CN109638796A - A kind of long range HVDC transmission line differential protecting method - Google Patents
A kind of long range HVDC transmission line differential protecting method Download PDFInfo
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- CN109638796A CN109638796A CN201910055551.0A CN201910055551A CN109638796A CN 109638796 A CN109638796 A CN 109638796A CN 201910055551 A CN201910055551 A CN 201910055551A CN 109638796 A CN109638796 A CN 109638796A
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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
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- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02J—CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
- H02J3/00—Circuit arrangements for ac mains or ac distribution networks
- H02J3/36—Arrangements for transfer of electric power between ac networks via a high-tension dc link
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- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
- Y02E60/00—Enabling technologies; Technologies with a potential or indirect contribution to GHG emissions mitigation
- Y02E60/60—Arrangements for transfer of electric power between AC networks or generators via a high voltage DC link [HVCD]
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- Emergency Protection Circuit Devices (AREA)
Abstract
The present invention relates to a kind of long range HVDC transmission line differential protecting methods, comprising the following steps: (1) is decoupled to obtain the voltage and current Aerial mode component and ground mold component of route two sides to the collected route both end voltage current sampling data of voltage transformer and current transformer of route two sides converter station outlet；(2) the line mould spill current and ground mould spill current of reference point are obtained according to Bei Ruilong equivalent model；(3) operating criterion of the line mould spill current construction current differential protection of direct current electric transmission line of reference point is utilized；(4) using at reference point the ratio of mould spill current and line mould spill current construction failure selects pole criterion.
Description
Technical field
The present invention relates to protecting electrical power system control fields, and in particular to one kind is suitable for long range high-voltage dc transmission electric wire
Road current differential protection method.
Background technique
With the rapid development of power electronic technique, HVDC Transmission Technology embodies on remote, bulk power transmission
Advantage not available for many ac transmissions, HVDC Transmission Technology are quickly grown, and domestic DC transmission engineering is also stepped up.
DC power transmission line is the highest part of failure rate in entire DC transmission engineering, therefore the relay protection skill of DC power transmission line
Art is most important.Actual DC power transmission engineering needs often using current differential protection as the back-up protection of transmission line of electricity at present
The influence of the factors such as external area error out-of-balance current is escaped, by a longer time delay to guarantee current differential protection
Selectivity.
It, can be by calculating line using distributed parameter model in order to improve the performance of current differential protection of direct current electric transmission line
Capacitance current during difference current at the reference point of road eliminates line fault transient state influences, to improve current differential guarantor
The action performance of shield.Meanwhile transmission line parameter not only has distribution character and has frequency dependent characteristic, causes in long range direct current
Traveling wave dispersion phenomenon on transmission line of electricity is obvious, which limits the further of current differential protection of direct current electric transmission line performance
It is promoted.Therefore, by designing a kind of DC power transmission line differential protection side for taking into account line parameter circuit value distribution character and frequency dependent characteristic
Method can be such that its quick-action, sensitivity and reliability is more obviously improved.
Summary of the invention
For the problem that current current differential protection of direct current electric transmission line acting characteristic is poor, the present invention proposes that one kind can
The method for current differential protection of direct current electric transmission line of fast and reliable movement.Technical solution is as follows:
A kind of long range HVDC transmission line differential protecting method, if the both ends of transmission line of electricity be the side J and the side K, with
It is reference point at the r of route midpoint, comprising the following steps:
(1) to the collected route both end voltage electricity of the voltage transformer and current transformer of route two sides converter station outlet
Flow sampled value uJP、uJN、iJP、iJN、uKP、uKN、iKP、iKNIt is decoupled to obtain the voltage and current Aerial mode component u of route two sidesJ1、
uK1、iJ1、iK1With ground mold component uJ0、uK0、iJ0、iK0；
(2) according to Bei Ruilong equivalent model, the voltage and current Aerial mode component u of the side route J is utilizedJ1、iJ1Route is calculated
Line mould calculating current value i at the r of midpointsJr1, utilize the voltage and current Aerial mode component u of the side route KK1、iK1It is calculated in route
Line mould calculating current value i at point rsKr1, the line mould spill current i of reference point1diffFor the difference of the two:
i1diff=isjr1-iskr1
Similarly, the ground mould spill current i of reference point can be calculated0diff；
(3) operating criterion of the line mould spill current construction current differential protection of direct current electric transmission line of reference point is utilized:
In formula, isetFor the threshold value of current differential protection criterion, max { i1unbalanceIndicate various external area error situations
The maximum imbalance current value that the lower auspicious carina mould difference current of shellfish is likely to occur, krelFor safety factor；
(4) using at reference point the ratio of mould spill current and line mould spill current construction failure selects pole criterion:
M is threshold value in formula, considers to have guaranteed that all kinds of fault type differentiations have when certain allowance is set as 0.1
Enough sensitivitys.
