CN109217267A - Multiterminal flexible direct current power grid longitudinal protection method and system based on current-limiting inductance polarity of voltage - Google Patents
Multiterminal flexible direct current power grid longitudinal protection method and system based on current-limiting inductance polarity of voltage Download PDFInfo
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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
- H02H7/261—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 involving signal transmission between at least two stations
- H02H7/263—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 involving signal transmission between at least two stations involving transmissions of measured values
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
- G01R31/00—Arrangements for testing electric properties; Arrangements for locating electric faults; Arrangements for electrical testing characterised by what is being tested not provided for elsewhere
- G01R31/08—Locating faults in cables, transmission lines, or networks
- G01R31/081—Locating faults in cables, transmission lines, or networks according to type of conductors
- G01R31/086—Locating faults in cables, transmission lines, or networks according to type of conductors in power transmission or distribution networks, i.e. with interconnected conductors
-
- 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
- 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
-
- 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
-
- 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
-
- 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]
-
- 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
- Y04—INFORMATION OR COMMUNICATION TECHNOLOGIES HAVING AN IMPACT ON OTHER TECHNOLOGY AREAS
- Y04S—SYSTEMS INTEGRATING TECHNOLOGIES RELATED TO POWER NETWORK OPERATION, COMMUNICATION OR INFORMATION TECHNOLOGIES FOR IMPROVING THE ELECTRICAL POWER GENERATION, TRANSMISSION, DISTRIBUTION, MANAGEMENT OR USAGE, i.e. SMART GRIDS
- Y04S10/00—Systems supporting electrical power generation, transmission or distribution
- Y04S10/50—Systems or methods supporting the power network operation or management, involving a certain degree of interaction with the load-side end user applications
- Y04S10/52—Outage or fault management, e.g. fault detection or location
Abstract
The invention discloses a kind of multiterminal flexible direct current power grid longitudinal protection method and system based on current-limiting inductance polarity of voltage, comprising: the voltage value of acquisition DC line both ends current-limiting inductance in real time；Voltage is handled using voltage gradient algorithm, and then detects whether faulty generation；After protection starting, the current-limiting inductance voltage in sampled data window is integrated, passes through the multilevel iudge current-limiting inductance polarity of voltage of integrated value S and setting threshold value；Route both ends current-limiting inductance polarity of voltage R is compared, if polarity is all positive, is judged as troubles inside the sample space, is otherwise judged as external area error.Protection philosophy and algorithm of the present invention are simple, do not need the mathematical tools such as Fast Fourier Transform (FFT), wavelet transformation and carry out frequency dividing or traveling wave capture, synchronous without two end data of route, it is easy to accomplish；Data window needed for Protection criteria is short, and does not need additional failure pole discriminating step, and quick-action is strong.
Description
Technical field
The present invention relates to DC grid line fault protection technical fields, more particularly to one kind to be based on current-limiting inductance voltage pole
The multiterminal flexible direct current power grid longitudinal protection method and system of property.
Background technique
Currently, the protection plan of conventional high-tension DC line has been used for reference in the protection of DC line in flexible DC transmission engineering
Slightly, using traveling-wave protection, differential under-voltage protection as the main protection of DC line.And the protection for multiterminal flexible direct current power grid,
Scholars are other than improving existing method, it is also proposed that some effective fast protection methods based on one-terminal data,
It such as acts on by the boundary of DC line endpoint current-limiting inductance, is differentiated in area by detection voltage change ratio, current changing rate etc.
Outer failure；It is identified using parameter and differentiates internal fault external fault；Utilize high frequency traveling wave energy analysis internal fault external fault etc..
Guard method quick action of the above based on one-terminal data, but due to only utilizing the list in very short time window
Look data up and down, protective value is serious by transition Resistance Influence, may selectively be unable to satisfy requirement.In contrast, vertical UNPROFOR
Shield can have absolute selectivity by the fault message establishing protective criterion at route both ends, however since signal transmission is led
The delay of cause is longer and generally as back-up protection.Current differential protection is made standby by conventional high-tension DC line, but the party
Method needs two end datas synchronous, and to escape the influence of fault transient process, the delay of current differential protection is up to hundreds of millis
Second, therefore be not easy to directly apply to multiterminal flexible direct current power grid.In this regard, proposing some new longitudinal protection methods both at home and abroad.
