CN105717414A - Ground fault positioning method and device based on zero sequence mutation method and vector method - Google Patents

Abstract

The invention discloses a ground fault positioning method and device based on a zero sequence mutation method and a vector method. The device comprises an overhead current acquisition unit, a data merging communication unit and an upper computer device; the overhead current acquisition unit is connected with the data merging communication unit via a 2.4G communication circuit; and the data merging communication unit is connected with the upper computer device via a GPRS (General Packet Radio Service) module. According to the ground fault positioning device based on a zero sequence mutation method and a vector method, the current acquisition unit with phases A, B and C at different program addresses are adopted and divided into A, B and C phase acquisition indication units, and the non-three-phase program addresses are consistent, so that the acquired current information carries an amplitude parameter and a phase angle parameter, the judgment probability of ground faults of a low current grounding system can be improved, faults can be judged more accurately, and the fault judgment probability can be improved; and the requirements of different grounding systems are met by adopting a fault judgment mechanism combining the zero sequence mutation method and the vector method.

Description

Earth design method and device based on zero sequence sudden change method and vector method

Technical field

The present invention relates to a kind of low current grounding localization method, specifically, relate to the Earth design method of a kind of suddenly change based on zero sequence method and vector method.

Background technology

Middle voltage distribution networks wiring is complicated, and branch is more, is mostly singlephase earth fault in line fault.The middle voltage distribution networks majority of China adopts neutral by arc extinction coil grounding system and isolated neutral system.The distribution network systems of both ground connection is otherwise known as small current neutral grounding system.After small current neutral grounding system generation singlephase earth fault, will not forming short-circuit loop, only be caused only small earth current by the distribution capacity of system, three-phase line voltage continues to keep symmetry, and system can charging operation 1-2 hour.Owing to the earth current of small current neutral grounding system is faint, this is determined that earth fault brings difficulty, here it is why distribution singlephase earth fault location becomes a well-known difficult problem.

Existing small-current failure location system method has: passive transient method and the big class of active injection method two.

The practical traditional electrical pure iron of the current data harvester of existing fault location system is as magnetic circuit sensing device, when electrical pure iron senses as magnetic circuit, precision is very low, it is difficult to reflect accurately the electric current actual change of power circuit, cannot judge that the fault of circuit occurs accurately.Data merge in communication device cannot synthesize zero-sequence current, it is impossible to calculate initial phase angle, so former technical scheme is difficult to catch fault message accurately.Technical data originally merges communication device and does not have breakdown judge ability, only has communication function.

The carrier phase shift of A, B, C phase 120 ° in power system, and prior art, the amplitude of each phase current can be gathered, can not effectively distinguish phase relation, it is impossible to by the method failure judgement of zero sequence stable state, can only be that monitoring current exceedes certain value and just reports fault, breakdown judge inaccuracy.

Passive transient current method: transient current ratio juris is that the current value increased by moment is compared with setting value, no matter is short circuit current or earth current, breaks down as long as being more than setting value within the time of regulation.This kind of system generally uses the fault detect of simple in construction to pop one's head in, probe accuracy of detection non-normally low, have even as low as about 20%, cause in use breakdown judge instruction accuracy less than 40%.This kind of system is often with low cost, but accuracy is too low, is commercially realized, and will be gradually backed out market.This kind of system is because of the limitation of its principle, it is impossible to be operated in arc suppression coil earthing system.

Active injection method: injecting ratio juris is increase signal PT in station, when earth fault occurs, automatic activation signal PT injects the half-wave voltage signal of 60Hz to all of circuit, the fault detector that can receive this signal is reported to the police, and the indicator interval do not reported to the police with the next one of last warning is fault section.Though the system of injection method can adapt to different earthed systems, but the method lost efficacy in electrical network dry, that transition resistance is big, branch is more.And the use of signal PT is likely to introduce harmonic wave and jeopardizes network system.The fault location system price of injection method is significantly high, increases operation cost.

Summary of the invention

For above-mentioned deficiency of the prior art, the present invention provides a kind of different earthed system requirement that meets, and improves the Earth design method of suddenly change based on zero sequence method and the vector method of breakdown judge probability.

The technical solution used in the present invention is:

The Earth design method of a kind of suddenly change based on zero sequence method and vector method, comprises the steps:

In setting transformer station, PT residual voltage is than logarithm value USET；

Read PT residual voltage UO1 in transformer station；

Judge in transformer station PT residual voltage UO1 whether more than PT residual voltage than logarithm value USET；

In transformer station, PT residual voltage UO1 is more than PT residual voltage than logarithm value USET, sends out zero-sequence current sample command to each node, otherwise continues to read PT residual voltage UO1 in transformer station；

Obtain n node zero-sequence current numerical value IO1-IOn；

Judge whether zero-sequence current obtains complete；

Zero-sequence current obtains complete, it is judged that earthing type, otherwise continues to obtain node zero-sequence current numerical value；

Determine that earthing type is arc suppression coil；It is transmitted across compensating regulating command to arc suppression coil；

Again read off the residual voltage UO2 of system；

Again issue zero-sequence current sample command；

Obtain n node zero-sequence current IO1-IOn；

Suddenly change and mensuration calculate faulty line trouble point；Single-phase earthing alarm command is sent out along the line to fault；

Earthing type is non-arc suppression coil；Taking the maximum circuit of zero sequence is faulty line；

Zero sequence vector method orients trouble point；

Single-phase earthing alarm command is sent out along the line to fault.

