CN108988320A - Electrical Power System Dynamic element responds characteristic is to Enhancement of Transient Voltage Stability impact analysis method - Google Patents
Electrical Power System Dynamic element responds characteristic is to Enhancement of Transient Voltage Stability impact analysis method Download PDFInfo
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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
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Abstract
The invention discloses a kind of Electrical Power System Dynamic element responds characteristics to Enhancement of Transient Voltage Stability impact analysis method.In order to study generator, the main influence of HVDC transmission system (HVDC) and induction conductivity on Enhancement of Transient Voltage Stability, from the angle of broad sense branch potential energy, new analysis method is proposed to study influence of the above-mentioned main dynamic element to Enhancement of Transient Voltage Stability.The information of the changing rule and stability margin that are distributed according to transient potential energy in network after failure is basic variable with the idle recovery characteristics of dynamic element each after failure, establishes evaluation index, and then to causing power grid transient voltage instability Mechanism to analyze.Finally, carried out emulation testing using three machines, nine node ac and dc systems on MATLAB and PSAT software platform, the results showed that the feasibility and validity of this method.
Description
Technical field
The present invention relates to power grid Enhancement of Transient Voltage Stability impact analysis technical fields, and in particular to including high-voltage dc transmission
The dynamic elements such as electricity, generator, induction conductivity are to power grid Enhancement of Transient Voltage Stability impact analysis, and further to electric system
Transient voltage instability Mechanism is analyzed after failure.
Background technique
It is continuously increased with number is returned as the receiving end power grid direct current feed-in of representative using the Yangtze River Delta and Pearl River Delta, dc power feed-in
Specific gravity constantly increases, and China's power grid will no longer be simple AC network, but becomes the big of nationwide alternating current-direct current interconnection
Type power grid, and complexity incrementally increases.Since large area blackout is sent out successively caused by Voltage Instability or collapse of voltage
It is raw.Domestic and international electric power scholar has to increasingly pay close attention to Voltage-stabilizing Problems.Thyristor is the high-voltage direct current phase of core
Than with conventional AC system, there are many new dynamic characteristics, influence of the idle recovery characteristics to voltage stability after failure is more
For protrusion, as the ratio of direct current feed-in gradually increases, the voltage stability of system will be by bigger influence.How preferably to comment
A series of dynamic elements including DC converter are estimated after a failure to the influence of stability, and guide optimization stability
Method all have realistic meaning.In tradition research thinking, time-domain simulation method is often utilized, is analyzed by changing system parameter
Influence of the dynamic component to power system transient stability, but take a long time.Direct method can be used for analyzing stability with it and provide
The advantages of stability margin, gradually steps into the public visual field, and wherein energy function becomes a kind of important means.Alternating current-direct current mixing
In system, whole system voltage caused by the idle recovery characteristics or induction conductivity unstability of direct current receiving end commutation system is lost
Surely, concrete reason therein is difficult to distinguish.This problem related work achievement is less.And wherein how to construct corresponding evaluation index
It is a problem to distinguish the influence of Different Dynamic element bring.
Summary of the invention
With the increase of electric power networks complexity, after the system failure, the Dynamic- Recovery characteristic of various power equipments will be right
Transient Voltage Stability in Electric Power System brings different influences.The concentrations of post-fault system transient state energy are that system is unstable
The main reason for, the variation of generator energy will be reflected in various local potentials according to the parameter and characteristic of system components and change
In.By the inspiration of above-mentioned thought and transient voltage analysis skill, not homologous ray dynamic element pair is assessed the invention proposes a kind of
The appraisal procedure that Enhancement of Transient Voltage Stability influences.The present invention proposes new analysis side from the angle of broad sense branch potential energy
Method studies the main dynamic element such as generator, HVDC transmission system (HVDC), induction conductivity to Transient Voltage Stability
The influence of property.The information of the changing rule and stability margin that are distributed according to transient potential energy in network after failure, with electricity each after failure
The Dynamic- Recovery characteristic that gas equipment is idle is basic variable, establishes evaluation index, and then to causing power grid transient voltage unstability
Mechanism is analyzed.This method can quantitatively weigh the effect of each dynamic element, the mechanism of resolution system Voltage Instability, to
Instruct system transient modelling voltage stability optimisation strategy.
