CN108199356A - DC power transmission line ultra- high speed protection method based on wavefront information - Google Patents

DC power transmission line ultra- high speed protection method based on wavefront information Download PDF

Info

Publication number
CN108199356A
CN108199356A CN201711487275.2A CN201711487275A CN108199356A CN 108199356 A CN108199356 A CN 108199356A CN 201711487275 A CN201711487275 A CN 201711487275A CN 108199356 A CN108199356 A CN 108199356A
Authority
CN
China
Prior art keywords
protection
transmission line
failure
power transmission
high speed
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.)
Granted
Application number
CN201711487275.2A
Other languages
Chinese (zh)
Other versions
CN108199356B (en
Inventor
宋国兵
张晨浩
王莉
樊占峰
李佳朋
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Xuji Group Co Ltd
Xian Jiaotong University
Xuchang XJ Software Technology Co Ltd
Original Assignee
Xuji Group Co Ltd
Xian Jiaotong University
Xuchang XJ Software Technology Co Ltd
Priority date (The priority date 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 date listed.)
Filing date
Publication date
Application filed by Xuji Group Co Ltd, Xian Jiaotong University, Xuchang XJ Software Technology Co Ltd filed Critical Xuji Group Co Ltd
Priority to CN201711487275.2A priority Critical patent/CN108199356B/en
Publication of CN108199356A publication Critical patent/CN108199356A/en
Application granted granted Critical
Publication of CN108199356B publication Critical patent/CN108199356B/en
Active legal-status Critical Current
Anticipated expiration legal-status Critical

Links

Classifications

    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02H—EMERGENCY PROTECTIVE CIRCUIT ARRANGEMENTS
    • H02H7/00—Emergency protective circuit arrangements specially adapted for specific types of electric machines or apparatus or for sectionalised protection of cable or line systems, and effecting automatic switching in the event of an undesired change from normal working conditions
    • H02H7/26—Sectionalised protection of cable or line systems, e.g. for disconnecting a section on which a short-circuit, earth fault, or arc discharge has occured
    • H02H7/265—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
    • 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
    • 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

Landscapes

  • Physics & Mathematics (AREA)
  • General Physics & Mathematics (AREA)
  • Engineering & Computer Science (AREA)
  • Theoretical Computer Science (AREA)
  • Emergency Protection Circuit Devices (AREA)
  • Locating Faults (AREA)

Abstract

The present invention discloses a kind of DC power transmission line ultra- high speed protection method based on wavefront information, includes the following steps：1) circuit head end protection installation place electric current is measured, calculates electric current zero _exit；2) traveling wave leading edge portion is identified, so as to which starting protection differentiates failure；3) after protection starts, failure sampled data is calculated, is determined as troubles inside the sample space and external area error.The present invention has high resistance to transition resistance ability and discriminating direction ability while wavefront fault distance information is extracted；With rapidity, reliability, protection domain is long and without high sampling rate requirement.

