الفهرس 
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Abstract
Trditional methods for measuring high voltages and currents need massive and expensive insulation to protect personnel and equipment, Also, these methods have several disadvantages especially in transient conditions. Therfore, the author has proposed new optical tequniques for measuring voltages and currents of high-voltage transmission lines.
For measuring high voltages optically, a novel techniques has been proposed based on placing a novel kerr-cell, having no electrodes, near the high-voltage conductor. Since this cell is to measure the electric field inside the cell, the relation between the electric field inside the cell and the voltage to be measured must be calculated. Because the cell is surrounded by air and because it is fielled by an optical liquid having permittivity different from that of air, the field calculation was complex. The Charge Simulation Method (73) has been used in calculating electric fields inside a kerr cell for coronating and noncoronating systems. In the case of coronating systems, Poisson`s equationhasbeen solved because of the presence of space charges.
Because the permittivity of the optical liquid filling the cell is different from that of air, a measure of the optical- liquid sensitivity (figure of Merit) has been proposed which results in finding new applications for (Chlorotoluene) to be used in the proposed electrdeless Kerr cell .The figure of merit of chlorotoluene is much higher than that of nitrobenzene which has the highest Kerr constant among the common liquids, even though no Kerr-effect applications for chlorotoluene had been reported in the literature before.
For measuring the Kerr retardation angles, a novel optical system has been employed. This optical system is so sensitive that a 5 mill-degrees has been measured, even though the light source was too noisy.
Experimental models have been built fpor measuring high voltages optically and by a calibrated potential divider. Todiscrepancy between the two measurements was less than 4% which may be controlled to ignoring the fringing effect in calculating the field inside the cell.
This proposed technique is capable of measuring a very wide range of voltages by placing the new Kerr cell at a suitable distance form the high-voltage electrode. The minimum voltage measured was 400 volts,while this technioque is capable of measuring ultra high voltages without limits.
For measuring high currents, a magneto optical technique has been proposed. This technique is based on placing a material, exhibits Faraday effect, near a current carrying conductor.Sincse the Faraday material reflects only the average value of magnetic field intensity inside it, the relation between the field inside the material and current to be measured must be calculated. Because the Faraday material has permeability different from that of air and because the presence of the earth return current, the calculationis complex. Therefor, a novel simulation method has been proposed to solve such systemThis method is based on simulatingthe current carrying conductor, the Faraday material and the earth return current by sets of current filaments which satisfy the boundry condirions of the system. The accuracy of simulation was ranged from 0.1to 1.0 percent according to the value of per eability of the Faraday material.
An experimental model has been built for measuring high currents optically and by a calibrated clamp-ammeter. Also, a current source capable of supplying 350amperes has been built.
The discrepancy between the optical and the clamp-ammeter measurements was less than 1.0 percent.
Although the Faraday material used a free sample of light-density-flint glass having a low Verdet constant, i e. optical sensitiviy, the minimum was 12.5 amperes.