CN101359822A - Transmission line single-phase adaptive reclosing implementing method based on fault point voltage - Google Patents

Abstract

The invention belongs to electric power system transmission line relay protection field and relates to a method for judging failure property of single-phase self-adapting reclosing based on fault point voltage: real-timely acquiring the voltage and current value of every phase on one side of the transmission line; measuring failure distance; real-timely computing the current actual fault point voltage; finding out the sound phase current and fault phase voltage at the two ends of the line, then finding out the approximate open circuit voltage of the fault point and the set-pressure using the result of sound phase current and fault phase voltage and the result of failure distance measurement; comparing the fault point voltage with the set pressure, an instantaneous failure is judged if the fault point voltage value is persistently larger than the set pressure within the set time period after single phase tripping, and the protection sends out a reclosing order after certain time delay; a permanent failure is judged if the fault point voltage value is always smaller than the set pressure within the set time period, and the protection will not reclose after tripping off the three phase line. The invention can ensure the persistency and stability of system power supply and avoid the damage by single phase reclosing and permanent failure to electric equipment.

Description

Transmission line single-phase adaptive reclosing implementation method based on fault point voltage

Technical field

The invention belongs to power system transmission line relaying protection field, be specifically related to a kind of power system transmission line automatic reclosing implementation method.

Background technology

The fault that takes place on the high-tension overhead line is instantaneity mostly, overlapping the circuit tripping after the blow-out of fault point is the normal operation of restorable system mutually, therefore, can power the extensive use in high-voltage fence of automatic reclosing technology continually and steadily for the guarantee electric power system.Yet the auto recloser of current practical application all blindly overlaps behind circuit breaker trip, can not carry out the judgement of transient fault and permanent fault.In case the permanent fault of coinciding with, normal power supply that not only can not recovery system, and the secondary pulse that coincides with fault once more and caused to electric equipment, infringement that will be when being short-circuited under the normal operating condition, even also may destroy the stability of electric power system paired running, cause system oscillation, even disintegrate, cause large-area power-cuts.Overlap the harm that causes in order to solve above-mentioned blindness, industry is seeking to avoid coinciding with the method for permanent fault always, therefore, can judge and selects the adaptive reclose of coincidence to be subjected to extensive concern nature of trouble.Operating experience shows that in all kinds of faults that the ultrahigh voltage power circuit takes place, single phase ground fault accounts for 70%～80%, and research single-phase adaptive reclosing device has great practical significance.

The main task of single-phase adaptive auto recloser is exactly the information of utilizing behind the line tripping, and nature of trouble is effectively discerned, and judged result be if transient fault can overlap, if permanent fault then tripping three-phase and locking overlap.So just avoid the blindness of traditional single phase automatic reclosing when overlapping, guaranteed the reliability and stability of electrical network under various nature of troubles.

The single-phase adaptive reclosing technical development has obtained many theoretical results for over ten years, and voltage magnitude criterion etc. is wherein typically arranged.These criterions all are to use circuit tripping phase terminal voltage to carry out the judgement of nature of trouble, generally are applicable to the single-phase adaptive COINCIDENCE PROBLEMS that solves no shunt reactor compensated line.And for the heavy load long distance transmission line, line mutual-inductance voltage is very big, causes the probability of erroneous judgement will be very big; For the circuit of band shunt reactor compensation, the compensation effect of shunt reactor makes that fault phase recovery voltage is very little, so also there is the possibility of erroneous judgement in voltage criterion; When the transition grounding through resistance, also may cause erroneous judgement in the fault point.Need to study the reliable more comprehensively wider single-phase adaptive reclosing nature of trouble determination methods of accommodation of invention for this reason.

