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Module 3 Controllers Part 3 + Module 3 Controllers Part 2 + Module 2 Wind Turbine Performance-P Flashcards | StudBud
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Module 3 Controllers Part 3 + Module 3 Controllers Part 2 + Module 2 Wind Turbine Performance-P
Module 3 Controllers Part 3 + Module 3 Controllers Part 2 + Module 2 Wind Turbine Performance-P
120 terms
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Answers
1
The WindStats and Sindal reports recorded wind production data for over 6,000 turbines.
False
True
2
Which device is typically used as an output in a PLC system?
Proximity sensor
Motor
Limit switch
Timer
3
What happens when the rung in a PLC program is FALSE?
The output remains in the last state
The output is energized
The output is de-energized
A timer is always activated
4
Satellite images have been used to observe turbine wakes.
False
True
5
Disturbances in control systems are always intentional and desirable.
True
False
6
Wake effects can cause downstream turbines to lose up to 40% output.
True
False
7
In ladder logic, rung conditions must all be met for the output to be energized in series logic.
False
True
8
The Jensen-Katic model helps estimate power output directly.
False
True
9
Microcontrollers are well-suited for fast signal calculations like audio or video filtering.
True
False
10
What makes VAWTs different from HAWTs?
Higher towers
Take wind from any direction
Blade material
Higher lift
11
What is a major benefit of using dual-generator systems or variable pole switching?
Increased blade size
Lower tower costs
More consistent energy output
Increased turbine height
12
A wind turbine with a rotor diameter of 100 meters has a swept area of approximately 7,854 square meters.
True
False
13
A turbine with a high capacity factor always has a high specific output.
True
False
14
What is the role of the 'controller' in a feedback loop?
Disturb the system intentionally
Measure system outputs
Compare desired and actual values and issue control signals
Convert electrical signals to mechanical motion
15
Which controller type uses op amps and transistors for control?
ASIC
Analog controller
Digital controller
FPGA controller
16
Offshore wind turbines tend to have more consistent wind and higher capacity factors than onshore ones.
False
True
17
What is a typical programming method used for PLCs?
Assembly language
Python
Flowcharts
Ladder logic
18
In 2022, the same a 20 MW farm produced 55 GWh. What was the new CF?
33.5%
28.0%
35.0%
31.4%
19
Quick calc: If a turbine has a capacity factor of 0.7 and rated power of 2 MW, what is its AEP ?
10,000,000 kWh
8,760,000 kWh
17,520,000 kWh
12,264,000 kWh
20
Why do offshore wind farms usually have higher capacity factors?
More stable and consistent wind speeds
Larger foundations
Less maintenance
Better turbine design
21
What does the term "AEP" refer to in wind turbine performance?
Annual energy output
Generator efficiency
Rotor speed
Average blade torque
22
What happens when turbines are spaced too closely?
Noise is reduced
Output increases due to tighter grouping
Wake losses increase
Wind speed improves
23
In 1995, a 20 MW wind farm generated 35 GWh. What was the CF?
38.0%
32.5%
26.0%
20.0%
24
In the early 1980s–90s, wind turbine availability was limited to:
30–40%
75–85%
90–95%
50–70%
25
What does the yaw system control in a wind turbine?
Stop generator
Turn rotor to wind
Adjust pitch
Raise tower height
26
A 3×3 wind farm with 100 m turbines and standard spacing uses less 1,000,000 m² of land.(4D*7D)
True
False
27
Which of the following is the main reason wake effects reduce downstream turbine performance?
Noise generation
Blade pitch angle
Wind temperature
Increased turbulence and reduced wind speed
28
The Laplace transform of a ramp function (t) is 1/s .
True
False
29
In the control block diagram, 'K' represents the error signal.
True
False
30
Capacity factor increases when downstream wind speed decreases.
True
False
31
In an open-loop system, controlling actions are:
Independent of system output
Pre-programmed to feedback signals
Random
Dependent on system output
32
Scheduled maintenance improves reliability and reduces unplanned downtime.
True
False
33
Minicontrollers combine features of microcontrollers and additional peripherals for easier interfacing.
False
True
34
What is the primary advantage of using DSPs over microcontrollers?
Lower power consumption
Faster high-speed floating point operations
Smaller size
Easier programming interface
35
Which of the following is NOT a feature of PLCs?
Flexible and robust control
Ideal for graphic rendering tasks
Programmable using ladder logic
Designed for harsh environments
36
The Laplace transform converts time-domain problems into algebraic equations.
