A new faultlocationalgorithm for double-circuit transmission lines with availability of complete measurements from two anti-parallel end of the line is presented. Sequence voltage and current phasors from these ends...
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A new faultlocationalgorithm for double-circuit transmission lines with availability of complete measurements from two anti-parallel end of the line is presented. Sequence voltage and current phasors from these ends are taken as inputs and no synchronisation between them is needed. Using the pre-fault data, the synchronisation angles between measurements at the reference and the anti-parallel ends are obtained. Using the fault data, the faulted circuit is determined and the sequence voltages and currents at the fault point are calculated as a function of the fault distance. Finally, using the fault boundary conditions that exist for a given fault type, the faultlocation is derived and solved by an iterative method. Owing to zero-sequence mutual coupling, it is not straightforward to express the zero-sequence voltage and current at the fault point as a function of the zero-sequence voltages and currents at the two measuring ends and the distance to fault. To overcome this problem, a modal transformation matrix is introduced to obtain the modal networks, which are decoupled and can be analysed independently. Based on distributed parameter line model, the proposed algorithm fully considers the effects of shunt capacitances and thus achieves superior locating accuracy, especially for long lines. Mutual coupling between circuits, source impedances and fault resistance do not influence the locating accuracy of the algorithm. The simulation results using ATP-EMTP and MATLAB demonstrate the effectiveness and accuracy of the proposed algorithm.
precisefaultlocation (FL) is definitely important for fast fault clearance and restoration of energy transmission. The single-terminal FL is mostly met in applications because of its easy implementation, but the acc...
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precisefaultlocation (FL) is definitely important for fast fault clearance and restoration of energy transmission. The single-terminal FL is mostly met in applications because of its easy implementation, but the accuracies of all-type impedance FL algorithms are not good because of the effects of fault resistance and variation of an opposite terminal equivalent system impedance. The recently developed and assembled FL algorithm presented in this study, combining the stability of the impedance FL and precision of the travelling waves FL, is an expected good solution. However, the key point to achieve accurate FL is to naturally couple these two algorithms. As is known, the distributed parameters model is also the research base of these two algorithms. Hence, the impedance FL algorithm in line with distributed parameters is proposed in this study. It is achieved on the discovery that the negative sequence current at relay location maintains precisely the same phase to the voltage at fault point. The proposed algorithm is immune to shunt capacitance because of modelling with distributed parameters, and is not disturbed by ground resistance when calculated at zero-crossing moment of voltage at fault point. Simulations and tests prove its good performance.
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