CN106443346A - Multi-fractal spectrum ultra-high voltage direct current line fault identification method based on filter branch current - Google Patents
Multi-fractal spectrum ultra-high voltage direct current line fault identification method based on filter branch current Download PDFInfo
- Publication number
- CN106443346A CN106443346A CN201610876810.2A CN201610876810A CN106443346A CN 106443346 A CN106443346 A CN 106443346A CN 201610876810 A CN201610876810 A CN 201610876810A CN 106443346 A CN106443346 A CN 106443346A
- Authority
- CN
- China
- Prior art keywords
- formula
- epsiv
- direct current
- current line
- quality
- 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.)
- Pending
Links
- 238000001228 spectrum Methods 0.000 title claims abstract description 14
- 238000000034 method Methods 0.000 title claims abstract description 9
- 230000005540 biological transmission Effects 0.000 claims description 17
- 238000005192 partition Methods 0.000 claims description 15
- 238000010276 construction Methods 0.000 claims description 3
- 238000005259 measurement Methods 0.000 abstract 1
- 238000005070 sampling Methods 0.000 abstract 1
- 238000004088 simulation Methods 0.000 description 4
- 230000007704 transition Effects 0.000 description 4
- 230000009471 action Effects 0.000 description 3
- 210000001367 artery Anatomy 0.000 description 3
- 238000009499 grossing Methods 0.000 description 3
- 210000003462 vein Anatomy 0.000 description 3
- 230000007257 malfunction Effects 0.000 description 2
- 230000004888 barrier function Effects 0.000 description 1
- 230000009286 beneficial effect Effects 0.000 description 1
- 230000008859 change Effects 0.000 description 1
- 230000001419 dependent effect Effects 0.000 description 1
- 238000001514 detection method Methods 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 238000005516 engineering process Methods 0.000 description 1
- 239000004744 fabric Substances 0.000 description 1
- 230000001681 protective effect Effects 0.000 description 1
- 230000004044 response Effects 0.000 description 1
- 230000001052 transient effect Effects 0.000 description 1
Classifications
-
- 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
- G01R31/08—Locating faults in cables, transmission lines, or networks
- G01R31/081—Locating faults in cables, transmission lines, or networks according to type of conductors
- G01R31/085—Locating faults in cables, transmission lines, or networks according to type of conductors in power transmission or distribution lines, e.g. overhead
-
- 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
- G01R31/08—Locating faults in cables, transmission lines, or networks
- G01R31/088—Aspects of digital computing
Landscapes
- Physics & Mathematics (AREA)
- General Physics & Mathematics (AREA)
- Engineering & Computer Science (AREA)
- Mathematical Physics (AREA)
- Theoretical Computer Science (AREA)
- Emergency Protection Circuit Devices (AREA)
Abstract
The invention relates to a multi-fractal spectrum ultra-high voltage direct current line fault identification method based on filter branch current and belongs to the technical field of direct current line protection. When a direct current line has a fault, a sampling frequency is 6.4kHz, and a filter branch measurement end is used for obtaining current data; and k (k>=2) squares of proper edges of [Epsilon] 1, [Epsilon] 2, ...[Epsilon] k are selected to over current i(t), so as to obtain the quality distribution probability pk ([Epsilon]) and the non-uniform degree index [delta][alpha], and finally faults inside and outside a direct current line area are identified according to that whether the non-uniform degree index [delta][alpha] is larger than a fixed value [delta][alpha]set or not. The invention generates time domain waveforms in case of faults inside and outside the direct current line area based on the multi-fractal spectrum, constructs protection criteria hereby, and achieves the stronger traveling wave protection transition-resisting resistance capability.
Description
Technical field
The present invention relates to a kind of based on filter branches electric current multifractal spectra UHVDC Transmission Lines fault recognition method,
Belong to DC line protection technical field.
