CN105866615A - 10kV power distribution line disconnection fault judging method based on three-phase voltage current - Google Patents

Abstract

The invention discloses a 10kV power distribution line disconnection fault judging method based on three-phase voltage current. The 10kV power distribution line disconnection fault judging method comprises the following steps: obtaining voltage and current information of each node of a power distribution network; determining a line with faults according to the acquired current information of the power distribution network, and judging whether the line with the faults has a line disconnection fault; judging the line disconnection fault to be a single-phase line disconnection fault or a multi-phase line disconnection fault; judging a specific fault type of the single-phase line disconnection fault or the multi-phase line disconnection fault; forwards or backwards comparing whether the voltage information of each node is consistent or not, and determining a specific fault section. The 10kV power distribution line disconnection fault judging method has the beneficial effects that judgment on single-phase line disconnection and a grounding complex fault thereof can be carried out by virtue of the acquired voltage current information, and accurate detecting and positioning can be carried out on multi-phase line disconnection and grounding complex faults thereof, so that fault handling time is shortened.

Description

10kV distribution line disconnection fault decision method based on three-phase voltage current

Technical field

The invention belongs to distribution line failure diagnostic techniques field, particularly to a kind of 10kV distribution wire based on three-phase voltage current Road disconnection fault decision method.

Background technology

In general power distribution network refers to 35kV and the electric power networks of following electric pressure thereof, effect be in city each power distribution station and All kinds of power loads are powered.China's major part city power distribution circuit uses 10kV electric pressure to customer power supply at present.Distribution Circuit distribution is wide, and total length is long, but running environment is severe, easily because thunderbolt, mechanical external force effect and line load are transshipped There is disconnection fault, the safety and reliability that serious threat is powered.After circuit generation disconnection fault, the quality of voltage of system will Can be affected by fairly obvious, the hree-phase symmetry of system is destroyed, simultaneously it is also possible to cause motor because of phase-deficient operation And burn, substantially reduce the service life of equipment.In addition also have the biggest may continue to after broken string and various earth fault occur, So may initiation fire, even electrocute people and animals, cause the consequence being difficult to save.

The negative-sequence current regularity of distribution in systems when prior art is by analyzing power distribution network generation single-phase wire break fault, must be out of order Rear system negative-sequence current major part is flowed to power supply by trouble point through faulty line, and the negative-sequence current of non-fault line is relatively small, In this, as the difference of minimax after the theoretical foundation of failure line selection, and faulted phase current absolute value difference in three-phase result In be maximum, can then take in half cycle the product of negative-sequence current and faulted phase voltage to the time with preliminary judgement fault phase Integrated value as energy norm, operating criterion be: estimate by the ceiling capacity avoiding other feeder line single-phase wire break faults carry out whole Fixed.

Prior art, for the radial topological feature of 10kV overhead transmission line, utilizes the fault component method negative phase-sequence to single-phase wire break fault Voltage's distribiuting is analyzed, it is proposed that single-phase wire break criterion based on negative sequence voltage amplitude.And combine load monitoring point to power supply point Minimal path analysis, it is proposed that single-phase wire break fault zone based on load monitor decision method, by delimit occur single-phase The Probability Area of disconnection fault and impossible region, make set difference operation by the two region simultaneously, draws minimum disconnection fault region.

Accident analysis and fault detect targeting scheme in above-mentioned technology have the disadvantage that

What the most above-mentioned document was both for is the treating method of single-phase wire break fault proposition, to additional ground fault, especially to many Phase disconnection fault lacks sufficiently to be analyzed, and solution is the most single, and is difficult to failure judgement type；

2. by detection negative-sequence current voltage as judgment basis, need to increase equipment in load side, add investment and equipment is transported The workload of dimension；

3. by comparing voltage current phase difference as judgment basis, under specific load type cases, erroneous judgement is easily caused, can It is difficult to ensure by property；

4. determine that abort situation is still difficult to accurately determine fault section by zoning, need indirect labor to patrol and determine specifically Trouble point.

