CN101359007A - Measurement method for positive sequence parameter of high-voltage transmission line - Google Patents

Abstract

The present invention relates to a positive sequence parameter measurement method of the ultrahigh-tension power transmission line. The measurement method adopts the single-phase testing power supply to exert the positive phase voltage and the reversed phase voltage on the line to be detected, utilizes the measured values of the voltage, the current and the power before and after the reversed phase, combines the measured interference voltage before the voltage is exerted on the line, eliminates the influence of the interference voltage through calculation, and then acquires the phase to phase impedance; and the phase to phase impedances of the other two phases are respectively measured, and the positive sequence parameters of the high voltage transmission line are acquired through calculation. The invention has the advantages that in the environment of strong electromagnetic interference, in particular under the condition that the three phases have different interference voltages, the positive sequence parameters of the high voltage transmission line can be accurately measured; and because of the application of the single phase testing power supply, the size and the weight of the testing device are greatly reduced, the operation is simple and practical, and the invention solves the problem of measuring the positive sequence parameters of the high voltage transmission line on the construction site with strong electromagnetic interference.

Description

Measurement method for positive sequence parameter of high-voltage transmission line

Technical field

The present invention relates to a kind of measurement method for positive sequence parameter of high-voltage transmission line.

Background technology

The measurement method for positive sequence parameter of high-voltage transmission line that uses both at home and abroad is the three-phase supply pressurization at present, the terminal short circuit of transmission line of electricity during measurement, add three phase worker power at circuit top, measure the electric current of each phase, the line voltage and the three-phase general power of three-phase respectively, the voltage, the electric current that record are got arithmetic mean, power is got the algebraic sum of two power meter readings, calculates according to formula to get final product.

Above-mentioned common method is not having under the situation of interference voltage measured result more correct, but owing to developing rapidly of electrical network, the network that ultra-high-tension power transmission line forms is also more and more intensive, because circuit three-phase induction voltage swing is also inequality, when tested ultra-high-tension power transmission line induced voltage is higher, reduce the influence of induced voltage, can only improve trial voltage test result.But can only realize that the increase of three-phase regulator capacity and the appearance of step-up transformer certainly will cause the increase greatly of testing equipment weight and volume by improving ways such as surge capacity and increase step-up transformer like this, more be unfavorable for on-the-spot the use.Therefore under strong electromagnetic, especially run under the very big situation of three-phase induction voltage phase difference, traditional three-phase regulator is difficult to measure the positive order parameter of circuit accurately as experiment power supply.

Summary of the invention

Technical matters to be solved by this invention is the shortcoming at above-mentioned prior art, particularly under the strong electromagnetic condition, under the situation that the three-phase interference voltage has nothing in common with each other again, and provides a kind of method that can accurately measure the positive order parameter of ultra-high-tension power transmission line.

The present invention adopts following technical scheme:

The present invention uses single-phase experiment power supply to treat the survey line road and applies positive phase voltage, reverse voltage, the voltage, electric current, the magnitude of power that utilize anti-phase fore-and-aft survey to obtain, combined circuit applies the interference voltage that records before the voltage, excludes the influence of interference voltage as calculated, obtains alternate impedance; Again other two-phase is measured its alternate impedance respectively, obtain the positive order parameter of ultra-high-tension power transmission line after as calculated; Its concrete grammar step is as follows:

One, measures the alternate impedance Z of ultra-high-tension power transmission line AB _AB:

(1) measurement applies the preceding interference voltage U of voltage _G1:

A, the terminal three-phase shortcircuit of ultra-high-tension power transmission line to be measured is earth-free;

B, use transistor voltmeter are measured the alternate interference voltage U of ultra-high-tension power transmission line AB _G1

(2) add the single-phase experiment power supply E of positive in that described AB is alternate, and apply electric current I ₁, measure the alternate voltage U of AB of this moment ₁, power P ₁, the terminal three-phase shortcircuit of described ultra-high-tension power transmission line is earth-free during measurement;