A kind of earth fault positioning device of suddenly change based on zero sequence method and vector method, including:

For obtaining the built on stilts current acquisition unit of n node zero-sequence current numerical value IO1-IOn；

The data gathered being carried out waveform reduction, calculates the amplitude of average current value, calculate the initial phase angle of sampling every time, the data calculating synthesis zero-sequence current merge communication unit；

Than logarithm value USET, PT residual voltage UO1 in transformer station is read for setting PT residual voltage in transformer station；Adopt sudden change mensuration and zero sequence vector method calculates faulty line trouble point, the traversal identification according to trouble point in system Yu non-faulting point, it is judged that fault section, send out single-phase earthing alarm command the host computer shown over the display to fault along the line.

Described data merge communication unit and include casing and case lid, and described casing both sides are provided with fixing hanger, and fixing hanger is provided with earhole, and two free ends of U-shaped snap ring are connected with earhole by nut；Described case lid is connected with casing by hinge axis；Being provided with solar panel on described case lid, described case lid surface configuration has support ear；It is provided with engaging lug bottom described solar panel；Support ear and engaging lug are provided with connecting hole；Described support ear and engaging lug distribution triangular in shape, upper support ear is connected with engaging lug；Supported underneath ear is connected with engaging lug by bracing frame.

Described data merge communication unit and include: for the 2.4G communicating circuit with built on stilts current acquisition unit communications；For the GPRS module with host computer device communication.

Described built on stilts current acquisition unit includes solar panel, and solar panel is connected with power taking accumulator；Power taking accumulator is connected with Open Type Electric Current Mutual Inductor, current sampling circuit, low-power consumption monolithic processor, failure indicating circuit and 2.4G communicating circuit；Open Type Electric Current Mutual Inductor is connected with the preposition decision circuitry of short circuit, current sampling circuit；Low-power consumption monolithic processor is connected with the preposition decision circuitry of short circuit and current sampling circuit；Low-power consumption monolithic processor is connected with failure indicating circuit and 2.4G communicating circuit.

Described data merge flush bonding processor, electric voltage observation circuit and the power supply operation indicating circuit that communication unit includes being arranged in casing.

Described data merge communication unit and include charge management circuit, and charge management circuit and solar panel and maintenance-free battery phase and discharge protection circuit are connected；Discharge protection circuit is connected with run switch and electric voltage observation circuit.

The beneficial effect of hinge structure of the present invention:

The present invention is based on the Earth design method of zero sequence sudden change method and vector method, it is possible to increase the judgement probability of small current neutral grounding system generation earth fault, and price is cheaply more a lot of than active injection method, and system interference is few.The present invention takes into account load monitoring function simultaneously, facilitates the load condition of information rack ceases to be busy.

The present invention, by earthing type in addition subregion, because different earthing types has distinctive earth fault feature itself, because of its feature selection diverse ways, thus can judge fault, according to high breakdown judge probability more accurately.

Invention adopts the current acquisition unit that A, B, C phase is different, application collecting unit is divided into A, B, C phase acquisition indicating member, non-three-phase program address is consistent, make in the current information gathered not only with magnitude parameters, also with the parameter at phase angle, so be conducive to using the sudden change that the present invention uses mensuration, and vector method, breakdown judge is more accurate.

The breakdown judge mechanism that application zero sequence sudden change method and vector method combine, meets different earthed system requirements.

Accompanying drawing explanation

Fig. 1 this utility model is based on the system architecture diagram of zero sequence sudden change method and the earth fault positioning device of vector method；

Fig. 2 this utility model is based on the breakdown judge flow chart of zero sequence sudden change method and the earth fault positioning device of vector method；

Fig. 3 utility model is based on the isolated neutral system earth fault zero sequence isoboles of zero sequence sudden change method and the earth fault positioning device of vector method；

Fig. 4 utility model is based on the zero-sequence network figure after the arc suppression coil parameter change of zero sequence sudden change method and the earth fault positioning device of vector method；

Fig. 5 utility model is based on the zero-sequence network figure before the arc suppression coil parameter change of zero sequence sudden change method and the earth fault positioning device of vector method；

Fig. 6 utility model is based on the system block diagram of the built on stilts net collection indicating member of the earth fault positioning device of zero sequence sudden change method and vector method；

Fig. 7 utility model merges communication unit system diagram based on the data of zero sequence sudden change method and the earth fault positioning device of vector method；

Fig. 8 utility model is based on the main TV structure schematic diagram of the data merging communication unit of zero sequence sudden change method and the earth fault positioning device of vector method；

Fig. 9 utility model is based on the side-looking structural representation of the data merging communication unit of zero sequence sudden change method and the earth fault positioning device of vector method；

Figure 10 utility model is based on the perspective view of the data merging communication unit of zero sequence sudden change method and the earth fault positioning device of vector method.