Summary of the invention

The invention aims to overcome the problems referred to above, it is proposed that a kind of 10kV distribution line based on three-phase voltage current breaks Failure judgment method, the method relies solely on the information that can obtain on existing equipment, need not increase new equipment；Resolution principle Simply, reliability is high；Single-phase and heterogeneous broken string and ground connection complex fault thereof accurately can be judged.

For achieving the above object, the present invention uses following technical proposals:

10kV distribution line disconnection fault decision method based on three-phase voltage current, including:

(1) voltage of each node of power distribution network, current information are obtained；If certain measures point or certain several voltage x current measuring point becomes Change amplitude exceedes setting threshold value, then distribution line breaks down；

(2) determine, according to the power distribution network current information collected, the circuit broken down, and whether failure judgement circuit is broken string event Barrier, if it is, enter next step, otherwise, terminates；

(3) failure judgement type is single-phase wire break fault or heterogeneous disconnection fault；If single-phase wire break fault, enter step (4)；If heterogeneous disconnection fault, enter step (5)；

(4) according to the virtual value of each phase voltage of mains side bus after phase voltage virtual value, fault before fault and voltage setting valve it Between relation, it is determined that the concrete fault type of single-phase wire break fault；Enter step (6)；

(5) according to the virtual value of each phase voltage of mains side bus, fault afterload side phase after phase voltage virtual value, fault before fault Relation between voltage-to-ground and voltage setting valve, it is determined that the concrete fault type of heterogeneous disconnection fault；Enter step (6)；

(6) the most consistent by comparing each node voltage information forward or backward, determine concrete fault section.

Further, in described step (2), if distribution line three-phase current occurs phase current disappearance or a three-phase current All reduce, then this distribution line is defined as faulty line；

When there is the absolute value of at least one phase current less than current calibration threshold value in faulty line, it is determined that faulty line is disconnection fault.

Further, in described step (3),

If meet following condition simultaneously, then it is judged as single-phase wire break fault:

1) wherein the absolute value of the current effective value of a phase is not more than current calibration threshold value；

2) absolute value of the most biphase current effective value is equal, and its value betweenBetween, I_NBefore fault Phase current virtual value；

3) difference of the most biphase current phase angle is between [120 °, 180 °]；

If the virtual value of faulty line three-phase current is equal, and absolute value is no more than current calibration threshold value, then be judged to send out Raw heterogeneous disconnection fault.

Further, in described step (4), the decision method of the concrete fault type of single-phase wire break fault is:

1) judging whether the phase that voltage is zero occur, if it is not, be judged to the unsettled fault in single-phase wire break two ends, voltage raises A phase be judged to disconnection fault phase；If it has, be then attended by earth fault, proceed to next step；

2) judge power supply be zero at mains side still in load side, if at mains side, be then judged to that single-phase wire break powers up Side joint earth fault, voltage be zero be judged to disconnection fault phase mutually；If in load side, then it is judged to single-phase wire break application of load side Earth fault, voltage be zero be judged to disconnection fault phase mutually.

Further, in described step (5), the concrete fault type of heterogeneous disconnection fault includes: biphase broken string phase to phase fault, Biphase broken string powers up source one phase earth fault, biphase broken string application of load side one phase earth fault, three-phase disconnection fault.

Further, in described step (5),

If faulty line three-phase current is satisfied by less than current calibration threshold value, and occur that a phase voltage is down to 0, then judgement is No it is down to 0 for load side voltage:

If load side voltage is down to 0, then can determine that as there is biphase broken string application of load side one phase earth fault, mains side voltage Non-zero biphase for fault phase；

If load side voltage is not 0, be then judged to occur biphase broken string to power up source one phase earth fault, mains side voltage with Different biphase for fault phase of load side voltage.

Further, in described step (5),

If faulty line three-phase current is satisfied by less than current calibration threshold value, and do not occur that a phase voltage is 0；Then judge electricity Whether source phase voltage changes, if changed, is then judged to that biphase broken string phase to phase fault, two voltages raise mutually for broken string Fault phase.

