Power Distribution Systems: A Comprehensive Guide for Electrical Technology Students

Question 1

Which of the following is a key difference between distribution systems and transmission systems in power distribution?

Accepted Answer

Transmission systems operate at higher voltage levels than distribution systems.

Answer

Distribution systems operate at higher voltage levels than transmission systems.

Answer

Distribution systems use only overhead power lines, while transmission systems use only underground cables.

Question 2

Which type of transformer is used to decrease the voltage from the transmission line to a suitable level for distribution?

Accepted Answer

Distribution transformer

Answer

Substation transformer

Answer

Autotransformer

Answer

Power transformer

Question 3

In overhead power distribution lines, which type of conductor is commonly employed?

Accepted Answer

Bare wire

Answer

Twisted pair

Answer

Insulated wire

Answer

Fiber optic cable

Question 4

What is the main objective of a voltage regulator in a power distribution system?

Accepted Answer

Maintaining a constant voltage level at the customer's location

Answer

Isolating faults

Answer

Preventing overloads

Question 5

When sizing a distribution transformer, which factor plays a pivotal role?

Accepted Answer

Load demand

Answer

Voltage level

Answer

Line distance

Question 6

In a power distribution system, what is the primary purpose of a neutral wire?

Accepted Answer

Providing a return path for unbalanced currents

Answer

Protecting against electrical shocks

Answer

Carrying additional power

Answer

Enhancing voltage regulation

Question 7

In a power distribution system, when an energized conductor comes into contact with the ground, which type of fault occurs?

Accepted Answer

Ground fault

Answer

Open circuit

Answer

Overload

Answer

Short circuit

Question 8

Protective relays in a power distribution system are primarily responsible for:

Accepted Answer

Detecting and isolating faults promptly

Answer

Improving efficiency

Answer

Measuring power consumption

Answer

Regulating voltage

Question 9

Which distribution system topology utilizes interconnected substations to allow for multiple paths of power flow?

Accepted Answer

Network topology

Answer

Radial topology

Answer

Loop topology

Answer

Bus topology

Question 10

What type of transformer is specifically designed to reduce voltage levels for distribution purposes?

Accepted Answer

Distribution transformer

Answer

Power transformer

Answer

Autotransformer

Answer

Instrument transformer

Question 11

In a power distribution system, what is the primary function of a substation?

Accepted Answer

To switch, regulate, and safeguard the flow of electricity

Answer

To generate electricity through various means

Answer

To store electrical energy for later use

Question 12

Which of the following voltage levels is typically used for primary distribution lines?

Accepted Answer

13.8 kV

Answer

480 V

Answer

120 V

Answer

220 V

Question 13

What is the main purpose of employing a radial distribution system?

Accepted Answer

Distributing power to numerous loads via a single path

Answer

Providing backup power in the event of an outage

Answer

Interconnecting various substations

Question 14

What is the primary purpose of utilizing voltage regulators in power distribution systems?

Accepted Answer

Maintaining a constant voltage level at customer connection points

Answer

Protecting transformers from damage

Answer

Isolating electrical faults

Question 15

In power distribution systems, which of the following is a common type of protective device?

Accepted Answer

Circuit breaker

Answer

Ammeter

Answer

Wattmeter

Answer

Voltmeter

Question 16

What is the primary purpose of grounding in a power distribution system?

Accepted Answer

Providing a safe path for fault current to flow

Answer

Increasing voltage levels for distribution

Answer

Protecting against lightning strikes

Answer

Reducing power losses in the system

Question 17

When distributing power underground, which type of cable is commonly employed?

Accepted Answer

Direct buried cable

Answer

Tray cable

Answer

Aerial cable

Answer

Conduit cable

Question 18

What is the paramount objective of maintaining a power distribution system?

Accepted Answer

Ensuring reliable and safe operation of the system

Answer

Reducing operational costs at any expense

Answer

Increasing power output beyond design limits

Answer

Meeting environmental regulations and standards

Question 19

What is the main purpose of a substation in a power distribution system?

Accepted Answer

To reduce voltage and distribute power to local consumers

Answer

To generate electricity from renewable sources

Answer

To store excess energy for peak demand

Question 20

Which type of distribution line is commonly used for transmitting power over long distances?

