CN107346003A - A kind of voltage source converter fault detecting and positioning method and system - Google Patents
A kind of voltage source converter fault detecting and positioning method and system Download PDFInfo
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- CN107346003A CN107346003A CN201610296443.9A CN201610296443A CN107346003A CN 107346003 A CN107346003 A CN 107346003A CN 201610296443 A CN201610296443 A CN 201610296443A CN 107346003 A CN107346003 A CN 107346003A
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- transverter
- bridge
- positioning method
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
- G01R31/00—Arrangements for testing electric properties; Arrangements for locating electric faults; Arrangements for electrical testing characterised by what is being tested not provided for elsewhere
- G01R31/40—Testing power supplies
- G01R31/42—AC power supplies
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- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02M—APPARATUS FOR CONVERSION BETWEEN AC AND AC, BETWEEN AC AND DC, OR BETWEEN DC AND DC, AND FOR USE WITH MAINS OR SIMILAR POWER SUPPLY SYSTEMS; CONVERSION OF DC OR AC INPUT POWER INTO SURGE OUTPUT POWER; CONTROL OR REGULATION THEREOF
- H02M7/00—Conversion of ac power input into dc power output; Conversion of dc power input into ac power output
- H02M7/42—Conversion of dc power input into ac power output without possibility of reversal
- H02M7/44—Conversion of dc power input into ac power output without possibility of reversal by static converters
- H02M7/48—Conversion of dc power input into ac power output without possibility of reversal by static converters using discharge tubes with control electrode or semiconductor devices with control electrode
- H02M7/483—Converters with outputs that each can have more than two voltages levels
- H02M7/4835—Converters with outputs that each can have more than two voltages levels comprising two or more cells, each including a switchable capacitor, the capacitors having a nominal charge voltage which corresponds to a given fraction of the input voltage, and the capacitors being selectively connected in series to determine the instantaneous output voltage
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- Engineering & Computer Science (AREA)
- Power Engineering (AREA)
- Physics & Mathematics (AREA)
- General Physics & Mathematics (AREA)
- Locating Faults (AREA)
Abstract
The invention discloses a kind of voltage source converter fault detecting and positioning method and system, net side Earth design method in the voltage source converter topology that transless mode in a kind of flexible direct current power transmission system accesses direct current network is specifically provided, a kind of mode is detection fault current, compare bridge arm reactor current size and current on line side transformer measurement size of current, according to bridge arm current direction and current on line side direction, difference stream size between the two is calculated, difference stream is more than given numerical value and thinks that it is failure side to change side.Under the conditions of locking transverter in short-term, detect both sides transverter residual voltage, if full bridge structure, fully closed lock or half closedown mode in short-term can be passed through, ensure that zero sequence earth current will not be transferred to offside current conversion station by DC side, half-bridge structure can detect unilateral transverter output residual voltage size by closedown mode in short-term, more than certain stabilization delay judgement it is failure side more than given numerical value, it is believed that this side is failure side.
Description
Technical field
The invention belongs to Power System Flexible AC-HVDC technical field, and in particular to a kind of flexible DC power transmission
Transless mode accesses net side Earth design side in the voltage source converter topology of direct current network in system
Method and system.
Background technology
In modern AC power distribution network, one side big city load density constantly increases, transmission and distribution network scale it is continuous
Expand, the problems such as being limited by capacity of short circuit, electromagnetic looped network, power distribution network typically using high pressure subregion, in press off ring
The method of operation, cause system equipment utilization rate low, reliability decrease, another aspect client to power supply reliability,
The requirement of the quality of power supply is improved constantly again, and sensitive load gradually increases in large size city, and short term outage also can
Bring the even serious social influence of larger economic loss.Flexible DC power transmission uses voltage source converter, can
With separately adjustable active and idle transmission, flexible direct current technology is that the existing power distribution network of solution is of problems effectively
One of means, flexible DC power transmission can realize that AC network interconnects in the case where not increasing capacity of short circuit, real
Existing AC network Electromagnetic coupling, improve operation of power networks reliability, the lifting quality of power supply and operation of power networks efficiency.