The purpose of the present invention can be reached by adopting the following technical scheme that:
A kind of Electrical Power System Dynamic element responds characteristic is to Enhancement of Transient Voltage Stability impact analysis method, the analysis method packet
Include the following steps:
S1, mathematical models of power system is established, and is based on Lyapunov's theory, building is able to reflect the system model
Energy function formula；
S2, Enhancement of Transient Voltage Stability judgement are fixed.The present invention is used to be lost by electric system bifurcation condition and heuristic voltage
The constant-energy surface of steady type controlling unstable equilibrium point construction judges Enhancement of Transient Voltage Stability, but is not limited to this kind of method.
The step is specific as follows:
S201, building energy function；
S202, controlling unstable equilibrium point is sought；
S203, transition energy Ucr is sought；
S204, fault clearance moment energy U is sought；
S205, judge fault clearance moment energy U and transition energy Ucr size, face if fault clearance moment energy U is greater than
Boundary energy Ucr, then decision-making system transient voltage unstability；Otherwise, continue to go to next step；
S206, judge whether to encounter singular surface, if so, decision-making system transient voltage unstability, otherwise, it is determined that system is steady
It is fixed.
S3, according to the energy function formula constructed in step S1, extract wherein part relevant to dynamic power element,
Establish the potential energy component function of each dynamic element, wherein dynamic element includes but is not limited to generator, D.C. high voltage transmission system
System, induction conductivity；
During S4, failure, electric system injects big energy to power grid, and generator speed increase causes kinetic energy to increase, therefore
After barrier is removed, total terpene lactones, kinetic energy is gradually converted into the potential energy of each element and transmission line of electricity along electric power networks.With dynamic
The change in oscillation of energy, the potential energy of each dynamic element are gradually increased and also along with certain oscillations.Born potential energy amplification is most
Local energy overshoot by bigger energy impact, will be also more readily formed accordingly in big dynamic element, and then causes herein
It more easily collapses, therefore after can use failure, before potential energy oscillating curve where each dynamic element potential energy maximum value
The potential energy increment of half period wave carrys out simple analysis power grid weak section.
If equipment potential energy component reaches maximum value (or maximum) moment for T after failure2, corresponding moment potential energy component is U2,
In this period, the minimum moment before reaching maximum value is T1, corresponding moment potential energy component is U1, then gesture in this period
It can poor be Δ U=U2-U1。
Evaluation index one: σ1=Δ U/ Δ Q
Evaluation index two: σ2=V (T2)/ΔU
Wherein Δ Q is in the corresponding period, the power equipment idle variation under the influence of Dynamic- Recovery characteristic after a failure
Amount.V(T2) it is the equipment in T2Moment corresponding access bus voltage amplitude.σ1Value is bigger, then means in this period, the electricity
The idle dynamic variation of power equipment keeps potential energy amplification bigger, that is, the energy impact born is bigger, is also more well at this
The amplitude that network is able to bear then more is easy to cause stable condition to destroy here, finally results in system crash；σ2Value get over
It is small, this means that when the equipment is restored after a failure, the suffered energy impact larger moment, accessed bus nodes voltage value
It is still relatively low, that is to say, that be easier to become critical branch herein.It is thereby achieved that homologous ray dynamic element is not to transient state electricity
Press the assessment of stability influence.
