CN107706909A - Oscillation center identifying system and its method based on frequecy characteristic under multi-frequency oscillation - Google Patents
Oscillation center identifying system and its method based on frequecy characteristic under multi-frequency oscillation Download PDFInfo
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- CN107706909A CN107706909A CN201710840778.7A CN201710840778A CN107706909A CN 107706909 A CN107706909 A CN 107706909A CN 201710840778 A CN201710840778 A CN 201710840778A CN 107706909 A CN107706909 A CN 107706909A
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- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02J—CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
- H02J3/00—Circuit arrangements for ac mains or ac distribution networks
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- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02J—CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
- H02J2203/00—Indexing scheme relating to details of circuit arrangements for AC mains or AC distribution networks
- H02J2203/20—Simulating, e g planning, reliability check, modelling or computer assisted design [CAD]
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Abstract
The invention belongs to Power System Stability Analysis technical field, more particularly to oscillation center identifying system and its method based on frequecy characteristic under a kind of multi-frequency oscillation, including data acquisition module, step-out/oscillation center pass through discrimination module, step-out/oscillation center location identification module and result output module；The data acquisition module is used to gathering network architecture parameters, each side bus frequency in system；Step-out/oscillation center passes through discrimination module and differentiates whether step-out/oscillation center passes through, and then discriminates whether in T link protection domains；The step-out/oscillation center location identification module passes through discrimination module in step-out/oscillation center and differentiates that nothing passes through phenomenon, when i.e. step-out/oscillation center is located at certain side in three end systems, according to the side bus frequency situation of change feature opposite with remaining two side bus frequency situation of change, step-out/oscillation center position is identified, and analysis result is sent to result output module.
Description
Technical field
The invention belongs to frequecy characteristic is based under Power System Stability Analysis technical field, more particularly to a kind of multi-frequency oscillation
Oscillation center identifying system and its method.
Background technology
When Operation of Electric Systems is by violent disturbance, generator can not keep relative stability in system, step-out will occur
Vibration, to prevent from causing the collapse of power system, on the one hand need system sectionalizing is some subsystems in step-out section to protect
Hold stable operation；On the other hand, it is necessary to prevent the protective relaying device in power network because of vibration and malfunction so as to expanding disturbing influence
Scope.Step-out/oscillation center be accurately positioned and follow the trail of be power system oscillation research importance, can be power system lose
One of walk disconnection device and important reference is provided, while be also the important basis for estimation of protection out-of-step blocking.As power network is transported
Professional etiquette mould expands day by day, and is contacted between regional power grid further closely, when being broken down in power system and then triggering vibration, loses
Step/oscillation center is also no longer secured to certain point on circuit, and may be moved between each regional power grid.In multi-frequency oscillation scene
Under, electrical quantity changing rule etc. has large change, traditional localization method based on two machine system models, for multi-frequency oscillation field
The situation of step-out/oscillation center movement may be no longer applicable under scape.
The research on oscillation center identification method for tracing is mostly based on two machine system models at present, and is broadly divided into two
Class, one kind are to realize the positioning of step-out/oscillation center using local information, such as based on apparent impedance track, IMPEDANCE ANGLE SEPARATION orMethod etc., can be accurately positioned oscillation center.It is another kind of be using Wide-area Measurement Information realize positioning, at present, based on
On the basis of the recognition methods of two machine system model oscillation center electrical quantity frequecy characteristics, some scholars have carried out multi-frequency oscillation field
The research of step-out/oscillation center localization method under scape, analyzes the frequency distribution feature under multi-frequency oscillation scene, and propose mistake
The localization method at step center, however assuming that condition is that all system impedances, line impedance are equal, with actual conditions difference compared with
Greatly.
The content of the invention
In consideration of it, the present invention proposes oscillation center identifying system and its side under a kind of multi-frequency oscillation based on frequecy characteristic
Method.