Summary of the invention

The present invention overcomes the defective of existing single-phase adaptive reclosing technology, propose a kind ofly can guarantee that transmission line both sides circuit breakers can judge nature of trouble before overlapping accurately, reclosing quick acting when realizing transient fault, the transmission line automatic reclosing of reclosing block during permanent fault, thereby the continuation and the stability of the power supply of assurance system are avoided the single-phase damage that permanent fault causes electric equipment that coincides with.The present invention adopts following technical scheme:

A kind of transmission line single-phase adaptive reclosing implementation method based on fault point voltage, after transmission line generation single-phase fault makes the single-phase tripping operation of circuit both sides circuit breaker, carry out the following step:

(1) gathers each phase voltage and the current value of transmission line one side in real time;

(2) fault localization;

(3) use the fault point voltage that the uniform transmission line equation calculates current reality in real time;

(4) perfect phase both end voltage value and fault two ends current value mutually according to circuit, that utilizes that total track length uniform transmission line equation obtains the circuit two ends perfects phase current and fault phase voltage, utilizes this result and fault localization result to obtain the approximate open circuit voltage of fault point again;

(5) described approximate open circuit voltage be multiply by the dividing potential drop coefficient and the safety factor of maximum transition resistance, try to achieve the voltage of adjusting in real time;

(6) fault point voltage and the voltage of adjusting are made comparisons, if in the setting-up time section after single-phase tripping operation, the fault point voltage value can continue then to be judged to be transient fault greater than setting value, protection is sent out after certain time-delay and is overlapped order; If can not then be judged to be permanent fault greater than setting value all the time in the setting-up time section, protection is with tripping of circuit three-phase and no longer coincidence.

The above-mentioned transmission line single-phase adaptive reclosing implementation method based on fault point voltage, in the step (6), the size of setting-up time section can be between 1/8～1/4 power frequency cycle.

The invention solves the defective that automatic reclosing blindly overlaps, realized the reliable recognition of transient fault and permanent fault.Compared with prior art, this method is applied widely, can be applied to various line lengths and loading condition, and be not subjected to circuit whether with the restriction of shunt reactor, considered the influence of transition resistance, make the reclosing function obtain maximum performance, ensured the stability and the reliability of mains supply to greatest extent, avoided the single-phase damage that permanent fault causes electric equipment that coincides with.

Description of drawings

Fig. 1 is single-phase through transition grounding through resistance fault lumped parameter equivalent network (ignoring line impedance) for circuit.

Fig. 2 for through transition grounding through resistance fault see from the fault point into thevenin equivalent circuit.

Preferred forms

The present invention reliably distinguishes the nature of trouble of transmission line by the line fault point voltage being asked for and being compared with setting value, realizes the self adaptation action of single-pole reclosing.Its specific implementation step is as follows: the first step, ask for fault point voltage.After the generation single-phase fault makes the single-phase tripping operation of circuit both sides circuit breaker on the transmission line,, use the fault point voltage that the uniform transmission line equation calculates current reality in real time at first according to the real-time voltage current sampling data and the fault localization result of circuit one side; In second step, determine real-time setting value.Perfect phase both end voltage and fault two ends electric current (be zero this moment) mutually according to circuit, perfect phase current and fault phase voltage with what total track length uniform transmission line equation was obtained the circuit two ends, utilize this result and fault localization result to obtain the approximate open circuit voltage of fault point again and multiply by the dividing potential drop coefficient of maximum transition resistance and certain safety factor as the voltage of adjusting in real time.The 3rd step, failure judgement character.The fault point voltage and the voltage of adjusting are made comparisons, if can continue within a certain period of time then to be judged to be transient fault greater than setting value from a certain moment, protection be sent out after certain time-delay and is overlapped order; If in setting-up time (the big I of setting-up time is between 1/8～1/4 power frequency cycle), can not then be judged to be permanent fault greater than setting value all the time, protection is with tripping of circuit three-phase and no longer coincidence.

Protected operation equation of the present invention and operating criterion provide as follows:

$\left|{\stackrel{\&CenterDot;}{U}}_f\right|<U_{\mathrm{DZ}}---\left(1\right)$

$U_{\mathrm{DZ}}=k_k\&CenterDot;k_R\&CenterDot;\left|{\stackrel{\&CenterDot;}{U}}_{f\&CenterDot;\mathrm{open}}\right|---\left(2\right)$

The foundation that failure criterion of the present invention proposes at first is described below, single-phase adaptive reclosing permanent fault decision technology scheme of the present invention further is described in conjunction with specific embodiments again.

