A wind-turbine gearbox manufacturer has expanded its field-service portfolio to include the inspection and repair of the entire helical side of the gearbox up-tower. Moventas General Manager Steve Casey says its entire process can be performed in just three days, and the company (www.moventas.com) has successfully completed over 20 of these repairs to date.

Moventas says its on-site repair services can replace failing gears and bearings in about three days, and without need for a large boom crane.

“By using a mobile service unit and a small hydraulic crane, we eliminate the costs associated with mobilizing a large boom and secondary cranes normally required to bring a complete gearbox down from the nacelle,” he says. Shipping costs to and from the workshop are also eliminated.

A repair crew from Moventas has removed a gearbox top cover. Standard procedure says the crew is to inspect bearing and gear surfaces along with all interface components and connections.

A Moventas crew drives a self-contained mobile workshop to the wind-turbine site that contains all tools, components, and software required to repair the entire helical side of a gearbox. Each component, including the high-speed pinion and intermediate and low-speed gear assemblies, is lowered into the workshop where it is cleaned, inspected for damage and wear, and replaced as needed. In lieu of workshop-dynamometer testing, all up-tower helical repairs include condition monitoring using the company’s Condition Management System (CMaS). Casey says using CMaS ensures the same quality of repair as those performed in the company workshops. WPE

Windpower Engineering & Development

Even in the 21st century, wind forecasts of a few hours are difficult. The inscrutable nature of wind forecasting was highlighted in a recent study by AWS Truepower and Lawrence Livermore National Laboratory. Their project, Windsense, was focused on improving wind-power-generation forecasts by developing and applying analystical tools to identify the locations and variables to measure to get the greatest possible improvement in hours-ahead forecasts. The initial results from an application of this approach with the targeted placement of meteporological towers with wind sensors yielded only modest wind forecast improvements for one to two hours ahead. Researchers now think that combining observations at several targeted locations and using one or more sodar (sonar wind sensors) units to sense a larger volume of the atmosphere at each site might improve forecast by a more significant amount and for a few additional hours.

The test area for the forecasting research spans Washington and Oregon state and centers around the Klondike wind farm.

It is critical that wind forecasts are accurate, especially during ramp events, when energy from a regional aggregate of wind farms can change by more than 1,000 MW in an hour. The need for accurate alerts for these type of events is increasing as more wind energy flows onto the power grid. Ultimately, anticipating these types events an hour or two ahead will allow adding larger amunts of wind power to the grid.

Participant AWS Truepower (awstruepower.com) was to identify locations and sensor types required to improve short-term and extreme-event forecasts. The team used an Ensemble Sensitivity Analysis (ESA) technique to identify locations and variables.

ESA, an algorithm refined and applied by AWS Truepower, calculates a forecast’s sensitivity to input data (measurements) at a prior time and other locations. Mathematically, sensitivity is the amount of change in a forecast caused by a change in a measured meteorological variable at a prior time and another location. So ESA is a way to map forecast sensitivity and provide guidance on what and where to measure to most improve a forecast. The study has resulted in improved forecasting tools which alert control-room operators of wind conditions and energy forecasts during ramp events. The experiments in this wind project suggest that during certain weather conditions, mostly unexpected ramp events with precursors often inadequately sensed by existing observing systems, are often anticipated an hour or more in advance with a few specific weather variable measurements from key locations.

“This observation-targeting research conducted as part of Windsense has resulted in the development and testing of algorithms that provide guidance on what weather variables to measure and where to measure them to improve wind forecast performance,” said AWS Truepower Director of Forecasting John Zack.”These new software tools have potential to help forecasters and users make informed decisions that will enable them to maximize their investment in weather sensors.”

“We’re trying to forecast wind energy for any given time,” said project lead Chandrika Kamath at Lawrence Livermore National Laboratories (llnl.gov). ”One goal is to help people in control rooms at the utilities determine when ramp events may occur and how that will affect the power generation from a particular wind farm.” WPE

Windpower Engineering & Development

A Colorado-based company claims its axial gap, permanent magnet, direct-drive generator can produce the same torque with less than half the mass of comparably rated iron-core, direct-drive versions. The proprietary air-core stator, developed by Boulder Wind Power (boulderwindpower.com), contains no ferromagnetic material, so it eliminates all magnetic attraction between rotor and stator. This feature allows using lightweight, flexible, stator and rotor-support structures.

The BWP generator is constructed of multiple, identical segments. This modularity provides favorable logistics, such as low transportation costs, and lets crews make generator repairs up-tower. The simple ‘plug-and-play’ stator segments can be replaced by a standard two-man crew without a land-based crane.

