CN100546143C - A kind of low current grounding detects the device and method with the location - Google Patents

Abstract

A kind of low current grounding detects the device and method with the location, and this device comprises slave computer and the host computer of being made up of CPU module, DSP, preposition circuit units module, A/D modular converter, memory module, Display And Keyboard operational module, communication module; Wherein preposition return circuit module, the A/D modular converter, the CPU module, DSP connects successively, memory module, Display And Keyboard operating unit module, communication module links to each other with the CPU module respectively, host computer links to each other with communication module, the analog signal of the residual voltage of CPU module collection bus and the zero-sequence current of each circuit, regulate its size in proportion and make it to become the treatable amplitude range of device, be converted into the digital signal that computing module can be discerned, by the DSP analytic signal, judge whether to break down, provide the route selection result if break down, preserve fault message, and send the route selection result to host computer and carry out fault alarm.

Description

A kind of low current grounding detects the device and method with the location

Technical field

The invention belongs to the power transmission and transformation technical field, particularly a kind of low current grounding detects the device and method with the location.

Background technology

66kV and 35kV electrical network mainly adopt the neutral by arc extinction coil grounding mode in China's power distribution network, and 3kV ~ 10kV electrical network is then in the isolated neutral mode, and the low resistance grounding mode is adopted in indivedual areas as above part urban distribution networks such as sea and Beijing, Guangzhou.During this system's generation single phase ground fault (generally accounting for more than 70%), because the electric current of fault point is very little, reasons such as electric arc instability, the earthing wire-selecting problem all is not well solved always.Domestic five kinds of popular selection methods have power direction method, harmonic analysis method (being that colony is than width of cloth phase comparing method) quintuple harmonics method, signal injection method and wavelet method at present.

(1) power direction method: bigger and direction is opposite according to the real component of faulty line than the real component of non-fault line, judge that the power direction of every circuit zero-sequence current is determined faulty line.But, real component is also very little in the fault current, is subject to the influence of factor such as unsymmetrical current in the zero-sequence current filter, and this method does not reach 100% accuracy rate in principle, a line-to-ground be may occur, many line-to-grounds or a result who all can not judge but judged.

(2) harmonic analysis method: the colony of zero sequence steady-state signal is than width of cloth phase comparing method behind the harmonic analysis method employing single-phase earthing, because than amplitude ratio phase time, what adopt is principle of relativity, in isolated neutral system, the effect of this method is better, but in arc suppression coil earthing system because the compensating action of arc suppression coil, the route selection rule can lose efficacy, and the zero-sequence current that causes for the CT imbalance, this method can not effectively solve.

(3) quintuple harmonics method: in arc suppression coil earthing system,, still can be similar to the electric current sum that the size of current of regarding faulty line as equals all non-fault lines, the current opposite in direction of direction and non-fault line for the quintuple harmonics component.The quintuple harmonics method has solved the failure line selection problem of neutral point through the arc suppression coil system, its deficiency be that quintuple harmonics content only accounts for first-harmonic in the fault electric current about 1/10, numerical value will be littler under the situation that transition resistance ground connection is arranged, and easily causes erroneous judgement.

(4) signal injection method: though wiring is simple, do not need zero sequence CT loop, owing to inject the system that the restriction of signal magnitude and method generally is mainly used in 10KV and following electric pressure.In addition, the sensitivity of probe and reliability are subject to the influence of various extraneous factors, and to some inconvenience of use of complex automatic system and unattended transformer station.

(5) wavelet method: its theoretical foundation is to approach peaked moment owing to the breakdown earth fault that causes of insulation in the electrical network often occurs in phase voltage, therefore, transient state capacity current after the fault can be regarded as owing to the fault phase voltage reduces suddenly the discharge capacity electric current that causes and because the charging capacitor current both sum that the rising suddenly of non-fault phase voltage causes, transient current then is other each line current sum in the faulty line, on change direction, the non-fault line transient current is opposite with the variation of faulty line transient current.Just can be used as the standard that faulty line is judged according to these 2.The shortcoming of wavelet method is that the transient process duration is shorter, and can't reappear, and just decays to very little value after next cycle of ordinary circumstance, therefore must can catch transient information and makes accurate judgment.

Because the distribution net work structure complexity, single phase ground fault has diversity again, and available fault current is very little usually, and relative signal-to-noise ratio is very low, adds the restriction of measurement links precision, and therefore existing line selection apparatus can not satisfy actual needs well.On the whole, the low current fault situation is with big current failure situation difference.Big short circuit current situation feature is obvious, and value is very big, and malfunction and normal condition boundary are clearly demarcated; The small current neutral grounding situation is then different, and the fault amount is very little, malfunction and normal condition boundary fuzzy, and feature is not obvious, and the scope of malfunction is very big, and earth resistance may be very big, also may be very little.In addition, we think that also there is following problem in domestic Small Electric Current Earthing And Routing Device: caused the operational reliability of device very low as existing serious inadequate natural endowment on the hardware circuit design; The on-the-spot wiring problem of installing; Its route selection difficulty of system of band arc suppression coil is bigger, easily erroneous judgement; Currently marketed this series products is very different etc.

Comprehensive above the analysis as can be known at present domesticly still is in conceptual phase in this field, and for the also generally acknowledged effective product of little electric current route selection and positioner, but electric power enterprise is but very urgent for the demand of this function.

Summary of the invention

At prior art, the invention provides a kind of fault detect and positioner and method of small current neutral grounding.This Device Testing method also adopts harmonic analysis method, energy method etc. except adopting the selection method of using wavelet transformation extraction fault transient information; And determine method in conjunction with the fault detection method of fuzzy self-adaption reasoning and based on the active domain of rough set theory.(DSP is the abbreviation of digital signal processor among the present invention, and ARM is the abbreviation of ARM microprocessor.) the present invention is national high-tech research development plan (" 863 " plan) problem achievement.

The task that low-current ground fault line selection device need be finished is successively: the analog signal of the residual voltage of CPU module collection bus and the zero-sequence current of each circuit, regulate its size by proper proportion and make it to become the treatable amplitude range of device, be converted into the digital signal that computing module can be discerned, DSP judges whether to break down according to certain algorithm principle analytic signal.If break down and provide the route selection result, preserve fault message, and send the route selection result to host computer and carry out fault alarm.