Critical piece symbol description in accompanying drawing:

In figure:

1GPS antenna

22.4G antenna

3GPRS antenna

4 data merge communication controller

5 fixing hangers

6 engaging lugs

7U type snap ring

8 casings

9 solar panels

10 bracing frames

11 run switchs.

12 electric fuses.

13 accumulator

14 support ears

15 case lids.

Detailed description of the invention

Referring to drawings and Examples, the present invention will be described in detail:

Electric pole is embraced in wherein, playing the effect of fixing device by U-shaped snap ring.

Pulling down during bracing frame transport, foldable solar energy plate, transportation volume is minimum.

Accompanying drawing 1-10, it can be seen that the Earth design method of a kind of suddenly change based on zero sequence method and vector method, comprises the steps:

In setting transformer station, PT residual voltage is than logarithm value USET；

Read PT residual voltage UO1 in transformer station；

Judge in transformer station PT residual voltage UO1 whether more than PT residual voltage than logarithm value USET；

In transformer station, PT residual voltage UO1 is more than PT residual voltage than logarithm value USET, sends out zero-sequence current sample command to each node, otherwise continues to read PT residual voltage UO1 in transformer station；

Obtain n node zero-sequence current numerical value IO1-IOn；

Judge whether zero-sequence current obtains complete；

Zero-sequence current obtains complete, it is judged that earthing type, otherwise continues to obtain node zero-sequence current numerical value；

Determine that earthing type is arc suppression coil；It is transmitted across compensating regulating command to arc suppression coil；

Again read off the residual voltage UO2 of system；

Again issue zero-sequence current sample command；

Obtain n node zero-sequence current IO1-IOn；

Suddenly change and mensuration calculate faulty line trouble point；Single-phase earthing alarm command is sent out along the line to fault；

Earthing type is non-arc suppression coil；Taking the maximum circuit of zero sequence is faulty line；

Zero sequence vector method orients trouble point；

Single-phase earthing alarm command is sent out along the line to fault.

A kind of earth fault positioning device of suddenly change based on zero sequence method and vector method, including:

For obtaining the built on stilts current acquisition unit of n node zero-sequence current numerical value IO1-IOn；

The data gathered being carried out waveform reduction, calculates the amplitude of average current value, calculate the initial phase angle of sampling every time, the data calculating synthesis zero-sequence current merge communication unit；

Than logarithm value USET, PT residual voltage UO1 in transformer station is read for setting PT residual voltage in transformer station；Adopt sudden change mensuration and zero sequence vector method calculates faulty line trouble point, the traversal identification according to trouble point in system Yu non-faulting point, it is judged that fault section, send out single-phase earthing alarm command the host computer shown over the display to fault along the line.

Described data merge communication unit and include casing 8 and case lid 15, and described casing 8 both sides are provided with fixing hanger 5, and fixing hanger 5 is provided with earhole, and 7 two free ends of U-shaped snap ring are connected with earhole by nut；Described case lid 15 is connected with casing by hinge axis；Being provided with solar panel 9 on described case lid 15, described case lid 15 surface configuration has support ear 14；It is provided with engaging lug 6 bottom described solar panel 9；Support ear 14 and engaging lug 6 are provided with connecting hole；Described support ear 14 and engaging lug 6 distribution triangular in shape, upper support ear is connected with engaging lug；Supported underneath ear is connected with engaging lug by bracing frame 10.

Described data merge communication unit and include: for the 2.4G communicating circuit with built on stilts current acquisition unit communications；For the GPRS module with host computer device communication.

Described built on stilts current acquisition unit includes solar panel, and solar panel is connected with power taking accumulator；Power taking accumulator is connected with Open Type Electric Current Mutual Inductor, current sampling circuit, low-power consumption monolithic processor, failure indicating circuit and 2.4G communicating circuit；Open Type Electric Current Mutual Inductor is connected with the preposition decision circuitry of short circuit, current sampling circuit；Low-power consumption monolithic processor is connected with the preposition decision circuitry of short circuit and current sampling circuit；Low-power consumption monolithic processor is connected with failure indicating circuit and 2.4G communicating circuit.

Described data merge flush bonding processor, electric voltage observation circuit and the power supply operation indicating circuit that communication unit includes being arranged in casing.

Described data merge communication unit and include charge management circuit, and charge management circuit and solar panel and maintenance-free battery phase and discharge protection circuit are connected；Discharge protection circuit is connected with run switch and electric voltage observation circuit.

Such as Fig. 2 breakdown judge schematic flow sheet.

This flow process starts from step s201.

Then step s202, reads PT residual voltage UO1 in transformer station.

In step s203, it is judged that in transformer station PT residual voltage UO1 whether more than PT residual voltage than logarithm value USET；In transformer station, PT residual voltage UO1 is more than PT residual voltage than logarithm value USET, performs step s204, otherwise performs step s202.