(1). the proposition of single-pole reclosing fault point voltage amplitude criterion

Suppose permanent single phase ground fault takes place in the circuit, if transition resistance is zero, then fault point voltage is zero; And if transient fault takes place in the circuit, fault point voltage is higher after the blow-out, therefore available fault point voltage is effectively distinguished permanent and instantaneity single phase ground fault.

When having the permanent single phase ground fault of transition resistance in the circuit, fault point voltage can increase with the increase of transition resistance; Have at circuit under the situation of load, its fault point voltage of different abort situation also has a great difference.Therefore, need select suitable operation voltage at different circuit ruuning situation and failure condition, with sensitivity and the reliability of guaranteeing that criterion is enough.Relation when analyzing permanent fault and transient fault under the various fault types between the fault point voltage proposes the determination methods of nature of trouble.

For permanent single phase ground fault, equivalent network behind the transition grounding through resistance such as Fig. 1 after the circuit breaker tripping of fault phase two ends, can be considered as the equivalent network between fault point and the ground, the built-in system equivalence is the series connection of voltage source and impedance, and equivalent electric circuit as shown in Figure 2.

The equivalent voltage source size is the open circuit voltage of fault point ground connection branch road, the fault point voltage when being transient fault.

${\stackrel{\&CenterDot;}{U}}_{\mathrm{eq}}={\stackrel{\&CenterDot;}{U}}_{f\&CenterDot;\mathrm{open}}---\left(3\right)$

Equiva lent impedance see from the fault point when the internal system voltage source is changed to zero into equivalent earth impedance.After the circuit breaker tripping of fault phase both sides, fault is got in touch by line capacitance and mutual inductance between mutually with sound, owing to the capacitive reactance of circuit much larger than impedance, ignore line impedance after, equivalent earth impedance is a steady state value, can replace with the equivalent capacitance to earth of tripping phase.During all kinds fault, tripping is at the equivalent earth impedance Z at place, fault point _EqComputing formula is as follows:

$Z_{\mathrm{eq}}=Y_{\mathrm{eq}}^{-1}---\left(4\right)$

Y _eq＝Y _s (5)

The equivalent admittance that is the place, fault point is the self-admittance of faulty line.

Permanent fault is fault point voltage when the transition grounding through resistance

With inner equivalent voltage source Between satisfy:

${\stackrel{\&CenterDot;}{U}}_f^{\&prime;}=\frac{R_g}{R_g+Z_{\mathrm{eq}}}{\stackrel{\&CenterDot;}{U}}_{\mathrm{eq}}---\left(6\right)$

k _R∠ θ is the dividing potential drop coefficient of fault transition resistance.

$k_R=\frac{R_g}{\sqrt{{R^2}_g+{Z^2}_{\mathrm{eq}}}},\mathrm{\&theta;}=\arg \left(\frac{R_g}{R_g-j{Z}_{\mathrm{eq}}}\right)---\left(7\right)$

By above derivation as can be known, if the open circuit voltage of fault point ground connection branch road under the known current failure condition, the inside equivalent voltage source voltage of fault point equivalent network in the time of just can trying to achieve permanent fault, it is as follows to calculate permanent fault voltage of fault point when the transition grounding through resistance by formula (6):

After single phase ground fault takes place in the circuit, by the line scan pickup coil side voltage and current can be regarded as the physical fault point voltage

Get fault point voltage under the situation (the 500kV electric pressure is got 300 Ω) of transition resistance maximum as setting value, can judge the permanent fault of band transition resistance accurately.It is as follows to provide criterion:

$\left|{\stackrel{\&CenterDot;}{U}}_f\right|<U_{\mathrm{DZ}}---\left(9\right)$

$U_{\mathrm{DZ}}=k_k\&CenterDot;k_R\&CenterDot;\left|{\stackrel{\&CenterDot;}{U}}_{\mathrm{tran}}\right|---\left(10\right)$

k _kBe safety factor, desirable 1.1～1.3.