System includes：
Data acquisition module, step-out/oscillation center pass through discrimination module, step-out/oscillation center location identification module and knot
Fruit output module；The data acquisition module is used to gathering network architecture parameters, each side bus frequency in system；Step-out/vibration
Center passes through discrimination module and differentiates whether step-out/oscillation center passes through, and then discriminates whether in T link protection domains
It is interior；The step-out/oscillation center location identification module is passed through discrimination module in step-out/oscillation center and differentiated without phenomenon is passed through, i.e.,
When step-out/oscillation center is located at certain side in three end systems, according to the side bus frequency situation of change and remaining two side bus frequency
The opposite feature of rate situation of change, step-out/oscillation center position is identified, and analysis result is sent to result output module.
Method comprises the following steps：
Step 1：One point O is connected in build three machine equivalence system models by three-line with three side power supplys；
Step 2：Any both sides equivalent electric is obtained according to the phase relation of each side equivalent source potential oscillations initial time
The phase angle difference of gesture；
Step 3：O point current equations are listed according to Kirchhoff's current law (KCL) and are derived from each side current instantaneous value expression
Formula, and obtain power frequency feature under multi-machine oscillation scene with reference to trigonometric function relation；
Step 4：Any point p power frequency feature is analyzed, obtains electric voltage frequency feature under multi-machine oscillation scene, analysis
Draw electric voltage frequency distribution and potential phase angle, relative angular speed, the relation of particular location；
Step 5：The offset boundary of oscillation center is obtained according to electric voltage frequency consecutive variations process, skew solstics is step-out
Center；
Step 6：If it is violent compared with the change of other bus frequencies at a certain bus, or the frequency change Duan Bo that bus two is adjacent
Shape is reverse, then illustrates that out-of-step center passes through, then need not carry out oscillation center identification, on the contrary then be identified by step 7；
Step 7：Detect each side bus frequency, it is consistent if the change of certain both sides frequency and with the change of opposite side frequency on the contrary, if
Oscillation center appears in opposite side, and the oscillation center point of system under multi-machine oscillation scene is determined according to frequency change severe degree
Position.
The beneficial effects of the invention are as follows：The present invention carries the voltage x current based on any point in system and expresses formula, derives
The function expression of its voltage x current frequency, analyze under multi-machine oscillation scene, the situation of change of voltage x current frequency in system
And distribution situation, and have studied system frequency distribution and the relation of step-out/oscillation center, it is proposed that one kind is based on system busbar frequency
The oscillation center identification tracing scheme of rate situation of change.Simulation result based on DIgSILENT/PowerFactory shows, this
The itd is proposed scheme of invention can effectively follow the trail of multi-frequency oscillation system oscillation center, can be that Out-of-Step Splitting Systems and protection vibration are closed
Lock lays the foundation.
Brief description of the drawings
Fig. 1 is the oscillation center identifying system structure based on frequecy characteristic under a kind of multi-frequency oscillation scene provided by the invention
Figure.
Fig. 2 is the T welding system protection device configuration diagrams in embodiment of the present invention.
Fig. 3 is each side equivalent source potential phase relation of vibration initial time in embodiment of the present invention.
Fig. 4 is δ in the vibration in embodiment of the present invention12Level off to 0 when each side equivalent source potential phase relation.
Fig. 5 is δ in the vibration in embodiment of the present invention13Level off to 0 when each side equivalent source potential phase relation.
Fig. 6 is each dot frequency variation diagram in A sides in embodiment of the present invention.
Fig. 7 is ρ in the oscillatory process in embodiment of the present inventionAPoint voltage oscillogram.
Fig. 8 is each dot frequency variation diagram in B sides in embodiment of the present invention.
Fig. 9 is each dot frequency variation diagram in C sides in embodiment of the present invention.
Figure 10 be at bus in embodiment of the present invention frequency with the distribution map of generator rotor angle.
Figure 11 is system in embodiment of the present invention with respect to generator rotor angle simulation curve.
Figure 12 is the side electric current of subsystem 1 in embodiment of the present invention.
Figure 13 is the side electric current of subsystem 2 in embodiment of the present invention.
Figure 14 is the side electric current of subsystem 3 in embodiment of the present invention.
Figure 15 is frequency fluctuation situation at each side system bus in embodiment of the present invention.
Figure 16 is the monitoring point voltage change curve in embodiment of the present invention.
Embodiment
Below in conjunction with the accompanying drawings, embodiment is elaborated.