In step s204, send out zero-sequence current sample command to each node.

In step s205, obtain n node zero-sequence current numerical value IO1-IOn.

In step s206, it is judged that it is complete whether zero-sequence current obtains；Zero-sequence current obtains complete, performs step s207, otherwise performs step s205.

In step s207, it is judged that earthing type, earthing type is arc suppression coil, performs step s209, otherwise performs step s208.

In step s209, it is transmitted across compensating regulating command to arc suppression coil.

In step s210, again read off the residual voltage UO2 of system.

In step s211, again issue zero-sequence current sample command.

In step s212, obtain n node zero-sequence current IO1-IOn.

In step s213, suddenling change mensuration calculates faulty line trouble point；Perform step s215.

In step s208, taking the maximum circuit of zero sequence is faulty line.

In step s214, zero sequence vector method orients trouble point.

In step s215, send out single-phase earthing alarm command along the line to fault.

Flow process ends at step s216.

In n the node of Fig. 1, each node is gathered indicating member by a data combination unit and ABC and forms.

Fig. 6, in 7, dotted line represents energy Flow route, and solid line represents data glide path.

The present invention is as follows based on the Earth design method work process of zero sequence sudden change method and vector method:

Before sampling, data combination unit uses GPS time service module that three sampling units are carried out standard time checking, then A, B, C phase acquisition indicating member merges communication unit data by 2.4G module with data to be transmitted, (20ms is a cycle to the data of 10 cycles of sampled acquisition each time, each cycle gathers 16 points, constitute sinusoidal wave form), 160 data gathered are carried out waveform reduction by data combination unit, then the amplitude of average current value is calculated, calculate the initial phase angle of sampling every time, calculate synthesis zero-sequence current, data combination unit draws whether break down according to sequential operation.

Data combination unit uses the remote data transmission function of GPRS module, and load current data are sent to host computer, and host computer displays；SOE data message is sent to host computer after occurring by fault, the host computer traversal identification according to trouble point in system Yu non-faulting point, it is judged that fault section, and shows over the display.

Built on stilts current acquisition unit includes: A, B, C three-phase collecting unit, and collecting unit is responsible for gathering current information and is sent to data merging communication unit, uses from circuit and solar energy power taking supply itself, luminous or reproduction instruction fault message.

The square indicating ABC in Fig. 1 gathers indicating member exactly, gather indicating member to be made up of open-type transformer, sampling circuit plate, power taking wiring board, solar charging circuit, malfunction coefficient part etc., the digital quantity that sampling circuit plate is changed to voltage by using AD circuit the analog quantity of electric current to be filled, single-chip microcomputer gathers the data of AD and is this moment current data.Charging circuit be collected by transformer induced go out electricity, these electricity are stored in energy-storage travelling wave tube, for wiring board.Solar charging circuit is also such.Malfunction coefficient part is divided into LED flash of light display and reproduction instruction (red label rotates, escape block board reveal).

Sending electric current: 2.4G module, data are transmitted.

Data merge communication unit and include: solar electric power supply system, GPRS communication, 2.4G communication, gps satellite time service, merge communication unit to be responsible for by completing the collection to current amplitude and phase angle information with GPS time service, use GPRS low-power consumption module that the data processed are reported host computer.

Host computer device includes: server host, sending short messages in groups device, 3G route device, upper computer software, and host computer is responsible for collecting the various data merging communication unit, the various parameter of remote regulating, display information on load and fault message.

The judge process of zero-sequence current vector method is as follows:

Fig. 3 is isolated neutral system earth fault zero sequence isoboles, and this system has n bar outlet, and A phase resistance grounded fault occurs on outlet n, and ground connection excessive resistance is R.Trouble point is F, and faulty line is divided into front and back two parts, respectively with x, y symbology.Zl～Zn represents the circuit 1 load to circuit n successively.

It is earth-free owing to distribution becomes on high-tension side neutral point, so high-pressure side three-phase load electric current sum is zero, namelyThe each phase current in outlet 1 exit is equal to load current and this phase capacitance current sum of this circuit again, namely

$\left\{\begin{array}{c}{\stackrel{\·}{I}}_{a1}={\stackrel{\·}{U}}_a{\mathrm{j\ωc}}_1+{\stackrel{\·}{I}}_{\mathrm{al}1}\\ {\stackrel{\·}{I}}_{b1}={\stackrel{\·}{U}}_b{\mathrm{j\ωc}}_1+{\stackrel{\·}{I}}_{\mathrm{bl}1}\\ {\stackrel{\·}{I}}_{c1}={\stackrel{\·}{U}}_c{\mathrm{j\ωc}}_1+{\stackrel{\·}{I}}_{\mathrm{cl}1}\end{array}\right.---\left(1\right)$

Again ${\stackrel{\·}{I}}_{01}=({\stackrel{\·}{I}}_{a1}+{\stackrel{\·}{I}}_{b1}+{\stackrel{\·}{I}}_{c1})/3=({\stackrel{\·}{U}}_a+{\stackrel{\·}{U}}_b+{\stackrel{\·}{U}}_c){\mathrm{j\ωc}}_1/3+({\stackrel{\·}{I}}_{\mathrm{al}1}+{\stackrel{\·}{I}}_{\mathrm{al}1}+{\stackrel{\·}{I}}_{\mathrm{al}1})/3={\stackrel{\·}{U}}_0{\mathrm{j\ωc}}_{\text{1}}$