AC-DC interconnecting power network based on flexible direct current power transmission and distribution is one of trend of power network development, based on modularization
The development of multilevel converter, solve voltage-sharing and loss of the puzzlement based on the development of two level flexible DC power transmissions
Big problem, while AC system harmonic wave is reduced, transless connection connection AC system is turned into a kind of possible.
So that current conversion station overall investment and volume are reduced and are possibly realized.
When flexible direct current power transmission system voltage source converter accesses power network using transless mode, when exchange is
For system when breaking down, half-bridge MMC is similar with full-bridge MMC fault characteristic, and flexible loop network control device can not be every
From zero sequence.Such as there is phase voltage to be promoted to line voltage for AG (single-phase earthing) failure, non-faulting phase voltage,
ABC three-phase currents keep symmetrical.Current conversion station 2 can also show the fault signature of singlephase earth fault, direct current
Existing power frequency common mode AC compounent is extruded, both sides control system can not predict failure and occur in which side, so as to all can
Startup separator control strategy suppresses zero-sequence component, both sides can be caused to adjust histamine result appearance jointly, due to both sides
Zero-sequence current component is really same nature, may finally be caused because both sides electric current loop adjusts asynchronous relation
Both sides inhibition is triggered to cancel out each other, it is therefore desirable to be positioned to fault detect, be accurately positioned failure side base plinth
On, determine that the cooperation of both sides suppresses zero-sequence component mode.
The content of the invention
It is an object of the invention to provide transless mode in a kind of flexible direct current power transmission system to access direct current network
Voltage source converter topology in net side Earth design method, it is characterised in that by detecting fault current,
Compare bridge arm reactor current and current on line side size, according to bridge arm current direction and current on line side direction, calculate
Difference stream size between the two, by relatively more each station difference stream size, judge that side occurs for actual earth fault.If nothing
Method judges side of being out of order by differential current computing method, if detecting that AC has residual voltage simultaneously, just passes through
In short-term under the conditions of locking transverter, both sides transverter residual voltage size is detected.Pass through residual voltage of relatively respectively standing
Size, judge that side occurs for actual earth fault.
In order to reach above-mentioned purpose, the technical solution adopted by the present invention is：
By calculating the difference stream size between bridge arm reactor current and current on line side, difference stream is more than given numerical value △
Iset, more than certain stabilization delay △ t1It is judged as failure side, difference stream is less than given numerical value △ IsetSide is judged as non-
Failure side, this positioning method can be carried out under the conditions of not locking transverter, wherein △ t10~5s of span.
The above-mentioned positioning failure side method is applied to the following neutral grounding mode of AC system：1) neutral point is not
Ground connection；2) Neutral Grounding through Resistance in Electrical；3) three kinds of modes of neutral by arc extinction coil grounding, wherein transverter
Topology can be half-bridge, and either class full bridge structure or half-bridge add the mixing bridge arm knot of full-bridge or class full-bridge to full-bridge
Structure.
Above-mentioned net side Earth design method, when singlephase earth fault, two phase ground occur for transverter one end
Failure side can be positioned in the case of failure, three-phase ground failure with poor stream mode is detected.
Above-mentioned net side Earth design method, if full bridge structure, fully closed lock or half in short-term can be passed through
Closedown mode, ensure that zero sequence earth current will not be delivered to offside current conversion station by DC side, half-bridge structure can be with
Pass through closedown mode in short-term, detection AC output residual voltage size, more than given numerical value △ UsetMore than one
Determine stabilization delay △ t2Side is judged as failure side, and other sides are non-faulting side.Wherein △ t20~5s of span.
