective device used to sectionalize a branch circuit and works in conjunction with a recloser wired ahead of it
How does a capacitor bank correct the power factor in an area with a large inductive
load?
D) It stores a charge and returns it to the line creating capacitive reactance that aid in correcting the power factor
The need for a neutral is minor when the load is balanced among the three
phases. For this reason, the neutral is often omitted in distribution and
transmission wye circuits.
True
What type of fuse limits the magnitude of current flow by introducing a high resistance
after the fuse element melts?
B) Current-limiting Fuse
Substation disconnect switches are designed to interrupt charging current and
full load current with no modifications or specific designs.
False
In distribution substations, what regulates the substation bus voltage?
C) Power transformers equipped for voltage regulation
Which of the following statements is true concerning a WYE / Delta Bank with the center can center tapped to provide single-phase loads?
B) The lighter can caries 2/3 of the single-phase load and the two power pots the other 1/3 of the single phase load
Why do transmission substations contain equipment used to sectionalize the electric
transmission system when a fault or short circuit develops on one of the circuits?
B) The defective circuit is switched out automatically protecting the remaining portion of the transmission network from trouble
When removing an electronic recloser from service, for maintenance, what must you
do before closing the bypass switches?
C) Block ground trip
In addition to a position indicator that shows tap position, what does our step voltage
regulators have to indicate the neutral position?
C) A neutral light
What does the term “ATO” stand for?
B) Automatic throw-over
When will the sectionalizer only count?
A) When the recloser momentarily opens and de-energizes the line
What is the purpose of an ATO?
A) Switches customer’s supply feed from one source to another without interruption of power in the event of loss of primary feed
A 20 KVA transformer has a ratio of 55 to 1. If the primary voltage is 13,200, what is
the voltage at the secondary?
B) 240 volts
While phasing two secondary circuits, what should the employee do after getting a zero
reading?
D) Check the meter on a known source to validate the meter
Regulators have tap position indicators that use either a gauge or a light to
indicate the neutral position.
True
What does the L shaped lever on a hydraulic recloser do?
D) Sets recloser for non-reclosing or normal mode
Which of the following is a principle function of reclosers?
D) All of the above
What is the function of a distribution transformer?
B) Reduce the voltage in the primary circuit to the utilization voltage required by the customer
When a fault occurs beyond a sectionalizer that is of a permanent nature, the
sectionalizer will lock out immediately to protect the system.
False
What is the polarity of the transformer illustrated below?
D) Subtractive
On primary metering installations, what are voltage transformers used for?
A) To proportionally reduce the voltage to a measurable value