Kamil Barczak

Optical fiber sensors of magnetic field applying Faraday's effect

This work presents a system for magnetic field intensity measurements. The idea of measurements is based on an influence of external magnetic field on the polarization state of singlemode light propagating along optical fibers. In the paper some experimental results of testing investigations of the system for measurements magnetic field of high intensity are presented. The final aim of the investigation outlined below is to work out magnetic field intensity sensors which, together with optical fiber temperature sensors and electric field intensity sensors, will make possible, in the future, to monitor fully operation of electromagnetic power units such as, for example, high voltage power transformers.

D-type fibers for magnetic field sensing: theoretical analysis

The paper deals with theoretical analysis of new optical fiber structures of D-type which may be applied in optical fiber sensors of electric current. This analysis is based on the following points: light propagation analysis and elastooptic effect induced by magnetostriction effect in optical fiber structures. The main point presents theoretical analysis of magnetic field influence on light propagation. D-type fibers have been designed, produced and tested. The results of measurements of the magneto-optical effect and the distribution of mode fields in such optical fibers have been presented.

Investigation of optical fiber current sensor with external conversion in AC magnetic field

This article presents results of a research on an optical fiber current sensor with external conversion (OFCS-EC). Presented OFCS-EC works on the principle of the Faraday effect. The active element in a sensor head was made of the reliable glass characterized by a high Verdet constant. The sensor was investigated in alternating magnetic field. The sensor was investigated in a configuration known as the optical fiber current transducer (OFCT). In this configuration an electric conductor was a source of a magnetic field. The variations of a output signal is a result of the Faraday effect in the sensor head. Investigations presented in this paper are focusing on checking whether a response signal from the OFCS-EC registered in condition closed to an industrial environment. The results of these investigations have proven very good stability and linearity of the output OFCS-EC signal.

Optical fiber current sensor with external conversion for measurements of low AC electric currents

This article presents results of research on an optical fiber current sensor with external conversion (OFCS-EC), which was presented in article [1]. In this article the research is concentrated on an analysis of the sensor toward its application in power protection automation systems. For this purpose a busbar, designed for an operation in a current range up to 200 A, was selected. Such basbars are used in low voltage electric substations. A proper orientation of the OFCS-EC sensor head was chosen basing on calculations of a spatial magnetic field distribution round the busbar. Measurements were carried out in laboratory conditions. The sensor was placed in an alternating magnetic field generated by an air magnetic coil. A value of magnetic field induction generated in the coil corresponded to conditions round the busbar for given intensity of electric current conducting in it. Investigations presented in this paper are focused on checking whether a response signal of the OFCS-EC in conditions corresponding to the ones prevailing in an industrial environment. The results of these investigations have proven linearity of a response signal. Uncertainty of measurements of electric current was 18 A for current effective value 200 A.

Optical fiber current sensor with external conversion

This article presents results of research on an optical fiber current sensor with external conversion (OFCS-EC). The sensor setup presented in the scope of this paper was developed from the optical fiber magnetic field sensor. The OFCSEC works on the principle of Faraday effect. Therefore, the active element of the sensor was made of the reliable glass showing high Verdet constant. The sensor was characterized by its sensitivity in a optoelectronic current transformer setup for static magnetic field. Investigations presented in this paper are focused on checking, whether parameters of the OFCS-EC are stable during long term measurements. The results of those investigations have proven excellent stability of the proposed OFCS-EC.

Investigation of magnetooptic effects in special optical fibers type D

The paper deals with investigations concerning new optical fiber structures type D which may be applied in optical fiber sensors of electric current. These structures have been designed, produced and tested. The results of measurements of the magneto-optical effect and the distribution of mode fields in such optical fibers have been presented, as well as the test stand designed for investigations of magneto-optical phenomena.

Investigation of magneto-optic effects in optical fibers

This work presents the new method that allows determining the polarization state of light which propagate in optical fibers. One shown also the experimental results of application the elaborated method for mesaure of magnetic field of high inteisty. The final aim of this investigation will be the elaboration of magnetic intensity sensors, which together fiber optic temperature sensors and intensive of electric field sensors make possible, in the future, to monitor the state of work of electromagnetic power arrangements, first of all - high voltage power transformers.