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

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...

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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