A kind of net side Earth design system, the system include current detecting unit, zero sequence voltage detection unit,
Logic comparing unit and fault detect positioning unit.Wherein current detecting unit detection current on line side and bridge arm
Size of current.Zero sequence voltage detection unit detection output residual voltage size.Logic comparing unit is by calculating two
Transverter output residual voltage size is calculated under difference stream size, and barring condition between person.Logic is more single
Member is more than given numerical value △ I by calculating difference stream size between the two, difference streamset, it is delayed more than certain stabilization
△t1It is judged as failure side, difference stream is less than given numerical value △ IsetSide is judged as non-faulting side, and by closing in short-term
Under the conditions of locking transverter, compare AC residual voltage size, more than given numerical value △ UsetMore than certain stabilization
Dynamic delay △ t2 sides are judged as failure side, and other sides are non-faulting side, wherein 0~5s of △ t2 spans.Therefore
Barrier detection positioning unit combination both the above comparative result, first detection difference stream size failure judgement side, if nothing
Method judges side of being out of order by differential current computing method, starts locking transverter in short-term immediately, detects both sides transverter
Residual voltage size.By residual voltage size of relatively respectively standing, judge that side occurs for actual earth fault.
After such scheme, beneficial effects of the present invention are：
(1) a variety of compound detection modes can conveniently detect that ground short circuit occurs for alternating current net side in DC network
Transverter one end, be easy to transverter side to start residual voltage or electric current and suppress strategy.
(2) this method judges to be out of order behind side, and each transverter can cooperate in the controls to be reached altogether
With suppression zero-sequence current or voltage purpose.Fault current composition in preferable suppression system, is respectively changed for direct current network
Stream device normal operation provides safeguard.
Brief description of the drawings
When Fig. 1 is that both ends transverter is connected using transformerless DC mode, trouble point k1, k2 occurred for net side
Schematic diagram.
Fig. 2 is the topology of transverter in the present invention, and wherein bridge arm module can be half-bridge (HBSM), full-bridge
Or interior full-bridge (SFBSM) (FBSM).
Embodiment
Below with reference to drawings and the specific embodiments, technical scheme is described in detail.
It is an object of the invention to provide transless mode in a kind of flexible direct current power transmission system to access direct current network
Voltage source converter topology in net side Earth design method, a kind of mode be detection fault current, compare
Bridge arm reactor current size and current on line side transformer measurement size of current, according to bridge arm current direction and net side
The sense of current, difference stream size between the two is calculated, difference stream is more than given numerical value and thinks that it is failure side to change side, separately
A kind of mode is that unilateral transverter output residual voltage size is directly detected under locking transverter state in short-term, greatly
More than certain stabilization delay judgement it is failure side in given numerical value, under the conditions of locking transverter in short-term, inspection
Survey both sides transverter residual voltage, if full bridge structure, can by fully closed lock or half closedown mode in short-term,
Ensure that zero sequence earth current will not be transferred to offside current conversion station by DC side, half-bridge structure can be by closing in short-term
Lock mode, detects unilateral transverter output residual voltage size, is delayed more than given numerical value more than certain stabilization
It is judged as failure side.
In order to reach above-mentioned purpose, solution of the invention is：
A kind of voltage source converter net side Earth design method for accessing direct current network is proposed, by detecting event
Hinder electric current, compare bridge arm reactor current and current on line side size, according to bridge arm current direction and current on line side side
To the difference calculated between the two flows size, by relatively more each station difference stream size, judges actual earth fault generation
Side.Concrete scheme is：By calculating difference stream size between the two, difference stream is more than given numerical value △ Iset, exceed
Certain stabilization delay △ t1It is judged as failure side, difference stream is less than given numerical value △ IsetSide is judged as non-faulting side,
This positioning method can be carried out under the conditions of not locking transverter, wherein △ t10~5s of span.
If side of being out of order can not be judged by differential current computing method, if detecting that AC has zero sequence electric simultaneously
Pressure, then by locking transverter in short-term under the conditions of, detect both sides transverter residual voltage size.By relatively more each
Stand residual voltage size, judge that side occurs for actual earth fault.Embodiment is：If full bridge structure,
It can ensure that zero sequence earth current will not be delivered to by DC side by fully closed lock or half closedown mode in short-term
Offside current conversion station, half-bridge structure can detect AC output residual voltage size by closedown mode in short-term,
More than given numerical value △ UsetMore than certain stabilization delay △ t2Side is judged as failure side, and other sides are non-faulting
Side.Wherein △ t20~5s of span.
