1
Q
A
13,800 V 25,000V 115 KV 230 KV 345 KV
2
Q
2)-What is the difference between a radio 5K circuit and a network 5K circuit?
A
Hey 5KV radio circuit has one source station and therefore feed only in one direction 85KV networks Circuit feeds from to source stations most commonly referred to P and use primary Netwerk units giving it a two way feed
3
Q
3)-From the appropriate prints examiner will ask you to identify and explain the different lines and symbols of each of the following 15 KV circuit print 5KV circuit print secondary sheet secondary network sheet construction sketch Netwerk feeder
A
Go to the prints
4
Q
4)-Describe the secondary networks system from the substation to the customer service.
A
The secondary Network Systems supplied via 13,800 volts networks feeders which originate from one of six networks substations station 2,12 ,53 ,71 ,492 and 514 the feeders supply network transformers in either a secondary Netwerk vault or tertiary network vault voltage is step down to one 120/208 or 277 /480 V it is then distributed normally by 4/0 seven wire mains or 500 MCM 4 wire main through manholes and eventually to the customers prem
5
Q
6)-Describe the method of numbering DSS lines
A
DSS lines the number of the station that is being supplied followed by a hyphen, after the hyphen , lines under 19,999 V will be numbered 51 through 299, or 1000 through 1999 with the voltage identification number 1 directly following the hyphen lines from 20,000 to 29,999 will have a four digit number directly following the hyphen the first digit being 2
6
Q
Describe the method of numbering 5kVA Distribution circuit
A
5KV Distribution circuit numbered for the station where they originate followed by a hyphen, the number of the Circuit assigned 1 through 24 distribution Circuits, 25 to 50 are series circuits .th hyphen is iomitted when the originating station is only two digit. Between primary Netwerk units (PNU) identify with the letter N between the PNU numbers ( lowest number first, highest number second)
7
Q
4)-Describe the method of number in Cambridge lines
A
800 series are reserved for the Cambridge DSS lines
8
Q
A
120/208 volts and 277/480 volts
9
Q
###7)-Identify the following a 126–04 B 3606 C 101–104 D875-1312 E 2–1n33 F 292-h7 G 6 N 7 H 110-2211
A
A 5KV radio distribution circuit B 5KV radio distribution Circuit C 15 KV distribution system supply line
D 15 KV Cambridge Distribution system supply line
E 15 KV secondary Netwerk Feeder
F 15 KV distribution Circuit
G 5K the primary Netwerk Circuit
H 25KV distribution system supply line
10
Q
A
A system change notice is the form used to notify the system operator of any changes on the system. It is required when new or changes of equipment are connected to the system that were not already documented. Normally system changes are communicated through the permit process and documented. When work is performed outside the permit process the system change notice services to update the records for the system operator and is required . (See(OG-3B)
11
Q
A 5Kv
B 15 KV
C 25KV
A
A 4160 V, 2400 V
B 13800 volts, 7960 V
C 24,000 V, 13,870 V
12
Q
10 how are the individual phases of a circuit identified?
A
A)5K V phases A-B-C and system ground (D leg)
B)15 KV phases A-B-C
C)25KV phase C-A-B
13
Q
11) to what conductors of a 5KV circuit are the single phase leads of a transformer connected?
A
There are three possible combinations
A system ground (D-leg)
B system ground (D-leg)
C system ground (D-leg)
14
Q
12 ) to work conductors of a 5KV circuit are three phase transformers connected for the following installations :
- conventional transformer
- Fuse typed transformer
- padmount transformer
A
A )conventional transformers A-B-Cphase wires only NO D-leg connection
B) Fused type transformers
A-system ground B-system ground C-system ground
(three individual ground required for each transformer)
C) pad mount transformers A-B-C only ;with bonding to system ground and a driven ground rod
15
Q
A
Clerance- will be given when a zone of protection can be established :using visible brakes and grounds surrounding the work area .clearance tags are applied to all open points of known sources
and caution tags applied to identify devices in off schedule position
16
Q
A
Permission is given when a zone of protection is established .
- without visible breaks
- grounds are not installed surrounding the work area.
work must be tested deenergize and performed using live line methods
17
Q
A
Construction tags
are white tags
they shall be installed on new Eversourse equipment or new customer equipment during the construction.
