Wind Turbine operation & Maintenance.pptx

Wind turbine overview and real time data of 60MW wind plant

1. Operation and Maintenance of Wind Turbines Speakers Abdullah Aftab Asjad Ali ( O&M Engr SGRE ) (O&M Engr SGRE)

2. Introduction • Wind turbines - a successful technology for clean and safe production of electricity. • Fastest growing renewable energy source. • Globally recognized as environment friendly and sustainable. • Emerging as a economically competitive source of energy. • Wind energy will never run out, and is very helpful in mitigating CO2 production.

3. Wind as a source of energy Wind is air in motion. It has a mass. A mass in motion has a momentum Momentum is a form of energy that can be harvested. Wind energy relies on sun. Wind is created by uneven heating of the earth’s surface.

4. Global creation of Winds Uneven heating of the earth's surface. When sun hits one part of the earth more directly, it warms that part up. The warm air rises and cooler air rushes in, creating wind.

5. Kinetic Energy in the Wind Kinetic Energy = Work = ½mV^2 Where: M= mass of moving object V = velocity of moving object What is the mass of moving air? density (ρ) x volume (Area x distance) = ρ x A x d = (kg/m3 ) (m2 ) (m) = kg

6. Power in the Wind Power = Work / time = Kinetic Energy / time = ½mV2 / t = ½( ρ Ad)V2 /t = ½ ρ AV2 (d/t) = ½ ρ AV3 d/t = V Power in the Wind = ½ ρ AV3

7. Power in the Wind = ½ρAV3 Swept Area – A = πR2 (m2 ) Area of the circle swept by the rotor. ρ = air density – in Pakistan its about 1.225-kg/m3.

8. The Betz Limit A maximum of 59.26% of the available wind power can be converted to mechanical power at ideal conditions

9. Wind Energy Conversion

10. Power Conversion

11. Vertical Axis Wind Turbines

12. Horizontal Axis Wind Turbines Commercially used More Stable More Reliable Produce greater Energy compared to vertical axis

13. Mechanical-Electrical Single Line Diagram

14. Components of Wind Turbine

15. Wind Turbine Components Rotor, or blades, which convert the wind's energy into rotational shaft energy. Nacelle (enclosure) containing a drive train, usually including a gearbox (Some turbines operate without a gearbox) and a generator. Tower, to support the rotor and drive train. Electronic equipment such as controls, electrical cables, ground support equipment, and interconnection equipment.

16. Wind Turbine Components Rotor Comprises of all turning parts of the unit outside the nacelle Rotor Blade The hub Blade pitch mechanism

17. Rotor Blades Blades Blades sweep around air and further rotate shaft which in turn rotates generator rotor.

18. Real Time Blade Pitched at 87 degrees

19. How Does Turbine Rotates?

20. Turbine Power

21. Power Control of Turbine Power Control through Aerodynamic (Angle of attack, Pitch angle, Lift & Drag) Stall control Pitch control

22. Power Control of Turbine Pitch Control Pitch controls adjust the blades in wind turbines by rotating them so that they use the right fraction of the available wind energy to get the most power output, all the while ensuring the turbine does not exceed its maximum rotational speed. This maintains the turbine’s safety in the event of high winds, loss of electrical load, or other catastrophic events.

23. Stall Control Blades are fixed at a specific pitch angle and start to stall in case of high wind

24. ROTOR BLADE-MATERIAL Materials Al, Titanium, Steel, Fiber reinforced composite material Fiber reinforced composite Material blades currently used in almost all WT structure Types: Glass fiber Carbon fiber Organic aramid fiber (Kevlar) Mostly used is glass fiber -Strength properties are extraordinarily high

25. Carbon fibers Has longest tearing strength High modules of elasticity The stiffness of carbon fiber components is comparable to that of steel Fatigue properties are good

26. Number of Blades Most common design is the three-bladed turbine. The most important reason is the stability of the turbine. A rotor with an odd number of rotor blades (and at least three blades) can be considered to be similar to a disc when calculating the dynamic properties of the machine. A rotor with an even number of blades will give stability problems for a machine with a stiff structure. The reason is that at the very moment when the uppermost blade bends backwards, because it gets the maximum power from the wind, the lowermost blade passes into the wind shade in front of the tower.

27. Hub Of Turbines A ll major parts fixed relative to the main shaft in which blade pitch can be varied no other blade motion is allowed The main body of the rigid hub casting or weldment to which the blades are attached.

28. Inner Hub of Wind Turbines

29. Inner Hub of wind turbines

30. Drive Train Complete wind turbine drive train consist of all the rotating components 1. Main shaft 2. Coupling 3. Gearbox 4. Brake 5. Generator

31. Shaft C ylindrical element designed to rotate T ransmit torque Attached to the gear pulley and couplings Wind turbine shafts are especially found in gearboxes, generators and linkages.

32. MAIN SHAFT / LOW SPEED SHAFT / ROTOR SHAFT T ransfer torque from the rotor to the rest of the drive train and transfer of all other loads to the nacelle structure Supports the weight of the rotor Made of steel

33. Low Speed Shaft

34. High Shaft Connecting shaft of the gearbox outlet to the electric generator rotates with nominal speed of 1500 RPM F itted with flexible coupling at each end to cater for small misalignment between generator and gearbox

35. High Speed Shaft

36. PLANETARY GEARBOX Input and output shafts are co-axial There are multiple pairs of gear teeth meshing at anytime Loads on each gear reduced

37. Planetary Gearbox Planet carrier rotates with the same carrier arm rotational speed of the rotor blades Three planet wheel turn around inner circumference of the ring wheel Increase the speed of the sun wheel Advantages : Always three gear wheels supporting each other and that all gear wheels are engaged at the time in principle it only needs to about a 1/3 of the size