Description

DC power transmission line ultra- high speed protection method based on wavefront information
Technical field
The invention belongs to field of relay protection in power, more particularly to a kind of DC power transmission line based on wavefront information Ultra- high speed protection method.
Background technology
Direct current transportation has many advantages, such as high-transmission capacity, flexible power control and remote transmission, at present electric system Customary DC and flexible direct current are widely used in transmission of electricity.After DC line breaks down, trouble duration is shorter More be conducive to the raising of Transmission Lines power and the enhancing of power system transient stability, Zhangbei County's flexible DC power transmission to after Electric protection Outlet time proposes the requirement of 3ms, and the ultra- high speed protection based on wink at the beginning of failure becomes the emphasis studied at present.
Traveling-wave protection has the characteristics that quick acting, it is mainly using the traveling characteristics of fault traveling wave (when wave velocity, propagation Between relationship from fault distance) and the wave property (fault traveling wave slope, mutation) of traveling wave provide the different protection schemes of circuit.But Currently with the protection philosophies of fault traveling wave traveling characteristics, there are sample rate requirement is high, mathematical theory defect problem；Utilize failure There is malfunction of being struck by lightning in the protection philosophy of traveling wave wave property, and its sensitivity is by transition resistance, fault distance, sampling The influence of frequency.
Invention content
The purpose of the present invention is to provide a kind of DC power transmission line ultra- high speed protection method based on wavefront information, with solution Certainly above-mentioned technical problem.The forward position of fault traveling wave is known as wavefront, and wavefront includes abundant fault message；The present invention improves existing row The performance of wave protection, meets requirement of the DC line to relay protection.The present invention is counted first by theory analysis and emulation And circuit parameter frequency dependent characteristic and failure broadband properties when, fault traveling wave wavefront shape variation degree has with fault distance It closes, transition resistance only influences wavefront amplitude, do not influence the conclusion of wavefront variation degree.Thus construction related coefficient reflection two is different Similarity degree between fault distance traveling wave wavefront, realizes the differentiation of failure.The related coefficient calculating of wavefront is needed to traveling wave wavefront T Data are sampled in time, it is therefore desirable to traveling wave wavefront arrival moment is identified, zero mould electric current is calculated using ratio method Front and rear moment relative variation realizes the identification of traveling wave leading edge portion (wavefront).
What guard method proposed by the present invention utilized is the fault message that traveling wave forward position includes, and is eliminated using related coefficient The phase of the influence of fault traveling wave wavefront amplitude variation, only simple per unit variation between faults traveling wave wavefront and related benchmark Like degree, there is high resistance to transition resistance ability and discriminating direction ability while extracting wavefront fault distance information.With quick Property, reliability, and without high sampling rate requirement.
In order to achieve the above objectives, the present invention adopts the following technical scheme that：
DC power transmission line ultra- high speed protection method based on wavefront information, includes the following steps：
1) circuit head end protection installation place electric current is measured, calculates electric current zero _exit；
2) traveling wave leading edge portion is identified, so as to which starting protection differentiates failure；
3) after protection starts, failure sampled data is calculated, is determined as troubles inside the sample space and external area error.
Further, in step 1)：DC power transmission line circuit head end protection installation place electric current is measured, is calculated as follows out Electric current zero _exit；
Wherein, Ip、In、I0、I1Anode, cathodal current and zero mould calculated, the mould that respectively protection installation place measures Electric current.
Further, in step 2)：Traveling wave leading edge portion is identified by formula (2), so as to which starting protection sentences failure Not；
Wherein, i0(n)、i0(n+1)、i0(n+2)、i0(n+3) it is zero mould current sampling data, kset、k1set、k2set、k3setFor Setting valve meets：
K in formula1Moment ratio, K before and after zero mould electric current when being worked normally for circuitrel1、Krel2、Krel3For safety factor, three A value is sequentially increased.
Further, Krel1、Krel2、Krel31.1,1.3,1.5 are taken respectively.
Further, in step 3)：After protection starts, failure sampled data is calculated by formula (4)：
Data length used by T differentiates for protection in formula, TsFor sampling step length, i0set(j) nearby occur for circuit midpoint Sampled value in zero mould current traveling wave wavefront T time section of metallicity failure；i0(j) it is zero mould current sampling data of protection；
When meeting ρ >=ρset, it is determined as troubles inside the sample space, otherwise protection act is external area error, wherein：
ρ≥ρset=Krelρ1 (5)
ρ in formula1For the phase calculated during failure by formula (4) on the outside of DC line end DC filter, smoothing reactor Relationship number, KrelFor safety factor.
Further, KrelFor safety factor, 1.1 are taken.
Relative to the prior art, the invention has the advantages that：
What the present invention utilized is the fault message that traveling wave forward position includes, and fault traveling wave wavefront width is eliminated using related coefficient It is worth the influence of variation, only the simple similarity degree that per unit changes between faults traveling wave wavefront and related benchmark, extracts wave There is high resistance to transition resistance ability and discriminating direction ability while prior fault range information.This method has rapidity, reliably Property (be not struck by lightning, operate disturbing influence), and without high sampling rate requirement.
Description of the drawings
Fig. 1 is transmission line of electricity resistance per unit length, inductance and capacitance modulus frequency characteristic；Wherein Fig. 1 (a) for mould resistance with The situation of change of frequency；Wherein Fig. 1 (b) is situation of change of the mould inductance with frequency；Wherein Fig. 1 (c) is mould capacitance with frequency Situation of change；