Preferably, max { i1unbalanceValue when being the bipolar interpolar metallicity failure in proximal end outside protection zone differential protection go out
Existing out-of-balance current.krelTake 1.3~1.5.
Detailed description of the invention
Fig. 1 is HVDC transmission line schematic diagram.
Fig. 2 is the trend chart of line mould velocity of wave and ground mould velocity of wave.
Fig. 3 is all types of failure schematic diagrames, wherein (a) is two-wire line intereelectrode short-circuit failure, (b) is grounded for electrode line road
Failure (c) is anode circuit ground fault.
Specific embodiment
The Bei Ruilong equivalent model of transmission line of electricity is a kind of constant coefficient distributed parameter model, can preferably reflect that route is joined
Several distribution characters.Route can be calculated by the voltage and current measurement value at route both ends using Bei Ruilong equivalent model to refer to
Spill current at point constructs current differential protection criterion using the spill current, the acting characteristic of differential protection can be improved.But
DC power transmission line is often longer, and traveling wave dispersion phenomenon caused by the frequency dependent characteristic of DC power transmission line parameter be can not ignore, this
Shi Liyong Bei Ruilong equivalent model constructs DC power transmission line split pole current differential protection, by the frequency due to not considering line parameter circuit value
Become characteristic and influence computational accuracy, differential protection performance is caused to reduce.
Line mould spill current and ground mould spill current at route midpoint (reference point) r are calculated according to Bergeron model, utilizes ginseng
Operating criterion of the line mould spill current as difference current construction DC power transmission line differential protection at examination point r, followed by ginseng
The ratio of ground mould spill current and line mould spill current construction failure selects pole criterion at examination point r.
It the described method comprises the following steps:
As shown in Figure 1, the transmission line of electricity of HVDC transmission system is usually made of two anode, cathode transmission lines of electricity.
In figure, uJP、uJN、iJP、iJNRespectively converter station J exports the collected positive and negative anodes voltage and current of measuring device；uKP、uKN、iKP、
iKNRespectively converter station K exports the collected positive and negative anodes voltage and current of measuring device.There are electrical couplings between positive and negative anodes electrical quantity
It closes, decoupling matrices S shown in formula (1) can be used, positive and negative pole tension is decoupled.
Mutually independent Aerial mode component and ground mold component are obtained after decoupling.Wherein, Aerial mode component passes through positive and negative polarities route
Circuit is constituted, and ground mold component is flowed back by ground return circuit.Since Aerial mode component is not necessarily to by ground return circuit kelvin effect
Influence, the frequency of line parameter circuit value cashes as to be obviously lighter than ground mold component.Traveling wave dispersion caused by line parameter circuit value frequency dependent characteristic
Phenomenon is the main reason for reducing Bei Ruilong equivalent model computational accuracy.Fig. 2 gives under normal conditions, line mould velocity of wave and ground mould
The comparison of velocity of wave.As can be seen that line mould velocity of wave varying less with frequency, no matter in low-frequency range or high band, line mould velocity of wave
The light velocity being all closer in vacuum；And the frequency dependent characteristic of ground mould velocity of wave is then fairly obvious, only omits in the size of low-frequency range
Higher than the half of the light velocity in vacuum, with the raising of frequency, ground mould velocity of wave is gradually risen.It can be seen that for the line mould of route
Component, Bei Ruilong equivalent model still are able to guarantee very high computational accuracy.
