CN107482598B - Traveling-wave protection method suitable for LCC-HVDC inverter side alternating current circuit - Google Patents
Traveling-wave protection method suitable for LCC-HVDC inverter side alternating current circuit Download PDFInfo
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- CN107482598B CN107482598B CN201710719135.7A CN201710719135A CN107482598B CN 107482598 B CN107482598 B CN 107482598B CN 201710719135 A CN201710719135 A CN 201710719135A CN 107482598 B CN107482598 B CN 107482598B
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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
- H02H7/265—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 making use of travelling wave theory
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- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02H—EMERGENCY PROTECTIVE CIRCUIT ARRANGEMENTS
- H02H1/00—Details of emergency protective circuit arrangements
- H02H1/0007—Details of emergency protective circuit arrangements concerning the detecting means
-
- 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
- H02H7/28—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 meshed systems
Abstract
The invention discloses a kind of traveling-wave protection methods suitable for LCC-HVDC inverter side alternating current circuit, according to three-phase current traveling wave sampled value, starting protection；Nearly Inverter Station side and remote Inverter Station side protection location intercept T respectively1And T2Length data window；Phase-model transformation is carried out to the three-phase current traveling wave sampled value in data window, obtains 1,2,3,0 mould current traveling wave；Respectively at nearly Inverter Station side and remote Inverter Station side protection location 1 mould and 2 mould current traveling waves carry out integral operation, and intercourse current traveling wave integrated value；According to obtained current traveling wave integrated value, fault section is judged；Combination failure section identifies the amplitude size of 1,2,3, the 0 initial wave head of mould current traveling wave, to determine failure phase.High reliablity of the present invention, quick action have important meaning to alternating current-direct current combined hybrid system safety and stability level is improved.
Description
Technical field
The present invention relates to a kind of traveling-wave protection methods suitable for LCC-HVDC inverter side alternating current circuit.
Background technique
With the continuous expansion of electric system scale, large capacity alternating current-direct current combined hybrid system is largely built, transmission distance length,
Transmission line capability is big, power transmission efficiency is high.But due to the special construction of current source type D.C. high voltage transmission (LCC-HVDC) Inverter Station and
Control strategy operates normally the influence vulnerable to inverter side alternating current circuit failure and easily leads to and change if failure cannot be cut off rapidly
Phase failure problem results even in direct current locking.And traveling-wave protection quick action, tolerance transition resistance ability are strong, can react
Various fault types.It such as configures traveling-wave protection to the main protection of inverter side alternating current circuit, is beneficial to guarantee direct current system
It operates normally.
But it has been installed in parallel high-capacity reactive compensation device and filter on Inverter Station ac bus, for high frequency row
Wave signal (> 1kHz) is similar to be directly grounded a little.Therefore, alternating current circuit is difficult to close to the side protective device installation place of Inverter Station
Detect voltage traveling wave signal, and the catadioptric of current traveling wave signal is also different from pure AC system.Alternating current circuit is far from inversion
The voltage and current traveling wave for the side protective device installation place stood can be detected normally, and its catadioptric feature exchanges system with pure
It unites identical.Accordingly, traditional guard method needed using route both end voltage and current traveling wave, as Amplitude Comparison traveling wave is protected
Maintaining method, Polarity comparision formula traveling-wave protection method, traveling-wave differential protection method etc., are no longer desirable for inverter side alternating current circuit.
Though current polarity comparison expression traveling-wave protection method can still be applied, it only utilizes the polarity information of initial current wave head, and protection can
It is poor by property.
Summary of the invention
The present invention is no longer applicable in solve the problems, such as traditional traveling-wave protection method or poor reliability, proposes a kind of be applicable in
Traveling-wave protection method in LCC-HVDC inverter side alternating current circuit, the present invention have fully considered the special row in inverter side alternating current circuit
Setback reflection characteristic in cog region or external area error, has preferable applicability, while believing using current traveling wave in a period of time
Number integral, the high reliablity of protection.
