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 direct current technology, applied in the direction of fault location, information technology support system, etc., can solve problems such as easy misoperation, refusal of traveling wave protection device, and reduced rate of change of traveling wave protection voltage

Active Publication Date: 2012-06-20
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

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0049] Example 1: Such as figure 1 As shown, the multifractal spectrum-based HVDC transmission line fault identification method inside and outside the area is used in the Yunguang ±800kV HVDC transmission system. The power transmission capacity of the system is 5000MW, and the reactive power compensation capacity of the rectifier side and the inverter side are respectively 3000Mvar and 3040Mvar; each pole converter unit is composed of two 12-pulse converters in series, and the DC transmission line is a six-split conductor with a full length Take 1500km, using JRMarti frequency correlation model; 400mH smoothing reactors are installed on both sides of the line; F 2 , F 3 Is an outside fault, F 1 , F 4 It is an area fault, and M is the protection installation location.

[0050] Such as figure 2 As shown, the physical boundary of this DC transmission system is composed of smoothing reactor and DC filter. among them: U 1 Is the transient voltage outside the area, U 2 for U 1 The vo...

Embodiment 2

[0070] Example 2: Such as figure 1 , 2 As shown, the multifractal spectrum-based HVDC transmission line fault identification method inside and outside the area is carried out in the Yunguang ±800kV HVDC transmission system, and the transmission system structure and related parameters are the same as in Embodiment 1.

[0071] A positive grounding fault occurred at a distance of 150km from the protection installation location, 0.505s, and the transition resistance was 10Ω. According to the same method in Example 1, the same sampling frequency 、 Sampling time window length and sampling sequence length to find the fault component of the line mode voltage The waveform is like Figure 5 As shown, the singularity index Multifractal spectrum Such as Figure 7 Shown; get the minimum value of the singularity index =0.7902, maximum =1.3230, the singularity exponential growth rate k =0.6743.

[0072] Singularity exponential growth rate k =0.6743 The value is low, which satisfies the crite...

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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, and belongs to the technical field of power system relay protection. Background technique [0002] HVDC transmission lines have 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. The general power frequency protection has a slow action speed and a long time consuming, and it is difficult to meet the requirements of DC transmission line protection. Currently, traveling wave protection technology is widely used in the world as the main protection of HVDC transmission lines. Its single...

Claims

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Application Information

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Patent Type & Authority Applications(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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