A compact ATEX solution for an existing turbine installation

In LM gas turbines, the position of the variable stator vane system needs to be reliably monitored to support stable compressor operation. For one LM2500 application, an obsolete measurement solution had to be replaced with a compact ATEX-certified sensor that could fit within the existing turbine installation.

(Image above: AI-generated illustration based on the actual application. Some details have been modified to protect confidential customer and some technical information)

Replacing an obsolete position sensor

Variable stator vanes help control airflow through the compressor and support stable operation across changing turbine conditions. Their position therefore needs to be reliably measured during operation.

The existing measurement solution was no longer available, creating a replacement challenge. A new sensor not only had to provide the required position measurement, but also had to match the available installation space and existing mechanical configuration.

At the same time, the solution had to meet the applicable ATEX requirements and withstand the environmental and temperature conditions associated with the turbine installation.

Matching the existing turbine installation

Rather than redesigning the installation around a standard sensor, the position measurement solution was adapted to the existing mechanical configuration.

The X117 linear position sensor was selected because of its compact dimensions, ATEX certification and suitability for integration into the available space. Several mechanical aspects were adapted to suit the application, including the installation and mounting arrangement.

A dedicated mounting bracket was developed to position the sensor correctly within the existing construction.

This made it possible to replace the obsolete measurement solution while retaining the surrounding turbine configuration.

From sensor signal to the control system

The X117 is connected to the control system through an X005 galvanic isolation amplifier. Together, the sensor and isolation amplifier provide a position measurement solution suitable for hazardous-area applications, while transferring the required signal to the control system.

The main selection criteria were:

The main selection criteria were:

ATEX suitability
Compact sensor dimensions
Compatibility with the existing mechanical installation

Measuring without entering the turbine package

The new position measurement allows the variable stator vane position to be monitored without personnel having to enter the turbine package during operation to verify the position locally.

This reduces the need for personnel to access the operating environment while making the required position information available to the control system.

The result is a safer and more practical way to monitor the variable stator vane system during turbine operation.

Tested for the LM2500 application

The customised solution has successfully passed testing for the LM2500 application. The same measurement approach also provides a basis for adaptation to other LM2500 configurations or comparable gas turbine applications where existing mechanical constraints, hazardous-area requirements and reliable linear position measurement need to be combined.

Replacing an obsolete position sensor does not always require redesigning the complete installation. Althen can adapt position measurement solutions to existing mechanical interfaces, installation space and environmental requirements.