Protecting method for short-circuit between wire coils of parallel reactor of ultrahigh voltage transmission line

A technology of inter-turn short circuit and reactor, which is applied in the direction of automatic disconnection emergency protection device, circuit device, emergency protection circuit device, etc., and can solve problems affecting compensation characteristics, inter-turn fault protection performance defects, and unfavorable protection. , to achieve the effect of improving the sensitivity

Inactive Publication Date: 2005-08-10
TIANJIN UNIV
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Problems solved by technology

However, as an existing technology closest to the present invention, this method has a small zero-sequence component when a slight turn-to-turn fault occurs, so the zero-sequence power direction protection adds compensation characteristics, but the change of the system operation mode will affect The effect of compensation characteristics is not conducive to the use of protective
[0005] Aiming at the deficiencies in the protection performance of current shunt reactors, especially the defects in the protection performance of inter-turn faults, the present invention proposes an inter-turn protection method based on negative sequence power direction

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  • Protecting method for short-circuit between wire coils of parallel reactor of ultrahigh voltage transmission line
  • Protecting method for short-circuit between wire coils of parallel reactor of ultrahigh voltage transmission line
  • Protecting method for short-circuit between wire coils of parallel reactor of ultrahigh voltage transmission line

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Embodiment Construction

[0020] Shunt reactors are generally connected to one or both ends of the ultra-high voltage transmission line in a Y shape. In order to suppress problems such as potential supply current and resonance overvoltage, shunt reactors often have a small reactance at the neutral point. The equivalent circuit of the shunt reactor connected to the ultra-high voltage system is as follows: figure 1 shown. Z in the picture L is the shunt reactor impedance; Z N Small reactance for the neutral point.

[0021] During normal operation, the sequence current relationship is Assuming that there is a turn-to-turn fault in phase A of the shunt reactor, its impedance changes as Z F . According to the symmetrical component method, the fault sequence network diagram of inter-turn short circuit can be calculated as follows: figure 2 shown.

[0022] From the analysis of the sequence network diagram, it can be seen that when there is a slight inter-turn fault, z = ...

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Abstract

Negative sequence voltage and current is calculated from phase voltage and phase current of leading out end at high voltage side of reactor. Based on the calculated value of negative sequence voltage and current, steps of determining short circuit between turns is as follows: when short circuit fault between turns occurs, direction of negative sequence power is determined from phase relation between negative sequence voltage and current; determining whether short circuit fault between turns occurs inside district or outside district. The method increases action sensitivity of protection components, and cancels out characteristics of impedance compensation used in traditional protection in homopolar power direction. The invention protects reactor, determines earth fault, and guarantees not false operation. Theoretical analysis and emulation test prove correctness and validity of the new theory for protecting turns of reactor.

Description

technical field [0001] The invention relates to a protection method for a shunt reactor of a transmission line in a power system, in particular to an inter-turn short-circuit protection method for a shunt reactor of an ultra-high voltage transmission line based on the principle of negative sequence power direction. Background technique [0002] The ground capacitance current of long-distance EHV and UHV transmission lines is very large, which is prone to serious overvoltage problems. The inductance of the shunt reactor can compensate the ground capacitance of the line and weaken the capacitance effect. At the same time, since single-phase reclosing is widely used in ultra-high voltage lines, in order to limit the submerged current and improve the success rate of reclosing, it is often necessary to install shunt reactors with small neutral reactance on ultra-high voltage and above lines. Therefore, as the key equipment of transmission lines, shunt r...

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H02H3/38H02H7/26
Inventor 李永丽李斌
Owner TIANJIN UNIV
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