CN105870891A - Fault detection and isolation method applicable to multi-branch low-voltage direct-current power distribution system - Google Patents
Fault detection and isolation method applicable to multi-branch low-voltage direct-current power distribution system Download PDFInfo
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- CN105870891A CN105870891A CN201610259570.1A CN201610259570A CN105870891A CN 105870891 A CN105870891 A CN 105870891A CN 201610259570 A CN201610259570 A CN 201610259570A CN 105870891 A CN105870891 A CN 105870891A
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- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02H—EMERGENCY PROTECTIVE CIRCUIT ARRANGEMENTS
- H02H7/00—Emergency protective circuit arrangements specially adapted for specific types of electric machines or apparatus or for sectionalised protection of cable or line systems, and effecting automatic switching in the event of an undesired change from normal working conditions
- H02H7/26—Sectionalised protection of cable or line systems, e.g. for disconnecting a section on which a short-circuit, earth fault, or arc discharge has occured
- H02H7/268—Sectionalised protection of cable or line systems, e.g. for disconnecting a section on which a short-circuit, earth fault, or arc discharge has occured for dc systems
-
- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02H—EMERGENCY PROTECTIVE CIRCUIT ARRANGEMENTS
- H02H7/00—Emergency protective circuit arrangements specially adapted for specific types of electric machines or apparatus or for sectionalised protection of cable or line systems, and effecting automatic switching in the event of an undesired change from normal working conditions
- H02H7/26—Sectionalised protection of cable or line systems, e.g. for disconnecting a section on which a short-circuit, earth fault, or arc discharge has occured
- H02H7/261—Sectionalised protection of cable or line systems, e.g. for disconnecting a section on which a short-circuit, earth fault, or arc discharge has occured involving signal transmission between at least two stations
- H02H7/262—Sectionalised protection of cable or line systems, e.g. for disconnecting a section on which a short-circuit, earth fault, or arc discharge has occured involving signal transmission between at least two stations involving transmissions of switching or blocking orders
-
- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02H—EMERGENCY PROTECTIVE CIRCUIT ARRANGEMENTS
- H02H7/00—Emergency protective circuit arrangements specially adapted for specific types of electric machines or apparatus or for sectionalised protection of cable or line systems, and effecting automatic switching in the event of an undesired change from normal working conditions
- H02H7/26—Sectionalised protection of cable or line systems, e.g. for disconnecting a section on which a short-circuit, earth fault, or arc discharge has occured
- H02H7/261—Sectionalised protection of cable or line systems, e.g. for disconnecting a section on which a short-circuit, earth fault, or arc discharge has occured involving signal transmission between at least two stations
- H02H7/263—Sectionalised protection of cable or line systems, e.g. for disconnecting a section on which a short-circuit, earth fault, or arc discharge has occured involving signal transmission between at least two stations involving transmissions of measured values
-
- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02H—EMERGENCY PROTECTIVE CIRCUIT ARRANGEMENTS
- H02H7/00—Emergency protective circuit arrangements specially adapted for specific types of electric machines or apparatus or for sectionalised protection of cable or line systems, and effecting automatic switching in the event of an undesired change from normal working conditions
- H02H7/26—Sectionalised protection of cable or line systems, e.g. for disconnecting a section on which a short-circuit, earth fault, or arc discharge has occured
- H02H7/267—Sectionalised protection of cable or line systems, e.g. for disconnecting a section on which a short-circuit, earth fault, or arc discharge has occured for parallel lines and wires
Abstract
The invention discloses a fault detection and isolation method applicable to a multi-branch low-voltage direct-current power distribution system, and belongs to the safety detection technical field of a direct-current power distribution system. According to the method, single-branch sub modules are flexibly configured according to nodes and branches of the direct-current system; the multi-branch low-voltage direct-current power distribution system protection is formed comprehensively; fault recognition is realized by detecting the inductive current and the capacitor voltage characteristics in each branch sub module; and fault isolation is carried out by controllable electronic switches in the branch sub modules. According to the method, a direct-current circuit breaker is not required, so that the cost is relatively low; the fault detection and isolation method is applicable to the multi-branch and single-loop, single-pole and dual-pole direct-current power distribution system; the fault detection and isolation method is simple in method, high in protection action speed, and relatively high in transitional resistance tolerance; and meanwhile, only the fault branches are isolated, so that the power failure range is not enlarged.
