CN106711971A - Method for protecting double-end direct current distribution network - Google Patents
Method for protecting double-end direct current distribution network Download PDFInfo
- Publication number
- CN106711971A CN106711971A CN201710070114.7A CN201710070114A CN106711971A CN 106711971 A CN106711971 A CN 106711971A CN 201710070114 A CN201710070114 A CN 201710070114A CN 106711971 A CN106711971 A CN 106711971A
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- Prior art keywords
- region
- bus
- direct current
- fault
- distribution net
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
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Classifications
-
- 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
- H02H7/268—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
Abstract
The invention discloses a method for protecting a double-end direct current distribution network. The method comprises the steps of: 1) performing regional division on the double-end direct current distribution network by using a direct current circuit breaker and a direct current bus; 2) when the direct current distribution network has a single-pole ground or double-pole short-circuit fault, judging the fault current direction in each divided region; 3) performing information interaction on the fault current direction in each region, thus distinguishing the fault type; and 4) removing the fault according to the fault type. The line of the direct current distribution network is short, and the information interaction is only performed in the adjacent regions, so that the influence of delay on data transmission can be ignored; only digital signals are transmitted, so that the transmission time can be nearly ignored; the current direction is changed on the millisecond level, and the fault is removed by using the solid direct current circuit breaker, so that the operation speed is high, and quick protection of the double-end direct current distribution network can be realized; and the scheme has certain transition resistance tolerance, and is thus universal for protection of double-end direct current distribution networks.
Description
Technical field
The present invention relates to a kind of DC distribution net protection field, more particularly to a kind of protection side of both-end DC distribution net
Method.
Background technology
In recent years, the fast-developing construction in city expands traditional AC distribution net radius of electricity supply, brings power supply and walks
A series of problems, such as corridor anxiety, down town electricity shortage.On the other hand, power supply also there occurs significant change with load, be distributed
Formula power supply and DC load accounting more and more higher, but by DC/AC converter incoming transport power distribution networks, can not only influence electric energy
Quality, reduction electric energy service efficiency, can also increase extra investment construction cost.Power Electronic Technique and flexible converter technology
Development driven direct-current micro-grid, the rise of DC distribution net.Compared to AC distribution net, DC distribution net has power supply capacity
Greatly, the quality of power supply is good, reliability is high, cost of investment is few, be suitable to the series of advantages such as regenerative resource access, therefore as in recent years
Carry out the focus of academia's research.However, DC bus capacitor repid discharge when DC distribution net breaks down, it is desirable to which protection is in number milli
Action in second, realizes quick detection, identification and the positioning of failure.Traditional protection project compatibility is poor, and protection equipment
Imperfection, the protection to DC distribution net brings huge challenge.
At present, the scheme of DC distribution net protection is still in theoretical research stage, and DC distribution net Protective strategy is main
Concentrate on single-end DC power distribution network, for both-end and Multi-port direct-current distribution network research still in blank or theoretical research rank
Section.Traditional AC distribution net protection scheme such as overcurrent, voltage, differential protection appts etc. are because selectivity and problem of tuning are straight
Especially applicability is poor in both-end or Multi-port direct-current distribution network for stream power distribution network, and the application of distance protection is limited to the limit of algorithm
System, differential protection is then influenceed larger when fault current two-forty changes by data syn-chronization.It can be seen that, traditional AC distribution net
Protection scheme is poor to the applicability of DC distribution net, it is necessary to protection scheme of the research suitable for DC distribution net.
The content of the invention
Goal of the invention：It is an object of the present invention to provide a kind of guard method of both-end DC distribution net, DC distribution is capable of achieving
Quick excision when DC feeder and dc bus occur monopole ground connection or bipolar short trouble in net.
Technical scheme：The invention provides a kind of guard method of both-end DC distribution net, the method is comprised the following steps：
1) region division is carried out to both-end DC distribution net using dc circuit breaker and dc bus；
2) there is monopole ground connection or during bipolar short trouble when DC distribution net, judge step 1) it is former in each region for dividing
The barrier sense of current；
3) information exchange is carried out to fault current direction in each region, so as to distinguish fault type；
4) according to fault type, failure removal is carried out.
Step 1) in, the method that region division is carried out to both-end DC distribution net using dc circuit breaker and dc bus
For：Dc bus two ends in both-end DC distribution net are respectively provided with dc circuit breaker, match somebody with somebody direct current by boundary of dc bus
Power network is divided into multiple regions, makes to be respectively equipped with two dc circuit breakers in each region.
Step 2) in, it is stipulated that DC current flows to DC feeder for positive direction from dc bus in each region, from direct current feedback
Line flows to dc bus for negative direction.
