What is the main purpose of power transmission lines?
A Convert mechanical energy to electrical energy
B Deliver electricity from generation stations to distribution networks
C Step up the voltage for household use
D Provide backup power during faults
Power transmission lines transport electricity from power generation stations to substations or distribution networks over long distances at high voltages to minimize losses.
What is the unit of electrical power?
A Volt
B Watt
C Ohm
D Ampere
Electrical power is measured in watts (W). It represents the rate of energy transfer or consumption in an electrical circuit.
What is the purpose of switchgear in a power system?
A Transmit power over long distances
B Protect electrical equipment from damage during faults
C Reduce voltage for household usage
D Measure power factor
Switchgear includes devices such as circuit breakers, isolators, and relays that protect the power system by isolating faulty sections and ensuring system safety.
What type of transformer is used to reduce the voltage in a distribution network?
A Step-up transformer
B Step-down transformer
C Isolation transformer
D Auto-transformer
Step-down transformers are used in distribution networks to reduce high transmission voltages to levels suitable for residential and commercial use.
What is the main advantage of underground power cables over overhead transmission lines?
A Higher voltage capacity
B Lower installation costs
C Protection from weather-related damage
D Reduced maintenance requirements
Underground cables are protected from weather conditions such as storms and lightning, making them more reliable than overhead lines.
What is “load shedding”?
A Disconnecting non-essential loads during supply shortages
B Increasing the frequency of the power system
C Reducing transmission losses
D Improving grid efficiency
Load shedding temporarily disconnects certain loads to balance supply and demand, preventing overloading and system collapse during power shortages.
What is the role of a power distribution network?
A Generate electricity from renewable sources
B Deliver electricity to end consumers
C Transmit power over long distances
D Store electrical energy for peak demand
The power distribution network delivers electricity from substations to end users, such as households, businesses, and industries, at usable voltage levels.
What is the primary purpose of a load flow study?
A Determine the cost of electricity generation
B Analyze the steady-state performance of the power system
C Protect the system from faults
D Manage blackout recovery
Load flow studies determine voltage, current, power flow, and losses in the system under normal operating conditions to ensure efficient operation and planning.
What does “power system stability” refer to?
A The system’s ability to operate under heavy faults
B The system’s capability to maintain equilibrium during disturbances
C The reduction of transmission losses
D The increase of system frequency
Power system stability ensures that the system can return to normal operation after disturbances such as faults or load changes, maintaining reliable power delivery.
What type of protection system uses relays and circuit breakers?
A Mechanical protection
B Electrical protection
C Hydraulic protection
D Thermal protection
Relays and circuit breakers are key components of electrical protection systems, detecting and isolating faults to prevent damage to the power system.
Which type of fault is the most severe in a power system?
A Line-to-ground fault
B Double line-to-ground fault
C Line-to-line fault
D Three-phase fault
A three-phase fault is the most severe type of fault as it causes maximum current to flow, leading to potential damage to equipment and disruption in the system.
What is “economic load dispatch”?
A Balancing the load across transmission lines
B Optimizing generator output to minimize cost
C Reducing reactive power
D Controlling load shedding
Economic load dispatch involves allocating generation among units in a way that minimizes total operating costs while meeting system demand and constraints.
What is the function of a surge protector?
A Step up voltage
B Protect equipment from voltage spikes
C Maintain frequency stability
D Reduce power losses
Surge protectors shield electrical equipment from sudden voltage spikes caused by lightning or switching operations, preventing damage.
What does “frequency control” ensure in a power system?
A Voltage remains constant
B Current remains constant
C Power supply is synchronized with demand
D Load is evenly distributed
Frequency control ensures that power generation matches load demand to maintain the system’s frequency at a stable value, such as 50 Hz or 60 Hz.
What is the purpose of a current transformer (CT)?
A Step up voltage
B Step down current for measurement
C Isolate faults in the system
D Generate electricity
A current transformer (CT) reduces high current levels in the power system to manageable levels for measurement and protection devices.
What is meant by “fault analysis” in power systems?
A Identifying locations of power generation
B Analyzing abnormal conditions in the system
C Reducing voltage drop in transmission lines
D Increasing system efficiency
Fault analysis involves studying the effects of faults (e.g., short circuits) on a power system to design protection schemes and ensure system reliability.
What is the advantage of renewable energy integration into the grid?
A Reduces dependency on fossil fuels
B Increases the need for load shedding
C Reduces grid stability
D Decreases the systemโs efficiency
Integrating renewable energy sources, such as solar and wind, reduces reliance on fossil fuels, decreasing greenhouse gas emissions and promoting sustainability.
What is “power quality” in a power system?
A Efficiency of the generation units
B Reliability of power delivery to consumers
C Consistency of voltage, frequency, and waveform
D Reduction of power losses in transmission
Power quality refers to delivering electricity with stable voltage, frequency, and waveform, ensuring the efficient operation of electrical devices.
Which device is used to measure electrical power in a circuit?
A Ammeter
B Voltmeter
C Wattmeter
D Ohmmeter
A wattmeter is used to measure electrical power in a circuit, providing readings of active power consumption in watts.
What is the purpose of energy management systems (EMS) in power systems?
A Store excess energy during peak hours
B Optimize energy usage and reduce costs
C Reduce the frequency of power outages
D Generate renewable energy
EMS helps monitor, control, and optimize energy usage in power systems, ensuring efficient operation and cost reduction while maintaining system reliability.