Fig. 1 is the oscillation center identifying system structure based on frequecy characteristic under a kind of multi-frequency oscillation scene provided by the invention
Figure, including sequentially connected data acquisition module, step-out/oscillation center pass through discrimination module, step-out/oscillation center position identification
Module and result output module.
Fig. 2 is the equivalent three machines system model of multi-frequency oscillation,Respectively bus 1, bus 2 and the dorsal part of bus 3
Equivalent electromotive force, Z1、Z2、Z3Equivalent system impedance, Z respectively corresponding to dorsal part1O、Z2OAnd Z3ORespectively bus 1, the and of bus 2
Bus 3 arrives the equivalent impedance of O points.R1, R2, R3 represent each side and are installed on bus bar side or the protection device of outlet respectively.Analysis
During, it is specified that electric current flows to circuit as just by bus, if system the superior and the subordinate element impedance angle is equal.
Fig. 3 be each side equivalent source potential oscillations initial time phase relation, ω be A sides power supply angular frequency, Δ ω12
For B sides equivalent potentialRelative to the angular frequency of A sides electrical source voltage, Δ ω13For C sides equivalent potentialRelative to A sides power supply electricity
The angular frequency of gesture.In oscillatory process, if using A sides electrical source voltage as reference, any time, B sides equivalent potentialC sides are equivalent
PotentialRelative to A sides equivalent potentialPhase angle difference be respectively：
In formula, δ02And δ03Respectively vibrate initial timeRelative toPhase angle.A side systems represent generator
The system of circuit where G1 and G1 compositions, B side systems are the system of circuit where generator G2 and G2 compositions, and C side systems are hair
The system of circuit where motor G3 and G3 compositions.
Power frequency feature under multi-frequency oscillation scene：
It is as follows that O point current equations are listed according to Kirchhoff's current law (KCL)：
In formula：For O point voltages, ZAΣ=Z1+Z1OFor A side system comprehensive impedances, ZBΣ=Z2+Z2OIntegrated for B side systems
Impedance, ZCΣ=Z3+Z3OFor C side system comprehensive impedances.
The voltage phasor expression formula that O points can be obtained according to formula (2) is：
According to O point voltages and each side system equivalence potential expression formula, each side system electric current phasor can be derived.Using A sides as
Example, the current expression of A sides are：
Each side electrical source voltage is set during analysis as E, the instantaneous value that A sides electric current can be write out according to formula (1) and (4) is expressed
Formula is：
According to trigonometric function relation, formula (5) can be rewritten as：
From formula (6), the frequecy characteristic of electric current and two machines vibrate the frequency spy of electric current under scene under multi-machine oscillation scene
Sign is different, and power frequency is no longer the average value of both sides supply frequency, but is by an amplitudeFrequency isIt is with an amplitudeFrequency isTwo current components be formed by stacking.
Convolution (5) and formula (6), are analyzed power frequency and are discussed below：
1) δ is worked as12Level off to 0 when, formula (6) Part I amplitudeAlso zero is leveled off to, the dominant frequency of electric current
ForNow, the phase relation of each side potential of system is as shown in figure 4, can regard A sides as with B sides power supply relative to C sides power supply
Vibration.
2) δ is worked as13Level off to 0 when, formula (6) Part II amplitudeLevel off to zero, now the dominant pilot of electric current
Rate isNow, the phase relation of each side potential of system is as shown in figure 5, can regard A sides as with C sides power supply relative to B sides electricity
The vibration in source.
3) δ is worked as2=δ3When, i.e., when B side systems are synchronous with C side systems, system degradation is two machine system oscillation models, this
When power frequency be
Electric voltage frequency feature under multi-frequency oscillation scene：
If p points are any point in A side systems, the equivalent electrical distance of the point to A side systems is p × LAO, and p is [0,1]
Any real number in section, then the voltage expression of p points be：
A sides current expression (4) is substituted into formula (7), and is transformed to amplitude and the form of phase angle：
In formula：SmAnd SnRespectivelyReal and imaginary parts, expression formula is：
ForEquivalent phase angle.
The angular frequency of p point voltages is represented by the derived function of its phase angle, is：
In formula：Δ ω is the increment of angular frequency.