Background technology
DC power transmission line distance, crosses over the circumstance complication in area, and the probability breaking down is big, and actual operating data shows
Showing, DC line fault accounts for the 50% of DC transmission system fault.But, Practical Project shows the positive positive motion of DC line protection
The protective rate only 50% made, has the DC line fault of nearly half by control system action, direct locking DC transmission system, incites somebody to action
Unnecessary direct current is caused to stop transport.DC line fault causes DC system locking, not only causes substantial amounts of load loss, and
And the impact to electrical network is very big, even can affect the stable operation of electrical network.The protection of direct current supply line that current China has put into operation
Main traveling-wave protection, differential low-voltage protection, longitudinal differential protection and under-voltage protection based on rate of change and variable quantity
Deng.It is analyzed discovery by action situation in engineering is actual for the traveling-wave protection：Traveling-wave protection with du/dt as core is often
High resistive fault (High impedance fault, HIF) can not be responded reliably, and as the longitudinal differential of high resistive fault detection
Protection is dependent on time delay to transient response during escaping fault in ac transmission system to ensure its not malfunction.Meanwhile, for avoiding power to adjust
Whole period not malfunction, adds again latching logic in SIMENS differential protection, so longitudinal differential protection outlet time delay is oversize, and can
Longitudinal differential protection can be caused usually not have back-up protection effect, in some instances it may even be possible to DC control system protection can be caused first to move
Make, cause unnecessary direct current locking accident.
Content of the invention
The technical problem to be solved in the present invention is to provide a kind of based on the extra-high straightening of filter branches electric current multifractal spectra
Flow Line fault recognition method, in order to solve the problems referred to above.
The technical scheme is that：A kind of based on filter branches electric current multifractal spectra UHVDC Transmission Lines fault
Recognition methods, when DC line breaks down, sample frequency is 6.4kHz, utilizes filter branches measuring end to obtain electric current number
According to；Choose the individual suitable length of side of k (k >=2) and be respectively ε1,ε2,……εkSquare go cover electric current i (t), obtain quality and divide
Cloth Probability pk(ε) it with degree of irregularity index Δ α, whether is more than definite value Δ α finally according to degree of irregularity index Δ αsetKnow
Other DC line internal fault external fault.
Concretely comprise the following steps：
The first step, utilize filter branches measuring end obtain electric current i (t)；
Second step, calculating distributive probatility of quality pk(ε) it is：
In formula (1), ik(ε) length of side is used to be respectively ε1,ε2,……εkSquare go cover measuring end current signal i
(t), the quality of each box obtaining,Quality for all boxes；
3rd step, to distributive probatility of quality pk(ε) it is weighted summation with q power and obtain partition function χq(ε), partition letter
Number χq(ε) there is following relation with yardstick ε：
χq(ε)≡∑pk(ε)q(2)
Q is asked for, mono-initial value of q can be given in advance, different q is circulated, obtain partition letter according to formula (2)
Number χq(ε)；
4th step, to partition function χq(ε), after asking for the length of side with box length of side ε, further according to formula (3), broad sense can be tried to achieve
Dimension Dq；
5th step, obtaining performance figure τ (q) according to formula (4), its essence is exactly χq(ε) with ε on log-log coordinate curve
Slope；
τ (q)=(q-1) Dq(4)
6th step, can be obtained by scaling exponent α and there is the fractal dimension just as unusual degree α according to formula (5) and (6)
f(α)：
F (α)=q α-τ (q) (6)
7th step, calculating unevenness index are Δ α；
Δ α=αmax-αmin(7)
In formula (7), αminThe maximum subset of corresponding mass distribution probability, αmaxThe minimum subset of corresponding mass distribution probability；
8th step, construction based on multiple parting spectrum DC line district in, the identical criterion of external area error be：
If Δ α >=Δ αset, then it is troubles inside the sample space
If Δ α ＜ Δ αset, then it is external area error
In formula, Δ αsetFor definite value.
The invention has the beneficial effects as follows：Portray in DC line district, under external area error based on using multifractal spectra
Time domain waveform, and the Protection criteria constituting according to this are strong compared to the ability of the existing resistance to transition resistance of traveling-wave protection.