That is not under the jurisdiction of the system operator
a caution tag is required at the disconnect point of demarcation between the construction and the equipment under the jurisdiction of the system operator
18
Q
14)explain what disconnection of ground you would expect to have between a live bus and your work in the street on a circuit which has been Deenergize and tag buy you A)-5K V distribution circuit
A
A) 5KV distribution Circuit :
The Zone of protection will be established by
opening all devices surrounding the work
-installing permission tags on all known sources
- caution tags will be use on all open points that are not known sources and devices that are off schedule
19
Q
14)- B15 KV Distribution circuit
A
15 kVA Distribution circuit: the zone of protection will be established by
opening devices surrounding the work area and installing Clerance tags
grounds will be installed at the closest point of the work to be performed when practical
20
Q
14)-C secondary Netwerk feeder
A
C)-secondary network feeder
-all protectors will be confirmed open by testing the feeder dead back
-primary switches will be confirmed in the ground position at the closest point surrounding the work area and the feeder will be grounded at the station cubicle
#stations go to primary switch and verified#
21
Q
15)-Explain the rubber glove rule as it pertains to the underground
A
Protective gloves are required as directed in the employee safety manual (section 8.5 sub par a - M)
-class 1 gloves are required for liveline method on four KV circuits
-class 2 gloves are required -when employees are operating 5KV oil switches remotely
-gloves required “lock door to lock door” for energize switchgear or enclosures -when employees are working on secondary cable that is or may become energized at 50 V or above
-when using or holding any test equipment that is or may Become energize at 50 volts ir above
explained are listed in section 8–5.2 subpar A- F
22
Q
16) what protective clothes are required when performing switching operations on pad mount equipment
A
Hardhat
- 40 cal switching coat and coveralls
- rubber gloves
- safety glasses
- arc rated face shield
23
Q
17)-how are fall indicators identified on a circuit print?
A
A) FA auto reset type
B) FM manual reset
24
Q
18)-what side of the switch would fall indicators be installed on?
A
Fall indicators should be placed on the load side of the switch
25
19)-what protective clothes are required to operate a 5KV oil switch in a manhole?
- Hardhat
- 40 Cal switching jacket and coveralls
- rubber gloves class 2
- safety glasses
- hooded arc rated face shield
26
###20)-explain what each of the characters in the network feeder; 53 –1N 24 refers to
```
53-53rd station feed
1- 13,800 volts
N- Network
2 - bus section 2
4 - cubicle#4
```
27
21)-who should be notified before taking an unscheduled outage?
You should notify your immediate supervisor or the control desk and assistant system operator .
(system operator will send out a customer blast to notify of outage)
28
22)-explain the procedure for proving cable and equipment deenergized
You should exhaust all available identification resources using applicable documents and devices
and cut to prove using grounded cutters from a remote location
29
###23)- what are ARD’s? What do they do?
Automatic reclosing devices.
- they react to the fault current .
- opening upon seeing fault current and then will reclosing after a specific number of times.(usually once in the underground)
- if the fault has cleared the circuit will reclose and staying in
- If the fault is still present the Circuit will reclose, see the fault reopen and lockout (overhead typically is three) (times and typically 10 second delay)
30
What is a VP1
VP1 is a voltage probe indicator.
direct contact voltage detector
- indicates voltage present greater than 50 VAC up to 600v
31
What is a tic tracer
- Tic tracer can be used on a bare conductor and a capacitive test point
- it has two settings the lowest setting detects voltage between 24 V and above the high setting detects 1000 V and above
32
Explain what wiggy’s are?
- Wiggies can be used on bare conductor only.
| - it detects voltage between 120 V and 600 V
33
What is a LV-5?
The LV-5( low voltage detector )
-is a handheld direct contact tool
-capable of detecting voltage present as low as 5 V
(LV -5S is similar and use for stray coltage) detection
34
What is the HD Mark 5?
HD Mark 5 is also known as the 5/15 meter
-it is a meter used on bare conductor only
It can detect voltage from 1000 V to 15,000 V
-it can be used for phase to ground as well as phase to phase measurements
35
What is a HD proof tester?
The HD proof tester is an instrument that can be used to test the 5/15 phasing meter ,before and after the actual testing of the equipment in question ,in the event that there is no known energize source available
36
What is the HD DVM 5–3
It is a three phase voltmeter (Hayhurst box )
- it is a direct contact inductive device used to identify voltage present on the 5KV system
- it is designed to be applied on Deenergize cable and read tested results from a remote location went energized
37
What is a HD PB 300?