The prior art is using harmonic current caused by pulse width modulation (PWM), to be changed based on two power level voltage source types
The direct current system of stream device (VSC) proposes a kind of longitudinal protection method.However, the guard method is not suitable for forcing using nearest level
The direct current system based on modularization multi-level converter (MMC) closely modulated.
The prior art calculates separately route midpoint electric current using route both ends electrical quantity, and thus constructs differential criterion, is
Both ends direct current system based on VSC proposes a kind of current differential protection method.However, algorithm needed for the guard method is many and diverse, it is real
Existing difficulty is big.
The prior art proposes a kind of guard method based on traveling wave.When troubles inside the sample space, electricity that transmission line of electricity both ends detect
It is identical to flow polarity of traveling wave；And when external area error, current traveling wave polarity is opposite.When according to internal fault external fault, DC line both ends electricity
The polar relationship of popular wave proposes a kind of longitudinal protection method for multiterminal flexible direct current power grid DC line.However, fault resstance
When larger, traveling wave detector is particularly difficult, reduces the reliability of the guard method.
The prior art is using current-limiting inductance two sides voltage magnitude than judging forward and reverse failure.If route both ends all judge
For positive failure, then illustrate that troubles inside the sample space occurs；And route both ends differentiate result it is opposite when, then illustrate occur external area error.Into
It and is that DC line proposes a kind of longitudinal protection method.The guard method protects speed fast, however, it is necessary to which wavelet transformation extracts electricity
The special frequency band of pressure increases the realization difficulty of guard method.
It can be seen that the existing guard method about DC line in DC grid, respectively there are advantage and disadvantage, it is not easy to real still
It is existing, the method for quick action, sensitivity and high reliablity.
Summary of the invention
The present invention to solve the above-mentioned problems, proposes a kind of multiterminal flexible direct current power grid based on current-limiting inductance polarity of voltage
Longitudinal protection method and system, this method judge internal fault external fault according to the polarity of voltage of DC line both ends current-limiting inductance.With
Other DC line longitudinal protection methods are compared, and this method need to only acquire the polarity of voltage of DC line both ends current-limiting inductance, no
The mathematical tools such as wavelet transformation, Fast Fourier Transform (FFT) are needed, protection philosophy is simple, high reliablity, and quick action is easy to work
Cheng Shixian.
To achieve the goals above, the present invention adopts the following technical scheme:
A kind of multiterminal flexible direct current electricity based on current-limiting inductance polarity of voltage disclosed in one or more embodiments
Net longitudinal protection method, comprising:
(1) voltage in the current-limiting inductance of DC line both ends is acquired in real time；
(2) by voltage gradient algorithm, the whether faulty generation of collected voltage detecting DC line is utilized；
(3) if detecting failure, the voltage value in sampled data window is integrated, by comparing integrated value with set
The size relation of set threshold value, and then judge current-limiting inductance polarity of voltage；
(4) polarity of voltage of transmission line of electricity both ends current-limiting inductance is compared, if polarity is all positive, is judged as area
Otherwise internal fault is judged as external area error.
Further, by voltage gradient algorithm, using the whether faulty generation of collected voltage detecting, specifically:
|▽vL(k) | > Δ1；
Wherein, vL(k)、▽vL(k) be respectively k-th of sampled point in current-limiting inductance voltage value and voltage gradient value；Δ1
To start threshold value；K and j is sampled point.
Further, to the v in sampled data windowLIt is integrated, by comparing the size of integrated value and setting threshold value
Relationship, and then judge current-limiting inductance polarity of voltage, specifically:
To the voltage v in the current-limiting inductance of DC line both endsLIt is integrated respectively, if DC line one end current limliting is electric
Voltage integrating meter value in sense is greater than setting threshold value, then it is assumed that the polarity of voltage in the end current-limiting inductance is positive；Otherwise, which limits
Voltage jump polarity in galvanic electricity sense be it is non-just.
A kind of multiterminal flexible direct current electricity based on current-limiting inductance polarity of voltage disclosed in one or more embodiments
Net pilot protection system, including server, the server include memory, processor and storage on a memory and can locate
The computer program run on reason device, the processor are realized described in any of the above embodiments based on current limliting electricity when executing described program
Electrification presses polar multiterminal flexible direct current power grid longitudinal protection method.
