CN103163423A - Method using dynamic extraction coefficient to achieve line single-phase ground connection fault single end distance measurement - Google Patents

Abstract

Line single-phase earth fault single-terminal location method is realized using Dynamic Extraction coefficient the invention discloses a kind of. This method calculates Dynamic Extraction coefficient first with the failure phase electrical quantity that protection arrives

, then extracted by faulted phase voltage using Dynamic Extraction coefficient divided by the true fault distance x in faulted phase current and the ratio of unit length route positive sequence impedance product, calculating formula is . The influence of earth fault voltage is considered in the design of the method for the present invention algorithm, so that fault localization precision is not influenced by factors such as transition resistance, load current and abort situation, there is good fault localization precision.

Description

A kind of Dynamic Extraction coefficient that utilizes is realized the line single phase grounding failure method of single end distance measurement

Technical field

The present invention relates to electric power system fault ranging technology field, specifically relate to a kind of Dynamic Extraction coefficient that utilizes and realize the line single phase grounding failure method of single end distance measurement.

Background technology

The calculating formula that fault distance is measured in the distance protection of tradition impedance ground is

Due to

, so calculating formula

, namely measure fault distance

Result of calculation formed by two parts: a part is the line protection installation place fault distance x to Single-phase Ground Connection Failure, and another part is the additional fault distance

Above-mentioned various in, Be fault phase voltage,

Be the earth fault point voltage, Be the fault phase electric current, Be zero-sequence current, φ=A, B, C phase, z ₁, z ₀Be respectively unit length transmission line of electricity positive sequence impedance, zero sequence impedance, x is that the line protection installation place is to the fault distance of Single-phase Ground Connection Failure, x _ceThe fault distance that obtains for traditional impedance ground distance protection computation and measurement.The additional fault distance that causes because of the earth fault point voltage

Can cause the fault distance measurement result to have larger error, when transition resistance causes that the earth fault point voltage is larger, even can cause the one-end fault ranging failure especially, can't provide position of failure point information for the transmission line malfunction line walking, be unfavorable for the fault eliminating.

Summary of the invention

The object of the invention is to overcome the deficiency that prior art exists, have good fault localization precision, a kind of Dynamic Extraction coefficient that utilizes that the fault localization precision is not affected by the factors such as transition resistance, load current and abort situation is realized the line single phase grounding failure method of single end distance measurement.

A kind of Dynamic Extraction coefficient that utilizes is realized the line single phase grounding failure method of single end distance measurement, comprises the following steps:

(1) the protective device data acquisition system (DAS) is measured the fault phase voltage of line protection installation place in real time

, the fault phase electric current

, the fault phase negative-sequence current

And zero-sequence current

Wherein, φ=A phase or B phase or C phase.

(2) the protective device data acquisition system (DAS) sends its data of obtaining to the protective device data handling system, and the protective device data handling system utilizes the data that data acquisition system (DAS) sends to calculate the Dynamic Extraction coefficient

Wherein,

β=Arg (z ₁); z ₁Be unit length transmission line of electricity positive sequence impedance; z ₀Be the impedance of unit length power transmission line zero-sequence.

(3) the fault distance x of Single-phase Ground Connection Failure is arrived in protective device data handling system computing electric power line protection installation place:

$x=k\frac{{\stackrel{\·}{U}}_{\mathrm{\φ}}}{z_1({\stackrel{\·}{I}}_{\mathrm{\φ}}+\frac{z_0-z_1}{z_1}{\stackrel{\·}{I}}_0)}=\frac{\sin \mathrm{\θ}}{\sin (\mathrm{\α}+\mathrm{\β})}\frac{{\stackrel{\·}{U}}_{\mathrm{\φ}}}{z_1({\stackrel{\·}{I}}_{\mathrm{\φ}}+\frac{z_0-z_1}{z_1}{\stackrel{\·}{I}}_0)}$

In sum, the present invention has following advantage compared to existing technology:

At first the inventive method utilizes the fault phase electric parameters that protection arrives to calculate the Dynamic Extraction coefficient; then adopt the Dynamic Extraction coefficient to extract by fault phase voltage divided by the true fault distance in the ratio of fault phase electric current and unit length circuit positive sequence impedance product; has good fault localization precision; the fault localization precision is not subjected to the impact of the factors such as transition resistance, load current and abort situation, has very high distance accuracy.