Further, there are n generator node, N number of load bus, 2 direct current system converter station bus nodes, and only have
The Electrical Power System Dynamic element mathematical model and energy function formula of 1 balance nodes are as follows:
Quadravalence generator model used are as follows:
Three order induction motor model used are as follows:
The energy function formula are as follows:
U=UAC+UL1+UL2i+Ug+UR+UI+Ud+UDC
Wherein:
And have:
Wherein, subscript i and j represents network bus nodal scheme, i=1,2 ..., n+N+3；J=1,2 ..., n+N+3.
Wherein, ρiIt is to make Bi -1TiThe parameter of positive definite, and to the matrix-vector being arbitrarily not zero, there is xTBi -1Tix>
0, i=1,2 ..., n.C=[C1,…,Cn]T, Ci=[0 l]；
UDC=-VIVRBIR cos(θI-θR)；
In above formula, work as i=1, when 2 ..., n, ωiFor generator speed, δiFor generator amature angle, MiIt is used for generator
Property time constant, PmiFor generator mechanical power, DiFor damped coefficient, E 'qiFor q axis transient potential, XdiFor the transient state of generator
Reactance, X 'diFor the subtranient reactance of generator, T 'doiFor d axis time constant, EfdiFor excitation potential, PeiFor generator
Electromagnetic power, μiFor excitation controller feedback gain, TviFor excitation con-trol time constant, kiFor excitation voltage single order mathematics
In model, the relevant linear coefficient of accessed busbar voltage, liThe control for making generator excitation be positive for access bus i is normal
Number；R subscript represents rectification side variable, and I subscript represents inverter side variable, VRAnd VIAc bus voltage magnitude, PdR+jQdRAnd PdI+
jQdIFor the compensation power of inverter injection；Work as i=n+1, when n+2 ..., n+N+3, T 'doiFor stator open circuit time constant, MiFor
Induction conductivity inertia time constant, E 'LiFor built-in potential amplitude, XrFor rotor windings equivalence leakage reactance, XmIt is anti-for rotor mutual inductance,
XsFor stator winding leakage reactance, X 'iFor transient state reactance, XiFor synchronous reactance, δiFor induction conductivity generator rotor angle, siIt is sliding for induction conductivity
Difference, TmiFor induction conductivity electromagnetic torque, TeiFor machine torque；UACFor AC network potential energy, UL1For static load potential energy, UL2i
To access i-node induction motor load potential energy, UgFor all generator energies of system and URFor DC rectifier side and AC network
Network interface potential energy, UIFor DC inversion side and AC network interface potential energy, UDCThe potential energy between DC network node, UdFor direct current function
Rate exchanges the potential energy component to be formed, ViAnd VjThe respectively voltage magnitude of bus label i and j, θiAnd θjRespectively bus label i
With the voltage phase angle of j, QLiFor the reactive power of the accessed static load of bus marked as i, PLiFor the bus institute marked as i
Access the active power of static load.
The present invention has the following advantages and effects with respect to the prior art:
Angle of the present invention from energy and domain, distribution and propagation characteristic based on energy in electric system, with dynamic element
Idle dynamic characteristic is that interest variable analyzes system transient modelling Voltage Instability influence factor, and this method is compared to time-domain-simulation
Method is capable of providing quantitative nargin information, time-consuming short, can carry out prediction point to transient voltage unstability Correlative Influence Factors in advance
Analysis, and distinguished the influencing characterisitic of a variety of dynamic elements.The present invention provides simple evaluation index, by transient voltage, idle
It combines with energy, Enhancement of Transient Voltage Stability is influenced with each dynamic element of angle comprehensive analysis of system, it on this basis can be with
Further guidance selection voltage optimization measure, for example, the method for directly installing reactive-load compensation equipment additional compared with tradition, the present embodiment is also
Provide an other thinking, it can influence gesture after its failure by improving direct current system relevant parameter when power grid is built
Energy variation tendency, and then Enhancement of Transient Voltage Stability under failure is fundamentally improved, while this method is perhaps also than configuring certain nothing
The economy that function compensates equipment is higher.
