So what should be monitored as the inspection approaches, and what is the best method for effective condition monitoring? Consider a few options for a typical MW-class wind turbine.

Main bearing

The repair of the main bearing typically involves removing the hub. With vibration analysis condition monitoring, the lead times to bearing failure are often quite long, on the order of several months. This is largely in part due to the slow speed and intermittent operation. Grease analysis is one method to determine the condition of the bearing. Other conditions (such as imbalance for example) cannot be detected with grease analysis. So with arguably one of the most expensive repairs on a turbine, end-of-warranty inspection must be addressed.

According to those who have performed end-of-warranty inspections, grease analysis gets mixed results. The main-bearing temperature from SCADA sweeps might be helpful but it is hard to determine the severity of damage from such data. Hence, main bearings must be examined in an end-of-warranty inspection.

Gearbox

The accompanying table (next page) shows common inspection techniques for a turbine gearbox. There is a significant difference between which worn components can be detected with a bore scope and a vibration-analysis inspection. A bore scope doesn’t address the main bearing, generator, or correctible conditions such as misalignment, imbalance, looseness, generator lubrication, and electrical shorting. Despite these gaps in detection, it is still considered the standard practice for end-of-warranty inspections.

Repairs in the planetary section and low-speed shaft (LSS) usually require a crane call-out. Repairs in intermediate and high-speed shafts (HSS) of some models can be performed up-tower for a fraction of the downtime and crane cost. Oil analysis also can help, especially when the testing looks for a proper moisture content, total acid number, viscosity, and particle counts.

“You get a full picture of the condition of a drivetrain using a bore scope and vibration together,” says Upwind Solutions Director of Quality Control Russell Leach. “They complement each other to give a 360 degree view of the gearbox health.”

Generators

Not much is done on a generator in typical end-of-warranty inspections. Hence, it’s a good idea to use vibration analysis on it. “Vibration analysis makes detecting major failure modes in the generator a piece of cake,” says Don Roberts of B9 energy. “Resistance testing usually requires manufacturers’ approval beforehand.” Common generator issues (electrical shorts and bearing failures) were detailed in a previous condition-monitoring article on generator condition monitoring (Windpower Engineering & Development, November, 2011).

The best methods for ensuring that a turbine will enter post warranty in optimal condition are those that give the manufacturer and owner a clear and thorough picture of the turbine’s condition. “The renewable energy or production tax credit is paid when the turbines are reliable and productive,” says Roberts. “To ensure reliability, install a permanent condition-monitoring system within 12 to18 months prior to the end of warranty. This enables “alarming,” and a sufficient data stream to support claims and maximize the value of a condition-based monitoring system,” adds Roberts. WPE

By: David Clark/Condition Monitoring Consultant

Windpower Engineering & Development

Wind farm operating costs as supplied by a US asset owner.

“Our system borrows technology from the aerospace industry to diagnose early-stage wear —months in advance of a fault—and then to accurately estimate the remaining useful life of each component,” said Eric Bechhoefer, chief engineer at NRG Systems. “We also eliminate the need for a diagnostic engineer by integrating data into a single, readily understandable health indicator for each component. The data can be read and acted upon by anyone.”

A new gearbox goes in because sometimes, SCADA is not enough. NRG Systems is finished beta installation of a TurbinePhD system and expects to release the product summer 2012. The system holds U.S. patent number 8082115.

Condition-monitoring systems use sensors to detect component faults, letting maintenance professionals avoid equipment failure. TurbinePhD uses digital signal processing techniques to detect component wear before it escalates into a fault. Smart sensors with embedded processors use algorithms to diagnose problems and then transmit that data to a secure website, where maintenance professionals can see easily-understood turbine health indicators for each component and drill down to view supporting data.

