Noise issues for offshore windfarms – basic acoustics: what needs to be measured and why Underwater bioacoustic research Low frequency ground roll waves created during piling Dick Hazelwood, R&V Hazelwood Associates LLP, UK Offshore construction noise and the modelling of pile behaviour and noise reduction techniques
Pre- and post-construction measurements Sound power measurements according to IEC 61400-11 Tomas Hansen, Team Leader, Noise and Vibration Measurements, Siemens Wind Power A/S, Denmark The French approach to noise assessment Far field effects like amplitude modulation, tonality and impulses
Low-noise wind turbine design Aeroacoustic noise sources and their characterisation Design of wind turbine gearboxes with respect to noise
Survey of noise regulations and guidelines across the EU Angeliki Koulouri, Research Officer, European Wind Energy Association – EWEA, Belgium Affective response to noise from wind turbines Sabine von Hunerbein, University of Salford, UK https://www.linkedin.com/in/sabine-von-h%C3%BCnerbein-29887211/ Noise impacts: is wind turbine noise really so different from other types of environmental noise Ian Flindell, Institute of Sound…
Electromagnetism Fundamentals Electric Charge The most fundamental quantity in electricity is electric charge. Energy transfer is accomplished by the motion of charge. Circuit In electricity, the path through which charge flows is called a circuit. Current The rate of motion of charge in a circuit is called current. The unit of current is the ampere…
Wind Turbine Parts The principal parts of a modern wind turbine are the rotor, hub, drive train, generator, nacelle, yaw system, tower, and power electronics. Both the Horizontal Axis Wind Turbine (HAWT) and the Vertical Axis Wind Turbine (VAWT) have similar sub-systems, except that the VAWTS do not have a yaw system, as they are…
The most used wind turbine nowadays has 3 blades. As the blades work in rotational motion, they cannot have different weights, so that there is no imbalance between the mechanical loads applied to the turbine. The unbalance can cause vibration in the turbine, in addition to repetitive efforts thatcause fatigue in the turbine and reduce…
Bearings are parts that support and guide rotating or oscillating elements, such asaxles or wheels, and transfer loads between machine components. They offer reduced friction and therefore allow high rotational speeds while reducing noise,heat, energy consumption, and wear. No matter the model of wind turbine, bearings are often a problem in all of them. The…
The main damages during the lifetime of a wind turbine are caused by: General Wear Delamination can happen in wind blades, where a detachment of the intra and extrados shellscan be seen. Usually associated with leading edge erosion. Fatigue Loads It is the phenomenon of progressive rupture of materials subjected to repeated cycles of stress…
Wind turbine blades are remarkable feats of engineering, transforming the power of the wind into clean electricity. The materials they are made from and the methods used to construct them have a profound impact on their power output, longevity, and overall sustainability. The ideal blade is made from strong yet lightweight materials that can withstand…
Production Bottleneck A bottleneck is a point where the production line “locks up”, causing tasks not to be happen as expected. The bottleneck prevents the continuity of production or causes it to happen at a speed much lower than necessary. Often, bottlenecks are caused by a lack of knowledge of the production process. Tips to…
Manufacturing defects in wind turbine blades are Dry Spots It can be dry spots and even large whitish areas, which show the lack of resin in the laminate.Glass fibers are dry because they have not been properly impregnated with resin. Excess Resin Regions with excess resin are more fragile and can crack more easily, in…
Lamination Historically, wind turbine blades (made of thermoset resin and fiberglass as well as other composite materials) were manufactured using the hand-lay-up process. The disadvantage of manual lamination is the difficulty of properly controlling the amount of resin in the laminate. Excess resin compromises the mechanical performance of the part, leaving it fragile and heavy….
Sandwich structures made from balsa wood have been used in composite materials around theworld for over 40 years. Balsa wood is called the core material, as it has the function of providing structural filling in the wind turbine blade. it is made from blocks of wood cut across the grain of the wood. The purpose…
Core (Foam) Structural Used as reinforcement of “sandwich” composite materials, as it is rigid, light, and highly durable.It has been used in the composites industry for over 45 years in the manufacture of boats, planes, trucks, automobiles, wind turbine blades, building panels, etc. PET Foam (Polyethylene Terephthalate) It can be found in virgin or recycled…
Peel-ply fabrics are indispensable materials in the manufacturing process of wind turbine blades. Peel ply is the name of the synthetic fabric that is placed on the surface of the composite of fibers and resin, in the vacuum infusion process or vacuum bag. Peel ply fabrics are generally made of polyamide (nylon) or polyester, in…
Wind Turbines are made of composite materials. The materials that form this composite are Resin Usually epoxy or polyester resin Fiberglass Balsa Wood Structural Foam Usually PVC Carbon Fibre
Composite Materials It is a macroscopic combination of two or more distinct materials, which will make the composite possess superior and unique properties in relation to the individual properties of its constituents. Composites are obtained by making combinations between materials from different families. Example: Composites are a number of layers (laminas) bonded by a resin…
Polymers can be classified, in terms of fusibility, into thermoplastics or thermosets (thermosets). Thermoplastic polymers melt on heating and solidify on cooling, in a reversible process. They can also be dissolved in suitable solvents. Examples: PET (from beverage bottles), PS (from disposable cups), LDPE (from plastic bags), PVC (from sewage pipes). Thermosetting polymers, by heating…
What are Polymers? Polymers are a combination of two words poly means many and mers means partsThey are long-chain molecules (macromolecules) composed of many repeating parts (monomers). All polymers are macromolecules, but not all macromolecules are polymers, as not all macromolecules have a monomer (a repeating unit) in their structure, as in the case of…
