CN104037742A - Extra-high voltage alternating current transmission line protection method - Google Patents

Abstract

The invention discloses an extra-high voltage alternating current transmission line protection method. The method includes the steps of firstly, adopting distribution parameters for modeling, calculating the A, B and C phase positive-sequence current at one end of an extra-high voltage alternating current transmission line through the A, B and C phase positive-sequence voltage and the A, B and C phase positive-sequence current at the other end of the extra-high voltage alternating current transmission line, respectively calculating A, B and C phase positive-sequence difference current amplitudes, further calculating a full-component positive-sequence difference coefficient matrix, and judging a fault phase line according to the relationship between elements of the full-component positive-sequence difference coefficient matrix. By means of the extra-high voltage alternating current transmission line protection method, the motion performance is not influenced by the distributed capacitance current, the transition resistance and the load current, the relay protection function that a single phase fault line is tripped off when a single phase line fault occurs is achieved, and the method is suitable for any voltage class, is particularly suitable for replay protection of the extra-high voltage alternating current transmission line, and is also suitable for replay protection of the whole fault process after the extra-high voltage alternating current transmission line is failed.

Description

Ultrahigh voltage alternating current transmission lines guard method

Technical field

The present invention relates to Relay Protection Technology in Power System field, specifically relate to a kind of ultrahigh voltage alternating current transmission lines guard method based on full component positive sequence differential factor matrix.

Background technology

Ultra-high voltage AC transmission network can significantly improve electrical network transmission capacity, is conducive to reduce transmission losses, saves Transmission Cost, energy-saving and emission-reduction, thus promote green energy resource expanding economy, can make again electrical network more intelligent, strong, stable, reliable.Meanwhile, as the key rack of electrical network, after ultrahigh voltage alternating current transmission lines breaks down, if fault can not detect in time and correctly isolation, can cause stability of power system to be damaged, even may cause mains breakdown, thereby social economy is produced and causes loss difficult to the appraisal.

Owing to not affected by power system operation mode and electric network composition, and have natural phase-selecting function, current differential protection is the main protection of various electric pressure transmission lines always.In 500kV and following electric pressure transmission line, because transmission line capacitance current along the line is very little, distributed capacitance is very little on the impact of current differential protection performance.But; the voltage of ultrahigh voltage alternating current transmission lines, current delivery have obvious wave process; capacitance current along the line is very large; utilize two ends current phasor and amplitude to be faced with current differential protection starting current as the conventional current differential protection of actuating quantity large; and in order to prevent current differential protection malfunction; improve startup set point and can cause again differential protection sensitivity deficiency, restricting the application of conventional current differential protection on ultrahigh voltage alternating current transmission lines.

Owing to affected by load current; when the single-phase high resistance earthing fault of transmission line; directly utilize two ends current phasor and amplitude as the correctly tripping fault phase of conventional current differential protection of actuating quantity, but by Zero sequence current differential protection as its backup protection action tripping three-phase line.Due to non-full-operating state on the impact of the stabilization of power grids situation much smaller than three-phase tripping, can strengthen the impact of fault to grid stability by Zero sequence current differential protection action tripping three-phase line This move strategy.Therefore, when single-phase high resistance ground short trouble occurs transmission line, if the correct tripping fault phase of energy retains all the other two normal phases and continues operation, be conducive to strengthen grid stability, can make electrical network stronger reliable.

Summary of the invention

The object of the invention is to overcome the deficiency that prior art exists, a kind of ultrahigh voltage alternating current transmission lines guard method based on full component positive sequence differential factor matrix is provided.The inventive method physical model adopts distributed parameter model, and performance is not subject to the impact of capacitance current, is applicable to the relaying protection of any electric pressure, particularly ultrahigh voltage alternating current transmission lines.The inventive method is applicable to the relaying protection of whole failure process after ultrahigh voltage alternating current transmission lines fault; performance is not subject to the impact of transition resistance and load current; especially in the time there is single-phase high resistance earthing fault in ultrahigh voltage alternating current transmission lines; the inventive method is reliable recognition fault phase correctly, realizes the relay protection function of uniline fault tripping single-phase fault circuit.

