SCADA and Condition Monitoring Rely on Robust Network Switches

Aug. 19, 2010
In today’s world of electric energy generation, transmission and distribution, the data communications and information technology (IT) infrastructure plays a key role in enabling the implementation of networked systems that can help maximize power output, better manage capacity and increase safety, while reducing costs and waste.
The rapidly expanding wind energy sector is no exception. This article examines the role that Supervisory Control and Data Acquisition (SCADA) systems and remote condition monitoring play in helping wind energy farms achieve these objectives.  It will also discuss why it is essential to select environmentally hardened network switches and hardware to achieve optimal SCADA performance and reliability in this harsh and demanding environment. Network connectivity means a smarter gridWith wind power representing one of the fastest growing and most promising sources of clean electric energy around the world today, companies around the globe are seeking more efficient and affordable ways to grow and secure their energy infrastructure while reducing costs and carbon emissions. There’s no denying that today’s quest for a smarter grid has its challenges.  To be profitable, wind farm owners and operators need to get maximum efficiency out of their turbines without encountering unplanned downtime due to equipment failure.  Turbine downtime is prohibitively costly and unexpected failure can lead to catastrophic results.  One key part of the solution is to build a remote monitoring and control information and communications infrastructure.  Just as industrial network connectivity, automation and control have proven effective in manufacturing and processing plants, so too can they help wind energy plants maximize output, avoid the likelihood of equipment failure, and increase safety for technicians responsible for maintaining wind farm sites.A ruggedized data communications network with remote connectivity ensures that operators will be able to access necessary information from a distant location to monitor the condition and operation of each piece of equipment.  This kind of 24/7 electronic vigilance reduces the risk that extreme cold, dust, vibration, humidity or other harsh environmental conditions will endanger the wind farm’s electrical system – or the Ethernet switches, cables and connectors that support mission-critical communication flow.SCADA provides integrated and centralized controlThe beauty of running a windfarm is that wind is free. This does not mean, however, that wind farm operations can afford to run inefficiently. Rather, because of the competitive nature of energy prices, owners and operators must strive to maximize productivity and ensure they are getting the most out of each turbine. Many modern day wind farms elect to implement Supervisory Control and Data Acquisition systems, which act as the central nerve center of the operation. The SCADA system is the key to linking the turbines, substations and meteorological equipment through an information and data communication network that gathers, aggregates, analyzes and reports on equipment performance and operational status.     Within the turbine tower, the SCADA system works by connecting sensors to the network.  The sensors, which record wind speed, wind direction and shaft rotation speed, are connected to a PLC within the turbine nacelle.  The PLC, in turn, transfers data through the local area network (LAN) and back through the SCADA system, which acts as the central control center.  This feedback loop allows the operator to remotely control turbine pitch and yaw systems, if necessary, to ensure that the motorized blade and nacelle positioning mechanisms are in the right wind-oriented position to optimize air flow for maximum power generation. The SCADA system also records energy output and turbine availability, and can communicate an alert if an error should occur.At the substation level, the SCADA system also acts:•    to implement any requirements in the connection agreement to control reactive power production;•    to contribute to network voltage or frequency control; or, •    to limit power in response to instructions from the network operator.A Remote Terminal Unit (RTU) at each collector substation monitors transformer temperatures and tap positions, as well as alarm and status contacts on substation equipment.  Through the broad capabilities of the SCADA system, engineers and/or technicians can detect inefficiencies and control the flow of electricity as appropriate for their specific operations.Remote condition monitoring prevents unexpected downtimeWhile many wind farm owners today recognize the value of SCADA systems, many have yet to discover the advanced condition monitoring solutions now available in the marketplace. (Some suppliers may also call them predictive maintenance systems.)  A condition monitoring system provides remote sensing, monitoring and recording of any irregularity detected in the wind turbine equipment – whether it is occurring in turbine blades, gears, gearboxes or other components. The irregularity might be an unusual vibration, a deviation from the norm in the control system, or some other early indication of a potential malfunction or failure.  Owners and operators of wind farms cite gearboxes, gears and bearings as being the most problematic components.  The addition of sensors on critical moving parts, particularly gearboxes and the main shaft, can be a smart approach.  Since wind turbines are among the largest and most expensive rotating mechanisms on the planet, a reliable, sensor-based condition monitoring system is a cost-effective and worthwhile investment that can yield significant savings by helping to prevent major equipment breakdowns and downtime.As the demand for wind power continues to increase in the marketplace, the demand for SCADA and condition monitoring systems will also increase. Maintenance of wind turbines is costly, even under the best conditions, but unexpected turbine downtime or failure is prohibitively costly. This is because large cranes and skilled technical workers are required to perform turbine service and repair hundreds of feet in the air.  Worker safety aside, cranes are expensive to rent, difficult to operate, and are in short supply, making service delays even more likely. Consider this: According to one energy industry analyst, just a one percent loss of productivity in a large 100MW wind farm equates to approximately $250,000 in lost revenue. That’s why investing in a high-quality, networked SCADA and condition monitoring infrastructure is so very critical and can provide wind farm owners and operators with a greater measure of confidence in the reliability of their operations. Rugged network switches are essential to reliabilityThree recurring themes in our discussion of SCADA and condition monitoring systems are networking connectivity, real-time information flow, and integrated monitoring and control.  These capabilities are possible only when there are robust and reliable switches in place to connect these systems to the overall communications infrastructure.   Given the importance of monitoring and transmitting the necessary data to ensure maximum uptime, it is crucial that the Ethernet switches used in SCADA and condition monitoring systems are designed to withstand the range of environmental rigors they face. In addition, the switching systems must offer the flexiblity and scalability required to accommodate additional sensor feed equipment or system upgrades in the future.    Key product qualities and capabilities to consider in network switch selection include:•    Rugged, heavy duty construction to withstand mechanical shock and vibration•    MTBF (Mean Time Between Failure) rating greater than 500,000 hours•    Operating temperature range between -40 to +85 degrees Centigrade•    Protection from packet loss in high EMI environments•    Superior protection against ingress of water and dust (e.g., IP 67 enclosures)•    Allowance for highly redundant network design and the ability to “hot swap” malfunctioning switches without taking down the network•    Support for short-haul fiber optical physical media (i.e., cabling) for intra-substation networking and long-haul fiber optic media for high-speed Ethernet (100Mbps)SCADA Switches for the Real WorldIndustrialENET, a leading supplier of industrial networking equipment and engineering services, has pioneered the design of network architecture for companies in the wind power industry.  Since 2000, the firm has worked with OEMs, system integrators and developers to provide Ethernet networks and SCADA solutions for wind farms.   To maximize productivity in one project, IndustrialENET’s wind farm architecture needed to provide uninterrupted, near deterministic flow of large amounts of data between turbines, substations and operation and maintenance centers. And, since turbines have a lifespan of 20 years, the networking components selected had be exceptionally robust, as well.For the infrastructure’s network switches, IndustrialENET specified Hirschmann (a Belden Brand) managed switches, which offered the ruggedized construction and built-in redundancy required for reliable, uninterrupted performance.  On the redundancy side, a single pair of Hirschmann MS4128-5 Gigabit switches can accommodate a Gigabit HIPER Ring between them and also provide redundant connections to 20 or more 100MB Sibling Turbine Rings. Each of the Rings, whether Parent or Sibling, can have up to 50 switches each.   In specifying SCADA and condition monitoring systems and components, clearly it pays to take the time to evaluate marketplace offerings and invest in the most robust products you can find.  The ROI will be increased confidence and peace of mind that your information and communication systems will perform reliably and well for many years to come.  

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