A kind of computer readable storage medium disclosed in one or more embodiments, is stored thereon with computer journey
Sequence, the program execute the multiterminal flexible direct current described in any of the above embodiments based on current-limiting inductance polarity of voltage when being executed by processor
Power grid longitudinal protection method.
Compared with prior art, the beneficial effects of the present invention are:
(1) the guard method principle and algorithm are simple, do not need the mathematical tools pair such as Fast Fourier Transform (FFT), wavelet transformation
Failure amount carries out frequency dividing or traveling wave captures, synchronous without two side data of route, is easy to Project Realization；
(2) when troubles inside the sample space, the voltage jump amplitude of current-limiting inductance is larger, even if fault point transition resistance is larger, still
Reliable recognition can be carried out to failure.Therefore, mentioned protection scheme sensitivity with higher, reliability and absolute selection
Property；
(3) data window needed for Protection criteria is short, and quick-action is strong.Mentioned protection scheme does not need additional failure pole and differentiates step
Suddenly, the protection time used is further shortened.
Detailed description of the invention
The accompanying drawings constituting a part of this application is used to provide further understanding of the present application, and the application's shows
Meaning property embodiment and its explanation are not constituted an undue limitation on the present application for explaining the application.
Fig. 1 is Zhangbei County's DC engineering monopole wiring diagram；
Fig. 2 is the equivalent structure of single converter station after failure；
Current-limiting inductance voltage analysis figure when Fig. 3 is troubles inside the sample space；
Current-limiting inductance voltage analysis figure when Fig. 4 is external area error；
Fig. 5 is F1Locate v when plus earth failure12And v21Waveform；
Fig. 6 is F2Locate v when plus earth failure12And v21Waveform；
Fig. 7 is F2V when cathode ground fault occurs for placeLWaveform；
Fig. 8 is F2V when bipolar short trouble occurs for placeLWaveform；
Fig. 9 is F3V when bipolar short trouble occurs for placeLWaveform；
Figure 10 is F4V when bipolar short trouble occurs for placeLWaveform；
Figure 11 is F5V when bipolar short trouble occurs for placeLWaveform；
Figure 12 is F1Locate the traveling wave and communication signal transmissions process when failure in route I；
Figure 13 is the multiterminal flexible direct current power grid longitudinal protection method flow chart based on current-limiting inductance polarity of voltage.
Specific embodiment
It is noted that following detailed description is all illustrative, it is intended to provide further instruction to the application.Unless another
It indicates, all technical and scientific terms used herein has usual with the application person of an ordinary skill in the technical field
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 the illustrative embodiments of the application.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.
Embodiment one
In some embodiments, a kind of multiterminal flexible direct current power grid direct current based on current-limiting inductance polarity of voltage is disclosed
Method for pilot protection of circuit, as shown in figure 13, comprising the following steps:
(1) enabling route both ends is respectively the end M and N-terminal, acquires the voltage value v of DC line both ends current-limiting inductance in real timeLi(i
Indicate the positive p or cathode n) of DC line one end；
(2) using voltage gradient algorithm to vLiIt is handled, and then detects whether faulty generation；
Fault detection criterion and calculation expression are shown below,
|▽vL(k) | > Δ1 (1)
In formula, vL(k)、▽vL(k) be respectively k-th of sampled point in current-limiting inductance voltage value and voltage gradient value；Δ1
To start threshold value；K and j is sampled point.The setting principle for starting threshold is while escaping normal operating condition, it is ensured that area
Protection can reliably start when internal fault.
(3) after protection starting, the current-limiting inductance voltage in sampled data window is integrated, integrated value S and setting are passed through
The multilevel iudge current-limiting inductance polarity of voltage of threshold value；
(4) by fiber optic communication, route both ends current-limiting inductance polarity of voltage R is compared, if polarity is all positive,
It is judged as troubles inside the sample space, is otherwise judged as external area error.
Recognition principle of the invention are as follows:
1 accident analysis
1) system introduction
Currently the four end flexible direct current electricity power engineering of Zhangbei County in construction uses symmetrical dipolar configuration, and converter station is using half
Bridge MMC, transmission line of electricity use overhead line.Its protection system by current-limiting inductance combined with dc circuit breaker in the way of.Zhangbei County
The monopole wiring diagram of DC engineering is as shown in Figure 1, converter station 1,2,3,4 respectively indicates Kangbao County station, Fengning station, Zhangbei County station and Beijing
It stands.In Fig. 1, LBFor current-limiting inductance, vLIt is limited and flows inductive drop, the title and length of each DC line section has all been got the bid in figure
Out.
