Method for projecting traveling wave of same-tower double-circuit HVDC transmission line

Abstract

The invention discloses a method for projecting traveling wave of a same-tower double-circuit HVDC transmission line. The method includes employing different criteria for and setting the upper and lower layers of pole wires respectively, eliminating outer-zone faults of the upper-layer pole wire through voltage change rate and current direction, eliminating outer-zone faults of the lower-layer pole wire through ground-mode change rate, employing voltage integration ratio to distinguish the fault of the very pole wire, for the upper-layer pole wire, from that of the other pole wire, and employing voltage integration ratio and modulus integration ratio to distinguish the fault of the very pole wire, for the lower-layer pole wire, from that of the other pole wire. The method has the advantage of high sensitivity, less operation burden and short determination time, the information of the very round is needed, communication between different rounds is not required, and influence of transition resistance is minimal. The fault pole wire of a same-tower double-circuit DC transmission line can be rapidly determined, and misjudgement hardly occurs.

Description

technical field [0001] The invention relates to a relay protection technology for high-voltage direct current transmission lines in power systems, in particular to a traveling-wave protection method for double-circuit high-voltage direct current transmission lines on the same tower. A traveling-wave protection scheme for double-circuit HVDC transmission lines on the same tower with different protection criteria satisfying the setting value and realizing reliable protection operation. Background technique [0002] With the continuous development of the grid scale, HVDC transmission systems are more and more widely used in practical projects, and at the same time, double-circuit HVDC transmission systems on the same tower have emerged. Compared with single-circuit line transmission, the DC transmission system adopts the method of erecting double-circuit lines on the same tower, which is more conducive to saving the transmission corridor and improving the power transmission cap...

AI Technical Summary

Problems solved by technology

Traveling wave protection of double-circuit HVDC transmission lines on the same tower also has the problem of poor tolerance to transition resistance

In addition, the double-circuit HVDC transmission line on the same tower has two circuits, and the arrangement of the lines is asymmetrical. Different polar line faults have different coupling amounts on other polar lines. Therefore, the traveling wave characteristics obtained by different line faults are different, and the types of faults are relatively increased. , if the protection criterion of the single-circuit DC transmission line is still used, and the protection is carried out by the change rate and amplitude of the voltage traveling wave or the modulus traveling wave, the protection setting process is more complicated and the reliability is not high

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