Fig. 2 is transmission line of electricity propagation coefficient frequency characteristic；Wherein Fig. 2 (a) is attenuation coefficient frequency characteristic；Wherein Fig. 2 (b) For phase coefficient frequency characteristic；
Fig. 3 is the frequency characteristic of transmission line of electricity wave velocity；
Fig. 4 is fault current characteristics；Wherein Fig. 4 (a) is failure electrode current；Wherein Fig. 4 (b) is zero mould electric current of failure；
Fig. 5 is the relationship of fault traveling wave wavefront and fault distance；
Fig. 6 is the relationship of traveling wave wavefront and transition resistance；
Fig. 7 is DC transmission system structure chart；
Fig. 8 is the ultra- high speed protection method flow diagram based on wavefront information.
Specific embodiment
The invention will be further described below in conjunction with the accompanying drawings：
The present invention analyzes transmission line parameter frequency dependent characteristic, has obtained what meter and each parameter of circuit were influenced with frequency variation Line propagation coefficient, wave velocity characteristic.Fig. 1 is transmission line of electricity resistance per unit length, inductance and capacitance modulus frequency characteristic；Fig. 2 For transmission line of electricity propagation coefficient frequency characteristic；Fig. 3 is the frequency characteristic of transmission line of electricity wave velocity.It can be seen that：Different frequency The speed that signal is propagated on transmission line of electricity is different, and the attenuation in communication process is also different.Each parameter of transmission line of electricity is in low frequency Existing difference during with high frequency causes the propagation characteristic difference of different frequency signals in the line.
Based on conclusions, the broadband properties of combination failure point traveling wave analyze the fault message that fault traveling wave includes.Figure 4 be fault current characteristics, and Fig. 5 is the relationship of fault traveling wave wavefront and fault distance；Fig. 6 is the pass of traveling wave wavefront and transition resistance System.And have to draw a conclusion：
1) fault traveling wave wavefront shape variation degree is related with fault distance.
2) transition resistance only influences wavefront amplitude, does not influence wavefront variation degree.
It please refers to Fig.1 to shown in Fig. 8, the present invention proposes a kind of DC power transmission line ultra- high speed protection based on wavefront information Method includes the following steps：
1) DC power transmission line circuit head end protection installation place electric current is measured, electric current zero _exit is calculated as follows out；
Wherein, Ip、In、I0、I1Anode, cathodal current and zero mould calculated, the mould that respectively protection installation place measures Electric current.
2) by formula (2) identification traveling wave leading edge portion (wavefront), so as to which starting protection differentiates failure；Meet formula (2) otherwise starting protection is protected and is not started；
Wherein, i0(n)、i0(n+1)、i0(n+2)、i0(n+3) it is zero mould current sampling data, kset、k1set、k2set、k3setFor Setting valve meets：
K in formula1Moment ratio, K before and after zero mould electric current when being worked normally for circuitrel1、Krel2、Krel3It, for safety factor Three values is asked to be sequentially increased, the present invention takes 1.1,1.3,1.5 respectively.
Lead to front and rear moment ratio infinity problem for zero mould current zero-crossing point, setting calculates threshold ksetEliminate zero passage Point influences.
3) after protection starts, failure sampled data is calculated by formula (4)：
Data length used by T differentiates for protection in formula, TsFor sampling step length, i0set(j) nearby occur for circuit midpoint Sampled value in zero mould current traveling wave wavefront T time section of metallicity failure is related coefficient calculating benchmark；i0(j) it is protection Zero mould current sampling data.
When meeting ρ >=ρset, it is determined as troubles inside the sample space, otherwise protection act is external area error, wherein：
ρ≥ρset=Krelρ1 (5)
ρ in formula1For the phase calculated during failure by formula (4) on the outside of DC line end DC filter, smoothing reactor Relationship number, KrelFor safety factor, the present invention takes 1.1.
Simulating, verifying：
Fig. 7 is DC transmission system structure chart.The present invention is right by taking the wide ± 800kV extra high voltage direct current transmission lines of cloud as an example Ultra- high speed protection method based on wavefront information carries out simulating, verifying, sample frequency 20kHz.Related coefficient benchmark is AC line Road is away from sampled value in the zero mould current traveling wave wavefront 1.5ms periods of metallicity monopole failure at head end 800km, ρsetIt is 0.9319, k1It is 1, ksetIt is 8.0 × 10-4kA。
Table 1, table 2, table 3, table 4 protect result when circuit different distance, transition resistance failure is set forth.F in table2、f3 For failure on the outside of line end DC filter, smoothing reactor, f8It is struck by lightning and disturbs for DC line, N is sampled point serial number.
As can be seen that during DC line fault, correct start is protected.Under protection setting setting valve, non-straight Flow Line event Barrier protection is failure to actuate；Error protection range is about away between circuit head end 200km-1400km on DC line.Protection can be correct It distinguishes DC line fault and lightning stroke disturbs.Table 5 provides different faults apart from lower metallicity failure and 500 Ω transition resistance failures Related coefficient relative change rate.With the increase of distance between failure and related benchmark failure, what transition resistance was brought becomes relatively Rate becomes larger, but both less than 2%, because protection philosophy proposed by the present invention is not influenced substantially by transition resistance.
In conclusion the protection philosophy proposed is effective.
1 circuit different distance failure related coefficient (0 Ω transition resistances) of table
2 circuit different distance failure related coefficient (100 Ω transition resistances) of table
3 circuit different distance failure related coefficient (300 Ω transition resistances) of table
4 circuit different distance failure related coefficient (500 Ω transition resistances) of table
5 different faults of table are apart from lower metallicity failure and 500 Ω transition resistance failure related coefficient relative change rates