Brief description
Fig. 1 be cloud of the present invention wide ± the simulation model figure of 800kV extra-high voltage DC transmission system；
Fig. 2 is measuring end map of current under present invention distance rectification side 1300km line fault；
Fig. 3 is ln χ of the present inventionq(ε) graph of relation with ln ε；
Fig. 4 is the graph of relation of τ (q) of the present invention and q；
Fig. 5 is the graph of relation of α and f of the present invention (α)；
Fig. 6 is the distribution map of the unevenness index Δ α in the range of the present invention grows completely；
Fig. 7 is the distribution map of unevenness index Δ α under the various external area error of the present invention.
Detailed description of the invention
Below in conjunction with the accompanying drawings and detailed description of the invention, the invention will be further described.
A kind of based on filter branches electric current multifractal spectra UHVDC Transmission Lines fault recognition method, work as DC line
When breaking down, sample frequency is 6.4kHz, utilizes filter branches measuring end to obtain current data；Choose the individual conjunction of k (k >=2)
The suitable length of side is respectively ε1,ε2,……εkSquare go cover electric current i (t), obtain distributive probatility of quality pk(ε) and uneven
Whether level index Δ α, be more than definite value Δ α finally according to degree of irregularity index Δ αsetIdentify event inside and outside DC line district
Barrier.
Concretely comprise the following steps：
The first step, utilize filter branches measuring end obtain electric current i (t)；
Second step, calculating distributive probatility of quality pk(ε) it is：
In formula (1), ik(ε) length of side is used to be respectively ε1,ε2,……εkSquare go cover measuring end current signal i
(t), the quality of each box obtaining,Quality for all boxes；
3rd step, to distributive probatility of quality pk(ε) it is weighted summation with q power and obtain partition function χq(ε), partition letter
Number χq(ε) there is following relation with yardstick ε：
χq(ε)≡∑pk(ε)q(2)
Q is asked for, mono-initial value of q can be given in advance, different q is circulated, obtain partition letter according to formula (2)
Number χq(ε)；
4th step, to partition function χq(ε), after asking for the length of side with box length of side ε, further according to formula (3), broad sense can be tried to achieve
Dimension Dq；
5th step, obtaining performance figure τ (q) according to formula (4), its essence is exactly χq(ε) with ε on log-log coordinate curve
Slope；
τ (q)=(q-1) Dq(4)
6th step, can be obtained by scaling exponent α and there is the fractal dimension just as unusual degree α according to formula (5) and (6)
f(α)：
F (α)=q α-τ (q) (6)
7th step, calculating unevenness index are Δ α；
Δ α=αmax-αmin(7)
In formula (7), αminThe maximum subset of corresponding mass distribution probability, αmaxThe minimum subset of corresponding mass distribution probability；
8th step, construction based on multiple parting spectrum DC line district in, the identical criterion of external area error be：
If Δ α >=Δ αset, then it is troubles inside the sample space
If Δ α ＜ Δ αset, then it is external area error
In formula, Δ αsetFor definite value.
Embodiment 1：Set up as shown in Figure 1 using cloud wide ± 800kV extra-high voltage DC transmission system is as simulation model.
The AC reactive compensation capacity of rectification side and inverter side is respectively 3000 and 3040Mvar, and every pole convertor unit is by 2 12 arteries and veins
Rushing transverter to be composed in series, DC power transmission line total length is 1500km.Circuit both sides are equipped with the smoothing reactor of 400mH, direct current
Wave filter is 12/24/36 three-tuned filter, and rectification side ground electrode circuit total length is 109km, inverter side ground electrode circuit total length
For 80km.It is now assumed that positive pole circuit occurs earth fault away from M end 100km, transition resistance is 100 Ω.
Filter branches measuring end Q is utilized to obtain electric current i (t) according to step one；It is calculated according to step 2 and formula (1)
Distributive probatility of quality pk(ε)；It is calculated partition function χ according to step 3 and formula (2)q(ε)；Calculate according to step 4 and formula (4)
Obtain Generalized Dimension Dq；Obtain performance figure τ (q) according to step 5 and formula (4)；Just permissible according to step 6 and formula (5) and (6)
Obtain α and f (α)；Calculating unevenness index according to step 7 and formula (7) is Δ α=1.2782；According to step 8, it is known that Δ α
=1.2782 ＞ Δ αset, it is known that it is troubles inside the sample space.