True
False
37
What does a higher capacity factor indicate?
Better utilization of wind resources
Higher maintenance frequency
More downtime
Lower energy output
38
The shower example in the slides illustrates feedback control.
True
False
39
Why do wakes recover faster offshore than onshore?
Higher towers
Stronger wind gusts
Larger turbines
More stable air and smoother surfaces
40
What caused low performance at Horns Rev in year 1?
Technical issues
Low wind
High wake loss
Poor site choice
41
The spacing between turbines does not impact energy production.
True
False
42
What kind of operation does a latching circuit perform?
Store the ON state until reset
Automatically reverse the output
Delay the output response
Generate pulses
43
Offshore wake recovery is faster due to fewer surface obstructions.
False
True
44
Which value of wake decay constant (k) is typical for offshore wind farms?
0.04
0.075
0.09
0.15
45
In grey-box modeling, some physical structure of the system is assumed known.
False
True
46
Which of the following methods is NOT used to study wake effects?
Field measurements
Wind tunnel testing
CFD modeling
Yaw control
47
In a closed-loop control system, what is 'e' typically called?
Plant output
Gain
Control signal
Error signal
48
What kind of layout typically reduces wake losses more effectively?
Random
Circular
Aligned
Staggered
49
A disturbance input, like a sudden wind gust, can be ignored in a robust closed-loop control design.
True
False
50
The actuator processes sensor data and makes decisions in a control system.
True
False
51
What is the 'plant' in a control system?
The sensor input
The physical system being controlled
The desired system behavior
The control algorithm
52
In the wind turbine example, what is the benefit of a closed-loop pitch control system?
Less complex system design
Lower maintenance cost
Real-time adjustment to wind gusts
Static response to wind changes
53
What is the primary purpose of a Programmable Logic Controller (PLC)?
Perform complex mathematical operations
Replace microcontrollers in embedded systems
Interface and control analog and digital devices in industrial environments
Simulate mechanical systems in real-time
54
PLC systems are commonly used in environments with dust, vibration, and temperature extremes.
False
True
55
The average design life of a wind turbine is around 10 years.
True
False
56
Higher wind variability results in more consistent average power output.
False
True
57
Which of the following is TRUE about Normally Closed (NC) inputs?
·A. They are open by default
They are closed by default and open when activated
They are closed by default and open when activated
They always energize an output
58
which event typically triggers the start of a timer during a forward-reverse motion cycle?
When the start button is pressed
When the actuator returns to its home position
When the emergency stop is reset
When the actuator reaches the end of its forward travel
59
What does annual energy production (AEP) measure?
Cost per kWh
Theoretical turbine capacity
Peak turbine power
Total energy output over a year
60
Yaw control can be used to steer wakes away from other turbines.
False
True
61
System identification can be based on white-box, grey-box, or black-box approaches.
False
True
62
Which system provides feedback to adjust its input automatically?
Manual loop
Open-loop
Closed-loop
Static system
63
What effect does feedback generally have on system performance?
Makes maintenance harder
Increases system noise
Improves accuracy and reliability
Decreases stability
64
Noise can only be introduced through the input of a control system.
True
False
65
Wind speed variability has no effect on capacity factor.
True
False
66
What type of system identification relies purely on experimental data without prior model knowledge?
Grey-box
Open-box
White-box
Black-box
67
Wind power output is proportional to:
Wind speed squared
Wind pressure
Wind speed cubed
Wind direction
68
An increase in wind speed consistency at a site is likely to improve the turbine's capacity factor.
True
False
69
What is the primary purpose of a Wind Energy Conversion System (WECS)?
Store mechanical energy
Increase wind speed
Convert kinetic energy of wind into mechanical and electrical power
Convert wind energy into solar power
70
Which of the following is NOT an advantage of an open-loop system?
Simplicity
High accuracy
Low cost
Low maintenance
71
What is the cut-out wind speed of a turbine used for?
Increase lift
Start the rotor
Stop in high wind
Switch blade pitch
72
Feedback systems use sensor measurements to influence future system behavior.
False
True
73
Rungs in ladder logic diagrams represent the flow of electrical current from left to right.
False
True
74
wind turbine produces 5,000 W with torque = 250 N·m. What is ω?
15 rad/s
20 rad/s
25 rad/s
10 rad/s
75
An FPGA is a type of analog controller.