The PB 300 phasing meter also known as the Shannon box
- is an inductive noncontact test device
- used to compare phases of energize cable on the 5KV system
- it is designed to be applied on deenergize cable and read test results with remote location when energized
38
What is a fluke amp meter?
The combination volt/amp meter( fluke )
- is a direct contact positive digital test device
- can be used to take voltage or load readings
- it is not the preferred device for phase bank applications and is limited to 600 V AC
39
What is the multimeter ?(Simpson, triplet)
The multimeter is used on bare conductor only
for voltage measurements.
-it is very accurate and is the preferred instrument for taking secondary readings .
-models different but usually the voltage range is from 0 to 1000 V AC
-the multimeter also is capable of measuring DC voltage and resistance
40
25)-Explain or demonstrate the use the Bierer phasing tool in the following applications a cable identification :
of a
-distribution system supply line
- Tool sends Test current for phase and cable Identification. -grounds are applied beyond the point of identification and Sender ( Bierer tool) is applied before the point to be identified .
- test current is read by portable CT to obtain clear identification of test current signal on all conductors to be identified .CT is directional as required the user to apply it in the intended direction
41
25)-Explain or demonstrate the use of the bierer phasing tool on how to :
identify a 13.8 kv network feeder
Multiple grounds may be applied and the test current (Beirer tool )is applied ,signal loss may be experienced .
- the device can be applied independent of ground return -the test current can be sent out on two phases and returned on the third
- CT is directional and requires the use it to apply it in the intended direction
42
26 )-what can happen if a generator is connected to the system ?and how are the hazards medicated ?
A)customer owned
B)Eversourse installed
Normally any generator that is permanantly attached to customer service is equipped with a disconnect /throw over switch .which prohibits tying a generator into our system .
-however if a customer improperly attaches a generator without opening his main disconnect a possibility exists that the generator voltage usually (120/240) could be transferred onto our system and normal step down transformer would act as a step up transformer and deliver primary voltage into a system that we believe to be deenergized.
Standard W5114 in process
43
27)-Who is responsible for phasing on a 5KV circuit? Who must prove and discharge the cable after live phasing?
The delegate in charge is responsible for the correct phasing of a 5K be distribution Circuit this is typically the construction inspector but maybe another qualified and authorize employee such as a trouble Shooter.
Responsibility for properly marking and then discharge the cable vefore any work xan be preformed
44
28 )-what are the two main types of 600 dead break elbows in use on our system ?explain how they are similar or different in respect to the following:
installation
and removal
The two main type of 600 amp Elbows used in our system are the
-Visibreak elbow system with the multi lamb connector
-the T-OP 11 system which utilizes the LRTP.
A)-the two assemblies totally different.
the components of the T-OP11 include cable adapter. connector, LRTP and housing .
the visibreak consist of cable adapter, connector, contact tube, multilamb and housing with 200 amp interface .
-virtually no parts of this is compatible with each other.
visibreak is easily identified by orange band around the T- body .
B)-on the visibreak elbow ,a different wrench is required for both construction or installation and removal .
-The T-OP11 utilize the same wrench to perform both function .the T-OP 11 elbow also requires the preliminary installation of a brass threaded male insert into the apparatus bushing of the equipment to be used . short of brass fitting should be securely tightened into the bushing.
45
29)-Explain the applications and requirements for the “yellow streamer”
Identifies that a potential hazard exists within the underground location.all locations identified with the “yellow streamer” is Shall be recorded in the “manhole/substation” tracking system via the ad YS,”circuit open/reclose” feature.any contractor or employee encountering a yellow streamers shall contact the operation supervisor and their immediate supervisor to determine the potential hazard locations marked with “caution do not enter” shall not be entered until the potential hazard has been properly evaluated repaired or made safe so others can work safely there .if a yellow streamer is identified by Dispatch by a physical stream is missing it shall be replaced at that time (W1006 – see section 9.5.1through9.10 for process information)
46
30)-Name three instruments that can be used on a capacitive test point
Three capacitive Test instruments are
A)tic tracer
B)-VP – 1
C)– LV-5
47
31)-What visibly distinguishes a 5K the heat shrink joint from a 15 KV heat shrink Street joint?
5KV heat shrink joints have a smooth one piece outerjacket sleeve with a 2 inch white band install somewhere over it.
15 KV heat shrink joints has a split outer jacket sleeve with a steel channel holding it together
the surface of the 15 KV joint also had very rough surface similar to alligator skin
48
32)-What is a visible break and where are they used?
