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Full-line quick-acting protection method in which T-type transmission grid single-end transient state quantity S-transform is utilized

A full-line quick-acting, transient technology, applied in emergency protection circuit devices, electrical components, fault locations, etc., can solve the problems of protection quick-acting decline, inability to adjust time-frequency resolution, etc., to achieve reliable and easy calculation results. Simple effects of commissioning and maintenance, protection concepts and protection devices

Active Publication Date: 2014-04-30
KUNMING UNIV OF SCI & TECH
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

Compared with traveling wave protection, the quick action of this kind of protection formed by high-frequency noise in the window for a period of time after the fault is lower, but compared with the traditional power frequency line protection, its quick action is still greatly improved.
When identifying faults inside and outside the zone, it is necessary to combine signal processing methods to extract the required frequency band components to characterize the fault characteristics contained in it, and the S transform is an excellent idea that combines continuous wavelet transform and short-time Fourier transform and has been further developed. , it overcomes the short-term Fourier transform window shape is fixed, the defect of time-frequency resolution can not be adjusted

Method used

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  • Full-line quick-acting protection method in which T-type transmission grid single-end transient state quantity S-transform is utilized
  • Full-line quick-acting protection method in which T-type transmission grid single-end transient state quantity S-transform is utilized
  • Full-line quick-acting protection method in which T-type transmission grid single-end transient state quantity S-transform is utilized

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0034] Embodiment 1: as figure 1 The T-shaped line model of the 500kV transmission line shown, the line length l MN =200km, l PM =70km, l NQ =50km, l TO =40km. Protection relay R 1 Installed on the M side of the line being studied. C E Indicates the stray capacitance of the bus to ground, the value is 0.1μF. An AG fault occurs at a distance of 60km from the M terminal in the MT section, and the fault angle is 90°. The phase-to-mode transformation of the fault current is carried out to obtain the line-mode current transient quantity of the fault phase, such as figure 2 Shown; S-transform the linear-mode current transient; use the S-transform matrix to extract high-frequency components I H and low frequency components I L , and construct the high-frequency transient energy according to equations (1) and (2) respectively E H and low frequency transient energy E L ,Such as image 3 Shown; according to the formula (3) to find the energy ratio lambda ( n ),S...

Embodiment 2

[0035] Embodiment 2: as figure 1 The T-shaped line model of the 500kV transmission line shown, the line length l MN =200km, l PM =70km, l NQ =50km, l TO =40km. Protection relay R 1 Installed on the M side of the line being studied. C E Indicates the stray capacitance of the bus to ground, the value is 0.1μF. An AG fault occurs at 60km from the M terminal in the MT section, and the fault angle is 45°. The phase-to-mode transformation of the fault current is carried out to obtain the line-mode current transient quantity of the fault phase, such as Figure 5 Shown; S-transform the linear-mode current transient; use the S-transform matrix to extract high-frequency components I H and low frequency components I L , and construct the high-frequency transient energy according to equations (1) and (2) respectively E H and low frequency transient energy E L ,Such as Image 6 Shown; according to the formula (3) to find the energy ratio lambda ( n ),Such as Figur...

Embodiment 3

[0036] Embodiment 3: as figure 1 The T-shaped line model of the 500kV transmission line shown, the line length l MN =200km, l PM =70km, l NQ =50km, l TO =40km. Protection relay R 1 Installed on the M side of the line being studied. C E Indicates the stray capacitance of the bus to ground, the value is 0.1μF. An AG fault occurs at a distance of 40km from the N terminal in the NQ section, and the fault angle is 90°. The phase-to-mode transformation of the fault current is carried out to obtain the line-mode current transient quantity of the fault phase, such as Figure 8 Shown; S-transform the linear-mode current transient; use the S-transform matrix to extract high-frequency components I H and low frequency components I L , and construct the high-frequency transient energy according to equations (1) and (2) respectively E H and low frequency transient energy E L ,Such as Figure 9 Shown; according to the formula (3) to find the energy ratio lambda ( n ),...

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Abstract

The invention relates to a full-line quick-acting protection method in which the T-type transmission grid single-end transient state quantity S-transform is utilized, and belongs to the technical field of electric power system relay protection. When an electric transmission line breaks down, the S-transform is carried out on the line module current transient state quantity which comprises the fault phase and is obtained by a measuring end to obtain a complex-time-frequency matrix, module values of all elements in the matrix are solved to obtain a modular matrix, a high-frequency component IH and a low-frequency component IL are constructed respectively through the modular matrix, the high-frequency transient state energy EH and the low-frequency transient state energy EL are calculated respectively, and the interior fault and the exterior fault of a line to be protected is judged according to the specific value lambda of EH to EL; after the fault is started by 1 ms, lambda in a time window is larger than or equal to 1, the area interior fault is judged, or otherwise, the area exterior fault is judged. The protection for the T-type transmission grid line can be achieved only through the single-end transient state quantity, communication equipment and communication channels are not needed, a protection scheme and a protection device are simple, and debugging and maintaining are easy.

Description

technical field [0001] The invention relates to a full-line rapid protection method for a single-end transient quantity of a T-type transmission network using S transformation, and belongs to the technical field of electric power system relay protection. Background technique [0002] In high-voltage transmission lines, T-connection is a common line connection method. This method is simple in wiring, fast in construction speed and can effectively reduce equipment investment and save land for transmission corridors. But at the same time, the line generally has the characteristics of high transmission power and heavy load. Once the line fails, it may cause large-scale power outages. Therefore, when a fault occurs on a T-shaped line, it is more important to perform fast and effective protection actions. [0003] In the 1990s, A.T.Johns and Z.Q.BO of the University of Bath pioneered the principle of non-channel transient protection. The non-channel transient protection of trans...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H02H7/26G01R31/08
Inventor 束洪春郑韵如高利曹璞璘
Owner KUNMING UNIV OF SCI & TECH