From mains side, according to Kirchhoff's current law (KCL), outlet n the zero-sequence current having be all healthy phases electric currents and, namely

${\stackrel{\·}{I}}_{0n}=\underset{i=1}{\overset{n-1}{\mathrm{\Σ}}}{I}_{0i}={\stackrel{\·}{U}}_0\underset{i=1}{\overset{n-1}{\mathrm{\Σ}}}{\mathrm{j\ωc}}_i---\left(2\right)$

From line side, each phase current on outlet n is

$\left\{\begin{array}{c}{\stackrel{\·}{I}}_{a1}={\stackrel{\·}{U}}_a{\mathrm{j\ωc}}_n+{\stackrel{\·}{I}}_{a\ln }\\ {\stackrel{\·}{I}}_{b1}={\stackrel{\·}{U}}_b{\mathrm{j\ωc}}_n+{\stackrel{\·}{I}}_{b\ln }\\ {\stackrel{\·}{I}}_{c1}={\stackrel{\·}{U}}_c{\mathrm{j\ωc}}_n+{\stackrel{\·}{I}}_{c\ln }\end{array}\right.---\left(3\right)$

Have formula (3) can the zero-sequence current of outlet n

${\stackrel{\·}{I}}_{0n}={\stackrel{\·}{U}}_0{\mathrm{j\ωc}}_n+{\stackrel{\·}{U}}_a/3R={\stackrel{\·}{U}}_0{\mathrm{j\ωc}}_n+({\stackrel{\·}{U}}_0+E_a)/3R---\left(4\right)$

Association type

$-E_a={\stackrel{\·}{U}}_0+{\stackrel{\·}{U}}_0\underset{i=1}{\overset{n}{\mathrm{\Σ}}}{\mathrm{j\ωc}}_i\·3R={\stackrel{\·}{U}}_0+{\stackrel{\·}{U}}_0{\mathrm{j\ωc}}_{\mathrm{all}}\·3R---\left(5\right)$

Wherein c_allFor all capacitive earth current sums.

By analyzing the Some features drawing isolated neutral system singlephase earth fault above:

(1) zero sequence equivalent network is mainly made up of the distribution capacity over the ground of circuit, and the capacitive earth current of circuit constitutes the zero-sequence current of each bar circuit.

(2) owing to the zero-sequence current on circuit is less, therefore the residual voltage approximately equal of each point on circuit, the residual voltage of the whole network is approximately same value.

(3) the zero-sequence current size of non-faulting outlet and the direct-to-ground capacitance of residual voltage, this circuit are directly proportional.The zero-sequence current in faulty line exit equal to non-fault line zero-sequence current and.With bus to the direction of circuit for zero-sequence current positive direction, the zero-sequence current of non-faulting outlet is electric current positive direction, the advanced residual voltage of zero-sequence current 90 ° of non-faulting outlet, faulty line exit zero-sequence current delayed phase residual voltage 90 °.

(4) from current trend it can also be seen that be gradually increased along failure path zero-sequence current, maximum before trouble point；Behind trouble point, than before trouble point, zero-sequence current is little a lot, and is the positive direction of zero-sequence current along circuit positive direction, the delayed residual voltage of zero-sequence current 90 ° on failure path, the advanced residual voltage of zero-sequence current 90 ° in non-faulting path.

(5) size of ground fault resistance only affects the size of residual voltage and zero-sequence current, has no effect on the phase relation between residual voltage and zero-sequence current.

The mensuration judge process that suddenlys change is as follows:

Suddenly change and mensuration be primarily directed to neutral by arc extinction coil grounding system fault locating method.Fig. 2 Fig. 3 is the zero-sequence network figure that arc suppression coil parameter change is forward and backward respectively, and wherein f point breaks down.

In Fig. 4, Fig. 5, the zero-sequence current of non-faulting non-fault line is respectively as follows:

$\left\{\begin{array}{c}{\stackrel{\·}{I}}_{11}={\stackrel{\·}{U}}_1{\mathrm{j\ωc}}_1\\ {\stackrel{\·}{I}}_{21}={\stackrel{\·}{U}}_1{\mathrm{j\ωc}}_2\\ {\stackrel{\·}{I}}_{31}={\stackrel{\·}{U}}_1{\mathrm{j\ωc}}_3\end{array}\right.---\left(6\right)$ $\left\{\begin{array}{c}{\stackrel{\·}{I}}_{12}={\stackrel{\·}{U}}_2{\mathrm{j\ωc}}_1\\ {\stackrel{\·}{I}}_{22}={\stackrel{\·}{U}}_2{\mathrm{j\ωc}}_2\\ {\stackrel{\·}{I}}_{32}={\stackrel{\·}{U}}_2{\mathrm{j\ωc}}_3\end{array}\right.---\left(7\right)$