Above-mentioned positioning failure side method of stating is applied to the following neutral grounding mode of AC system：1) neutral point
It is earth-free；2) Neutral Grounding through Resistance in Electrical；3) three kinds of modes of neutral by arc extinction coil grounding, the wherein change of current
Device topology can be half-bridge, and either class full bridge structure or half-bridge add the mixing bridge arm of full-bridge or class full-bridge to full-bridge
Structure.
A kind of net side Earth design system specific embodiment is：The system includes current detecting unit, and zero
Sequence voltage detection unit, logic comparing unit and fault detect positioning unit.
Wherein current detecting unit detection current on line side and bridge arm current size.Zero sequence voltage detection unit detects
Export residual voltage size.Logic comparing unit is by calculating difference stream size between the two, and barring condition
Lower calculating transverter output residual voltage size.Logic comparing unit flows size by the difference calculated between the two,
Difference stream is more than given numerical value △ Iset, more than certain stabilization delay △ t1It is judged as failure side, difference stream is less than given
Numerical value △ IsetSide is judged as non-faulting side, and by locking transverter in short-term under the conditions of, detect the unilateral change of current
Device exports residual voltage size, more than given numerical value △ UsetMore than certain stabilization delay △ t2Side is judged as event
Hinder side, other sides are non-faulting side, wherein △ t20~5s of span.More than fault detect positioning unit combines
Two kinds of comparative results, first detection difference stream size failure judgement side, if can not be judged by differential current computing method
It is out of order side, if detecting that AC has residual voltage simultaneously, starts locking transverter in short-term immediately, examines
Survey both sides transverter residual voltage size.By residual voltage size of relatively respectively standing, actual earth fault hair is judged
Raw side.
Claims (8)
- A kind of 1. voltage source converter fault detecting and positioning method, it is characterised in that：By detecting fault current, Compare bridge arm reactor current and current on line side size, according to bridge arm current direction and current on line side direction, calculate Difference stream size between the two, by relatively more each station difference stream size, judge that side occurs for actual earth fault.
- 2. a kind of voltage source converter fault detecting and positioning method as described in right 1, it is characterised in that：When Can not by differential current computing method judge be out of order side when, if detecting that AC has residual voltage simultaneously, just Under the conditions of locking transverter in short-term, transverter residual voltage size is detected, by the way that relatively respectively station residual voltage is big It is small, judge that side occurs for actual earth fault.
- A kind of 3. voltage source converter fault detecting and positioning method as described in right 1, it is characterised in that：Meter Calculate the difference stream size between bridge arm reactor current and current on line side, threshold value △ I of the difference stream more than settingset, also, More than the stabilization delay △ t of setting1It is judged as failure side；Threshold value △ I of the difference stream less than settingsetIt is judged as non-event Hinder side.
- A kind of 4. voltage source converter fault detecting and positioning method as claimed in claim 3, it is characterised in that： The fault detecting and positioning method is carried out under the conditions of not locking transverter, wherein △ t1Span is 0~5s.
- 5. a kind of voltage source converter fault detecting and positioning method as described in right 1, it is characterised in that：Institute Fault detecting and positioning method is stated, suitable for the following neutral grounding mode of AC system：1) isolated neutral；2) Neutral Grounding through Resistance in Electrical；3) three kinds of modes of neutral by arc extinction coil grounding；Wherein, transverter topology can be half-bridge structure, full bridge structure, either class full bridge structure or half-bridge The mixing bridge arm structure of class full-bridge, or full-bridge is added to add the mixing bridge arm structure of class full-bridge.
- A kind of 6. voltage source converter fault detecting and positioning method as described in right 1, it is characterised in that：Institute Fault detecting and positioning method is stated to be used to handle transverter one end generation singlephase earth fault, double earthfault, three Phase earth fault.
