الفهرس 
SummaryOnly 14 pages are availabe for public view
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Abstract
Some real technical problems, which have badly affect the quality of supply to customers and the coordination of the instantaneous over current. A proposal solution for the magnetizing inrush current problem to the conventional over current relays are used to prevent the over current relay to operate during the distribution transformers are energized. Also, two different solutions in which the instantaneous over current relays should not maloperate due to the d.c component which is associated with the fault current during transient is introduced. A modified computer program for digital over current relays to discriminate between the increase in current as a result of a fault and the increase in current as a result of inrush current, which is based on the 2nd harmonic component, is presented. A new solid state current limiter for power distribution system is proposed. The proposed equipment is insert in the outgoing terminals of a main power transformer, to avoid the replacing of circuit breakers and reducing the damage that may be occurred at the fault point. Also, it is installed either in parallel or in series with the system,. A computer simulation of electric power distribution system based on the Electro Magnetic Transient Program (EMTP) is presented.