Question 1
Higher air density leads to higher power output.
A. TRUE
B. FALSE
View Answer
Answer: Option A
Explanation:
Higher air density results in higher output power. This is because denser air exerts more pressure on the wind blades which increases the speed of rotation. Thus, an increase in the speed of rotation increases output power.
Answer: Option A
Explanation:
Higher air density results in higher output power. This is because denser air exerts more pressure on the wind blades which increases the speed of rotation. Thus, an increase in the speed of rotation increases output power.
Question 2
Higher wind speeds _________ the speed of rotation of the wind blades.
A. increase
B. decrease
C. monotonically decrease
D. first increase and then decrease
View Answer
Answer: Option A
Explanation:
Higher wind speeds increase the speed of rotation of the wind blades. This in turn generates more output power as the net mechanical energy increased due to increase in rotational speed of the wind blade.
Answer: Option A
Explanation:
Higher wind speeds increase the speed of rotation of the wind blades. This in turn generates more output power as the net mechanical energy increased due to increase in rotational speed of the wind blade.
Question 3
How does the output power vary between cut-in speed and the rated speed?
A. cubically
B. linearly
C. square
D. exponential
View Answer
Answer: Option A
Explanation:
Between the cut-in speed and the rated speed, the output power of the wind turbines varies cubically. The output power cubically increases until the rated speed is reached – if the wind speed doubles, the output power increases by 8 times.
Answer: Option A
Explanation:
Between the cut-in speed and the rated speed, the output power of the wind turbines varies cubically. The output power cubically increases until the rated speed is reached – if the wind speed doubles, the output power increases by 8 times.
Question 4
In a substation, the wind power plant line is connected to a _______ voltage bus bar.
A. high
B. low
C. mini
D. medium
View Answer
Answer: Option D
Explanation:
In a substation, the wind power plant line is connected a medium voltage bus bar. A medium voltage bus bar is used for medium voltages – 10kV to 50kV. At the wind turbine generator, this bar is connected to a step up transformer which steps up the output of the generator from 0.69kV to 11kV or 33kV.
Answer: Option D
Explanation:
In a substation, the wind power plant line is connected a medium voltage bus bar. A medium voltage bus bar is used for medium voltages – 10kV to 50kV. At the wind turbine generator, this bar is connected to a step up transformer which steps up the output of the generator from 0.69kV to 11kV or 33kV.
Question 5
Lower wind speeds result in ________
A. higher wind energy obtained
B. no wind energy obtained
C. lower wind energy obtained
D. 100% energy conversion for half the operation time and less than 10% energy conversion for the remaining half of the operation time
View Answer
Answer: Option C
Explanation:
Wind speeds disproportionally affect the electricity generation from wind turbines. Lower wind speeds result in much lower wind energy. This further decreases the conversion efficiency resulting in extremely low powers.
Answer: Option C
Explanation:
Wind speeds disproportionally affect the electricity generation from wind turbines. Lower wind speeds result in much lower wind energy. This further decreases the conversion efficiency resulting in extremely low powers.
Question 6
Network-wide plans in wind energy grid integration include _______
A. system impact studies done for a specific wind project
B. materials used to manufacture wind turbine blades
C. developing grid code
D. solar panel manufacturing plant
View Answer
Answer: Option C
Explanation:
Network-wide plans include development of grid code, network-wide system integration studies with scenarios for different levels of wind penetration and system operation studies. They are not done for a specific wind project.
Answer: Option C
Explanation:
Network-wide plans include development of grid code, network-wide system integration studies with scenarios for different levels of wind penetration and system operation studies. They are not done for a specific wind project.
Question 7
Power output is not related to the local air density.
A. FALSE
B. TRUE
View Answer
Answer: Option A
Explanation:
Power output is related to the local air density. Air density is defined as the mass per unit volume of the earth’s atmosphere. It depends on various physical factors.
Answer: Option A
Explanation:
Power output is related to the local air density. Air density is defined as the mass per unit volume of the earth’s atmosphere. It depends on various physical factors.
Question 8
What are the two types of planning activities related to grid integration?
A. Network-wide and project-specific
B. BJT and MOSFET
C. Rotor and shaft
D. Low power and high power designs
View Answer
Answer: Option A
Explanation:
The two types of planning activities related to grid integration are network-wide and project-specific activities. BJT and MOSFET are electronic/electrical devices (components). Rotor and shaft are used in a rotating mechanism. Low power and high power designs are circuit design specifications.
Answer: Option A
Explanation:
The two types of planning activities related to grid integration are network-wide and project-specific activities. BJT and MOSFET are electronic/electrical devices (components). Rotor and shaft are used in a rotating mechanism. Low power and high power designs are circuit design specifications.