Hardware unit of the present invention comprises slave computer and the host computer of being made up of CPU module, DSP, preposition return circuit module, A/D modular converter, memory module, Display And Keyboard operational module, communication module; Wherein preposition return circuit module, A/D modular converter, CPU module, DSP connect successively, and memory module, Display And Keyboard operating unit module, communication module link to each other with the CPU module respectively, and host computer links to each other with communication module.

Described CPU module adopts embedded-type ARM microprocessor U1, the HD0 of U1, HD1, HD2, HD3, HD4, HD5, HD6, HD7 link to each other with D0, D1, D2, D3, D4, D5, D6, the D7 of DSP digital signal processor U2 respectively, and the HCNTL1 of U1, HCNTL0, HBIL, HR/W, nWE, nOE, nGCS1 link to each other with A3, A2, A1, A4, HDS2, HDS1, the HCS of U2 respectively.The VCLK of U2, VD0, VD1, VD2, VD3, VD4, VD5, VD6, VD7, GPC15, VFRAME, VLINE link to each other with CP, VK0, VK1, VK2, VK3, VK4, VK5, VK6, VK7, DISP, FRM, the LOAD of LCD display interface chip U4 in keyboard and the display module respectively; The chip U7 that resets links to each other with the nRest pin of U2 by pin RST; D0～D15 of A/D modular converter U3 links to each other with D0～D15 of U1 by the D0 of latch U5, and the BUSY of U3 links to each other with the IO2 of U1, and the output end vo ut of power supply chip U6 provides 1.8V power supply.

The function of described preposition return circuit module is the collection of simulant signal of zero-sequence current amount, residual voltage amount.J1, J3 link to each other with the voltage transformer of the current transformer of gathering the zero-sequence current amount, collection residual voltage amount respectively, and J2 links to each other with the A/D modular converter, and J4 links to each other with the input of counter, and the output of counter links to each other with ARM.Between interface J1 and the interface J2 RC filter circuit is arranged, between interface J3 and the interface J4 photoelectrical coupler filtering is arranged.Wherein the pin 1,2,3,4,5,6,7,8,10,11,12,13 of J1 links to each other respectively at the pin 1,2,3,4,5,6,7,8,10,11,12,13 of J2, the pin 1,2,3,4,5,6 of J3 is by being linked to each other with the pin 2 of six photoelectrical couplers, six diode cathodes respectively by the series circuit of two resistance, each diode cathode, negative pole link to each other with the pin 2,1 of corresponding photoelectrical coupler respectively, the pin 5 of six photoelectrical couplers links to each other with the input of six reversers, and the output of six reversers links to each other respectively at 1,2,3,4,5,6 pins of J4.J4 links to each other with the input of counter.

The data port of described A/D modular converter directly links to each other with the data port of ARM.

Described memory module is not corresponding a certain chip or certain circuit module, but inner each storage area of single-chip microcomputer is comprehensive, why they are classified as a module, mainly be because they comprehensively finished 32 SDRAM accumulator systems of memory function of single-chip microcomputer, employing be the circuit that two chips of HY57V56162OCT compose in parallel.A0～A11 of U8, U9, BA0, BA1 link to each other with ADD0～ADD13 of U1 respectively, DQ0～DQ15 of U8, U9 links to each other with XDATA0～XDATA31 of U1 successively, the CS of U8, U9, RAS, CAS, WE, SCLK, SCKE link to each other with nSDCS (0), nSDRAS, nSDCAS, nDWE, SDCLK, the CKE of U1 respectively, and the LDQM of the LDQM of U8, UDQM, U9, UDQM link to each other with nWBE0～nWBE3 successively.

Small Electric Current Earthing And Routing Device needs some man-machine conversational operations in the described Display And Keyboard operational module, be provided with, the running status of device is monitored etc. such as the parameter that needs the people to device, the content of this part is finished by button is set in the hardware designs.The Display And Keyboard operational module links to each other with U1 by memory module.

Described communication module is considered the needs at unattended operation and comprehensive automation station, so increased the function that communicates contact with upper level department.Serial port itself only provides hardware configuration and basic communication work mode to mutual channel.The design of communication with this device and upper level department in actual design becomes two kinds, and the actuating signal of device is uploaded by serial mode or relay tip mode.The computer serial line interface adopts the RS232 agreement.The pin 1,2 of U8 links to each other with 2,3 pins of 232 sockets, and 232 sockets link to each other with the host computer serial ports by 232 cables.

Handling little current single-phase grounding problem only only can not all make accurate judgment to various single-phase earthing situations with a kind of fault signature amount in other words with a kind of selection method, the various feature performances that should excavate and utilize single phase ground fault to cause as much as possible, the research effective ways extract and discern these features, form the Intelligent Composite wire selection system, just may reach accurate route selection purpose.Here so-called Intelligent Composite wire selection system is that multiple selection method is combined, and cooperation layer in a organized way on selection method is selected distinct methods at the different faults situation, and system has flexibility, opening and intelligent.In the present invention, except adopting the selection method of using wavelet transformation extraction fault transient information, also adopt harmonic analysis method, quintuple harmonics analytic approach, power direction method.And determine method in conjunction with the fault detection method of fuzzy self-adaption reasoning and based on the active domain of rough set theory.By above mode, avoided the deficiency of single selection method effectively, stable state information and transient information when well having utilized system's single-phase earthing, thus make the route selection result that obtains more accurate and approaching actual.

Fault detect of the present invention and localization method may further comprise the steps:

Step 1, beginning;

The neutral point voltage value is gathered in step 2, enforcement;

Step 3, judge whether out-of-limitly, if not, change step 2, if, execution in step 4;

Step 4, be decided to be that device starts and start and exchange transmitter;

Step 5, signal adjustment;

Step 6, gather each circuit zero-sequence current, residual voltage and each line current, voltage, power signal;

Step 7, call faulty line and judge sub-process;

Step 8, call fault distance and judge sub-process;

Step 9, packing data are handled;

Step 10, judgement and host computer network break-make, if logical, execution in step 11; If obstructed, execution in step 12;

Step 11, data are sent to host computer display alarm, execution in step 13;

Step 12, storage are at local hard drive;

Step 13, end.

