CN104078950B - Ultra-high voltage transmission line relay protection method based on positive-sequence break variable differential coefficient matrix - Google Patents

Abstract

Provided is an ultra-high voltage transmission line relay protection method based on a positive-sequence break variable differential coefficient matrix. The method comprises the steps of measuring the A-phase positive-sequence voltage break variable, the B-phase positive-sequence voltage break variable, the C-phase positive-sequence voltage break variable, the A-phase positive-sequence current break variable, the B-phase positive-sequence current break variable and the C-phase positive-sequence current break variable of one end of an ultra-high voltage transmission line; calculating the A-phase positive-sequence current break variable, the B-phase positive-sequence current break variable and the C-phase positive-sequence current break variable of the other end of the ultra-high voltage transmission line according to the A-phase positive-sequence voltage break variable, the B-phase positive-sequence voltage break variable, the C-phase positive-sequence voltage break variable, the A-phase positive-sequence current break variable, the B-phase positive-sequence current break variable and the C-phase positive-sequence current break variable of one end of the ultra-high voltage transmission line through a distributed parameter model; calculating the A-phase positive-sequence break variable differential current amplitude, the B-phase positive-sequence break variable differential current amplitude and the C-phase positive-sequence break variable differential current magnitude respectively, and then calculating the positive-sequence break variable differential coefficient matrix; discriminating the fault phase of the ultra-high voltage transmission line according to the magnitude relation between elements of the positive-sequence break variable differential coefficient matrix. The distributed parameter model serves as a physical model in the method, the method is not influenced by distributed capacitive currents and is suitable for any voltage class and particularly suitable for relay protection within two cycles after a fault of the ultra-high voltage transmission line, and the motion performance is not influenced by transition resistance or load currents.

Description

Based on positive sequence Sudden Changing Rate differential factor matrix extra-high voltage transmission line relay protecting method

Technical field

The present invention relates to Relay Protection Technology in Power System field, it is a kind of poor based on positive sequence Sudden Changing Rate to concretely relate to Dynamic coefficient matrix extra-high voltage transmission line relay protecting method.

Background technology

The built first southeast Shanxi-Nanyang being formally incorporated into the power networks-Jingmen 1000kV extra-high voltage in the world of China at present Transmission line of electricity.According to State Grid Corporation of China《Unified strong intelligent grid research report》, before 2015 China will build up extra-high 3.9 ten thousand kilometers of pressure transmission line, will build up 4.7 ten thousand kilometers of UHV transmission line, substantially build up with extra-high piezoelectricity before the year two thousand twenty Net is bulk transmission grid, the national grid general layout of electric network coordination development at different levels.

UHV transmission network can be greatly improved electrical energy transportation capacity, alleviate the nervous capacity situation of China, be conducive to subtracting Few transmission losses, saving Transmission Cost, energy-saving and emission-reduction, thus promoting green energy resource expanding economy, can make China Power Grids more again Plus it is intelligent, strong, stable, reliable.Meanwhile, as electrical network bulk transmission grid, after UHV transmission line breaks down, if fault is not Can be able in time detection to and correctly excise, stability of power system can be led to be destroyed in some instances it may even be possible to cause system crash, Thus social economy can be produced loss difficult to the appraisal is caused.

Due to not affected, and being had natural phase-selecting function, current differential protection by system operation mode and electric network composition It is always the main protection of various electric pressure transmission lines of electricity.In 500kV and following electric pressure transmission line of electricity, due to power transmission line Curb line capacitance current very little, distribution capacity affects very little to current differential protection performance.However, UHV transmission The voltage of circuit, electric current transmission have obvious wave process, and capacitance current along the line is very big, using two ends current phasor sum Amplitude is faced with current differential protection starting current greatly as the conventional current differential protection of actuating quantity, and in order to prevent protection by mistake Dynamic, improve startup setting value and protection sensitivity can be led to again not enough, govern conventional current differential protection in extra-high voltage transmission line Application on road.

Due to being affected by load current, during high resistance ground short trouble, directly utilize the amplitude of two ends current phasor sum As actuating quantity conventional current differential protection cannot correct tripping fault phase, but by Zero sequence current differential protection as thereafter Standby protection act tripping three-phase line.Because the impact to system stability for the non-full-operating state is much smaller than the feelings of three-phase tripping Condition, can strengthen fault by Zero sequence current differential protection action tripping three-phase line This move strategy and grid stability is rushed Hit.Therefore, during single phase ground fault fault, if can correct tripping fault phase, retain remaining and two normally mutually continue to run with, Be conducive to strengthening the stabilization of power grids, so that the stronger reliability of electrical network.

