A global supply chain is just the first step to building less costly, more reliable, and safer wind turbines.
Dave Schaetz, Industry Technical Consultant Alternative Energy Steve Ludwig, Safety Programs Manager, Rockwell Automationwww.rockwell.com
By leveraging panel building services from a global supplier, a turbine manufacturer gains standards-compliant, custom, control, and electrical distribution panels, such as the turbine control panel (above), while focusing time and internal resources on its core competencies.
Aggressive state-sponsored renewable portfolio standards are reducing the nation’s dependence on fossil fuel and driving expansion of the wind industry. Colorado and California, for example, are aiming for 30% of their energy to come from renewable energy sources, including wind power, by 2020. Seeing this growth potential, wind-turbine manufacturers around the world have their sights set on expanding U.S. operations.
Of course, there will be obstacles. Today’s challenges include establishing and managing an effective supply chain, identifying and complying with relevant standards, improving worker and equipment safety, and remaining competitive as customers demand shorter time-to-market cycles.
Another challenge is remaining competitive against other power sources. The Levelized Cost of Electricity (LCOE) is the total lifecycle cost to build and operate a plant over a period, divided by the total electricity produced by that plant. Wind-turbine manufacturers can use LCOE as a metric to compare the cost of generating power with wind. Continuously improving wind-turbine design and performance of wind turbines can help lower the cost of electricity they generate. For those expanding in the U.S. market, these six best practices can help build wind turbines more cost effectively.
Establish a global supply chain with regional experience
Wind-turbine manufacturers expanding operations in new markets may encounter several supply chain challenges including managing costs, inventory, and vendor relationships. Working with a reliable supply-chain partner that provides value-add services such as electrical engineering, design, and manufacturing, lets the OEM benefit from one local point of contact for supply-chain considerations. It also frees internal resources to focus on core competencies and lowers the total cost to design, develop, and deliver new turbines.
A global supplier with broad industry experience also can help the turbine manufacturer implement a successful production-management system based on industry best practices. The supplier can also help weather economic downturns and the boom-bust cycles detrimental to companies that only focus on one or two industries.
Turbine manufacturers partnering with a global supplier can leverage their worldwide manufacturing facilities, providing one point of contact for design, documentation management, global coordination of assembly, and consistent quality for wiring, assembly, and testing. Most importantly, a global supplier’s distributor network helps ensure product availability and support.
Finally, partnering with an outside vendor for supply-chain management lets a turbine manufacturer effectively increaseits production capacity without increasing its internal workforce, letting existing staff and resources remain focused on the company’s core expertise – designing the best turbine possible.
Outsource electrical control panels
Engineering a control panel is time-consuming and can have significant impact on system cost for turbine design and development. An alternative to building control panels in-house is for turbine OEMs to retain design and documentation responsibilities, but work with third-party panel builders to streamline the process. A drawback is that as business grows in new markets, working with multiple panel builders often results in having to increase engineering and supply-chain resources to coordinate and monitor multiple supply sources.
Logix-XT controllers and Allen-Bradley FLEX I/O-XT products from Rockwell Automation are conformally-coated and designed using hardened components suited for rugged environments, without the additional installation and energy costs associated with auxiliary heating and cooling systems.
A more efficient alternative is for turbine manufacturers to work with a single automation supplier that can design and build the entire panel – including all control and power components – and help standardize component selection and panel design across many locations worldwide. This single point of contact through design, prototyping, and ongoing deliveries can help a turbine manufacturer increase production capacity without increasing its internal workforce. This frees existing resources that would otherwise be needed for engineering, procurement, inventory management, testing, standards compliance and troubleshooting support.
A supplier with a testing and validation lab for environmental cycling and accelerated-life testing gives a turbine manufacturer the opportunity in the design phase to engineer the best possible control panel. This can lead to benefits such as reducing panel size, selecting components that generate less heat, or designing an integrated safety system to help provide safe access to panels during operation.
Design for high availability and reliability
Source: Rockwell Automation
It’s important to lower the operating and maintenance (O&M) costs during and after the warranty period. Using off-the-shelf components with long-life cycles and leveraging a large network of global support with access to spare parts can help reduce system downtime when problems occur.