It is not only relevant with potential phase angle, relative angular speed to can be seen that electric voltage frequency distribution from above-mentioned derivation, at the same also with
Location is relevant in systems for the point.Further look at it can be found that angular frequency increment Delta ω and the voltage magnitude
Square it is in inverse ratio.Therefore, frequency distribution is influenceed very big by system voltage distribution.
The increment of a certain dot frequency and the voltage magnitude square is in inverse ratio in system.And at out-of-step center, voltage
Amplitude is zero, therefore the increment of frequency levels off to infinity at out-of-step center, and frequency will appear from distorting at out-of-step center.It is right
Other points in system, closer to out-of-step center, then the voltage magnitude is smaller, or even close to zero, thus frequency increment is got over
Greatly, frequency change is also more violent.
The change of system generator rotor angle is a continuous process, therefore, is similarly connected according to the frequency change that formula (9) calculates
It is continuous.Oscillation center is constantly moved in systems, and O points are returned after being moved to solstics to a certain side from O points, and further to it
He moves system side.Oscillation center has clear and definite offset boundary, and boundary function value is only related to structural parameters.In oscillatory process
In, A sides oscillation center is moved to solstics ρAAfter return, the point is also the out-of-step center point of system under certain oscillation mode.
Z in formula (2) might as well be setAΣ:ZBΣ:ZCΣ=10:5:4, system impedance angle is 86.5 °, thus can calculate the vibration of A sides
The skew solstics ρ at centerAPosition is p=0.6364.Make Δ ω12With Δ ω13Zero is all higher than, A side-lines can be obtained according to formula (9)
Each point electric voltage frequency in system, A side system partial dots are selected to make its frequency variation diagram as shown in fig. 6, the electricity of these points can be made simultaneously
Corrugating is as shown in Figure 7.As seen from Figure 7 as t=40s, ρAPoint voltage zero-cross, it is the out-of-step center of system.
It can be seen that with reference to Fig. 6 and Fig. 7 opposite in out-of-step center point both sides, system frequency situation of change.Out-of-step center goes out
At the time of on the line now, each point frequency variation reaches maximum in system.Meanwhile the frequency at p=0.8 and at p=0.5
Excursion is significantly less than the frequency range at p=0.7 and at p=0.6, therefore, closer to the change of out-of-step center frequency
It is more violent.
Fig. 8 and Fig. 9 is respectively B sides, the frequency situation of change of C side system partial dots.B sides oscillation center can similarly be calculated
Skew solstics ρBPosition is p=0.7778, the skew solstics ρ of C sides oscillation centerCPosition is p=0.8750, is vibrated
Cheng Zhong, ρBAnd ρC2 points may be system out-of-step center.In order to observe step-out/oscillation center both sides frequency situation of change, make
The frequency of each point is as shown in Figure 8 and Figure 9 at B sides and C sides p=0.7 to p=1.As can be seen that during t=0s~22.8s, B
Each dot frequency situation of change is consistent in side system, and out-of-step center is not located at the side, but in C side systems at p=0.9 and at p=1.0
Frequency is substantially reverse, and frequency fluctuation is very big, and therefore, out-of-step center is between C sides p=0.9 and p=1.0.
It is can also be seen that with reference to Fig. 6, Fig. 8 and Fig. 9 when step-out/oscillation center is by certain point, by frequency before and after the point
The situation of change contrast of rate waveform, such as p=0.8, p=0.7 point in A side systems, in step-out/oscillation center without this
During a little point, frequency situation of change is identical with other points, in step-out/oscillation center after this is 2 points, frequency situation of change with separately
Outer 2 points on the contrary, and frequency situation changes after step-out/oscillation center is from A side systems to the movement of system other sides, with
Other 2 points identical；Before step-out/oscillation center is by certain point, the point is in the side of step-out/oscillation center all the time, because
The situation of change of this frequency waveform is consistent, and such as p=0.5, p=0.6 point in A side systems, step-out/oscillation center is all the time not
By these points, 2 points of the frequency situation of change keeps constant, and the characteristic is referred to as that step-out/oscillation center passes through characteristic, utilizes
What the characteristic can differentiate step-out/oscillation center passes through situation.