NRG Systems
http://turbinephd.nrgsystems.com/

Windpower Engineering & Development

The show was hosted by a London-based company. I find there’s just something about the British accent that adds an extra air of pleasantery during the registration and moderation. A representative from Make Consulting started things off by touching on a hot topic: the extension of the PTC. The company says it expects the credit to be renewed, probably for another year, after the November elections. This is an opinion I also heard at the ABB event earlier this week. I have to say it makes sense, as it’s a shame clean energy has become an area of political division when what it really needs is bipartisan support. But I suppose, in this political climate, we should be thankful just to have it renewed in the nick of time.

Make Consulting also noted that many of the turbines online today are becoming outdated. Even 5-years-old models are starting to be considered old-fashioned and could benefit from upgrades or repair—though it’s hard to know how much value doing so holds for availability, and financing isn’t easy.

All about predictive maintenance
Stuart Cameron from Romax Technology discussed a point I’ve heard often lately in the wind industry. He encourages the shift from reactive to predictive maintenance. Out of reactive, preventive, and predictive maintenance, predictive offers the best balance of failure and maintenance costs. Cameron says predictive maintenance offers up to 50% cost reduction over reactive maintenance. This is especially helpful with turbine drivetrains and gearboxes because the industry is seeing an increasing failure rate in these components. Moventas agrees, stressing condition monitoring and understanding what went wrong the to help prevent problems. The representatives also noted that performing maintenance tasks together as much as possible is important to saving time and money.

A bit on blades
The same is true for blade maintenance. Getting up-tower is time consuming and costly, so it makes sense to performance as much maintenance as possible while you’re up there. Wind Energy Solutions (WES) gave a great presentation on blade predicaments and encourages predictive maintenance as well. The company representative recommends starting a database on blades at the end of the warranty and deciding when to do maintenance ahead of time (probably during the non-productive season). He also suggests keeping to a periodic maintenance schedule. For blades, things to check for include rotor and aerodynamic imbalance, which are often due to installing blades at incorrect angles. He says the biggest aging issue with wind blades is leading-edge erosion. The problem can be fixed little by little with protective tapes or coatings.

WES says scheduled maintenance makes common sense because it increases availability, reduces large repairs by focusing on fixing smaller ones first, reduces crane and mobilization cost, and increases aerodynamic efficiency. However, due to lack of data to support cost savings, the WES representative says he has a hard time convincing operators that this is the way to go. The second biggest problem is lightning damage, which can be rectified through lightning-system testing. There are also problems with icing, but without any effective solutions. “If I had the solution, I’d be making some big money,” as he puts it.

There were many other informative sessions including some on improving gearbox reliability, collecting data to improve availability and more. I’d say the conference was definitely worthwhile, and so was my trip to Dallas. But now it’s back to Cleveland for me. After a week away, I’ve learned a lot. But I think I’ve had enough of hotel rooms for awhile.

Windpower Engineering & Development

These renewable energy tradeshows and seminars have helped, making my way to California, Texas and other states for the first time. But I was especially excited to make my way to New York for the AWEA Wind Financing and Investment Seminar. Somehow going to this world-renown city makes me feel like a real American.

What I didn’t expect was to experience the hustle and bustle so early in my travels. The turbulence and sharp turns on my flight had me holding on tight and praying profusely. But once we found some smooth air, I relaxed enough to enjoy my first view of the city. Even over the shoulder of the girl with the window seat (I had offered her my aisle, which she kindly declined and proceeded to utilize her aerial view by napping the entire way!) my first view of Central Park was amazing—the skyline, breathtaking.

Unfortunately, my tumultuous journey soon resumed as I was crammed into a shuttle bus with 10 other people and driven around on an hour and a half journey of hotel drop-offs. Once again, I viewed the streets of the city I so longed to see behind heads and next to a woman with a frequent cough (my germaphobic self’s worse nightmare). Thankfully, once a few passagers cleared out I moved up front to witness the ride from a more pleasant perspective. The driving and traffic was just as congested as I expected, though not as fierce as I’ve seen in Florence (but these cars and trucks are larger). But the big-city annoyance and angry honking I expected was not so much. In fact, some idiot tried to squeeze through a narrow ally between our van and a parked car (with literally centimeters to spare) and our driver actually helped direct him.