Boulder Wind Power Product Manager Peter Smith says the design will be simpler, more efficient, and less costly to maintain than other wind-turbine generators. The firm aims to produce electricity at a significantly lower cost than existing equipment and competitive with fossil fuels. “We’ll provide our generator and controls to wind-turbine manufacturers for incorporation into their products, along with turbine design and engineering services.”

BWP says it has also developed design tools to prescribe a stator circuit etched on a printed circuit board. Automated printed circuit-board (PCB) manufacturing provides a design, manufacturing, and assembly simplicity unique to wind-turbines. Smith says a 3-MW generator is in test now at a site in Montana, but details are proprietary.

A problem with conventional multi-MW generators is that they are manufactured using low-volume production methods that depend on skilled labor. This introduces quality control issues. BWP VP of Engineering James Smith asks: “How precisely can they control the installation and assembly loads applied to the coils?

Installation involves hammering coils into the slots of an iron-core, then pulling them out axially through the slot in each direction to apply a tape to the end turns. What ensures that the insulation has not been damaged or disturbed in the process, or afterwards when coil ends are brazed? A tiny imperfection in the insulating tape can be the difference between a generator that lasts 30 years and one that fails after five.

The competitive landscape for direct-drive generators illustrates the torque density of the BWP drivetrain, a 50% improvement over the best-in-class PMDD versions. Torque density is based on torque-per-mass rather than torque-per-volume because the developer believes it represents a more relevant figure of merit and more closely aligns with drivetrain costs. Source: Boulder Wind Power

In contrast, James Smith adds, the BWP stator is manufactured using mature and repeatable PCB operations perfected by the electronics industry over the past 50 years. These advanced processes support the BWP insulation and conductor uniformly over the entire conductor surface. End-turn areas are encapsulated and supported in the same manner as working area conductors. BWP says this is superior to conventional construction.

James Smith also says the design eliminates iron losses associated with flux reversals in the stator. “Stator losses are limited primarily to conductive losses (I²R). The design minimizes eddy-current losses and eliminates hysteretic losses associated with all iron-core generators.” The high-torque density avoids torque limitations that constrain iron-core machines and allows large rotor diameters that deliver more than 30% more power than comparabe systems in low-wind speeds.

A comparison highlights the partial-load efficiency of the air-core PM generator to a modern direct drive (DD), iron-core PM machine and a DD wound-field synchronous machine. The BWP air-core machine hits efficiencies over 96% at rated power. A state-of-the-art, iron-core PMDD machine might reach 95% at rated power, while a representative DD, wound field-synchronous machine might be 93.5% efficient at rated power6 to account for rotor excitation losses. Although each design could theoretically exceed these efficiencies, their economics in multiMW, low-speed applications are unfavorable because the incremental financial benefits generally do not justify the additional costs for higher efficiencies. Source: Boulder Wind Power

The BWP generator is constructed of multiple, identical segments, modularity that provides favorable logistics and lets crews make generator repairs up-tower. “The simple ‘plug-and-play’ stator segments can be replaced by a standard two-man crew without a land-based crane,” says Peter Smith.

The U.S. DoE selected the company for a grant under the DoE’s Wind Power Next Generation Drivetrain Development program. It provides up to $700,000 of funding in the first phase, during which the company will develop a design and test program for a 6 MW, offshore wind turbine. The company will also validate the scalability, feasibility, and economic advantages of its patented technology in a 10-MW offshore wind turbine. WPE

Windpower Engineering & Development

It's beautiful but is the wind farm running a peak efficiency? WindManager, say its developers, can make that happen. It is a turbine-independent system based on latest international standards such as IEC 61400-25 and RDS-PP. It's also scalable from a single wind farm to large multisites.

Renewable-energy consultancy Natural Power announced the release of WindManager – a wind-farm portfolio, information system that increases profitability of wind farm operations.
WindManager is a turbine-independent system based on latest international standards such as IEC 61400-25 and RDS-PP. The system is scalable from a single wind farm to large multisite wind farms. The system captures real-time data, presenting availability, losses, and key performance while supplying tools for analysis, effective work processes, and fact based decisions. All processes are in place to increase profitability of wind farm operations.

The software comes with four modules for effective wind farm operations:

• Monitoring connects all turbines to a central system so all data is stored and visualised in a map view. Trends can be monitored and preconfigured reports summarize performance and energy production against targets.
• Analysis features let wind farm personnel perform stop analysis, loss analysis, and understand all downtime issues as they arise
• Operations Management provides daily or weekly work scheduling, resourcing, and collaboration across teams.
• Access to the system API, data-management tools, and tools for extracting performance data to MatLab allows performing further research and analysis in house

The screen shot from WindManager shows the locations of several turbines on a peninsula along with charts and graphs that tell of their performance.