Faulty line is judged what sub-process was carried out according to the following steps:

Step 1, beginning;

Step 2, receive data and put into internal memory;

Step 3, use power direction route selection flow process respectively, harmonic analysis route selection flow process, quintuple harmonics route selection flow process, small echo route selection flow process is carried out route selection;

Step 4, according to the consequence devised decision table;

Step 5, definite based on the route selection active domain of rough set theory;

According to the multiple selection method that proposes, the present invention proposes using rough collection theory the fault sample collection is carried out data mining and Knowledge Discovery, determines the active domain of various selection methods.This method is main tool with the decision table, the fault sample data is carried out discretization handle, and redundant information is carried out Reduction of Knowledge, finally obtains the decision rule between fault-signal feature and selection method; Expression-form by probability is effectively handled inharmonious decision rule.

Determine that based on the route selection active domain of rough set theory method carries out according to the following steps:

Step 5.1, fault data discretization;

Step 5.2, yojan;

Coefficient is selected in step 5.3, calculating;

For the comprehensive selection of each criterion of distribution circuit single-phase earth fault, we will differentiate weight

$\mathrm{\λ}=\underset{j=1}{\overset{r\left(d\right)}{\mathrm{\Σ}}}{s}_j\·\frac{c_j}{r_j}---\left(1\right)$

As criterion.Wherein $c_j=\frac{l_{j.\min }}{l_j}$ Be sensitivity coefficient, i.e. the minimum possible range of this line fault, l _jBe the distance of fault point to harvester; $r_j=\frac{l_{j+1.\max }-l_j}{l_j}$ For selecting coefficient, i.e. the maximum possible scope of line fault; $s_j=\frac{\mathrm{Card}(X\∩Y)}{\mathrm{Card}\left(U\right)}$ Be the support weights of criterion, wherein X is the prerequisite attribute, and Y is the conclusion attribute, and U is a domain; R (d) is the number of decision attribute, and all the other symbols will provide concrete meaning in the following description.

Step 5.4, set up the validity fuzzy model of every kind of flow process;

When applied voltage and the magnitude of current carried out failure diagnosis, the fault current when we consider circuit generation single-phase short circuit can be expressed as $I_{f.j}=\frac{E_s}{X_s+X_j{l}_j}---\left(2\right)$

E wherein _sEquivalence calculating phase electromotive force for system; X _sBe equivalent reactance under system's normal operating mode; X _jPositive sequence reactance for circuit unit's kilometer length; l _jBe the distance of fault point to harvester.At this moment, Dui Ying system line voltage is $U_{f.j}=\sqrt{3}{I}_{f.j}{X}_j{l}_j---\left(3\right)$

Below we are that example is carried out qualitative, quantitative analysis with the electric current.When single-phase earthing fault occurs in corresponding circuit longest distance and system and operates in maximum operational mode, have $l_{j.\max }=\frac{1}{X_j}(\frac{E_s}{I_{f.j}}-X_{\min })---\left(4\right)$

Our assumed fault is put road along the line and is evenly distributed, and is 1 when satisfying the circuit sensitivity coefficient, i.e. l _J.min=l _j, differentiate some this moment and be taken as system's current value during line end generation single-phase short circuit under minimum operational mode, then when having during single-phase short circuit under next section circuit generation maximum operational mode

I _j+1.max＝I _f.j (5)

Promptly $\frac{\sqrt{3}}{2}\frac{E_s}{X_{\max }+X_j{l}_j}=\frac{E_s}{X_{\min }+X_j{l}_{j+1.\max }}---\left(6\right)$

Can solve $l_{j+1.\max }=\frac{2\sqrt{3}}{3}(\frac{X_{\max }}{X_j}+l_j)-\frac{X_{\min }}{X_j}---\left(7\right)$

At this moment, select coefficient to be $r_j=\frac{l_{j+1.\max }-l_j}{l_j}=\frac{\frac{2\sqrt{3}}{3}(\frac{X_{\max }}{X_j}+l_j)-\frac{X_{\min }}{X_j}-l_j}{l_j}---\left(8\right)$

In like manner, to select coefficient be 0 when the differentiation point of electric current satisfies circuit, i.e. l _J.max=l _j, differentiate some this moment and be taken as system's current value during line end generation single-phase short circuit under maximum operational mode, then when I is arranged during short circuit under this section circuit generation minimum operational mode _J.min=I _F.j(9)

Promptly $\frac{\sqrt{3}}{2}\frac{E_s}{X_{\max }+X_j{l}_{j.\min }}=\frac{E_s}{X_{\min }+X_j{l}_j}---\left(10\right)$

Can solve $l_{j.\min }=\frac{\sqrt{3}}{2}(\frac{X_{\min }}{X_j}+l_j)-\frac{X_{\max }}{X_j}---\left(11\right)$

This moment, sensitivity coefficient was $c_j=\frac{l_{j.\min }}{l_j}=\frac{\frac{\sqrt{3}}{2}(\frac{X_{\min }}{X_j}+l_j)-\frac{X_{\max }}{X_j}}{l_j}---\left(12\right)$

When we study this circuit as the benchmark circuit, can be similar to and think X _Min≈ X _Max≈ X _jl _j, then can solve r _j≈ 0.3, c _j≈ 0.7, promptly when sensitivity coefficient is 1, selects coefficient to be about 0.3, and when selecting coefficient to be 0, sensitivity coefficient is about 0.7.By above analysis as can be known, sensitivity coefficient should be (0.7,1), and selects coefficient to should be (0,0.3).In like manner, we can also analyze for voltage properties, can lead to the same conclusion.

The malfunction monitoring of step 6, fuzzy self-adaption reasoning;

In order to carry out fuzzy decision, detected single phase ground fault data must be converted to the fuzzy membership value that can carry out quantitative analysis through obfuscation.Fuzzy membership function can have multiple choices, such as trigonometric function, Gaussian function and exponential function etc.By measured data utilization learning algorithm and Analysis on Mechanism to the scene operation, can extract one group of fuzzy decision rule, the fuzzy decision that is extracted rule forms a decision rule storehouse.Normally, the text description form of i bar fuzzy decision rule Ri is as follows:

The Ri:If running status belongs to the i bar subclass in decision condition space,

The result of decision of the current circuit operation conditions of then is ...

