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A Method for Identifying Internal and External Faults of DC Transmission Line Based on Performance Equation of Smoothing Inductive Components

A technology of direct current transmission lines and inductive components, which is applied in the direction of the fault location, etc., can solve the problems of poor setting of setting values, non-repeatable limitations, and difficulty in capturing traveling wave signals, etc., and achieve excellent reliability and sensitivity of the action, Accelerates the effect of backup protection

Inactive Publication Date: 2011-12-21
KUNMING UNIV OF SCI & TECH
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, since the reliability of the criterion depends on the physical boundary frequency characteristics, there will be a problem that the setting value is not easy to set in practical applications.
The DC traveling wave protection composed of the polarity of the traveling wave head can correctly identify faults inside and outside the zone, but the reliability of the traveling wave protection is limited due to the difficulty of capturing and non-repeatability of the traveling wave signal

Method used

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  • A Method for Identifying Internal and External Faults of DC Transmission Line Based on Performance Equation of Smoothing Inductive Components
  • A Method for Identifying Internal and External Faults of DC Transmission Line Based on Performance Equation of Smoothing Inductive Components
  • A Method for Identifying Internal and External Faults of DC Transmission Line Based on Performance Equation of Smoothing Inductive Components

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0029] Example 1: ±800kV DC transmission line (transmission system structure such as figure 1 ). The transmission capacity is 5000MW, and the reactive power compensation capacity on the rectifier side and the inverter side is 3000Mvar and 3040Mvar; each pole commutation unit is composed of two 12-pulse converters; the DC line side is equipped with a 400mH smoothing reactor; DC The filter is a 12 / 24 / 36 three-tuned filter; the line is a six-split wire, using the J.Marti frequency line model, the line length is 1500km, and the physical boundary of the DC is as figure 1 (b), where, L =400mH, L 1 =39.09mH, L 2 =26.06mH, L 3 =19.545mH, L 4 =34.75mH, C 1 =0.9μF, C 2 =0.9μF, C 3 =1.8μF, C 4 =0.675μF.

[0030] The ground fault of the positive pole of the DC transmission line is 100km from the M terminal, the transition resistance is 10Ω, the time window length is 3ms, and the sampling frequency is 10kHz.

[0031] (1) After the DC line fails, the starting element is started, according to t...

Embodiment 2

[0034] Example 2: The DC transmission line system is the same as Example 1. The smoothing reactor outlet on the rectifier side and the inverter side of the DC line fails at the same time, the transition resistance is 10Ω, the time window length is 3ms, and the sampling frequency is 10kHz.

[0035] After the DC line fails, calculate the analog voltage waveform in the same way as in Example 1. , And its correlation coefficient with the measured voltage waveform to get =- 0.367 =-0.245 <0, judged as a fault outside the area on both sides.

Embodiment 3

[0036] Example 3: The DC transmission line system is the same as Example 1. AC system A phase ground fault (A-G) on the rectifier side of the DC line, the transition resistance is 10Ω, the time window length is 3ms, and the sampling frequency is 10kHz.

[0037] After the DC line fails, calculate the analog voltage waveform in the same way as in Example 1. , And its correlation coefficient with the measured voltage waveform to get =- 0.1842 =0.9657﹥0, judged as a fault outside the M-side zone.

[0038] The principle of the present invention is:

[0039] 1. Short window description of the fault characteristics inside and outside the DC line

[0040] (1) Fault in the DC line area

[0041] Assuming that the positive line has an area fault, the additional network of the fault component is as Figure 4 Shown. In the figure, ( Z c , γ ) Is expressed as a distributed parameter transmission line, measuring current i M , i N It uses the pole bus differential protection to measure the curre...

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Abstract

The invention provides a method for simulating and identifying internal and external faults of a direct current transmission line based on the performance equation of a smoothing inductance element, and belongs to the technical field of identification and protection of direct current transmission line internal and external faults. Using the short data window, the voltage and current fault components on both sides of the DC transmission line satisfy the performance equation (VCR) of the smoothing inductance element when an internal fault occurs on the DC transmission line, but the voltage and current fault components on the fault side do not satisfy the flat wave Based on the principle of VCR of inductive components, a post-test simulation time-domain method for fault identification inside and outside the zone focusing on the current response solution is proposed. Using the measured current on both sides of the line, the smoothing inductance element VCR simulates and calculates the voltage on both sides, and then compares the correlation with the measured voltage waveform to judge and identify faults inside and outside the DC transmission line. It has the advantages of sensitive identification of faults in the area and reliable identification of faults outside the area, and is suitable for popularization and use in DC transmission line systems.

Description

technical field [0001] The invention relates to the technical field of electric power system relay protection, in particular to a method for simulating and identifying internal and external faults of DC transmission lines after measurement based on the performance equation of a smoothing inductance element. Background technique [0002] The existing DC line protection uses the traveling wave protection based on the change rate criterion as the main protection, and the current differential protection as the backup protection. The traveling wave protection with du / dt as the core can not only be used as a fault start criterion, but also can correctly identify faults inside and outside the zone, and has strong practicability. However, if a high-resistance grounding fault occurs on the DC line, the amplitude of the voltage traveling wave and the steepness of the wave head will decrease, which will easily cause the protection to refuse to operate. Differential protection is used ...

Claims

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Application Information

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IPC IPC(8): G01R31/08
Inventor 束洪春何利君田鑫萃曾芳宋建常勇郭福生胡浩王家勇
Owner KUNMING UNIV OF SCI & TECH
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