Current and voltage measurement for high voltage equipments by electro - optic methods

In power systems high voltage is measured by electromagnetic voltage transformers, and high current is measured by current transformers. Increasing demand of high capacity of electrical power systems has created higher isolation levels on these devices in recent years. Thus, size of voltage and current transformer has increased. Main disadvantages of conventional current and voltage transformers are; insulation cost, size, weight, poor frequency response, signal distortion on the network, hysteresis losses, partial discharge and vulnerability to magnetic saturation effects. Recent improvements on measurement techniques increase the usage of optical methods. The advantages of electro-optical methods are; their dielectric structure, very small sizes and lightness, linear response at wide frequency range. Also, they are non corrupted by electro-magnetic interference. Therefore, they have been an alternative solution of above mentioned problems. In electro-optic field, Pockels and Kerr effects are widely used for voltage measurement, and Faraday effect is widely used for current measurement. In this study, beside BGO (Bismuth Germanium Oxide) and BSO (Bismuth Silicon Oxide) that are used for sensor body, optical fiber's behavior and response toIV magnetic and electric field has been inspected by obtained theoretical and experimental results. Interferometer measurement techniques have been examined and a new sensing system is constructed. By using this interferometer set-up, AC and DC leakage currents have been measured in the range of 10-100 pA and 35-50 mA respectively. Science Code : 608.02.07 Key Words : Optical current sensors, Current measurement, Optical fibers, Interferometers Page Number : 121 Adviser : Prof. Dr. M. Cengiz TAPLAMACIO?LU