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Triangular looped network transient state unit protecting method based on direction traveling wave integral comparison principles

A directional traveling wave and triangular technology, applied in the direction of emergency protection circuit devices, electrical components, fault locations, etc., can solve problems such as the influence of current transformer saturation and achieve high reliability

Inactive Publication Date: 2014-12-10
KUNMING UNIV OF SCI & TECH
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

[0004] The technical problem to be solved in the present invention is based on the direction protection of traveling wave amplitude comparison, using the ratio of forward traveling wave and reverse traveling wave amplitude to form a criterion, and proposes a triangular ring based on the principle of directional traveling wave integral comparison The network transient unit protection method overcomes the shortcomings of the traditional power frequency protection being affected by the distributed capacitance of the line and the saturation of the current transformer

Method used

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  • Triangular looped network transient state unit protecting method based on direction traveling wave integral comparison principles
  • Triangular looped network transient state unit protecting method based on direction traveling wave integral comparison principles
  • Triangular looped network transient state unit protecting method based on direction traveling wave integral comparison principles

Examples

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Effect test

Embodiment 1

[0045] Example 1: Example 1: In figure 1 In the simulation system shown, the lengths of the PM, MN, NQ and QM lines are 100km, 100km, 70km and 80km respectively. It is stipulated that the positive current direction of each protection is that the busbar points to the line. Assume that the fault is located in the MQ branch, 20km away from the M terminal, and the transition resistance is 10Ω.

[0046] A. Set the sampling rate of the traveling wave transient signal to 20kHz. define t 0 is the moment when the first wave arrives at the measurement end, l min It is the shortest healthy outgoing line at the measuring end. In the triangular ring network line, the three terminals are defined as M terminal, N terminal and Q terminal, and the direction relays at the two ends of M and N are respectively R 1 , R 2 ; The direction relays at both ends of N and Q are respectively R 3 , R 4 ; The direction relays at both ends of Q and M are respectively R 5 , R 6 . at [t 0 ,t 0 +2l...

Embodiment 2

[0058] Example 2: In figure 1 In the simulation system shown, it is assumed that the fault is located in the MN branch, 10km away from the M terminal, the transition resistance is 10Ω, and the sampling frequency is 20kHz.

[0059] Calculate the direction relay R of each end in the triangular ring network by the method of embodiment 1 1 ~R 6 The absolute value of the forward traveling wave and the absolute value of the reverse traveling wave, the result is Figure 8 ~ Figure 13 . Recalculate the direction relay R 1 ~R 6 The integral value of the forward and reverse traveling wave amplitudes at the discretized measuring end, and then calculate the direction relay R at each end in the triangular ring network 1 ~R 6 lambda ∑ value.

[0060] The calculation result is, λ Σ R 1 = 0.5263 , λ Σ ...

Embodiment 3

[0061] Example 3: In figure 1 In the simulation system shown, it is assumed that the fault is located on the line PM, 50km away from the M terminal, the transition resistance is 10Ω, and the sampling frequency is 20kHz.

[0062] Calculate the direction relay R of each end in the triangular ring network by the method of embodiment 1 1 ~R 6 The absolute value of the forward traveling wave and the absolute value of the reverse traveling wave, the result is Figure 14 ~ Figure 19 . Recalculate the direction relay R 1 ~R 6 The integral value of the forward and reverse traveling wave amplitudes at the discretized measuring end, and then calculate the direction relay R at each end in the triangular ring network 1 ~R 6 lambda ∑ value.

[0063] The calculation result is, λ Σ R 1 = 2.2122 , satisfies lambda ∑ >λ ∑set , λ...

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Abstract

The invention relates to a triangular looped network transient state unit protecting method based on direction traveling wave integral comparison principles and belongs to the technical field of power system relay protection. The method includes: the direction pilot protection of each circuit of a triangular looped network is regarded as a to-be-protected unit; after a fault occurs, the direction element at the circuit measuring end in a fixed time window is used to obtain the amplitude integral ratio lambda of forward traveling waves to reverse traveling waves so as to judge fault direction; if the ratio is smaller or equal to a set threshold lambda sigma set, the fault is judged as the forward fault, and if the ratio is larger than the set threshold lambda sigma set, and the fault is judged as the reverse fault. When the direction elements at two ends of a branch are judged as forward faults, the fault is located on the branch, and the fault occurs inside the protecting area of the triangular looped network; or else the fault occurs outside the triangular looped network. A large amount of simulation experiments indicate that the method is good in effect.

Description

technical field [0001] The invention relates to a protection method for a triangular ring network transient quantity unit based on the principle of directional traveling wave integral comparison, and belongs to the technical field of electric power system relay protection. Background technique [0002] With the continuous construction of ultra-high voltage and ultra-high voltage transmission lines, the continuous operation of large-capacity units, and the interconnection of the power grid, these have put forward higher requirements for the relay protection of the power system. After the line fails, the fault can be quickly and reliably cleared. It is an effective measure to enhance the power transmission capacity of the line and improve the transient stability of the power grid. However, the traditional relay protection based on power frequency has gradually shown its weakness that it cannot quickly detect faults. Traveling wave protection, which uses traveling waves genera...

Claims

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Application Information

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IPC IPC(8): H02H7/28G01R31/08
Inventor 束洪春李嫣然高利
Owner KUNMING UNIV OF SCI & TECH