In Fig. 4 and Fig. 5, on faulty line, each branch road capacitive earth current is respectively as follows:

$\left\{\begin{array}{c}{\stackrel{\·}{I}}_{\mathrm{ab}1}={\stackrel{\·}{U}}_1{\mathrm{j\ωc}}_{\mathrm{ab}}\\ {\stackrel{\·}{I}}_{\mathrm{bc}1}={\stackrel{\·}{U}}_1{\mathrm{j\ωc}}_{\mathrm{bc}}\\ {\stackrel{\·}{I}}_{\mathrm{bf}1}={\stackrel{\·}{U}}_1{\mathrm{j\ωc}}_{\mathrm{bf}}\\ {\stackrel{\·}{I}}_{\mathrm{fd}1}={\stackrel{\·}{U}}_1{\mathrm{j\ωc}}_{\mathrm{fd}}\end{array}\right.---\left(8\right)$ $\left\{\begin{array}{c}{\stackrel{\·}{I}}_{\mathrm{ab}2}={\stackrel{\·}{U}}_2{\mathrm{j\ωc}}_{\mathrm{ab}}\\ {\stackrel{\·}{I}}_{\mathrm{bc}2}={\stackrel{\·}{U}}_2{\mathrm{j\ωc}}_{\mathrm{bc}}\\ {\stackrel{\·}{I}}_{\mathrm{bf}2}={\stackrel{\·}{U}}_2{\mathrm{j\ωc}}_{\mathrm{bf}}\\ {\stackrel{\·}{I}}_{\mathrm{fd}2}={\stackrel{\·}{U}}_2{\mathrm{j\ωc}}_{\mathrm{fd}}\end{array}\right.---\left(9\right)$

In Fig. 4, Fig. 5, the inductive current of arc suppression coil is

${\stackrel{\·}{I}}_{L1}=-{\stackrel{\·}{U}}_1/{\mathrm{j\ωL}}_1---\left(10\right)$ ${\stackrel{\·}{I}}_{L2}=-{\stackrel{\·}{U}}_2/{\mathrm{j\ωL}}_1---\left(11\right)$

The zero-sequence current of each monitoring point on faulty line in Fig. 4, Fig. 5

$\left\{\begin{array}{c}{\stackrel{\·}{I}}_{\mathrm{abs}1}={\stackrel{\·}{I}}_{L1}-{\stackrel{\·}{I}}_{11}-{\stackrel{\·}{I}}_{21}-{\stackrel{\·}{I}}_{31}\\ {\stackrel{\·}{I}}_{\mathrm{abe}1}={\stackrel{\·}{I}}_{\mathrm{abs}1}-{\stackrel{\·}{I}}_{\mathrm{ab}1}\\ {\stackrel{\·}{I}}_{\mathrm{bfs}1}={\stackrel{\·}{I}}_{\mathrm{abe}1}-{\stackrel{\·}{I}}_{\mathrm{bc}1}\\ {\stackrel{\·}{I}}_{\mathrm{bfe}1}={\stackrel{\·}{I}}_{\mathrm{bfs}1}-{\stackrel{\·}{I}}_{\mathrm{bf}1}\\ {\stackrel{\·}{I}}_{\mathrm{bcs}1}={\stackrel{\·}{I}}_{\mathrm{bc}1}\\ {\stackrel{\·}{I}}_{\mathrm{fds}1}={\stackrel{\·}{I}}_{\mathrm{fd}1}\end{array}\right.---\left(12\right)$ $\left\{\begin{array}{c}{\stackrel{\·}{I}}_{\mathrm{abs}2}={\stackrel{\·}{I}}_{L2}-{\stackrel{\·}{I}}_{12}-{\stackrel{\·}{I}}_{22}-{\stackrel{\·}{I}}_{32}\\ {\stackrel{\·}{I}}_{\mathrm{abe}2}={\stackrel{\·}{I}}_{\mathrm{abs}2}-{\stackrel{\·}{I}}_{\mathrm{ab}2}\\ {\stackrel{\·}{I}}_{\mathrm{bfs}2}={\stackrel{\·}{I}}_{\mathrm{abe}2}-{\stackrel{\·}{I}}_{\mathrm{bc}2}\\ {\stackrel{\·}{I}}_{\mathrm{bfe}2}={\stackrel{\·}{I}}_{\mathrm{bfs}2}-{\stackrel{\·}{I}}_{\mathrm{bf}2}\\ {\stackrel{\·}{I}}_{\mathrm{bcs}2}={\stackrel{\·}{I}}_{\mathrm{bc}2}\\ {\stackrel{\·}{I}}_{\mathrm{fds}2}={\stackrel{\·}{I}}_{\mathrm{fd}2}\end{array}\right.---\left(13\right)$

After the overcompensation degree of arc suppression coil increases, the modulus value change of inductive currentThe change of the capacitance current modulus value of each bar non-fault line