Claims (6)

1. the DC power transmission line ultra- high speed protection method based on wavefront information, which is characterized in that include the following steps：
1) circuit head end protection installation place electric current is measured, calculates electric current zero _exit；
2) traveling wave leading edge portion is identified, so as to which starting protection differentiates failure；
3) after protection starts, failure sampled data is calculated, is determined as troubles inside the sample space and external area error.
2. the DC power transmission line ultra- high speed protection method according to claim 1 based on wavefront information, which is characterized in that In step 1)：DC power transmission line circuit head end protection installation place electric current is measured, electric current zero _exit is calculated as follows out；
Wherein, Ip、In、I0、I1Anode, cathodal current and zero mould calculated, the mould electric current that respectively protection installation place measures.
3. the DC power transmission line ultra- high speed protection method according to claim 1 based on wavefront information, which is characterized in that In step 2)：Traveling wave leading edge portion is identified by formula (2), so as to which starting protection differentiates failure；
Wherein, i0(n)、i0(n+1)、i0(n+2)、i0(n+3) it is zero mould current sampling data, kset、k1set、k2set、k3setTo adjust Value meets：
K in formula1Moment ratio, K before and after zero mould electric current when being worked normally for circuitrel1、Krel2、Krel3For safety factor, three values It is sequentially increased.
4. the DC power transmission line ultra- high speed protection method according to claim 3 based on wavefront information, which is characterized in that Krel1、Krel2、Krel31.1,1.3,1.5 are taken respectively.
5. the DC power transmission line ultra- high speed protection method according to claim 1 based on wavefront information, which is characterized in that In step 3)：After protection starts, failure sampled data is calculated by formula (4)：
Data length used by T differentiates for protection in formula, TsFor sampling step length, i0set(j) metal nearby occurs for circuit midpoint Sampled value in property zero mould current traveling wave wavefront T time section of failure；i0(j) it is zero mould current sampling data of protection；
When meeting ρ >=ρset, it is determined as troubles inside the sample space, otherwise protection act is external area error, wherein：
ρ≥ρset=Krelρ1 (5)
ρ in formula1For the phase relation calculated during failure by formula (4) on the outside of DC line end DC filter, smoothing reactor Number, KrelFor safety factor.
6. the DC power transmission line ultra- high speed protection method according to claim 5 based on wavefront information, which is characterized in that KrelFor safety factor, 1.1 are taken.
CN201711487275.2A 2017-12-29 2017-12-29 Wave-front information-based DC transmission line ultra-high speed protection method Active CN108199356B (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
CN201711487275.2A CN108199356B (en) 2017-12-29 2017-12-29 Wave-front information-based DC transmission line ultra-high speed protection method