(2). the acquiring method of fault point voltage

No matter single-phase transient fault or permanent fault can be carried out asking for of fault point voltage by the following method.

At first, each phase terminal voltage and electric current phasor in the protection are become modulus by phase-model transformation.Be convenience of calculation, adopt the Karranbauer conversion here, transformation matrix is as follows:

$S=\frac{1}{3}\left[\begin{array}{ccc}1& 1& 1\\ 1& -1& 0\\ 1& 0& -1\end{array}\right]$ $S^{-1}=\frac{1}{3}\left[\begin{array}{ccc}1& 1& 1\\ 1& -2& 1\\ 1& 0& -2\end{array}\right]$

${\stackrel{\&CenterDot;}{U}}_{0\mathrm{\&alpha;\&beta;}}={S\stackrel{\&CenterDot;}{U}}_{\mathrm{ABC}}---\left(11\right)$

${\stackrel{\&CenterDot;}{I}}_{0\mathrm{\&alpha;\&beta;}}=S{\stackrel{\&CenterDot;}{I}}_{\mathrm{ABC}}---\left(12\right)$

The impedance matrix conversion is as follows:

Z _0αβ＝S ^-1Z _ABCS (13)

After the conversion, impedance matrix is full decoupled.

The admittance matrix conversion is as follows:

Y _0αβ＝S ^-1Y _ABCS (14)

After the conversion, admittance matrix is full decoupled.

The propagation constant and the wave impedance of circuit different modulus are as follows:

${\mathrm{\&gamma;}}_0=\sqrt{Z_0{Y}_0},$ ${\mathrm{\&gamma;}}_{\mathrm{\&alpha;}}=\sqrt{Z_{\mathrm{\&alpha;}}{Y}_{\mathrm{\&alpha;}}},$ ${\mathrm{\&gamma;}}_{\mathrm{\&beta;}}=\sqrt{Z_{\mathrm{\&beta;}}{Y}_{\mathrm{\&beta;}}}---\left(15\right)$

$Z_{c0}=\sqrt{Z_0/Y_0},$ $Z_{\mathrm{c\&alpha;}}=\sqrt{Z_{\mathrm{\&alpha;}}/Y_{\mathrm{\&alpha;}}},$ $Z_{\mathrm{c\&beta;}}=\sqrt{Z_{\mathrm{\&beta;}}/Y_{\mathrm{\&beta;}}}---\left(16\right)$

Known line head end (m side) voltage and current amount is l place when breaking down apart from m side length on the circuit then, and the voltage of fault point is:

$\left\{\begin{array}{c}{\stackrel{\&CenterDot;}{U}}_{f0}={\stackrel{\&CenterDot;}{U}}_{m0}\cosh {\mathrm{\&gamma;}}_{0}l-Z_{c0}{\stackrel{\&CenterDot;}{I}}_{m0}{\sinh \mathrm{\&gamma;}}_{0}l\\ {\stackrel{\&CenterDot;}{U}}_{\mathrm{f\&alpha;}}={\stackrel{\&CenterDot;}{U}}_{\mathrm{m\&alpha;}}{\cosh \mathrm{\&gamma;}}_{a}l-Z_{\mathrm{c\&alpha;}}{\stackrel{\&CenterDot;}{I}}_{\mathrm{m\&alpha;}}{\sinh \mathrm{\&gamma;}}_{\mathrm{\&alpha;}}l\\ {\stackrel{\&CenterDot;}{U}}_{\mathrm{f\&beta;}}={\stackrel{\&CenterDot;}{U}}_{\mathrm{m\&beta;}}{\cosh \mathrm{\&gamma;}}_{\mathrm{\&beta;}}l-Z_{\mathrm{c\&beta;}}{\stackrel{\&CenterDot;}{I}}_{\mathrm{m\&beta;}}{\sin \mathrm{\&gamma;}}_{\mathrm{\&beta;}}l\end{array}\right.---\left(17\right)$

The fault point voltage and the electric current (summary) that in like manner can write out known line end (n side) voltage and current and calculate.