(1) it is adopted using the voltage transformer and current transformer that the decoupling matrices S of formula (1) exports route two sides converter station
The route both end voltage current sampling data u collectedJP、uJN、iJP、iJN、uKP、uKN、iKP、iKNIt is decoupled to obtain route two sides
Voltage and current Aerial mode component uJ1、uK1、iJ1、iK1With ground mold component uJ0、uK0、iJ0、iK0。
(2) according to Bei Ruilong equivalent model, the voltage and current Aerial mode component u of the side route J is utilizedJ1、iJ1Route is calculated
Line mould calculating current value i at the r of midpointsJr1, utilize the voltage and current Aerial mode component u of the side route KK1、iK1It is calculated in route
Line mould calculating current value i at point rsKr1, the line mould spill current i of reference point1diffFor the difference of the two:
i1diff=isjr1-iskr1 (2)
Similarly, the ground mould spill current i of reference point can be calculated0diff。
(3) since the traveling wave dispersion phenomenon of DC power transmission line Aerial mode component is more slight, the meter of Bergeron model is utilized
Calculation precision is higher, utilizes the operating criterion of the line mould spill current construction current differential protection of direct current electric transmission line of reference point:
In formula, isetFor the threshold value of current differential protection criterion, max { i1unbalanceIndicate various external area error situations
(in general it is double to can use proximal end outside protection zone to the maximum imbalance current value that the lower auspicious carina mould difference current of shellfish is likely to occur for the value
The out-of-balance current that differential protection occurs when the interpolar metallicity failure of pole), krel1.3~1.5 are generally taken for safety factor.
(4) differential protection is made to lose its own using line mould spill current construction current differential protection of direct current electric transmission line
Natural failure select pole ability, in addition failure need to be set select pole criterion.Still consider to utilize the modulus spill current information at reference point r
Pole criterion is selected to construct failure.Because failure selects criterion movement in pole that should act after current differential protection movement, it is only necessary to realize
The judgement of fault category can suitably relax line parameter circuit value frequency and cash as the influence to Bei Ruilong equivalent model computational accuracy.If
Dispersion phenomenon caused by the frequency dependent characteristic of DC power transmission line parameter is not considered, then the ground mould spill current and line mould of reference point are poor
Electric current will meet following formula:
In formula, if0、if1It is the ground mold component and Aerial mode component of fault current respectively；ifP、ifNIt is positive route respectively and negative
The fault current of polar curve road injection fault point.
Analyze the modulus spill current of reference point and the relationship of fault type:
A) as shown in Fig. 3 (a), anode route and the fault current of anode circuit injection fault point have when bipolar interpolar failure
Following relationship:
Formula (5) are substituted into formula (4), the modulus spill current of reference point and the relationship of fault current when can obtain bipolar interpolar failure
Are as follows:
The ratio of the two is 0.
B) as shown in Fig. 3 (b), anode route and the fault current of anode circuit injection fault point have when plus earth failure
Following relationship:
Formula (7) are substituted into formula (4), the modulus spill current of reference point and the relationship of fault current when can obtain plus earth failure
Are as follows:
The ratio of the two is 1.
C) as shown in Fig. 3 (b), anode route and the fault current of anode circuit injection fault point have when cathode ground fault
Following relationship:
Formula (10) are substituted into formula (4), the modulus spill current of reference point and the pass of fault current when can obtain cathode ground fault
System are as follows:
The ratio of the two is -1.
Accordingly, can design using at reference point the ratio of mould spill current and line mould spill current construction failure selects pole to sentence
According to:
M is threshold value in formula, considers to have guaranteed that all kinds of fault type differentiations have when certain allowance is set as 0.1
Enough sensitivitys.After the current differential protection criterion movement of formula (3), i.e., fault type is judged using formula (9).
The present invention problem poor for current differential protection of direct current electric transmission line acting characteristic devises a kind of based on mould
The method for current differential protection of direct current electric transmission line of amount and its matched fault type judgment method.This method has fully considered defeated
The distribution character and frequency dependent characteristic of electric line parameter, by constructing electricity using the line mould spill current of Bergeron model calculating reference point
Differential Protection criteria is flowed, while the influence for eliminating capacitance current and traveling wave dispersion phenomenon are to spill current computational accuracy
It influences；In addition, failure selects pole criterion to ensure that the failure of the current differential protection based on modulus information selects pole ability.The present invention is thorough
Bottom eliminates the problem of Traditional DC transmission current differential protection needs long delay locking to escape out-of-balance current, improves electric current
Quick-action, sensitivity and the reliability of differential protection, and that the present disclosure applies equally to transmission distances is longer, traveling wave dispersion phenomenon compared with
For apparent (spy) HVDC transmission line.