False
True
76
In ladder logic, rungs represent the logical flow of current.
False
True
77
What is the typical cut-in speed for a modern wind turbine?
12 m/s
7–8 m/s
3–4 m/s
1 m/s
78
Which device measures a physical quantity and converts it into an electrical signal?
Controller
Sensor
Actuator
Plant
79
In a PLC ladder diagram, what do the vertical lines (rails) represent?
Power and ground
Signal amplifiers
Logical gates
Program start and end points
80
Predictive maintenance using real-time sensors is now a standard practice.
True
False
81
Constants multiplied by time functions in the time domain correspond to constants multiplied by Laplace functions.
True
False
82
Which component is responsible for acting on the plant to cause change?
Controller
Actuator
Sensor
Reference input
83
Which of the following is the Laplace transform of e
at
?
w/(s2+w2)
s/(s2+w2)
1/(s-a)
1/s
84
The closed-loop transfer function T(s) is given by C(s)G(s)/[1+C(s)G(s)K] .
True
False
85
Noise can be introduced at various points in a control system.
False
True
86
Specific output helps compare turbine efficiency based on rotor size.
True
False
87
Timers in PLCs can be used to delay or schedule specific output actions.
False
True
88
Which of the following introduces unexpected variations in a control system?
Noise
Feedback
Reference
Sensor
89
What is the 'reference' signal in a control system?
The actual output value
A signal representing the desired output
A feedback value
An error signal
90
Wind turbine wakes result in reduced wind speed and increased turbulence.
True
False
91
What is the recommended between-row spacing for minimizing wake losses?
4–6D
10–15D
2–4D
5–10D
92
. PLCs require the use of assembly language to program ladder logic.
False
True
93
What is G(s) in a control system?
Sensor signal
Input reference
Output voltage
Transfer function of the plant
94
What wind turbine component most directly affects specific output (kWh/m²)?
Rotor swept area
Tower height
Gearbox
Generator housing
95
Coastal and offshore sites are typically more variable than inland sites.
True
False
96
Quick calc: A row of 3 turbines each produces 17,520 kWh/year. What is the total row output?
58,000
35,040
52,560
38,000
97
Rated wind speed is the minimum wind speed required to start turbine rotation.
True
False
98
In the shower example, what serves as the actuator?
The shower head
The water heater
The brain
The hand adjusting the tap
99
What is the main purpose of using the Laplace Transform in control theory?
To simplify addition
To create more complex equations
To convert differential equations into algebraic equations
To simulate system errors
100
Which factor is NOT a key performance metric for wind turbines?
Annual energy production
Capacity factor
Availability
Fuel consumption
101
Increasing rotor swept area can improve capacity factor.
True
False
102
A PLC rung has two inputs in series: one NO and one NC. If only one input is active, what happens to the output?
The output remains OFF
The output enters a fault state
The output toggles
The output turns ON
103
A wind farm in Class 4 wind speed (>8.5 m/s) is considered excellent.
True
False
104
Which unit measures specific output?
RPM/W
m²/kWh
kWh/m²
Nm/rad
105
Block diagrams are graphical representations showing the signal flow between components.
False
True
106
A single-board computer often runs an operating system and supports high-level programming languages.
False
True
107
Analog controllers often use op amps for signal processing.
True
False
108
Capacity factor is the ratio of actual to theoretical maximum output.
True
False
109
Wind turbines must reach the cut-in speed before generating power.
True
False
110
If wind speed drops from 8.5 m/s to 7.3 m/s due to wake, what is the approximate capacity factor? (CF = (V/8.5)³)
0.65
0.80
0.95
0.5
111
NO contacts allow current to pass through when they are not activated.
True
False
112
What programming method is commonly used for PLCs?
Ladder logic
Python
C++
Assembly
113
Scroby Sands had lower CF than predicted due to:
Wake interference
Gearbox and generator faults
Weak winds
Short tower height
114
A programmable logic controller is suitable for office computing.
True
False
115
Availability measures the percentage of time a wind turbine is operational.
False
True
116
If a wind turbine has a high swept area but low energy production, its specific output will be high.
False
True
117
Modern wind turbines typically have availability ratings below 80%.
False
True
118
A plant is the control algorithm used in digital controllers.
True
False
119
A capacity factor of 50% means the turbine generates half of its rated power over the year.
True
False
120
Microcontrollers are typically embedded in systems requiring real-time control with limited resources.
True
False
