The Temperature Curve of the Transformer.

Fiber-optic online temperature measurement with the MSENSE® FO system

Your Benefits
at a glance

  • Continuous, real-time recording of the winding temperature
  • Early detection of potential hotspots, enabling service-life management
  • Effective overload management with ETOS®
  • Maximum reliability and availability through internal reference sensor
  • Easy integration into the design and value chain of a power transformer
  • • Connection to SCADA

Detecting hotspots at an early stage

  • According to a study by CIGRE, winding problems are the cause of 45% of transformer failures.
  • An increase of just 12°Cin the winding temperature drastically reduces the service life of the transformer by 75%.

Prevention of costly transformer failures

The MSENSE® FO system accurately depicts the winding temperature continuously in real time. It therefore shows the thermal state of the transformer at all times. As an early warning system, MSENSE® FO supports operational security and ensures a long service life.

Conventional winding-temperature thermometers provide a calculated, average depiction of the temperature profile. The fiber-optic MSENSE® FO system does more. In particular for critical and key applications, the early and accurate detection of hotspots can make all the difference.

MSENSE® FO for maximum reliability

The MSENSE® FO innovatively combines several assemblies into a robust solution design for fiber-optic online temperature monitoring. The practical and flexible MSENSE® FO system for your power transformer is the result of combining decades of experience in the field and a great deal of expertise.

Overload and service-life management

Monitoring the thermal loads with MSENSE® FO while also using ETOS® safeguards grid stability and enables responses to dynamic overloads. Monitoring the winding temperature online provides the basis for improved temperature management and, at the same time, enables data-based service-life and asset management. The interplay between MSENSE® FO and ETOS® is preconfigured and fits into the world's first open operating system for intelligent transformers. A connection to SCADA systems common throughout the world is also available as an option.

Based on many years of practical field experience and industry-leading expertise, details have been integrated into the fiber-optic sensor that fit seamlessly into the design and the value chain of a power transformer.

The user-optimized solution goes beyond the requirements of ASTM D3426 and D-149, and has a very low partial discharge (< 2 pC).


The use of first-class materials combined with high-quality production and testing technology also ensures a coherent and field-optimized overall concept for the add-on accessories. This not only fits seamlessly into the design and value chain, but also takes the environment and application into account to the highest degree.

Optical single bushing

Leak-tested mounting flange

Cover housing (IP65)

Optical connection line

Bundled optical connection line


The symbiosis of optimized sensor technology with sophisticated electronics and data preparation is integrated into a customer-oriented overall solution.

Depending on the application and application requirements, you can choose between different versions and optional extensions.

Stand-alone solution: MSENSE® FO ECU-S
Integration into ETOS®: MSENSE® FO ECU-I
(Both with MSET FO evaluation software)

Electronic unit for monitoring the winding temperature

Electronic unit for direct integration into ETOS®

MSENSE® FO testing unit (accessory for transformer assembly)