Technology

How to prevent Wind Blade Turbine Icing? – With the WIPS Technology

Wicetec Ice Prevention System (WIPS) prevents ice formation on wind turbine blades, which means continuous energy production and lower maintenance costs for wind power plants.

Benefits:

More production, when it matters – Continuous production through the winter’s icy days.
Lower project financing costs – Better project bankability as ice induced uncertainty on long-term production estimate can be eliminated.
Reduced balancing costs – More accurate short-term production forecasts.
Energy efficient – Efficient surface heaters and intelligent control optimize the heating energy usage.
Less wear and tear on turbine components – No ice induced standstills and re-start attempts, thus wear and tear of other components is reduced.

Download Wicetec Technologies brochure (pdf)

Comparison of wind turbine with and without WIPS. Turbine with WIPS follows the expected power, whereas the turbine without is hardly starting.

Fields of application

New installations – WIPS components installed in wind turbine and blade factories:

WIPS technology has been fitted to numerous different wind turbine models. Integration to a wind turbine is possible due to modular design and flexible interfaces. Electrical and control cabinets are designed and made very compact without deteriorating functionality and reliability. The carbon fabric blade heating element production steps can be integrated into typical blade production process and line relatively easily. The heating element materials and production method are similar to normal blade production.

Retrofits for existing wind turbines

WIPS can be fitted to wind turbines which have already been installed. The system is the same as for new wind turbines. Only logistics differ from new installations. The retrofit installations are carried out as following: the original blades are taken down, moved indoors for heating element installation and lifted back up again after installation. The heating elements are installed indoors for two main reasons: it enables high quality lamination process in controlled conditions, and it minimizes weather risk for project schedule on windy site.

Recommended for sites with AEP losses > 3%.

Patented heating element technology

WIPS blade heating elements are the result of extensive research, development and testing: high tech electrical heaters. Heaters are made of carbon fabric, which gives several benefits over other heater types.

Carbon fabric conducts electricity just perfectly: the surface of the blades can be heated enough to prevent the ice build up. It is important to have quick heating response after ice detection to keep the blade free from ice. However, it is also important not to heat the blade too much to avoid degradation of blade material properties. The glass transition temperature of matrix material must be avoided.

Heater is located outside the blade structure..

Blade heating elements protects from icing the area critical to energy production. Heating of complete blade is not reasonable nor efficient.

Example from real life: Clean blade with WIPS heating elements, operating in Quebec, Canada.

The magic is beneath the surface. Infrared thermography testing from factory acceptance tests.

Material testing in laboratory is necessary for successful selection of materials and production methods.

Suitable mechanical properties: Carbon fabric heating elements tolerate the huge fatigue loading, which occurs when they are installed to flexible wind turbine blades. Heater material has been tested in laboratory with mechanical static and fatigue tests, highly accelerated lifetime test (HALT) and interlaminar shear strength (ILSS) testing. But most importantly, WIPS heaters have been tested in field, in actual wind turbines. Oldest heating elements based on this carbon fabric heating technology, an early version though, are still in operation after 20 years of “rotation”.

No effect on aerodynamics: Carbon fabric heater is so thin that it does not affect the aerodynamics of the blades at all. The added layers (heating element and its glass fabric protection layer) are only 0.5 mm thick. The surface is finished with normal smoothing and blade painting to achieve aerodynamic surface where added heaters are not visible. The magic is beneath the surface!

Blade with WIPS looks and feels like a normal blades, no effects on aerodynamics.

Lightning Protection

Lightning protection of WIPS is coordinated together with the blade and wind turbine lightning protection. Successful incorporation of WIPS requires that the wind turbine lightning protection is according to IEC 61400-24 standard. Lightning protection of the heaters is based on three aspects:

Direct strikes to the heaters must be minimized. This is done with the blade lightning receptors and location of the heater. Additional receptors or relocation of existing receptors might be needed.
Flashovers, uncontrolled voltage breakthroughs, are prevented by equipotential bonding of lightning protection system and heating system. Specific high energy surge protective devices are used between the two systems.
Wicetec heater components are tested to withstand the conducted lightning current exposure.

WIPS technology has been integrated to several different blade designs and have been tested to fulfil the requirements of IEC standard by Wicetec clients.

Full scale high voltage lightning tests.

Carbon fabric heating elements in high current tests.

Ice detection and control system

Control of WIPS is fully automatic, Wicetec controller takes care of ice detection and heating control:

Anti- and de-icing modes
Ice detection with multiple source algorithm: meteorological ice detection combined with power curve ice detection. Ice detection and system activation can also be done by turbine controller.
Heating control is done with Wicetec Blade Temperature Estimator, which is a virtual blade temperature sensor. Traditional temperature sensors are NOT needed in blades. Read more about Wicetec® BTE here.
Communication with wind turbine controller.

WIPS control and electrical system is modular and can be installed into different type of wind turbines.

Interested in ensuring that your blades keep spinning through the winter?