Accepted Answer

Overhead high-voltage transmission line

Answer

Underground low-voltage distribution line

Answer

Submersible cable line

Answer

Aerial bundled conductor line

Question 21

What is the primary function of a voltage regulator in a power distribution system?

Accepted Answer

To ensure a consistent voltage level at the customer's service entrance

Answer

To isolate faults on the distribution line

Answer

To protect equipment from overvoltages

Question 22

What is the standard voltage level for residential distribution systems?

Accepted Answer

120/240 V

Answer

13.8 kV

Answer

277/480 V

Answer

4 kV

Question 23

What is the primary purpose of a distribution transformer substation?

Accepted Answer

To reduce voltage for local power distribution

Answer

To transmit electricity over long distances

Answer

To store electricity for later use

Answer

To generate electricity

Question 24

What is the role of a lightning arrester in a power distribution system?

Accepted Answer

To safeguard equipment from lightning strikes

Answer

To regulate voltage levels

Answer

To isolate faults on distribution lines

Answer

To measure power consumption

Question 25

Which of the following transformers is designed to transmit electrical power over extensive distances in a power distribution system?

Accepted Answer

Power transformer

Answer

Distribution transformer

Answer

Instrument transformer

Answer

Isolation transformer

Question 26

What is the primary role of a protective relay in a power distribution network?

Accepted Answer

To detect and isolate electrical faults

Answer

To monitor power consumption

Answer

To regulate voltage levels

Answer

To synchronize generators

Question 27

What is the main function of a substation within a power distribution system?

Accepted Answer

To receive, transform, and distribute electrical power

Answer

To generate electricity

Answer

To control power flow

Answer

To isolate faults

Question 28

Which factor is the most significant in determining the physical size of a power transformer?

Accepted Answer

Power rating

Answer

Frequency

Answer

Efficiency

Answer

Voltage ratio

Question 29

What is the core purpose of a distribution automation system?

Accepted Answer

To monitor, control, and optimize the distribution network

Answer

To improve power quality

Answer

To detect and isolate faults

Question 30

Which electrical parameter has the most significant impact on power loss in distribution lines?

Accepted Answer

Resistance

Answer

Inductance

Answer

Frequency

Answer

Capacitance

Question 31

What is the primary objective of grounding in a power distribution system?

Accepted Answer

To provide a low-impedance path for fault currents

Answer

To isolate electrical faults

Answer

To protect against voltage surges

Answer

To improve power factor

Question 32

What is the primary function of a distribution transformer in a power distribution system?

Accepted Answer

To reduce voltage from high transmission levels to lower distribution levels

Answer

To generate electricity for distribution lines.

Answer

To protect distribution lines from overcurrents.

Question 33

Which type of line is commonly used for overhead power distribution?

Accepted Answer

Bare overhead conductors

Answer

Twisted pair cables

Answer

Coaxial cables

Question 34

What is the primary function of a substation in a power distribution system?

Accepted Answer

To regulate voltage levels, control circuit switching, and protect the system from faults.

Answer

To store electrical energy.

Answer

To generate electrical power.

Question 35

Which factor primarily contributes to power loss in distribution lines?

Accepted Answer

The resistance of the line conductors.

Answer

The capacitance of the line.

Answer

The frequency of the electrical current.

Answer

The inductance of the line.

Question 36

What is the main function of a voltage regulator in a power distribution system?

Accepted Answer

To maintain a stable and consistent voltage at consumer locations.

Answer

To protect lines from overvoltage events.

Answer

To isolate faults within the system.

Question 37

What is the primary purpose of protection devices in a power distribution system?

Accepted Answer

To safeguard equipment and personnel from electrical hazards and faults.

Answer

To enhance the quality of power delivered to consumers.

Answer

To increase the overall efficiency of the system.

Question 38

Which of the following is a common component of a distribution automation system?

Accepted Answer

Remote terminal unit (RTU)

Answer

Transformer

Answer

Diesel generator

Answer

Battery

Question 39

What is the primary function of a distribution transformer in a power distribution system?