(3) add anti-phase single-phase testing power supply E in that described AB is alternate, it is alternate to be about to be added in described AB after 180 ° of the described single-phase experiment power supply E phase reversals, and applies electric current I ₂=I ₁, measure the alternate voltage U of AB of this moment ₂, power P ₂, the terminal three-phase shortcircuit of described ultra-high-tension power transmission line is earth-free during measurement;

(4) according to the alternate voltage U of described AB behind following formula (1) the calculating eliminating interference voltage _AB:

Wherein:

U _AB---be the AB voltage between phases behind the eliminating interference voltage;

U ₁---for adding the AB voltage between phases that the positive experiment power supply records;

U ₂---for adding the AB voltage between phases that anti-phase experiment power supply records;

U _G1---be the AB interphase interference voltage that records before pressurizeing;

(5) calculate the alternate impedance Z of getting rid of behind the interference voltage of AB according to following formula (2) _AB

$Z_{\mathrm{AB}}=\frac{U_{\mathrm{AB}}}{I_{\mathrm{AB}}}---\left(2\right)$

Wherein:

Z _AB---be the alternate impedance of AB to be asked;

U _AB---be the AB voltage between phases behind the eliminating interference voltage;

I _AB---for being applied to the alternate test current of AB, its size is I _AB=I ₁=I ₂

Two, measure the alternate impedance Z of high-voltage output line road BC _BC:

Measuring method is with above-mentioned step 1, is that the single-phase experiment power supply E BC that is applied to described ultra-high-tension power transmission line is alternate;

Three, measure the alternate impedance Z of ultra-high-tension power transmission line CA _CA:

Measuring method is with above-mentioned step 1, is that the single-phase experiment power supply E CA that is applied to described ultra-high-tension power transmission line is alternate;

Four, calculate the positive sequence impedance Z of described ultra-high-tension power transmission line according to following formula (3) ₁

$Z_1=\frac{Z_{\mathrm{AB}}+Z_{\mathrm{BC}}+Z_{\mathrm{CA}}}{6}---\left(3\right)$

Wherein:

Z ₁---be the positive sequence impedance of described ultra-high-tension power transmission line to be measured.

Calculating the positive sequence impedance Z of high-tension line ₁After, can further calculate other positive order parameter of high-tension line again according to algorithms most in use, i.e. forward-sequence reactance X ₁=Z ₁Sin φ ₁, positive sequence resistance R ₁=Z ₁Cos φ ₁, φ ₁Positive sequence impedance angle for high-tension line.

In the present invention, the derivation of described formula (1) is as follows:

Applying electric current respectively

After, the voltage that produces at the alternate positive sequence impedance of AB two ends is

Promptly ${\stackrel{\&CenterDot;}{U}}_{\mathrm{AB}1}={\stackrel{\&CenterDot;}{I}}_1{Z}_{\mathrm{AB}},$ ${\stackrel{\&CenterDot;}{U}}_{\mathrm{<figure-callout\; id="2"\; label="AB"\; filenames="A20081007945500083.png"\; state="\{\{state\}\}">AB</figure-callout>}2}={\stackrel{\&CenterDot;}{I}}_2{Z}_{\mathrm{AB}}$ (see figure 2) is owing to have interference voltage on the circuit

Existence,

Can not directly measure in test, they are amounts to be asked.

Apply the equal-sized electric current of amplitude before and after the paraphase of warranty test power supply, promptly $\left|{\stackrel{\&CenterDot;}{I}}_1\right|=\left|{\stackrel{\&CenterDot;}{I}}_2\right|$ (see figure 2) then has $\left|{\stackrel{\&CenterDot;}{U}}_{\mathrm{AB}1}\right|=\left|{\stackrel{\&CenterDot;}{U}}_{\mathrm{AB}2}\right|,$ According to getting by the loop voltage equation before and after the paraphase among Fig. 2: $|{\stackrel{\&CenterDot;}{U}}_1+{\stackrel{\&CenterDot;}{U}}_g|=|{\stackrel{\&CenterDot;}{U}}_2+{\stackrel{\&CenterDot;}{U}}_g|,$ Then polar plot as shown in Figure 3.