Description
Technical field
The invention belongs to the safety detection technology field of direct-flow distribution system, be applicable to multiple-limb low pressure particularly to one
The fault detect of direct-flow distribution system and partition method.
Background technology
Along with Power Electronic Technique and the development that controls technology, high voltage dc transmission technology due to its good controllability and
Economy and be applied to remote, large capacity transmission more and more widely.In the field of distribution network of mesolow grade, direct current supply
System also result in extensively attention, and is applied to industrial park, track traffic tractive power supply system, aircraft and naval vessel electric power system
Deng.Than alternating-current system, DC distribution technology has the advantage that 1) DC distribution net can save track investment, also
Have that the quality of power supply is high, transmission capacity is big, system architecture is simple, good economy performance and the advantage such as electric energy loss is low.2) direct current is used
Power distribution network, can reduce one-level power conversion when distributed power source and DC load access and straight-flow system does not collect skin effect
Should, there is relatively low reactive power loss, thus improve the power supplying efficiency of distribution system；3) need of intelligent distribution network development are adapted to
, flexible direct current power distribution network can realize the flexible control of power, and user, sale of electricity business and power grid enterprises all can benefit from its operation
Controllability and flexibility.But, the application of direct-flow distribution system still suffers from many problems.Wherein, relay protection relation
Safety and reliability to DC distribution network operation.Owing to the equipment of flexible direct current distribution system is more, the method for operation is changeable,
Fault characteristic is affected by factors such as system topological, fault type and the positions of fault and is presented the polymorphic feature of complexity, gives protection system
Design and the cooperation of system bring the biggest difficulty.Especially in multiple-limb distribution system, due to relevant fault detection method also
The most ripe, the problem such as the technology of dc circuit breaker and deployment cost in addition, DC distribution protection system still lacks relevant mark
Standard and operating experience, there is presently no Protection Technology the most ripe, that cost performance is higher and equipment tackles DC distribution system
The various faults of system.
Summary of the invention
It is an object of the invention to provide a kind of fault detect being applicable to multiple-limb low-voltage direct distribution system and isolation side
Method, it is characterised in that described multiple-limb low-voltage direct distribution system is a multinode direct-flow distribution system, deposits at each node
In multiple branches；How many branches, then single branch submodule of corresponding configuration equal number is had at this node；And at each node
Place configures the protection of a set of multiple-limb low-voltage direct distribution system；Input the first inductance L1 of single branch submodule, the second inductance
L2 connects a branch of two nodes, the multiple-limb low-voltage direct at the output of single branch submodule and other node respectively
Distribution system protection connects；
Consist of the first inductance L1, the first electronic switch ES1, the 3rd inductance L3 and the electric current of described single branch submodule pass
Sensor CS connects, and one end of the second electronic switch ES2 and the common junction of the first electronic switch ES1 and the 3rd inductance L3 connect,
The other end of the second electronic switch ES2 and the second inductance L2 connect；Upper end after electric capacity C1, voltage sensor VS parallel connection and electric current
Sensor CS connects, and lower end and electronic switch ES2's and the second inductance L2's common junction is connected；The group of Ge Dan branch submodule
Become identical；Wherein, the current detecting utilize electric capacity C1 both end voltage, flowing through inductance L3 is protected branch the most faulty, voltage
Sensor VS is for detecting the voltage u at electric capacity C1 two endsC；Current sensor CS flows through the electric current i of inductance L3 for detectionL；First
Inductance L1 and the second inductance L2, constitutes filter unit with electric capacity C1 time system is normal, when being broken down by protection branch road,
Avoid causing the acute variation of adjacent legs electric parameters to impact to the properly functioning and Fault Identification of other branch；3rd
Inductance L3, flows through utilization the current detecting of this inductance and is protected branch's whether fault, by protection branch properly functioning time, it is not
Direct-flow distribution system can be impacted.
