Redundant safety unit enhances wind turbine protection

Older wind turbines are still critical to renewable energy generation but often operate on outdated systems. These legacy systems can struggle to meet modern safety and performance standards, particularly when it comes to preventing overspeed events and maintaining reliable operation in harsh environments.

Overspeed - a condition where turbine blades rotate faster than their design limits - can lead to severe damage, including mechanical failure and generator breakdowns. To prevent such risks, precise monitoring and redundant safety measures are essential. However, retrofitting older systems with advanced safety solutions can pose integration and operational challenges.

The solution: PR electronics 4225A – A flexible, redundant safety unit

PR electronics’ 4225A provides a robust solution for enhancing safety in wind turbine control systems. This device integrates seamlessly into existing systems and operates independently as a redundant safety unit.
 

Key features of PR electronics 4225A:

• Redundant monitoring: Equipped with a PNP input, the 4225A monitors rotor speed to detect overspeed events. If the rotor exceeds 120% of the rated speed, the device triggers a safety shutdown via a relay, safeguarding the turbine.
• Standalone functionality: Operates independently from the main turbine controller, ensuring an additional layer of safety in case of main system failure.
• Programmable and user-friendly: The 4225A is configurable through detachable displays (4510 / 4512) and supports local and convenient programming via the PPS app.
• Safety system qualification: The 4225A provides the required failure data (SFF and PFD_AVG) for SIL 2 applications as per IEC 61508 / IEC 61511.
   

Real-world application: Safety in action

A machine builder specializing in control systems for older wind turbines successfully integrated the 4225A into its retrofit designs. By using the 4225A to monitor rotor speed and detect input drift, the company ensured its turbines met modern safety requirements while maintaining optimal performance.

In practice, the 4225A prevents overspeed and sensor drift by:

1. Measuring rotor speed through the PNP input.
2. Triggering a safety relay if the speed exceeds a predefined threshold (e.g., 120% of rated speed).
3. Providing secondary speed signal to main controller to detect sensor drift, comparing speed readings from system A and B.

This redundancy protects the turbine and significantly reduces the probability of a catastrophic failure event.