CN104242262B - A kind of quick bus bar protecting method based on fault component average product - Google Patents

Abstract

The invention discloses a kind of quick bus bar protecting method based on fault component average product, its detailed process includes：1) voltage and current at each outlet bus protection element that Real-time Collection is connected with bus；2) phase-model transformation is carried out to fault component voltage and current, respective Aerial mode component is extracted；3) product of the average of line mode voltage and line mould electric current is calculated；Using the positive and negative as the foundation for judging positive failure and reverse fault of average product；Using the fault direction of all outlets differentiate result as judge bus whether the foundation of failure；The method uses phase-model transformation, the feature construction bus protection criterion accumulated using the average of fault component line mode voltage and fault component line mould electric current, and with simplicity, sensitivity is high, quick action, and identification is accurate, it is easy to the advantage of Project Realization.

Description

A kind of quick bus bar protecting method based on fault component average product

Technical field

The present invention relates to a kind of quick bus bar protecting method based on fault component average product.

Background technology

The strong intelligent grid for building cleaning, safety, self-healing, economy, high-quality and interaction is the hair of grid automation technology Exhibition direction and inexorable trend.Transformer station carries connecting line as the critical support point and the node of electric power networks of intelligent grid Road, electric energy is conveyed, changed voltage class, collected electric current, distribution electric current, control power flow, the adjustment function such as voltage.Therefore, The safe and reliable operation of power network is heavily dependent on the reliability of substation equipment and system.Connection generator, transformer, The substation bus bar of the equipment such as transmission line of electricity and load as power system one of critical elements, be power system power transmission and distribution Hinge.If broken down on bus, bus protection must quickly cut off all elements being connected thereto, fault incidence Greatly, and busbar protective device tripping or malfunction may cause serious consequence to whole power system.As power system is advised Expanding day by day for mould and constantly increasing for voltage class, configure quick, sensitive and high reliability bus protection and seem particularly heavy Will.

Divided according to structure, bus protection is broadly divided into two major classes：Centralization protection and distributed protection.It is former according to protection Reason is divided, and bus protection mainly has the protection based on power frequency amount and the major class of the protection based on transient two.It is widely used at present Bus protection is the current differential protection based on power frequency amount, but such method requires the current sampling data stringent synchronization of each outlet. Additionally, protective value is also easily influenceed by CT saturations with the factor such as out of proportion.To eliminate the influence of CT saturations, protection is improved Responsiveness and reliability, domestic and foreign scholars have carried out a series of research, and achieve some beneficial achievements.

《Asynchronous method CT saturation differentiates new principle and its application》Propose the electricity suitable for PC bus protection The detection method of current transformer saturation, i.e., the first half-wave method for synchronously recognizing of first cycle use after failure generation, and After failure occurs and when differential protection is not acted, recognized using harmonic braking locking.The program is still fitted to conversion hysteria failure With and be successfully applied to engineering reality, but actuation time is no less than 20ms.

《Bus protection new principle based on transient current spectrum energy》Propose a kind of mother based on transient current spectrum energy Line protects new principle, and spectrum energy of the principle by relatively more each transient high frequency electric current in a timing window can be realized in bus area Effective differentiation of outer failure, the method quick action and is not influenceed by CT saturations, but small initial angle failure is by serious shadow Ring the sensitivity to the guard method and reliability.

《A busbar protection technique and its performance during CT saturation and CT ratio-mismatch》Using the positive and negative sequence corresponding to each loop power frequency fault component on bus Quadrant where the phase angle of equiva lent impedance distinguishes bus internal fault external fault.Simulation result shows that the method does not receive CT saturations, CT The influence of ratio mismatch, and do not influenceed by sample frequency, but responsiveness is slower.

《Bus protection based on neural network model》Propose a kind of bus bar protecting method based on neural network model. The method can adaptive CT characteristic be inconsistent, bus running manner changes and the situation of CT broken strings, and identification internal fault external fault is just True rate is higher, but neural network structure is complicated, need to largely be trained, and operand is big, and practicality is not strong.