WindManager comes brought to the U.S. wind-energy market by Natural Power in collaboration with Operations Management Software provider, Baze Technology, which has a track record of deploying the system for wind power as well as other industries.

the developer offers the software with its existing suite of wind farm management tools including WindCentre, a 24/7 operations control room which uses Natural Power’s Melogale data analysis platform, ForeSite for wind farm energy forecasting, and SeaPlanner for offshore GIS, site, and data management.

Scott Mackenzie, Asset Management Director at Natural Power commented: “WindManager has been successfully operating in the UK and Europe for over a year now, so we are very pleased to be extending these services to the US market.

“This product helps wind farm owners and operators experience a real time view of their assets, with customers benefitting from a range of additional tools from energy forecasting to independent operational site control,” says Natural Power Asset Management Director Scott Mackenzie.

Natural Power
www.naturalpower.com

Windpower Engineering & Development

To meet the needs of the global economy and increasing domestic demands, Lee Spring is introducing new metric product lines and expanding existing metric-stock products.

The company has expanded its existing metric compression and extension products with springs that meet the physical parameters of the European Compression Standard (DIN 2098) and the European Extension Standard (DIN 2097).  These additions are available in either zinc plated music wire or passivated 302/304 stainless steel, with the exception of compression wire sizes from 0.10 mm to 0.40 mm, which are only available in stainless.

As assemblies continue to get smaller, so does the requirement for products that work within reduced spatial parameters. Lee Spring has added over 100 new REDUX Wave Spring Inch Stock designs and has more than doubled its Belleville Washer offering. Generally, Wave Springs occupy 30 to 50% of the compresses height space of comparable round wire springs, offering equal deflection with the same load specifications. Belleville washers are designed to support high loads with relatively small deflections and solid heights. The online catalog, available at www.leespring.com, features user friendly product search engines as well as ecommerce options.

Lee Spring Co.
www.leespring.com

Windpower Engineering & Development

The first Nordex N117 nacelle is going up.

Turbine manufacturer Nordex says it has passed a major milestone towards the series production of the N117/2400 onshore turbine:  On 16 December 2011, it installed the first version of this model at the “Stadum” citizens’ wind farm in Schleswig-Holstein. With a 117-m rotor diameter and a 10,715 m² rotor sweep, the N117/2400 is the most efficient IEC-3 turbine in its class, according to the manufacturer.

The primary new feature is the rotor blade, which is 8.5-m longer than the previous onshore model. In typical IEC-3 locations, the N117 turbine achieves a capacity of over 3,500 full-load hours, exceeding other turbines in this category by 20%. This translates into a capacity factor of 40%. As a result, N117/2400 owners can have high and steady electricity production in regions characterised by lighter winds. With a length of 58.5m, this is Nordex’s first blade to be made from carbon fibre, a material lighter yet more rigid than glass-fibre hybrids. Despite its greater length, the NR58.5 blade weighs less than 11 tons and is thus somewhat lighter than its predecessor.

The N117 rotor spans 117 m.

Nordex unveiled the N117/2400 at the 2011 EWEA in Brussels. Installation of the first turbine was completed on schedule. Consequently, Nordex completed static testing of the N117/2400 rotor blade at its own blade production plant at its Rostock facility. Static testing involved pulling the blade consecutively in four different directions; the forces applied exceeded those arising in the field by many multiples. The successful test was a prerequisite for the award of the TÜV Nord design certificate. Full certification of the new rotor blade requires static and dynamic testing. This entails fatigue testing during which the blade is vibrated for about six months to simulate exposure to such forces over the entire life cycle of the rotor blade. Dynamic testing follows. Both tests are key prerequisites for the award of the type certificate and commencement of series production by Nordex from mid-2012.   

The Nordex product range includes one of the largest series wind power systems in the world (N80/2500, N90/2500, N100/2500, N117/2400) with more than 1,700 of these turbines having been produced to date.

The estimated calculated annual energy yield of the N117 at the 91-m hub height is about 9.9 GWh for the Stadum site, which has a mean annual wind speed of 7.4 m/s. Together with two N100/2500 plants at the same site, the wind project produces a total annual output of 27 GWh.

Nordex
nordex-online.com

Windpower Engineering & Development

Orange circles identify countries and regions negatively affected by the unrest in the Middle East. Blue circles identify countries and regions less likely to do business in the region. The figures and diameters are average percent of businesses responding positively to the survey proposal.