A visible break is a disconnected device that provides clear access to view the spatial relationship between the energize parts and the Deenergize parts they are required when establish in Zone of protection on a 15 KV radial system.
they include load break switches with viewing ports,fuses, 200amp and 600 amp elbows
49
What is a 600 amp parking bushing
600 amp parking bushing is an insulated standoff that can be mounted on a retaining clip to provide stationary support of 600 and elbows in an open position and keep available access for future testing by removal of the Installed on a 200 amp port
50
What is a feedthrough bushing
A feed through bushing is a two-bushing piece of equipment used in conjunction with a 200 amp load break elbows. it has a common bus and it is used mainly to provide a test or access port for grounding, testing ,phasing or connecting cable terminated in a 200 amp elbow
51
What is a switching station (turtle, CSS, equipment cabinet )
A switching station is a piece of equipment usually found in the URD area .It is surface mounted and contained 200 amp load break elbow junctions normally one set of elbows is in the standoff and can be used as a tie if necessary
52
What is an insulating protective cap
The insulating protective cap is a term usually given to a premolded cap used to cover expose 200 amp and 600 amp bushings. 600 amp caps require a threaded stud . They both require the use of a hot stick for installation and removal And must be installed on bushings that are or may become energized
53
What is a LRTP
The LRTP stands for load reducing tap plug and is a component in a 600 amp T-OP 11 elbow system
54
34)-What are PCBs? Where are they found and how can they become airborne? How are they classified? how are they treated if level is unknown?
PCB is an acronym for polychlorinated biphenyls a compound found an older insulating oil. it can be found in any oil filled device .it has been shown to be harmless unless it becomes airborne, igniting material containing PCBs is the only way for the substance to become airborne.
PCB is classified into three levels
1)-0 to 49 PPM = non-PCBs
2)- 50 to 499 = PCB contaminated
3)-500 ppm and above are PCBs
-If level is unknown the universal precaution should be exercised and oil should be treated as pure PCBs until tests confirm or reclassifying material. respiration is required only when PCBs have become airborne
55
35)-What does URD stand for?
URD stand for underground residential development (defined in optimal design guidelines updated 10 -11–2012)
56
36)-Will a duck Bank of 4 that leaves a manhole 2 over 2 always enter the next man hole in the same configuration?
No it is a common occurrence for the ducts to transpose from one manhole to the next ,it is also common to have only part of a group of ducts break out into a manhole
57
37)-When breaking down of 5 kV heat shrink joint, the other jacketing sleeve and Braid have been removed. Visible is a thin black tube. Is this to be semi-conductive tube or a stress control tube?
The first visible tube is a semi conductive tube. The stress control tube is normally the first you’ve applied on a 15 KV joint and Would neither be visible or present on a 5KV joint.
58
38)-Explain how the cable should be prepared and how the material should be applied when installing lead sheath repair ( epoxy type)?
The following steps should be followed when applying a “stop it “repair patch:
A)-identify and confirm Deenergize If 5 KV,Deenergize and ground if 15 KV
B)-clean damaged area
C)- Roughen surface
D)-apply Rubber tape water barrier
E)-clean lead sheet with Solvent
F)-apply “stop it”
1)-immersed in water for 5 seconds
2)-half lap and entire roll overprepared lead sheath
3)-smooth and press the resin into patch until adhesive is no longer Tacky
59
###39)-When giving or confirming a switching order, what are the only “action “words acceptable and how is the order communicated and carried out?
Only the words “open” and “closed “ are acceptable.
All switching orders will be given and received using 3 part communication and carried out by following the 6 steps of perfect field switching
60
40)-When taking voltage measurements at customer service entrance, what instruments are approved for use, what instrument should not be used and whom should findings be reported?
Digital volt meters(fluke) or analog multimeter are acceptable devices. Solenoid or “wiggy’s” are not acceptable for reporting accurate voltage measurements. Voltage measurement should be reported to the system operator.
61
42)-Identify and describe the five basic components of the elastomer disconnect of splice.
The five basic components of the elastamold disconnectable splice Are;
1) -center housing - I, Y or H
2) -straight insulating receptacle
3) -cable adapter
4) -conductor contact (connector )
5) -clamp
62
43)-Is it possible to drop off a tap from an Elastamold Y splice without dismantling the entire joint? If so, describe the entire process.
