Electrical Grid: Chapters 5 & 6 (Possible Test Questions) - WEEK 4

Question 1

1) Name the different types of generation

Answer 1

• Steam
• Hydroelectric
• Wind
• Distribution
• Combustion Engine / Turbine

Question 2

2) Steam is a common method of producing electrical energy. High pressure steam is produced by any of these methods:

Answer 2

• Fossil-fired generation
• Nuclear-fired generation
• Geothermal generation
• Solar generation

Question 3

3) List a few different sources of fossil fuel.

Answer 3

• Coal

- Petroleum
- Natural gas

Question 4

4)What is the term, “combined cycle generation”?

Answer 4

• Gas is harvested and is fired in a natural gas combustion turbine, which spins a generator. In many cases, the hot exhaust from the natural gas turbine is used to produce steam, which can spin an additional steam turbine connected to another generator. This process is called “combined cycle”

Question 5

5) Crude oil generation involves the heating of what?

Answer 5

• Oil in a boiler, which also boils water into a high-pressured steam.

Question 6

6) What percent of the electrical energy produced in the US today derives from nuclear generation facilities.

Answer 6

• 20%

Question 7

7) In Nuclear Generation, heat from the ____________ produces the steam needed to turn a generator.

Answer 7

• reactor core

Question 8

8) Geothermal Generation involves the natural heat from what?

Answer 8

• Geysers or hot springs to produce steam.

Question 9

9) In a Geothermal Generator, steam is produced from the heat energy provided by the _____ to turn a generator.

Answer 9

• Earth

Question 10

10) What are the two methods of generating electricity using Solar Power?

Answer 10

• Photovoltaic

- Parabolic Trough

Question 11

11) Define: Photovoltaic

Answer 11

• Photovoltaic uses semi-conducting solar panels to produce electrical power in the form of direct current. The direct current can then be converted into alternating current to allow it to feed into the electrical system.

Question 12

12) Define: Parabolic Trough

Answer 12

• Parabolic Trough harnesses the heat energy from the sun to heat up salt to a molten state, and then the molten salt passes through through a boiler where high-pressure steam is produced. That steam is then used to turn a turbine connected to a generator.

Question 13

13) Other means of producing electrical energy from steam pressure include?

Answer 13

• Biomass and Resource Recovery generation stations.

Question 14

14) Biomass uses biological materials such as:

Answer 14

• wood chips
• sugar canes
• switch grass

Question 15

15) In Hydroelectric Generation, what are the two methods of obtaining mechanical motion using water pressure to generate electrical electricity.

Answer 15

• Falling water from a natural waterfall

- Hydroelectric Dam: water is backed up into a reservoir

Question 16

16) Wind Generation is know to be:

Answer 16

• One of the fastest methods of producing electricity in the world.

Question 17

17) Distributed Generation, sometimes referred to as what?

Answer 17

• Distributed Energy Resource

- Dispersed Microgeneration

Question 18

18) True or False: Smaller scale generators are popular for back-up power in facilities where power is consumed around the clock, such as hospitals.

Answer 18

• True

Question 19

19) True or False: Energy can be converted, but cannot be created or destroyed.

Answer 19

-True

Question 20

20) The law of charges also states that opposite charges _______.

Answer 20

• attract

Question 21

21) In AC circuits, the terms “positive and negative” refer to:

Answer 21

• the direction of current flow in a conductor.

Question 22

22) The strength of the voltage to be produced depends on three factors. These factors are what?

Answer 22

• The number of turns in the coil of wire
• The strength of the magnetic field
• The speed at which the magnet lines of flux pass through the coil

Question 23

23) Please best describe a sine wave.

Answer 23

• A sine wave is a graphical representation of what is happening to voltage in an AC circuit over a period of time.

Question 24

24) After a generator has rotated 90 degrees (1/4 of a turn), the voltage has reached:

Answer 24

• maximum or peak positive value

Question 25

25) After a generator has rotated 180 degrees (1/2 of a turn), the voltage has:

Answer 25

• decreased to zero

Question 26

26) At 270 degrees (3/4 of a turn) where would the voltage be?

Answer 26

• Maximum or peak negative value

Question 27

27) After one 360 degree rotation or a full rotation, this is also referred to as a what?

Answer 27

• A cycle

Question 28

28) In one cycle, how many times does a generator produce 0 (zero) volts

Answer 28

• 3 times

Question 29

29) A sine wave has a peak voltage of 7200 volts. What is the voltage after 210 degrees of rotation?

Answer 29

E(inst) = E(max) x Sine
E(inst) = 7200 x Sine 210˚
E(inst) = -3600 volts

Question 30

30) Because DC is __________________, it will produce a ________________________.

Answer 30

• constant in nature

- constant amount of power

Question 31

31) The RMS value is always _____ than the peak or maximum value.

Answer 31

• lower

Question 32

32) What formula is used to find the RMS value of the voltage?

Answer 32

• RMS = 0.707 x Peak

Question 33

33) A sine wave has a maximum voltage of 10184 volts. What is the RMS value of the voltage?

Answer 33

RMS = 0.707 x Peak
RMS = 0.707 x 10184
RMS = 7200 volts

Question 34

34) If RMS is already known, how would you find the peak value?

Answer 34

• 0.707 x 2 = 1.414
• 1.414 = a constant value
• Peak = 1.414 x RMS

Question 35

35) List 3 different types of Alternating Current Circuits

Answer 35

• Resistive (electrical heating equipment, incandescent lighting)
• Inductive (Induction motors, transformers)
• Capacitive (Synchronous motors, capacitors)

Question 36

36) True power exists in an AC circuit when the load is _________________.

Answer 36

• Purely resistive