Step 3) in, information exchange is realized by the intelligent electronic device with communication function, intelligent electronic device
It is integrated in dc circuit breaker.
Step 3) and step 4) in fault type be DC feeder failure or DC bus fault.
When the sense of current for flowing through is timing, electronic equipment output digit signals 1；When the sense of current for flowing through is to bear,
Intelligent electronic device output digit signals 0.
The intelligent electronic device of adjacent area carries out information exchange, if the data signal exported in certain region is " 11 ",
It is judged as in the region that DC feeder breaks down；If the data signal exported in two neighboring region is all " 00 ", judge
It is the dc bus failure in the middle of the two neighboring region.Therefore, if the data signal exported in certain region is
" 11 ", then disconnect two dc circuit breakers in the region, with isolated DC feeder fault；If the number exported in two neighboring region
Word signal is all " 00 ", then the dc circuit breaker of output " 0 " in the two neighboring region is disconnected, with isolated DC bus-bar fault.
Beneficial effect：Compared with prior art, the present invention has advantages below：
(1) change of the sense of current is combined with region division when the present invention is by failure, can be realized by different signals straight
Stream feeder line is distinguished with DC bus fault, so as to be protected to DC distribution net；
(2) method of the present invention is based on communication, but DC distribution netting twine road is shorter and information exchange of the invention is only in phase
Neighbouring region is carried out, influence of the negligible time delay to data transfer, and only transmits data signal so that transmission time is substantially negligible
Disregard；The sense of current changes all in millisecond rank, and carries out failure removal using solid dc circuit breaker so that the protection scheme
Quick action, is capable of achieving the quick protection of both-end DC distribution net；
(3) though theory shows that the method can just occur sense of current change, DC distribution net when low-resistance monopole is grounded
Transition resistance is smaller so that the program still has certain resistance to transition resistance ability, therefore for the allusion quotation of both-end DC distribution net
Type fault type is excluded has general applicability.
Brief description of the drawings
The typical both-end DC distribution net schematic diagrames of Fig. 1；
Dc circuit breaker configuration schematic diagram in Fig. 2 the solution of the present invention；
Both-end direct current network region division schematic diagram in Fig. 3 the solution of the present invention；
Fault current direction schematic diagram when Fig. 4 both-end DC distributions net occurs bipolar short-circuit；
There is fault current direction schematic diagram when monopole is grounded in Fig. 5 both-end DC distributions net；
The region division and fault current direction schematic diagram of both-end DC distribution net in Fig. 6 the solution of the present invention.
Specific embodiment
A kind of guard method of both-end DC distribution net, comprises the following steps.
(1) region division is carried out to both-end DC distribution net using dc circuit breaker and dc bus.
Fig. 1 is typical both-end DC distribution net, specifically, in figure shows the dc bus that numbering is #1 to #6, with
And the DC feeder (in Fig. 1 use straight line --- represent) that numbering is 1 to 7, each dc bus two ends is each provided with direct current interruption
Device, in figure, dc circuit breaker iconRepresent, be provided between two dc circuit breakers with thicker straight line table
The dc bus for showing is (in Fig. 1), dc circuit breaker is two-by-two one group, is matched somebody with somebody direct current as boundary using dc bus
Power network is divided into multiple regions, and two dc circuit breakers are provided with each region, and each region two ends is dc bus.#1’
And #2 ' is ac bus.
Fig. 2 is the dc circuit breaker configuration figure in a region, it is stipulated that dc circuit breaker two ends are A, B point, each direct current
The A points of breaker are the point of the relatively close dc bus adjacent with the dc circuit breaker, and B points are disconnected with the direct current to be relatively distant from
The point of the adjacent dc bus of road device.In addition, rated current flows to DC feeder for positive direction from dc bus, on the contrary be it is negative,
That is, the electric current of each dc circuit breaker is flowed through, B points is flowed to for positive direction from A points, A points are flowed to for negative direction from B points.
Realize that both-end DC distribution web area division result is as shown in Figure 3 with dc circuit breaker and dc bus position.
In the example depicted in fig. 3, DC distribution net is divided into 4 regions (Zone1, Zone2, Zone3, Zone4), first area
(Zone1) two dc circuit breakers B1, B2, and DC feeder 1 are provided with；Two direct currents are provided with second area (Zone2)
Breaker B3, B4, and DC feeder 2；Two dc circuit breakers B5, B6, and direct current feedback are provided with 3rd region (Zone3)
Line 3；Two dc circuit breakers B7, B8, and DC feeder 4 are provided with 4th region (Zone4).Dc circuit breaker B1 and label
For #1 dc bus be connected, dc circuit breaker B2, B3 are connected with the dc bus marked as #3, dc circuit breaker B4, B5 and
Dc bus marked as #4 is connected, and dc circuit breaker B6, B7 are connected with the dc bus marked as #5, dc circuit breaker B8 and
Dc bus marked as #2 is connected.F1 represents DC feeder failure, and F2 represents DC bus fault.
