Miscellaneous

Question 1

What is the equation to find Voltage?

Answer 1

E = I x R

Question 2

What are the polarity bushing markings of a transformer?

Answer 2

H1 - X1

Question 3

Describe Impedance

Answer 3

Opposition to current flow in an AC Circuit

Question 4

What best describes transfer of energy in a transformer?

Answer 4

Mutual Inductance

Question 5

What is the difference between a no-load and a load-tap changer?

Answer 5

Requires the transformer to be de-energized

Question 6

What is the difference between AC and DC?

Answer 6

DC has a fixed polarity and AC does not

Question 7

If the high voltage rating of a transformer nameplate read 12000 / 20780 WYE, what voltage would the transformer need across H1 - H2?

Answer 7

12,000

Question 8

What is the rule of thumb for a 240V single phase transformer?

Answer 8

4A per kVA

Question 9

Describe how a transformer works

Answer 9

Voltage is induced when a magnetic field moves across a secondary winding

Question 10

What does a vector represent?

Answer 10

Magnitude and angle

Question 11

What are the SCE Bulk Transmission voltages?

Answer 11

500kV and 220kV

Question 12

What is measured in Ohms?

Answer 12

Impedance, Resistance and Reactance

Question 13

What best describes the difference between AC and DC electricity

Answer 13

AC polarity alternates, while DC polarity does not

Question 14

What do AC Generators consist of?

Answer 14

• Loop of wire
• Stationary Magnetic Field
• Prime Mover
• Permanent Magnet

Question 15

What is the displacement between 3 phases of electricity?

Answer 15

120 Degrees

Question 16

How many interconnected power systems cover parts of both the US and Canada?

Answer 16

4

Question 17

Which part of the electric system is also referred to as “The Bulk Power System?”

Answer 17

Transmission

Question 18

Which Substation operates at Distribution-level voltages?

Answer 18

“B” Bank

Question 19

What is an example of a “B” Bank Substation?

Answer 19

66kV / 12kV

Question 20

Typically, dry-cooled transformers will not be used above _____ kVA.

Answer 20

50kVA

Question 21

What type of cooling do SCE Distribution Transformers use?

Answer 21

oil or liquid immersed

Question 22

What function to potential transformers provide the Edison system?

Answer 22

Provide a proportionate value of voltage for metering

Question 23

What voltage would you get phase-to-phase when you wire three windings in WYE configuration?

Answer 23

The single winding times 1.73

Question 24

A 75kVA three-phase, wye-connected transformer has phase-to-neutral voltage of 120V. What is the line voltage?

Answer 24

240V

Question 25

How do you know if a transformer is additive or subtractive?

Answer 25

Read the Transformer Nameplate

Question 26

What is harmonic in an electrical system?

Answer 26

A multiple of the fundamental frequency of 60 Hz

Question 27

What is an advantage of delta transformer connections?

Answer 27

They trap third harmonics

Question 28

Vectors are useful in expressing electrical systems because they indicate both _____ and ____ of a force or quality

Answer 28

Magnitude and Angle

Question 29

What is the standard SCE phase sequence?

Answer 29

BAC, CBA

Question 30

How would current flow in the primary coil and secondary coil of a single phase transformer?

Answer 30

In H1 and out X1

Question 31

What are guy strain insulators used for?

Answer 31

To break and insulate a guy wire from the ground.

Question 32

What size guy wire does transmission use for span guys?

Answer 32

9/32"

Question 33

When would you use an anchor rod extension?

Answer 33

When raised grade changes are expected.

Question 34

What best describes the function and proper use of guy strain rods?

Answer 34

On tangent poles in wind-prone areas

Question 35

What is the preferred type of anchor to use in T & D construction?

Answer 35

Power-Installed Screw Anchor

Question 36

When would you use a plate anchor?

Answer 36

In extremely loose soil, inaccessible areas, and in rock or hard soil where a granite anchor cannot be satisfactorily installed.

Question 37

The hole for a plate anchor can be dug using___

Answer 37

A Shovel or other handtools or a backhoe

Question 38

What are overhead splices used at SCE?

Answer 38

- Compression Line Splices | - Jumper Loop Splices

Question 39

How far apart must line splices be in the same span?

Answer 39

At least 100'

Question 40

Tools and materials used for overhead Transmission conductor splices include:

Answer 40

Hydraulic pump, press head, and hoses and compression dies

Question 41

What are the key steps of installing a repair splice?

Answer 41

Center the repair sleeve on the center of the damaged section of the conductor. Mark the center of the sleeve and tape the conductor strands together securely at each end of the sleeve. Make the outer layer of strands as tight as possible.

Question 42

Under arm PVC is used to

Answer 42

Protect wires

Question 43

Which of the following transformers are used in the SCE electrical system?

Answer 43

Current; Potential