《Using the decentralized bus protection of circuit transient state travelling wave power direction》Using the side of each circuit transient state travelling wave power To construction criterion, the method action is fast and reliable, is not influenceed by fault type, fault resistance etc. substantially, but voltage Protection can not be recognized correctly when zero crossing occurs singlephase earth fault.

《Bus protection principle based on model and parameters identification》By the identification to fault equivalence inductive circuit model parameter And the calculating of parameter discrete degree, inside and outside portion's failure and external fault CT saturation states of bus can be accurately judged to, so as to constitute Bus protection criterion with self adaptation braking characteristic.The principle need not set special CT saturation detection elements, and need not Filtering, responsiveness is very fast, but sensitivity decrease during bus troubles inside the sample space.

《A travelling-wave-based amplitude integral busbar protection technique》A kind of traveling wave amplitude integration bus protection new principle is proposed, by calculating direct wave and backward-travelling wave amplitude Ratio relation realize the differentiation of failure inside and outside bus, the principle is not by CT saturations, fault initial angle and fault ground resistance etc. The influence of factor, but the principle sample frequency is up to 100kHz, and the sample frequency of combining unit is general in intelligent substation It is 4kHz, is difficult Project Realization.

《Bus protection new method based on measurement wave impedance》Propose a kind of bus protection based on measurement wave impedance new Method, when there is bus troubles inside the sample space, the polarity of the measurement wave impedance of all circuits is negative, amplitude approximately equal；Work as mother When line occurs out-of-area line road failure, the polarity of the measurement wave impedance of faulty line is for just, and its amplitude is much smaller than non-fault line Measurement wave impedance amplitude.The method has reliability and very strong adaptability very high, but sample frequency is high and bus knot Structure has a certain impact to measurement wave impedance tool.

As can be seen here, the existing research on bus protection, not economical and practical, quick action and sensitive completely Degree method high.

The content of the invention

The present invention is in order to solve the above problems, it is proposed that a kind of quick bus protection side based on fault component average product Method, the method is Bu Tong special in internal fault external fault with the average product of fault component line mould electric current using fault component line mode voltage Structure bus protection criterion is levied, with simplicity, sensitivity is high, quick action, identification is accurate, it is easy to the advantage of Project Realization.

To achieve these goals, the present invention is adopted the following technical scheme that：

A kind of quick bus bar protecting method based on fault component average product, comprises the following steps：

(1) voltage and current at each outlet bus protection element that Real-time Collection is connected with bus；

(2) after the voltage and current filtering that will be gathered, phase-model transformation is carried out to power frequency fault component voltage and current, is extracted The Aerial mode component of fault component voltage and current；

(3) product of line mode voltage average and line mould electric current average is calculated, using the positive and negative as the positive event of judgement of average product The foundation of barrier and reverse fault, then using the fault direction of all outlets differentiate result as judge bus whether the foundation of failure, Specific differentiation includes：It is positive event if the modulus average product code detected by certain the bus protection unit of outlet is negative Barrier；If it is reverse fault just that the modulus average product code detected by certain the bus protection unit of outlet is；If with bus Connected each branch road bus protection unit is determined as reverse direction failure, then be bus-bar fault.

In the step (2), the full voltage and total current that will be collected first are filtered after load component filters high fdrequency component again Obtain power frequency fault component.

In the step (2), the concrete mode of phase-model transformation is：

In formula, f_a、f_bAnd f_cIt is fault component voltage or fault component electric current, the 1 mold component f that conversion is obtained₁With 2 moulds point Amount f₂All fault types, f can be reflected₀It is 0 mold component.