In the decision-making precondition, constitute decision condition space (decisioncondition space) C, C={c by the running status of m variable description ₁, c ₂..., c _j..., c _m, c wherein _jThe running status of representing j class distribution line operational factor to represent.In decision conclusions, all alternative n The reasoning results constitute result of decision space (, single-phase earthing normal as moving and system resonance etc.) D, D={d ₁, d ₂..., d _i..., d _n, d wherein _iRepresent the i class result of decision.The running status that each class distribution line operational factor is represented can be divided into v degree fuzzy subset, and the degree of membership that current running status belongs to each fuzzy subset is E={e ₀, e ₁..., e _k..., e _V-1, e wherein _kThe running status of representing this distribution line operational factor to represent departs from the degree of its normal value.Each class result of decision can be divided into u degree fuzzy subset equally, and the degree of membership that each class result of decision belongs to each fuzzy subset of its correspondence is F={f ₀, f ₁..., f _k..., f _U-1, f wherein _kThe degree of representing such result of decision possibility.

Adopt above-mentioned fuzzy self-adaption reasoning localization method can adapt to various working conditions change, can accurately judge the current operation conditions of distribution line, accuracy rate is very high; And can judge the distribution line of single phase ground fault within a short period of time and carry out concrete fault location, relative error satisfies on-the-spot actual needs fully less than 1.5% of the distribution line total length.

The core of Intelligent Composite wire selection system is the design of organizing and coordinating layer.Texture's cooperation layer need be finished the work of two aspects: the one, need to determine the validity zone of the whole bag of tricks, and this need of work is according to a large amount of actual sample, determines in conjunction with Theoretical Calculation necessarily; The 2nd, realize comprehensive arbitration functions, draw a final route selection result.

In fact comprehensive judgement is exactly an integrated decision-making process.Every kind of method is all exported a result, and provides average information to embody this result's confidence level.And decision-making level need take all factors into consideration these information, make final decision, if the validity area boundary of method is very clearly demarcated, decision system just is easy to make a policy so, but it is too harsh to do the requirement that certainly will cause method validity like this, the effective coverage is too little, and a lot of faults possibly can't be judged.The true colours of effective coverage are actually fuzzy, the border that neither one is clear and definite.So we also should follow this natural situation, handle with fuzzy method.The development of fuzzy mathematics provides important instrument for we solve fuzzy problem.

The fault monitoring method of fuzzy self-adaption reasoning is carried out according to the following steps:

Step 6.1, determine fuzzy Decision Making Method;

Step 6.2, average information obfuscation;

Step 6.3, fuzzy decision;

Step 6.4, the result is outputed to display unit;

Step 7, route selection finish.

Harmonic analysis route selection flow process is carried out according to the following steps:

Step 1, beginning;

Electric current, the voltage signal of 3 circuits of step 2, extraction electric current maximum;

The initial aggregate-value of initial aggregate-value s1, s2, s3 and the bus current s of step 3, the maximum three-line of setting electric current;

Step 4, electric current array, the pointwise of voltage array are compared;

Step 5, the identical s of the symbol absolute value that directly adds up; Absolute value on the contrary adds up; The full same settings s of symbol is a higher value;

Step 6, value are maximum is judged to be faulty line.

Quintuple harmonics route selection flow process is carried out according to the following steps:

Step 1, beginning;

Step 2, the amplitude of getting the quintuple harmonics current component;

Step 3, find out the circuit that the harmonic current components electric current has the increment amplitude;

The amplitude F of the quintuple harmonics component of the maximum of step 4, bay-line is as criterion;

Step 5, determine every corresponding F value of circuit with the hypothesis inspection technique;

Step 6, F value are faulty line to the maximum;

Step 7, end.

Power direction route selection flow process realizes according to the following steps:

Step 1, beginning;

Step 2, extract the zero sequence real component size and the phase place thereof of each circuit;

Step 3, judge that direction flows to and whether flow to bus and size equals All other routes real component and arc suppression coil zero sequence real component sum; If, execution in step seven; If not, execution in step four;

Step 4, judge that direction flows to circuit by bus and all circuit zero sequence real components all equal active loss current value own; If, execution in step five; If not, execution in step six;

Step 5, judgement bus are faulty line, execution in step seven;

Step 6, route selection failure;

Step 7, end.

Wavelet method route selection flow process is carried out according to the following steps:

Step 1, beginning;

Step 2, reception are uploaded data and are put into internal memory;

Step 3, to zero-sequence current In _iCarry out the small echo variation and obtain wavelet coefficient C _i

Step 4, judge whether polarity is identical; If, execution in step 10; If not, execution in step 5;

Step 5, get C _iThe circuit L of coefficient maximum _kAnd judge its polarity;

Step 6, judge whether the polarity of this circuit is opposite with other circuit; If, execution in step 7; If not, execution in step 11;

Step 7, this circuit are faulty line and note route selection sign L _k

Step 8, fault data warehouse-in also show;

Step 9, route selection finish.

Step 10, busbar grounding fault are returned step 8;

Step 9 is returned in step 11, route selection failure;

After the failure line selection sub-process finishes, if the route selection success then continues the corresponding current value of faulty line to be retained in the internal memory, and other non-fault line, promptly perfect the current value data of circuit and from internal memory, delete, then the data that keep are carried out wavelet analysis.Fault distance judgement sub-process can be undertaken by following step:

Step 1: fault distance judges that sub-process begins;

Step 2: according to route selection sign L _kThe current value I that keeps its corresponding line _kAnd delete other circuit and preserve current value in advance;

Step 3; In conjunction with fuzzy hyperbolic tangent model to I _kCarry out wavelet transformation and get each scale coefficient C _k

Step 4: to each coefficient C _kDelivery maximum;

Step 5: write down the 1st modulus maximum t constantly takes place ₁And write down its polarity;

Step 6: write down i modulus maximum polarity;

Step 7: judge whether polarity is identical, inequalityly then judge next modulus maximum, get back to step 6, identically then continue;

Step 8: find and the 1st the modulus maximum j that polarity is identical;

Step 9: judge whether to find, it takes place constantly to change step 10 to find record, does not find then range finding failure, changes step 13;

Step 10: write down it t constantly takes place ₂

Step 11: calculate fault distance x;

Step 12: result data warehouse-in/demonstration;

Step 13: finish.

