WorksheetsElectrical distribution
Total questions: 29
Worksheet time: 16mins
What do fuel cells, batteries, and solar cells have in common?
a. They all produce static electricity
b. They are all sources of direct current
c. They are all sources of alternating current
d. They can all be used to power automobiles
What can you infer about this source of electricity?
a. It is a source of alternating current
b. It is a source of direct current
c. It is a source of static electricity
d. It is a source of electromagnetic radiation
How does alternating current differ from direct current?
a. Alternating current produces more voltage than direct current
b. Alternating current always flows in the same direction; the direction of a direct current switches back and forth
c. Direct current produces more voltage than alternating current
d. Direct current always flows in the same direction; the direction of an alternating current switches back and forth
How does electricity travel from power plants to your house?
a. It travels through the air as electromagnetic waves
b. Through a series of generators
c. Through a series of many transformers
d. Through transmission wires
What is the function of every generator on Earth?
a. Changing wind energy into electrical energy
b. Changing heat energy into electrical energy
c. Changing mechanical energy into electrical energy
d. Changing solar energy into electrical energy
How does a generator create current?
a. By using an electromagnet
b. By using an internal combustion engine
c. By using a fan
d. By using energy from the sun
Place the following events in sequence: A) Voltage is increased by a transformer; B) Voltage is decreased by a transformer; C) Electrical current enters your home
a. A, B, C
b. B, A, C
c. A, C, B
d. B, C, A
Which of the following are sources of mechanical energy?
a. Cars and trucks
b. Radios and televisions
c. Transmission lines and transformers
d. Wind and fossil fuels
What is the main function of a turbine?
a. Producing a magnetic field
b. Spinning
c. Reducing the voltage of an electrical current
d. Increasing the voltage of an electrical current
What is one possible reason why it's a good idea to conserve electricity?
a. It is often produced by burning fossil fuels, which are a polluting, non-renewable resource.
b. Power companies only give each home a limited amount of electricity every day.
c. Using too much electricity can start dangerous electrical fires.
d. Using too much electricity can cause power plants to break down.
Which of the following devices raises voltage so that it can travel to long distances?
POWER PLANT
STEP-UP TRANSFORMER
STEP-DOWN TRANSFORMER
What energy transformation takes place in a generator?
Electrical to mechanical energy
Mechanical to electrical energy
heat energy
What do you call a facility of producing electricity from energy sources?
Power plant
transformer
generator
Cathy turned on a lamp switch on her room. Which of the following is the correct path of electrical power that can be traced back to the source?
power plant ⇒transmission substations ⇒distribution ⇒substations ⇒ residences A
power plants ⇒distribution substation ⇒transmission substations⇒residences
power plants ⇒distribution substations ⇒national grid ⇒ residences
Give the correct order of transmission and distribution of electrical energy to consumers. 1 Distribution Substation 2 Power Plant 3 Transmission Station 4 Consumers
1234
2314
4132
Power plant generates electricity.
True
False
Step-up transformers reduce the output voltage.
True
False
Distribution substation uses big transformer to step up voltage.
True
False
Transmission lines transport high-voltage electricity over long distances.
True
False
Distribution lines carries electricity at lower voltage.
True
False
Why is alternating current (AC) used instead of direct current (DC) in electrical supply systems?
AC can be easily transformed from one voltage to another
AC produces less arcing and sparking on contacts
Transmission losses are lower with low current
All of the above
What is the purpose of using transformers in the transmission and distribution system?
To step-up and step-down voltages
To reduce switchgear and fuse gear ratings
To balance the load on the supply system
To reduce cable sizes
Which cooling method is generally used for small transformers up to 3MVA?
Air cooled
Oil cooled
Gas cooled (Sf6)
None of the above
What is the purpose of balancing the load across the phases in a three-phase supply?
To prevent any one phase from being overloaded
To reduce transmission losses
To increase the voltage drop in the cables
To improve power factor
What voltage is typically used for local distribution in England and Wales?
11kV
33kV
132kV
400kV
Which cooling method is generally used for transformers up to about 30MVA?
Air cooled
Oil cooled
Gas cooled (Sf6)
None of the above
What is the purpose of using a three-phase and neutral supply for industrial installations?
To provide a choice of two voltages
To reduce switchgear and fuse gear ratings
To balance the load on the supply system
To reduce cable sizes
What is the maximum current rating (In) fitted in the Distribution Network Operator (DNO) service cut-out for a domestic premise?
50 amperes
100 amperes
200 amperes
400 amperes
What are the separate electrical items commonly found in a sub-station?
Transformers, isolators, fuses/circuit breakers, switchgear
Generators, transformers, cables, meters
Motors, capacitors, resistors, relays
Batteries, inverters, solar panels, wind turbines