Accepted Answer

To step down the voltage from high voltage transmission lines to a lower voltage suitable for local use.

Answer

To increase the voltage for long-distance transmission.

Question 40

Which type of conductor is commonly used for overhead power lines?

Accepted Answer

Aluminum conductor steel reinforced (ACSR)

Answer

Fiber optic cable

Answer

Coaxial cable

Answer

Copper wire

Question 41

What is the main purpose of a substation in a power distribution system?

Accepted Answer

To control and regulate the flow of electricity, and to transform voltage levels.

Answer

To generate electricity.

Answer

To store excess electricity for later use.

Question 42

A three-phase power system uses how many conductors for power distribution?

Accepted Answer

Four

Answer

Three

Answer

Two

Answer

Five

Question 43

What is the primary function of a circuit breaker in a power distribution system?

Accepted Answer

To interrupt the flow of electricity in case of a fault or overload.

Answer

To regulate the voltage of the power supply.

Answer

To measure the amount of electricity consumed.

Question 44

Which of the following is NOT a common type of power distribution system?

Accepted Answer

Direct Current (DC) distribution

Answer

Network distribution

Answer

Radial distribution

Answer

Ring distribution

Question 45

What is the primary concern regarding voltage sags in a power distribution system?

Accepted Answer

They can cause equipment malfunction or damage.

Answer

They reduce the cost of electricity distribution.

Answer

They are a normal part of the power distribution process.

Answer

They increase the efficiency of power transmission.

Question 46

What is the main advantage of using underground power lines compared to overhead lines?

Accepted Answer

They are less susceptible to weather damage.

Answer

They require less maintenance.

Answer

They have lower energy losses.

Answer

They are more cost-effective to install.

Question 47

A power distribution system is designed to ensure a reliable and safe supply of electricity to consumers. Which of the following factors is NOT a key consideration in the design of a power distribution system?

Accepted Answer

The number of employees working in the system.

Answer

The availability of suitable infrastructure.

Answer

The load demand of the area being served.

Question 48

What is the primary function of a protective relay in a power distribution system?

Accepted Answer

To detect faults and initiate the tripping of circuit breakers.

Answer

To measure the amount of electricity consumed.

Answer

To regulate the voltage of the power supply.

Question 49

Which type of transformer is used to step down voltage from the transmission level to the distribution level?

Accepted Answer

Distribution transformer

Answer

Power transformer

Answer

Autotransformer

Question 50

What is the primary purpose of a substation in a power distribution system?

Accepted Answer

To switch and protect electrical circuits

Answer

To step up voltage

Answer

To convert AC to DC

Answer

To generate electricity

Question 51

Which type of conductor is commonly used for overhead power lines?

Accepted Answer

Aluminum Conductor Steel Reinforced (ACSR)

Answer

Copper

Answer

Silver

Answer

Polyethylene

Question 52

What is the recommended minimum ground clearance for a 12.47 kV power line?

Accepted Answer

10 feet

Answer

15 feet

Answer

5 feet

Answer

20 feet

Question 53

Which type of circuit protection device is used to protect transformers from overcurrent?

Accepted Answer

Fuse

Answer

Relay

Answer

Circuit breaker

Answer

Surge arrester

Question 54

What is the main advantage of using underground power lines over overhead lines?

Accepted Answer

Improved reliability and reduced visual impact

Answer

Lower cost

Answer

Easier maintenance

Answer

Higher voltage capacity

Question 55

Which of the following is a factor that affects the power loss in a distribution line?

Accepted Answer

Conductor resistance

Answer

Current

Answer

Voltage

Answer

Circuit length

Question 56

What is the purpose of a voltage regulator in a power distribution system?

Accepted Answer

To maintain a constant voltage level at the customer's premises

Answer

To protect against overvoltage

Answer

To isolate faulty sections

Question 57

Which type of load is characterized by a high starting current that is many times the running current?

Accepted Answer

Motor load

Answer

Capacitive load

Answer

Lighting load

Answer

Resistive load

Question 58

What is the recommended method for installing underground power lines?

Accepted Answer

Direct burial or trenching

Answer

Submarine installation

Answer

Overhead installation

Answer

Aerial installation