Yes, the tap cable or any cable from an Elastamold disconnect able splice can easily be removed. You would first tested capacitive Test point, if this indicate a deenergize reading you would then through the molded test port. The straight insulating receptacle could then be removed with the sleeve pulling Tool, the hylug would be removed from the center housing and a dead end cap Could be installed on the exposed port.
63
44)-Explain in demonstrate the proper use of phase identification tool such as a, Timco impulse phaser or a bearer phasing tool in the following situation :
A)- identification of one single conductor concentric cable in a trench
B)-identification of three single conductor cable
C)-identification of three conductor Cable
D )-phasing of three single conductor cable
A)- Obtain Clearance to work. -Prove deenergize,
-apply grounds at one end. -Apply test current at opposite end.
-Detect test current with portable CT device in the trench.
-May need to isolate consentric cable from system ground to obtain clear results.
-Verify by using an amp meter or other approve devices if cables in trench are carrying load.
B)-obtain Clearance to work. -Prove the energized.
-Applied tool at available cable end, (stations, p.m., etc. )
-adjust sensitivity of receiver to lowest discernible setting and lock adjustments.
-Identify cable with receiver using arrow indicator towards ground to apply CT clamp. -Send test current out on phase 1 and 2and return on phase 3 if multiple grounds reduce signal.
C)-same as B except sheath return is required to obtain clear indication
64
45)-At what frequency does the electric distribution system operate?
The electric distribution system operates at 60 Hz or 60 cycle per second.
65
```
46)-What is the minimum approach distance for the primary cabinets of a live front :
A)-three phase 15 KV
B)- three phase 5KV
C)- 277-480VAC secondary
D)-120-208 VAC secondary
```
```
Minimum approach distance is;
A)-2’2”
B)- 2’2”
C )-1 ft
D)-avoid contact
```
66
47)-What is the difference between direct current and alternating current?
AC is an alternating current and continuously changes, DC is a constant and is directional.
67
###48)-What is resistance?
Resistance is the opposition to the flow of current.
68
49)-What is a capacitor?
A capacitor is something that can hold the charge ( battery, cable ect)
69
50)-What is a fuse?
Hey fuse is electrical safety device to operates to provide over current protection of an electrical circuit.
70
51)-When taking a current reading on a 120/240 V AC service explain the following :
A)-what is expected to return on the neutral if 25 A and 30 A are observed on the high side?
B)-25 A and 12 A are absorbed on the high side and 0 A on a neutral.
A)- 5 A would be expected to return.
| B)-current is not returning properly and she immediately be investigated and rectified.
71
52)-What is a kilowatt?
A kilowatt is 1000 Watts
72
53)When taking readings on a three wire Delta service, You obtain the following readings below. What does this indicate?
240 V to ground
240 V to ground
0volts to ground
240-240–0 phase to ground reading indicates a grounded leg .(zero potential to ground is the grounded leg )
73
54)-And what terms of Transformers rated?
Transformers are rated at KVA
74
###55)-Draw the schematic diagram of the following transformers showing phase-to-phase and phase to ground voltage:
A)-single phase conventional B)-single phase fuse
C)-three phase straight 240 D)-3 phase 120/208
Draw a diagram of these four things
75
56)-When installing three 167 kVA single phase fuse type transformers in the Y configuration what grounding is required for primary and secondary connections?
- 10 foot grounding bus must be installed.
- Primary and secondary neutral connections must be connected to the system ground.
- Secondary will be 2–500 MCM cables from each transformer to ground bus.
- Neutral crab to be connected to common bus neutral.
- The primary grounding is provided by three individual 1/0 bonds from the transformers to bond frame.
- Bond frame to be connected to a common neutral bus( see construction standards see 3905 )
76
57)-A 50 kVA single phase transformer that is 120/240 V secondary has a balance load of 250 A per side .is this transformer overloaded? If so by how much?
Yes it is, by 10 kVA (500×.12 equals 60 kVA )
77
58)-after transferring the load of a single phase transformer to a 100 kVA single phase transformer, load readings are taken on the secondary side of the 100 kVA transformer. These readings are 500 A on one side and 300 A on the other side is this transformer overloaded?
The KVA loading is okay, but the unbalanced load on the secondaries should be addressed. ( 500+300) X .12=800
800×.12 =96 kVA
78
59)-What is the construction standards for installing fuse type transformers in the following applications?
A)-single phase application
b)-three phase application
A)- 3900
| B)-3905
79
###60)-When connecting transformers to the system what must be connected first and why?