In the step (3), specific basis for estimation is：

1) with the line mode voltage average of certain outlet and the product S of line mould electric current average_m=ave (Δ u_m(t))×ave(Δ i_m(t)) it is positive and negative as identification fault direction criterion, in formula, ave (Δ u_m(t)) and ave (Δ i_m(t)) be respectively and bus The m articles connected fault component of outlet is through the line mode voltage after phase-model transformation and the average of line mould electric current, S_mIt is the m articles outlet Line mode voltage and line mould electric current average product, if S_mJust, to be then determined as reverse fault, if S_mIt is negative, then is determined as positive event Barrier；

2) calculateIn formula, sign (S_m) it is S_mSymbol, it is stipulated that work as S_m>When 0, sign (S_m)=1；When S_mWhen=0, sign (S_m)=0；Work as S_m<When 0, sign (S_m)=- 1, if formulaSet up, be then determined as Bus-bar fault；Otherwise, bus is normal, and n represents the total number of the outlet being connected with bus.

The basis for estimation 2) in, the outlet being connected with bus includes transformer branch and circuit.

In the step (3), failure positive direction is that bus points to outlet.

Beneficial effects of the present invention are：

(1) a half breaker bus connection type to single busbar and complexity can reliably be applicable, and sample frequency is intelligence 4 kHz of energy transformer station combining unit requirement, with stronger adaptability；

(2) it is reliable under various failure primary condition, rapidly recognize fault direction, substantially by fault initial angle, therefore The influence of the factors such as barrier earth resistance, fault type, sensitivity is high, quick action；

(3) during CT saturations protection will not malfunction, with reliability very high；

(4) recognition methods principle is simple, clear, and identification is accurate, it is easy to Project Realization.

Brief description of the drawings

Fig. 1 is simple substation bus bar structure failure schematic diagram；

Super-imposed networks when Fig. 2 is bus generation three-phase shortcircuit；

Protection location R when Fig. 3 (a) is bus-bar fault₁Detect the fault component and average product waveform during θ=0 °；

Protection location R when Fig. 3 (b) is bus-bar fault₁Detect the fault component and average product waveform during θ=30 °；

Protection location R when Fig. 3 (c) is bus-bar fault₁Detect the fault component and average product waveform during θ=90 °；

Protection location R when Fig. 3 (d) is bus-bar fault₁Detect the fault component and average product waveform during θ=240 °；

Fig. 4 is circuit l₁Upper f₁There are super-imposed networks during three-phase shortcircuit in place；

Fig. 5 (a) is circuit l₁R during failure₁Detect the fault component and average product waveform during θ=0 °；

Fig. 5 (b) is circuit l₁R during failure₁Detect the fault component and average product waveform during θ=30 °；

Fig. 5 (c) is circuit l₁R during failure₁Detect the fault component and average product waveform during θ=90 °；

Fig. 5 (d) is circuit l₁R during failure₁Detect the fault component and average product waveform during θ=240 °；

Fig. 6 is bus internal fault external fault identification process block diagram；

Fig. 7 is 500 kV bus simulation models；

Fig. 8 (a) is l₃I mothers CT during failure₁The B phase current waveform figures of outlet；

Fig. 8 (b) is l₃I mothers CT during failure₃B phase currents (saturation) oscillogram of outlet；

Fig. 8 (c) is l₃I mothers CT during failure₅The B phase current waveform figures of outlet；

Fig. 9 (a) is l₃II mothers CT during failure₂B phase currents (the CT of outlet₃B phases saturation)；

Fig. 9 (b) is l₃II mothers CT during failure₄B phase currents (the CT of outlet₃B phases saturation)；

Fig. 9 (c) is l₃II mothers CT during failure₆B phase currents (the CT of outlet₃B phases saturation)；

Figure 10 (a) is l₃I female A phase difference currents (CT during failure₃B phases saturation)；

Figure 10 (b) is l₃I female B phase difference currents (CT during failure₃B phases saturation)；

Figure 10 (c) is l₃I female C phase difference currents (CT during failure₃B phases saturation)；

Figure 11 (a) is l₃II female A phase difference currents (CT during failure₃B phases saturation)；

Figure 11 (b) is l₃II female B phase difference currents (CT during failure₃B phases saturation)；

Figure 11 (c) is l₃II female C phase difference currents (CT during failure₃B phases saturation)；

Figure 12 (a) is l₃The line mode voltage component waveform figure (CT that I female each protection location is detected during failure₃B phases satisfy With)；

Figure 12 (b) is l₃The line mould current component wave form figure (CT that I female each protection location is detected during failure₃B phases satisfy With)；

Figure 13 (a) is l₃The line mode voltage component waveform figure (CT that II female each protection location is detected during failure₃B phases satisfy With)；

Figure 13 (b) is l₃The line mould current component wave form figure (CT that II female each protection location is detected during failure₃B phases satisfy With).