Step-out/oscillation center position is identified based on bus frequecy characteristic：
If Δ ω12With Δ ω13Zero is all higher than, δ can be made12And δ13Under different generator rotor angle value conditions, difference in system
Electric voltage frequency change curve it is as shown in Figure 10, successively represent work as δ12And δ13When changing in [- π, π] section, A sides, B sides and C
Frequency situation of change at side bus.It can be found that when step-out/oscillation center appears in A side systems, B side systems and C side-lines
Frequency situation of change of uniting is consistent but opposite with A sides frequency situation of change；When step-out/oscillation center appears in B side systems, A sides
System is consistent with C side system frequency situations of change, but opposite with B sides frequency situation of change；When step-out/oscillation center appears in C
During side system, A side systems are consistent with B side system frequency situations of change, but opposite with C sides frequency situation of change.
Understood according to formula (9), the frequency of frequency and the side power supply of certain point voltage and the side electric current in certain side system
Frequency is relevant.By the analysis shows of power frequency feature under multi-frequency oscillation scene, the frequency of system power and each side system power supply
Frequency and three equivalent potentials relative position about (with reference to figure 4 and Fig. 5).Meanwhile when other both sides power supply generator rotor angles
When more close, the degree that step-out/oscillation center is offset to the side system is bigger, and under the scene, three machine systems can be approximately two
Machine system.Multi-computer system is connect for T, because relative generator rotor angle constantly changes, it is periodically short to be considered as a group of planes in cycle of oscillation
When recombinate, so as to form two machine oscillation modes of different Unit Combinations.If there is out-of-step center in certain side, two systems in combination
Electric voltage frequency situation of change is consistent, and opposite with out-of-step center opposite side (unit side) electric voltage frequency situation of change.Therefore, monitor
The frequency situation of change of each side bus, you can judge section situation residing for out-of-step center.
For multi-frequency oscillation scene, the present invention proposes a kind of step-out/oscillation center based on the change of system busbar frequency
Identifying system and its method.The system and method have the characteristics that：
1) conclusion of system power frequency-invariant is no longer applicable in the case where T connects multi-frequency oscillation scene in two machine system oscillations.T connects
System power is formed by stacking by two different components of frequency, and in generator rotor angle rocking process, different dominant frequencies may be presented.
2) frequency of each point is together decided on by system generator rotor angle, relative angular speed and present position in multi-frequency oscillation system,
And the increment of frequency and the voltage magnitude square are inversely proportional.
3) when step-out/oscillation center occurs, each point frequency variation reaches extreme value, at step-out/oscillation center, frequency hair
Raw distortion.The point nearer apart from step-out/oscillation center, the change of its frequency is more violent, and step-out/each dot frequency in oscillation center both sides
Situation of change is opposite.
4) when step-out/oscillation center falls into certain side in three end systems, the side bus frequency situation of change with remaining two
Side bus frequency situation of change is on the contrary, based on this composition system step-out/oscillation center identifying schemes, simulation result shows the program
Step-out/oscillation center position can effectively be identified.
Embodiment
Simulation Model based on DIgSILENT/PowerFactory platform buildings is as shown in Fig. 2 wherein system is each
Circuit model is identical, and the positive order parameter of circuit is：X1=0.4497 Ω/km R1=0.0529 Ω/km, c1=0.0064 μ F/km,
Zero sequence parameter is：X0=0.6027 Ω/km R0=0.08145 Ω/km, c0=0.004 μ F/km, circuit L1 length is 80km,
Circuit L2 length is 200km, and circuit L3 length is 120km, G1 system positive sequence equivalent impedance parameter 1.693+j37.528 Ω, zero
Sequence impedance Z 0=0.410+j37.18.42 Ω；G2 system positive sequence equivalent impedance parameters are：Z1=1.21+j57 Ω, zero sequence impedance
Z0=0.6+j9.091 Ω, G3 system positive sequence equivalent impedance parameters are：Z1=0.77+j43.235 Ω, zero sequence impedance Z0=0.6+
j29.097Ω.For convenience of narration, each side system is numbered with generator and named, i.e.,：Subsystem 1 represents side line where generator G1
The system of side line road and its composition where road and the system of G1 compositions, subsystem 2 and subsystem 3 represent G2 and G3 respectively.Emulation
Time amounts to 6s, analogue system frequency on the basis of power frequency (50Hz).