The technical scheme adopting that the present invention solves its technical problem is:

Ultrahigh voltage alternating current transmission lines guard method, it comprises the following steps:

(1) measure A, B, the C phase positive sequence voltage of ultrahigh voltage alternating current transmission lines in m transforming plant protecting installation place a, B, C phase forward-order current measure A, B, the C phase forward-order current of ultrahigh voltage alternating current transmission lines in n transforming plant protecting installation place

(2) utilize A, B, the C phase positive sequence voltage of ultrahigh voltage alternating current transmission lines in m transforming plant protecting installation place a, B, C phase forward-order current calculate A, B, the C phase forward-order current of ultrahigh voltage alternating current transmission lines in n transforming plant protecting installation place

${\stackrel{\·}{I}}_{\mathrm{mnA}1}={\stackrel{\·}{I}}_{\mathrm{mA}1}\cosh \left({\mathrm{\γ}}_1{l}_{\mathrm{mn}}\right)-\frac{{\stackrel{\·}{U}}_{\mathrm{mA}1}}{Z_{c1}}\sinh \left({\mathrm{\γ}}_1{l}_{\mathrm{mn}}\right)$

${\stackrel{\·}{I}}_{\mathrm{mnB}1}={\stackrel{\·}{I}}_{\mathrm{mB}1}\cosh \left({\mathrm{\γ}}_1{l}_{\mathrm{mn}}\right)-\frac{{\stackrel{\·}{U}}_{\mathrm{mB}1}}{Z_{c1}}\sinh \left({\mathrm{\γ}}_1{l}_{\mathrm{mn}}\right)$

${\stackrel{\·}{I}}_{\mathrm{mnC}1}={\stackrel{\·}{I}}_{\mathrm{mC}1}\cosh \left({\mathrm{\γ}}_1{l}_{\mathrm{mn}}\right)-\frac{{\stackrel{\·}{U}}_{\mathrm{mC}1}}{Z_{c1}}\sinh \left({\mathrm{\γ}}_1{l}_{\mathrm{mn}}\right)$

Wherein, γ ₁for ultrahigh voltage alternating current transmission lines positive sequence propagation constant; Z _c1for ultrahigh voltage alternating current transmission lines positive sequence wave impedance; l _mnfor the ultrahigh voltage alternating current transmission lines length between m transformer station and n transformer station; Cosh (.) is hyperbolic cosine function; Sinh (.) is hyperbolic sine function;

(3) calculate $I_{\mathrm{dA}1}=|{\stackrel{\·}{I}}_{\mathrm{mnA}1}+{\stackrel{\·}{I}}_{\mathrm{nA}1}|,I_{\mathrm{dB}1}=|{\stackrel{\·}{I}}_{\mathrm{mnB}1}+{\stackrel{\·}{I}}_{\mathrm{nB}1}|,I_{\mathrm{dC}1}=|{\stackrel{\·}{I}}_{\mathrm{mnC}1}+{\stackrel{\·}{I}}_{\mathrm{nC}1}|,$ Calculate full component positive sequence differential factor matrix

$S=\left[\begin{array}{ccc}1& \frac{I_{\mathrm{dA}1}}{I_{\mathrm{dB}1}}& \frac{I_{\mathrm{dA}1}}{I_{\mathrm{dC}1}}\\ \frac{I_{\mathrm{dB}1}}{I_{\mathrm{dA}1}}& 1& \frac{I_{\mathrm{dB}1}}{I_{\mathrm{dC}1}}\\ \frac{I_{\mathrm{dC}1}}{I_{\mathrm{dA}1}}& \frac{I_{\mathrm{dC}1}}{I_{\mathrm{dB}1}}& 1\end{array}\right];$

(4) choose the greatest member in full component positive sequence differential factor matrix S basis choose the element in full component positive sequence differential factor matrix S with set threshold values α, utilize following relaying protection criterion failure judgement phase circuit:

(i) if meet S _ij> α and S _ik> α, judges that i phase circuit is fault phase circuit;

(ii) if meet S _ij> α and S _kj> α, judges that ik phase circuit is fault phase circuit;

(iii) if meet α >S _ij>1, judges that ABC phase circuit is fault phase circuit; Wherein, ijk=ABC, ACB, BAC, BCA, CAB, CBA phase.

The technical program is compared with background technology, and its tool has the following advantages:

The inventive method physical model adopts distributed parameter model, and performance is not subject to the impact of capacitance current, is applicable to the relaying protection of any electric pressure, particularly ultrahigh voltage alternating current transmission lines.The inventive method is applicable to the relaying protection of whole failure process after ultrahigh voltage alternating current transmission lines fault; performance is not subject to the impact of transition resistance and load current; especially in the time there is single-phase high resistance earthing fault in ultrahigh voltage alternating current transmission lines; the inventive method is reliable recognition fault phase correctly, realizes the relay protection function of uniline fault tripping single-phase fault circuit.

Brief description of the drawings

Below in conjunction with drawings and Examples, the invention will be further described.

Fig. 1 is the ultrahigh voltage alternating current transmission lines fault schematic diagram of application the inventive method.