Specific embodiment：

The invention will be further described with embodiment below in conjunction with the accompanying drawings.

As shown in fig. 6, a kind of quick bus bar protecting method based on fault component average product, comprises the following steps：

(1) voltage and current at each outlet bus protection element that Real-time Collection is connected with bus；

(2) phase-model transformation is carried out after filtering to power frequency fault component voltage and current, respective Aerial mode component is extracted；

(3) product of line mode voltage average and line mould electric current average is calculated；Using the positive and negative as the positive event of judgement of average product The foundation of barrier and reverse fault；Using the fault direction of all outlets differentiate result as judge bus whether failure foundation：

A：It is positive failure if the modulus average product code detected by certain the bus protection unit of outlet is negative；

B：If it is reverse fault just that the modulus average product code detected by certain the bus protection unit of outlet is；

C：It is bus-bar fault if each branch road bus protection unit being connected with bus is determined as reverse direction failure；

In the step (3), specific basis for estimation is：

1) with formula S_m=ave (Δ u_m(t))×ave(Δi_m(t)) it is positive and negative as identification fault direction criterion, formula In, ave (Δ u_m(t)) and ave (Δ i_m(t)) it is respectively the m articles fault component of outlet being connected with bus after phase-model transformation Line mode voltage and line mould electric current average, S_mIt is the line mode voltage and the average product of line mould electric current of the m articles outlet, if S_mFor just, Reverse fault is then determined as, if S_mIt is negative, then is determined as positive failure；

2) with formulaUsed as the foundation whether bus breaks down is judged, in formula, n is represented and mother The number of the connected outlet (including transformer branch and circuit) of line；In formula, sign (S_m) it is S_mSymbol, it is stipulated that work as S_m>When 0, sign(S_m)=1；Work as S_mWhen=0, sign (S_m)=0；Work as S_m<When 0, sign (S_m)=- 1.If λ is n, the bus is determined as Failure；Otherwise, bus is normal.

Recognition principle of the invention is：

1 accident analysis

The transmission line of electricity that either substation bus bar is still attached thereto breaks down, from superposition theory, any event Barrier all adds a voltage source equivalent in trouble point, and the voltage and current produced by the voltage source is fault component.Thus may be used Extract real-time fault component, so as to realize the identification of bus internal fault external fault.Fig. 1 show a simple substation bus bar structure Failure schematic diagram, the bus has 3 outlets, respectively l₁To l₃。R₁、R₂And R₃Be bus protection unit, respectively in bus B and l₁Upper setting failure, for every circuit, it is stipulated that the positive direction of failure is that bus points to circuit.

1) bus-bar fault.If f on Fig. 1 median generatrixs B₁There is three phase short circuit fault, its super-imposed networks such as Fig. 2 institutes in point Show.

In Fig. 2, it is assumed that each outlet is lossless circuit, L₁、L₂And L₃It is the inductance of each circuit and equivalent power supply.By circuit Theory understand, super-imposed networks be in whole network all electromotive force of source zero setting, only trouble point electromotive force independent role and The network of formation, the electromotive force is opposite with the voltage swing equal direction of the point before failure.If the voltage of failure prior fault point is V_F=U_mSin (ω t+ θ), then protect installation place R₁Fault component voltage Δ u₁(t) and fault component electric current Δ i₁(t) and its Value product S₁Calculating process it is as follows：

Δu₁(t)=- U_msin(ωt+θ) (2)

In formula, X₁=ω L₁, θ is fault initial angle, ave (Δ u₁(t)) and ave (Δ i₁(t)) it is respectively fault component electricity The average of pressure and fault component electric current, S₁For average is accumulated.Using formula (2), (4) and (7), when can obtain several typical fault initial angles Fault component voltage, electric current and its average product waveform, such as shown in Fig. 3 (a)-Fig. 3 (d), each electrical quantity is perunit in figure Value.