In the end, I finally made it to the grand Crown Plaza near Times Square (another site that made me smile with excitement). There, I quenched my parched throat with fresh water from the tables as as I listened to several intriguing presentations.

Elizabeth Salerno, chief economist and director of industry and data analysis at AWEA, started things off by discussing AWEA’s 2011 Market Report. According the the report, the U.S. wind industry installed 6,816 MW in 2011, 31% higher than 2010, for a total of 46,916 MW installed to date. Wind capacity has increased with an average annual growth of 35% year-over-year over the past five years. Wind capacity captured 31% of new power plant construction in 2011 and natural gas 42%. Still, seeing this kind of significant progress is quite encouraging and the industry should be proud.

One discussion that particularly interested me was how strengthening project performance can drive and support investment. Mark Bolinger, a research scientist at Lawrence Berkeley National Laboratory noted how taller towers, larger rotors and other technical improvements have boosted capacity factory for more energy yield. He stresses the importance of keeping performace high as projects age. Robert Poore, VP of business and service development at DNV Kema said better resource asessments can also boost project performance. He says to ensure quality assessments, one must be aware of considerations in wake modeling, atmospheric conditions, long-term corellations and availability. Greg Tkvorian, senior project manager at SAIC Energy, focused on best O&M practices for keeping wind production high. He stresses having technicians onsite who are knowledgable and trained, using 24-7 monitoring (especially condition monitoring), ensuring spare parts abailability and applying new advancements. “Routine, Preventive, Predictive Maintenance!” was his mantra. According to Tkvorian, about 50% of maintenance costs on an average wind farm are unplanned. O&M crews should strive to change this, putting emphasis on planned, predictive work.  Timothy Fratta, business and service development manager at enXco, had some interesting things to say about the economics of O&M, noting it comes down to risk tolerance and where yours is at. He says service provider fees and major component reserves are the greatest O&M costs on an average wind farm (sidenote, an average oil change on a 100-MW project with 2-MW turbines costs $250,000! Good thing you only have to do this every 5 years. Makes me feel better about the $30 I shell out for my car). He says it’s important to consider unknowns, such as long-term trends, regulations and corporate consolidates or changes (on one site he had to deal with a lack of an OEM).

A discussion on securing grid access was also interesting, as Marc Spitzer, a partner with Steptoe & Johnson and a former FERC Comissioner made an interesting point. He says while there is much discent between parties when it comes to renewable legislation, FERC orders have been bipartisan decisions. He hopes one day the same will be true for renewables. Spitzer says a big challenge in this area is cost allocation, hence FERC Order 1000. He urges the industry to weigh in on where to site power lines. A representative from Iberdrola also made a good point. He says the best U.S. wind resources are located in areas where the grid is the weakest. The nation has had success with constructing interstate pipelines for natural gas and now we need to do the same in transmission to create a strong backbone for projects. Lastly, Gary Moland, director of market analysis with GL Garrad Hassan, discussed problems with curtailment and congestion. Curtailment occurs when wind plants must reduce their generation output due to congestion on a transmission grid with inadequate capacity. He says curtailment studies can help quantify risk on a regional and local level.

With that I leave New York having a better idea of issues and trends in wind finance, and an understanding of why so many people from around the world have eagerly come here. I can now say I’m one of them.

Windpower Engineering & Development

SmartSignal identifies most all major equipment failures on all critical rotating and non-rotating equipment across all OEMs. When Shield 4.0 spots a problem, the developer says it sends a notification to people who need to know—with a brief problem summary, key tags, and values. Multiple alerts are combined into one diagnostic notification, which narrow s the range of potential problems and reports urgency.

Proficy SmartSignal Shield 4.0, software for wind power and other industries, helps large equipment operators detect equipment problems early and avoid surprise equipment failure, thereby increasing productivity while minimizing costs.

