CN103296651B - The line inter-phase fault distance protection method of overload faulty action preventing and resistance to high resistant - Google Patents

Abstract

The invention discloses the line inter-phase fault distance protection method of a kind of overload faulty action preventing and resistance to high resistant.First the inventive method utilizes the fault voltage between phases of line protection installation place, between fault three-phase current and fault phase, negative-sequence current computing electric power line protection seting scope place is to the circuit distance of phase fault point, then judge whether line protection setting range place is greater than zero to the circuit distance of phase fault point, if line protection setting range place is greater than zero to the circuit distance of phase fault point, then judge that phase fault point is positioned within line protection setting range, send action trip signal, the circuit breaker at tripping transmission line two ends.The inventive method principle eliminates the impact of transition resistance on Perfomance of protective relaying, there is the ability of very strong anti-transition resistance impact.<!--1-->

Description

The line inter-phase fault distance protection method of overload faulty action preventing and resistance to high resistant

Technical field

The present invention relates to Relay Protection Technology in Power System field, specifically relate to the line inter-phase fault distance protection method of a kind of overload faulty action preventing and resistance to high resistant.

Background technology

Distance protection due to by power system operation mode and structural change little, moment selectively can excise transmission line various fault, in power system transmission line protection, obtain extensive use.On ultra-high-tension power transmission line, distance protection is used as transmission line main protection, and on ultra-high/extra-high voltage transmission line of alternation current, distance protection is used as transmission line backup protection.The distance protection of current power system transmission line extensive use mainly comprises the protection of power frequency variation distance and impedance distance protection.

The protection of power frequency variation distance forms distance protection by reaction operating voltage amplitude Sudden Changing Rate, and the method has affects the advantages such as little and anti-transition resistance ability is strong by power system operation mode.But the operating voltage amplitude Sudden Changing Rate adopted due to the method only exists at the fault initial stage, the backup protection of ultra-high/extra-high voltage transmission line of alternation current cannot be used as.

Impedance distance protection is positioned at protection zone according to measurement impedance size faults distance length to distinguish fault point or is positioned at outside protection zone.Impedance distance protection due to by power system operation mode and structural change little, the electric parameters for computation and measurement impedance is total failure component, is applicable to whole failure process.Therefore, impedance distance protection both can be used for ultra-high-tension power transmission line main protection, also can be used as the backup protection of ultra-high/extra-high voltage transmission line of alternation current.

But impedance distance protection performance affects seriously by transition resistance, if main manifestations is additional impedance that transition resistance produces is resistance sense impedance distance protection tripping when easily causing line protection troubles inside the sample space; If the additional impedance that transition resistance produces be capacitance-resistance when easily causing line protection external area error, impedance distance protection action generation surmounts.

Super/extreme pressure transmission line of alternation current is also often heavy load transmission line, heavy load electric current can make impedance distance protection malfunction or tripping, and the impact of heavy load electric current on impedance distance protection performance can not be ignored.Transmission line fault-free in overload transmission of electricity situation; the measurement impedance of traditional distance protection is owing to affecting meeting substantial deviation actual measurement impedance by overload electric current; easily cause traditional distance protection misoperation and cause grid power blackout expanded range; even cause the large transfer of load to threaten other transmission lines normally to run, bring huge potential safety hazard to power grid security.

Summary of the invention

The object of the invention is to the deficiency overcoming prior art existence, the line inter-phase fault distance protection method of a kind of overload faulty action preventing and resistance to high resistant is provided.

The line inter-phase fault distance protection method of overload faulty action preventing and resistance to high resistant, is characterized in that, comprises following sequential steps:

(1) the fault voltage between phases of protector measuring line protection installation place , fault three-phase current and negative-sequence current between fault phase , as input variable; Wherein, φ φ=AB, BC, CA phase;

(2) protective device computing electric power line protection seting scope place is to the circuit distance, delta x of phase fault point:

$\mathrm{\&Delta;x}=\left|\frac{{\stackrel{.}{U}}_{\mathrm{\&phi;\&phi;}}-z_1{\stackrel{.}{I}}_{\mathrm{\&phi;\&phi;}}{x}_{\mathrm{set}}}{z_1{\stackrel{.}{I}}_{\mathrm{\&phi;\&phi;}}\sin (\mathrm{\&beta;}+\mathrm{\&gamma;})}\right|\sin \mathrm{\&alpha;}$

Wherein, z ₁for unit length electric transmission line positive sequence impedance; x _setfor line protection setting range; β=Arg (z ₁) be unit length electric transmission line positive sequence impedance z ₁phase angle; for leading angle; for leading angle; φ φ=AB, BC, CA phase;

(3) protective device judges whether line protection setting range place is greater than zero to the circuit distance, delta x of phase fault point, if line protection setting range place is greater than zero to the circuit distance, delta x of phase fault point, then judge that phase fault point is positioned within line protection setting range, protective device sends action trip signal, the circuit breaker at tripping transmission line two ends; Otherwise if line protection setting range place is less than zero to the circuit distance, delta x of phase fault point, then judge that phase fault point is positioned at outside line protection setting range, protective device sends block signal.

