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The last few decades have a wide spread use of optical fibre sensors in many applications. Optical fibre sensors have significant benefits over existing conventional sensors such as; high immunity to electromagnetic interference, the ability to transmit signal over long distance at high bandwidth, high resolution, usage in hazardous environments and no need for isolation when working at high voltages. The measurement of high voltages is essential for electrical power systems as it is used as a source of electrical information for Relay Protection Systems (RPS) and load management systems. Electrical Power Systems need to be protected from faults. Faults can range from short circuits, voltage dips, surges, transients etc. The Optical High Voltage sensor developed is based on the principle that the Lead Zirconate Titanate (PZT) electrostriction displacement changes when a voltage is applied to it. The displacement causes the fibre (FBG) which is bonded to the PZT material to have a resultant change in the wavelength. An optical fibre sensor prototype has been developed and evaluated that measures up to 250 V DC. Simulation using ANSYS software has been used to demonstrate the operational capability of the sensor up to 300kV AC. This sensor overcomes some of the challenges of conventional sensors issues like electromagnetic interference, signal transmission, resolution etc. R BASHOUR 2 A novel optical fibre high voltage based on the Kerr effect has been demonstrated. The The Kerr effect was determined using Optsim (R-Soft) software and Maxwell software was used to model an optical Kerr Cell. Maxwell software is an electromagnetic/electric field software used for simulating, analysing, designing 2D and 3D electromagnetic materials and devices. It uses highly accurate Finite Element techniques to solve time varying, static, frequency domain electric and electromagnetic fields. A Relay Protection System on electrical networks was discussed in detail. Keywords: Fibre Bragg Grating, Fibre Optics Sensors, Piezoelectricity, Kerr effect, Relay Protection Systems.

The properties of two novel random fibre lasers, in which stimulated Brillouin scattering supplies the effective gain mechanism and Rayleigh scattering along the standard telecommunication optical fibre provides random distributed feedback, are characterised. Firstly, ultra-narrow microwave signals with a Dirac delta function profile are successfully created by beating two random-lasing near-Gaussian beams, arising from the synchronization of optical modes from two Stokes signals with random phase accumulated over the ultra-long optical fibre. This finding provides a completely new approach to synthesise high spectral purity microwave signals from Brillouin fibre lasers with randomised feedback. In addition, we also develop a theoretical model of the random fibre Fabry-Pérot resonator based on the fact that the pump depletion effect naturally selects out the effective Rayleigh feedback regions localised in both ends of this long fibre. A narrow random-laser output with the linewidth of ~860 Hz is experimentally demonstrated and is employed to characterise the linewidth of the pump light. Furthermore, the random laser dynamics is studied and one application towards the physical entropy source is eventually achieved.

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