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Power transmission line phase-to-phase distance protection section III protection method

A transmission line and phase-to-phase distance technology, applied to emergency protection circuit devices, electrical components, etc., can solve the problems that the impact of impedance distance protection action performance cannot be ignored, hidden dangers of power grid safety, load transfer, etc., to prevent large power flow transfers , enhanced security and stability, and the effect of simple algorithm principle

Inactive Publication Date: 2014-05-14
STATE GRID CORP OF CHINA +2
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AI Technical Summary

Problems solved by technology

[0002] The additional impedance generated by the transition resistance will seriously affect the action performance of the impedance distance protection
If the additional impedance generated by the transition resistance is resistive and inductive, it is easy to cause the impedance distance protection to refuse to operate when there is a phase-to-phase fault in the protection zone; if the additional impedance generated by the transition resistance is resistive and capacitive, it is easy to cause the impedance distance protection to exceed when there is a phase-to-phase fault outside the protection zone
[0003] High / super / extreme voltage AC transmission lines are often also heavy-duty transmission lines. Heavy-load currents will cause the impedance distance protection to malfunction or refuse to operate. The influence of heavy-load currents on the performance of impedance distance protection cannot be ignored.
Under the condition of overload transmission, the line has no faults. The measured impedance of the traditional distance protection will seriously deviate from the actual measured impedance due to the influence of the overload current, which will easily lead to the misoperation of the traditional distance protection, resulting in the expansion of the power grid blackout range, and even causing a large number of load transfers to threaten the normality of the line. operation, causing a huge security risk to the grid security

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  • Power transmission line phase-to-phase distance protection section III protection method

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Embodiment Construction

[0017] The technical solution of the present invention will be further described in detail according to the accompanying drawings.

[0018] Such as figure 1 As shown in the schematic diagram of the line transmission system implementing the method of the present invention, the protection device samples the voltage waveform of the voltage transformer PT and the current waveform of the current transformer CT at the installation place of the transmission line protection to obtain the instantaneous value of voltage and current, and Calculation of Fault Phase-to-Phase Voltage at Transmission Line Protection Installation Using Fourier Algorithm Negative sequence current between fault phases and fault phase-to-phase current Wherein, φφ is AB phase, BC phase or CA phase.

[0019] Protection device calculates arc voltage between phases of transmission line Among them, z1 is the positive sequence impedance of the transmission line per unit length; for the imaginary part of ...

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Abstract

The invention relates to a power transmission line phase-to-phase distance protection section III protection method. The method comprises the steps that a fault phase-to-phase voltage, a fault phase-to-phase current and a fault phase-to-phase negative-sequence current at a power transmission line protective installation position are measured firstly, a phase-to-phase arc voltage at a phase-to-phase short-circuit fault point of the power transmission line is calculated, and then the amplitude of the phase-to-phase arc voltage and a rated voltage amplitude of the power transmission line are utilized to form a power transmission line phase-to-phase short-circuit fault relay protection criterion. According to the power transmission line phase-to-phase distance protection section III protection method, lumped parameters are adopted for modeling, the algorithm principle is simple, programs are implemented easily, the calculation amount is small, and protective action is high in speed. By means of the power transmission line phase-to-phase distance protection section III protection method, the power transmission line phase-to-phase short-circuit fault relay protection criterion is formed by utilizing the amplitude characteristics of the phase-to-phase arc voltage, motion performance is not affected by transition resistance and load current, large-area power outage of a power grid caused by great shift of power grid tidal current due to phase-to-phase distance protection III protection false operations under the condition of overload of the power transmission line is effectively prevented, and operation safety and stability of the power grid are reinforced.

Description

technical field [0001] The invention relates to the technical field of electric power system relay protection, in particular to a protection method for section III of phase-to-phase distance protection of transmission lines. Background technique [0002] The additional impedance generated by the transition resistance will seriously affect the action performance of the impedance distance protection. If the additional impedance generated by the transition resistance is resistive and inductive, it is easy to cause the impedance distance protection to refuse to operate when there is a phase-to-phase fault in the protection zone; if the additional impedance generated by the transition resistance is resistive and capacitive, it is easy to cause the impedance distance protection to exceed when there is a phase-to-phase fault outside the protection zone. [0003] High / super / extreme voltage AC transmission lines are often also heavy-duty transmission lines. Heavy-load currents will c...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H02H7/26
Inventor 林富洪陈文景徐致远李振华林明星
Owner STATE GRID CORP OF CHINA
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