چكيده به لاتين
Abstract:
In this thesis, a comprehensive algorithm including fault detection, faulted phase selection, and full protection of transmission lines with proper discrimination between external and internal faults has been presented.
The proposed algorithm is based on the calculation of energy in the high-frequency components of the voltage signal. This scheme can discriminate between external and internal faults based on fault-initiated transients, considering the high-stop filtering property of busbars through modelling their stray capacitances and employing three processing tools including Wavelet transform, TT-transform and Mathematical Morphology Gradient for extracting transient components.
The proposed algorithm keeps its high accuracy for all fault inception angle (even near the zero angle), the fault resistance up to 200 ohms and the change of operating points (change the direction and magnitude of transitional power) and is very fast as it needs only 3 samples after fault occurrence. The algorithm is one-sided and has low computational burden and it can be used for compact line, as well.
The proposed algorithm not only has been investigated for voltage signals as inputs, but also has been evaluated for current signals and the results show that the proposed algorithm has the correct performance in both situations.
Simulation results of Anjirak-RudShur 400kV transmission line in the EMTP software have shown that the performance of the proposed algorithm in both dependability and security aspects shows high accuracy.
Keywords: High-frequency components, transmission line protection, compact transmission lines, fault location, faulted phase selection.