38. Doubly fed induction generator

39. Doubly FED Induction generator-Super synchronous Operation

40. Synchronizing with frequency

41. Doubly fed induction generator The configuration known as DFIG (Double fed induction generator) correspond to the WRIG (Wound rotor induction generator) with partial scale frequency converter The partial scale frequency converter performs the reactive power compensation and ensures smoother grid connection The generator has a wider range of speed control, e.g., (-40% to +30%) around the synchronous speed (wider than OptiSlip ) The use of slip rings and protection in case of grid faults is a major drawback Variable speed operation is obtained by injecting a controllable voltage into the rotor at the desired frequency

42. Doubly fed I.G Advantages and disadvantages Advantages Reduced-capacity converter (cost, efficiency) Decoupled control of active/reactive power Smooth grid connection Disadvantages Regular maintenance of slip ring and gearbox Limited fault ride-through capability

43. Synchronous Generator and Carbon Brushes Slip Ring and Carbon Brushes

44. Control and Protection systems Increasing use of advanced electronics for Generator, converter and power control Pitch system Start, stop and sequencing Surveillance

45. Why do we need a control! T he primary energy source is non linear and unpredictable. Increase in wind speed develops an enormous power in rotor – To be optimized To transfer the electrical power to the grid at an imposed level, for wide range of wind velocities. To meet power quality requirements To detect the abnormal conditions and preventing the wind turbine from possible dangerous situations Achieve desired function and Safe Operation

46. Control system Control system consists of Various sensors, Transducers and Limit switches (input) PLC (Process) Circuit breakers, Converters, contactors and relays (output) Set point list

47. Important functions of Control system Alignment to the wind by Yawing Start-up and shutdown procedure Connection of the electrical load Rotor speed Control Power limitation Cable twist limits Temperature control

48. General Sequence

49. PROTECTION SYSTEM Over-speed Generator overload or fault Excessive vibration Abnormal cable Twist

50. NACELLE The nacelle cover is the wind turbine housing Protects turbine components from weather Reduces emitted mechanical sound Material G-FRC glass-fiber reinforced composite materials On larger Machines it has a hole that it can be entered personal for inspector (or) maintains the internal components.

51. Inside of a Nacelle

52. Inside of a nacelle

53. Main Frame Transfer the rotor loading to the yaw bearing and to provide mountings for the gearbox and generator Either welded beam or casted

54. Yaw Control Rotate the nacelle with respect to the tower on its slew bearing K eep the turbine facing in the wind Unwind the power and other cables – Wind Vane on nacelle tells controller which way to point rotor into the wind – Yaw drive turns gears to point rotor into wind

55. Yaw Drive Rotate the nacelle with respect to the tower on its slew bearing Keep the turbine facing in the wind unwind the power and other cables

56. Yaw clamps and Yaw Drive Yaw clamps acts as brea k and keep the nacelle at fixed position.

57. Converter Cabinet A power electronic converter enables efficient conversion of the variable frequency output of an induction generator, driven by a variable speed wind turbine, to a fixed frequency appropriate for the grid or a load.. All the power is transmitted to the grid through the converter. The converter tracks the frequency and phases of grid voltage to keep the output current and frequency of turbines in consistent with those of the grid

58. Converter Cabinet

59. Tower Made from tubular steel, the tower supports the structure of the turbine. Towers usually come in three sections and are assembled on-site. Because wind speed increases with height, taller towers enable turbines to capture more energy and generate more electricity.

60. Towers Towers are stacked upon one another Mostly there are more than one parts of a tower fastened to one another with huge bolts

61. Operations and Maintenance of Turbines Maintenance of wind turbines involve Tensioning of blades bolts Torquing of all the towers bolts, main frame, main shaft disc, generator feet etc. Greasing of Generator, yaw teeth's. Cleaning of Fiber and Platforms

62. Tensioning of blades During Tensioning of Blades a pressure of 1000 bar using a Tensioner pump is given and bolts are tightened that are loose before any catastrophe happens. When pressure is applied on the bolt, the tensioner pulls the bolt upwards and using ratchet bolts are tightened. Precautions are important when dealing with such high pressure, a little mistake can put your or others life in jeopardy.

63. Torquing of bolts Using different Keys at different pressures, the bolts in the tower and inside the nacelle are tightened For the first tower, the pressure is 425 bar and 400 bar onwards for remaining, the yaw tower is tightened at 374 bars. Inside the nacelle, the bolts of main frame are tightened at 500 bars and there are different pressures for other bolts. Different RT’s mainly RT 5, RT3 and RT2 are used with different key sizes mainly 36, 27, 46 depending upon the size of bolt.

64. Greasing of blades, yaw teeth and Generator and cleaning Greasing of yaw teeth, Blades and generator is done after 3 months and 6 months. This is known as 3M/6M maintenance. Cleaning of wind turbine is very important as the dirt particles can lead to a lot of warnings and alarming situations on turbine.

65. Operations in Wind Turbine There are number of alarms that can occur on turbine, and they are the major reason for availability loss of any wind turbine. So, it is very important to keep the turbine on going and available for power production. Some alarms are removed using SCADA, but some are removed by fixing the fault or any intricacy on turbine.

66. SCADA Real time instantaneous data of wind turbines is monitored an analyzed. Any abnormality is observed and removed. Operators monitor wind turbine production 24/7.

67. Total Wind Capacity of Pakistan Currently, 1836 MW of power is being produced from wind in Pakistan while Pakistan has more than 132 ,000 MW capacity on wind including both off shore and on shore. The recent wind Plants that are set up in Pakistan has each turbine with capacity of 2.1 MW power production. Wind is the second most biggest source of clean energy in the World.

68. Wind Map of Pakistan

69. THANKS For Your Time