Simplifying remote access for data aggregation and performance assessment

Most wind turbine SCADA systems lag behind conventional industrial SCADA systems in terms of development.

Conventional or Industrial SCADA systems are typically offered by vendors who only sell OEM control gear and equipment and or only SCADA software.

The products offered by industrial SCADA system suppliers are competitive in their own right. Typically a wind turbine's SCADA system is not optional and a typical wind turbine supplier would be very reluctant to supply turbines that would connect directly to a 3rd party SCADA system. Thus there is a 'monopoly' in that the developer has to take the selected turbine supplier's SCADA system.

As SCADA systems are not the core business of turbine suppliers and constitute a low percentage component of the total turbine contract they are not the key focus of the turbine supplier.

In addition the SCADA system is not a key differentiator between turbine options, i.e. a specific turbine type for a project would rarely be chosen on the merit of the SCADA system.

However when selecting an industrial SCADA system the features, benefits and costs of that system are usually key to its selection.

Thus in this competitive arena industrial SCADA systems develop features and tools to attract customers and differentiate their products. Additionally they must be user friendly and well supported if they are to expect repeat business and positive feedback in the market.

There is a broad range and quality of wind turbine SCADA systems available from turbine suppliers.

According to the specialists in the industry, the best come close to those offered by industrial systems and the worst are 10-15 years behind what could be expected. Turbine suppliers are often reluctant to modify, add or develop special features or options for a specific client and in many cases these features are then developed on an additional SCADA system which sits alongside the turbine supplier's system.

A number of turbine supplier SCADA systems often come with a range of optional add-ons such as reporting tools, and access privileges which are additional cost items, which in many cases and markets are essential to the operation of the wind farm.

These options are not priced at a competitive level, but a price that the developer can stand.

There are some significant advantages with wind turbine SCADA systems over conventional industrial systems.

They are preconfigured, set up and proven with the supplied turbines, they often integrate complex visuals, such as power curves and wind roses, which would require development in an industrial application, and are supplied as part of the total wind turbine contract.

Enhancement with web technologies
Usually the choice of SCADA system is not a competitive process, and depends upon the choice of turbine supplier who then provides the SCADA system. In addition the provision of SCADA is not a core business of the wind turbine supplier.

Nevertheless, very significant progress is being made and many SCADA systems can be accessed via a web interface. This enables simpler remote access for data aggregation and performance assessment and therefore distributed performance assessment. Another key feature of web interfaces is that they enable small scale operators to access the performance assessment benefits that previously would only have been available to larger scale operations.
The industry has witnessed the development of a SCADA system, based on web technologies, including XML, XSL style sheets, Microsoft Internet Information Server (IIS) and ASP.

With their flexible architecture, the system can be adapted to project-specific requirements, customised data and report formats.

The web server on site generates reports and stores historical data and remote terminals can be connected via modem, routers or an Ethernet network.

On site, the SCADA system and the wind turbines are linked with an internal communication network using optical fiber cables. Depending on the site layout, the network is split into loops each consisting of 8 to 10 turbines.

In terms of output, the communication driver, which controls the site network, is fully configurable and can be set up to handle any project-specific combination of turbines, net masts, grid monitoring stations, etc. The report generation engine offers customised reports as well as a number of predefined reports with setup based on typical wind farm operator requirements.

The web server delivers information such as reports and real-time data mostly based on XML and XSL style sheets. It can be expanded easily to provide project-specific pages.

Wind Energy Performance Optimisation Summit's Wind Energy Performance Optimisation Summit is scheduled to take place on 11th - 12th February 2009 in Hamburg, Germany).

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