Described first electronic switch ES1 and the second electronic switch ES2 is two-way gate-controlled switch device；All use MOSFET,
IGBT or GTO, chooses the power capacity of above-mentioned gate-controlled switch device according to concrete application scenario；When properly functioning by protection branch road
When, the first electronic switch ES1 Guan Bi, the second electronic switch ES2 disconnect；When this branch trouble being detected, by multiple-limb
Low-voltage direct distribution system protection control the first electronic switch ES1 opens, the second electronic switch ES2 Guan Bi.
The described fault detect being applicable to multiple-limb low-voltage direct distribution system and partition method, it is characterised in that same
Current sensor in the protection of multiple-limb low-voltage direct distribution system and the electric current that obtains of voltage sensor measurement and information of voltage
All send the protection of this multiple-limb low-voltage direct distribution system to carry out unifying computing, it is achieved fault detect and isolation, including such as
Lower step:
1), when being run by protection multiple-limb low-voltage direct distribution system, Ge Dan branch submodule is surveyed by current sensor CS
Amount flows through the inductive current i of the 3rd inductance L3L, the capacitance voltage u at electric capacity C1 two ends is measured by voltage sensor VSC；
2) calculated, by the protection of multiple-limb low-voltage direct distribution system, the electricity that its Ge Dan branch submodule comprised collects
The absolute value of inducing current rate of change | diL/ dt | and capacitance voltage rate of change duC/ dt, and with the absolute value of inductive current rate of change |
diL/ dt | or capacitance voltage rate of change duC/ dt detects as failure criterion
No breaking down, any of which criterion meets and i.e. thinks that respective branches DC line/cable exists fault；
3) for there is the branch of fault, the protection of multiple-limb low-voltage direct distribution system the first electronic switch ES1 is controlled
Disconnect, the second electronic switch ES2 closes；The multiple-limb low-voltage direct distribution system protection of fault branch both sides in like manner detects fault
And control electronic switch, it is achieved the isolation of fault branch.Properly functioning branch road will not be isolated, and is prevented effectively from expansion power failure model
Enclose；
4) protection of multiple-limb low-voltage direct distribution system sends and controls the first electronic switch ES1 disconnection, the second electronic switch
After the order of ES2 Guan Bi, continue detection and flow through the electric current of inductance in single branch submodule, if this electric current is continuously less than k4in, then
Think that the first electronic switch ES1 in this branch's submodule disconnects；If this electric current is more than k4inAnd the duration reaches Tset2In the least
Second, then controlled the first electronic switch in other all branches submodule of this node by the protection of multiple-limb low-voltage direct distribution system
ES1 disconnects, the second electronic switch ES2 Guan Bi；Wherein, k4For the safety factor less than 1, more than 0, inProperly functioning for this branch
Electric current.
Described failure criterion includes:
Failure criterion 1: if the absolute value of inductive current rate of change that certain single branch submodule records | diL/ dt | more than setting
The threshold value Δ i putth, and capacitance voltage rate of change duC/ dt is less than the threshold value Δ u arrangedth, then this list branch submodule is judged
There is fault in the direct current branch that block is protected；I.e. criterion is 1 to be: | diL/dt|>ΔithAnd duC/dt<Δuth, wherein, Δ ith=
k1Δimax, Δ uth=k2Δumin。k1And k2Be greater than 1 respectively, safety factor less than 2 with less than-1, more than-2, it is contemplated that
Using bicharacteristic amount to judge, the two coefficient can the most suitably take close to 1 and-1；ΔimaxIt is: 1) system normal course of operation
In, 2) other single branch submodule is protected in the protection of same multiple-limb low-voltage direct distribution system DC line/cable goes out