Question 9
What are the types of grid integration costs?
A. Transmission extension, volatility balancing, covering peak load
B. Marginal cost
C. Fixed cost
D. Fundamental Analysis
View Answer
Answer: Option A
Explanation:
Grid integration costs are divided into three categories – transmission extension, balancing of increased volatility in grid and covering the peak load. The other options are various terms used in economics and finance to define different types of costs. They are not particularly related to grid integration.
Answer: Option A
Explanation:
Grid integration costs are divided into three categories – transmission extension, balancing of increased volatility in grid and covering the peak load. The other options are various terms used in economics and finance to define different types of costs. They are not particularly related to grid integration.
Question 10
What happens to the output power when the wind turbine blades rotate faster for the entire operation time?
A. The output power first increases then decreases
B. The output power first decreases then monotonically increases
C. The output power decreases
D. The output power increases
View Answer
Answer: Option D
Explanation:
When the wind turbine blades rotate faster for the entire operation time, the output power increases. The output power increases until the speed of rotation is decreased.
Answer: Option D
Explanation:
When the wind turbine blades rotate faster for the entire operation time, the output power increases. The output power increases until the speed of rotation is decreased.
Question 11
What happens to wind speed when many turbines operate collectively?
A. Wind speed reduces
B. Wind speed increases
C. Wind speed does not change
D. Wind speed increases exponentially and then decreases linearly
View Answer
Answer: Option A
Explanation:
Wind turbines are used to extract kinetic energy from the incoming wind. When multiple turbines operate collectively, the wind speed of the atmospheric flow reduces after crossing each turbine. This affects the efficiency of the turbines.
Answer: Option A
Explanation:
Wind turbines are used to extract kinetic energy from the incoming wind. When multiple turbines operate collectively, the wind speed of the atmospheric flow reduces after crossing each turbine. This affects the efficiency of the turbines.
Question 12
What is a grid code for wind energy integration?
A. A binary code
B. A hexadecimal code
C. A code of conduct
D. A rulebook specifying generator properties
View Answer
Answer: Option D
Explanation:
A grid code for integration is a rulebook that specifies properties of generators and other equipment used to connect to the grid. The equipment must satisfy these properties to ensure reliable and safe operation.
Answer: Option D
Explanation:
A grid code for integration is a rulebook that specifies properties of generators and other equipment used to connect to the grid. The equipment must satisfy these properties to ensure reliable and safe operation.
Question 13
What is a power flow study in wind energy integration?
A. A binary code
B. Determines flow of electrical energy from generators to consumers
C. Determines flow of electrical energy from generators to consumers meeting line loading requirements
D. A study specifying generator properties
View Answer
Answer: Option C
Explanation:
A power flow study in wind energy integration determines flow of electrical energy from generators to consumers meeting line loading requirements and all grid code requirements. It is performed using various power systems modelling software like PSS/E and ETAP.
Answer: Option C
Explanation:
A power flow study in wind energy integration determines flow of electrical energy from generators to consumers meeting line loading requirements and all grid code requirements. It is performed using various power systems modelling software like PSS/E and ETAP.
Question 14
What is cut-in wind speed?
A. Wind turbine stops generating output power
B. Wind turbine starts generating output power
C. Wind turbine stops functioning
D. Wind turbine starts functioning
View Answer
Answer: Option B
Explanation:
Wind turbines are designed to operate within a specific range of wind speeds. The cut-in wind speed is that wind speed at which the wind turbine starts generating output power. It is not the speed at which the turbine starts functioning.
Answer: Option B
Explanation:
Wind turbines are designed to operate within a specific range of wind speeds. The cut-in wind speed is that wind speed at which the wind turbine starts generating output power. It is not the speed at which the turbine starts functioning.
Question 15
What is feather of wind turbine blades?
A. Adding feathers to the blades
B. Reducing the weight of wind turbine blades
C. Reducing the angle of pitch
D. Increasing the angle of pitch
View Answer
Answer: Option D
Explanation:
Increasing the angle of pitch is called feathering of wind turbine blades. It is achieved by turning the blades to orient them in a direction parallel to the air flow. This minimized the net drag on the wind turbine blades.
Answer: Option D
Explanation:
Increasing the angle of pitch is called feathering of wind turbine blades. It is achieved by turning the blades to orient them in a direction parallel to the air flow. This minimized the net drag on the wind turbine blades.
Question 16
What is grid integration of wind energy?
A. Planning the connection of wind power plant to the grid
B. Physical connection of wind power plant to the grid
C. Energy sent from grid to run the wind turbines
D. Collection of all activities related to connecting wind power plants to the grid
View Answer
Answer: Option D
Explanation:
Grid integration of wind energy is simply the collection of all activities related to connecting wind power plants to the grid. The wind power plant sends energy to the grid. It does not consume energy from the grid.