The software provides early warning of impending equipment problems, diagnostic guidance, and prioritized actionable intelligence. The software is said to let users move from reactive to proactive maintenance by working on the equipment that needs attention, and on the most critical problems first. They can focus their efforts on action, not analysis—increasing reliability, availability, efficiency, and compliance.

Shield 4.0 was developed based on shared blind data from GE customers—the world’s largest base of predictive-diagnostic intelligence. From experience based on millions of machine hours and tens of thousands of failures from over 12,000 rotating and non-rotating assets, GE was able to identify fault patterns, in context of operating behavior, that are critical to the Power and Oil & Gas industries, and incorporate them into the software.

The software’s diagnostic algorithms combine observations on multiple individual sensors to pinpoint failure effects. Beyond vibration and thermal analyses, the solution models all data on all critical rotating and non-rotating equipment. The software monitors equipment 24 hours/day, letting users organize maintenance projects with confidence. Shield 4.0 allows clear access to diagnostics and rules, so users can understand and adjust the software based on their own expertise.

SmartSignal
www.ge-ip.com/smartsignal

Windpower Engineering & Development

The OPC Foundation established the OPC Certification program to help vendors verify that their products meet end-user requirements of plug-and-play interoperability, reliable behavior and meet inimum performance expectations by providing well-defined behavior, documentation and Test Tools for the testing of OPC Servers and Clients.

TopView
www.exile.com

Windpower Engineering & Development

Titan Tool Supply, Inc.

www.titantoolsupply.com

Windpower Engineering & Development

Sensors that monitor temperatures, pressures, vibrations, and more are one part of a condition-monitoring equation. Software to make sense of the signals is the other half. The software should install easily and then let users configure it for real-time monitoring, event detection, notification, logging, reporting, and presentation of measurement data and the abnormal condition events. This task may be simplified if the data and monitoring software support vendor-neutral protocols and interfaces such as OPC and SQL.

Condition monitoring software should be able to read the data, aggregate the data, and take action on it, action such as:

Capabilities in the condition monitoring software TopView lets users set alarms, notify appropriate personnel when necessary, send data and alarm reports to remote locations, and do so using any of several transmission methods.

Current measurement and aggregate data monitoring. This capability requires detecting abnormal events defined by the behavior of data, while the required data may extend beyond the current measurements provided directly from instrumentation. Conditions may be defined by aggregated measurement values as well as aggregated event activity (e.g. event or alarm flooding – a high frequency of alarm activity).

Current measurement condition monitoring defects is the ability to monitor and recognize abnormal conditions of the current measurement values.

Aggregate-data condition monitoring determines abnormal conditions through the analysis of multiple values. The multiple values may be previously scanned values of a single measurement (recent history aggregate), or current values from multiple measurements.

Single-measurement aggregates provide calculated results using recent history of a single measurement. For example, vibration data can have wide swings of current value measurements. For example, TopView lets the user monitor calculated results such as “five-minute average” or “10 minute standard deviation” by caching recent history and calculating the desired aggregate value.

Multiple measurement aggregates are calculated on the current value of multiple measurements. These aggregates maintenance teams monitor data such as summations of multiple measurements and differences between measurements. For example, monitor the total load of five turbines or the load difference between two turbines.

Aggregate-event activity summarizes current and recent event activity as data values that can be monitored for abnormal behavior. These event statistics can be used to recognize higher-level events such as “more than five turbines currently have abnormal vibration measurements” or “there have been more than 10 temperature alarms in the last hour.” Such situations may be difficult to recognize without the proper condition monitoring tools, yet they provide significant value by monitoring overall health of the condition monitoring system.

O&M personnel can reveive operations data and alarm reports on their smart phones. If they don’t respond to receipt of the message, and if so programmed, alarm notices can be then sent to additional personnel.