Unrest in the Middle East and North Africa, and its impact on oil prices, 44% of global businesses would now support increased government investment in renewable and alternative energy, according to the latest research from Grant Thornton’s International Business Report (IBR). In the U.S., 41% are more likely to support increased government investment.

 With the economic situation becoming more uncertain as the year progresses, the price of oil has generally reflected global concerns. Brent Crude, oil which started the year at $85 a barrel, climbed to $125 a barrel in April and has generally remained above $100 a barrel since.

 Many businesses would be willing to endure the short-term pain such investment might create: 51% of the global respondents said they would accept higher energy costs in the short-term to reduce their economy’s reliance on oil and have more stable prices in the longer-term. However, while this stance was supported by 60% of businesses in North America and the U.S. and 53% in the G7, just 35% of those in the Brazil, Russia, India, and China economies agreed.

 “The Arab Spring is a key event in global energy security. The region holds substantial known global oil reserves, so a dramatic increase in the price of oil was to be expected,” says Cal Hackeman, global leader of Grant Thornton’s Cleantech industry group and the U.S. Technology industry managing partner.

“However, this seems to have sharpened the minds of businesses to the challenge of moving towards more sustainable sources of energy,” added Hackeman. “At a time when the global recovery remains fragile, it is encouraging to see that many businesses would support extra investment in renewables even if this caused energy costs to rise in the short-term. These results should serve as a reminder to governments and international organisations that reliance of economies on oil needs to be addressed.”
Grant Thornton International Ltd.
Gti.org

Windpower Engineering & Development

The market for electric industrial vehicles is already large. For example, by law, forklifts must be electric when used indoors. Little growth remains in that market, but outdoors, most all earthmoving and lifting vehicles use conventional internal-combustion engine.

That is about to change because hybrid-electric versions reduce cost of ownership and exposure to price hikes with fossil fuels. Airports, often government owned or funded, are under great pressure to finish converting their Ground Support Equipment (partly using federal grants) to pure electric versions for on and off the tarmac.
IDTechEx
www.Idtechex.com

Windpower Engineering & Development

A range of standard shapes for the light pipes are available as well as customized versions.

A designer and manufacturer of optoelectronics now offers waterproof light pipes. The LED light pipes, which meet IP68 specifications, come in a wide range of options and can be built into a wide range of ruggedized, outdoor, shipboard, and other applications. They are said to work well where there may be humidity or condensation, rainfall or snow melt, or direct exposure to water.

A range of standard shapes for the light pipes are available as well as customized versions. This includes different launch surface options and colors available upon request. Standard lengths vary from 4.5 to 100mm. The ambient temperature ranges for the guides are -20 to +50°C.

Elma Electronic Inc
www.elma.com

Windpower Engineering & Development

The RT3 tethering systems let instruments swiftly detach from the retractor when necessary.

Accidentally dropping or misplacing an expensive hand-held instrument or tool, particularly when working aloft, is a costly and potentially dangerous event that can be avoided. Aside from the inconvenience and lost down time spent retrieving or searching for the dropped object, delicate instruments such as bar-code readers and gas detectors can be damaged beyond repair. Gear Keeper’s RT3 series of instrument and tool lanyards offer exceptional benefits of safety, productivity, and comfort for workers. When the instrument is stored, held or used with a Gear Keeper RT3 retractable tether, the dangers of entanglement, fatigue and annoyance are minimized and worker satisfaction and output are maximized.

The RT3 Gear Keeper instrument tethers are says to operate in even the most volatile environments. The retractable tether mounts securely to the wearer’s belt, providing a low-profile tethering system that avoids snags and snaps back. The teather features a 360° rotating clamp-on belt clip and a dual-axis rotation option with 180° of swing-away from the body.

Gear Keeper’s spring loaded, self-retracting RT3 security system prevents loss or damage of critical gear. If an instrument is dropped, the tether easily absorbs the stress these heavier instruments produce. When the instrument or tool is being used, pull it out… use it and when you’re finished let it go… it automatically retracts back.

The tethers come with a comfortable reach of 42 in.of extension. Its sturdy Nylon/Kevlar cable features 80 lb. break strength for heavy-duty industrial use with maximum breakage strength and durability.

The instrument tethering system can take the punishment many industrial applications demand. The retractable tethers are intended to survive extended salt water and chlorine exposure. They are almost jam-free with a patented flushing system that self clears sand and other debris from the retractor mechanism. With more than one million systems in use, the devices have a failure rate of less than 0.001%. The full line of Gear Keeper instrument tethers and accessories are available on the company’s website.

Hammerhead Industries
www.gearkeeper.com

Windpower Engineering & Development