High-voltage direct-current transmission line calculation model based on distributed resistance parameters

Abstract

The invention discloses a high-voltage direct-current transmission line calculation model based on distributed resistance parameters. The method comprises the steps of (1) acquiring a fault voltage signal and a current signal; (2) carrying out decoupling to obtain aerial mode components; (3) calculating voltage and current aerial mode components of a direct-current transmission line along the lineby utilizing a distributed parameter line model based on distributed resistance; (4) calculating a reverse traveling wave current of the direct-current transmission line along the line; and (5) calculating a modulus maximum value of the reverse traveling wave current by adopting stationary wavelet transform. According to the method, after voltage and current values of measuring points at the twoends of the line are extracted, voltage and current aerial mode component values of the direct-current transmission line along the line are calculated by utilizing the line model based on the distributed resistance; then according to the characteristics that a first reverse traveling wave is not reflected yet, the influence of frequency change of a reflection coefficient is avoided and fault features are obvious, a reverse traveling wave current value of the direct-current transmission line along the line is calculated; and finally, the modulus maximum value of the reverse traveling wave current is calculated through the stationary wavelet transform, so that the accuracy of the transmission line calculation model is improved.

Description

technical field [0001] The invention relates to the technical field of power systems, in particular to a high-voltage direct current transmission line calculation model based on distributed resistance parameters. Background technique [0002] In recent years, my country's high-voltage direct current transmission projects have been put into operation one after another. According to the plan, there will be 36 direct current projects by 2020, of which there are as many as 16 direct current projects with a voltage level of ±800kV and above. The safe and stable operation of HVDC transmission projects is of great significance to ensure the safety and reliability of the entire power grid. When a fault occurs on a high-voltage direct current transmission line, it is necessary to quickly and accurately find out the cause of the fault and determine the location of the fault. [0003] Since the HVDC overhead transmission line stretches for hundreds or even thousands of kilometers, and...

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Problems solved by technology

[0005] The purpose of the present invention is to solve the problem that the inaccurate calculation model of the current high-voltage direct current transmission line leads to the increase of the ranging error, and proposes a calculation model of the high-voltage direct current transmission line based on distributed resistance parameters, and extracts the voltage and current of the measurement points at both ends of the line After the value is calculated, the voltage and current values ​​along the DC transmission line are calculated by using the line model that takes the distributed resistance into account, and then according to the fact that the first reverse traveling wave has not yet reflected after the fault, it is not affected by the frequency change of the reflection coefficient, and the fault characteristics are obvious. Calculate the reverse traveling wave current value along the DC transmission line, and finally calculate the modulus maximum value of the reverse traveling wave current through the stationary wavelet transform to improve the accuracy of the transmission line calculation model

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