Fig. 3 (a)-Fig. 3 (d) shows, S₁It is just in special time after a failure.By calculating：At the beginning of failure Beginning 0≤θ of angle satisfaction<During π, 0<t<The S of T (π-θ)/in the π time periods₁For just；When fault initial angle meets π≤θ<During 2 π, 0<t <T (2 π-θ) S in the/π time periods₁For just, T here is a power frequency period, i.e. 20ms.

Knowable to same analysis, R₂And R₃The average product and R for detecting₁The average product for detecting has identical feature.Thus Understand, during bus-bar fault, in specified time interval, the fault component voltage that each outlet exit bus protection unit is detected All it is just with the average product code of fault component electric current.

2) outlet failure.If the circuit l in Fig. 1₁Upper f₁There is three phase short circuit fault, its super-imposed networks such as Fig. 4 institutes in point Show.In figure, L₁₁And L₁₂It is respectively trouble point to bus B and trouble point to the inductance of line end.

Similar bus-bar fault analysis, protection location R in Fig. 4₁The fault component voltage Δ u at place₁(t) and fault component electric current Δi₁T () and its average accumulate S₁Result of calculation is as follows：

In formula, L_2//3=L₂L₃/(L₂+L₃), X₁₁=ω L₁₁, X_2//3=ω L_2//3, X '=X₁₁+X_2//3.Using above formula, R can be obtained₁What fault component voltage and fault component electric current and its average during several typical fault initial angles that place detects were accumulated Shown in waveform, such as Fig. 5 (a)-Fig. 5 (d), each electrical quantity is perunit value in figure.

From Fig. 5 (a)-Fig. 5 (d), S₁It is negative in special time after a failure.Simultaneously by can be calculated：When 0≤ θ<During π, 0<t<The S of T (π-θ)/in the π times₁It is negative；As π≤θ<During 2 π, 0<t<T (2 π-θ) S in the/π times₁Also be it is negative, this Place T=0.02s.

Similar analysis understand：R₂And R₃There is identical feature when the average product of unit detection is with bus-bar fault, i.e., in failure S in special time afterwards₁For just.It follows that during any one outlet failure, in specific time interval, failure Fault component voltage and the average product of electric current on circuit are negative, and the average of non-fault line product is for just.

Bus protection does not need Fault Phase Selection, is the various fault types of reaction, can be using line mode voltage and line mould electric current Average is accumulated to extract fault signature.There is single mode amount in view of transformation matrixs such as existing Clarke can not react all failure classes The problem of type, a kind of new phase-model transformation is used for this, as shown in formula (11)：

In formula, f_a、f_bAnd f_cCan be fault component voltage or fault component electric current, the modulus for obtaining is converted by formula (11) f₁And f₂All fault types can be reflected.

The structure of 2 criterions

According to above-mentioned analysis, either outlet failure or bus-bar fault, within the specific time period, can obtain conclusion such as Under：

(1) when the forward direction of certain outlet breaks down, detected by the exit bus protection unit in this circuit Modulus average product code is negative, and during reverse fault, symbol is for just, this conclusion is adapted to any outlet.

(2) when being broken down on bus, detected in top (near bus bar side) bus protection unit of all circuits Modulus average product code be just.

For every outlet, the positive direction of failure definition points to this circuit, ave (Δ u for bus_m) and ave (Δ i_m) respectively It is the average of line mode voltage after the m articles outlet phase-model transformation and line mould electric current, it is as follows：

In formula, j is the sampling number for calculating, and N is every cycle sampling number.For convenience of identification fault direction, construction Criterion is as follows：

S_m=ave (Δ u_m)×ave(Δi_m) (14)

If S_mIt is negative, then is determined as the m articles outlet positive direction and breaks down；Otherwise, failure occurs in opposite direction.Total score The fault direction of all circuits that analysis is connected with bus, if failure is all direction, judges bus-bar fault.For there is n bar outlets Bus, construction bus criterion it is as follows：

In formula, sign (S_m) it is S_mSymbol, it is stipulated that work as S_m>When 0, sign (S_m)=1；Work as S_mWhen=0, sign (S_m)=0； Work as S_m<When 0, sign (S_m)=- 1.If λ is n, the bus-bar fault is determined as；Otherwise, bus is normal.