To achieve the goals above, the present invention adopts the following technical scheme:
A kind of traveling-wave protection method suitable for LCC-HVDC inverter side alternating current circuit, comprising the following steps:
(1) it according to three-phase current traveling wave sampled value, detects whether to meet protection start-up criterion, protects entry condition when meeting
When, starting protection；
(2) after protection starting, nearly Inverter Station side and remote Inverter Station side protection location intercept T respectively1And T2Length data window；
(3) phase-model transformation is carried out to the three-phase current traveling wave sampled value in data window, obtains 1,2,3,0 mould current traveling wave,
To at nearly Inverter Station side and remote Inverter Station side protection location 1 mould and 2 mould current traveling waves carry out integral operation, and intercourse electricity
Popular wave integrated value；
(4) according to obtained current traveling wave integrated value, judge fault section.Combination failure section, identification 1,2,3,0 mould electricity
The amplitude size of the popular initial wave head of wave, to determine failure phase.
In the step (1), start-up criterion is protected are as follows:
N is number of sampling points, and i (t) is t moment current sampling data, I after high-pass filteringthrWith Δ IthrRespectively door
Threshold value.Wherein, criterion 1 or criterion 2 can have a satisfaction, and protection can start.
In the step (2), after protection starting, nearly Inverter Station side and remote Inverter Station side protection location intercept T respectively1And T2
Length data window, T1>=1ms, T2>=0.2ms, wherein data window should be comprising the front portion data of protection Startup time, to protect
Card covering initial current wavefront data.
In the step (3), phase-model transformation algorithm are as follows:
Wherein, ia、ib、icRespectively a, b, c phase current traveling wave, i1、i2、i3、i0Respectively 1,2,3,0 mould current traveling wave.
In the step (3), current traveling wave integral algorithm at nearly inverter side protection location are as follows:
Wherein iL1And iL2Respectively 1 mould and 2 mould current traveling waves, t1And T1Respectively data window initial time and data window are long
Degree, m take >=2 integer, and sgn (x) is to take sign function, IL1,intAnd IL2,intRespectively 1 mould and 2 mould current traveling waves integral.
In the step (3), current traveling wave integral algorithm at remote inverter side protection location are as follows:
Wherein iR1And iR2Respectively 1 mould and 2 mould current traveling waves, t2And T2Respectively data window initial time and data window are long
Degree, m take >=2 integer, and sgn (x) is to take sign function, IR1,intAnd IR2,intRespectively 1 mould and 2 mould current traveling waves integral.
In the step (3), both ends protection location is communicated via channel, and channel suggests taking strong interference immunity, is transmitted
Fireballing optical cable.1 mould of local terminal and 2 mould current traveling wave integrated values are sent to opposite end protection list via channel by both ends protection location
Member, and receive 1 mould of opposite end and 2 mould current traveling wave integrated values.
In the step (4), after receiving end protection location receives other end protection location current traveling wave integrated value, use
Following criterion:
Wherein ILR,thrFor threshold value, numerical value generally takes >=0.02.If criterion 1 or criterion 2 are invalid, then it is determined as
External area error, and latch-up protection；If criterion 1 or criterion 2 have one can set up, then it is determined as troubles inside the sample space, carries out failure and mutually sentence
It is disconnected.
In the step (4), when being determined as troubles inside the sample space, the amplitude of 1,2,3, the 0 initial wave head of mould current traveling wave is identified:
Such as only have a modulus amplitude equal to 0 and the modulus is not 0 mould, is then singlephase earth fault；As the amplitude of a non-zero modulus is
Twice of other two non-zero modulus amplitude, and 0 mould amplitude is 0, then it is earth-free for phase-to phase fault；As a non-zero modulus is obviously big
In other two non-zero modulus, and 0 mould amplitude is greater than 0, then is determined as two-phase grounding fault；As 1,2,3 mould current amplitudes are all larger than
0, and 0 mould amplitude is 0, then is determined as three-phase shortcircuit.
Compared with prior art, the invention has the benefit that
(1) present invention only requires that can differentiate area's internal and external fault using both ends current traveling wave signal, can preferably be suitable for
LCC-HVDC inverter side alternating current circuit efficiently solves the traveling-wave protection that tradition needs to utilize both-end voltage, current traveling wave signal
Principle has been difficult to applicable problem；
(2) conventional current Polarity comparision formula traveling-wave protection method is merely with initial current wavefront polarity, though it can still fit
With, but its reliability is low.And it is the integral of current traveling wave signal in one piece of data window that the present invention, which utilizes, it is with higher reliable
Property；
(3) it is used as a kind of traveling-wave protection method, the present invention is resistant to different transition resistances, different fault type, no
Same fault initial angle；
(4) in guard method proposed by the present invention, both ends protection location does not need to transmit a large amount of sampled datas, it is only necessary to transmit
Current traveling wave integral result, communication channel data transmission pressure is small, and guard method is easily achieved；
(5) protection philosophy quick action proposed by the present invention, can be improved AC-DC hybrid power grid to a certain extent
Stability；
(6) fault phase-selecting method based on each modulus of current traveling wave is, it can be achieved that selectivity tripping.