(2) when DC distribution net occurs monopole ground connection or bipolar short trouble, fault current direction in each region is judged.
(3) information exchange is carried out to fault current direction in each region, so as to distinguish fault type.
I, the principle according to fault current walking direction fault type.
Two ends fault current expression formula is when occurring bipolar short-circuit on both-end DC distribution net DC feeder：
Wherein, E1And E2Both-end DC distribution net equivalent source, including DC bus capacitor and DC side electricity are represented respectively
Source.Z1pAnd Z2pPositive pole circuit to the equiva lent impedance of trouble point, Z are represented respectively1n、Z2nNegative pole circuit is represented respectively arrives trouble point
Equiva lent impedance, I1p、I2pBoth-end DC distribution net both sides fault current is represented respectively.It can be seen that, for the bipolar short circuit event of metallicity
Barrier, DC distribution net both sides fault current direction is just.Fault current direction schematic diagram is as shown in figure 4, bipolar short when occurring
During the failure of road, both sides source current flows to trouble point.
There is monopolar grounding fault for both-end DC distribution net, two ends fault current expression formula is：
ZFTo there is transition resistance during monopolar grounding fault.
If meeting E1=E2, formula (3) and (4) are represented by
It can be seen that, if both sides power supply is equal, DC distribution net both sides fault current direction is when there is monopolar grounding fault
Just.
If being unsatisfactory for E1=E2, then only meetAndWhen, reach
Sufficient two ends fault current is negative.I.e. in the monopolar grounding fault of low-resistance, still meet both sides fault current direction and be just.With it is double
Extremely short road failure is similar to, and when there is monopolar grounding fault and relatively low transition resistance, both sides source current flows to trouble point, such as
Shown in Fig. 5.
II, the method according to fault current walking direction fault type.
Based on the difference in zone current direction, each region when realizing failure using the intelligent electronic device based on communication function
The interaction of fault message.Electronic mutual inductor type intelligent electronic device with communication function is integrated in DC breaker
Integrated-type intelligent isolated DC breaker is constituted, electronic mutual inductor type intelligent electronic device is by multiple processor groups into treatment
Device can constantly be monitored analysis to measured values such as voltage, electric currents, and will measure or the data that calculate are by based on work
The communication system of industry standard agreement sends outside or user to.If the sense of current for flowing through intelligent electronic device is just intelligence
It is 1 that current direction signal is converted to data signal by energy electronic equipment, if the sense of current for flowing through intelligent electronic device is negative,
It is 0 that current direction signal is converted to data signal by intelligent electronic device.
Region division is as shown in Figure 6 with fault current direction.In the example depicted in fig. 6, DC distribution net is divided into 4
Individual region (Zone1, Zone2, Zone3, Zone4), is provided with two dc circuit breakers B1, B2 in first area (Zone1), and
DC feeder 1；Two dc circuit breakers B3, B4, and DC feeder 2 are provided with second area (Zone2)；3rd region
(Zone3) two dc circuit breakers B5, B6, and DC feeder 3 are provided with；Two direct currents are provided with 4th region (Zone4)
Breaker B7, B8, and DC feeder 4.Dc circuit breaker B1 is connected with the dc bus marked as #1, dc circuit breaker B2,
B3 is connected with the dc bus marked as #3, and dc circuit breaker B4, B5 are connected with the dc bus marked as #4, dc circuit breaker
B6, B7 are connected with the dc bus marked as #5, and dc circuit breaker B8 is connected with the dc bus marked as #2.F1 represents direct current
Feeder fault, F2 represents DC bus fault.
When there is DC feeder failure, the both sides sense of current is just, therefore, the intelligent electronic device of adjacent area enters
Row information is interacted, if being integrated in two intelligent electronic device output signals of dc circuit breaker in a certain region meets " 11 ",
It is judged as that the region occurs DC feeder failure.If DC bus fault, then the sense of current of the inflow dc bus both sides
Be it is negative, therefore, if intelligent electronic device and adjacent area carry out information exchange result for continuous " 00 " occurs in adjacent area,
It is judged as the DC bus fault in the middle of the adjacent area.
(4) according to fault type, failture evacuation is carried out.
When the operating criterion described in step (3) is met, dc circuit breaker action realizes DC feeder with dc bus event
The excision of barrier.That is, when two intelligent electronic device output signals of dc circuit breaker meet " 11 " in being integrated in a certain region,
Judge that the region occurs DC feeder failure, now disconnect in the region dc circuit breaker with isolated DC feeder fault；Work as phase
Continuously there is " 00 " in intelligent electronic device in adjacent two regions, then disconnect the two neighboring region and the direct current interruption of " 0 " occur
Device, so that isolated DC bus-bar fault.