$\left\{\begin{array}{c}{\mathrm{\ΔI}}_1=\left|{\stackrel{\·}{I}}_{12}\right|-\left|{\stackrel{\·}{I}}_{11}\right|\\ {\mathrm{\ΔI}}_2=\left|{\stackrel{\·}{I}}_{22}\right|-\left|{\stackrel{\·}{I}}_{21}\right|\\ {\mathrm{\ΔI}}_3=\left|{\stackrel{\·}{I}}_{32}\right|-\left|{\stackrel{\·}{I}}_{31}\right|\end{array}\right.---\left(14\right)$

On faulty line, the capacitive earth current modulus value change of each section of circuit is as follows respectively

$\left\{\begin{array}{c}{\mathrm{\ΔI}}_{\mathrm{ab}}=\left|{\stackrel{\·}{I}}_{\mathrm{ab}2}\right|-\left|{\stackrel{\·}{I}}_{\mathrm{ab}1}\right|\\ {\mathrm{\ΔI}}_{\mathrm{bc}}=\left|{\stackrel{\·}{I}}_{\mathrm{bc}2}\right|-\left|{\stackrel{\·}{I}}_{\mathrm{bc}1}\right|\\ {\mathrm{\ΔI}}_{\mathrm{bf}}=\left|{\stackrel{\·}{I}}_{\mathrm{bf}2}\right|-\left|{\stackrel{\·}{I}}_{\mathrm{bf}1}\right|\\ {\mathrm{\ΔI}}_{\mathrm{fd}}=\left|{\stackrel{\·}{I}}_{\mathrm{fd}2}\right|-\left|{\stackrel{\·}{I}}_{\mathrm{fd}1}\right|\end{array}\right.---\left(15\right)$ $\left\{\begin{array}{c}{\mathrm{\ΔI}}_{\mathrm{abs}}={\mathrm{\ΔI}}_L-({\mathrm{\ΔI}}_1+{\mathrm{\ΔI}}_2+{\mathrm{\ΔI}}_3)\\ {\mathrm{\ΔI}}_{\mathrm{abe}}={\mathrm{\ΔI}}_{\mathrm{abs}}-{\mathrm{\ΔI}}_{\mathrm{ab}}\\ {\mathrm{\ΔI}}_{\mathrm{bfs}}={\mathrm{\ΔI}}_{\mathrm{abe}}-{\mathrm{\ΔI}}_{\mathrm{bc}}\\ {\mathrm{\ΔI}}_{\mathrm{bfe}}={\mathrm{\ΔI}}_{\mathrm{bfs}}-{\mathrm{\ΔI}}_{\mathrm{bf}}\\ {\mathrm{\ΔI}}_{\mathrm{bcs}}={\mathrm{\ΔI}}_{\mathrm{bc}}\\ {\mathrm{\ΔI}}_{\mathrm{fds}}={\mathrm{\ΔI}}_{\mathrm{fd}}\end{array}\right.---\left(16\right)$

If breaking down as fault type is metallic earthing, before and after arc suppression coil parameter change, residual voltage is constant, and each line mutual-ground capacitor electric current is constant, i.e. Δ I₁、ΔI₂、ΔI₃、ΔI_ab、ΔI_bc、ΔI_bf、 ΔI_fdIt is all zero, the zero-sequence current variation delta I on failure path_abs、ΔI_abe、ΔI_bfs、ΔI_bfeEqual to arc suppression coil inductive current variation delta I_L, but not the zero-sequence current variation delta I on failure path_bcs、ΔI_fdsEqual to zero.Thus can draw the Sudden Changing Rate criterion under grounding requirement: when arc suppression coil reactance changes, if the zero-sequence current modulus value of this point alters a great deal, it is approximately equal to the change of arc suppression coil inductive current, then this test point is on failure path, if the zero-sequence current modulus value of this point is only small, it is approximately zero, illustrates that this point is on non-faulting path.

Earth fault judges that mechanism is as follows:

Substation PT residual voltage: have the voltage transformer of monitoring three-phase residual voltage in transformer station, once generation earth fault, the open delta voltage of voltage transformer will increase, when being increased above setting value, such transformer station has been considered as earth fault, now invention monitoring system sends: earth fault, and host computer will issue ground connection sample command, and in order native system, all monitoring points carry out fault sampling.

Earth fault is sampled: after data merging communication unit receives order, ABC three-phase collecting unit will be sent standard clock frequency (during satellite pair, time service), after completing, collecting unit starts to gather the current value (160 point) of transformer in the same moment, the data of these points is sent to data merging communication unit and carries out " Fourier " functional operation.Calculating amplitude and phase place, (for arc suppression coil system, this puts into sampling for first time), program proceeds.

Earthing type judges: before after system comes into operation or transforms, system comes into operation again, host computer can issue earthing type parameter, and this parameter is 1, and expression system is arc suppression coil system；Parameter is 2 to be expressed as isolated neutral system.This parameter is not unalterable, changes along with the whether use arc suppression coil of primary equipment of transformer station, and original system is isolated neutral system, but being likely to after Transfomer Substation Reconstruction is exactly arc suppression coil system；So program keeps such a flag bit, it is judged that the type of system, take different flow process and method.