Detailed description of the invention
The Figure of description for constituting a part of the invention is used to provide further understanding of the present invention, and of the invention shows
Examples and descriptions thereof are used to explain the present invention for meaning property, does not constitute improper limitations of the present invention.
Fig. 1 is traveling-wave protection method flow diagram of the invention；
Fig. 2 is the alternating current-direct current mixed connection network in the embodiment of the present invention；
Fig. 3 is Inverter Station ac bus large capacity filter and reactive power compensator in the embodiment of the present invention；
Protection location current traveling wave each modulus in both ends when Fig. 4 (a), Fig. 4 (b) are typical troubles inside the sample space in the embodiment of the present invention
Waveform；
Protection location current traveling wave each modulus in both ends when Fig. 5 (a), Fig. 5 (b) are typical external area error in the embodiment of the present invention
Waveform；
Specific embodiment:
The invention will be further described with embodiment with reference to the accompanying drawing.
It is noted that following detailed description is all illustrative, it is intended to provide further instruction to the present invention.Unless another
It indicates, all technical and scientific terms used herein has usual with general technical staff of the technical field of the invention
The identical meanings of understanding.
It should be noted that term used herein above is merely to describe specific embodiment, and be not intended to restricted root
According to exemplary embodiments of the present invention.As used herein, unless the context clearly indicates otherwise, otherwise singular
Also it is intended to include plural form, additionally, it should be understood that, when in the present specification using term "comprising" and/or " packet
Include " when, indicate existing characteristics, step, operation, device, component and/or their combination.
As background technique is introduced, traditional traveling-wave protection method exists in the prior art and is no longer applicable in or poor reliability
Deficiency, in order to solve technical problem as above, the invention proposes one kind be based on current traveling wave integral form longitudinal protection method.
The present invention has fully considered the special traveling wave catadioptric characteristic in inverter side alternating current circuit, has preferable applicability；Benefit of the invention
With the integral of current traveling wave signal in a period of time, the high reliablity of protection；The present invention proposes a kind of based on initial simultaneously
The fault phase-selecting method of current traveling wave wave head amplitude.
Fig. 2 is typical AC-DC hybrid power grid structure chart, including ± 800kV LCC-HVDC system and inverter side 500kV are handed over
Streaming system.Fig. 3 is the large capacity filter and reactive power compensator installed on LCC-HVDC inverter side ac bus.The present embodiment
Specific steps are as shown in Figure 1:
(1) protection starting.
For the effective acquisition for guaranteeing travelling wave signal, sample frequency is set as 1MHz.According to three-phase current traveling wave sampled value,
It detects whether to meet protection start-up criterion:
N is number of sampling points, and value is set as 5；I (t) is t moment current sampling data, I after high-pass filteringthrAnd Δ
IthrRespectively threshold value, value are disposed as 0.5kA.Wherein, criterion 1 or criterion 2 can have a satisfaction.
(2) data intercept window.
After protection starting, R1 and R2 protection location intercepts T respectively1And T2Length data window, and T1=1ms, T2=0.2ms.
Wherein, R1 protection location data window should include the data of 0.2ms length before local terminal protection Startup time, R2 protection location data
Window should include the data of 0.05ms length before local terminal protection Startup time.
(3) phase-model transformation.
Phase-model transformation algorithm are as follows:
Wherein, ia、ib、icRespectively a, b, c phase current traveling wave, i1、i2、i3、i0Respectively 1,2,3,0 mould current traveling wave.
R1 and each current traveling wave modulus of R2 protection location when failure at F in the area Tu4Wei, R1 when failure at F1 outside the area Tu5Wei
With each current traveling wave modulus of R2 protection location.
(4) 1 mould and 2 mould current traveling waves integral are calculated.
