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This article presents a proposal for an alternative approach for simultaneous measurement of electric current and temperature using an optical sensor based on magnetostrictive material that employs a single Fiber Bragg Grating (FBG). The sensor head is of simple design and allows easy installation on the existing conductors of the underground distribution network. This proposal measures the root mean square (RMS) current from 50 to 600 A at any temperature between 10°C to 60°C, real values for a distribution network. The approach consists of obtaining surface curves of two key parameters of the sensor’s waveform response, $\lambda ({t})$. The main parameters are the peak-to-peak and minimum wavelengths as a function of temperature and current. When determining these parameters from the waveform, the crossing point of the contour graphics is used to uniquely determine the current and temperature in the sensor head in real-time, without the need for any correction process. [ABSTRACT FROM AUTHOR]

In this paper, we proposed a sealing method of fiber Bragg grating (FBG) in pressure sensors using electroless nickel-plating. The sensor is designed to be used in harsh environments of thermoelectric power plant engines. In order to be applied in the engine injector nozzle, the FBG has just a single attached point in the pressure sensor and the combustion chamber pressure will freely compress the FBG. The fixation material used to seal the FBG in the pressure sensor is the key for the sensor performance considering the engine environment used in thermoelectric power plant. Typical level of pressure in the engine monitoring point is around 200 bar and the temperature exceeds 300 °C. We detailed the method of fabrication and the characteristics of this method. Next, the FBG pressure sensors using electroless nickel-plating sealing were studied and submitted to laboratorial and field trial evaluation. In addition, we evaluated the signal characteristics of the FBG pressure sensor and we compared it with a standard pressure sensor used in this application. [ABSTRACT FROM AUTHOR]