Fault at Kou, 3) single branch submodule of being adjusted corresponding by protection DC line/cable end piece fault time, adjusted point
The maximum of the inductive current rate of change absolute value in submodule；ΔuminIt is: 1) in system normal course of operation, 2) same
Fault at DC line/cable outlet that in the protection of multiple-limb low-voltage direct distribution system, other single branch submodule is protected,
3) single branch submodule of being adjusted corresponding by protection DC line/cable end piece fault time, the single branch submodule adjusted
The minimum of a value of capacitance voltage rate of change in block；
Failure criterion 2: if certain single branch submodule is at Tset3The capacitance voltage u recorded continuously in Hao MiaoCIt is below setting
Low-voltage threshold value uth, illustrate that the branch road that this certain branch's submodule is protected exists fault；Low-voltage threshold value uthCalculating:
uth=k3un, wherein, k3Be less than 1, safety factor more than 0, unIt it is multiple-limb low-voltage direct distribution system rated voltage；Single
In branch's submodule, the second electronic switch ES2 disconnects, the first electronic switch ES1 closes, during restoring electricity, and this criterion of locking
Tset1Millisecond；
Failure criterion 3: if the information of the multiple-limb low-voltage direct distribution system protection of certain branch's both sides configuration can be obtained,
Any one during then the Liang Gedan branch submodule for same DC line/cable both sides meets following 3 conditions, the most satisfied
A) both sides inductive current rate of change absolute value is all higher than set threshold value；B) capacitance voltage rate of change in both sides is respectively less than set
The threshold value put；C) side inductive current rate of change absolute value is more than set threshold value and opposite side capacitance voltage rate of change
Less than set threshold value, then judge that this branch exists fault；Each threshold value setting method is with failure criterion 1 and failure criterion
2。
The invention has the beneficial effects as follows that this method need not configuring direct current breaker, cost is relatively low；Be applicable to multiple-limb and
Single loop, one pole and bipolar DC distribution system；Fault detect and partition method are simple, protection act speed is fast, possess stronger
Tolerance transition resistance ability, only isolate fault branch, power failure range will not be expanded
Accompanying drawing explanation
Fig. 1 is that multiple-limb low-voltage direct distribution system protects structural representation.
Fig. 2 is fault detect and isolation FB(flow block).
Fig. 3 is the multiple-limb low-voltage direct distribution system protection schematic diagram containing 3 Ge Dan branch submodules.
Inductive current that when Fig. 4 is Fault point failure, DCswitch2 records and capacitance voltage change curve, wherein a is
Inductive current；B is capacitance voltage.
Fig. 5. inductive current that non-faulting branch road list branch submodule DCswitch1 records and capacitance voltage change curve
Figure, wherein a is inductive current；B is capacitance voltage.
Fig. 6. inductive current that non-faulting branch road list branch submodule DCswitch3 records and capacitance voltage change curve
Figure, wherein a is inductive current；B is capacitance voltage.
Fig. 7. inductive current that fault branch list branch submodule DCswitch2 records and capacitance voltage change curve,
Wherein a is inductive current；B is capacitance voltage.
Fig. 8. inductive current that non-faulting branch road list branch submodule DCswitch1 records and capacitance voltage change curve
Figure, wherein a is inductive current；B is capacitance voltage.
Fig. 9. inductive current that non-faulting branch road list branch submodule DCswitch3 records and capacitance voltage change curve
Figure, wherein a is inductive current；B is capacitance voltage.
Detailed description of the invention
The present invention provides a kind of fault detect being applicable to multiple-limb low-voltage direct distribution system and partition method, below knot
Conjunction accompanying drawing is explained.