Further, in described step (5),

If each phase voltage of load side is down to 0, mains side voltage keeps constant, then be judged to three-phase disconnection fault.

Further, it is determined that the method for concrete fault section is:

If mains side change in voltage is beyond setting threshold value, then starts the point of trouble-shooting backward from mains side node, first compare mains side First node voltage after node and second node voltage, if both are consistent, then compare second after mains side node joint Point voltage and the 3rd node voltage, until finding inconsistent two nodes of node voltage information, it is determined that trouble point is positioned at this Between two nodes；

If the change of mains side busbar voltage is not above setting threshold value, then fault afterload side change in voltage will exceed setting threshold value, Now start the point of trouble-shooting forward from load side, find two nodes that adjacent node information of voltage is inconsistent, it is determined that fault Point is between the two node.

The invention has the beneficial effects as follows:

1. the principle of the invention is simple, it is achieved easily；It is not required to additionally increase equipment, low cost, does not increase maintenance work amount；

2., by the voltage x current information collected, it is possible not only to carry out single-phase wire break and the judgement of ground connection complex fault thereof, moreover it is possible to Enough heterogeneous broken string and ground connection complex fault thereof accurately detected and position, shortening the time of troubleshooting.

Accompanying drawing explanation

Fig. 1 is distribution network equivalent structure figure；

Fig. 2 is distribution line monitoring device structure chart of the present invention；

Fig. 3 is the system construction drawing that the present invention carries out disconnection fault detection and location；

Fig. 4 is fault verification main flow chart of the present invention；

Fig. 5 is single-phase wire break fault verification flow chart of the present invention；

Fig. 6 is the present invention heterogeneous disconnection fault decision flowchart.

Detailed description of the invention:

The present invention will be further described with example below in conjunction with the accompanying drawings:

Power distribution network simplified structure diagram as shown in Figure 1,18 nodes are this monitoring device mount point, its interior joint 2,3 node Between there occurs that disconnection fault, circuit I are faulty line, circuit II represents the substitutional connection of other non-fault lines.

Flow process as shown in Figure 4, the present embodiment carries out detection and the location of 10kV disconnection fault by following steps:

The first step, obtains the voltage of each node, current information by the monitoring device being arranged on each node of distribution line.

Described power distribution network refer to by overhead transmission line, cable, shaft tower, distribution transformer, disconnecting switch, reactive-load compensation equipment with And the radial pattern electric power networks of the 10kV electric pressure of other affiliated facilities composition.

Described monitoring device has structure as shown in Figure 2, and the analog quantity such as voltage, electric current passes through voltage transformer secondary side, electricity Current transformer secondary side input equipment, data collecting system includes that voltage formation, simulation low-pass filter (LPF), sampling keep The functional devices such as device (S/H) and digital-to-analogue conversion (A/D), complete that simulation input quantity is converted to micro computer exactly and are capable of identify that Digital quantity；Digital signal is analyzed by Digital Signal Processing (DSP) chip, obtains the amplitude phase place of gathered voltage x current； The voltage x current information obtained is compared by host CPU with the failure criterion in storage facilities, it may be judged whether broken string event occurs Barrier and fault type；Communication interface connects host CPU and communication network, uploads each survey by communication interface host CPU to master control system The fault message of amount point, master control system assigns action command to host CPU；The xegregating units such as exit relay connection line disconnecting link, Action under host CPU order；Human-computer interaction device's interface connects the display devices such as liquid crystal display, alarm window, alarm lamp, to Staff reports fault message.

Described voltage, current information are referred to each node each phase-to-ground voltage amplitude and phase place, each phase current magnitude and phase place.

Second step: when detecting that certain measures point or certain several voltage x current amplitude of variation measuring point exceedes setting threshold value, first root According to the current information failure judgement circuit collected, determine short trouble or disconnection fault, determine it is single-phase wire break event simultaneously Barrier or heterogeneous disconnection fault.