Recognizing abnormal conditions

Once measurements and aggregates are available for monitoring, users can instruct the software to recognize abnormal conditions. These events may signal a current alarm condition, or warnings of potential alarms if the condition worsens. In addition to recognizing unexpected values of monitored data (greater than or equal to…) the conditions may include delays (exists for a period of time), deadbands, and blackout periods.

Examples of abnormal conditions: temperature above threshold for 2 minutes, power output too low for speed, acoustic volume too high for 5 minutes, and 5-minute average vibration trending up for one hour.

Log and notify
Once abnormal conditions (“alarms”) are recognized, they are logged and optionally sent as notification messages to ensure that the appropriate personnel are aware of them. Notifications can be sent through email, SMS/text messages, pagers, and phones. What’s more, if recipients do not acknowledge receipt of the notification, the message can be escalated to additional personnel to ensure that it is eventually received.

In addition to notification at the time of the event, the software provides multiple views of the monitored data and events.

A client application provides real-time displays of current values and alarms, audible signals of abnormal events, browsing of event history, and tools for performing event analysis (frequent alarm points or alarm flooding).

Alarm reports (event summaries over time) can be generated interactively or scheduled and emailed. Web-friendly HTML displays of current values and alarms can be stored, viewed, and published. RSS feeds of events allow combining event data into mobile devices and web pages.

Having the tools to successfully monitor abnormal wind turbine conditions, notify the appropriate personnel, and empower them to respond accordingly, can save a tremendous amount of time and money. TopView’s breadth of features and ease of use provides a powerful and versatile do-it-yourself solution that has been proven successful across many industries including multiple wind farms. WPE

By: Dane Overfield/Software Product Development Lead, Exele Information Systems Inc., www.exele.com

Windpower Engineering & Development

The Condition Monitoring System Ohm-Guard, from Bachmann electronic, lets most anyone view data from the monitored plant over the web.

Bachmann is increasing the efficiency of condition monitoring by integrating it into plant control. Condition-monitoring systems (CMS) allow increasing the availability and efficiency of wind turbines. Bachmann Monitoring combines signals from CMS-sensor unit with the operating status, leading to better diagnostic accuracy and increased CMS efficiency.

Condition monitoring already benefits operators at wind energy plants. Detecting faults early on monitored components prevents major damage and lengthy unscheduled downtimes that often involve considerable costs. The quality of the maintenance improves, thereby having a positive effect on the lifespan of the systems. What’s more, insurance companies usually reward CMS-equipped installations with lower premiums.

The benefits can be increase even more through the holistic integration of plant controls and CMS. However, to achieve real synergies, data collected by the CMS must be available to the automation system and vice versa, without need for interfaces. The Bachmann CMS W-Guard and AIC212 CMS module, for example, can integrate without difficulty into Bachmann electronic’s comprehensive M1 automation family. Thus more reliable statements are possible and that improves CMS efficiency.

Bachmann electronic GmbH
www.bachmann.info

Windpower Engineering & Development

CBMvisionMD is a cost-effective online, wireless, condition-based monitor that installs easily to periodically monitor and diagnose assets. It can archive and deliver near real-time diagnostics and detailed machine condition data globally using cloud computing and the developer’s CBMvision Explorer Software.

CBMvisionMD is a mobile diagnostic system that lets users monitor rotating machinery on an on-going basis. The system can collect data for hours, days, or months, as necessary to collect the required data and can be easily moved to another machine or site when the task is complete. Cloud-based technology ensures the data is available anywhere in the world in near real time.

CBMvisionMD is built on the philosophy of easy installation, rapid configuration, and clear diagnostics, and is intended for remote applications, such as wind turbines, pumping stations, offshore platforms, or for collecting additional data on-site when a hand-held device will not suffice. 3G/4G cellular communication technology makes data transfer easy and secure. The right information gets to the right people, at the right time, anywhere in the world.

 CBM Enterprise Solutions LLC
Cbmenterprise.com

Windpower Engineering & Development