It is illustrated in figure 1 multiple-limb low-voltage direct distribution system protection structural representation.Fig. 1 is the DC distribution of 4 nodes
System, in Fig. 1, each node has three (being not limited to three), the most numbered node 1, and it branches into branch 1-1, branch
1-2, branch 1-3；Node 2, it branches into branch 2-1, branch 2-2, branch 2-3；Node 3, the rest may be inferred by analogy.This multiple-limb low pressure
Direct-flow distribution system is a multinode direct-flow distribution system, there is multiple branch at each node；Have how many at each node
Individual branch, then single branch submodule of corresponding configuration equal number；And at each node, configure a set of multiple-limb low-voltage direct
Distribution system is protected；Input the first inductance L1, the second inductance L2 of single branch submodule connects of two nodes respectively
Branch, the output of single branch submodule is protected with the multiple-limb low-voltage direct distribution system at other node and is connected；
Consist of the first inductance L1, the first electronic switch ES1, the 3rd inductance L3 and the electric current of described single branch submodule pass
Sensor CS connects, and one end of the second electronic switch ES2 and the common junction of the first electronic switch ES1 and the 3rd inductance L3 connect,
The other end of the second electronic switch ES2 and the second inductance L2 connect；Upper end after electric capacity C1, voltage sensor VS parallel connection and electric current
Sensor CS connects, and lower end and electronic switch ES2's and the second inductance L2's common junction is connected；The group of Ge Dan branch submodule
Become identical；Wherein, utilizing the detection of electric capacity C1 both end voltage the most faulty by protection branch, voltage sensor VS is used for detecting electricity
Hold the voltage u at C1 two endsC；Current sensor CS flows through the electric current i of inductance L3 for detectionL；First inductance L1 and the second inductance
L2, constitutes filter unit with electric capacity C1 time system is normal, when being broken down by protection branch road, it is to avoid cause adjacent legs
The acute variation of electric parameters and impact to the properly functioning and Fault Identification of other branch；3rd inductance L3, flows utilization
Cross the current detecting of this inductance and protected branch's whether fault, by protection branch properly functioning time, it will not be to DC distribution system
System impacts.
Described first electronic switch ES1 and the second electronic switch ES2 is two-way gate-controlled switch device；All use MOSFET,
IGBT or GTO, chooses the power capacity of above-mentioned gate-controlled switch device according to concrete application scenario；
Fig. 2 show fault detect and isolation FB(flow block).Fault detect and isolation comprise the steps:
1), when being run by protection multiple-limb low-voltage direct distribution system, Ge Dan branch submodule is surveyed by current sensor CS
Amount flows through the inductive current i of the 3rd inductance L3L, the capacitance voltage u at electric capacity C1 two ends is measured by voltage sensor VSC；
2) calculated, by the protection of multiple-limb low-voltage direct distribution system, the electricity that its Ge Dan branch submodule comprised collects
The absolute value of inducing current rate of change | diL/ dt | and capacitance voltage rate of change duC/ dt, and with the absolute value of inductive current rate of change |
diL/ dt | or capacitance voltage rate of change duCThe change of/dt detects by protection multiple-limb low-voltage direct distribution as failure criterion
Whether system breaks down, and any of which criterion meets and i.e. thinks that respective branches DC line/cable exists fault；
3) for there is the branch of fault, the protection of multiple-limb low-voltage direct distribution system the first electronic switch ES1 is controlled
Disconnect, the second electronic switch ES2 closes；The multiple-limb low-voltage direct distribution system protection of fault branch both sides in like manner detects fault
And control electronic switch, it is achieved the isolation of fault branch.Properly functioning branch road will not be isolated, and is prevented effectively from expansion power failure model
Enclose；
4) protection of multiple-limb low-voltage direct distribution system sends and controls the first electronic switch ES1 disconnection, the second electronic switch
After the order of ES2 Guan Bi, continue detection and flow through the electric current of inductance in single branch submodule, if this electric current is continuously less than k4in, then
Think that the first electronic switch ES1 in this branch's submodule disconnects；If this electric current is more than k4inAnd the duration reaches Tset2In the least
Second, then controlled the first electronic switch in other all branches submodule of this node by the protection of multiple-limb low-voltage direct distribution system
ES1 disconnects, the second electronic switch ES2 Guan Bi；Wherein, k4For the safety factor less than 1, more than 0, inProperly functioning for this branch
Electric current.
To contain the multiple-limb low-voltage direct power distribution system of 3 Ge Dan branch submodule DCswitch1～DCswitch3 shown in Fig. 3
Blanket insurance protect as a example by explanation.Wherein alternating voltage grade is 380V, and straight-flow system electric pressure is 750V.Safety factor k1And k2Point
Do not take 1.2 and-1.2, k3Take 0.8, k4Take 0.15, Tset2Take 100ms, Tset1Take 50ms, Tset3Take 10ms.Figure is gained merit and idle
Unit is respectively MW and MVar, and voltage unit is kV.Fault moment is 1s, and trouble duration is 0.5s.
