Climate Check for Wind Turbines

Wind turbines are technically highly complex systems in which the kinetic energy of the wind is captured as rotational energy and transferred to a generator where it is converted into electricity. This requires a large number of electronic components, which are installed in wind turbines from head to toe. Accordingly, correct thermal management is also an important issue. Electronic devices always require reliable temperature conditions, must not overheat but also must not be operated below a permissible temperature specification. Condensation can also cause serious damage to the electronics. In addition, offshore installations in particular are subject to adverse environmental conditions that need to be taken into account.

Perfect thermal management for wind turbines

The Smart Sensor CSS 014 from STEGO is designed to reliably record temperatures and humidity and transmit the data via suitable interfaces so that operators always have a reliable overview of thermal conditions and changes in wind turbines. The sensors create a better data situation by continuously providing precise information about the climatic conditions inside the system. On this basis, air conditioning components can be precisely controlled to regulate temperature and humidity accurately, ensuring ideal operating conditions.

Thanks to the optimized control, the components are subjected to less stress and are protected from damage caused by condensation or overheating . As a result, the service life of wind turbines is extended and failures are reduced. Fewer breakdowns in turn mean lower maintenance costs and higher system availability, which ultimately saves costs and secures profits.

The CSS 014 Smart Sensor from STEGO was developed precisely for this purpose in response to the requirements of a wind turbine manufacturer and, thanks to its efficiency and general digitalization, has now established itself in numerous other industries, including the charging infrastructure for electromobility (see box text).

Wind power on the rise

There are currently 1,566 offshore wind turbines in Germany, divided into 29 wind farms located off the North Sea and Baltic coasts. They now generate 8,465 MW of rated power per year (as of 2023) ^*1, which is over 7,000 MW more than ten years ago. (In the UK, the figure is already 14.7 GW and in China 37.3 GW).

The German government's goal is to install a minimum of 70 gigawatts of offshore wind energy in German waters by 2045 . These expansion targets were even adopted in the form of an amendment to the Wind Energy at Sea Act (WindSeeG).

While offshore still currently ranks fourth in terms of gross electricity generation from renewable energies in Germany with 23.8 TWh, onshore wind power is the frontrunner with 120.9 TWh and has increased by over 30 percent compared to 2021. ^*2

According to EnBW, however, in order to achieve the climate targets by 2030, additional wind turbines with 10,000 MW would also have to be built in this segment. Wind power is therefore one of the most important pillars when it comes to supplying energy with green electricity. And its expansion is making increasing progress.

Fail-safe thanks to reliable remote diagnostics

To ensure safe and reliable power generation, it is important to monitor the sensitive electronics in wind turbines and carry out regular maintenance - an expensive business, especially when it comes to offshore turbines. This is because they are often difficult to access, difficult to reach and the harsh weather conditions on the high seas make working there a challenge.

Condition monitoring systems are used for remote diagnostics in order to keep the systems under constant control. The complexity of the electronics is therefore constantly increasing. To protect them and prevent technical failures, the CSS 014 Smart Sensors from STEGO are part of the systems. The sensor represents the digital evolution in the thermal management of electronic components. It measures the important parameters of temperature from -40 °C to 80 °C and relative humidity from 0 to 100 % RH and therefore allows important conclusions to be drawn about the operation of the system. If the temperature in the wind turbine is too high or too low, the device signals the need for action, as important components and therefore functions are at risk of failing. Thanks to an additional histogram of all measured data, you always have a reliable overview of the turbine status.

Flexible and easy to integrate thanks to IO-Link

STEGO opted for IO-Link as the communication protocol. This means that the smart sensor can also be easily parameterized for use in wind turbines using interface software on a PC. IO-Link also ensures flexibility, as sensors and actuators from different manufacturers can be easily integrated using standardized interfaces . The cabling effort is also kept to a minimum thanks to IO-Link with standardized, unshielded cables with at least three cores. Installation is simple, which ultimately reduces time and costs.

The data collected is transmitted to a higher-level system controller via IO-Link. In addition to the pure switching parameters for temperature and humidity, the user also has access to additional configurable "events" . The keyword here is value-added data. As IO-Link enables access to extended diagnostic data and device parameters, monitoring and maintenance can be individually adapted and optimized depending on the application scenario. The central configuration and parameterization of the devices make commissioning and subsequent changes much easier.

In summary, IO-Link combines simple installation with flexibility, increased data availability and cost efficiency.

In some systems, the Smart Sensor is also used in a 4-20 mA version. As STEGO has been active in the wind power sector for many years with its thermal management products, the Smart Sensor CSS 014 fits perfectly into the portfolio consisting of hygrostat, filter fan, fan heater, thermostat and LED lighting.

Sustainable electronics protection 

The sensor unit itself has been developed to adapt perfectly to the harsh operating conditions on the high seas. The thermal management experts at STEGO have thermally decoupled the device and encapsulated it with a circumferential seal, resulting in high vibration resistance and IP57 protection in the area of the sensor. The microcontroller, interface driver and EMC protection unit are arranged in a heat-optimized way on the protective lacquer-coated circuit board of the CSS 014, so that any influence on the measured values due to waste heat is virtually eliminated.

Not only can reliable remote diagnostics be carried out using the measured values, the control of the entire wind turbine can also be optimized and individual devices such as fans, cooling units or heaters can be controlled according to demand . The higher-level control system uses the transferred data to decide which actions need to be carried out. For example, actuators can be controlled with pinpoint accuracy in order to achieve the desired operating status or to guarantee the desired environmental parameters.

Advantages compared to classic two-point control

The control of air conditioning components such as heaters and fans via a temperature and humidity sensor in combination with a system controller offers significant advantages over a classic two-point controller: While the two-point controller merely switches between two states (on/off), the sensor-controlled system enables more precise and continuous adjustment of the air conditioning. This enables the system controller to adapt the operation of the air conditioning components more precisely to the actual demand. Unnecessary switching on and off is prevented, which reduces energy consumption and extends the service life of the components.

Overall, the sensor-based control system contributes to more efficient, more precise and longer-lasting operation of the components . Necessary repairs are also reduced, which is a significant cost factor, especially on the high seas. The Smart Sensor CSS 014 is of course also suitable for use in onshore wind turbines. The applications and functions remain the same. In the offshore sector, remote maintenance just plays a more important role, simply in terms of the accessibility of wind farms on the high seas.

^*1 Statistics, survey by Deutsche WindGuard, "Status of offshore wind energy expansion in Germany"

^*2 Survey by BDEW; ZSW; Federal Statistical Office, annual report "The Energy Supply 2023"

Use in the charging infrastructure for electromobility

The Smart Sensor CSS 014 from STEGO is very cost-efficient, so it is also worth using for smaller applications. One example of this is the charging infrastructure for increasing electromobility. Heat is generated during the charging process, which can lead to a large temperature difference between the inside of the charging station and the outside temperature. This can lead to condensation forming inside the charging station, which in the worst case can cause the electronics to fail. Overheating due to waste heat during the charging process or ambient temperatures that are too low - especially in winter - can also damage the electronic components.

The Smart Sensor CSS 014 ensures ideal thermal management in these applications. It continuously measures the temperature and humidity inside the column. This means that the prevailing conditions in the charging station can be reliably monitored and measures taken in good time to prevent damage. This prevents failures, reduces operating costs and increases the availability of the charging stations.