This patent introduces a kind of pilot protection scheme based on current-limiting inductance polarity of voltage using the engineering as case.
2) current-limiting inductance voltage
Fig. 2 show the equivalent structure of single converter station in multiterminal flexible direct current power grid.Since short circuit event occurs for DC side
After barrier, the influence of exchange side can be ignored when analyzing the transient voltage before converter station is latched, therefore, converter station can be equivalent to capacitor
With the tandem compound of inductance.In Fig. 2, F is fault point, LBFor the current-limiting inductance value of DC line endpoint, CS、LSThe respectively change of current
The equivalent capacitance value and equivalent inductance value of device, CS、LSIt can be obtained by following formula,
CS=6C0/n,LS=2LA/3 (3)
In formula, C0For submodule capacitance, n is submodule number contained by single bridge arm, LAFor bridge arm current-limiting inductance value.
After short trouble occurs for DC line, 0 mould and 1 mode voltage Sudden Changing Rate Δ v at the F of fault point0With Δ v1Such as following formula institute
Show,
Wherein, Z0And Z1Respectively 0 mould of DC line and 1 mould wave impedance, RgFor fault point transition resistance, VpFor anode
Voltage rating.
Decaying when being propagated in DC line in view of traveling wave, 0 mould of DC line endpoint, 1 mode voltage Sudden Changing Rate
WithAre as follows:
In above formula, α0And α1Respectively 0 mould of DC line and 1 mode attenuation coefficient, τ0And τ1Respectively 0 mould, 1 mode voltage row
Wave travels to the time used in circuit end points as fault point, and ε (t) is jump function.0 mould and 1 mode voltage Sudden Changing Rate are transformed into just
Cathode can obtain
In above formula, Δ vpWith Δ vnRespectively DC line endpoint positive and negative electrode voltage jump amount.
The positive ends of regulation positive and negative electrode DC line endpoint current-limiting inductance voltage are respectively converter station side and DC line
Side, vLpFor the current-limiting inductance voltage of positive DC line endpoint, expression is as follows,
Due to LAFar smaller than LB, therefore, when short trouble occurs for DC line, current-limiting inductance voltage has by a relatively large margin
Mutation, voltage jump amplitude of the mutation amplitude close to DC line endpoint.
3) troubles inside the sample space is analyzed
F2Faulty circuit when short trouble occurs for point is as shown in figure 3, v in figureijpAnd vijn(ij=12,21) it is positive respectively
The voltage on polar curve road and anode circuit endpoint current-limiting inductance.F2When plus earth failure occurs for place, it is equivalent to additional in fault point
One amplitude is UfNegative polarity step voltage source, fault current direction is as shown in solid arrow in Fig. 3.It can by v=Ldi/dt
Know, the increase of fault current necessarily causes v12pAnd v21pPositive polarity mutation.Likewise, when cathode ground fault occurs, phase
When in fault point add an amplitude be UfPositive polarity step voltage source, dotted arrow direction in fault current direction such as Fig. 3
Shown, the increase of fault current causes v12nAnd v21nPositive polarity mutation.By being analyzed above as it can be seen that generating region internal short-circuit failure
When, the mutation polarity of DC line both ends current-limiting inductance voltage is identical, and is all positive polarity.
For symmetrical Bipolar DC power system, in DC line generating region when bipolar short trouble, positive and negative electrode fault current width
Value can all rise rapidly, and therefore, the mutation polarity of positive and negative electrode route both ends current-limiting inductance voltage is grounded event with positive and negative electrode respectively
It is identical when barrier.
4) external area error is analyzed
Still by taking DC line I as an example, as F outside protection zone4When plus earth failure occurs for place, it is equivalent to additional in fault point
One amplitude is UfReverse voltage source, the fault current direction of current through line I is as shown in solid arrow in Fig. 4, due to failure
Backward fault point electric discharge, v12pNegative polarity can occur to be mutated, and v21pPositive polarity mutation can occur.As F outside protection zone4Place occurs negative
When pole ground fault, being equivalent to and adding an amplitude in fault point is UfPositive polarity voltage source, the fault current side of current through line I
To as shown in dotted arrow in Fig. 4, v at this time12nNegative polarity can occur to be mutated, and v21nPositive polarity mutation can occur.By dividing above
As it can be seen that when external short-circuit failure occurs, the voltage jump polarity in the current-limiting inductance of DC line both ends is opposite for analysis.