Offshore turbines have special technical needs because the weather there can be more extreme than on land. Many turbine manufacturers supplying offshore equipment meet design challenges by engineering their own solutions. But these can be susceptible to moisture and contaminants, resulting in short circuits, and conductor and solder-joint erosion.
A better alternative is to invest in components intended for these extreme environments and include them as part of a complete control and information architecture, helping improve product longevity while reducing integration and installation costs. For example, components intended for extreme environments help reduce panel costs and the need for additional heating and cooling equipment, resulting in lower installation and maintenance costs. Extreme-environment products are often conformally coated to provide environmental and mechanical protection. This significantly extends the life of the printed circuits and electrical components.
Source: GL Guideline for the Certification of Wind Turbines, July 2010, Figures 2.1.4 “Required risk reduction through protection functions,”
Conduct a standards and safety audit
Protecting people is most important, but protecting the large capital investment of a wind turbine is a close second. A safety audit identifies potential hazards, a required safety control system integrity level, and helps guide the selection of the overall control architecture to achieve the optimum level of safety.
Safety challenges come from several sources. Hazardous weather, for one, requires stopping quickly and safely. Safety-system designers are challenged with a mix of high and low voltages, depending on their section of the turbine (tower, nacelle, or hub). There may be low voltages, high voltages, or a combination of each. The voltage dictates having the safeguards necessary to mitigate risks in each area of the turbine.
Although most technicians don’t work in operating turbines, they must be protected against rotating parts in the nacelle and hub. Hence, turbine designers may need to use physical guarding, or provide special access requirements. Other examples of effective safeguarding include employing a safe-speed monitoring relay to detect rotor over speed, vibration sensors, switches to allow opening control-cabinet doors, and medium-voltage switchgear for the lower portion of the tower to detect and suppress arc-flash hazards. Automation suppliers will continue to validate and test equipment to mitigate arc-flash hazards through new power-cabinet designs.
An Allen-Bradley GuardLogix PAC from Rockwell Automation incorporates standard and safety control in one controller.
Before designing the control system, a safety audit charts the course for an effective safety solution and evaluates risks early in development. This helps machine builders get their equipment to market in shorter periods. In addition, machine end-users profit from improved production thanks to automation that helps operate machinery and processes in a most efficient way.
Where hazards cannot be removed through design, machine builders typically install a fixed physical barrier that separates users from the hazard. When hazardous areas require frequent access, use nonfixed guards – those that swing, slide, or come off. Where non-fixed guards are impractical, use guarding devices that monitor the presence of the operator rather than the status of the gate.
Comply with regional electrical and safety standards
As manufacturers expand operations, they must adhere to local and regional standards. By following appropriate international standards, turbine manufacturers can globally streamline production processes, and gain access to customers around the world. As an added bonus, incorporating standards into the wind turbine design increases productivity and profitability for OEMs and wind farm operators.
Source: Rockwell Automation and GL Edition 2010
Recent standards are changing how designers approach wind-turbine projects with respect to safety. The standards include:
International Organization for Standardization (ISO) 13849-1/2 and International Electrotechnical Commission (IEC) 62061. These were recently mandated by the European Commission’s Machinery Directive, and issued in part to assist with the free movement of goods and services across a single European market. They are also considered among the most rigorous machine-safety standards in the world. Wind turbines fall under the scope of the Machinery Directive, and therefore wind turbines shipped into or out of Europe must comply with the appropriate standard now that EN 954-1 was withdrawn at the end of 2011.
These international standards add two important elements to the reliability of the machine’s safety function: time and risk. These two elements help machine builders take a more methodical approach to safety-system design.
Both international standards require turbine manufacturers to identify and document potential hazards associated with machine operation and the risk levels present to users. The safety system is then designed to the risk level associated with the hazards on the machine. Because appropriate documentation proves a machine’s level of safety, designers can better justify a needfor a safety-system upgrade, and operators can be more confident in the reliability of a machine’s safety system.
EMC (electromagnetic compatibility) management has emerged as a critical means of improving the reliability and operating life of electronic equipment employed in wind turbines. EMC directives are to ensure that all electrical devices in one electrical environment work properly and safely together. Specifically, EMC Directive (2004/108/EC) requires that an electromagnetic disturbance generated by any fixed installation not exceed the level above which radio and telecommunications equipment or other equipment cannot operate as intended. Under this directive, wind turbines are considered fixed installations, and therefore must be built according to the engineering practices outlined in the directive.
