Solutions for rotor blade monitoring

Overview

Rotor blade  

Detect vibrations and loads in rotor blades

  • Rotor blades are subjected to extreme environmental conditions and strain. Due to the ever-increasing length of blades, growing demands are placed on monitoring.
  • Rotor blade tension monitoring (RBTM) from Phoenix Contact continuously monitors the stress and loads placed on rotor blades.
  • In the event that the set limit values are exceeded, alarms are triggered: operators are always kept informed of the condition of the blades.

Application

The rotor blades are critical components of a wind turbine generator. Their monitoring becomes increasingly important with the continuous trend towards longer blades. The rotor blades are subject to large dynamic forces which over the service life can lead to structural damage to the blades.

Damage can be detected early by continuously monitoring loads and vibrations. This data allows the perfect load-based regulation of the wind turbine generator, thereby reducing the stress on the blades to a minimum. If damage is caused to the blades, it will be detected early and repairs will require minimal effort. By recording the load spectrum, changes in the structure are monitored throughout the entire service life of the blade.

Solution

Condition Monitoring function  

Detecting weak points in the blades at an early stage

The Tension Monitoring System (RBTM) measures load characteristics and bending moments in rotor blades. For this purpose, strain gauges are attached to the inner side of the rotor blades of a wind turbine generator close to the blade base.

The core element of the solution is the ILC 171 Inline controller from Phoenix Contact. The controller is connected to the sensors in the rotor blades via directly connected Inline modules. To protect the system against surge voltages and lightning strikes, protective devices are installed for sensor cables, the antenna input of the GSM router, and the power supply. As an option, a GSM modem can be used to upgrade the system for direct communication. In addition to the controller interfaces, a PROFIBUS or CAN interface can be integrated to establish an internal bus connection.

The controller acquires the signals of the connected sensors. During this quick signal processing, the measured values are filtered and checked for plausibility. Additionally, the measured values are used to determine the minimum, medium, and maximum bending moment as well as the rotation speed of the rotor. In the event that the set limit values are exceeded, an alarm can be set via freely programmable digital outputs. The processed data is made available simultaneously to the signal scanning by the higher-level controller. Via the network, all raw data can be saved in a Microsoft SQL database or in CSV format, to an SD card or FTP server, and can be evaluated using an independent system. The RBTM also records the occurring load spectrum. The load spectrum formation is used for acquiring vibration amplitudes that cause structural damage to the rotor blades over the entire service life. These values enable the remaining service life to be estimated.

RBTM control cabinet  

Retrofit solution for existing systems

Retrofit installation or new installation

The RBTM can be directly incorporated into the electrical design of the system or retrofitted in existing systems. The retrofit version comprises a fully configured control cabinet, which is built into the hub and can be integrated into the controller via the existing interfaces.

Optionally, the data can be directly transmitted to the operator via the GSM modem. In the case of new installations, the required hardware, such as the controller and I/O modules, is integrated directly into the pitch control cabinets of the wind turbine generator. In this case, the software is transferred to the controller using an SD card.

Your advantages

  • Condition-based maintenance of rotor blades, thanks to early detection of damage
  • Reduced strain on the blades, thanks to load-optimized control of the wind turbine generator
  • Reliable operation, thanks to robust components suitable for the conditions encountered in wind turbine generators
  • Open system for optimum integration into existing systems

PHOENIX CONTACT
SEA Pte. Ltd.

105 Eunos Avenue 3
#04-00
Singapore 409836
+65 6435 9800
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