(1) faulty line screening:

Occur that the circuit broken there will be a phase current disappearance or three-phase current is all greatly lowered, and non-fault line three-phase Electric current is normal.

(2) short trouble and the differentiation of disconnection fault:

With current value as criterion, when at least one phase current occurs | I_f| ＜ I_set, wherein I_fFor faulted phase current, I_setFor current calibration Threshold value, should adjust by the maximum current that fault phase when occurring disconnection fault in system is likely to occur, and electric current meets above formula and then may be used It is judged that there is disconnection fault.I.e. when at least one phase current occurring less than setting valve, it is possible to judge to there occurs disconnection fault, And the fault that is short-circuited in isolated neutral system does not haves the situation that electric current is greatly lowered.

(3) single-phase wire break fault or heterogeneous disconnection fault are judged:

If meet following condition simultaneously, then it is judged as single-phase wire break fault:

1) wherein the absolute value of the current effective value of a phase is not more than current calibration threshold value；

2) absolute value of the most biphase current effective value is equal, and its value betweenBetween, I_NBefore fault Phase current virtual value；

3) difference of the most biphase current phase angle is between [120 °, 180 °]；

WhereinFor three-phase current, I_setFor current calibration threshold value, should can by fault phase when disconnection fault occurs in system The maximum current that can occur is adjusted, I_LFor fault preload current effective value.When three-phase current meets above-mentioned condition, permissible It is judged to there occurs A phase disconnection fault.

Heterogeneous disconnection fault electric current criterion:

$\left|{\stackrel{\·}{I}}_A\right|=\left|{\stackrel{\·}{I}}_B\right|=\left|{\stackrel{\·}{I}}_C\right|\≤I_{set};$

I_setFor current calibration threshold value, should adjust by the maximum current that fault phase when occurring disconnection fault in system is likely to occur, The heterogeneous disconnection fault of generation is can be determined that when electric current meets above-mentioned condition.

3rd step: according to the result of second step gained, respectively enters single-phase wire break fault verification flow process or heterogeneous disconnection fault is sentenced Constant current journey, determines concrete fault type.

Concrete fault type includes:

The unsettled fault in single-phase wire break two ends, single-phase wire break power up side joint earth fault, single-phase wire break application of load side joint earth fault；

The unsettled fault in biphase broken string two ends, biphase broken string power up source one phase earth fault, biphase broken string application of load side one phase ground connection Fault.

As it is shown in figure 5, single-phase wire break determination flow specifically includes:

1) judging whether the phase that voltage is zero occur, if it is not, be judged to the unsettled fault in single-phase wire break two ends, voltage raises A phase be judged to disconnection fault phase；If it has, be then attended by earth fault, proceed to next step；

The assistant criteria of the unsettled fault of single-phase wire break and two ends is:

$\left\{\begin{array}{c}{E}_M+\mathrm{\Δ}E\≤\left|\stackrel{.}{U_{AM}}\right|\≤1.5E_M-\mathrm{\Δ}E\\ \frac{\sqrt{3}}{2}{E}_M+\mathrm{\Δ}E\≤\left|\stackrel{.}{U_{BM}}\right|=\left|\stackrel{.}{U_{CM}}\right|\≤E_M-\mathrm{\Δ}E\end{array}\right.;$

In above formulaIt is respectively each phase-to-ground voltage of mains side bus after fault, E_MFor phase before mains side bus-bar fault Voltage effective value, Δ E is allowable error value of adjusting, and should be the maximum deflection difference value of phase voltage when there is this fault in system.

2) judge power supply be zero at mains side still in load side, if at mains side, be then judged to that single-phase wire break powers up Side joint earth fault, voltage be zero be judged to disconnection fault phase mutually；If in load side, then it is judged to single-phase wire break application of load side Earth fault, voltage be zero be judged to disconnection fault phase mutually.