Description of drawings

Fig. 1 is for using circuit transmission system schematic diagram of the present invention.

Embodiment

Below in conjunction with accompanying drawing, technical scheme of the present invention is done further statement in detail.

In Fig. 1, CVT is that capacitance type potential transformer, CT are current transformer.After transmission line of electricity generation singlephase earth fault, the protective device data acquisition system (DAS) is measured the fault phase voltage of line protection installation place in real time

, the fault phase electric current , the fault phase negative-sequence current And zero-sequence current

Wherein, φ=A phase or B phase or C phase.

The protective device data acquisition system (DAS) sends its data of obtaining to the protective device data handling system, and the protective device data handling system utilizes the data that data acquisition system (DAS) sends to calculate the Dynamic Extraction coefficient

Wherein,

β=Arg (z1); z ₁Be unit length transmission line of electricity positive sequence impedance; z ₀Be the impedance of unit length power transmission line zero-sequence.

The fault distance x of Single-phase Ground Connection Failure is arrived in protective device data handling system computing electric power line protection installation place:

$x=k\frac{{\stackrel{\·}{U}}_{\mathrm{\φ}}}{z_1({\stackrel{\·}{I}}_{\mathrm{\φ}}+\frac{z_0-z_1}{z_1}{\stackrel{\·}{I}}_0)}=\frac{\sin \mathrm{\θ}}{\sin (\mathrm{\α}+\mathrm{\β})}\frac{{\stackrel{\·}{U}}_{\mathrm{\φ}}}{z_1({\stackrel{\·}{I}}_{\mathrm{\φ}}+\frac{z_0-z_1}{z_1}{\stackrel{\·}{I}}_0)}$

At first the inventive method utilizes the fault phase electric parameters that protection arrives to calculate the Dynamic Extraction coefficient; then adopt the Dynamic Extraction coefficient to extract by fault phase voltage divided by the true fault distance in the ratio of fault phase electric current and unit length circuit positive sequence impedance product; have good fault localization precision, the fault localization precision is not subjected to the impact of the factors such as transition resistance, load current and abort situation.

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

Claims (1)

1. one kind is utilized the Dynamic Extraction coefficient to realize the line single phase grounding failure method of single end distance measurement, it is characterized in that: comprise the steps,

(1) the protective device data acquisition system (DAS) is measured the fault phase voltage of line protection installation place in real time

, the fault phase electric current

, the fault phase negative-sequence current And zero-sequence current

Wherein, φ=A phase or B phase or C phase,

(2) the protective device data acquisition system (DAS) sends its data of obtaining to the protective device data handling system, and the protective device data handling system utilizes the data that data acquisition system (DAS) sends to calculate the Dynamic Extraction coefficient

, wherein,

β=Arg (z ₁); z ₁Be unit length transmission line of electricity positive sequence impedance; z ₀Be the impedance of unit length power transmission line zero-sequence,

(3) the fault distance x of Single-phase Ground Connection Failure is arrived in protective device data handling system computing electric power line protection installation place:

$x=k\frac{{\stackrel{\·}{U}}_{\mathrm{\φ}}}{z_1({\stackrel{\·}{I}}_{\mathrm{\φ}}+\frac{z_0-z_1}{z_1}{\stackrel{\·}{I}}_0)}=\frac{\sin \mathrm{\θ}}{\sin (\mathrm{\α}+\mathrm{\β})}\frac{{\stackrel{\·}{U}}_{\mathrm{\φ}}}{z_1({\stackrel{\·}{I}}_{\mathrm{\φ}}+\frac{z_0-z_1}{z_1}{\stackrel{\·}{I}}_0)}$ ?。

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