Video : Wind Turbine Yaw Movements and Gyroscopic Forces Under normal operational conditions, yaw movement may occur when the rotor is stopped or when it is turning. When the rotor is stopped, the force applied by the yaw drive needs to overcome only the inertia of the nacelle and the frictional forces at the yaw…
While the rotation of the rotor of the wind turbine can be slowed by changing the pitch angle of the blades during aerodynamic braking, the rotor needs a mechanical main shaft brake to keep it stopped completely. Frictional force is an essential physics concept that will help explain the working mechanism of the main shaft…
When a gearbox vibrates as a whole, the severity of the vibration can be detected at the outer surface of the gearbox housing. While some vibration is normal, higher levels of vibration can be caused by the wearing or failure of the gearbox components. For this reason, gearboxes often incorporate vibration sensors to detect conditions…
Three different types of forces act on gears and bearings in a gearbox. They are gravitational forces, frictional forces, and contact forces. The most significant are contact forces, due to the magnitude of the contact stresses that these forces are generating on the surfaces of the moving parts during operation. Contact force occurs when the…
Heat is generated during the operation of the gearbox due to friction between the solid surfaces of the moving parts. Most of the heat is generated by the friction between the gear teeth, and between the rollers and rings of the bearings. Depending on the type of the engaging gears, the input torque and speed,…
The blades, the hub, and the main shaft of a wind turbine harness the kinetic energy of the wind and convert it into rotational mechanical energy. The speed of this rotation is too slow to drive the generator efficiently, so a gearbox converts the high-torque and low-speed mechanical energy of the main shaft into the…
Once the yaw ring is installed, the nacelle main frame must be turned over in order to complete the yaw system assembly. Temporary legs are installed, and fixtures are added to the yaw ring. The main frame is lifted, and one side is let down while the frame is rotated. Here you can see the…
The yaw ring assembly fits in a machined groove in the nacelle main frame casting. Several studs are inserted to locate the ring as it is lowered into the groove. The ring is lifted and carefully lowered into position. The remaining studs are inserted and run down. Spacers are added, then nuts are installed and…
Let’s take closer look at a typical sensor for a large wind turbine. The sensor mounts to the main frame; its gear is driven by the yaw ring. This sensor employs an incremental encoder that tracks nacelle position, along with a group of limit switches dedicated to cable twist control Here we can see the…
Let’s take a closer look at some of the sensors used in the yaw control system. Potentiometers,encoders and ultrasonic sensors may be used to detect wind direction. A potentiometer is a variable resistor consisting of a resistive strip, 3 terminals, and a movable wiper. The movable wind vane is connected to the wiper. As the…
A wind turbine is a sophisticated system of components that must all work together to efficientlyproduce power. Like most sophisticated systems, it can be divided into sections. Some sections are dedicated to capturing the wind energy. Other sections convert the mechanical kinetic energy into electrical energy. All of the sections depend on a control system…
Power from the yaw motors is transmitted to the yaw ring through a reduction gearbox which provides both speed reduction and torque multiplication. This yaw drive uses a planetary gearbox with the motor mounted vertically at the top. Planetary gearboxes are often used on commercial wind turbines because they offer high reduction ratios from a…
The main parts of the yaw brake hydraulic system and their functions are Accumulator: The accumulator stores fluid under pressure, and serves as a backup source of clamping pressure if system pressure is lost. Bleed Valve: Used to drain fluid from the accumulator to relieve pressure during service operations. Brake Calipers: Pressure in the brake…
The primary mechanical parts of the Yaw System are This section provides information about the relationship of the yaw bearing, yaw ring, and brakes. Yaw rings The yaw ring is a large gear that engages the pinion gears of the yaw motor gearboxes. Because these gears carry high loads, proper lubrication is important to prevent…
Video: Wind Turbine Yaw System Introduction The wind turbine yaw control system provides two functions that are crucial to safe and efficient operation: The nacelle must point directly into the wind for maximum efficiency. Also, a rotor disk that is not perpendicular to the relative wind experiences higher loading on the portion of the disk…
Why on earth do all wind turbines have exactly three blades? ship propellers can manage with two – and one would immediately think that 4 or 5 blades would catch even more wind and therefore provide even more power. The 3-blade horizontal axis wind turbine is the most advantageous option, in several technical and operational…
The blades of a wind turbine are affected by four forces: drag, lift, centrifugal, and gravitational forces. Drag Force on Wind Turbine Drag forces are caused by the air molecules that hit the surface of the blade facing the wind. A major component of the drag force acts in the direction that is parallel to…
In the 1970s oil crisis, many countries began to explore alternative energy options and their viability. In the US, NASA, and the Department of Energy have collaborated to develop a series of megawatt large research wind turbines known as Mod series. The Mod Series The wind turbines developed in the mod series were very expensive…
After the invention of electricity, in the late 19th century inventors turned their attention to generating electricity from the wind. Although windmills were there for a long period, they were mostly used for non-electric purposes. In this post, we will review the historic development of wind turbines from the 19th century to the 1960s. Blyth’s…
You will be surprised to know that the first known wind turbines recorded in history were Vertical axis wind turbines, not the current dominant technology of horizontal axis wind turbines. This dates back to the 7th century B.C when vertical axis windmills were built on the Persian land. They were based on the aerodynamic drag…
Wind turbines work on a simple principle. The wind hits the rotor blades. The combination of wind speed and blade rotation results in a pressure distribution on the rotor blades. The pressure distribution causes a turning moment (torque). The turning moment rotates the shaft. The shaft is coupled to a generator that produces electrical power…