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
CN201711487275.2A CN108199356B (en) 2017-12-29 2017-12-29 Wave-front information-based DC transmission line ultra-high speed protection method

Publications (2)

Publication Number Publication Date
CN108199356A true CN108199356A (en) 2018-06-22
CN108199356B CN108199356B (en) 2020-11-10

Family

ID=62587142

Family Applications (1)

Application Number Title Priority Date Filing Date
CN201711487275.2A Active CN108199356B (en) 2017-12-29 2017-12-29 Wave-front information-based DC transmission line ultra-high speed protection method

Country Status (1)

Country Link
CN (1) CN108199356B (en)

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN109193578A (en) * 2018-08-13 2019-01-11 西安交通大学 DC power transmission line fast protection method based on wavefront Generalized Logistic Function Fitting
CN110133433A (en) * 2019-03-27 2019-08-16 国网浙江省电力有限公司电力科学研究院 A kind of DC distribution net fault disturbance discrimination method based on mutation integrated product
CN110470952A (en) * 2019-08-19 2019-11-19 西安交通大学 The fault detection method of DC distribution net
CN111157843A (en) * 2020-01-06 2020-05-15 长沙理工大学 Power distribution network line selection method based on time-frequency domain traveling wave information

Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN102255291A (en) * 2011-07-04 2011-11-23 昆明理工大学 Simulation after test method for pilot protection of alternating-current transmission line based on Bergeron model
CN103618300A (en) * 2013-12-09 2014-03-05 中国南方电网有限责任公司超高压输电公司检修试验中心 High-sensitivity traveling-wave protection method for high-voltage direct current power transmission line
CN103633629A (en) * 2013-11-11 2014-03-12 同济大学 High-voltage direct current power transmission line protection method based on wavelet transformation and energy spectrum analysis
US20150233976A1 (en) * 2012-10-03 2015-08-20 Abb Technology Ltd Method for sensing a fault in a power system based on travelling wave currents
CN104977502A (en) * 2015-06-11 2015-10-14 昆明理工大学 Extra-high-voltage DC power transmission line area internal and external fault identification method
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

Patent Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN102255291A (en) * 2011-07-04 2011-11-23 昆明理工大学 Simulation after test method for pilot protection of alternating-current transmission line based on Bergeron model
US20150233976A1 (en) * 2012-10-03 2015-08-20 Abb Technology Ltd Method for sensing a fault in a power system based on travelling wave currents
CN103633629A (en) * 2013-11-11 2014-03-12 同济大学 High-voltage direct current power transmission line protection method based on wavelet transformation and energy spectrum analysis
CN103618300A (en) * 2013-12-09 2014-03-05 中国南方电网有限责任公司超高压输电公司检修试验中心 High-sensitivity traveling-wave protection method for high-voltage direct current power transmission line
CN104977502A (en) * 2015-06-11 2015-10-14 昆明理工大学 Extra-high-voltage DC power transmission line area internal and external fault identification method
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

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
徐海洋等: "行波波头的参数识别方法在高压直流输电系统中的应用", 《西安交通大学学报》 *