Detailed description of the invention
Fig. 1 is Electrical Power System Dynamic element responds characteristic disclosed in the present invention to Enhancement of Transient Voltage Stability impact analysis side
The flow diagram of method；
Fig. 2 is three machines, the nine node system schematic diagram comprising direct current；
Fig. 3 be the fault clearance moment be the part 1.18s bus nodes voltage pattern；
Fig. 4 is that 1.178s removes induction conductivity, direct current potential variation curve graph after failure；
Fig. 5 is that 1.178s removes generator potential variation curve graph after failure；
Fig. 6 is generator's power and angle figure when 1.178s removes failure；
Fig. 7 is that 1.18s removes after failure induction conductivity slippage figure in the case of unstability.
Specific embodiment
In order to make the object, technical scheme and advantages of the embodiment of the invention clearer, below in conjunction with the embodiment of the present invention
In attached drawing, technical scheme in the embodiment of the invention is clearly and completely described, it is clear that described embodiment is
A part of the embodiment of the present invention, instead of all the embodiments.Based on the embodiments of the present invention, those of ordinary skill in the art
Every other embodiment obtained without creative efforts, shall fall within the protection scope of the present invention.
Embodiment
Electrical Power System Dynamic element responds characteristic as shown in Figure 1 is to Enhancement of Transient Voltage Stability impact analysis method process
Scheme, Electrical Power System Dynamic element responds characteristic disclosed in the present embodiment includes following to Enhancement of Transient Voltage Stability impact analysis method
Step:
Step S1, mathematical models of power system is established, and is based on Lyapunov's theory, building is able to reflect the system mould
The energy function formula of type.Obtained energy function formula is as follows:
U=UAC+UL1+UL2i+Ug+UR+UI+Ud+UDC
Wherein:
And have:
Wherein, ρiIt is to make Bi -1TiThe parameter of positive definite, and to the matrix-vector being arbitrarily not zero, there is xTBi -1Tix>
0, i=1,2,3；
C=[C1,…,Cn]T, Ci=[0 l]；
Above formula subscript i and j represent network bus nodal scheme, in the present embodiment, i and j=1, and 2,3 ..., 9, i=1,2,3
When, that is, it has accessed the bus of generator, when i=6, that is, has accessed induction motor load bus, subscript i and j represent network mother
Line nodal scheme.Work as i=1, when 2,3, ωiFor generator speed, δiFor generator amature angle, MiFor generator inertia time
Constant, PmiFor generator mechanical power, DiFor damped coefficient, E 'qiFor q axis transient potential, XdiFor the transient state reactance of generator,
X′diFor the subtranient reactance of generator, T 'doiFor d axis time constant, EfdiFor excitation potential, PeiFor generator electromagnetic work
Rate, μiFor excitation controller feedback gain, TviFor excitation con-trol time constant, kiFor excitation voltage first-order mathematic model
In, the relevant linear coefficient of accessed busbar voltage, liFor the control constant for making generator excitation be positive for accessing bus i；Under R
Mark represents rectification side variable, and I subscript represents inverter side variable, VRAnd VIAc bus voltage magnitude, PdR+jQdRAnd PdI+jQdIFor
The compensation power of inverter injection；As i=6, T 'doiFor stator open circuit time constant, MiIt is normal for induction conductivity inertia time
Number, EL′iFor built-in potential amplitude, XrFor rotor windings equivalence leakage reactance, XmAnti-, the X for rotor mutual inductancesFor stator winding leakage reactance, X 'i
For transient state reactance, XiFor synchronous reactance, δiFor induction conductivity generator rotor angle, siFor induction conductivity slippage, TmiFor induction electric electromechanics
Magnetic torque, TeiFor machine torque；UACFor AC network potential energy, UL1For static load potential energy, UL2iTo access i-node induction electric
Machine load potential energy, UgFor all generator energies of system and URFor DC rectifier side and AC network interface potential energy, UIFor direct current
Inverter side and AC network interface potential energy, UDCThe potential energy between DC network node, UdThe potential energy to be formed point is exchanged for dc power
Amount, ViAnd VjThe respectively voltage magnitude of bus label i and j, θiAnd θjThe respectively voltage phase angle of bus label i and j, QLiFor
Marked as the reactive power of the accessed static load of the bus of i, PLiFor the wattful power of the accessed static load of bus marked as i
Rate.