Embodiment

Fig. 1 is the ultrahigh voltage alternating current transmission lines fault schematic diagram of application the inventive method.Ultrahigh voltage alternating current transmission lines is measured by the synchronous phasor measurement unit (phase measurement unit, PMU) that is arranged on this two transformer station respectively in the fundamental frequency electric parameters of m side transformer station and n side transforming plant protecting installation place.Synchronous phasor measurement unit is measured A, B, the C phase positive sequence voltage of ultrahigh voltage alternating current transmission lines in m transforming plant protecting installation place a, B, C phase forward-order current measure A, B, the C phase forward-order current of ultrahigh voltage alternating current transmission lines in n transforming plant protecting installation place the measurement data of synchronous phasor measurement unit sends ultrahigh voltage alternating current transmission lines protective relaying device to through fibre optic data transmission passage, and ultrahigh voltage alternating current transmission lines protective relaying device completes ultrahigh voltage alternating current transmission lines relay protection function by application the inventive method:

Utilize A, B, the C phase positive sequence voltage of ultrahigh voltage alternating current transmission lines in m transforming plant protecting installation place a, B, C phase forward-order current calculate A, B, the C phase forward-order current of ultrahigh voltage alternating current transmission lines in n transforming plant protecting installation place

${\stackrel{\·}{I}}_{\mathrm{mnA}1}={\stackrel{\·}{I}}_{\mathrm{mA}1}\cosh \left({\mathrm{\γ}}_1{l}_{\mathrm{mn}}\right)-\frac{{\stackrel{\·}{U}}_{\mathrm{mA}1}}{Z_{c1}}\sinh \left({\mathrm{\γ}}_1{l}_{\mathrm{mn}}\right)$

${\stackrel{\·}{I}}_{\mathrm{mnB}1}={\stackrel{\·}{I}}_{\mathrm{mB}1}\cosh \left({\mathrm{\γ}}_1{l}_{\mathrm{mn}}\right)-\frac{{\stackrel{\·}{U}}_{\mathrm{mB}1}}{Z_{c1}}\sinh \left({\mathrm{\γ}}_1{l}_{\mathrm{mn}}\right)$

${\stackrel{\·}{I}}_{\mathrm{mnC}1}={\stackrel{\·}{I}}_{\mathrm{mC}1}\cosh \left({\mathrm{\γ}}_1{l}_{\mathrm{mn}}\right)-\frac{{\stackrel{\·}{U}}_{\mathrm{mC}1}}{Z_{c1}}\sinh \left({\mathrm{\γ}}_1{l}_{\mathrm{mn}}\right)$

Wherein, γ ₁for ultrahigh voltage alternating current transmission lines positive sequence propagation constant; Z _c1for ultrahigh voltage alternating current transmission lines positive sequence wave impedance; l _mnfor the ultrahigh voltage alternating current transmission lines length between m transformer station and n transformer station; Cosh (.) is hyperbolic cosine function; Sinh (.) is hyperbolic sine function.

Calculate $I_{\mathrm{dA}1}=|{\stackrel{\·}{I}}_{\mathrm{mnA}1}+{\stackrel{\·}{I}}_{\mathrm{nA}1}|,I_{\mathrm{dB}1}=|{\stackrel{\·}{I}}_{\mathrm{mnB}1}+{\stackrel{\·}{I}}_{\mathrm{nB}1}|,I_{\mathrm{dC}1}=|{\stackrel{\·}{I}}_{\mathrm{mnC}1}+{\stackrel{\·}{I}}_{\mathrm{nC}1}|.$

Calculate full component positive sequence differential factor matrix $S=\left[\begin{array}{ccc}1& \frac{I_{\mathrm{dA}1}}{I_{\mathrm{dB}1}}& \frac{I_{\mathrm{dA}1}}{I_{\mathrm{dC}1}}\\ \frac{I_{\mathrm{dB}1}}{I_{\mathrm{dA}1}}& 1& \frac{I_{\mathrm{dB}1}}{I_{\mathrm{dC}1}}\\ \frac{I_{\mathrm{dC}1}}{I_{\mathrm{dA}1}}& \frac{I_{\mathrm{dC}1}}{I_{\mathrm{dB}1}}& 1\end{array}\right].$

Choose the greatest member in full component positive sequence differential factor matrix S basis choose the element in full component positive sequence differential factor matrix S with set threshold values α, utilize following relaying protection criterion failure judgement phase circuit:

(i) if meet S _ij> α and S _ik> α, judges that i phase circuit is fault phase circuit;

(ii) if meet S _ij> α and S _kj> α, judges that ik phase circuit is fault phase circuit;

(iii) if meet α >S _ij>1, judges that ABC phase circuit is fault phase circuit; Wherein, ijk=ABC, ACB, BAC, BCA, CAB, CBA phase.