Answer: Option D
Explanation:
Grid integration of wind energy is simply the collection of all activities related to connecting wind power plants to the grid. The wind power plant sends energy to the grid. It does not consume energy from the grid.
Question 17
What is project specific planning in wind energy grid integration?
A. Planning activities for a solar panel system
B. Planning activities for all the future wind power plants
C. Planning activities related to a unique wind project
D. Planning activities for the maintenance of the existing thermal power plants
View Answer
Answer: Option C
Explanation:
Project specific planning activities in wind energy grid integration are planning activities related to a unique wind project. They include system impact studies done for a specific wind project. The input for this type of study is the wind power plant which is being studied.
Answer: Option C
Explanation:
Project specific planning activities in wind energy grid integration are planning activities related to a unique wind project. They include system impact studies done for a specific wind project. The input for this type of study is the wind power plant which is being studied.
Question 18
What is rated speed?
A. Wind turbines generate least output power
B. Wind turbines do not generate any output power
C. Wind turbines generate maximum output power
D. Wind turbines have no rated speed as the output power always increases
View Answer
Answer: Option C
Explanation:
The rated wind speed is that wind speed at which the wind turbines generate maximum output power. Maximum power point tracking (MPPT) is used to ensure that the wind turbines always operate in the neighbourhood of the rated wind speed.
Answer: Option C
Explanation:
The rated wind speed is that wind speed at which the wind turbines generate maximum output power. Maximum power point tracking (MPPT) is used to ensure that the wind turbines always operate in the neighbourhood of the rated wind speed.
Question 19
What is the cut-out speed?
A. Wind turbine starts generating output power
B. Wind turbine must be shut down
C. Wind turbine stops functioning
D. Wind turbine starts functioning but does not generate output power
View Answer
Answer: Option B
Explanation:
Cut-out speed is the wind speed at which the wind turbine must be shut down. This prevents damage to the equipment used in the wind turbines. The cut-out speed is decided prior to wind turbine construction.
Answer: Option B
Explanation:
Cut-out speed is the wind speed at which the wind turbine must be shut down. This prevents damage to the equipment used in the wind turbines. The cut-out speed is decided prior to wind turbine construction.
Question 20
Which of the following are a few primary tests performed after commissioning phase in the physical connection stage?
A. Switch-gear functioning and quality parameters
B. Feathering
C. Wind turbine blade tests
D. Rotor and shaft tests
View Answer
Answer: Option A
Explanation:
Testing the functioning of switch-gear, quality parameters like harmonics and flicker, proper start-up and shut down are crucial during grid integration. Feathering of blades is done to prevent the blades from being damaged by storm winds. Wind turbine blade, rotor and shaft tests do not come under grid integration tests.
Answer: Option A
Explanation:
Testing the functioning of switch-gear, quality parameters like harmonics and flicker, proper start-up and shut down are crucial during grid integration. Feathering of blades is done to prevent the blades from being damaged by storm winds. Wind turbine blade, rotor and shaft tests do not come under grid integration tests.
Question 21
Which of the following are impacts of grid integration of wind power plant?
A. Day-ahead unit commitment process
B. Day-ahead unit commitment process, economic dispatch process
C. Generator types
D. Rotor and shaft tests
View Answer
Answer: Option B
Explanation:
The unit commitment process is cost-effective combination of generating units to meet forecasted load and reserve requirements, while adhering to generator and transmission constraints. Economic dispatch is the optimization of production from generators to minimize cost of generation while meeting all the constraints. In most grids, wind energy has the highest priority due to its low marginal costs.
Answer: Option B
Explanation:
The unit commitment process is cost-effective combination of generating units to meet forecasted load and reserve requirements, while adhering to generator and transmission constraints. Economic dispatch is the optimization of production from generators to minimize cost of generation while meeting all the constraints. In most grids, wind energy has the highest priority due to its low marginal costs.
Question 22
Which of the following are the limits of the range of wind speeds for which the turbines are designed?
A. Elasticity
B. Threshold voltage
C. Networking
D. Cut-in speed and cut-out speed
View Answer
Answer: Option D
Explanation:
Since wind turbines are designed to operate within a specific range of wind speeds, they have limits. The lower limit is called the cut-in speed and the upper limit is called the cut-out speed. Elasticity is the ability of a material to come back to its original shape after stretching. Threshold voltage is related to electrical devices like diodes, BJTs, etc.