For symmetrical Bipolar DC power system, when bipolar short trouble outside DC line generating region, positive and negative electrode fault current
Amplitude can all rise rapidly, therefore, the polarity of voltage of positive and negative electrode DC line both ends current-limiting inductance respectively with plus earth, negative
It is identical when pole ground fault.
5) Coupled Interaction Analysis between positive and negative anodes circuit
When monopolar grounding fault occurs for DC line, non-faulting pole tension can dash forward because of the coupling between route
Become.If F in Fig. 11、F2Cathode metal ground fault, the both ends DC line I current-limiting inductance voltage v occur respectively for placeLEmulate wave
Shape difference is as shown in Figure 5, Figure 6.Solid line and chain-dotted line are respectively positive and negative electrode DC line endpoint current-limiting inductance in Fig. 5 and Fig. 6
Voltage waveform.As seen from Figure 5, F1After plus earth failure occurs for place, v12pAnd v12nMutation polarity it is identical, and v21pAnd v21n's
It is opposite to be mutated polarity；As seen from Figure 6, F2When plus earth failure occurs for place, examined in the positive and negative anodes current-limiting inductance of DC line both ends
The first voltage wave polarity measured is all the same.
Anode circuit endpoint current-limiting inductance voltage vLnWith cathode voltage-to-ground variation delta vnMeet expression formula as follows:
In formula, Δ vnExpression formula such as formula (6) shown in.
Define R12And R21Respectively mutual inductor tie point of the both ends DC line I close to converter station 1 and converter station 2.F1Place
When plus earth failure occurs, 0 mould wave and 1 mould wave reach R simultaneously21.Because of Z0>Z1, the Δ v known to formula (4)-(6)nPolarity is
It is negative.By (8) it is found that vLnPolarity be also negative.For R12, since 1 mould velocity of wave is faster than 0 mould velocity of wave, Δ vnPolarity be first
Just, after 0 mould wave reaches, polarity becomes negative.For F2, all it is 1 mould wave prior to 0 mould wave arrival R12Place and R21Place, therefore,
v12nAnd v21nMutation polarity be all first to be positive, 0 mould wave reach after become negative.
By analyzing above as it can be seen that when fault point is close to circuit end points, due to the coupling between route, non-faulting pole
The current-limiting inductance polarity of voltage at both ends is opposite.However, when fault point is far from circuit end points, non-faulting polar curve road both ends current limliting electricity
It is identical to feel polarity of voltage, and is all positive.In the case, no matter line fault whether, route both ends current-limiting inductance voltage pole
Property is all positive.
The building of 2 criterions
According to above-mentioned analysis, it is as follows conclusion can be obtained:
When troubles inside the sample space occurs for DC line, the polarity of voltage of faulty line both ends current-limiting inductance is same to be positive；And generating region
When outer failure, the polarity of voltage of DC line both ends current-limiting inductance is opposite.Accordingly, it can establish based on current-limiting inductance polarity of voltage
Pilot protection criterion.
To reduce coupling influence, to the v in failure post-sampling data windowL(t) it being integrated, expression formula is,
In formula, S is integrated value, tFTo protect Startup time, Δ T is sampling time window.Shown in discrete form such as formula (10),
In formula, Δ t is sampling step length.And it is defined as follows criterion:
In above formula, R, which is limited, flows the polar logical value of inductive drop, Δ2For threshold value, when S is greater than Δ2When, indicate current limliting electricity
The polarity of voltage of sense is positive, and R takes 1；And S is less than or equal to Δ2When, define current-limiting inductance polarity of voltage be it is non-just, R takes 0.Definition
Route both ends are respectively the end M and N-terminal, and after protection starting, the logical value for judging local terminal polarity of voltage respectively is protected at route both ends, into
And determine whether break down in this section by comparing the logical value at both ends, Protection criteria is as follows:
In formula, RMAnd RNThe respectively R value at the end DC line M and N-terminal.