Claims (3)
1. a kind of long range HVDC transmission line differential protecting method, if the both ends of transmission line of electricity are the side J and the side K, with line
It is reference point at the r of road midpoint, comprising the following steps:
(1) the collected route both end voltage electric current of voltage transformer and current transformer of route two sides converter station outlet is adopted
Sample value uJP、uJN、iJP、iJN、uKP、uKN、iKP、iKNIt is decoupled to obtain the voltage and current Aerial mode component u of route two sidesJ1、uK1、
iJ1、iK1With ground mold component uJ0、uK0、iJ0、iK0；
(2) according to Bei Ruilong equivalent model, the voltage and current Aerial mode component u of the side route J is utilizedJ1、iJ1Route midpoint r is calculated
The line mould calculating current value i at placesJr1, utilize the voltage and current Aerial mode component u of the side route KK1、iK1It is calculated at the r of route midpoint
Line mould calculating current value isKr1, the line mould spill current i of reference point1diffFor the difference of the two:
i1diff=isjr1-iskr1
Similarly, the ground mould spill current i of reference point can be calculated0diff；
(3) operating criterion of the line mould spill current construction current differential protection of direct current electric transmission line of reference point is utilized:
In formula, isetFor the threshold value of current differential protection criterion, max { i1unbalanceIndicate various external area errors in the case of shellfish it is auspicious
The maximum imbalance current value that carina mould difference current is likely to occur, krelFor safety factor；
(4) using at reference point the ratio of mould spill current and line mould spill current construction failure selects pole criterion:
M is threshold value in formula, considers to have guaranteed that all kinds of fault types differentiate have enough when certain allowance is set as 0.1
Sensitivity.
2. long range HVDC transmission line differential protecting method according to claim 1, which is characterized in that max
{i1unbalanceValue differential protection appearance when being the bipolar interpolar metallicity failure in the outer proximal end in protection zone out-of-balance current.
3. long range HVDC transmission line differential protecting method according to claim 1, which is characterized in that krelIt takes
1.3~1.5.
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| CN201910055551.0A CN109638796B (en) | 2019-01-22 | 2019-01-22 | Differential protection method for long-distance high-voltage direct-current transmission line |
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| CN201910055551.0A CN109638796B (en) | 2019-01-22 | 2019-01-22 | Differential protection method for long-distance high-voltage direct-current transmission line |
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Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN110568308A (en) * | 2019-07-19 | 2019-12-13 | 昆明理工大学 | Extra-high voltage direct current transmission line area internal and external fault identification method based on Bergeron line model |
| CN112202149A (en) * | 2020-06-23 | 2021-01-08 | 中国电力科学研究院有限公司 | Method and system for processing abnormal large number of direct-current transmission line protection based on voltage comparison method |
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| US7286963B2 (en) * | 2005-12-30 | 2007-10-23 | Abb Technology Ltd. | Method and device for fault location on three terminal power line |
| CN106300295A (en) * | 2016-09-07 | 2017-01-04 | 南京南瑞继保电气有限公司 | A kind of dual sensitivity Bei Ruilong differential protecting method of half-wavelength transmission line of alternation current |
| CN106711969A (en) * | 2017-01-17 | 2017-05-24 | 西安科技大学 | Pilot protection method for double ultrahigh voltage direct current transmission line based on modulus saltation |
| CN106849029A (en) * | 2017-02-13 | 2017-06-13 | 西安科技大学 | The bipolar multi-terminal direct current transmission system electric current modulus longitudinal differential protection method of parallel connection type |
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2019
- 2019-01-22 CN CN201910055551.0A patent/CN109638796B/en active Active
Patent Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US7286963B2 (en) * | 2005-12-30 | 2007-10-23 | Abb Technology Ltd. | Method and device for fault location on three terminal power line |
| CN106300295A (en) * | 2016-09-07 | 2017-01-04 | 南京南瑞继保电气有限公司 | A kind of dual sensitivity Bei Ruilong differential protecting method of half-wavelength transmission line of alternation current |
| CN106711969A (en) * | 2017-01-17 | 2017-05-24 | 西安科技大学 | Pilot protection method for double ultrahigh voltage direct current transmission line based on modulus saltation |
| CN106849029A (en) * | 2017-02-13 | 2017-06-13 | 西安科技大学 | The bipolar multi-terminal direct current transmission system electric current modulus longitudinal differential protection method of parallel connection type |
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN110568308A (en) * | 2019-07-19 | 2019-12-13 | 昆明理工大学 | Extra-high voltage direct current transmission line area internal and external fault identification method based on Bergeron line model |
| CN110568308B (en) * | 2019-07-19 | 2021-07-13 | 昆明理工大学 | Extra-high voltage direct current transmission line area internal and external fault identification method based on Bergeron line model |
| CN112202149A (en) * | 2020-06-23 | 2021-01-08 | 中国电力科学研究院有限公司 | Method and system for processing abnormal large number of direct-current transmission line protection based on voltage comparison method |
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