B A technology for remote monitoring and control of energy usage
C A type of energy storage system
D A transformer control mechanism
AMI integrates smart meters with communication networks to provide real-time data on energy usage, improve grid management, and support efficient billing and energy distribution.
What is the role of a microgrid?
A To generate power only from fossil fuels
B To operate independently or in connection with the main grid
C To transmit power over long distances
D To step down voltage
Microgrids are localized systems that can operate either autonomously or connected to the main grid, integrating renewable sources and offering enhanced reliability and flexibility.
How does increasing line capacitance affect transmission lines?
A Reduces power losses
B Causes a rise in receiving-end voltage
C Increases line impedance
D Decreases line inductance
Increasing line capacitance stores more charge and causes a rise in the voltage at the receiving end of the line, especially under light-load conditions (Ferranti Effect).
What is the function of a lightning arrester in a transmission system?
A To reduce line impedance
B To protect the system from overvoltage due to lightning
C To step up voltage levels
D To store energy
Lightning arresters divert high-voltage surges from lightning strikes to the ground, preventing damage to electrical equipment and maintaining system safety.
Which protection device is used to limit the fault current in a power system?
A Capacitor
B Current limiting reactor
C Circuit breaker
D Relay
Current limiting reactors introduce inductive reactance into the system, limiting the fault current to a safe level and protecting equipment.
What is the primary advantage of integrating renewable energy sources into microgrids?
A To reduce load balancing
B To enable sustainable and reliable local power supply
C To increase transmission line losses
D To regulate system frequency
Renewable energy sources like solar and wind provide sustainable, local power, improving reliability and reducing dependence on the main grid.
What is the primary factor influencing the sag in transmission lines?
A Line capacitance
B Conductor weight and tension
C Line resistance
D Power factor
The sag in transmission lines is affected by the conductor’s weight and the tension applied. Proper sag ensures mechanical stability and avoids excessive tension.
What is the primary cause of fault currents in a power system?
A Excessive capacitance
B Short circuits or insulation failures
C High power factor
D Voltage fluctuations
Fault currents typically arise from short circuits, insulation failures, or other unexpected conditions that cause large, harmful current flows through the system.
What is the primary function of a lightning arrester in a transmission system?
A To reduce line impedance
B To protect the system from overvoltage due to lightning
C To step up voltage levels
D To store energy
Lightning arresters prevent overvoltage in the system by directing the electrical surges caused by lightning safely to the ground, protecting the equipment from damage.
What is the role of reactive power in voltage stability?
A To increase active power
B To maintain voltage levels within acceptable limits
C To reduce line resistance
D To improve power factor
Reactive power helps maintain voltage levels in the system, ensuring the proper operation of equipment and avoiding voltage instability.
What is the primary purpose of line impedance in a transmission line?
A To regulate voltage
B To resist the flow of current and control power transfer
C To step up voltage
D To reduce capacitance
Line impedance, comprising resistance and reactance, governs how current flows through the line, affecting power transfer and voltage regulation.
What is the effect of inductance in a transmission line?
A Increases line resistance
B Opposes changes in current
C Reduces voltage drop
D Improves power factor
Inductance opposes rapid changes in current due to the magnetic field created around the conductor, affecting system stability.
How does capacitance affect a transmission line?
A Increases power losses
B Causes voltage rise at light loads
C Reduces conductor resistance
D Eliminates inductance
Capacitance causes the Ferranti effect, where the receiving-end voltage becomes higher than the sending-end voltage under low load conditions.
What is corona discharge?
A A fault in the conductor
B The ionization of air around high-voltage conductors
C A type of short circuit
D An insulation failure
Corona discharge occurs when the electric field strength around a conductor exceeds the breakdown strength of air, causing energy loss and ionization of air.
Which factor increases corona loss?
A Decreasing voltage
B Increasing conductor size
C Decreasing atmospheric pressure
D Increasing conductor spacing
Lower atmospheric pressure reduces the breakdown strength of air, increasing the likelihood of corona discharge.
What is the primary purpose of sag in a transmission line?
A To improve power quality
B To allow for thermal expansion and contraction of the conductor
C To reduce inductive reactance
D To stabilize capacitance
Sag allows conductors to expand and contract with temperature changes, ensuring mechanical stability and preventing excessive tension.
What is the impact of excessive sag in a transmission line?
A Increases line resistance
B Decreases ground clearance
C Reduces capacitance
D Increases voltage
Excessive sag reduces the clearance between the conductor and the ground, increasing the risk of accidents and reducing safety.