Single-phase wire break and mains side earth fault assistant criteria be:

$\left\{\begin{array}{c}\left|\stackrel{.}{U_{AM}}\right|\≤U_{set}\\ \sqrt{3}{E}_M-\mathrm{\Δ}E\≤\left|\stackrel{.}{U_{BM}}\right|=\left|\stackrel{.}{U_{CM}}\right|\≤\sqrt{3}{E}_M+\mathrm{\Δ}E\end{array}\right.;$

In above formula, U_setFor voltage setting valve, should adjust by the maximum voltage that fault phase when there is this fault in system is likely to occur. Single-phase wire break and load side earth fault assistant criteria be:

$\left\{\begin{array}{c}\left|U_{AN}\right|\≤U_{set}\\ 1.5E_M-\mathrm{\Δ}E\≤\left|U_{AM}\right|\≤1.5E_M+\mathrm{\Δ}E\\ \frac{\sqrt{3}}{2}{E}_M-\mathrm{\Δ}E\≤\left|U_{BM}\right|=\left|U_{CM}\right|\≤\frac{\sqrt{3}}{2}{E}_M+\mathrm{\Δ}E\end{array}\right.;$

U_ANFor fault afterload side A phase-to-ground voltage virtual value, Δ E is allowable error value of adjusting, and should be and this event occurs in system The maximum deflection difference value of phase voltage during barrier.

Heterogeneous disconnection fault determination flow as shown in Figure 6, specifically includes:

Biphase broken string and mains side line to line fault and biphase broken string and the mains side line to line fault same two-phase short-circuit fault of earth fault feature, Phase fault electric current occur, carry out protection seting according to current protection principle, now action is tripped by current protecting equipment.

Without there is phase fault electric current, then three-phase current is not more than current calibration threshold value, it may be judged whether a phase electricity occur Pressure drop is to 0；

If 1 faulty line three-phase current is satisfied by current calibration threshold value, and occurs that a phase voltage is down to 0, then judge whether It is down to 0 for load side voltage:

If load side voltage is down to 0, then can determine that as there is biphase broken string application of load side one phase earth fault, mains side voltage Non-zero two phase place fault phase.

Biphase broken string application of load side one phase earth fault assistant criteria is:

$\left\{\begin{array}{c}\left|\stackrel{.}{U_{AM}}\right|=\left|\stackrel{.}{U_N}\right|\≤U_{set}\\ \sqrt{3}{E}_M-\mathrm{\Δ}E\≤\left|\stackrel{.}{U_{BM}}\right|=\left|\stackrel{.}{U_{CM}}\right|\≤\sqrt{3}{E}_M+\mathrm{\Δ}E\end{array}\right.;$

For load side phase voltage virtual value, because three coincide, so representing with a symbol.According toCan With determine fault phase as B, C biphase, by A phase voltage minimum understand be load side ground connection.

If load side voltage is not 0, mains side one phase voltage is down to 0, then be judged to that occurring biphase broken string to power up source one connects Earth fault, biphase for fault phase different with load side voltage of mains side voltage.

Biphase broken string powers up source one phase earth fault assistant criteria for (as a example by B phase ground connection):

$\left\{\begin{array}{c}\left|\stackrel{.}{U_{BM}}\right|\≤U_{set}\\ \sqrt{3}{E}_M-\mathrm{\Δ}E\≤\left|\stackrel{.}{U_{AM}}\right|=\left|\stackrel{.}{U_{CM}}\right|=\left|\stackrel{.}{U_N}\right|\≤\sqrt{3}{E}_M+\mathrm{\Δ}E\end{array}\right.;$

U_setFor voltage setting valve；Δ E is allowable error value of adjusting, and setting principle is ibid；The most electric for fault afterload side Pressure, because three coincide, so representing with a symbol.

If 2 faulty line three-phase currents are satisfied by current calibration threshold value, do not occur that a phase voltage is 0；Then it is judged to biphase Broken string phase to phase fault, it is disconnection fault phase mutually that two voltages raise.