Embodiment 2：Set up as shown in Figure 1 using cloud wide ± 800kV extra-high voltage DC transmission system is as simulation model.
The AC reactive compensation capacity of rectification side and inverter side is respectively 3000 and 3040Mvar, and every pole convertor unit is by 2 12 arteries and veins
Rushing transverter to be composed in series, DC power transmission line total length is 1500km.Circuit both sides are equipped with the smoothing reactor of 400mH, direct current
Wave filter is 12/24/36 three-tuned filter, and rectification side ground electrode circuit total length is 109km, inverter side ground electrode circuit total length
For 80km.It is now assumed that negative pole circuit occurs earth fault away from M end 1000km, transition resistance is 100 Ω.
Filter branches measuring end Q is utilized to obtain electric current i (t) according to step one；It is calculated according to step 2 and formula (1)
Distributive probatility of quality pk(ε)；It is calculated partition function χ according to step 3 and formula (2)q(ε)；Calculate according to step 4 and formula (4)
Obtain Generalized Dimension Dq；Obtain performance figure τ (q) according to step 5 and formula (4)；Just permissible according to step 6 and formula (5) and (6)
Obtain α and f (α)；Calculating unevenness index according to step 7 and formula (7) is Δ α=1.5176；According to step 8, it is known that Δ α
=1.5176 ＞ Δ αset, it is known that it is troubles inside the sample space.
Embodiment 3：Set up as shown in Figure 1 using cloud wide ± 800kV extra-high voltage DC transmission system is as simulation model.
The AC reactive compensation capacity of rectification side and inverter side is respectively 3000 and 3040Mvar, and every pole convertor unit is by 2 12 arteries and veins
Rushing transverter to be composed in series, DC power transmission line total length is 1500km.Circuit both sides are equipped with the smoothing reactor of 400mH, direct current
Wave filter is 12/24/36 three-tuned filter, and rectification side ground electrode circuit total length is 109km, inverter side ground electrode circuit total length
For 80km.It is now assumed that rectification side outlet occurs earth fault, transition resistance is 10 Ω.
Filter branches measuring end Q is utilized to obtain electric current i (t) according to step one；It is calculated according to step 2 and formula (1)
Distributive probatility of quality pk(ε)；It is calculated partition function χ according to step 3 and formula (2)q(ε)；Calculate according to step 4 and formula (4)
Obtain Generalized Dimension Dq；Obtain performance figure τ (q) according to step 5 and formula (4)；Just permissible according to step 6 and formula (5) and (6)
Obtain α and f (α)；Calculating unevenness index according to step 7 and formula (7) is Δ α=0.7586；According to step 8, it is known that Δ α
=0.7586 ＜ Δ αset, it is known that it is external area error.
It is explained in detail above in conjunction with the detailed description of the invention to the present invention for the accompanying drawing, but the present invention is not limited to above-mentioned
Embodiment, in the ken that those of ordinary skill in the art are possessed, can also be before without departing from present inventive concept
Put that various changes can be made.
Claims (2)
1. one kind based on filter branches electric current multifractal spectra UHVDC Transmission Lines fault recognition method, it is characterised in that：
When DC line breaks down, sample frequency is 6.4kHz, utilizes filter branches measuring end to obtain current data；Choose k
(k >=2) individual suitable length of side is respectively ε1,ε2,……εkSquare go cover electric current i (t), obtain distributive probatility of quality pk
(ε) it with degree of irregularity index Δ α, whether is more than definite value Δ α finally according to degree of irregularity index Δ αsetIdentify AC line
Road internal fault external fault.