What is earthing’s primary role in a power system?
A To increase capacitance
B To provide a safe path for fault currents to the ground
C To reduce inductance
D To stabilize frequency
Earthing ensures safety by directing fault currents into the ground, preventing hazardous voltages from causing damage to equipment and personnel.
What is the purpose of fault current analysis in power systems?
A To measure voltage stability
B To determine the magnitude and location of faults
C To reduce conductor resistance
D To increase capacitance
Fault current analysis identifies the magnitude and location of faults, which helps in designing protection systems to isolate faults and protect equipment.
Which protection device detects faults and triggers a circuit breaker?
A Capacitor
B Relay
C Lightning arrester
D Transformer
Relays monitor the power system for faults and abnormal conditions, signaling circuit breakers to disconnect faulty sections and prevent damage.
What is grid integration in power systems?
A Combining multiple loads in a grid
B Connecting renewable energy sources to the power grid
C Isolating renewable energy sources from the grid
D Increasing voltage levels
Grid integration involves connecting renewable energy sources like solar and wind to the main power grid, ensuring reliable energy distribution.
What is the role of a smart meter in a distribution system?
A To step up voltage levels
B To measure energy usage and provide real-time data
C To reduce power losses
D To improve line capacitance
Smart meters provide real-time data on energy consumption, allowing for accurate billing, demand-side management, and improved energy efficiency.
What is Advanced Metering Infrastructure (AMI)?
A A system for manual meter reading
B A technology for remote monitoring and control of energy usage
C A type of energy storage system
D A transformer control mechanism
AMI integrates smart meters and communication systems, enabling remote monitoring, energy management, and efficient billing processes.
What is a microgrid?
A A power grid for long-distance transmission
B A localized energy system that can operate independently or with the main grid
C A control system for transformers
D A device for voltage regulation
Microgrids are small-scale power systems that can function independently or be connected to the larger grid, providing localized energy solutions.
What is the primary cause of reactive power in a power system?
A Inductive and capacitive loads
B Inductive and capacitive loads
C Resistance of conductors
D Low system voltage
Reactive power is required by inductive and capacitive loads to create and sustain electric and magnetic fields, helping in the operation of motors, transformers, etc.
How does capacitance affect high-voltage, long-distance transmission lines?
A Increases line resistance
B Leads to Ferranti effect under light loads
C Reduces power losses
D Eliminates voltage fluctuations
Capacitance in long-distance transmission lines causes a voltage rise at the receiving end under light load conditions, known as the Ferranti effect.
What is the primary purpose of a lightning arrester?
A To reduce line impedance
B To protect the system from overvoltage due to lightning
C To step down voltage levels
D To store energy
Lightning arresters are used to protect the power system from lightning-induced surges by directing the high-voltage surge safely to the ground.
What is the main advantage of microgrids?
A They reduce power factor
B They improve energy reliability and integrate renewables
C They increase line losses
D They eliminate voltage fluctuations
Microgrids enhance the reliability of local power supplies and allow for efficient integration of renewable energy sources, such as solar and wind.
What is the primary cause of reactive power in a power system?
A Inductive and capacitive loads
B Inductive and capacitive loads
C Resistance of conductors
D Low system voltage
Reactive power is required by inductive and capacitive loads, like motors and transformers, to create and sustain electric and magnetic fields.
What is the purpose of reactive power compensation in a transmission system?
A To increase active power
B To stabilize voltage levels and improve power factor
C To reduce system losses
D To increase system frequency
Reactive power compensation ensures that voltage levels are maintained within acceptable limits and improves the overall power factor, making the system more efficient.
What is the main purpose of a transmission line in a power system?
A To generate power
B To distribute power locally
C To carry high-voltage power over long distances
D To store electrical energy
Transmission lines transport high-voltage power from generating stations to substations efficiently over long distances, minimizing energy losses.
What type of cable is most commonly used for underground power transmission?
A Coaxial cable
B XLPE cable
C Twisted pair cable
D Fiber optic cable
XLPE (Cross-Linked Polyethylene) cables are widely used for underground power transmission due to their excellent thermal and electrical insulation properties.
Which voltage range is typically considered as medium voltage?
A 0–1 kV
B 1–33 kV
C 33–110 kV
D Above 110 kV
Medium voltage systems operate between 1 kV and 33 kV and are used for regional distribution in industrial and commercial settings.