Simulation analysis are carried out with the analogue system of Fig. 1：

1) model is set up

According to the primary system structure and relevant parameter of the actual 500 kV transformer stations in somewhere, using PSCAD/EMTDC structures Bus simulation model is made, as shown in Figure 7.

Fig. 7 shows that I is female to be connected and II mothers between by 3 string switches, has 4 back into outlet, 2 times transformer branches.R_iIt is Decentralized bus protection unit, the exit loaded on each circuit.Wherein, R₁、R₃And R₅One group is constituted, CT is extracted respectively₁、CT₃With CT₅Electric current, be responsible for the female running statuses of identification I；R₂、R₄And R₆Another group is constituted, CT is extracted respectively₂、CT₄And CT₆Electric current, It is responsible for the female running statuses of identification II.C₁And C₂It is the stray capacitance over the ground of bus, takes 0.01 μ F.Transmission line of electricity uses frequency phase Close model, and uniform transposition, the length of each circuit as shown in Figure 7, for each bus protection unit, it is stipulated that the positive direction of failure It is that each circuit is pointed to by bus.High fdrequency component is filtered using low pass filter, is then calculated using Aerial mode component.Current intelligence The sample frequency of combining unit is generally 80 points/every cycle in energy transformer station, therefore sample frequency is set to 4 kHz, and the present invention is adopted With 10 data of continuous sampling point come Judging fault direction.

2) Adaptability Analysis of protection philosophy

Analyzed by single busbar, it is proposed that the bus protection principle based on modulus average product, the theory analysis protection is sentenced According to can effectively recognize whether single busbar breaks down.But for complicated bus structure, 500 kV mono- as shown in Figure 7 The half breaker bus mode of connection, the breaker between two buses is in the mother of closure state, i.e., two in normal operation Line is joined directly together.Now, carry whether protection philosophy still adapts to, theory analysis is as follows.

If breaking down the (f such as on I buses on bus₁Point), for each protection location of I mothers side, with single busbar feelings Condition is identical, R₁、R₃And R₅Differentiate that opposite direction breaks down, be comprehensively identified as I mother's troubles inside the sample spaces；List is respectively protected for II mothers side Unit, in theory analysis can be obtained, the R in specified time interval₂、R₄And R₆Modulus average product be negative, therefore it is former to be judged to forward direction Barrier.But because I is female and mother II is joined directly together and apart from close, may not all protection location be all judged to positive failure, but This does not influence the correct identification to failure, because only that when all reverse fault is judged to the connected all protection locations of bus, Just it is judged to bus troubles inside the sample space；Otherwise, then it is bus external area error.

If any bar line failure (such as circuit l₂On f₂Point), the R in specified time interval₁And R₂Average product is equal It is negative, i.e., respective positive direction breaks down, according to bus protection criterion, protection all differentiates that respective bus is normal.Other outlets are sent out Raw failure, is also such.

In sum, putting forward bus protection principle should be able to be applied to one-and-half breaker bus connection type in theory.

3) simulation and analysis of different faults primary condition

The performance of bus protection is easily influenceed by different faults primary condition, such as fault initial angle, fault ground electricity Resistance and fault type.In order to test influence of the different faults primary condition to proposed protection scheme, following emulation has been carried out.

The emulation testing of a, different faults initial angle.To investigate adaptability of the protection philosophy under different faults initial angle, F on I buses is set₁There is B phase earth faults in point, fault initial angle is respectively 0 °, 120 ° and 330 °, and simulation result is shown in Table 1.If Put circuit l₂Upper f₂There is C phase earth faults in point, fault initial angle and corresponding simulation result are shown in Table 2.