The method of the present invention realizes that the mathematics in zone current direction is changed by intelligent electronic device, and utilizes unlike signal
Criterion realizes that DC feeder is distinguished and recognized with DC bus fault, can quickly exclude the failure in both-end DC distribution net, and
Can generally be applicable.
Claims (9)
1. a kind of guard method of both-end DC distribution net, it is characterised in that the method is comprised the following steps：
1) region division is carried out to both-end DC distribution net using dc circuit breaker and dc bus；
2) there is monopole ground connection or during bipolar short trouble when DC distribution net, judge step 1) failure is electric in each region for dividing
Stream direction；
3) information exchange is carried out to fault current direction in each region, so as to distinguish fault type；
4) according to the fault type, failure removal is carried out.
2. method according to claim 1, it is characterised in that step 1) in, the utilization dc circuit breaker and direct current are female
Line is to the method that both-end DC distribution net carries out region division：Dc bus two ends in both-end DC distribution net set respectively
Dc circuit breaker is put, DC distribution net is divided into multiple regions by boundary of dc bus, make to be respectively equipped with each region
Two dc circuit breakers.
3. method according to claim 2, it is characterised in that step 2) in, it is stipulated that electric current is from dc bus in each region
DC feeder is flowed to for positive direction, dc bus is flowed to for negative direction from DC feeder.
4. method according to claim 3, it is characterised in that step 3) in, described information interaction is by with communication
What the intelligent electronic device of function was realized.
5. method according to claim 4, it is characterised in that the intelligent electronic device is integrated in the direct current interruption
Device.
6. method according to claim 5, it is characterised in that the fault type is DC feeder failure or dc bus
Failure.
7. method according to claim 6, it is characterised in that when the sense of current for flowing through is timing, the smart electronicses
Equipment output digit signals 1；When the sense of current for flowing through is to bear, the intelligent electronic device output digit signals 0.
8. method according to claim 7, it is characterised in that the intelligent electronic device of adjacent area carries out information exchange,
If the data signal exported in certain region is " 11 ", it is judged as in the region that DC feeder breaks down；If two neighboring area
The data signal exported in domain is all " 00 ", then be judged as being located at the dc bus in the middle of the two neighboring region and break down.
9. method according to claim 8, it is characterised in that if the data signal exported in certain region is " 11 ", break
Open two dc circuit breakers in the region；If the data signal exported in two neighboring region is all " 00 ", this is disconnected adjacent
The dc circuit breaker of " 0 " is exported in two regions.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201710070114.7A CN106711971A (en) | 2017-02-09 | 2017-02-09 | Method for protecting double-end direct current distribution network |
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201710070114.7A CN106711971A (en) | 2017-02-09 | 2017-02-09 | Method for protecting double-end direct current distribution network |
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| CN106711971A true CN106711971A (en) | 2017-05-24 |
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| CN201710070114.7A Pending CN106711971A (en) | 2017-02-09 | 2017-02-09 | Method for protecting double-end direct current distribution network |
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Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN107492871A (en) * | 2017-07-10 | 2017-12-19 | 华北电力大学 | A kind of flexible direct current line direction longitudinal protection method based on total current amount |
| CN114325224A (en) * | 2021-12-14 | 2022-04-12 | 国网浙江省电力有限公司电力科学研究院 | Fault section positioning method based on real-time data of distribution network |
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| WO2011157305A1 (en) * | 2010-06-14 | 2011-12-22 | Abb Research Ltd | Fault protection of hvdc transmission lines |
| CN103066573A (en) * | 2012-12-13 | 2013-04-24 | 国网智能电网研究院 | Modular multi-level multi-terminal flexible direct current system direct current fault handling method |
| CN106058828A (en) * | 2016-07-18 | 2016-10-26 | 天津大学 | Multi-terminal flexible DC power grid line direction pilot protection method |
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Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN107492871A (en) * | 2017-07-10 | 2017-12-19 | 华北电力大学 | A kind of flexible direct current line direction longitudinal protection method based on total current amount |
| CN107492871B (en) * | 2017-07-10 | 2019-01-15 | 华北电力大学 | A kind of flexible direct current line direction longitudinal protection method based on total current amount |
| CN114325224A (en) * | 2021-12-14 | 2022-04-12 | 国网浙江省电力有限公司电力科学研究院 | Fault section positioning method based on real-time data of distribution network |
| CN114325224B (en) * | 2021-12-14 | 2023-09-22 | 国网浙江省电力有限公司电力科学研究院 | Fault interval positioning method based on distribution network real-time data |
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