2. according to claim 1 based on filter branches electric current multifractal spectra UHVDC Transmission Lines Fault Identification side
Method, it is characterised in that concretely comprise the following steps：
The first step, utilize filter branches measuring end obtain electric current i (t)；
Second step, calculating distributive probatility of quality pk(ε) it is：
In formula (1), ik(ε) length of side is used to be respectively ε1,ε2,……εkSquare go cover measuring end current signal i (t),
The quality of each box arriving,Quality for all boxes；
3rd step, to distributive probatility of quality pk(ε) it is weighted summation with q power and obtain partition function χq(ε), partition function χq
(ε) there is following relation with yardstick ε：
χq(ε)≡∑pk(ε)q(2)
Q is asked for, mono-initial value of q can be given in advance, different q is circulated, obtain partition function χ according to formula (2)q
(ε)；
4th step, to partition function χq(ε), after asking for the length of side with box length of side ε, further according to formula (3), Generalized Dimension can be tried to achieve
Dq；
5th step, obtaining performance figure τ (q) according to formula (4), its essence is exactly χq(ε) with oblique on log-log coordinate curve of ε
Rate；
τ (q)=(q-1) Dq(4)
6th step, can be obtained by scaling exponent α and there is the fractal dimension f just as unusual degree α according to formula (5) and (6)
(α)：
F (α)=q α-τ (q) (6) the 7th step, calculating unevenness index are Δ α；
Δ α=αmax-αmin(7)
In formula (7), αminThe maximum subset of corresponding mass distribution probability, αmaxThe minimum subset of corresponding mass distribution probability；8th
Step, construction based on multiple parting spectrum DC line district in, the identical criterion of external area error be：
If Δ α >=Δ αset, then it is troubles inside the sample space
If Δ α ＜ Δ αset, then it is external area error
In formula, Δ αsetFor definite value.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201610876810.2A CN106443346A (en) | 2016-10-08 | 2016-10-08 | Multi-fractal spectrum ultra-high voltage direct current line fault identification method based on filter branch current |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201610876810.2A CN106443346A (en) | 2016-10-08 | 2016-10-08 | Multi-fractal spectrum ultra-high voltage direct current line fault identification method based on filter branch current |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN106443346A true CN106443346A (en) | 2017-02-22 |
Family
ID=58172372
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN201610876810.2A Pending CN106443346A (en) | 2016-10-08 | 2016-10-08 | Multi-fractal spectrum ultra-high voltage direct current line fault identification method based on filter branch current |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN106443346A (en) |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN107121617A (en) * | 2017-03-09 | 2017-09-01 | 昆明理工大学 | A kind of direct current transmission line fault distance-finding method of use filter branches electric current and K k-nearest neighbors |
| CN111695089A (en) * | 2020-06-12 | 2020-09-22 | 国网四川省电力公司电力科学研究院 | Alternating current transmission line fault identification method based on multi-fractal spectrum |
Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102097791A (en) * | 2011-02-25 | 2011-06-15 | 昆明理工大学 | Fractal dimension-based ultrahigh voltage DC transmission line boundary element method |
| CN102508115A (en) * | 2011-10-27 | 2012-06-20 | 昆明理工大学 | Identification method for faults in and out of area of high voltage direct current (HVDC) transmission line based on multi-fractal spectrum |
| WO2012161606A1 (en) * | 2011-05-20 | 2012-11-29 | Атокс Канада Инкорпорэйтид | Method for predicting a seismic event |
| CN103683196A (en) * | 2013-07-24 | 2014-03-26 | 昆明理工大学 | A transformer excitation surge current discriminating method based on multi-factional spectrums |
| CN105701713A (en) * | 2016-03-06 | 2016-06-22 | 中国水利水电科学研究院 | Heterogeneity quantitative characterization method of soil pore distribution based on multi-fractal spectrum |
-
2016
- 2016-10-08 CN CN201610876810.2A patent/CN106443346A/en active Pending
Patent Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102097791A (en) * | 2011-02-25 | 2011-06-15 | 昆明理工大学 | Fractal dimension-based ultrahigh voltage DC transmission line boundary element method |
| WO2012161606A1 (en) * | 2011-05-20 | 2012-11-29 | Атокс Канада Инкорпорэйтид | Method for predicting a seismic event |
| CN102508115A (en) * | 2011-10-27 | 2012-06-20 | 昆明理工大学 | Identification method for faults in and out of area of high voltage direct current (HVDC) transmission line based on multi-fractal spectrum |