Then in Fig. 3, in two of the first half triangles 1,2, can get by the cosine law:

$\cos \mathrm{\&alpha;}=\frac{{\mathrm{<figure-callout\; id="2"\; label="U"\; filenames="A20081007945500083.png"\; state="\{\{state\}\}">U</figure-callout>}}_2^2+U_g^2-{\mathrm{<figure-callout\; id="2"\; label="U\; AB"\; filenames="A20081007945500083.png"\; state="\{\{state\}\}">U</figure-callout>}}_{\mathrm{AB}}^2}{2U_2{U}_g}---\left(4\right)$

$\cos \mathrm{\&beta;}=\frac{U_1^2+U_g^2-U_{\mathrm{AB}1}^2}{2U_1{U}_g}---\left(5\right)$

Because of 180 ° of single phase poaer supply phase change before and after the paraphase, cos α+cos β=0 is arranged then again, can get above-mentioned formula (1):

$U_{\mathrm{AB}}=U_{\mathrm{AB}1}={\mathrm{<figure-callout\; id="2"\; label="U\; AB"\; filenames="A20081007945500083.png"\; state="\{\{state\}\}">U</figure-callout>}}_{\mathrm{AB}}=\sqrt{U_1\&CenterDot;{\mathrm{<figure-callout\; id="2"\; label="U"\; filenames="A20081007945500083.png"\; state="\{\{state\}\}">U</figure-callout>}}_2+{\mathrm{<figure-callout\; id="2"\; label="U\; g"\; filenames="A20081007945500083.png"\; state="\{\{state\}\}">U</figure-callout>}}_g^{}}$

Again above-mentioned formula (3) is described as follows below:

As shown in Figure 1, Z _AB=Z _AO+ Z _BO

Z _BC＝Z _BO+Z _CO

Z _CA＝Z _CO+Z _AO

Wherein: Z _AB---the alternate positive sequence impedance of AB

Z _BC---the alternate positive sequence impedance of BC

Z _CA---the alternate positive sequence impedance of CA

Thereby the positive sequence impedance of three-phase line

$Z_1=\frac{Z_{\mathrm{AO}}+Z_{\mathrm{BO}}+Z_{\mathrm{CO}}}{3}=\frac{2Z_{\mathrm{AO}}+2Z_{\mathrm{BO}}+2Z_{\mathrm{CO}}}{6}$

$=\frac{(Z_{\mathrm{AO}}+Z_{\mathrm{BO}})+(Z_{\mathrm{BO}}+Z_{\mathrm{CO}})+(Z_{\mathrm{CO}}+Z_{\mathrm{AO}})}{6}$

$=\frac{Z_{\mathrm{AB}}+Z_{\mathrm{BC}}+Z_{\mathrm{CA}}}{6}$

Good effect of the present invention is can be under strong electromagnetic interference environment, particularly under the situation that the three-phase interference voltage has nothing in common with each other, accurately measure the positive order parameter of ultra-high-tension power transmission line, and owing to use single-phase experiment power supply, the test unit volume and weight is all alleviated greatly, convenient and practical, solved engineering site is measured the positive order parameter of ultra-high-tension power transmission line under strong electromagnetic a difficult problem.

Description of drawings

Fig. 1 is a single-phase experiment power supply test wiring diagram of the present invention.

Fig. 2 is the equivalent electrical circuit of Fig. 1, and wherein (a) is the equivalent electrical circuit before the paraphase, (b) is the equivalent electrical circuit after the paraphase.

Fig. 3 is the vector correlation figure of measuring voltage and interference voltage.

In the accompanying drawings: E-single-phase experiment power supply, W-power meter, V-voltage table, A-reometer.