The ground must be the first thing connected and the last thing removed. Transformer primary windings terminate to the case of the transformers which would become energize to the full voltage if not grounded.
80
61)-Explain how to connect individual single phase transformers in the following configurations. Be sure to include the face-to-face and phase to ground voltages that will be achieved.
A )-delta
B)-Wye
C)-Open Delta
Draw a diagram for
delta
wye
and open delta
81
62)-How are the secondary neutrals of each of the above transformers configured treated?
A delta
B eye
A)-Delta has no ground
| B) Wye transformer neutral tied to system ground
82
63)-Why are the primary leads of the transformer smaller than the secondary leads?
The higher the voltage the lesser the current, the smaller the cable needed. The lower the voltage the higher the current, the larger the cable needed.
83
```
###64)-What factors should be considered before banking two of the following transformers together:
A) 2 single phase transformers B)-2. phase transformers
```
Banking transformer:
A)-single phase – voltage, impedance
B)- 3 phase – voltage, impedance, manufacturers nameplate information.
84
65)-Is it necessary to bank the secondary of 2 3phase transformers each with 480 V or above secondaries? How would you perform this work?
You would use a multimeter which is able to handle readings of 1000 V. Connecting underrated devices and series is not acceptable.
85
66)-Explain the function of the “under oil switches” ina three phase pad mounted transformer.
“ under oil switches” are required on all newly installed three phase pad mounted equipment after 2015. These switches are gang operated load break devices that can be used to De-energize the transformer or redirect or isolate the 200 amp bushings ( seetechnical bulletin TN015 )
86
67)-Demonstrate the procedure for banking two of the following transformers in multiple:
A)-2 single phase fuse type transformers
B)-3 phase 240 V
C)- 120/240 transformer
A )-fuse type –
-check impedance,
-secondary and primary voltage,
-change primary ratio if needed,
-check or replace fuse for primary voltage,
-Tie neutrals together
-energize take secondary readings,
-bank and pick out pairs.
B)- 3phase 240 V –
-check impedance, check manufacturer name Plate, - check secondary and primary voltage
-energized
-connect temporary Lead between transformers,
-bank remaining leads (if not possible reposition temp lead)
C)-Three phase 120/208
-Check impedance, - check manufacturer name plate, - -check primary and secondary voltage
- connect neutral
-energized
-bank and pick out pairs
-Mark cables
87
68)-How do you load brakes which is installed on three phase Transformers:
A)-De-energize the secondary side of the transformer?
B)- provide alternate source? C)- De-energize elbows?
Load brake switches installed on three phase transformers: A)- isolate the primary winding by opening the TX.
B)- provide alternate supply if installed as one side normally open.
use appropriate A or B load brake switch for Alternate feed.
C )-may not D energize the elbow .
this is a Dependant on the source and load side configuration at the location. radio feed location would De-energize the elbows on the load side of A or B load break is open .
interrupting source Side load brake switch would also deenergize the transformer
88
###69)-What is a dual ratio transformer? At what voltage does it confused?
A dual ratio transformer is a transformer they can operate with the source voltage of 2400–4160 or 7960–13800 V simply by operating the selector switch on the transformer to the desired voltage. The primary voltage can change without affecting the secondary voltage.a dual ratio transformer comes set and fuse at the higher voltage 7960–13,800 V if the transformer is operated at 2400–4160 V both the tap setting and the fuse must be changed the transformer must be energized to change the tap setting.
89
70)- A 3 phase main will be installed and transformers have arrived on site. Two transformers have an impedance of 3.2 ohms and the third has an impedance of 3.4 ohms what is required and why?
Transformers are outside of the acceptable range for banking. Transformers must be within .1 ohms impedance and one or both must be changed with properly paired units (C3905 )
90
###71)-Explain the difference between a “dead front “and a “live front “transformer.
- The term dead front and live front. Refer to the primary side of the pad mount transformer.