| CN103683196A (en) * | 2013-07-24 | 2014-03-26 | 昆明理工大学 | A transformer excitation surge current discriminating method based on multi-factional spectrums |
| CN105701713A (en) * | 2016-03-06 | 2016-06-22 | 中国水利水电科学研究院 | Heterogeneity quantitative characterization method of soil pore distribution based on multi-fractal spectrum |
Non-Patent Citations (1)
| Title |
|---|
| 田鑫萃: "《基于实测数据的特高压直流线路保护及接地极线路故障定位研究》", 《中国博士学位论文全文数据库 工程科技II辑》 * |
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN107121617A (en) * | 2017-03-09 | 2017-09-01 | 昆明理工大学 | A kind of direct current transmission line fault distance-finding method of use filter branches electric current and K k-nearest neighbors |
| CN107121617B (en) * | 2017-03-09 | 2019-09-27 | 昆明理工大学 | A kind of DC power transmission line k nearest neighbor distance measuring method using filter branches electric current |
| CN111695089A (en) * | 2020-06-12 | 2020-09-22 | 国网四川省电力公司电力科学研究院 | Alternating current transmission line fault identification method based on multi-fractal spectrum |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CN105548819B (en) | A kind of HVDC transmission line internal fault external fault recognition methods based on anti-traveling wave | |
| CN101546906B (en) | Method for fault line selection of electric distribution network by using S transformation energy relative entropy | |
| CN103346542B (en) | Based on the HVDC (High Voltage Direct Current) transmission line high resistance earthing fault recognition methods of distributed constant | |
| CN101964515B (en) | Method for converting boundary element by extra-high voltage direct current transmission line mode voltage S | |
| CN102590654B (en) | Element and method for discriminating fault electrode of DC transmission line | |
| CN103018627A (en) | Adaptive fault type fault line detection method for non-effectively earthed system | |
| Song et al. | A novel pilot protection principle for VSC-HVDC cable lines based on fault component current | |
| CN111856322B (en) | Direct-current distribution network bipolar short-circuit fault accurate positioning method and device based on MMC | |
| CN102508115B (en) | Identification method for faults in and out of area of high voltage direct current (HVDC) transmission line based on multi-fractal spectrum | |
| CN105207186A (en) | Distance protection method for power transmission line containing unified power flow controller | |
| CN103296650A (en) | Ultra-high-voltage transmission line relay protection method based on break variable differential coefficient matrix | |
| CN108258662A (en) | A kind of multiterminal flexible direct current distribution line transient protection method and device | |
| CN105606955B (en) | A kind of faulty line method of discrimination based on numerical differentiation and empirical mode decomposition | |
| CN104993466A (en) | Cascading failure fast dynamic simulation method suitable for alternating current-direct current power grid | |
| CN104135038B (en) | A kind of alternating current-direct current combined hybrid system unbalanced fault analytical method | |
| CN106443346A (en) | Multi-fractal spectrum ultra-high voltage direct current line fault identification method based on filter branch current | |
| CN106841924A (en) | Distribution network line insulated monitoring method based on parameter identification | |
| CN104868478A (en) | Method for starting dynamic partitioning scheme under condition of power grid emergency | |
| CN105044555A (en) | High voltage direct current power transmission line fault pole discrimination method by utilization of single pole electric quantity | |
| CN113504437A (en) | Single-phase earth fault interval identification method for neutral point small-resistance earth distribution network | |
| CN106505563A (en) | Grid-connected converter toughness appraisal procedure under a kind of electric network fault | |
| CN108808634A (en) | HVDC transmission line longitudinal protection method based on smoothing reactor voltage | |
| CN104078950B (en) | Ultra-high voltage transmission line relay protection method based on positive-sequence break variable differential coefficient matrix | |
| CN103901323A (en) | Fault line selection method with improved oscillator system | |
| CN104967116A (en) | Electromagnetic ring network ring opening method for multi-DC infeed receiving-end grid |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| C06 | Publication | ||
| PB01 | Publication | ||
| C10 | Entry into substantive examination | ||
| SE01 | Entry into force of request for substantive examination | ||
| RJ01 | Rejection of invention patent application after publication |
Application publication date: 20170222 |
|
| RJ01 | Rejection of invention patent application after publication |