Step S2, Enhancement of Transient Voltage Stability judgement is fixed.The present invention is used by electric system bifurcation condition and based on inspiration
Formula obtains the constant-energy surface of Voltage Instability type controlling unstable equilibrium point construction to judge Enhancement of Transient Voltage Stability, but does not limit to
In this kind of method.
In the implementation case, bus 5 is in the 1s moment and three phase short circuit fault is arranged, and the 1.18s moment removes, and PSAT is being carried out
It is interrupted when time-domain-simulation, i.e., as Fig. 3 can be obtained, under the failure, transient state running track encounters singular surface after failure, leads to differential generation
Time-domain-simulation under number equation group (DAE) models can not operation, moment energy value is 0.36 after fault clearance at this time, is less than leading
The obtained transition energy of unstable equilibrium point, but under the failure, transient state running track encounters singular surface after failure, causes
Time-domain-simulation under DAE model can not operation, since unusual bifurcation and transient voltage unstability are closely related, this reality
It applies example and is also considered as generation transient voltage unstability.
Step S3, it according to the energy function formula constructed in step S1, extracts wherein relevant to dynamic power element
The potential energy component function of each dynamic element is established in part, wherein dynamic element includes but is not limited to generator, high-voltage dc transmission
Electric system, induction conductivity.
It is expressed as follows by each dynamic element potential energy component function that step S1 is obtained:
Generator potential energy:
Induction conductivity potential energy component:
DC transmission system potential energy component:
Each symbolic representation variable is shown in step S1.By time-domain simulation results can in the hope of each potential energy component value of each time step and
Change curve.
Step S4, during failure, electric system injects big energy to power grid, and generator speed increase causes kinetic energy to increase
Greatly, after fault clearance, total terpene lactones, kinetic energy is gradually converted into the potential energy of each element and transmission line of electricity along electric power networks.
With the change in oscillation of kinetic energy, the potential energy of each dynamic element is gradually increased and also along with certain oscillation.Born potential energy
Local energy overshoot by bigger energy impact, will be also more readily formed accordingly in the maximum dynamic element of amplification, and then leads
It causes to be easier to collapse herein, therefore after can use failure, potential energy oscillation song where each dynamic element potential energy maximum value
The potential energy increment of the preceding half period wave of line carrys out simple analysis power grid weak section.
If equipment potential energy component reaches maximum value (or maximum) moment for T after failure2, corresponding moment potential energy component is U2,
In this period, the minimum moment before reaching maximum value is T1, corresponding moment potential energy component is U1, then gesture in this period
It can poor be Δ U=U2-U1。
Evaluation index one: σ1=Δ U/ Δ Q
Evaluation index two: σ2=V (T2)/ΔU
Wherein Δ Q is in the corresponding period, the power equipment idle variation under the influence of Dynamic- Recovery characteristic after a failure
Amount.V(T2) it is the equipment in T2Moment corresponding access bus voltage amplitude.σ1Value is bigger, then means in this period, the electricity
The idle dynamic variation of power equipment makes potential energy increase speed faster, and amplification is bigger, that is, the energy impact born is bigger, also more
It is well over the amplitude that network at this is able to bear, is then more easy to cause stable condition to destroy here, finally results in system
Collapse；σ2Value it is smaller, this means that at the suffered energy impact larger moment, being accessed when the equipment is restored after a failure
Bus nodes voltage value is still relatively low, that is to say, that is easier to become critical branch herein.
Based on Fig. 2 system, and be in the 1s moment in bus 5 and three phase short circuit fault be set, and respectively at 1.05s, 1.1s,
1.14s, 1.178s remove failure.