Content of the invention

It is an object of the invention to overcoming the shortcomings of that prior art exists, one kind is provided to be based on positive sequence Sudden Changing Rate differential factor Matrix extra-high voltage transmission line relay protecting method.The inventive method physical model adopts distributed parameter model, is not subject to distribution capacity The impact of electric current is it is adaptable to any electric pressure, particularly UHV transmission line.The inventive method is applied to UHV transmission Relay protection in the line fault ripple two weeks after time, performance is not affected by transition resistance and load current, especially when When there is single-phase high-impedance in UHV transmission line, the correct reliable recognition fault phase of the inventive method energy, realize single-phase Fault jumps the relay protection function of single-phase fault circuit.

For completing above-mentioned purpose, the present invention adopts the following technical scheme that：

Based on positive sequence Sudden Changing Rate differential factor matrix extra-high voltage transmission line relay protecting method, comprise the following steps：

(1) measure A, B, C phase positive sequence voltage Sudden Changing Rate in m transforming plant protecting installation place for the UHV transmission lineA, B, C phase forward-order current Sudden Changing RateMeasurement UHV transmission Circuit is in A, B, C phase forward-order current Sudden Changing Rate of n transforming plant protecting installation place

(2) utilize A, B, C phase positive sequence voltage Sudden Changing Rate in m transforming plant protecting installation place for the UHV transmission lineA, B, C phase forward-order current Sudden Changing RateCalculate extra-high voltage transmission line Road is in A, B, C phase forward-order current Sudden Changing Rate of n transforming plant protecting installation place

Wherein, γ₁For UHV transmission line positive sequence propagation constant；Z_c1For UHV transmission line positive sequence wave impedance；l_mn For the UHV transmission line length between m transformer station and n transformer station；Cosh (.) is hyperbolic cosine function；Sinh (.) is double Bent SIN function；

(3) calculateCalculate positive sequence Sudden Changing Rate differential factor matrix

(4) choose the greatest member in positive sequence Sudden Changing Rate differential factor matrix SThen basisJust choose Element in sequence Sudden Changing Rate differential factor matrix SWithSet threshold values α, using following relay protection criterion Failure judgement phase line：

If i () meets S_ij>α and S_ik>α, then judge i phase line for fault phase line；

(ii) if meeting S_ij>α and S_kj>α, then judge ik phase line for fault phase line；

(iii) if meeting α>S_ij>1, then judge ijk phase line for fault phase line；Wherein, ijk=ABC, ACB, BAC, BCA, CAB, CBA phase.

The feature of the present invention and technological achievement：

The inventive method physical model adopts distributed parameter model, is not affected it is adaptable to any by capacitance current Electric pressure, particularly UHV transmission line.The inventive method is applied to the UHV transmission line fault ripple two weeks after time Interior relay protection, performance is not affected by transition resistance and load current, especially when UHV transmission line occurs list During phase high resistance earthing fault, the correct reliable recognition fault phase of the inventive method energy, realize single-phase fault and jump single-phase fault circuit Relay protection function.

Brief description

Fig. 1 is the UHV transmission line fault schematic diagram of application the inventive method.

Specific embodiment

Below according to Figure of description, technical scheme is expressed in further detail.

Fig. 1 is the UHV transmission line fault schematic diagram of application the inventive method.

Based on positive sequence Sudden Changing Rate differential factor matrix extra-high voltage transmission line relay protecting method, comprise the following steps：

(1) the fundamental frequency electric parameters in m side transformer station and n side transforming plant protecting installation place for the UHV transmission line are respectively by pacifying Synchronous phasor measurement unit (phase measurement unit, PMU) measurement being contained in transformer station both this obtains.Synchronous phase Phasor measurement unit measures A, B, C phase positive sequence voltage Sudden Changing Rate in m transforming plant protecting installation place for the UHV transmission lineA, B, C phase positive sequence Sudden Changing Rate Measurement UHV transmission line is in n A, B, C phase forward-order current Sudden Changing Rate of transforming plant protecting installation placeMeasurement data is through fiber data Passage sends UHV transmission line protection device to, and UHV transmission line protection device is completed by applying the inventive method Relay protection function：

(2) utilize A, B, C phase positive sequence voltage Sudden Changing Rate in m transforming plant protecting installation place for the UHV transmission lineA, B, C phase forward-order current Sudden Changing RateCalculate extra-high voltage transmission line Road is in A, B, C phase forward-order current Sudden Changing Rate of n transforming plant protecting installation place

Wherein, γ₁For UHV transmission line positive sequence propagation constant；Z_c1For UHV transmission line positive sequence wave impedance；l_mn For the UHV transmission line length between m transformer station and n transformer station；Cosh (.) is hyperbolic cosine function；Sinh (.) is double Bent SIN function.