- A kind of 7. voltage source converter fault detecting and positioning method as described in right 2, it is characterised in that：When When transverter topological structure is full bridge structure, pass through fully closed lock or half closedown mode in short-term, it is ensured that zero sequence is grounded Electric current will not be delivered to offside current conversion station by DC side；When transverter topological structure is half-bridge structure, pass through Closedown mode in short-term, unilateral transverter output residual voltage size is detected, when voltage is more than the threshold value △ of setting Uset, and more than certain stabilization delay △ t2, then it is judged as failure side, being judged as non-faulting side in the case of other.
- A kind of 8. voltage source converter fault detect alignment system, it is characterised in that：System includes current detecting Unit, zero sequence voltage detection unit, logic comparing unit and fault detect positioning unit；The current detecting unit detection current on line side and bridge arm current size；The zero sequence voltage detection unit detects AC residual voltage size；The logic comparing unit flows size by calculating the difference of current on line side and bridge arm current between the two, when Difference stream is more than given threshold △ Iset, and more than certain stabilization delay △ t1, then it is judged as failure side；Difference stream is small In given numerical value △ IsetThen it is judged as non-faulting side；The logic comparing unit is then in the case where above-mentioned more each station difference flows big submethod failure conditions, in the locking change of current Under the conditions of device, result that above zero sequence voltage detection unit is obtained is input to logic comparing unit, residual voltage More than the threshold value △ U of settingset, and more than certain stabilization delay △ t2, then it is judged as failure side, other sides are Non-faulting side；The fault detect positioning unit combines above-mentioned comparative result, first detection difference stream size failure judgement side, If side of being out of order can not be judged by differential current computing method, start locking transverter in short-term, detection exchange immediately Side residual voltage size, by residual voltage size of relatively respectively standing, judge that side occurs for actual earth fault.
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| CN201610296443.9A CN107346003B (en) | 2016-05-05 | 2016-05-05 | Voltage source converter fault detection and positioning method and system |
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| CN201610296443.9A CN107346003B (en) | 2016-05-05 | 2016-05-05 | Voltage source converter fault detection and positioning method and system |
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| CN107346003B CN107346003B (en) | 2020-09-08 |
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Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN108490369A (en) * | 2018-03-07 | 2018-09-04 | 西南交通大学 | HVDC transmission system transverter fast fault locating method |
| CN109142974A (en) * | 2018-08-31 | 2019-01-04 | 天津大学 | A kind of alternating current circuit one-end fault ranging method suitable for flexible direct current feed-in |
| CN109617026A (en) * | 2018-10-12 | 2019-04-12 | 天津大学 | A kind of DC grid converter station ground fault ultra- high speed protection method |
| CN114217171A (en) * | 2021-12-15 | 2022-03-22 | 广东电网有限责任公司 | Single-phase earth fault detection method for converter valve side of flexible direct current transmission system |
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| CN103887772A (en) * | 2013-09-11 | 2014-06-25 | 南京南瑞继保电气有限公司 | Flexible DC power transmission grounding measurement device and protection method |
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| CN101540501A (en) * | 2009-04-17 | 2009-09-23 | 中国南方电网有限责任公司超高压输电公司 | Ground electrode circuit protective system and device of high-voltage DC transmission system |
| JP2013121223A (en) * | 2011-12-07 | 2013-06-17 | Hitachi Ltd | Power converter |
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Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN108490369A (en) * | 2018-03-07 | 2018-09-04 | 西南交通大学 | HVDC transmission system transverter fast fault locating method |
| CN109142974A (en) * | 2018-08-31 | 2019-01-04 | 天津大学 | A kind of alternating current circuit one-end fault ranging method suitable for flexible direct current feed-in |
| CN109617026A (en) * | 2018-10-12 | 2019-04-12 | 天津大学 | A kind of DC grid converter station ground fault ultra- high speed protection method |
| CN114217171A (en) * | 2021-12-15 | 2022-03-22 | 广东电网有限责任公司 | Single-phase earth fault detection method for converter valve side of flexible direct current transmission system |
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| CN107346003B (en) | 2020-09-08 |
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