The emulation data of different faults initial angle during the I of table 1 mother's failures

The circuit l of table 2₂The emulation data of different faults initial angle during failure

The two tables emulation data more than, for the bus internal fault external fault of different initial angles, protection can correctly be done Go out to judge.During zero initial angle failure, average product decrease, but do not influence to bus whether the normal identification of failure, criterion tool There is sufficiently high reliability and sensitivity.

The emulation testing of b, different faults earth resistance.F on I buses is set₁There is AB earth faults, earth resistance point in point Not Wei 50 Ω, 150 Ω and 300 Ω, simulation result is shown in Table 3.Circuit l is set₂Upper f₂There is AC earth faults, earth resistance point in point Not Wei 0 Ω, 200 Ω and 300 Ω, simulation result is shown in Table 4.

The emulation data of different faults resistance during the I of table 3 mother's failures

The circuit l of table 4₂The emulation data of different faults resistance during failure

Data are emulated from table 3 and table 4：No matter bus internal fault or external fault, with the increasing of fault resstance Greatly, the absolute value of the average product that each protection location is calculated reduces, but criterion identification fault direction is had little to no effect, two The protection location of bar bus can correctly recognize failure.

The emulation testing of c, different faults type.Respectively on II buses and circuit l₃The upper event that different faults type is set Barrier, simulation result is shown in Table 5 and table 6 respectively.

The emulation data of different faults type during the II of table 5 mother's failures

The circuit l of table 6₃The emulation data of different faults type during failure

When there is different type failure inside and outside the two table simulation results more than, bus area, protection can be made correct Judge.

4) emulation testing of string added time is considered.For longer-distance supertension line, sometimes through installing serial compensation capacitance To improve transmission capacity, so influence of the serial compensation capacitance to protecting need to be considered.In l₁It is upper that series capacitance, string are installed at I mothers Benefit degree is set to 40%.Respectively in f₂、f₄And f₅(l₁At 80 km of I mothers) failure is set, simulation result is shown in Table 7.

Simulation result after table 7 plus string benefit

The data of table 7 contrast and can obtained with the data for being not added with the string added time, plus average product changes less after string benefit, protection Correctly can reliably recognize failure.

5) CT saturations impact analysis

Traditional bus protection is susceptible to malfunction in external area error CT saturations.In order to probe into CT saturations to conventional busbars The influence of differential protection and institute's extracting method, in l₃Upper setting B phase earth faults, and CT₃B phases there is saturation, then I is female and II is female The B phase currents of each outlet are as shown such as Fig. 8 (a)-Fig. 8 (c) and Fig. 9 (a)-Fig. 9 (c) respectively, each difference that corresponding I is female and II is female Shown in streaming current such as Figure 10 (a)-Figure 10 (c) and Figure 11 (a)-Figure 11 (c).Figure 12 (a), Figure 12 (b) and 13 (a), Figure 13 (b) are The fault component line mode voltage of institute's extracting method and the waveform of fault component line mould electric current, corresponding emulation data are as shown in table 8.

The simulation result of the CT saturations of table 8

From Fig. 8 (a)-(c), 9 (a)-(c), 10 (a)-(c) and Figure 11 (a)-(c) as can be seen that the B phase currents of circuit 3 exist 4.95ms has reached saturation after failure, and the difference current of I mother's B phases also increases to 4659A from 0, therefore I female differential protection can be by mistake It is dynamic.Figure 12 (a), Figure 12 (b) and Figure 13 (a), Figure 13 (b) and table 8 show that carried Protection criteria can correctly judge in CT saturations It is bus external area error, because the method was protected before CT saturations and just made only using the data window of 2.5ms after failure Judge.

The present invention first carries out phase-model transformation to fault component, recycles the product of the average of line mode voltage and line mould electric current to enter Row Fault Identification, and whether the invention broken down on bus for is recognized.The invention does not need Fault Phase Selection and utilizes work Frequency fault component is calculated, and sample frequency as little as 4kHz, traditional CT and CVT Transfer characteristics can meet requirement.In addition, should The data window that invention only needs to 2.5ms is calculated, and amount of calculation is small, quick action.

