Grzegorz Fusiek

A Fiber-Bragg-Grating-Based Sensor for Simultaneous AC Current and Temperature Measurement

In this paper, a sensor that is capable of measuring both ac current and temperature using a single fiber Bragg grating (FBG) is described. The device consists of a magnetically biased magnetostrictive alloy bonded to an FBG. The magnetic field generated by the current in a specially designed coil produces internal strains in the magnetostrictive alloy which can be detected by the FBG. The temperature at the sensing point is determined through averaging of the sensor output signal. The measurement range of the sensor can be varied by altering the design of the sensor coil. A prototype sensor that is capable of measuring ac currents up to 1 A has been constructed while simultaneously measuring temperatures of up to 100 degC

A fibre Bragg grating based sensor for simultaneous AC current and temperature measurement

In this paper, we describe a sensor capable of measuring both AC current and temperature using a single fibre Bragg grating (FBG). The device consists of a magnetically biased magnetostrictive alloy bonded to an FBG. The magnetic field generated by the current in a specially designed coil produces internal strains in the magnetostrictive alloy which can be detected by the FBG. The temperature at the sensing point is determined through averaging of the sensor output signal. The measurement range of the sensor can be varied by altering the design of the sensor coil. A prototype sensor has been constructed capable of measuring AC currents up to 1 A while simultaneously measuring temperatures up to 100/spl deg/C.

Hybrid fiber optic voltage sensor for remote monitoring of electrical submersible pump motors

We report on the design and experimental evaluation of the hybrid fiber Bragg grating (FBG) piezoelectric voltage sensor developed specifically for remote monitoring of electrical submersible pump (ESP) motors. Unlike a previously reported transducer based on a single piezo- electric element, the voltage rating of the presented device could be as low as 500 V due to the use of a multilayer piezoelectric stack as the primary voltage-to-strain transducer. This enables the use of such sen- sors across a wider range of ESP applications, which often have subki- lovolt voltage ratings. In addition to the design details, we present details of the full characterization of the device, including the hysteresis and temperature-dependence characteristics and discuss ways of eliminating or reducing these effects. We also demonstrate that the sensor can be used to simultaneously measure voltage and temperature.

Design and evaluation of a pre-prototype hybrid fiber-optic voltage sensor for a remotely interrogated condition monitoring system

In this paper we give details of the design and laboratory evaluation of the pre-prototype hybrid fiber Bragg grating piezoelectric voltage sensor for a remotely interrogated condition monitoring system, such as the measurement system used for monitoring of electrical submersible pump (ESP) motors. The proposed sensor design is directed towards the upper voltage rating (5 kV) of ESP motors.

Interrogation of extrinsic Fabry-Perot interferometric sensors using arrayed waveguide grating devices

In this paper we present details of a solid state interrogation system based on a 16-channel arrayed waveguide grating (AWG) for interrogation of extrinsic Fabry-Perot interferometric (EFPI) sensors. The sensing element is configured in a reflecting mode and is illuminated by a broad-band light source through an optical fiber. The spectrum of light reflected from the sensor is analyzed using an AWG device acting as a coarse spectrometer. Using measurement points from the AWG channels, the original spectrum of the sensing element is reconstructed by a means of curve fitting. This allows sufficient information for the position of the reflection peak (or inverted peak) to be uniquely determined and the value of a measurement quantity obtained. In addition to the theoretical simulations of the proposed measurement system, we provide details of the laboratory evaluation using an EFPI strain sensor.

An Optically-Interrogated Rogowski Coil for Passive, Multiplexable Current Measurement

We report on the design and implementation of a novel hybrid electro-optical sensor for the measurement of electric current. A fibre Bragg grating is utilized to passively interrogate an air-cored coil via a low-voltage piezoelectric multilayer stack. Peak Bragg reflections are strain-tuned by the Rogowski coil/piezoelectric transducer combination, allowing primary current reconstruction to be performed remotely and without active electronics at the sensor. The preliminary embodiment demonstrates long-distance, passive measurement of current for metering and protection relaying applications, and retains the fiber transducers capability for serial multiplexing.

Extended step-out length fiber Bragg grating interrogation system for condition monitoring of electrical submersible pumps

We present details of the design and laboratory evaluation of the fiber Bragg grating (FBG) interrogation system developed specifically for condition monitoring of electrical submersible pumps (ESPs). The system, based on the microelectromechanical systems (MEMS) Fabry-Pae#169;rot tunable filter, is capable of interrogating several FBG sensors placed around an ESP unit and configured to measure static and dynamic parameters, e.g., temperature, vibration signature and/or instantaneous voltage, and current. Sensor interrogation over the extended step-out length distance of 24 km is demonstrated in the laboratory in a simple experiment of multipoint dynamic strain monitoring in a vibrated cantilever beam.

Dynamic strain measurement using an extrinsic Fabry-Perot interferometric sensor and an arrayed waveguide grating device

In this paper, we demonstrate an interrogation system, based on an arrayed waveguide grating, capable of monitoring dynamic strain in a cantilever beam at frequencies up to 5 kHz (limited by the actuator) with a similar precision to resistive strain gauges.

Hysteresis compensation for a piezoelectric fiber optic voltage sensor

We present details of numerical techniques developed to compensate the effects of hysteresis experienced by a hybrid piezoelectric fiber optic voltage sensor. The techniques, implemented using a real-time signal processing system, are tested and their effectiveness evaluated experimentally. The best of the proposed algorithms provides phase error compensation from approximately 7 to nearly 0 deg, and allows us to perform sensor calibration to achieve accuracy better than 0.5% (full scale output).

Single-Ended Differential Protection in MTDC Networks Using Optical Sensors

This paper presents a method for rapid detection of faults on voltage source converter multiterminal HVdc transmission networks using multipoint optical current sensing. The proposed method uses differential protection as a guiding principle, and is implemented using current measurements obtained from the optical current sensors distributed along the transmission line. Performance is assessed through detailed transient simulation using MATLAB/Simulink models, integrating inductive dc-line terminations, detailed dc circuit-breaker models, and a network of fiber-optic current sensors. Moreover, the feasibility and required performance of optical-based measurements is validated through laboratory testing. Simulation results demonstrate that the proposed protection algorithm can effectively, and within very short period of time, discriminate between faults on the protected line (internal faults), and those occurring on adjacent lines or busbars (external faults). Hardware tests prove that the scheme can be achieved with the existing, available sensing technology.