Single-phase permanent fault recognition method for extra-high voltage AC transmission line

A permanent fault, transmission line technology, applied in the direction of the fault location, can solve the problem of destroying the stability of the system

Active Publication Date: 2011-05-18
KUNMING UNIV OF SCI & TECH
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  • Description
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  • Application Information

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Problems solved by technology

While adaptive reclosing brings benefits to the power system, there are also some disadvantages, which have brought adverse effects on the power system. The main problem is that the adaptive reclosing recloses on a permanent fault, causing the power system to suffer a greater impact The influence of the current, destabilizing the system

Method used

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  • Single-phase permanent fault recognition method for extra-high voltage AC transmission line
  • Single-phase permanent fault recognition method for extra-high voltage AC transmission line
  • Single-phase permanent fault recognition method for extra-high voltage AC transmission line

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Embodiment Construction

[0069] Such as Figure 4 The system shown is 100km away from the protection installation, and a phase A ground fault occurs in 0.54s; the faults are simulated for transient faults and permanent faults respectively, and the time window length is selected to be 18ms after the fault, and the sampling frequency is 10kHz.

[0070] (1) After the AC line with shunt reactor fails, the measured recovery voltage value of the fault phase at the protection installation is u f ;

[0071] (2) For AC recovery voltage u f S-transformation is carried out, the sampling frequency is 10kHz, the length of the sampling sequence is 1800, and a complex matrix of 901×1800 is obtained by S-transformation

[0072] X [ n ] = 1 N Σ k = 0 N - 1 x [ k ] e ...

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Abstract

The invention relates to a single-phase permanent fault recognition method for an extra-high voltage AC transmission line using S transform energy. The method comprises the following steps: after fault occurs to an AC line, selecting a disperse voltage signal of which the recovery voltage sampling sequence length is 1,800 after the fault, and performing S transform to obtain a 901*1,800 time frequency complex matrix; and operating modulus of each element in the complex matrix to obtain the energy value under each frequency point. As too many frequency ranges are not good for recognition, every 9 rows from the 2nd row to the 901st row to obtain a 101*1 matrix, the 901 frequency ranges are integrated into 100 frequency ranges, and the frequency of each frequency range is 50 Hz. The single-phase permanent fault is judged according to the size of the first frequency range, namely the 50 Hz frequency range. A large number of simulation results indicate that the effect of the method is good.

Description

technical field [0001] The invention relates to the technical field of electric power system relay protection, in particular to a method for identifying single-phase permanent faults of ultra-high voltage AC transmission lines using S-transformed energy. Background technique [0002] In the power system, the transmission line is an important link in the power system, which is most significantly affected by natural conditions. According to operating experience, more than 70% of the faults are single-phase grounding short circuits on high-voltage overhead lines in large grounding current systems above 110kV , and more than 80% of them are transient faults. While the adaptive recloser brings benefits to the power system, it also has some disadvantages, which have brought adverse effects on the power system. The main problem is that the adaptive recloser overlaps with a permanent fault, which makes the power system suffer a greater impact The influence of the current will destr...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): G01R31/08
Inventor 束洪春刘超田鑫萃刘可真张广斌孙士云
Owner KUNMING UNIV OF SCI & TECH
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