The threshold value of each criterion:
In failure criterion 1, Δ imaxWith Δ umaxIt is to try to achieve according to the principle described in criterion 1, Δ imax=5kA/s, Δ
umax=-20kV/s.
In failure criterion 2, k3Take 0.8, unFor 750V.
Threshold value in failure criterion 3 is with criterion 1 and criterion 2.
1), when course of emergency crosses the short trouble of resistance 1 ohm at trouble point fault in figure 3, fault can be recorded and prop up
Inductive current iL in road list branch submodule DCswitch2 and capacitance voltage Uc is as shown in Figure 4.After fault, Uc is significantly lower than
Threshold value, therefore failure criterion 1 meets；Current changing rate absolute value after fault is about 286kA/s, voltage change ratio be about-
606kV/s, therefore failure criterion 2 also meets.Protection determines rapidly fault branch, and by controlling the electricity in DCswitch2
Sub-switch isolation fault.
DCswitch1 and DCswitch3, inductive current iL and electric capacity that i.e. non-faulting branch road list branch submodule records are electric
Pressure Uc is the most as shown in Figure 5, Figure 6.In the two, current changing rate maximum absolute value reduces less than 2.5kA/s, voltage change ratio
Not Wei 14kV/s and 6kV/s, therefore failure criterion is all unsatisfactory for, and non-faulting branch road will not be excised by mistake.
Further transition resistance is increased to 3 ohm, when still having short trouble at fault, divide according to fault branch list
Propping up the inductive current iL in submodule DCswitch2 and capacitance voltage Uc to understand, now voltage is higher than threshold value, and therefore fault is sentenced
It is unsatisfactory for according to 2.But, fault after-current rate of change absolute value is about 19kA/s, and voltage change ratio is about-210kV/s, so therefore
Barrier criterion 1 is satisfied, and therefore protection remains to rapid Judging fault, and isolates by controlling the electronic switch in DCswitch2
Fault.
And for non-faulting branch road list branch submodule DCswitch1 and DCswitch3, its inductive current iL recorded
The rate of change calculating the voltage and current in non-faulting branch with capacitance voltage Uc is all unsatisfactory for criterion.Non-faulting branch road will not be by
Excision by mistake.This method protection has the ability of stronger tolerance transition resistance.
2) in figure 3, being moved to by trouble point fault between 0.5 [mH] and 0.125 [ohm], i.e. trouble point is to circuit sidesway
Dynamic.Transition resistance 0.1 ohm, be short-circuited fault, can obtain the electricity that fault branch list branch submodule DCswitch1 records
Inducing current iL and capacitance voltage Uc is as shown in Figure 7.Owing to failure criterion 1, failure criterion 2 are satisfied by, therefore protection differentiates rapidly
Fault, and by controlling the electronic switch isolated fault in DCswitch1.
DCswitch1 and DCswitch3, inductive current iL and electric capacity that i.e. non-faulting branch road list branch submodule records are electric
Pressure Uc is the most as shown in Figure 8, Figure 9.Owing to failure criterion is all unsatisfactory for, therefore non-faulting branch road will not be excised by mistake.