If it is determined that troubles inside the sample space, and judge after being out of order extremely, it just sends and jumps to the dc circuit breaker at failure pole both ends
Lock signal, faulty line is cut off, and realizes the protection to DC grid.
Utilize the emulation mould built in PSCAD/EMTDC according to the topology of four end flexible direct current power grid of Zhangbei County and parameter
Type carries out simulation analysis.
1) model is established
For the validity for verifying proposed guard method, the topological structure and parameter of reference four end flexible direct current power grid of Zhangbei County,
Simulation model is constructed using simulation software PSCAD/EMTDC.DC line is used according to frequency model.Fault point F1~F6Position
As shown in Figure 1, wherein F1、F4Positioned at route I and route II endpoint, F2、F5Positioned at route I and the midpoint route III, F3Positioned at the change of current
It stands on 1 DC bus, F6Positioned at exchange side.The failure generation moment is set as 3.0s, sample frequency 50kHz, sampling time
Window Δ T is selected as 0.5ms.In view of the sensitivity and reliability of criterion, by threshold value Δ1It is set as 20kV, Δ2It is set as 25V
s.Without loss of generality, it selects route I for research object, F is respectively set1–F6Totally 6 fault points.The key parameter of simulation model is such as
Shown in table 1.
1 simulation model key parameter of table
2) typical fault emulates
A, troubles inside the sample space emulates
If fault point F1、F2Metallicity plus earth failure occurs respectively for place, and the simulation waveform of current-limiting inductance voltage is respectively such as
Shown in Fig. 5 and Fig. 6, the results are shown in Table 2 for emulation data and differentiation.Fault point F2The ground connection event of metallicity cathode occurs respectively for place
When barrier, bipolar short trouble, simulation waveform difference is as shown in Figure 7, Figure 8, and simulation result is as shown in table 2.As can be seen from Table 2, failure
The R value at polar curve road both ends is 1, and R value takes 0 to the S value of non-faulting pole due to being less than threshold value.Therefore, mentioned criterion can be correct
Identify internal fault external fault and its fault type.
Simulation result when 2 troubles inside the sample space of table
B, external area error emulates
When external area error occurs, the effective of mentioned guard method is verified by taking bipolar short trouble the most serious as an example
Property.For F3The bus-bar fault at place, vLSimulation waveform as shown in figure 9, simulation result and differentiate result listed in table 3.It is right
In F4And F5The failure at place, vLSimulation waveform it is as shown in Figure 10 and Figure 11.Emulation data and differentiation result are also listed in table 3.
Data are emulated as shown in Table 3 and differentiate result it is found that the guard method can correctly determine internal fault external fault.
Simulation result when 3 external area error of table
For exchanging side fault point F6Even if three phase short circuit fault the most serious occurs, which is also difficult to open
It is dynamic.Therefore, when exchange side failure occurs, which will not be judged by accident.
C, the influence of transition resistance
In order to investigate influence of the fault point transition resistance to this protection, in F1、F2Plus earth failure is respectively set in place, therefore
Barrier resistance takes 200 Ω, 400 Ω, and simulation result is as shown in table 4.By the emulation data of table 4 it is found that fault resstance is bigger, ▽ vL, S
It is worth smaller.But even if transition resistance increases to 400 Ω, Protection criteria still can accurately determine troubles inside the sample space.By with
Upper emulation data are it is found that protection threshold value Δ1It is set as 20 (kV), Δ2When being set as 25 (Vs), Protection criteria has enough
Sensitivity and reliability.
Simulation result when 4 fault resstance of table is larger
3) analysis the time required to protection
Enable TPThe time required to occurring to differentiation to be out of order for failure, TPIt can be indicated with following formula,
TP=Δ T+T1+T2 (13)
In formula, Δ T is sampling time, T1For signal transmission time, T2For the delay considered.Signal transmission time T1Packet
Fault traveling wave is included from fault point F1Travel to R12Time T used1 a, fiber optic communication signal is from R12It is transferred to R21Time T used1 b；Institute
Consider delay T2Including failure detection time, signal processing time and certain allowance, herein based on 0.5ms.1 mould velocity of wave is in frame
It is about 294km/ms in ceases to be busy, the spread speed of signal in a fiber is most 200km/ms fastly.In Figure 12, failure betides F1Place
When, T1 aMaximum value can be obtained, at this point, T the time required to the protection of route IPMaximum value can be obtained.By above to route I's
Analysis, can obtain the maximum value the time required to each route protection, as shown in table 5.By table 5 as it can be seen that the pilot protection is applied to Zhangbei County
When DC engineering, the fault distinguishing time of longest route is not more than 3ms.Therefore, the quick-action of mentioned pilot protection is very
By force.