(3) calculate A, B, C phase positive sequence Sudden Changing Rate difference current amplitude

And then calculate positive sequence Sudden Changing Rate differential factor matrix

(4) choose the greatest member in positive sequence Sudden Changing Rate differential factor matrix SThen basisJust choose Element in sequence Sudden Changing Rate differential factor matrix SWithSet threshold values α, using following relay protection criterion Failure judgement phase line：

If i () meets S_ij>α and S_ik>α, then judge i phase line for fault phase line；

(ii) if meeting S_ij>α and S_kj>α, then judge ik phase line for fault phase line；

(iii) if meeting α>S_ij>1, then judge ijk phase line for fault phase line；Wherein, ijk=ABC, ACB, BAC, BCA, CAB, CBA phase.

The inventive method physical model adopts distributed parameter model, is not affected it is adaptable to any by capacitance current Electric pressure, particularly super-high-voltage/ultra-high-voltage.The inventive method is applied to UHV transmission line fault two weeks after Relay protection in the ripple time, performance is not affected by transition resistance and load current, especially works as UHV transmission line When there is single-phase high-impedance, the correct reliable recognition fault phase of the inventive method energy, realize single-phase fault and jump single-phase fault The relay protection function of circuit.

The foregoing is only the preferred embodiment of the present invention, but protection scope of the present invention is not limited thereto, appoint What those familiar with the art the invention discloses technical scope in, the change or replacement that can readily occur in, all Should be included within the scope of the present invention.

Claims (1)

1. it is based on positive sequence Sudden Changing Rate differential factor matrix extra-high voltage transmission line relay protecting method it is characterised in that including following Step：

(1) measure A, B, C phase positive sequence voltage Sudden Changing Rate in m transforming plant protecting installation place for the UHV transmission lineA, B, C phase forward-order current Sudden Changing Rate Measurement extra-high voltage transmission line Road is in A, B, C phase forward-order current Sudden Changing Rate of n transforming plant protecting installation place

(2) utilize A, B, C phase positive sequence voltage Sudden Changing Rate in m transforming plant protecting installation place for the UHV transmission lineA, B, C phase forward-order current Sudden Changing Rate Calculate extra-high voltage transmission line Road is in A, B, C phase forward-order current Sudden Changing Rate of n transforming plant protecting installation place

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

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

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

Wherein, γ₁For UHV transmission line positive sequence propagation constant；Z_c1For UHV transmission line positive sequence wave impedance；l_mnBecome for m UHV transmission line length between power station and n transformer station；Cosh (.) is hyperbolic cosine function；Sinh (.) is hyperbolic sine Function；

(3) calculate $I_{\mathrm{dA}1}=|\mathrm{\Δ}{\stackrel{\·}{I}}_{\mathrm{mnA}1}+{\mathrm{\Δ}\stackrel{\·}{I}}_{\mathrm{nA}1}|,I_{\mathrm{dB}1}=|\mathrm{\Δ}{\stackrel{\·}{I}}_{\mathrm{mnB}1}+\mathrm{\Δ}{\stackrel{\·}{I}}_{\mathrm{nB}1}|,I_{\mathrm{dC}1}=|\mathrm{\Δ}{\stackrel{\·}{I}}_{\mathrm{mnC}1}+\mathrm{\Δ}{\stackrel{\·}{I}}_{\mathrm{nC}1}|,$ Calculate positive sequence mutation Amount 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 positive sequence Sudden Changing Rate differential factor matrix SThen basisChoose positive sequence to dash forward Element in variable differential factor matrix SWithSet threshold values α, judged using following relay protection criterion Fault phase line：

If i () meets S_ij>α and S_ik>α, then judge i phase line for fault phase line；

(ii) if meeting S_ij>α and S_kj>α, then judge ik phase line for fault phase line；

(iii) if meeting α>S_ij>1, then judge ijk phase line for fault phase line；Wherein, ijk=ABC, ACB, BAC, BCA, CAB, CBA phase.