Claims (4)
1. one kind is applicable to multiple-limb low-voltage direct distribution system, it is characterised in that described multiple-limb low-voltage direct distribution system
It is a multinode direct-flow distribution system, at each node, there is multiple branch；Have how many branches at this node, then correspondence is joined
Put single branch submodule of equal number；And at each node, configure the protection of a set of multiple-limb low-voltage direct distribution system；Single
Input the first inductance L1 of branch's submodule, the second inductance L2 connect a branch of two nodes, single branch submodule respectively
The output of block is protected with the multiple-limb low-voltage direct distribution system at other node and is connected；
Described single branch submodule consist of the first inductance L1, the first electronic switch ES1, the 3rd inductance L3 and current sensor
CS connects, and one end of the second electronic switch ES2 and the common junction of the first electronic switch ES1 and the 3rd inductance L3 connect, and second
The other end of electronic switch ES2 and the second inductance L2 connect；Upper end after electric capacity C1, voltage sensor VS parallel connection and current sense
Device CS connects, and lower end and electronic switch ES2's and the second inductance L2's common junction is connected；The composition phase of Ge Dan branch submodule
With；Wherein, the current detecting utilize electric capacity C1 both end voltage, flowing through inductance L3 is protected branch the most faulty, voltage sensor
Device VS is for detecting the voltage u at electric capacity C1 two endsC；Current sensor CS flows through the electric current i of inductance L3 for detectionL；First inductance
L1 and the second inductance L2, constitutes filter unit with electric capacity C1 time system is normal, when being broken down by protection branch road, it is to avoid
The acute variation of adjacent legs electric parameters is caused to impact to the properly functioning and Fault Identification of other branch；3rd inductance
L3, flows through utilization the current detecting of this inductance and is protected branch's whether fault, by protection branch properly functioning time, it will not be right
Direct-flow distribution system impacts.
It is applicable to multiple-limb low-voltage direct distribution system the most according to claim 1, it is characterised in that described first electronic cutting
Closing ES1 and the second electronic switch ES2 is two-way gate-controlled switch device；All use MOSFET, IGBT or GTO, according to concrete application
Occasion chooses the power capacity of above-mentioned gate-controlled switch device；When being protected branch road properly functioning when, the first electronic switch ES1
Guan Bi, the second electronic switch ES2 disconnect；When this branch trouble being detected, by the protection control of multiple-limb low-voltage direct distribution system
Make the first electronic switch ES1 open, second electronic switch ES2 Guan Bi.
3. being applicable to fault detect and the partition method of multiple-limb low-voltage direct distribution system described in claim 1, it is special
Levy and be, the current sensor in the protection of same multiple-limb low-voltage direct distribution system and the electric current that obtains of voltage sensor measurement
All send to information of voltage this multiple-limb low-voltage direct distribution system protection carry out unifying computing, it is achieved fault detect and every
From, comprise the steps:
1), when being run by protection multiple-limb low-voltage direct distribution system, Ge Dan branch submodule measures stream by current sensor CS
Cross the inductive current i of the 3rd inductance L3L, the capacitance voltage u at electric capacity C1 two ends is measured by voltage sensor VSC；
2) calculated, by the protection of multiple-limb low-voltage direct distribution system, the inductance electricity that its Ge Dan branch submodule comprised collects
The absolute value of rheology rate | diL/ dt | and capacitance voltage rate of change duC/ dt, and with the absolute value of inductive current rate of change | diL/
Dt | or capacitance voltage rate of change duC/ dt detects by whether protection multiple-limb low-voltage direct distribution system is sent out as failure criterion
Raw fault, any of which criterion meets and i.e. thinks that respective branches DC line/cable exists fault；
3) for there is the branch of fault, multiple-limb low-voltage direct distribution system protection control the first electronic switch ES1 disconnect,
Second electronic switch ES2 Guan Bi；The multiple-limb low-voltage direct distribution system protection of fault branch both sides in like manner detects fault and controls
Electronic switch processed, it is achieved the isolation of fault branch, properly functioning branch road will not be isolated, and is prevented effectively from expansion power failure range；
4) protection of multiple-limb low-voltage direct distribution system sends control the first electronic switch ES1 disconnection, the second electronic switch ES2 closes
After the order closed, continue detection and flow through the electric current of inductance in single branch submodule, if this electric current is continuously less than k4in, then it is assumed that
The first electronic switch ES1 in this branch's submodule disconnects；If this electric current is more than k4inAnd the duration reaches Tset2Millisecond,
Then controlled the first electronic switch ES1 in other all branches submodule of this node by the protection of multiple-limb low-voltage direct distribution system
Disconnect, the second electronic switch ES2 closes；Wherein, k4For the safety factor less than 1, more than 0, inFor the electricity that this branch is properly functioning
Stream.