Other product directives have been issued in Europe in part to create a unified European market. Limited to “essential requirements,” which are general in nature and primarily focus on health protection, these directives are compulsory for products put into circulation and so apply to wind turbines and their sub-assemblies.
GL Guideline for the Certification of Wind Turbines (Edition 2010): The latest edition of this guideline makes references to the EN ISO 13849-1: 2006 Functional Safety Standard and requires that turbine manufacturers conduct a risk assessment to determine the maximum permitted probability of failure. Doing so helps justify an investment in new safety systems. Turbine manufacturers must follow ISO 13849-1: 2006 and IEC 60204-1 to gain GL certification of a turbine. GL publishes guidelines for certifying wind turbines.
Underwriters Laboratories, Inc. (UL) Standards: Large and small wind turbines are evaluated according to UL Subject 6140-1, UL’s “Outline of Investigation for Wind Turbine Generating Systems.” The systems are evaluated for risk of fire and shock including the electrical performance of safety-related control systems and utility-grid-interconnects for utility interactive models. While these standards apply in North America, they do not align directly with many of the European IEC standards, making it difficult for European turbine manufacturers to conform to standards when expanding to the U.S.
Certification (CE) Markings: Similar to UL Standards in North America, a CE marking says a product complies with European standards. A CE marking symbolizes that the equipment conforms to the applicable requirements imposed on the manufacturer. Turbine manufacturers must earn a CE marking on any turbine so it can be shipped throughout Europe.
Understanding the many, often complex, standards can be daunting. Turbine manufactures could meet the challenges by leveraging the expertise of certified safety consultants from a global supplier to navigate requirements and design an acceptable safety system.
Reduce complexity by combining turbine safety into controls
The evolution of safety standards and economic factors are driving the evolution of safety systems from hardwired to highly integrated configurations. Using an integrated platform for safety and standard control eliminates the need for electromechanical or hardwired controls. The more designers combine standard and safety control functions of a system, the better the opportunity to reduce equipment redundancies, improve productivity, and minimize costs.
Combining control functions also reduces the number of unique components in the turbine controls, which in turn reduces inventory costs. End users also benefit from less waste with fewer parts to maintain and replace throughout the turbine life cycle. In addition, integrated controls have broader intelligence regarding machine operation and status, reduce nuisance shutdowns and prolonged restarts, further improving machine efficiency and productivity.
Safety controllers provide integrated control and offer significant benefits in multistep shutdown or ramp-down sequences because they provide the necessary logic through software rather than the hard-wired logic of relays. An integrated safety controller is ideal for any application requiring advanced functions, such as zone control. Being able to monitor and control access to what is active on each level of the turbine is critical due to the size and distance between decks in a turbine tower.
Integrated safety systems also use a single programming software package. This can eliminate the need to write and coordinate multiple programs on different controllers, which in turn can simplify application programming and help reduce training and support costs.
Safe-speed controls provide a good example of effective control integration. With safe-speed control, safety input devices, such as guard-locking switches and emergency stop pushbuttons, connect directly to the speed-monitoring core of the control solution. This eliminates the need for a separate, dedicated safety controller. Extending use across multiple platforms, safe-speed controls reduce overall system cost and improve flexibility because they let operators perform maintenance and other tasks with a machine in motion. Safe-speed controls also help increase uptime and decrease energy costs because a machine need not be completely shut down and then restarted.
Networking offers another way to integrate safety and standard controls. The introduction of networks to industrial environments helps increase productivity, reduce wiring and installation, improve diagnostics, and ease access to facility data. Using an existing network to include safety information extends the same benefits, allowing seamless communication of the complete automation process on one standard network with one set of hardware and wiring. Diagnostics from smart devices that are networked together can also simplify designs and reduce integration costs.
On the horizon
Thanks to advancements in technology and the globalization of safety standards, turbine manufacturers can expand to new markets and help asset owners improve worker safety and protect equipment. By enlisting assistance from global suppliers, turbine manufacturers can expand smoothly into new markets and continue growing. WPE
Filed Under: Featured, News, Turbines