Fault point voltage is carried out the Karranbauer inverse transformation, can try to achieve each phase fault point voltage.

${\stackrel{\&CenterDot;}{U}}_{\mathrm{fABC}}=S^{-1}\&CenterDot;{\stackrel{\&CenterDot;}{U}}_{f0\mathrm{\&alpha;\&beta;}}---\left(18\right)$

For band shunt reactor circuit, can flow through electric current on the shunt reactor, the electric current of using when therefore calculating fault point voltage should be the line scan pickup coil side electric current and deducts the electric current that flows through on the shunt reactor, and formula is as follows:

$\left\{\begin{array}{c}{\stackrel{\&CenterDot;}{I}}_{m0}^{\&prime;}={\stackrel{\&CenterDot;}{I}}_{m0}-{\stackrel{\&CenterDot;}{U}}_{m0}/(X_L+3X_N)\\ {\stackrel{\&CenterDot;}{I}}_{\mathrm{m\&alpha;}}^{\&prime;}={\stackrel{\&CenterDot;}{I}}_{\mathrm{m\&alpha;}}-{\stackrel{\&CenterDot;}{U}}_{\mathrm{m\&alpha;}}/X_L\\ {\stackrel{\&CenterDot;}{I}}_{\mathrm{m\&beta;}}^{\&prime;}={\stackrel{\&CenterDot;}{I}}_{\mathrm{m\&beta;}}-{\stackrel{\&CenterDot;}{U}}_{\mathrm{m\&beta;}}/X_L\end{array}\right.---\left(19\right)$

X _LAnd X _NBe respectively the reactance value of shunt reactor and the little reactance of neutral point.

N side electric current also can adopt with quadrat method and obtain.The electric current of obtaining with following formula is brought into formula (17), can obtain the fault point voltage of band shunt reactor circuit.

(3). the acquiring method of real-time setting value

The setting value of this criterion adopts floating threshold, adjusts in real time at the ruuning situation that circuit is different, and its method is as follows.

After line fault trips mutually, it is very little that the voltage that perfects phase is influenced by nature of trouble, therefore, when asking the open circuit voltage of fault point ground connection branch road, can disconnect by assumed fault point ground connection branch road, so just can current perfect phase both end voltage and fault mutually two ends electric current (being zero) perfect phase current and fault phase voltage as known quantity with what the uniform transmission line equation of total track length (L) can be obtained under this kind hypothesis circuit two ends:

$\left[\begin{array}{cccc}{\stackrel{\&CenterDot;}{U}}_{\mathrm{mGZ},}^{\&prime;}& {\stackrel{\&CenterDot;}{U}}_{\mathrm{mJQ},}& {\stackrel{\&CenterDot;}{I}}_{\mathrm{mGZ},}^{\&prime;}& {\stackrel{\&CenterDot;}{I}}_{\mathrm{mJQ}}\end{array}\right]=\left[\mathrm{TL}\right]\left[\begin{array}{cccc}{\stackrel{\&CenterDot;}{U}}_{\mathrm{nGZ},}^{\&prime;}& {\stackrel{\&CenterDot;}{U}}_{\mathrm{nJQ},}& {\stackrel{\&CenterDot;}{I}}_{\mathrm{nGZ}},& {\stackrel{\&CenterDot;}{I}}_{\mathrm{nJQ}}^{\&prime;}\end{array}\right]---\left(20\right)$

Be transformed to:

$\left[\begin{array}{cccc}{\stackrel{\&CenterDot;}{U}}_{\mathrm{mGZ}}^{\&prime;},& {\stackrel{\&CenterDot;}{I}}_{\mathrm{mJQ}}^{\&prime;},& {\stackrel{\&CenterDot;}{U}}_{\mathrm{nGZ}}^{\&prime;},& {\stackrel{\&CenterDot;}{I}}_{\mathrm{nJQ}}^{\&prime;}\end{array}\right]=\left[\mathrm{TP}\right]\left[\begin{array}{cccc}{\stackrel{\&CenterDot;}{I}}_{\mathrm{mGZ}},& {\stackrel{\&CenterDot;}{U}}_{\mathrm{mJQ}},& {\stackrel{\&CenterDot;}{I}}_{\mathrm{nGZ}},& {\stackrel{\&CenterDot;}{U}}_{\mathrm{nJQ}}\end{array}\right]---\left(21\right)$

The left side is a unknown quantity, and the right is a known quantity.

Utilize the voltage and current amount of the either side after calculating and known range finding result, can obtain the open circuit voltage of fault point.

$\left[\begin{array}{cccc}{\stackrel{\&CenterDot;}{U}}_{\mathrm{fGZ},}& {\stackrel{\&CenterDot;}{U}}_{\mathrm{fJQ},}& {\stackrel{\&CenterDot;}{I}}_{\mathrm{fGZ}},& {\stackrel{\&CenterDot;}{I}}_{\mathrm{fJQ}}\end{array}\right]=\left[\mathrm{Tl}\right]\left[\begin{array}{cccc}{\stackrel{\&CenterDot;}{U}}_{\mathrm{mGZ},}^{\&prime;}& {\stackrel{\&CenterDot;}{U}}_{\mathrm{mJQ},}& {\stackrel{\&CenterDot;}{I}}_{\mathrm{mGZ}}^{\&prime;},& {\stackrel{\&CenterDot;}{I}}_{\mathrm{mJQ}}\end{array}\right]---\left(22\right)$

The same with the fault point voltage formula, under calculating band shunt reactor circuit transient fault, during fault point voltage, notice that used line scan pickup coil side electric current will deduct the electric current that flows through on the shunt reactor.

No matter current is the fault of which kind of character, more than the fault point open circuit voltage and the physical fault point open circuit voltage of hypothesis calculating gained are very approaching.Multiply by certain safety factor with this fault point open circuit voltage,, eliminated of the influence of circuit running status, guarantee that this criterion all has enough reliabilities and sensitivity under various loading conditions criterion as the setting value of criterion.

Above content only is embodiments of the invention, and its purpose is not the restriction that is used for system and method proposed by the invention, and protection scope of the present invention is as the criterion with claim.Those skilled in the art all should drop within protection scope of the present invention its all conspicuous modification or variation about form and details of carrying out under the situation that does not depart from scope and spirit of the present invention.

Claims (2)

1. transmission line single-phase adaptive reclosing implementation method based on fault point voltage, after transmission line generation single-phase fault makes the single-phase tripping operation of circuit both sides circuit breaker, carry out the following step:

(1) gathers each phase voltage and the current value of transmission line one side in real time;

(2) fault localization;

(3) use the fault point voltage that the uniform transmission line equation calculates current reality in real time;

(4) perfect phase both end voltage value and fault two ends current value mutually according to circuit, that utilizes that total track length uniform transmission line equation obtains the circuit two ends perfects phase current and fault phase voltage, utilizes this result and fault localization result to obtain the approximate open circuit voltage of fault point again;

(5) described approximate open circuit voltage be multiply by the dividing potential drop coefficient and the safety factor of maximum transition resistance, try to achieve the voltage of adjusting in real time;

(6) fault point voltage and the voltage of adjusting are made comparisons, if in the setting-up time section after single-phase tripping operation, the fault point voltage value can continue then to be judged to be transient fault greater than setting value, protection is sent out after certain time-delay and is overlapped order; If can not then be judged to be permanent fault greater than setting value all the time in the setting-up time section, protection is with tripping of circuit three-phase and no longer coincidence.

2. the transmission line single-phase adaptive reclosing implementation method based on fault point voltage according to claim 1 is characterized in that in the step (6), the size of described setting-up time section is between 1/8～1/4 power frequency cycle.

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