Using G3 as with reference to machine in simulation process, under original state, system stable operation, G1 is 20 ° relative to G3 generator rotor angle,
G1 is 10 ° relative to G3 generator rotor angle.System starts to vibrate during t=0.5s, and system is with respect to generator rotor angle change curve such as Figure 11 in emulation
It is shown.As seen from the figure, after 0.5s, G1 generator rotor angle and G2 generator rotor angle are gradually arranged relative to G3, show the state of three machines vibration.
Current waveform profile is measured in oscillatory process in subsystem 1, subsystem 2 and subsystem 3 respectively as shown in Figure 12, Figure 13, Figure 14.
It can be seen that in the system oscillation later stage, cycle of oscillation shortens, and step-out speed is accelerated.
In simulation process, frequency monitoring device is provided with bus Bus1, Bus2 and Bus3 respectively.The frequency of each side bus becomes
Change situation is as shown in figure 15, can be divided into 12 by the situation that frequency changes in simulation process is vibrated according to the conclusion of previous analysis
Stage, each stage characterize the process that step-out/oscillation center moves in different sub-systems.Because moving process is similar,
Here in 10 stages before only analyzing, a period is represented between every two black dotted lines, in fig.15 with numeral mark.1st
In the stage, measurement frequency situation of change is consistent with measurement frequency situation of change at Bus2 at t=0.5s~1.517s, Bus1,
With measurement frequency situation of change at Bus3 on the contrary, step-out/oscillation center is located on L3.The stage is divided into two parts, in t=0.5s
During~1.036s, step-out/oscillation center reaches the maximum in this stage to the internal blas of subsystem 3, each side frequency shift (FS)；This
Afterwards, during t=1.036s~1.517s, step-out/oscillation center starts from being moved to O inside subsystem 3.2nd stage, system
Step-out/oscillation center is still then back to the skew of subsystem 3.3rd stage, at the bus of subsystem 1 frequency situation of change switch to
Frequency situation of change is consistent at Bus3, and with frequency situation of change at Bus2 on the contrary, step-out/oscillation center is located on L2, in t=
During 2.293s~2.517s, step-out/oscillation center is offset to G2 sides, and as t=2.517s, frequency, which changes, reaches the period
Maximum, during t=2.517s~2.817s, step-out/oscillation center starts by the lateral O points skew of the nearly buses of L2.Similarly may be used
With analysis, the 4th stage, step-out/oscillation center is offset to L3 sides, and in the 5th stage, step-out/oscillation center is offset to L2 sides, this
Afterwards, step-out/oscillation center constantly reciprocates on L2 and L3.
Due to can not accurately obtain the accurate location of step-out/oscillation center according to measurement, in order to verify said process
Correctness, the offset boundary of each side step-out/oscillation center is selected as monitoring point, the situation of change of monitoring system voltage.Pass through
Calculate, select the point nod2 of distance O points 118.88km on distance O points 36.32km point nod1, circuit L2 on circuit L1 respectively,
Distance O points 24.52km point nod3 is as monitoring point on circuit L3.Due to the skew that these three voltage monitoring points are oscillation center
Boundary point, therefore, the voltage change situation of the point can effectively reflect the mobile route of oscillation center.In simulation process, three
The voltage change situation of voltage monitoring point is as shown in figure 16.
Divided according to Figure 15 time, the simulation process shown in Figure 16 is divided into 12 stages, and made accordingly in figure
Mark.It can be seen that each stage can be completely corresponding with Figure 16 in Figure 15, and monitoring point voltage change situation is analyzed with Figure 15
Conclusion is completely the same.Such as, in the 1st stage, during t=0.5s~1.517s, step-out/oscillation center is located at the side of subsystem 3, should
Stage is divided into two parts, and during t=0.5s~1.036s, each monitoring point voltage declines, wherein the side monitoring point of subsystem 3
Nod3 voltages are minimum, and hereafter, during t=1.036s~1.517s, each monitoring point voltage rises, and nod3 points voltage is still for most
Low, step-out/oscillation center returns inside subsystem 3 to O.2nd stage, each monitoring point voltage change situation and the 1st stage phase
Seemingly, system step-out/oscillation center is still then back to the skew of subsystem 3；3rd stage, step-out/oscillation center are located at subsystem
2 sides, voltage declines rapidly and fallen in 2.517s as 0 at the nod2 of monitoring point；Other stages can do similar analysis.Embodiment emulates
As a result show, the oscillation center recognition methods based on frequecy characteristic, passes through monitoring under multi-frequency oscillation scene proposed by the invention
System busbar frequency situation of change, can effective identification system step-out/oscillation center position.
