Michael Willsch

Highly sensitive micro-mechanical fiber Bragg grating acceleration sensor combined with a new multiplexable interrogation principle

The paper describes a micro mechanical Bragg grating acceleration sensor with enhanced sensitivity by force amplification. A new multiplexable and affordable interrogation scheme that uses two overlapping Bragg gratings within the sensor will be demonstrated.

Design of fiber optical high temperature sensors for gas turbine monitoring

Their small size, the multiplexing capability, and the high elasticity of glass fiber can provide reasons to use optical fiber temperature sensors instead of approved conventional thermo couples for temperature monitoring of hot gas turbine components.

Investigation of stator coil and lead temperatures on high voltage inside large power generators via use of fiber Bragg gratings

This paper reports on the first realisation of embedding fiber Bragg grating temperature sensors inside the stator bars and onto the leads of a 200 MVA air cooled power generator. The worlds first measurements of the conductor temperature at high potential during a generator prototype test run demonstrates the feasibility and importance of this measuring technology.

Absolute Phase-Based Distance Measurement for Industrial Monitoring Systems

In this paper, principal considerations for a high accuracy millimeter wave (mmw) radar distance measurement system applicable to be used in harsh industrial environments are presented. The system is based on continuous wave (CW) measurement of the reflection coefficient and interpretation of the signal phase. The ambiguity of the phase is overcome by means of a multiple frequency technique. For absolute distance determination, an online calibration procedure is applied. The applicability of the system is underlined by a laboratory demonstrator measurement.

Fiber Optical Temperature and Strain Measurements for Monitoring and Quench detection of Superconducting Coils

It has been demonstrated that Fiber Bragg Grating Sensors can measure at very low temperatures in Helium cryostats. The intrinsic temperature sensitivity is very low but can be significantly enhance by the thermal expansion of polymer carriers. Temperature and mechanical strain changes can be measured quite accurately.

New approaches for the monitoring of gas turbine blades and vanes

Gas turbines for power generation are being operated on the physical limits of materials and structures. A safe operation requires more monitoring of critical components. Optical, acoustic and RF waveguides could be used to access the harsh environment inside of gas turbines for monitoring purposes.

Optical monitoring of highly stressed infrastructure and rolling stock modules for railway system operation

For the first time online temperature measurements with FBG temperature sensors on railway overhead lines could be demonstrated. All sensors measured successfully under outdoor conditions over a two year period. As a first experimental result the excess temperatures due to current load are small compared to ambient sources of temperature change. In the future this first result will be analyzed under different seasonal and current load conditions. Furthermore the modeling and first field test have demonstrated the possibility to acquire information about the interaction between OCL and current collector via optical strain gauges integrated into conventional current collector strips.

Fiber optical sensor trends in the energy field

The raising demand for increase of efficiency and reduction of costs in power generation causes a mind change and promotes the commercial use of fiber optical sensors for health monitoring and control purposes.

Monitoring of inhomogeneous flow distributions using fibre-optic Bragg grating temperature sensor arrays

Knowledge of the gas flow distributions, their mass velocity and turbulences, in chemical reactors, thermodynamic engines, pipes, and other industrial facilities may help to achieve a more efficient system performance. In our novel approach, optical fibre Bragg grating (FBG) sensors have been used for measuring the temperature of a heated element, adapting the principles of conventional hot-wire-anemometers. Because of the multiplexing capability of FBG sensors, the gas mass flow distribution can be measured along the sensor array. The length of the heated and sensor-equipped element can be easily adapted to the cross section of the gas flow, from <10 cm up to several metres. The number and distances of FBGs distributed over this length defines the spatial resolution and is basically limited by the sensor signal processing. According to FBG sensor lengths < 5 mm, spatial resolutions of gas flow measurements of less than 1 cm can be achieved.

Fiber optical sensors in power generation

The raising demand for increase of efficiency and reduction of costs in power generation causes a mind change and promotes the commercial use of fiber optical sensors for health monitoring and control purposes.