Although above-mentioned be described with reference to accompanying drawing to specific embodiment of the invention, not to present invention protection model The limitation enclosed, one of ordinary skill in the art should be understood that on the basis of technical scheme those skilled in the art are not Need the various modifications made by paying creative work or deformation still within protection scope of the present invention.

Claims (7)

1. it is a kind of based on fault component average product quick bus bar protecting method, it is characterized in that：Comprise the following steps：

(1) voltage and current at each outlet bus protection element that Real-time Collection is connected with bus；

(2) after the voltage and current filtering that will be gathered, phase-model transformation is carried out to power frequency fault component voltage and current, extracts failure The Aerial mode component of component voltage and electric current；

(3) calculate the product of line mode voltage average and line mould electric current average, in special time period, using average product it is positive and negative as Judge the foundation of positive failure and reverse fault, then differentiate whether result is former as bus is judged using the fault direction of all outlets The foundation of barrier, specific differentiation includes：If the modulus average product code detected by certain the bus protection unit of outlet is negative, It is positive failure；If it is reverse fault just that the modulus average product code detected by certain the bus protection unit of outlet is； It is bus-bar fault if each branch road bus protection unit being connected with bus is determined as reverse direction failure.

2. a kind of quick bus bar protecting method based on fault component average product as claimed in claim 1, it is characterized in that：It is described In step (2), the concrete mode of phase-model transformation is：

$\left(\begin{array}{c}{f}_0\\ f_1\\ f_2\end{array}\right)=\left(\begin{array}{ccc}1& 1& 1\\ 1& 2& -3\\ 1& -3& 2\end{array}\right)\left(\begin{array}{c}{f}_a\\ f_b\\ f_c\end{array}\right)---\left(16\right)$

In formula, f_a、f_bAnd f_cIt is fault component voltage or fault component electric current, the 1 mold component f that conversion is obtained₁With 2 mold component f₂ Can all fault types of reflection, f₀It is 0 mold component.

3. a kind of quick bus bar protecting method based on fault component average product as claimed in claim 1, it is characterized in that：It is described In step (2), the full voltage and total current that will be collected first are filtered after load component filters high fdrequency component again and obtain power frequency failure Component.

4. a kind of quick bus bar protecting method based on fault component average product as claimed in claim 1, it is characterized in that：It is described In step (3), specific basis for estimation is：With the line mode voltage average of certain outlet and the product S of line mould electric current average_m= ave(Δu_m(t))×ave(Δi_m(t)) it is positive and negative as identification fault direction criterion, in formula, ave (Δ u_m(t)) and ave (Δi_m(t)) it is respectively that the m articles fault component of outlet being connected with bus is electric through the line mode voltage after phase-model transformation and line mould The average of stream, S_mIt is the line mode voltage and the average product of line mould electric current of the m articles outlet, if S_mJust, to be then determined as reverse fault, If S_mIt is negative, then is determined as positive failure.

5. a kind of quick bus bar protecting method based on fault component average product as claimed in claim 1, it is characterized in that：It is described In step (3), calculateIn formula, sign (S_m) it is S_mSymbol, S_mFor the m articles line mode voltage of outlet and The average product of line mould electric current, it is stipulated that work as S_m>When 0, sign (S_m)=1；Work as S_mWhen=0, sign (S_m)=0；Work as S_m<When 0, sign (S_m)=- 1, if formulaSet up, be then determined as bus-bar fault；Otherwise, bus is normal, and n is represented and mother The total number of the connected outlet of line.

6. a kind of quick bus bar protecting method based on fault component average product as claimed in claim 5, it is characterized in that：With mother The connected outlet of line includes transformer branch and circuit.

7. a kind of quick bus bar protecting method based on fault component average product as claimed in claim 1, it is characterized in that：It is described In step (3), failure positive direction is that bus points to outlet.