The present invention compared with prior art, has following positive achievement:

The inventive method first computing electric power line protection seting scope place to the circuit distance of phase fault point; then judge whether line protection setting range place is greater than zero to the circuit distance of phase fault point; if line protection setting range place is greater than zero to the circuit distance of phase fault point; then judge that phase fault point is positioned within line protection setting range; send action trip signal, the circuit breaker at tripping transmission line two ends.The inventive method principle eliminates the impact of transition resistance on Perfomance of protective relaying, there is the ability of very strong anti-transition resistance impact.The inventive method principle eliminates the impact of load current on Perfomance of protective relaying; during transmission line heavy service, the inventive method performance is reliable and stable; misoperation can not be there is; effectively can prevent the generation of power grid cascading trip accident when electric network swim is large to be shifted, guarantee power network safety operation.

Accompanying drawing explanation

Fig. 1 is application multi-line power transmission system schematic of the present invention.

Embodiment

Below in conjunction with embodiment, technical scheme of the present invention is expressed in further detail.

Fig. 1 is application multi-line power transmission system schematic of the present invention.In Fig. 1, CVT is voltage transformer, CT is current transformer.The current waveform of protective device to the potential and current transformers CT of the voltage transformer CVT of line protection installation place carries out sampling and obtains voltage, current instantaneous value, and voltage, current instantaneous value that then protective device collects it utilize Fourier algorithm computing electric power line to protect the fault voltage between phases of installation place , fault three-phase current and negative-sequence current between fault phase , as input variable; Wherein, φ φ=AB, BC, CA phase.

Protective device computing electric power line protection seting scope place is to the circuit distance, delta x of phase fault point:

$\mathrm{\&Delta;x}=\left|\frac{{\stackrel{.}{U}}_{\mathrm{\&phi;\&phi;}}-z_1{\stackrel{.}{I}}_{\mathrm{\&phi;\&phi;}}{x}_{\mathrm{set}}}{z_1{\stackrel{.}{I}}_{\mathrm{\&phi;\&phi;}}\sin (\mathrm{\&beta;}+\mathrm{\&gamma;})}\right|\sin \mathrm{\&alpha;}$

Wherein, z ₁for unit length electric transmission line positive sequence impedance; x _setfor line protection setting range; β=Arg (z ₁) be unit length electric transmission line positive sequence impedance z ₁phase angle; for leading angle; for leading angle; φ φ=AB, BC, CA phase.

Protective device judges whether line protection setting range place is greater than zero to the circuit distance, delta x of phase fault point, if line protection setting range place is greater than zero to the circuit distance, delta x of phase fault point, then judge that phase fault point is positioned within line protection setting range, protective device sends action trip signal, the circuit breaker at tripping transmission line two ends; Otherwise if line protection setting range place is less than zero to the circuit distance, delta x of phase fault point, then judge that phase fault point is positioned at outside line protection setting range, protective device sends block signal.

The inventive method principle eliminates the impact of transition resistance on Perfomance of protective relaying, there is the ability of very strong anti-transition resistance impact.The inventive method principle eliminates the impact of load current on Perfomance of protective relaying; during transmission line heavy service, the inventive method performance is reliable and stable; misoperation can not be there is; effectively can prevent the generation of power grid cascading trip accident when electric network swim is large to be shifted, guarantee power network safety operation.

The foregoing is only preferred embodiment of the present invention; but protection scope of the present invention is not limited thereto; anyly be familiar with those skilled in the art in the technical scope that the present invention discloses, the change that can expect easily or replacement, all should be encompassed within protection scope of the present invention.

Claims (1)

1. the line inter-phase fault distance protection method of overload faulty action preventing and resistance to high resistant, is characterized in that, comprises following sequential steps:

(1) the fault voltage between phases of protector measuring line protection installation place , fault three-phase current and negative-sequence current between fault phase , as input variable; Wherein, φ φ=AB, BC, CA phase;

(2) protective device computing electric power line protection seting scope place is to the circuit distance, delta x of phase fault point:

$\mathrm{\&Delta;x}=\left|\frac{{\stackrel{.}{U}}_{\mathrm{\&phi;\&phi;}}-z_1{\stackrel{.}{I}}_{\mathrm{\&phi;\&phi;}}{x}_{\mathrm{set}}}{z_1{\stackrel{.}{I}}_{\mathrm{\&phi;\&phi;}}\sin (\mathrm{\&beta;}+\mathrm{\&gamma;})}\right|\sin \mathrm{\&alpha;}$

Wherein, z ₁for unit length electric transmission line positive sequence impedance; x _setfor line protection setting range; β=Arg (z ₁) be unit length electric transmission line positive sequence impedance z ₁phase angle; for leading angle; for leading angle; φ φ=AB, BC, CA phase;

(3) protective device judges whether line protection setting range place is greater than zero to the circuit distance, delta x of phase fault point, if line protection setting range place is greater than zero to the circuit distance, delta x of phase fault point, then judge that phase fault point is positioned within line protection setting range, protective device sends action trip signal, the circuit breaker at tripping transmission line two ends; Otherwise if line protection setting range place is less than zero to the circuit distance, delta x of phase fault point, then judge that phase fault point is positioned at outside line protection setting range, protective device sends block signal.