The work that above-mentioned steps is finished is that the capable ripple of fault current is implemented wavelet transformation.Investigate the situation of change of wavelet transformation modulus maximum under different scale, to eliminate noise jamming.The polarity of the wavelet transformation modulus maximum that the wavelet transformation maximum that the reflected wave of fault point (comprising initial row ripple and the reflected wave that comes from the fault point) is produced and other two kinds of reflected waves (opposite end bus reflected wave, adjacent bus reflected wave) are produced is opposite, in view of the above, can effectively distinguish fault point row ripple and other row ripple, so just rejected other reflected wave, only the reflected wave of fault point has been analyzed.By threshold is set, remove the modulus maximum that other non-fault point reflected wave is produced, as the modulus maximum that exchange point produces, threshold can be used floating threshold, promptly is taken as to 10% of initial row ripple wavelet transformation modulus maximum under the dimensioning.Pairing yardstick is for detecting yardstick when selecting the capable ripple wavelet transformation of initial current modulus maximum maximum.Need to prove that for desirable step signal, because its modulus maximum is with dimensional variation, but selecting scale 2,3 is for detecting yardstick; Actual travelling wave signal, no matter how sharp-pointed its variation is, its modulus maximum under wavelet transformation increases this fact with the increase of yardstick and all exists, and just varies in size.According to the result, distribute as the foundation of detection with the wavelet transformation modulus maximum under this yardstick, by the determining positions of first modulus maximum and second modulus maximum distance that is out of order.

When finding range according to above-mentioned steps, noise signal, by the reflected wave of the reflected wave of the capable wave reflection component that exchange point produced, adjacent bus and opposite end bus all with disallowable (be not elimination truly, but we turn a blind eye to), finally be retained in the modulus maximum distribution in the current traveling wave, the traveling-wave component that just has only two kinds of character, be initial row ripple and the reflected wave that comes from the fault point, the two polarity is identical, and the range finding formula is:

x＝vΔt/2(13)

In the formula: v is a row wave speed, and Δ t is the time interval.

We see that clearly the traveling wave method range finding that utilizes wavelet transformation has realized our the set goal by simulation analysis, reached desirable range finding effect, but when realizing the short dot location, must catch transient current, the character pair point of voltage waveform signal sequence---zero sequence ripple flex point that sampling obtains exactly.And because the inevitable electromagnetic interference of industry spot, the zero sequence wave train that collects has been added much noise, and the characteristic point that how extracts signal in the middle of the noise exactly is the key of location.This project adopts the self adaptation change yardstick wavelet transformation that combines fuzzy hyperbolic tangent model to carry out the identification of zero sequence ripple flex point, not only can do effective filtering to primary signal, and main is the characteristic point that can accurately extract signal---zero sequence ripple flex point.

For the correct wavelet transform dimension a that selects, the present invention proposes a kind of new fringe spatial model, i.e. fuzzy hyperbolic tangent model, its state matrix is the hyperbolic tangent function of state variable, input matrix is linear permanent matrix.Fuzzy hyperbolic tangent model mainly has several big characteristics: this model is the essentially nonlinear model; Model is easy to be obtained by several fuzzy rules; This model is a kind of world model; Do not need to carry out the identification of fuzzy model structure, amount of calculation greatly reduces.

The rule of fuzzy hyperbolic tangent model can be expressed as:

R ⁱ：If?x ₁?is

x ₂?is

…，x _m?is

then $y^i=\±c_{x_1}\±c_{x_2}\±...\±c_{x_n}.$ Wherein, R ⁱRepresent i bar fuzzy rule, n is a number of fuzzy rules altogether,

(j=1,2 ..., m) be fuzzy set, just comprising (P) and negative (N) two language values.

(j=1 ..., m) be with

Corresponding positive constant.The symbol of its front is determined as follows: when

During for just (P),

The symbol of front is a positive sign; When

During for negative (N),

The symbol of front is a negative sign.x _iMembership function be taken as ${\mathrm{\μ}}_{P_{x_i}}\left(x\right)=e^{-\frac{1}{2}{(x-k_{\mathrm{xi}})}^2}---\left(14\right)$

${\mathrm{\μ}}_{N_{\mathrm{xi}}}\left(x\right)=e^{-\frac{1}{2}{(x+k_{\mathrm{xi}})}^2}---\left(15\right)$

K wherein _XiFor greater than zero constant.

When adopting the single-point obfuscation, sharpening adopts weighted mean method, when operation of direct product adopts the method for quadrature, then can draw following form of mathematical model according to this regular base:

y＝Atanh(k _xx)(16)

Wherein $A=\mathrm{diag}(C_{x_1},...,C_{x_m}),$ $k_x=\mathrm{diag}(k_{x_1},...,k_{x_m}).$

This model has utilized the composition and the inference mode of fuzzy rule cleverly, with the tanh model representation of an integral body one group of fuzzy rule.The regular simple structure of this model is easy to utilize people's experience.The final overall model that forms is easy to practical application.

Fuzzy hyperbolic tangent model rule base: n input variable of known MISO system is x=[x ₁(t) ..., x _n(t)] ^T, be output as y.Meet the following conditions if be used for describing the fuzzy rule base of this system, claim that then this group fuzzy rule base is a broad sense hyperbolic tangential type fuzzy rule base.

(1) wherein the form of the 1st fuzzy rule is

Rl：If(x ₁-d ₁₁)is

and(x ₁-d ₁₂)is

and…and

is

and(x ₂-d ₂₁)is

and(x ₂-d ₂₂)is

and…and

is

and...and(x _n-d _n1)is

and(x _n-d _n2)is

and…and

is

then $y^i={\mathrm{<figure-callout\; id="11"\; label="c\; F"\; filenames="C20071001295700201.png"\; state="\{\{state\}\}">c</figure-callout>}}_{F_{}}+{\mathrm{<figure-callout\; id="12"\; label="c\; F"\; filenames="C20071001295700201.png"\; state="\{\{state\}\}">c</figure-callout>}}_{F_{}}+\&CenterDot;\&CenterDot;\&CenterDot;+c_{F_{{1\mathrm{<figure-callout\; id="1"\; label="w"\; filenames="C20071001295700201.png"\; state="\{\{state\}\}">w</figure-callout>}}_1}}+{\mathrm{<figure-callout\; id="21"\; label="c\; F"\; filenames="C20071001295700201.png"\; state="\{\{state\}\}">c</figure-callout>}}_{F_{}}+{\mathrm{<figure-callout\; id="22"\; label="c\; F"\; filenames="C20071001295700201.png"\; state="\{\{state\}\}">c</figure-callout>}}_{F_{}}+\&CenterDot;\&CenterDot;\&CenterDot;+c_{F_{{2\mathrm{<figure-callout\; id="2"\; label="w"\; filenames="C20071001295700201.png"\; state="\{\{state\}\}">w</figure-callout>}}_2}}+{\mathrm{<figure-callout\; id="1"\; label="c\; F\; n"\; filenames="C20071001295700201.png"\; state="\{\{state\}\}">c</figure-callout>}}_{F_n}+{\mathrm{<figure-callout\; id="2"\; label="c\; F\; n"\; filenames="C20071001295700201.png"\; state="\{\{state\}\}">c</figure-callout>}}_{F_n}+\&CenterDot;\&CenterDot;\&CenterDot;+c_{F_{{\mathrm{nw}}_n}},$ Wherein, w _i(i=1 ..., be n) with x _iCarry out the number of times of translation transformation, d _Ij(i=1 ..., n, j=1 ..., w _i) be x _iSide-play amount when making translation transformation,