Answer: Option D
Explanation:
Since wind turbines are designed to operate within a specific range of wind speeds, they have limits. The lower limit is called the cut-in speed and the upper limit is called the cut-out speed. Elasticity is the ability of a material to come back to its original shape after stretching. Threshold voltage is related to electrical devices like diodes, BJTs, etc.
Question 23
Which of the following depicts the correct order of the stages involved in grid integration of wind energy?
A. System operations → physical connection → planning
B. Planning → system operations → physical connection
C. Planning → physical connection → system operations
D. Physical connection → planning → system operations
View Answer
Answer: Option C
Explanation:
Grid integration of wind energy consists of three stages starting with planning the connection. After laying out the plan, the power plant is physically connected to the substation (grid). Lastly, the functioning of each system is handled under systems operation.
Answer: Option C
Explanation:
Grid integration of wind energy consists of three stages starting with planning the connection. After laying out the plan, the power plant is physically connected to the substation (grid). Lastly, the functioning of each system is handled under systems operation.
Question 24
Which of the following does the local air density depend upon?
A. Soil
B. Lightning
C. Altitude and pressure
D. Nitrogen and oxygen
View Answer
Answer: Option C
Explanation:
Air density depends on altitude, pressure and temperature. It does not depend on soil and its topography as well as on lightning. Nitrogen and oxygen are types of gases and are components of air.
Answer: Option C
Explanation:
Air density depends on altitude, pressure and temperature. It does not depend on soil and its topography as well as on lightning. Nitrogen and oxygen are types of gases and are components of air.
Question 25
Which of the following is a reason for variable wind speed?
A. Water
B. Earth’s rotation
C. Electrons
D. Fans
View Answer
Answer: Option B
Explanation:
Day and night cycle caused by earth’s rotation and seasonal changes due to tilt axis of earth cause changes in wind speed. Water, electrons and fans do not affect wind speed.
Answer: Option B
Explanation:
Day and night cycle caused by earth’s rotation and seasonal changes due to tilt axis of earth cause changes in wind speed. Water, electrons and fans do not affect wind speed.
Question 26
Which of the following is true?
A. More than 50% of the land area on earth can generate 1W per square meter
B. Less than 5% of the land area on earth can generate 1W per square meter
C. 60 – 80% of the land area on earth can generate 1W per square meter
D. More than 80% of the land area on earth can generate 1W per square meter
View Answer
Answer: Option B
Explanation:
After multiple simulations, research has shown that less than 5% of land area can actually generate 1W per square meter. A global climate model was used to simulate scenarios of different wind energy across all continents.
Answer: Option B
Explanation:
After multiple simulations, research has shown that less than 5% of land area can actually generate 1W per square meter. A global climate model was used to simulate scenarios of different wind energy across all continents.
Question 27
Which of the following is/are good practices for grid integration of wind power plant?
A. Day-ahead unit commitment process
B. Day-ahead unit commitment process, economic dispatch process
C. Optimized transmission from resources-rich areas to load, flexible generation
D. Rotor and shaft tests
View Answer
Answer: Option C
Explanation:
Optimizing transmission from resource-rich areas to load saves both, power and costs. Using the under-utilized line to transmit power instead of setting a new transmission line is an example of optimization. Flexible power generation helps meeting in varying power demands.
Answer: Option C
Explanation:
Optimizing transmission from resource-rich areas to load saves both, power and costs. Using the under-utilized line to transmit power instead of setting a new transmission line is an example of optimization. Flexible power generation helps meeting in varying power demands.
Question 28
Why is feathering of wind turbine blades required?
A. To increase drag
B. To reduce drag
C. To prevent the blades from being destroyed by strong winds
D. To extract power from strong winds originating from storms
View Answer
Answer: Option C
Explanation:
Feathering of wind turbine blades is used to prevent the blades from destruction by storm winds. By orienting the wind blades in a direction parallel to the incoming air flow, the net drag from a stopped propeller is minimized and the system is shut down.
Answer: Option C
Explanation:
Feathering of wind turbine blades is used to prevent the blades from destruction by storm winds. By orienting the wind blades in a direction parallel to the incoming air flow, the net drag from a stopped propeller is minimized and the system is shut down.
Question 29
Why is the energy output of wind power plant variable?
A. Wind speed is variable
B. Wind speed is an unknown constant
C. Wind speed is known constant
D. Poor equipment is used
View Answer
Answer: Option A
Explanation:
The energy output of any wind power plant (WPP) is variable because the wind speed is variable. The equipment used in power plant is designed to deal with such variability and uncertainty.
Answer: Option A
Explanation:
The energy output of any wind power plant (WPP) is variable because the wind speed is variable. The equipment used in power plant is designed to deal with such variability and uncertainty.