Current traveling wave integral algorithm at R1 protection location are as follows:
Wherein iL1And iL2Respectively 1 mould and 2 mould current traveling waves, t1And T1Respectively data window initial time and data window are long
Degree, it is to take sign function, I that m value, which takes 2, sgn (x),L1,intAnd IL2,intRespectively 1 mould and 2 mould current traveling waves integral.
Current traveling wave integral algorithm at R2 protection location are as follows:
Wherein iR1And iR2Respectively 1 mould and 2 mould current traveling waves, t2And T2Respectively data window initial time and data window are long
Degree, it is to take sign function, I that m value, which takes 2, sgn (x),R1,intAnd IR2,intRespectively 1 mould and 2 mould current traveling waves integral.
Fig. 4 (a), Fig. 4 (b) are R1 and each current traveling wave modulus of R2 protection location, R1 protection location 1 when failure at F in area
Mould and 2 mould current traveling wave integral results are respectively 21.2530kA2And 22.2123kA2, 1 mould of R2 protection location and 2 mould current traveling waves
Integral result is respectively 3.1016kA2And 2.9687kA2。
Fig. 5 (a), Fig. 5 (b) are R1 and each current traveling wave modulus of R2 protection location, R1 protection location 1 when failure at F1 outside area
Mould and 2 mould current traveling wave integral results are respectively 5.9604kA2And 6.3859kA2, 1 mould of R2 protection location and 2 mould current traveling waves are long-pending
Dividing result is respectively -2.0595kA2With -2.1838kA2。
(5) both ends protection location exchanging electric current traveling wave integrated value.
As pilot protection, strong interference immunity is chosen, the fast optical cable of transmission speed exchanges information.R1 protection location is via light
1 mould of local terminal and 2 mould current traveling wave integrated values are sent to R2 protection location by cable, and receive 1 mould of R2 protection location and 2 mould current traveling waves
Integrated value.1 mould of local terminal and 2 mould current traveling wave integrated values are sent to R1 protection location via optical cable by R2 protection location, and receive R1
1 mould of protection location and 2 mould current traveling wave integrated values.
(6) fault section differentiates.
After R1 and R2 protection location receives opposite end protection location current traveling wave integrated value, it is all made of following criterion:
Wherein ILR,thrFor threshold value, numerical value takes 0.02.
If criterion 1 or criterion 2 are invalid, then external area error, and latch-up protection are determined as；As criterion 1 or criterion 2 have one
It is a to set up, then it is determined as troubles inside the sample space, and enter in next step.
For troubles inside the sample space in Fig. 4 (a), Fig. 4 (b), criterion 1 and criterion 2 are set up in formula (10), protect correct decision
For troubles inside the sample space.For external area error in Fig. 5 (a), Fig. 5 (b), criterion 1 and criterion 2 are invalid in formula (10), and protection is just
Really it is determined as external area error.
(7) failure mutually differentiates.
When (6) step is judged as troubles inside the sample space, then the amplitude of 1,2,3, the 0 initial wave head of mould current traveling wave is identified, such as table 1
It is shown: to be then singlephase earth fault if an only modulus amplitude is equal to 0 and the modulus is not 0 mould；Such as a non-zero modulus
Amplitude is twice of other two non-zero modulus amplitude, and 0 mould amplitude is 0, then earth-free for phase-to phase fault；Such as a non-zero modulus
Significantly greater than other two non-zero modulus, and 0 mould amplitude is greater than 0, then is determined as two-phase grounding fault；Such as 1,2,3 mould current amplitudes
Being all larger than 0, and 0 mould amplitude is 0, then is determined as three-phase shortcircuit.Visual actual conditions sequential trip after phase is out of order in differentiation.
For troubles inside the sample space in Fig. 4 (a), Fig. 4 (b): detecting 1,2,3,0 mould current traveling wave primary wave at R1 protection location
The amplitude of head is respectively 1.3345kA, 1.3410kA, 0kA, 0.6228kA, is identified as AG failure；It is detected at R2 protection location
Amplitude to 1,2,3, the 0 initial wave head of mould current traveling wave is respectively 0.5454kA, 0.5390kA, 0kA, 0.1350kA, is identified
For AG failure.