(i=1 ..., n, j=1 ..., w _i) be and x _i-d _IjCorresponding fuzzy subset is just comprising (P) and negative (N) two language values.

(i=1 ..., n, j=1 ..., w _i) be with Corresponding constant.

(2) among the If among state variable and input variable and the then output constant item all be optionally, but output item

(i=1 ..., n, j=1 ..., w _i) with input variable be one to one, if promptly partly comprise at If

(i=1 ..., n, j=1 ..., w _i), then should comprise in the then part ; If opposite If part does not comprise

Then should not comprise in the then part yet

.

This fuzzy rule base is total

Bar fuzzy rule, wherein w _i(i=1 ..., be n) with certain input variable x _iThe number of times of linear transformation promptly comprises all possible positive and negative combination in If part fuzzy variable, comprises all constant combinations at then part constant.

By the application of above-mentioned theory innovative approach, just can accurately detect the trailing edge of zero sequence ripple, thereby carry out short dot location, after the time difference that the zero sequence ripple propagates into the corresponding measuring point of first and last end is determined, just can realize locating short dot according to following formula $\mathrm{\&lambda;}=\underset{j=1}{\overset{r\left(d\right)}{\mathrm{\&Sigma;}}}{s}_j\&CenterDot;\frac{c_j}{r_j}---\left(17\right)$

Wherein, $c_j=\frac{l_{j.\min }}{l_j}$ Be the sensitivity coefficient of rule, promptly when this line failure, the possibility of reporting to the police; $r_j=\frac{l_{j+1.\max }-l_j}{l_j}$ Be the selection coefficient of rule, promptly when the line failure adjacent, the possibility of wrong report take place with this circuit; $s_j=\frac{\mathrm{Card}(X\&cap;Y)}{\mathrm{Card}\left(U\right)}$ Support weights for rule.

Advantage of the present invention is:

1 the present invention has adopted rough set theory that the fault sample collection is carried out the active domain that selection method is determined in data mining and Knowledge Discovery, redundant information is carried out Reduction of Knowledge, finally obtain the decision rule between fault-signal feature and selection method, and inharmonious decision rule is effectively handled by the expression-form of probability.

2 the present invention have proposed Intelligent Composite selection method and realization means thereof on the basis of harmonic analysis method in conjunction with the wavelet analysis method of transient process and zero sequence energy method.In Intelligent Composite route selection thought, every kind of selection method all carries out analytical calculation to fault data, draws a route selection result, and route selection result and intermediate data be sent to organize and coordinate layer.

3 the present invention have adopted based on the fault detect of fuzzy self-adaption reasoning and localization method.Whole fuzzy decision system comprises 4 major parts: data acquisition, the off-line learning of rule, the On-line Fuzzy decision-making of operation of power networks operating mode and comprehensively locate based on the fault point of Wavelet Transform.This localization method makes that fuzzy control rule is automatically adjusted, modification and perfect in control procedure, thereby the control performance of system is constantly improved, and reaches best control effect.

4 the present invention have adopted the wavelet filtering based on ANFIS, and the self adaptation that combines fuzzy hyperbolic tangent model becomes the yardstick wavelet transformation and carry out the identification of zero sequence ripple flex point, can accurately extract the characteristic point of signal---zero sequence ripple flex point.Adopted multiple mathematical algorithm to carry out the digitized processing of sampled data, selected suitable yardstick that analytic signal is implemented wavelet transform process, selected the wavelet analysis yardstick that is suitable for automatically with the rule base that fuzzy hyperbolic tangent model forms.

5 hardware systems of the present invention have adopted the hardware circuit design based on the Implementation of Embedded System mode.

Adopt the LPC2000 family chip in the hardware circuit design, further improved the integrated level of system; Voltage transformer, current transformer become and adopt the loop to separate, involving between having eliminated when adjusting multiplication factor mutually; Can detect automatically and switch for improving power frequency synchronous circuit that sampling precision (particularly to having the system of arc suppression coil) adopts, guaranteed the synchronous circuit fault after, system still can correctly sample; Selected the high-performance variable connector for use, antijamming capability strengthens greatly.

Description of drawings

Fig. 1 is a system architecture diagram;

Fig. 2 is the circuit theory diagrams of A/D conversion, AMR, DSP, lcd controller connection;

Fig. 3 is the circuit theory diagrams of preposition return circuit module filter circuit;

Fig. 4 is the circuit theory diagrams of memory module;

Fig. 5 is a general flow chart of the present invention;

Fig. 6 judges sub-process figure for faulty line;

Fig. 7 is harmonic analysis route selection sub-process figure;

Fig. 8 is quintuple harmonics route selection sub-process figure;

Fig. 9 is power direction method route selection sub-process figure;

Figure 10 is wavelet method route selection sub-process figure;

Figure 11 judges sub-process figure for fault distance;

Embodiment

The invention will be further described below in conjunction with accompanying drawing;

Data signal processor U1 selecting and purchasing with chip TMS320C5416, CPU module both among the present invention: embedded-type ARM microprocessor U2 selects chip S3C44BOX for use; The A/D modular converter is selected ADS7805 for use, and display module U4 selects KCS057QV1AJ for use; Latch is selected chip 74LS273 for use, and power module U6 selects AMC1117 for use, and the chip U7 that resets selects MAX811 for use, as shown in Figure 2.

Arm connects DSP: embedded-type ARM microprocessor S3C44BOX links to each other with D0, D1, D2, D3, D4, D5, D6, the D7 of S3C44BOX respectively with HD0, HD1, HD2, HD3, HD4, HD5, HD6, the HD7 of digital signal processor by TMS320C5416, this is the connected mode of a kind of HPI, the advantage of this mode is the logical circuit that does not need to add other, and is very convenient.