The present invention can improve the judgement probability of small current neutral grounding system generation earth fault, and price is cheaply more a lot of than active injection method, and system interference is few.The present invention takes into account load monitoring function simultaneously, facilitates the load condition of information rack ceases to be busy.

The present invention is by earthing type in addition subregion, because different earthing types has distinctive earth fault feature itself, because of its feature selection diverse ways, thus can judge fault more accurately, improve breakdown judge probability.

The present invention adopts the current acquisition unit of A, B, C phase distinct program address, application collecting unit is divided into A, B, C phase acquisition indicating member, non-three-phase program address is consistent, make in the current information gathered not only with magnitude parameters, also with the parameter at phase angle, so be conducive to using the sudden change that the present invention uses mensuration, and vector method, breakdown judge is more accurate.

Claims (7)

1. the Earth design method based on zero sequence sudden change method and vector method, it is characterised in that comprise the steps:

In setting transformer station, PT residual voltage is than logarithm value USET；

Read PT residual voltage UO1 in transformer station；

Judge in transformer station PT residual voltage UO1 whether more than PT residual voltage than logarithm value USET；

In transformer station, PT residual voltage UO1 is more than PT residual voltage than logarithm value USET, sends out zero-sequence current sample command to each node, otherwise continues to read PT residual voltage UO1 in transformer station；

Obtain n node zero-sequence current numerical value IO1-IOn；

Judge whether zero-sequence current obtains complete；

Zero-sequence current obtains complete, it is judged that earthing type, otherwise continues to obtain node zero-sequence current numerical value；

Determine that earthing type is arc suppression coil；It is transmitted across compensating regulating command to arc suppression coil；

Again read off the residual voltage UO2 of system；

Again issue zero-sequence current sample command；

Obtain n node zero-sequence current IO1-IOn；

Suddenly change and mensuration calculate faulty line trouble point；Single-phase earthing alarm command is sent out along the line to fault；

Earthing type is non-arc suppression coil；Taking the maximum circuit of zero sequence is faulty line；

Zero sequence vector method orients trouble point；

Single-phase earthing alarm command is sent out along the line to fault.

2. the earth fault positioning device based on zero sequence sudden change method and vector method, it is characterised in that including:

For obtaining the built on stilts current acquisition unit of n node zero-sequence current numerical value IO1-IOn；

The data gathered being carried out waveform reduction, calculates the amplitude of average current value, calculate the initial phase angle of sampling every time, the data calculating synthesis zero-sequence current merge communication unit；

Than logarithm value USET, PT residual voltage UO1 in transformer station is read for setting PT residual voltage in transformer station；Adopt sudden change mensuration and zero sequence vector method calculates faulty line trouble point, the traversal identification according to trouble point in system Yu non-faulting point, it is judged that fault section, send out single-phase earthing alarm command the host computer shown over the display to fault along the line.

3. the earth fault positioning device of method and the vector method of suddenling change based on zero sequence according to claim 2, it is characterized in that: described data merge communication unit and include casing and case lid, described casing both sides are provided with fixing hanger, fixing hanger is provided with earhole, and two free ends of U-shaped snap ring are connected with earhole by nut；Described case lid is connected with casing by hinge axis；Being provided with solar panel on described case lid, described case lid surface configuration has support ear；It is provided with engaging lug bottom described solar panel；Support ear and engaging lug are provided with connecting hole；Described support ear and engaging lug distribution triangular in shape, upper support ear is connected with engaging lug；Supported underneath ear is connected with engaging lug by bracing frame.

4. the earth fault positioning device of method and the vector method of suddenling change based on zero sequence according to claim 2, it is characterised in that described data merge communication unit and include: for the 2.4G communicating circuit with built on stilts current acquisition unit communications；For the GPRS module with host computer device communication.

5. the earth fault positioning device of method and the vector method of suddenling change based on zero sequence according to claim 2, it is characterised in that: described built on stilts current acquisition unit includes solar panel, and solar panel is connected with power taking accumulator；Power taking accumulator is connected with Open Type Electric Current Mutual Inductor, current sampling circuit, low-power consumption monolithic processor, failure indicating circuit and 2.4G communicating circuit；Open Type Electric Current Mutual Inductor is connected with the preposition decision circuitry of short circuit, current sampling circuit；Low-power consumption monolithic processor is connected with the preposition decision circuitry of short circuit and current sampling circuit；Low-power consumption monolithic processor is connected with failure indicating circuit and 2.4G communicating circuit.

6. the earth fault positioning device of method and the vector method of suddenling change based on zero sequence according to claim 3, it is characterised in that: described data merge flush bonding processor, electric voltage observation circuit and the power supply operation indicating circuit that communication unit includes being arranged in casing.

7. the earth fault positioning device of method and the vector method of suddenling change based on zero sequence according to claim 3; it is characterized in that: described data merge communication unit and include charge management circuit, charge management circuit and solar panel and maintenance-free battery phase and discharge protection circuit are connected；Discharge protection circuit is connected with run switch and electric voltage observation circuit.