Table 5 protects required maximum duration
| DC line | T1(ms) | T2(ms) | ΔT(ms) | TP(ms) |
| Route I | 1.73 | 0.50 | 0.50 | 2.73 |
| Route II | 0.42 | 0.50 | 0.50 | 1.42 |
| Route III | 1.58 | 0.50 | 0.50 | 2.58 |
| Route IV | 1.75 | 0.50 | 0.50 | 2.75 |
The present invention is first to current-limiting inductance voltage vLFaulty generation is detected whether by voltage gradient algorithm, if detected
Failure then judges current-limiting inductance polarity of voltage, and whether all to judge route both ends current-limiting inductance polarity of voltage by fiber optic communication
It is positive.If route both ends current-limiting inductance polarity of voltage is all positive, illustrate that troubles inside the sample space occurs.The principle and algorithm of the invention
Simply, the mathematical tools such as Fast Fourier Transform (FFT), wavelet transformation are not needed and carry out frequency dividing or traveling wave capture, without route two sides
Data are synchronous, it is easy to accomplish；Data window needed for Protection criteria is short, and does not need additional failure pole discriminating step, quick-action
By force；When troubles inside the sample space, the voltage jump amplitude of current-limiting inductance is larger, even if fault point transition resistance is larger, still is able to reliable
Identify internal fault external fault.Therefore, protection scheme sensitivity with higher, reliability and absolute selectivity.
Embodiment two
In some embodiments, a kind of vertical connection of the multiterminal flexible direct current power grid based on current-limiting inductance polarity of voltage is disclosed
Protection system, including server, the server include memory, processor and storage on a memory and can be on a processor
The computer program of operation, the processor are realized described in embodiment one when executing described program based on current-limiting inductance voltage
Polar multiterminal flexible direct current power grid longitudinal protection method.
Embodiment three
In some embodiments, a kind of computer readable storage medium is disclosed, computer program is stored thereon with, it should
The multiterminal flexible direct current power grid based on current-limiting inductance polarity of voltage described in embodiment one is executed when program is executed by processor
Longitudinal protection method.
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 (5)
1. the multiterminal flexible direct current power grid longitudinal protection method based on current-limiting inductance polarity of voltage characterized by comprising
(1) voltage in the current-limiting inductance of DC line both ends is acquired in real time；
(2) by voltage gradient algorithm, the whether faulty generation of collected voltage detecting DC line is utilized；
(3) if detecting failure, the voltage value in sampled data window is integrated, by comparing integrated value and setting door
The size relation of threshold value, and then judge current-limiting inductance polarity of voltage；
(4) polarity of voltage of transmission line of electricity both ends current-limiting inductance is compared, if polarity is all positive, is judged as event in area
Barrier, is otherwise judged as external area error.
2. the multiterminal flexible direct current power grid longitudinal protection method based on current-limiting inductance polarity of voltage as described in claim 1,
It is characterized in that, by voltage gradient algorithm, using the whether faulty generation of collected current-limiting inductance voltage detecting, specifically:
Wherein, vL(k)、The voltage value and voltage gradient value of k-th of sampled point respectively in current-limiting inductance；Δ1For starting
Threshold value；K and j is sampled point.
3. the multiterminal flexible direct current power grid longitudinal protection method based on current-limiting inductance polarity of voltage as described in claim 1,
It is characterized in that, to the v in sampled data windowLIt is integrated, by comparing the size relation of integrated value and setting threshold value, in turn
Judge current-limiting inductance polarity of voltage, specifically:
To the voltage v in the current-limiting inductance of DC line both endsLIt is integrated respectively, if in the current-limiting inductance of DC line one end
Voltage integrating meter value be greater than setting threshold value, then it is assumed that the polarity of voltage in the end current-limiting inductance is positive；Otherwise, the end current limliting electricity
Voltage jump polarity in sense be it is non-just.