S3C44BOX is by all control register HCNTL1 and HCNTL0 of two address wire A3 and A2 addressing HPI mode.S3C44BOX solves eight port HD0, HD1, HD2, HD3, HD4, the HD5 of HPI, different these problems with the data bits of TMS320C5416 of data bits of HD6, HD7 by address wire A1, the former is 8, the latter is 16, when to the address of A1=0 write data, represent first byte, when to the address of A1=1 write data, represent second byte.

S3C44BOX links to each other by the HR/W of A4 pin and TMS320C5416, when A4=1, represents read operation, when A4=0, represents write operation.

AD connects the 16-bit fixed DSP TMS320C5416 of DSP:TI company, it is a kind of low energy-consumption electronic device, adopted improved Harvard structure, 1 program bus and 3 data/address buss are arranged, pile line operation has the instruction set of peripheral hardware and highly-specialised in the parallel hardware multiplier of highly-parallel 32-bit ALU, 16*16-bit, on-chip memory, the sheet.Crystal oscillator as the external 16MHZ of TMS320C5416, the work clock control model elects as * and 1, with ADS7805 /the CS pin receive DSP /the RD signal pins, in order to reduce control line, the CS pin directly is connected into low level, the R/C pin is received the expansion delivery outlet of DSP, gets final product and the BUSY signal is connected to common end inbound port.

ARM connects LCD display: KCS057QV1AJ and is produced by KYOCERA company, has 320 * 240 picture elements, band CFL STN (supertwist is to row) 256 look LCD display modules backlight.It is not with lcd controller, is easy to the lcd controller interface with S3C44BOX.

The external interface signals line that KCS057QV1AJ provides is as follows: FRM: the synchronous signal line of driver scanning; LOAD: data latch signal line; CP: data shift clock cable; DISP: display control signal line; D[7:0]: 8 video data incoming lines.

Between KCS057QV1AJ and lcd controller during wiring, the FRM of KCS057QV1AJ, LOAD, CP, D[7:0] respectively with VFRAME, VLINE, the VCLK of lcd controller, VD[7:0] link to each other.The DISP pin links to each other with the GPC15 of the GPIO of S3C44BOX, controls the opening and closing of LCD display module by GPC15.

What the keyboard operation module adopted is ARMSKY-4*4 determinant matrix keyboard module.

HT1380: clock module HT1380 links to each other with the XCLK pin of S3C44BOX by SCLK, for S3C44BOX provides clock signal.

MAX811: the chip MAX811 that resets links to each other with the nRest pin of S3C44BOX by pin RST.

The low current neutral grounding system fault route selecting device needs to receive in real time data, real-time judge, upload the failure line selection result in real time, be that typical a requirement is controlled in real time, the real-time system that handles, and the LPC2000 family chip is based on the ARM7TDMI-S CPU core, support ARM and Thumb instruction set, the integrated peripheral hardware that enriches in the chip, and has a low-down power consumption, make this Series of MCU be specially adapted to complex industrial control, mass data processing, occasion such as access control and signals collecting is guaranteeing that aspects such as system real time and stability are reasonable.Therefore, we also select the LPC2000 family chip as master chip.

The circuit theory diagrams of preposition return circuit module as shown in Figure 3, in actual applications, according to capacitance-resistance filter time constant formula τ=RC (unit is second) and relevant Fundamentals of Electronic Circuits knowwhy, according to time constant, the capacitance-resistance filter parameter of pressure signal is electric capacity and resistance, designed filter circuit can guarantee that detected signal passes through, and the high frequency or the low-frequency disturbance that will be lower than this time constant filter.Adopt the low pass capacitance-resistance filter to handle for analog signal, carry out shaping and denoising, I/O channel isolation etc. through photoelectric switch, make pulse signal be close to square wave, send into counter again and carry out data processing for traffic pulse.

The invention will be further described below in conjunction with accompanying drawing;

Specific embodiment 1:

The task that low-current ground fault line selection device need be finished is successively: the analog signal of the residual voltage of ARM collection bus and the zero-sequence current of each circuit, regulate its size by proper proportion and make it to become the treatable amplitude range of device, be converted into the digital signal that computing module can be discerned, DSP judges whether to break down according to certain algorithm principle analytic signal.If break down and provide the route selection result, preserve fault message, and send the route selection result to host computer and carry out fault alarm.

After the bus residual voltage of system and the conversion of the zero-sequence current of each circuit process voltage transformer summation current transformer, import preposition return circuit module, the voltage and current signal is through after the high-precision voltage transformer summation current transformer further conversion, and signal becomes-and 5V is to the voltage signal of+5V; Voltage signal disturbs by low pass filter filters out, the voltage analog signal of output smoothing, and system monitors each circuit phase current by the residual voltage and the phase voltage of the sampling apparatus on-line monitoring system of A/D modular converter.With residual voltage, the variation of zero-sequence current is as the entry condition of fault.

In small current neutral grounding system, when the metallicity single phase ground fault took place, the ground connection phase voltage was reduced to 0, and the two-way phase voltage of normal operation raise for line voltage be phase voltage Doubly.Simultaneously, residual voltage on the circuit and zero-sequence current all can increase, the phase voltage when wherein the amplitude of residual voltage equals operate as normal.Therefore, can utilize residual voltage and zero-sequence current to surpass the entry condition of certain threshold as single phase ground fault,

S ₀＞S _0d (18)

Used residual voltage and zero-sequence current can be that the result who directly measures calculates by three-phase voltage or electric current:

$s_0\left(t\right)=\frac{1}{3}(s_A\left(t\right)+s_B\left(t\right)+s_C\left(t\right))---\left(19\right)$

S in above-mentioned two formulas has represented voltage or electric current.

When there was transition resistance in earth point, residual voltage reduced along with the increase of transition resistance.The influence of unbalance voltage when overcoming operate as normal simultaneously, the threshold of residual voltage generally is taken as 20% of phase voltage.

In each sampling period, judge whether neutral point voltage is out-of-limit, if its absolute value surpasses threshold value, device starts, continuation stops sampling after gathering some points, keeps data, stores memory module into.

After detecting fault, just can carry out accident analysis and judged according to being retained in these data in the internal memory.