What is the purpose of an overhead ground wire in a transmission line?
A To transmit power
B To protect against lightning strikes
C To reduce line impedance
D To balance reactive power
Overhead ground wires are installed to shield conductors from lightning by safely directing lightning surges to the ground.
Which factor primarily affects the choice of conductor material in transmission lines?
A Weight and flexibility
B Conductivity and cost
C Appearance and texture
D Melting point
Materials like aluminum and copper are chosen for their high conductivity and cost-effectiveness, making them suitable for power transmission.
What is the role of an insulator in a transmission line?
A To carry electrical current
B To prevent current leakage to the supporting structures
C To increase power factor
D To reduce conductor resistance
Insulators isolate the conductor from the supporting structures, ensuring safe operation by preventing current leakage.
What is the main disadvantage of high-voltage transmission lines?
A Increased power losses
B High insulation costs
C Limited power capacity
D Increased system frequency
High-voltage lines require expensive insulation to prevent electrical breakdown and ensure safety, increasing overall costs.
Why are conductors stranded in transmission lines?
A To reduce corona discharge
B To improve mechanical flexibility and reduce skin effect
C To increase resistance
D To improve conductivity
Stranded conductors are more flexible and distribute current more evenly, minimizing the skin effect in AC systems.
What is the purpose of voltage regulation in a distribution system?
A To increase current flow
B To maintain a stable voltage under varying load conditions
C To decrease system frequency
D To reduce reactive power
Voltage regulation ensures that the voltage delivered to consumers remains constant despite changes in load or transmission conditions.
What is the main purpose of load balancing in a power system?
A To reduce energy losses
B To evenly distribute electrical load across all phases
C To increase conductor size
D To decrease capacitance
Load balancing ensures the efficient operation of the power system by minimizing phase imbalances and avoiding overloading.
What causes the Ferranti effect in transmission lines?
A High resistance in the line
B Line capacitance at light loads
C Excessive current flow
D Poor power factor
The Ferranti effect occurs when the capacitance of the line causes voltage rise at the receiving end under light-load conditions.
What is the function of a lightning arrester?
A To increase line voltage
B To protect the system from overvoltage due to lightning strikes
C To step down voltage levels
D To store energy
Lightning arresters divert high-voltage surges caused by lightning strikes safely to the ground, protecting equipment from damage.
What is the primary cause of reactive power in a power system?
A Inductive and capacitive loads
B Resistance of conductors
C Low system voltage
D High frequency
Reactive power is required to establish electric and magnetic fields in inductive and capacitive loads, which do not perform useful work but support system operation.
How does capacitance affect high-voltage, long-distance transmission lines?
A Increases line resistance
B Leads to Ferranti effect under light loads
C Reduces power losses
D Eliminates voltage fluctuations
Increased capacitance in transmission lines can cause a rise in receiving-end voltage under light load, known as the Ferranti effect.
What is the role of a microgrid in modern power systems?
A To step up voltage levels
B To operate independently or with the main grid for localized power supply
C To regulate transformer efficiency
D To store excess power
Microgrids are localized systems that provide power for small areas, ensuring reliability and incorporating renewable energy sources.
What is the primary cause of fault currents in a power system?
A Excessive capacitance
B Short circuits or insulation failures
C High power factor
D Voltage fluctuations
Fault currents arise from short circuits or insulation failures, which cause a large flow of current in the system.
What is the main advantage of using underground cables over overhead lines?
A Lower installation cost
B Better protection from environmental factors
C Higher power carrying capacity
D Easier maintenance
Underground cables are protected from weather-related hazards like wind, lightning, and falling trees, ensuring higher reliability.
What is the purpose of reactive power compensation in a transmission system?
A To increase active power
B To stabilize voltage levels and improve power factor
C To reduce system losses
D To increase system frequency
Reactive power compensation helps to maintain system voltage levels and optimize the power factor, improving system efficiency.
What is the role of a microgrid in modern power systems?
A To store power for future use
B To operate independently or with the main grid for localized power supply
C To regulate system voltage
D To reduce line resistance
Microgrids enhance power reliability and allow localized energy generation and storage, either in isolation or connected to the main grid.
What is the primary function of a lightning arrester in a power system?
A To step up voltage levels
B To protect the system from overvoltage caused by lightning
C To store energy
D To regulate frequency
Lightning arresters provide a path for lightning strikes to safely travel to the ground, protecting the electrical system from overvoltage damage.