1 Fault Phase Selection criterion of table
The foregoing is only a preferred embodiment of the present invention, is not intended to restrict the invention, for the skill of this field
For art personnel, the invention may be variously modified and varied.All within the spirits and principles of the present invention, made any to repair
Change, equivalent replacement, improvement etc., should all be included in the protection scope of the present invention.
Above-mentioned, although the foregoing specific embodiments of the present invention is described with reference to the accompanying drawings, not protects model to the present invention
The limitation enclosed, those skilled in the art should understand that, based on the technical solutions of the present invention, those skilled in the art are not
Need to make the creative labor the various modifications or changes that can be made still within protection scope of the present invention.
Claims (3)
1. a kind of traveling-wave protection method suitable for LCC-HVDC inverter side alternating current circuit, it is characterized in that: the following steps are included:
(1) it according to three-phase current traveling wave sampled value, detects whether to meet protection start-up criterion, when meeting protection entry condition,
Starting protection；
(2) after protection starting, nearly Inverter Station side and remote Inverter Station side protection location intercept T respectively1And T2Length data window；
(3) phase-model transformation is carried out to the three-phase current traveling wave sampled value in data window, 1,2,3,0 mould current traveling wave is obtained, to close
1 mould and 2 mould current traveling waves at Inverter Station side and remote Inverter Station side protection location carry out integral operation, and intercourse electric current row
Wave integrated value；
(4) according to obtained current traveling wave integrated value, judge fault section, combination failure section identifies 1,2,3,0 mould electric current row
The amplitude size of the initial wave head of wave, to determine failure phase；
In the step (4), after receiving end protection location receives other end protection location current traveling wave integrated value, use is following
Criterion:
Wherein ILR,thrFor threshold value, numerical value takes >=0.02；IL1,intAnd IL2,intRespectively close 1 mould of inverter side and 2 mould electric current rows
Wave integral, IR1,intAnd IR2,intRespectively remote 1 mould of inverter side and 2 mould current traveling waves integral；If criterion 1 or criterion 2 are invalid,
Then it is determined as external area error, and latch-up protection；If criterion 1 or criterion 2 have one can set up, then it is determined as troubles inside the sample space, carries out
Failure mutually judges；
In the step (4), for troubles inside the sample space, the amplitude of 1,2,3, the 0 initial wave head of mould current traveling wave is identified: such as only one
Modulus amplitude is equal to 0 and the modulus is not 0 mould, then is singlephase earth fault；If the amplitude of a non-zero modulus is that other two is non-
Twice of 0 modulus amplitude, and 0 mould amplitude is 0, then it is earth-free for phase-to phase fault；As a non-zero modulus is significantly greater than other two
Non-zero modulus, and 0 mould amplitude is greater than 0, then is determined as two-phase grounding fault；As 1,2,3 mould current amplitudes are all larger than 0, and 0 mould width
Value is 0, then is determined as three-phase shortcircuit.
2. a kind of traveling-wave protection method suitable for LCC-HVDC inverter side alternating current circuit as described in claim 1, feature
It is: in the step (3), current traveling wave integral algorithm at nearly inverter side protection location are as follows:
Wherein iL1And iL2Respectively 1 mould and 2 mould current traveling waves, t1And T1Respectively data window initial time and data window length, m
>=2 integer is taken, sgn (x) is to take sign function, IL1,intAnd IL2,intRespectively 1 mould and 2 mould current traveling waves integral.
3. a kind of traveling-wave protection method suitable for LCC-HVDC inverter side alternating current circuit as described in claim 1, feature
It is: in the step (3), current traveling wave integral algorithm at remote inverter side protection location are as follows:
Wherein iR1And iR2Respectively 1 mould and 2 mould current traveling waves, t2And T2Respectively data window initial time and data window length, m
>=2 integer is taken, sgn (x) is to take sign function, IR1,intAnd IR2,intRespectively 1 mould and 2 mould current traveling waves integral.
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| CN110957710B (en) * | 2019-12-25 | 2021-10-15 | 青岛科技大学 | Traveling wave protection method for hybrid multi-terminal direct current transmission line |
| CN111224386B (en) * | 2020-01-13 | 2022-05-17 | 国网河北省电力有限公司经济技术研究院 | Pilot protection method, pilot protection system and terminal equipment |
| CN114089104B (en) * | 2021-11-12 | 2022-12-09 | 西安交通大学 | Fault direction judging method and system based on line boundary line side voltage |
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