Above-described embodiment is only the preferable embodiment of the present invention, but protection scope of the present invention is not limited to
This, any one skilled in the art the invention discloses technical scope in, the change that can readily occur in or replace
Change, should all be included within the scope of the present invention.Therefore, protection scope of the present invention should be with the protection model of claim
Enclose and be defined.
Claims (2)
- A kind of 1. oscillation center identifying system based on frequecy characteristic under multi-frequency oscillation, it is characterised in that including：Data acquisition module, step-out/oscillation center pass through discrimination module, step-out/oscillation center location identification module and result is defeated Go out module；The data acquisition module is used to gathering network architecture parameters, each side bus frequency in system；Step-out/oscillation center Pass through discrimination module and differentiate whether step-out/oscillation center passes through, and then discriminate whether in T link protection domains；Institute State step-out/oscillation center location identification module and pass through discrimination module in step-out/oscillation center and differentiate without phenomenon is passed through, i.e., step-out/ When oscillation center is located at certain side in three end systems, changed according to the side bus frequency situation of change and remaining two side bus frequency The opposite feature of situation, step-out/oscillation center position is identified, and analysis result is sent to result output module.
- 2. the oscillation center recognition methods based on frequecy characteristic under a kind of multi-frequency oscillation, it is characterised in that comprise the following steps：Step 1：One point O is connected in build three machine equivalence system models by three-line with three side power supplys；Step 2：Any both sides equivalent potential is obtained according to the phase relation of each side equivalent source potential oscillations initial time Phase angle difference；Step 3：O point current equations are listed according to Kirchhoff's current law (KCL) and are derived from each side current instantaneous value expression formula, And obtain power frequency feature under multi-machine oscillation scene with reference to trigonometric function relation；Step 4：Any point p power frequency feature is analyzed, obtains electric voltage frequency feature under multi-machine oscillation scene, analysis is drawn Electric voltage frequency is distributed and potential phase angle, relative angular speed, the relation of particular location；Step 5：The offset boundary of oscillation center is obtained according to electric voltage frequency consecutive variations process, skew solstics is in step-out The heart；Step 6：If it is violent compared with the change of other bus frequencies at a certain bus, or bus two it is adjacent frequency change section waveform it is anti- To, then illustrate that out-of-step center passes through, then need not carry out oscillation center identification, it is on the contrary then be identified by step 7；Step 7：Detect each side bus frequency, it is consistent if the change of certain both sides frequency and with the change of opposite side frequency on the contrary, if vibrate Center appears in opposite side, and the oscillation center point position of system under multi-machine oscillation scene is determined according to frequency change severe degree Put.
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| CN104091087A (en) * | 2014-07-22 | 2014-10-08 | 武汉大学 | Asynchronous oscillation separation criterion based on bus voltage frequency |
| CN105552881A (en) * | 2015-12-08 | 2016-05-04 | 东北电力大学 | Alternating current system multi-frequency oscillation composite out-of-step separation criterion method based on wide area measurement information |
| CN107134776A (en) * | 2017-06-27 | 2017-09-05 | 华北电力大学 | The centralized positioning of multi frequency system asynchronous oscillation and displacement path tracing system and method |
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| CN104091087A (en) * | 2014-07-22 | 2014-10-08 | 武汉大学 | Asynchronous oscillation separation criterion based on bus voltage frequency |
| CN105552881A (en) * | 2015-12-08 | 2016-05-04 | 东北电力大学 | Alternating current system multi-frequency oscillation composite out-of-step separation criterion method based on wide area measurement information |
| CN107134776A (en) * | 2017-06-27 | 2017-09-05 | 华北电力大学 | The centralized positioning of multi frequency system asynchronous oscillation and displacement path tracing system and method |
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