The inventive method physical model adopts distributed parameter model, and performance is not subject to the impact of capacitance current, is applicable to the relaying protection of any electric pressure, particularly ultrahigh voltage alternating current transmission lines.The inventive method is applicable to the relaying protection of whole failure process after ultrahigh voltage alternating current transmission lines fault; performance is not subject to the impact of transition resistance and load current; especially in the time there is single-phase high resistance earthing fault in ultrahigh voltage alternating current transmission lines; the inventive method is reliable recognition fault phase correctly, realizes the relay protection function of uniline fault tripping single-phase fault circuit.

The above, only for preferred embodiment of the present invention, therefore can not limit according to this scope of the invention process, the equivalence of doing according to the scope of the claims of the present invention and description changes and modifies, and all should still belong in the scope that the present invention contains.

Claims (1)

1. ultrahigh voltage alternating current transmission lines guard method, is characterized in that: comprise the following steps:

(1) measure A, B, the C phase positive sequence voltage of ultrahigh voltage alternating current transmission lines in m transforming plant protecting installation place a, B, C phase forward-order current measure A, B, the C phase forward-order current of ultrahigh voltage alternating current transmission lines in n transforming plant protecting installation place

(2) utilize A, B, the C phase positive sequence voltage of ultrahigh voltage alternating current transmission lines in m transforming plant protecting installation place a, B, C phase forward-order current calculate A, B, the C phase forward-order current of ultrahigh voltage alternating current transmission lines in n transforming plant protecting installation place

${\stackrel{\·}{I}}_{\mathrm{mnA}1}={\stackrel{\·}{I}}_{\mathrm{mA}1}\cosh \left({\mathrm{\γ}}_1{l}_{\mathrm{mn}}\right)-\frac{{\stackrel{\·}{U}}_{\mathrm{mA}1}}{Z_{c1}}\sinh \left({\mathrm{\γ}}_1{l}_{\mathrm{mn}}\right)$

${\stackrel{\·}{I}}_{\mathrm{mnB}1}={\stackrel{\·}{I}}_{\mathrm{mB}1}\cosh \left({\mathrm{\γ}}_1{l}_{\mathrm{mn}}\right)-\frac{{\stackrel{\·}{U}}_{\mathrm{mB}1}}{Z_{c1}}\sinh \left({\mathrm{\γ}}_1{l}_{\mathrm{mn}}\right)$

${\stackrel{\·}{I}}_{\mathrm{mnC}1}={\stackrel{\·}{I}}_{\mathrm{mC}1}\cosh \left({\mathrm{\γ}}_1{l}_{\mathrm{mn}}\right)-\frac{{\stackrel{\·}{U}}_{\mathrm{mC}1}}{Z_{c1}}\sinh \left({\mathrm{\γ}}_1{l}_{\mathrm{mn}}\right)$

Wherein, γ ₁for ultrahigh voltage alternating current transmission lines positive sequence propagation constant; Z _c1for ultrahigh voltage alternating current transmission lines positive sequence wave impedance; l _mnfor the ultrahigh voltage alternating current transmission lines length between m transformer station and n transformer station; Cosh (.) is hyperbolic cosine function; Sinh (.) is hyperbolic sine function;

(3) calculate $I_{\mathrm{dA}1}=|{\stackrel{\·}{I}}_{\mathrm{mnA}1}+{\stackrel{\·}{I}}_{\mathrm{nA}1}|,I_{\mathrm{dB}1}=|{\stackrel{\·}{I}}_{\mathrm{mnB}1}+{\stackrel{\·}{I}}_{\mathrm{nB}1}|,I_{\mathrm{dC}1}=|{\stackrel{\·}{I}}_{\mathrm{mnC}1}+{\stackrel{\·}{I}}_{\mathrm{nC}1}|,$ Calculate full component positive sequence differential factor matrix

$S=\left[\begin{array}{ccc}1& \frac{I_{\mathrm{dA}1}}{I_{\mathrm{dB}1}}& \frac{I_{\mathrm{dA}1}}{I_{\mathrm{dC}1}}\\ \frac{I_{\mathrm{dB}1}}{I_{\mathrm{dA}1}}& 1& \frac{I_{\mathrm{dB}1}}{I_{\mathrm{dC}1}}\\ \frac{I_{\mathrm{dC}1}}{I_{\mathrm{dA}1}}& \frac{I_{\mathrm{dC}1}}{I_{\mathrm{dB}1}}& 1\end{array}\right];$

(4) choose the greatest member in full component positive sequence differential factor matrix S basis choose the element in full component positive sequence differential factor matrix S with set threshold values α, utilize following relaying protection criterion failure judgement phase circuit:

(i) if meet S _ij> α and S _ik> α, judges that i phase circuit is fault phase circuit;

(ii) if meet S _ij> α and S _kj> α, judges that ik phase circuit is fault phase circuit;

(iii) if meet α >S _ij>1, judges that ABC phase circuit is fault phase circuit; Wherein, ijk=ABC, ACB, BAC, BCA, CAB, CBA phase.