Route selection process: the two-dimensional array of the sub-thread creation 1000*64 that samples, real storage storage when being used for data are carried out, cover from the circulation of data top after being filled with, break down back (greater than 6 points of starting resistor) with preceding 100 groups of data in the array and back 200 groups of data as transient voltage, to the 500 groups of data in back again as steady state data, submit to data main thread to carry out failure line selection.After 1 second,, then continue to extract 500 points, submit to main thread to carry out continuous route selection as steady state data if fault does not disappear.Carry out feature extraction then, carry out degree of membership and calculate and final decision, obtain the route selection result.Is example explanation route selection process with colony than width of cloth phase comparing method: extract 3 circuits of electric current maximum, and to establish initial accumulated value be s1, and s2 s3, s. carries out the pointwise comparison with these 3 electric current arrays and voltage array, and is opposite with voltage sign, then the s absolute value that directly adds up; Identical with voltage sign, the s absolute value that adds up then; Article 3, line voltage distribution is all identical with current symbol, and then s (bus) is set as a higher value with s1, s2 s3, and s (bus) compares, and what value was maximum is exactly faulty line.Respectively with having power direction method, harmonic analysis method (being that colony is than width of cloth phase comparing method) quintuple harmonics method, wavelet method to carry out route selection, for the comprehensive selection of each criterion of distribution circuit single-phase earth fault, we will differentiate weight by fault data $\mathrm{\&lambda;}=\underset{j=1}{\overset{r\left(d\right)}{\mathrm{\&Sigma;}}}{s}_j\&CenterDot;\frac{c_j}{r_j}---\left(20\right)$

As criterion.Adopt rough set theory that the fault sample collection is carried out the active domain that selection method is determined in data mining and Knowledge Discovery, for the comprehensive selection of each criterion of distribution circuit single-phase earth fault.Determine result of decision space D={d ₁, d ₂..., d _i..., d _n, current running status belongs to each fuzzy subset's degree of membership E={e ₀, e ₁..., e _k..., e _V-1, the degree of membership that each class result of decision belongs to each fuzzy subset of its correspondence is F={f ₀, f ₁..., f _k..., f _U-1.

When DSP receives after ARM passes the fault data come, just can start the wavelet analysis program and distinguish the computational analysis of fault localization.The range finding formula is: x=v Δ t/2 (21)

The correct wavelet transform dimension a that selects, the rule base that this project adopts fuzzy hyperbolic tangent model to form is selected suitable yardstick.Can accurately detect the trailing edge of zero sequence ripple, the selection result (digital quantity, 0 representative is not a fault wire, 1 represent fault wire) and the result that finds range be outputed to display unit thereby carry out short dot location 8.Start alarm then, notify the operator on duty.After pending fault was got rid of, device detected residual voltage and is lower than the startup threshold values, and relay recovery normal condition, program are jumped out the route selection flow process, get back to detected state.The Matcom that the wavelet analysis programming adopts MathTools company to release, it can be translated into the source code of Matlab the C++ source code of same function, has both kept the good algorithm of Matlab, has kept the height of C++ to carry out efficient again.Therefore, we only need write route selection and the ranging process * .m program file of pairing MATLAB separately, change into the C++ program file then in visual c++ 6.0 translation and compiling environments.Such programming mode is very succinct, very easy realizations such as the wavelet function of choosing in the modification * .m file, decomposition scale, but also can be by MATLAB and the powerful graphics system of visual c++, fault after the diagnosis is carried out the demonstration of image, and for example waveform shows and the demonstration of geography information.

This device can be applied to distribution system 10KV transformer station and factory provides transformer station for oneself.This device is installed on 10KV bus zero sequence transformer secondary circuit interface in distribution system 10KV transformer station.The difference of the two is the difference of electric pressure.When fault or fluctuation took place, display unit demonstrated result of decision space D={d ₁, d ₂..., d _i..., d _n, current running status belongs to each fuzzy subset's degree of membership E={e ₀, e ₁..., d _k..., e _V-1, the degree of membership that each class result of decision belongs to each fuzzy subset of its correspondence is F={f ₀, f ₁..., f _k..., f _W-1, and final route selection result and range finding result, and start warning.

Claims (1)

1, a kind of low current grounding detects and the device of locating, and it is characterized in that this device comprises slave computer and the host computer of being made up of CPU module, DSP, preposition return circuit module, A/D modular converter, memory module, Display And Keyboard operational module, communication module; Wherein preposition return circuit module, the A/D modular converter, the CPU module, DSP connects successively, memory module, the Display And Keyboard operational module, communication module links to each other with the CPU module respectively, host computer links to each other with communication module, the analog signal of the residual voltage of CPU module collection bus and the zero-sequence current of each circuit, regulate its size in proportion and make it to become the treatable amplitude range of device, be converted into the digital signal that the CPU module can be discerned, by the DSP analytic signal, judge whether to break down, provide the route selection result if break down, preserve fault message, and send the route selection result to host computer and carry out fault alarm;

Described CPU module adopts embedded-type ARM microprocessor S3C44BOX (U1), HD0, the HD1 of S3C44BOX (U1), HD2, HD3, HD4, HD5, HD6, HD7 link to each other with D0, D1, D2, D3, D4, D5, D6, the D7 of DSP digital signal processor TMS320C5416 (U2) respectively, and HCNTL1, the HCNTL0 of S3C44BOX (U1), HBIL, HR/W, nWE, nOE, nGCS1 link to each other with A3, A2, A1, A4, HDS2, HDS1, the HCS of TMS320C5416 (U2) respectively; VCLK, the VD0 of TMS320C5416 (U2), VD1, VD2, VD3, VD4, VD5, VD6, VD7, GPC15, VFRAME, VLINE link to each other with CP, VK0, VK1, VK2, VK3, VK4, VK5, VK6, VK7, DISP, FRM, the LOAD of LCD display interface chip KCS057QV1AJ (U4) in keyboard and the display module respectively; The chip MAX811 (U7) that resets links to each other with the nRest pin of TMS320C5416 (U2) by pin RST; D0～D15 of A/D modular converter ADS7805 (U3) links to each other with D0～D15 of S3C44BOX (U1) by the D0 of latch 74LS273 (U5), the BUSY of A/D modular converter ADS7805 (U3) links to each other with the IO2 of S3C44BOX (U1), and the output end vo ut of power supply chip AMC1117 (U6) provides 1.8V power supply.

Images