The most according to claim 3, be applicable to fault detect and the partition method of multiple-limb low-voltage direct distribution system, it is special
Levying and be, described failure criterion includes:
Failure criterion 1: if the absolute value of inductive current rate of change that certain single branch submodule records | diL/ dt | more than the door arranged
Threshold value Δ ith, and capacitance voltage rate of change duC/ dt is less than the threshold value Δ u arrangedth, then judge that this list branch submodule is protected
There is fault in the direct current branch protected；I.e. criterion is 1 to be: | diL/dt|>ΔithAnd duC/dt<Δuth, wherein, Δ ith=k1Δ
imax, Δ uth=k2Δumin, k1And k2Be greater than 1 respectively, safety factor less than 2 with less than-1, more than-2, it is contemplated that use
Bicharacteristic amount judges, the two coefficient can the most suitably take close to 1 and-1；ΔimaxIt is: 1) in system normal course of operation,
2) at DC line/cable outlet that in the protection of same multiple-limb low-voltage direct distribution system, other single branch submodule is protected
Fault, 3) single branch submodule of being adjusted corresponding by protection DC line/cable end piece fault time, branch's adjusted
The maximum of the inductive current rate of change absolute value in module；ΔuminIt is: 1) in system normal course of operation, 2) same many points
Fault at DC line/cable outlet that in the protection of low-voltage direct distribution system, other single branch submodule is protected, 3) institute
Single branch submodule of adjusting corresponding by protection DC line/cable end piece fault time, in the single branch submodule adjusted
The minimum of a value of capacitance voltage rate of change；
Failure criterion 2: if certain single branch submodule is at Tset3The capacitance voltage u recorded continuously in Hao MiaoCIt is below the low electricity arranged
Pressure gate threshold value uth, illustrate that the branch road that this branch's submodule is protected exists fault；Low-voltage threshold value uthCalculating: uth=
k3un, wherein, k3Be less than 1, safety factor more than 0, unIt it is multiple-limb low-voltage direct distribution system rated voltage；Single branch
In submodule, the second electronic switch ES2 disconnects, the first electronic switch ES1 closes, during restoring electricity, and this criterion T of lockingset1
Millisecond；
Failure criterion 3: if can obtain branch road both sides configuration multiple-limb low-voltage direct distribution system protection information, then for
The Liang Gedan branch submodule of same DC line/cable both sides, if any one in following 3 conditions meets, i.e. meets a)
Both sides inductive current rate of change absolute value is all higher than set threshold value；B) capacitance voltage rate of change in both sides is respectively less than set
Threshold value；C) side inductive current rate of change absolute value is little more than set threshold value and opposite side capacitance voltage rate of change
In set threshold value, then judge that this direct current branch exists fault；Each threshold value setting method is sentenced with failure criterion 1 and fault
According to 2.
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| CN111740663A (en) * | 2020-05-18 | 2020-10-02 | 北京理工大学 | Method for inhibiting transition process of three-phase four-switch fault-tolerant control system |
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|---|---|---|---|---|
| CN103872686A (en) * | 2014-03-31 | 2014-06-18 | 国网上海市电力公司 | Power distribution network rack wiring structure |
| CN105226634A (en) * | 2014-05-27 | 2016-01-06 | 首瑞（北京）投资管理集团有限公司 | A kind of (TT) distribution system |
| CN105515199A (en) * | 2016-01-13 | 2016-04-20 | 山东大学 | Distributed fault detection method for intelligent power distribution network |
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2016
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| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103872686A (en) * | 2014-03-31 | 2014-06-18 | 国网上海市电力公司 | Power distribution network rack wiring structure |
| CN105226634A (en) * | 2014-05-27 | 2016-01-06 | 首瑞（北京）投资管理集团有限公司 | A kind of (TT) distribution system |
| CN105515199A (en) * | 2016-01-13 | 2016-04-20 | 山东大学 | Distributed fault detection method for intelligent power distribution network |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
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| CN111740663A (en) * | 2020-05-18 | 2020-10-02 | 北京理工大学 | Method for inhibiting transition process of three-phase four-switch fault-tolerant control system |
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