4. the multiterminal flexible direct current power grid pilot protection system based on current-limiting inductance polarity of voltage, which is characterized in that including service
Device, the server include memory, processor and storage on a memory and the computer program that can run on a processor,
The processor realizes the described in any item multiterminal based on current-limiting inductance polarity of voltage of claim 1-3 when executing described program
Flexible direct current power grid longitudinal protection method.
5. a kind of computer readable storage medium, is stored thereon with computer program, which is characterized in that the program is held by processor
Perform claim requires the described in any item multiterminal flexible direct current power grid pilot protections based on current-limiting inductance polarity of voltage of 1-3 when row
Method.
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| CN110308370A (en) * | 2019-07-24 | 2019-10-08 | 合肥工业大学 | Flexible direct current power grid direct-current short circuit fault rapid detecting method based on MMC |
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Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101615785A (en) * | 2009-07-31 | 2009-12-30 | 西安交通大学 | Electric transmission line longitudinal protection method based on shunt reactor |
| CN105548819A (en) * | 2016-02-19 | 2016-05-04 | 国网四川省电力公司电力科学研究院 | High-voltage direct current transmission line internal fault and external fault identification method based on backward traveling waves |
| CN106058828A (en) * | 2016-07-18 | 2016-10-26 | 天津大学 | Multi-terminal flexible DC power grid line direction pilot protection method |
| CN107979075A (en) * | 2017-11-27 | 2018-05-01 | 山东大学 | A kind of multiterminal flexible direct current power grid DC line Non-unit protection method |
| CN108226708A (en) * | 2017-12-15 | 2018-06-29 | 华南理工大学 | A kind of fast failure method of discrimination of the power grid of multiterminal element containing MMC |
-
2018
- 2018-09-20 CN CN201811098052.1A patent/CN109217267B/en active Active
Patent Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101615785A (en) * | 2009-07-31 | 2009-12-30 | 西安交通大学 | Electric transmission line longitudinal protection method based on shunt reactor |
| CN105548819A (en) * | 2016-02-19 | 2016-05-04 | 国网四川省电力公司电力科学研究院 | High-voltage direct current transmission line internal fault and external fault identification method based on backward traveling waves |
| CN106058828A (en) * | 2016-07-18 | 2016-10-26 | 天津大学 | Multi-terminal flexible DC power grid line direction pilot protection method |
| CN107979075A (en) * | 2017-11-27 | 2018-05-01 | 山东大学 | A kind of multiterminal flexible direct current power grid DC line Non-unit protection method |
| CN108226708A (en) * | 2017-12-15 | 2018-06-29 | 华南理工大学 | A kind of fast failure method of discrimination of the power grid of multiterminal element containing MMC |
Cited By (13)
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|---|---|---|---|---|
| CN110308370A (en) * | 2019-07-24 | 2019-10-08 | 合肥工业大学 | Flexible direct current power grid direct-current short circuit fault rapid detecting method based on MMC |
| CN110687399A (en) * | 2019-10-15 | 2020-01-14 | 贵州电网有限责任公司 | Method for judging waveform fault starting time of power distribution network fault indicator |
| CN111579849B (en) * | 2020-04-10 | 2022-09-16 | 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 | Harmonic current distribution obtaining method and device |
| CN111579849A (en) * | 2020-04-10 | 2020-08-25 | 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 | Harmonic current distribution obtaining method and device |
| CN111856322A (en) * | 2020-05-09 | 2020-10-30 | 上海交通大学 | Direct-current distribution network bipolar short-circuit fault accurate positioning method and device based on MMC |
| CN111614067A (en) * | 2020-06-08 | 2020-09-01 | 广州市扬新技术研究有限责任公司 | Direct current traction pilot protection system and method based on optical fiber communication |
| CN111830313A (en) * | 2020-07-07 | 2020-10-27 | 国网福建省电力有限公司电力科学研究院 | Transient overvoltage broadband monitoring system for modular multilevel converter |
| CN113376549A (en) * | 2021-05-26 | 2021-09-10 | 国网上海能源互联网研究院有限公司 | Pilot protection method and system for flexible direct current power distribution network |
| CN113376549B (en) * | 2021-05-26 | 2024-04-19 | 国网上海能源互联网研究院有限公司 | Pilot protection method and pilot protection system for flexible direct-current power distribution network |
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