Biphase broken string phase to phase fault assistant criteria is:

$\left\{\begin{array}{c}0\≤\left|\stackrel{.}{U_{AM}}\right|\≤E_M\\ E_M\≤\left|\stackrel{.}{U_{BM}}\right|=\left|\stackrel{.}{U_{CM}}\right|\≤\sqrt{3}{E}_M\end{array}\right.;$

The respectively virtual value of each phase voltage of mains side bus, E after fault_MFor phase voltage virtual value before fault.

3, three-phase disconnection fault is equivalent to cutting load, and fault signature is obvious, and each phase voltage of load side is down to 0, mains side electricity Pressure keeps constant.

Described mains side is the side being positioned at upstream, trouble point near feeder ear.Described load side is that downstream, trouble point is near by electricity End side.

4th step: the most consistent by comparing each node voltage information forward or backward, determines concrete fault section.

The described detailed process comparing each node voltage information forward or backward is described as follows:

As shown in Fig. 3 system diagram, monitoring device is arranged on distribution line and respectively measures a little, and each device is connected to by communication network In master control system, monitoring device collection and upload each measure point electric quantity information, master control system is to these information and fault data Information comparison in storehouse, determines fault type, and determines fault section by relatively more each voltage measuring point.Comparison procedure is such as Under: if as it is shown in figure 1, fault occurs between 2, the 3 of circuit I, measure and electric current phase shortage detected at point 1, and measure Point 5 each phase currents are normal, it is possible to determine that circuit I there occurs disconnection fault, in order to determine fault section, if mains side voltage becomes Change beyond setting threshold value, then start the point of trouble-shooting backward from mains side node, first compare measurement point 1 and measure point 2 voltages, Two measure point voltage information unanimously, compare measurement point 2 the most again and measure 3 voltage, and now the information of voltage of 2,3 is inconsistent, Then may determine that fault is put between 2,3 in measurement, and combine above fault assistant criteria, it may be determined that fault is separate and former Barrier type.If mains side measures point voltage, change is inconspicuous, then fault afterload side change in voltage will be beyond setting threshold value, this Time can from load side measure point start the point of trouble-shooting forward, as from measure point 4 start addressing, first compare measurement point 4 and survey Information of voltage between amount point 3, two measure point voltage information unanimously, then compare the information of voltage measured point 3 and measure between point 2, Now two measurement point voltage information are inconsistent, then may determine that fault is being measured between point 3,2.

Although the detailed description of the invention of the present invention is described by the above-mentioned accompanying drawing that combines, but not limit to scope System, one of ordinary skill in the art should be understood that on the basis of technical scheme, and those skilled in the art need not pay Go out various amendments or deformation that creative work can make still within protection scope of the present invention.

Claims (9)

1. 10kV distribution line disconnection fault decision method based on three-phase voltage current, is characterized in that, including:

(1) voltage of each node of power distribution network, current information are obtained；If certain measures point or certain several voltage x current measuring point becomes Change amplitude exceedes setting threshold value, then distribution line breaks down；

(2) determine, according to the power distribution network current information collected, the circuit broken down, and whether failure judgement circuit is broken string event Barrier, if it is, enter next step, otherwise, terminates；

(3) failure judgement type is single-phase wire break fault or heterogeneous disconnection fault；If single-phase wire break fault, enter step (4)；If heterogeneous disconnection fault, enter step (5)；

(4) according to the virtual value of each phase voltage of mains side bus after phase voltage virtual value, fault before fault and voltage setting valve it Between relation, it is determined that the concrete fault type of single-phase wire break fault；Enter step (6)；

(5) according to the virtual value of each phase voltage of mains side bus, fault afterload side phase after phase voltage virtual value, fault before fault Relation between voltage-to-ground and voltage setting valve, it is determined that the concrete fault type of heterogeneous disconnection fault；Enter step (6)；

(6) the most consistent by comparing each node voltage information forward or backward, determine concrete fault section.

