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Identification method for faults in and out of area of high voltage direct current (HVDC) transmission line based on multi-fractal spectrum

A multi-fractal spectrum, high-voltage DC technology, applied in fault locations, information technology support systems, etc., can solve problems such as noise interference, refusal of traveling wave protection devices, and reduction in the rate of change of traveling wave protection voltages.

Active Publication Date: 2015-01-28
KUNMING UNIV OF SCI & TECH
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

However, relevant data show that the currently used DC line traveling wave protection technology (mainly provided by ABB and SIEMENS) has problems such as easy misoperation, interference by noise, or influence by transition resistance to varying degrees. When a high-impedance fault occurs, the voltage change rate of the traveling wave protection decreases, which sometimes leads to the refusal of the traveling wave protection device

Method used

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  • Identification method for faults in and out of area of high voltage direct current (HVDC) transmission line based on multi-fractal spectrum
  • Identification method for faults in and out of area of high voltage direct current (HVDC) transmission line based on multi-fractal spectrum
  • Identification method for faults in and out of area of high voltage direct current (HVDC) transmission line based on multi-fractal spectrum

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Experimental program
Comparison scheme
Effect test

Embodiment 1

[0049] Embodiment 1: as figure 1 As shown, this multi-fractal spectrum-based fault identification method for high-voltage direct current transmission lines inside and outside the area is used in the Yunguang ±800kV direct current transmission system. The power transmission capacity of the system is 5000MW, and the reactive power compensation capacity of the rectification side and the inverter side are 3000Mvar and 3040Mvar respectively; each pole commutation unit is composed of two 12-pulse converters in series, and the DC transmission line is a six-split conductor with a total length of Take it as 1500km, using the J.R.Marti frequency correlation model; 400mH smoothing reactors are installed on both sides of the line; F 2 , F 3 is an out-of-area fault, F 1 , F 4 is the fault in the area, and M is the place where the protection is installed.

[0050] Such as figure 2 As shown, the physical boundaries of the DC transmission system are composed of smoothing reactors and D...

Embodiment 2

[0070] Embodiment 2: as figure 1 , 2 As shown, this multi-fractal spectrum-based fault identification method for high-voltage direct current transmission lines inside and outside the area is carried out in the Yunguang ±800kV direct current transmission system, and the structure and related parameters of the transmission system are the same as those in embodiment 1.

[0071] At a distance of 150km from the protection installation, a positive ground fault occurs in 0.505s, and the transition resistance is 10Ω. By the same method as in Example 1, the same sampling frequency 、 The length of the sampling time window and the length of the sampling sequence to find the fault component of the line-mode voltage waveform like Figure 5 As shown, the singularity index multifractal spectrum of Such as Figure 7 shown; get the minimum value of the singularity index =0.7902, maximum value =1.3230, singularity exponent growth rate k =0.6743.

[0072] The resulting singularit...

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Abstract

The invention relates to an identification method for faults in and out of an area of a high voltage direct current (HVDC) transmission line based on a multi-fractal spectrum, which belongs to the technical field of relay protection of a power system. When a fault occurs in a direct current circuit, after a protective element is started, according to two-electrode direct voltage detected at a protective installation position, aerial mode voltage is obtained by utilizing the phase mode conversion theory. Fault component of the aerial mode voltage is obtained according to the superposition principle, probability density at different levels is obtained through the side length of a transform box, then partition function and quality factor are obtained, finally singularity exponent and growth rate k of the singularity exponent are obtained, and then faults in and out of the area are judged according to the k value. Sampling frequency is 20 kHz, time window is 1ms, the required data length is short, and effect of a control system is avoided. The identification method is capable of correctly identifying various types of faults within the range of the whole line and high in tolerance property for transition resistance, is not affected by interference and has high practical applicability.

Description

technical field [0001] The invention relates to a method for identifying internal and external faults of a high-voltage direct current transmission line, in particular to a method for identifying internal and external faults of a high-voltage direct current transmission line based on a multi-fractal spectrum, which belongs to the technical field of electric system relay protection. Background technique [0002] The high-voltage direct current transmission line has a large transmission power. After the line fails, the line protection device must remove the fault as quickly as possible, otherwise it will cause a great impact on the entire system and pose a threat to the safe and stable operation of the system. General power frequency protection operates slowly and takes a long time, which is difficult to meet the requirements of DC transmission line protection. At present, traveling wave protection technology is widely used in the world as the main protection of HVDC transmiss...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): G01R31/08
CPCY04S10/522Y04S10/52
Inventor 束洪春安娜董俊
Owner KUNMING UNIV OF SCI & TECH
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