الفهرس Only 14 pages are availabe for public view
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Abstract
The thesis presents a new and simple Ultra-High-Speed,UHS, technique to detect the high frequencies components lini tiated on the power transmission lines and its application on protective relaying area. The suggested technique is based on the sequential overlapping derivative concept for voltage signals. Therefore, the suggested technique is called. (SOD). The thesis uses the information extracted from the mentioned technique to introduce relaying functions such as fault detection, fault direction, fault classification, phase selection and distance measurement. These relaying functions use only the voltage measurement at both ends of the line consequently ; current transformer saturation problem is avoided. The distance measurement and fault direction techniques implement the time instants of fault detection at relaying stations as SOD signals exceed a predetermine threshold limit. The simulation results proved the feasibility of the suggested techniques. The techniques are successfully applied in plain and teed transmission networks. A fault classification and phase selection technique uses the information available in the sequential overlapping derivative, SOD, signals for individual phases and the residual are succeeded to classify the fault type and select the faulted phase. A limited experimental study, using a mathematical transmission model, proved the possibility of extracting the transient components due to faults and abnormal changes on the transmission systems. The main advantages of the suggested relay are ; The relay shows a good stability even under sever conditions such as remote end faults, close up faults, 3 km, high impedance fault up to 2000 Q and low fault inception angles, zero degrees It responds very well concerning dependability, security and sensitivity. Transients initiated due to other conditions such as load switching and line energizing do not cause false operation the relay responses . The relay belongs to adaptive, simple, and ultra-high-speed protecting relaying . Although the fault location calculation is dependent on the propagation speed, the phase signals are used instead of the modal components. In addition, the thesis presents an extension application of the suggested protecti ve technique to the EHV teed transmission lines. Successful experimental implementation for extracting the SOD signal in real time is carried out which comply with the result of the simulation studies. The outlined results through out this thesis demonstrate resounding success for the suggested techniques.