- Live front transformers have expose primary conductor most typically are either bolted connections or arc stranglers. -
- Dead from transformers have no expose primary conductors. Cables terminate enter each 200 amp or 600 amp elbows
91
72)-Describe the installation and hook up of an 8Kv single phase 100 KVA fused underground transformer .
connected by the following
A)-12/240V single phase
B)-delta three phase
C)-120/240V Wye three phase include prerequisites grounding fusing an initial pick up in your explanation
Drawn it out
92
73 refer to attachment a an answer questions
Attachment a answer questions
93
```
###74)-You’re replacing a section of 5KV cable between two manholes the circuit consists of three single conductor cables with no taps off either manhole .
how would you maintain a determined phase relation if :
A)all cables are burnt off in the section is between line switches
B)the section is on a dead end tap
C )-no cables are burnt off and the section between lines switches
```
A)-cut off and replace section ,complete jointing in one manhole. Install live rubber caps on both sets of cables in another manhole. Energized, live phase, Mark, De-energized, and complete jointing by marks.
B)-cut off and replace section complete jointing in one manhole and second manhole make up one joint permanent and two temp joints. energize check three phase rotation. If OK deenergize make all joints permanent. If not deenergize and swap 2 temp two and make joints permanent.
C)-in one manhole mark cables in two locations cut all cables between marks.
-the second manhole cut cable off one at a time transfer the marks via telephone from the first man home. Continue cutting in marking only one cable at a time.
replace cable. Phone out and Mark new section of the cable. Connect by marks or existing cable. Use the reverse roll transfer method to ensure correct marks were placed.
94
75. How would you phase 2. 5KV circuits in a manhole that are fed from the same bus?
clear and make live rubber caps on both sets of cables to be phased. energize cables and conduct Tests with appropriate live- phasing device (HD mark 5,PB 300 phase locks) Mark Cable Deenergize circuit and make up joints by marks.
95
76)-Refer to the one line diagram provided on attachment a identify what the devices are at SPP 112/15, SPP 112/16 and SPP 112/17
These devices are overhead “step down” transformer phase A,B and C
they step down to 13.8 kv voltage to 4K V
96
77)-Demonstrating explain the use and safe operation of the following types of switches devices:
A)-G&W fuse cut outs
B)-600 amp padmounted oil switch
C)- 400 amp underground oil switch
A)-The G&Woil fuse cut out is a simple pole oil switch disconnect device it is a small steel cast tank with removable fuses carrier that acts as a cover and a switchblade these devices can be gang operated if linked together with an external component must be deenergize for operation
B)-600 amp PadMount Oil switch has a line side( A and B)switch which may be either bolted connections or 600 amp dead break elbows , and a load side which may be either 200 amp load break elbows or fuse taps
C)-the 400 amp underground oil switch is found in retrofitted and non-retrofitted configuration. not retrofitted units must be De-energized for operation and operated remotely by positioning a ladder to move the handle.
- retrofitted units must be open or closed from outside the manhole with a specific design equipment (stick ,shield, handle and blanket) and can be operated while energized
97
78)-Suppose you have a spicers working on a primary circuit and three different locations between 2 open line switches. The load ahead was being carried by means of a tie switch to another circuit. In between the open lines switches on the portion of the circuit you working on there is several single-phase transformers connected. At the completion of your work the section is reenenergized by closing both switches and the proper manner. One or both‘s circuits trip out due to an out of phase condition .describe what checks and test you would make to to the cond condition (refer to the diagram)
Reopen the line switches in both manholes and isolate work locations. Recheck the marks in all work holes. If no apparent trouble is found, cut and cap primaries in one work hole.Reenergize and live face.
98
79)-Using the following diagrams what is the effect of the indication open 5KB cable on the secondary reading that will be obtained in each of the following examples?
A)-on the three phase delta transformer if the C phase is open?
B)-on the single phase transformer if the C phase is open?
C)- on a wye transformer with C phase open?
A)- you will get no true 240 voltage reading on the three phase
B)-you’ll get no voltage reading on the single phase secondary. C)-your three phase reading will be erratic.
99
80.)-Explain the purpose and function of the following underground devices :
A) -LB or load break device
B)- VFI or vacuum Fault Interrupter device
A the load break device (LB)can be operated energized to break or pick up load ,it is not intended to be close into a suspected fault.
Bthe VFI or vacuum fault interrupter is also a load break device but it is capable of opening on the specific limits. this device can be close in suspected faults for fault location purposes.
100
81. Explain what equipment is required to operate the following device:
A)-elastamold 4K underground switch
B)-G&W trident 4 kv underground switch
C)-which parts are interchangeable?
Devices:
A)-gray box for elastamold switch only
B)-blue box for G&W “trident” switch
C)-there are no interchangeable parts.
101
82)-explain the term “trip setting “in relationship to an underground VF I switch
“Trip setting “is the pre-set amperage amount that will cause the switch to open when be reached.