A kind of 10kV distribution line disconnection fault decision method based on three-phase voltage current, its Feature is, in described step (2), if occurring in distribution line three-phase current that a phase current disappearance or three-phase current all drop Low, then this distribution line is defined as faulty line；

When there is the absolute value of at least one phase current less than current calibration threshold value in faulty line, it is determined that faulty line is disconnection fault.

A kind of 10kV distribution line disconnection fault decision method based on three-phase voltage current, its Feature is, in described step (3),

If meet following condition simultaneously, then it is judged as single-phase wire break fault:

1) wherein the absolute value of the current effective value of a phase is not more than current calibration threshold value；

2) absolute value of the most biphase current effective value is equal, and its value betweenBetween, I_NBefore fault Phase current virtual value；

3) difference of the most biphase current phase angle is between [120 °, 180 °]；

If the virtual value of faulty line three-phase current is equal, and absolute value is no more than current calibration threshold value, then be judged to send out Raw heterogeneous disconnection fault.

A kind of 10kV distribution line disconnection fault decision method based on three-phase voltage current, its Feature is, in described step (4), the decision method of the concrete fault type of single-phase wire break fault is:

1) judging whether the phase that voltage is zero occur, if it is not, be judged to the unsettled fault in single-phase wire break two ends, voltage raises A phase be judged to disconnection fault phase；If it has, be then attended by earth fault, proceed to next step；

2) judge power supply be zero at mains side still in load side, if at mains side, be then judged to that single-phase wire break powers up Side joint earth fault, voltage be zero be judged to disconnection fault phase mutually；If in load side, then it is judged to single-phase wire break application of load side Earth fault, voltage be zero be judged to disconnection fault phase mutually.

A kind of 10kV distribution line disconnection fault decision method based on three-phase voltage current, its Feature is, in described step (5), the concrete fault type of heterogeneous disconnection fault includes: biphase broken string phase to phase fault, biphase Broken string powers up source one phase earth fault, biphase broken string application of load side one phase earth fault, three-phase disconnection fault.

A kind of 10kV distribution line disconnection fault decision method based on three-phase voltage current, its Feature is, in described step (5),

If faulty line three-phase current is satisfied by less than current calibration threshold value, and occur that a phase voltage is down to 0, then judgement is No it is down to 0 for load side voltage:

If load side voltage is down to 0, then can determine that as there is biphase broken string application of load side one phase earth fault, mains side voltage Non-zero biphase for fault phase；

If load side voltage is not 0, be then judged to occur biphase broken string to power up source one phase earth fault, mains side voltage with Different biphase for fault phase of load side voltage.

A kind of 10kV distribution line disconnection fault decision method based on three-phase voltage current, its Feature is, in described step (5),

If faulty line three-phase current is satisfied by less than current calibration threshold value, and do not occur that a phase voltage is 0；Then judge electricity Whether source phase voltage changes, if changed, is then judged to that biphase broken string phase to phase fault, two voltages raise mutually for broken string Fault phase.

A kind of 10kV distribution line disconnection fault decision method based on three-phase voltage current, its Feature is, in described step (5),

If each phase voltage of load side is down to 0, mains side voltage keeps constant, then be judged to three-phase disconnection fault.

A kind of 10kV distribution line disconnection fault decision method based on three-phase voltage current, its Feature is, in described step (6), determines that the method for concrete fault section is:

If mains side change in voltage is beyond setting threshold value, then starts the point of trouble-shooting backward from mains side node, first compare mains side First node voltage after node and second node voltage, if both are consistent, then compare second after mains side node joint Point voltage and the 3rd node voltage, until finding inconsistent two nodes of node voltage information, it is determined that trouble point is positioned at this Between two nodes；

If the change of mains side busbar voltage is not above setting threshold value, then fault afterload side change in voltage will exceed setting threshold value, Now start the point of trouble-shooting forward from load side, find two nodes that adjacent node information of voltage is inconsistent, it is determined that fault Point is between the two node.