Cited By (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN109193578A (en) * 2018-08-13 2019-01-11 西安交通大学 DC power transmission line fast protection method based on wavefront Generalized Logistic Function Fitting
CN110133433A (en) * 2019-03-27 2019-08-16 国网浙江省电力有限公司电力科学研究院 A kind of DC distribution net fault disturbance discrimination method based on mutation integrated product
CN110133433B (en) * 2019-03-27 2021-07-06 国网浙江省电力有限公司电力科学研究院 Direct-current power distribution network fault disturbance identification method based on mutation integral product
CN110470952A (en) * 2019-08-19 2019-11-19 西安交通大学 The fault detection method of DC distribution net
CN111157843A (en) * 2020-01-06 2020-05-15 长沙理工大学 Power distribution network line selection method based on time-frequency domain traveling wave information
CN111157843B (en) * 2020-01-06 2022-04-12 长沙理工大学 Power distribution network line selection method based on time-frequency domain traveling wave information

Also Published As

Publication number Publication date
CN108199356B (en) 2020-11-10

Similar Documents

Publication Publication Date Title
CN108199356A (en) DC power transmission line ultra- high speed protection method based on wavefront information
CN102255293B (en) Single-ended electrical quantity full-line quick-action protection method for recognizing faults inside and outside high-voltage direct-current transmission line region
CN108054736B (en) A kind of multiterminal flexible direct current power grid DC line protection method based on voltage pole wave
CN107979075B (en) A kind of multiterminal flexible direct current power grid DC line Non-unit protection method
CN105098738B (en) A kind of HVDC transmission line longitudinal protection method based on S-transformation
CN105790239A (en) High-voltage direct-current power transmission line non-unit protection method based on S transformation
CN103675602B (en) A kind of transmission line lightning stroke flashover and the method for discrimination of non-flashover
CN107390046A (en) A kind of high voltage direct current transmission line fault type judgement method
CN109888744A (en) A kind of guard method of HVDC transmission line
CN103323741B (en) A kind of D molded line cable mixed line fault section compared based on false voltage initial row wave amplitude for strong fault sentences method for distinguishing
CN112881855B (en) Lightning stroke interference identification method for high-voltage direct-current transmission line based on generalized S transformation
CN109283428A (en) A kind of feeder line exit single-phase earthing transient based protection method based on the transformation of zero-sequence component higher difference
CN108872791B (en) The single-phase high-impedance of low resistance grounding power distribution network identifies and guard method
CN103760462B (en) A kind of current temporary state amount classified analysis on major constituents direction protection method of band SSSC transmission line of electricity
CN106019007A (en) DC line lightning stroke flashover property recognition method based on multi-measuring-point electrode current traveling wave
CN111641196A (en) High-voltage direct-current line pilot protection method based on branch current characteristics
CN103675536B (en) A kind of thunderbolt interference identification method utilizing instantaneous power and fitting a straight line
CN110336254A (en) A kind of hvdc transmission line guard method based on jump-value of current ratio
CN108963976B (en) Transformer excitation flow recognition method based on difference current polar coordinate system phase space reconstruction technique
CN109193578A (en) DC power transmission line fast protection method based on wavefront Generalized Logistic Function Fitting
CN115792507B (en) Multiple lightning stroke distinguishing method and system based on monotonicity of short-time window slope
CN115575772B (en) Transient zero modulus identification method for lightning shielding failure and counterattack of power transmission line
CN115616330B (en) Power transmission line multiple lightning identification method and system based on waveform similarity
CN106405194A (en) Lightning current waveform restoration method based on transient electric quantity of two ends of conductor
CN110336257A (en) A kind of anti-lightning strike and abnormal protection of direct current supply line method and system several greatly

Legal Events

Date Code Title Description
PB01 Publication
PB01 Publication
SE01 Entry into force of request for substantive examination
SE01 Entry into force of request for substantive examination
GR01 Patent grant
GR01 Patent grant