Embodiment

Get final product according to the technical scheme concrete operations described in the foregoing invention content.Apply electric current I ₁Definite principle: because experiment power supply capacity and line length is different, the test current that generally applies

Amplitude (promptly $\left|{\stackrel{\&CenterDot;}{I}}_1\right|=\left|{\stackrel{\&CenterDot;}{I}}_2\right|$ ) about 10～15A.

Claims (1)

1, measurement method for positive sequence parameter of high-voltage transmission line, it is characterized in that using single-phase experiment power supply to treat the survey line road and apply positive phase voltage, reverse voltage, the voltage, electric current, the magnitude of power that utilize anti-phase fore-and-aft survey to obtain, combined circuit applies the interference voltage that records before the voltage, exclude the influence of interference voltage as calculated, obtain alternate impedance; Again other two-phase is measured its alternate impedance respectively, obtain the positive order parameter of ultra-high-tension power transmission line after as calculated; Its concrete grammar step is as follows:

One, measures the alternate impedance Z of ultra-high-tension power transmission line AB _AB:

(1) measurement applies the preceding interference voltage U of voltage _G1:

A, the terminal three-phase shortcircuit of ultra-high-tension power transmission line to be measured is earth-free;

B, use transistor voltmeter are measured the alternate interference voltage U of ultra-high-tension power transmission line AB _G1

(2) add the single-phase experiment power supply E of positive in that described AB is alternate, and apply electric current I ₁, measure the alternate voltage U of AB of this moment ₁, power P ₁, the terminal three-phase shortcircuit of described ultra-high-tension power transmission line is earth-free during measurement;

(3) add anti-phase single-phase testing power supply E in that described AB is alternate, it is alternate to be about to be added in described AB after 180 ° of the described single-phase experiment power supply E phase reversals, and applies electric current I ₂=I ₁, measure the alternate voltage U of AB of this moment ₂, power P ₂, the terminal three-phase shortcircuit of described ultra-high-tension power transmission line is earth-free during measurement;

(4) according to the alternate voltage U of described AB behind following formula (1) the calculating eliminating interference voltage _AB:

$U_{\mathrm{AB}}=\sqrt{U_1\&CenterDot;U_2+U_{g1}^2}---\left(1\right)$

Wherein:

U _AB---be the AB voltage between phases behind the eliminating interference voltage;

U ₁---for adding the AB voltage between phases that the positive experiment power supply records;

U ₂---for adding the AB voltage between phases that anti-phase experiment power supply records;

U _G1---be the AB interphase interference voltage that records before pressurizeing;

(5) calculate the alternate impedance Z of getting rid of behind the interference voltage of AB according to following formula (2) _AB

$Z_{\mathrm{AB}}=\frac{U_{\mathrm{AB}}}{I_{\mathrm{AB}}}---\left(2\right)$

Wherein:

Z _AB---be the alternate impedance of AB to be asked;

U _AB---be the AB voltage between phases behind the eliminating interference voltage;

I _AB---for being applied to the alternate test current of AB, its size is I _AB=I ₁=I ₂

Two, measure the alternate impedance Z of high-voltage output line road BC _BC:

Measuring method is with above-mentioned step 1, is that the single-phase experiment power supply E BC that is applied to described ultra-high-tension power transmission line is alternate;

Three, measure the alternate impedance Z of ultra-high-tension power transmission line CA _CA:

Measuring method is with above-mentioned step 1, is that the single-phase experiment power supply E CA that is applied to described ultra-high-tension power transmission line is alternate;

Four, calculate the positive sequence impedance Z of described ultra-high-tension power transmission line according to following formula (3) ₁

$Z_1=\frac{Z_{\mathrm{AB}}+Z_{\mathrm{BC}}+Z_{\mathrm{CA}}}{6}---\left(3\right)$

Wherein:

Z ₁---be the positive sequence impedance of described ultra-high-tension power transmission line to be measured.

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