102
###83)-Explain the typical process used to tie through a 5KV oil switch ( marking, phasing, jointing, etc. ). Include PPE and safe practices.
Under normal conditions if a switch is to be tied through on a permit or emergency, there should be no need to take live phasing, you should be able to accomplish the replacement without marks.
A)-trace and Mark all cables one, two, and 3 a clear distance from the anticipated new connection point .
B)-cut this switch off
C)-rack the cable into proper position
D)-connect the lead in the manhole by the Mark‘s ,jointing will be determined by the number taps feeding from the manhole. If Varnish Cambric switch leads will be used, new joints will be oil stop joints.
103
###84)-Use the given 5K print identify one of each of the following switches:( use attachment B and attachment I )
- tie switch
- line switch
- ring switch
- feeder switch
- internal tie switch
- retrofited oil switch
- VFI switch
- Elastamold /G&W switch disabled VFI switch
Refer to attachment B and attachment I
104
###85)-How are 400 amp oil switches in manholes identified if there are more than one in the same manhole? What position should the switch handle be for a 400 amp oil switch to be in the
A) open position
B)-close position
If there is more than one oil switch in the manhole they will be designated by “N “and “S”for north and south “E”and “W”for East ir West
A)-5o’clock for open
B)-7 o’clock for closed
105
###86)-What type of disconnects would you expect to find on a map installation?
Fused cut outs
106
87)-describe an Demonstrate the use an operation of the Cooper padmount recloser.
A)-describe his purpose in distributive generation (DG)installation
B)-how is a controlled by the field operator?
C)-what needs to be done to apply Test current (Thumper or Kenatron)?
D)-What makes the unit inoperable?
A)-it is used to prevent back feed from distributive generation customers when the source is deenergized by planned work, faulted lines, or abnormal conditions. It senses voltage presence and it will open on loss of voltage on one or more phases.
B)-it is controlled by the form 6 controller which is supplied by a potential transformer for operation and battery maintenance. Can be trip open by hot stick operation
C)- the potential transformer must be isolated from the line. This can be done by utilizing the PT switch or testing the 600amp elbows deenergize and and placing the them in parking bushings.
D)-the “trip” handle will open and prevent closing of the device .the “hotline tag “will also provide closing if enable but it is not intended to be used for lockout operation .
(must be turned off to return the unit to normal operation)
107
88)-Explain what a “one line diagram “is
A “one line diagram “shows only the main line of a circuit including only line and tie switches it does not include Distribution or devices such as transformers in other equipment.
108
89. Explain the function of a three-way or four-way load break switch junction and a standoff bushing associated with it.
The three or four way load break Junction is nothing more than a common bus with either three or four 200 amp bushing receptacles attached .it is utilize in URD switching stations, CST manholes and in conjunction with the new single fused type transformers. If you have to remove a piece of equipment from service you would be able to remove an elbow under load and place it into one of the two standoff bushings that Is provided. operation of a 200 amp elbow is a switching operation!
109
90)-Use a given permit, print and follow sheet; (permit will have a minimum of five switching operations)
A)-explain the mark off on print the isolation limits
B)-find the location of the work manhole(s) on the print
C)-identify jointing to be done under normal
Hands-on provide a permit that contains as many different switching operations as possible attachment P for a B and C
110
91)-What is a G & W oil fuse cut out?(includes safe practices and PPE in your answer)
A)-how is it operated?
B)-explain and demonstrate the proper procedure for changing and checking for a blown fuse.
A G&Woil fuse cut out is a single phase oil filled fuse disconnect device used on our 5KV distribution system. It is usually used in gang of three offering fuse protective to customer own transformers.
A)-all G&W oil fuse cut outs are operated manually and Deenergize from a remote location. the cap-nut must be loosened on all three disconnects and actuating handle is then operated opening (or closing) all three disconnects at once. this handle is usually found outside the vault or structure containing the disconnects and may be accessed by means of special key. Proper PPE includes hood ,glasses ,gloves ,40 Cal switching gear ,and safety shoes.
B) before checking or changing a fuse ,the disconnects must first be open. Only at this time may you proceed .once opening the cap-but it backed off all the way and the entire top attached inner assembly will remove .if a fuse is found blown the fuses in all three disconnects should be changed. Fuses should be threaded into the fuse holder and hand tightened only .the condition of the oil should be noted when changing or checking the fuse.
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