Design and implementation of an optical high voltage sensor using BGO crystal waveguide / Asmaa Mohamed Saber Elbasiouny ; Supervised Salah Elden Ibrahim Hasseb Elnaby , Rabah Yousif Amer , Jala Mahmoud Elazab

Thesis (M.Sc.) - Cairo University - National Institute of Laser Enhanced Science - Department of Laser Application in Engineering

Voltage transformers (VT's) are one of the most common conventional methods of measuring high voltage. However they suffer from some major problems such as the interference resulting from additional load, limited bandwidth and relatively bulk size and high cost due to the requirement of many voltage dividers. Recently, optical techniques of measuring electric power, either current or voltage, gained a great interest in virtue of electrical isolation, elimination of the electromagnetic interference, high precision and accuracy, wide bandwidth from DC to GHz, compact size and low cost. Based on the linear electro-optic effect, 2pockels effect3, linearly polarized light propagating in the Pockels crystal (BGO) parallel to the electric field will experience phase retardation between its components in the slow and fast axis. The phase retardation is due to the difference in the velocity of propagation of the light and is related to different refractive indices of the axes which are proportional to the applied electric field. The value of the phase retardation indicates the value of the voltage difference through the crystal. The sensitivity of the optical Pockels systems in longitudinal configurations was limited by the value of the maximum detectable voltage (Vs). In order to overcome the limitation of previous systems a modified system is designed, constructed and tested based on the transverse pockels effect in which the electric field direction is perpendicular to the direction of light propagation

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