It is inscribed when comparing same fault clearance, potential energy oscillation amplification curve (by taking Fig. 4, Fig. 5 as an example) can be obvious after failure
It was found that: direct current system, No. 2 generators are in this period for reaching potential energy maximum value, by the oscillation width of minimum to maximum value
Degree is maximum, is secondly induction motor load, is finally No. 1 generator and No. 3 generators.Simultaneously it has also been discovered that, with from
The increase of fault point electrical distance, each electrical equipment under energy impact, potential energy oscillation maximum amplitude occur time by
Step passage, also side reflects energy propagation characteristic in a network and transient voltage unstability is likely to occur in plurality of pendulums for this
Situation.
1. index of table, one σ1
2. index of table, two σ2
In table 1, one σ of index of direct current system1Respective value is much higher than other equipment, followed by No. 2 generators and induced electricity
Engine load, and it is then minimum away from No. 3 farthest generators of fault point electrical distance.Illustrate the recovery characteristics in each electrical equipment
Under effect, the variation of direct current receiving end commutation system dynamic reactive causes when being impacted by ceiling capacity, the vibration of direct current system potential energy
It swings amplitude and amplification speed is easier to become larger, i.e., be easier in this pendulum so that local energy is excessive, beyond ability to bear at this
And generating system stability is destroyed, and then acceleration system transient voltage collapses.Therefore, the idle recovery of direct current receiving end commutation system
Characteristic is occupied an leading position in the system transient modelling Voltage Instability.
With the increase of fault clearance time, induction motor load and No. 2 one σ of generator index1Absolute value gradually
Increase, and the σ of direct current system1Value has becoming smaller by a small margin.Therefore, the fault clearance time is longer, system each node when failure
Voltage Drop amplitude is bigger, and influence of the part throttle characteristics of induction conductivity to Enhancement of Transient Voltage Stability is gradually increased.And three hairs
In motor, when No. 2 generators are by energy impact, in direct current recovery characteristics, induction machine part throttle characteristics and power transmission network
Under transmission characteristic effect, change for the idle dynamic that supporting network node voltage is formed to itself potential energy oscillation amplitude and frequency shadow
It rings and is higher than other two generators, illustrate after fault clearance, in three generators, be easier that part occurs at No. 2 generators
Energy variation is excessive, if then occur transient voltage unstability, No. 2 generators should be able to two units be early generator rotor angle mistake occurs than other
Surely.Since its No. 2 bus accessed is connected with direct current system, meanwhile, in table 2, No. 2 generators, high-voltage direct current and sense
Two σ of index of induction motor load2Respective value is well below No. 1 generator and No. 3 generators, therefore No. 2 generators, direct current system
System, induction motor load form the voltage tender spots of the electric system.
In addition by data in table 1 and above-mentioned two table, it is apparent that with the fault clearance time increase, when failure
Voltage Drop amplitude is bigger, during failure to system inject energy value it is bigger, then each dynamic element of post-fault system by
Energy impact it is also bigger, No. 2 generators, direct current system, the local energy value gathered at induction motor load also will be more
Greatly, Enhancement of Transient Voltage Stability is lower.
Under stable case (for Fig. 6), the opposite generator rotor angle of No. 2 generators arranges amplitude considerably beyond other two units,
And generator rotor angle is advanced.When transient voltage unstability occurs, although being limited due to encountering singular surface by DAE model, PSAT can not continue
Emulation is gone down, however as can be seen from Figure 7 1.2s when, the slippage of induction machine reaches peak value and has the tendency that reduction, that is, incudes
Induction-motor load rotor has begun acceleration, when illustrating to encounter singular surface, not due to induction conductivity cannot normally accelerate and
Stall occurs, causes induction machine load voltage unstability, whole system collapse of voltage caused by, therefore also side illustration direct current
The dominance that recovery characteristics that receiving end commutation system is idle influence the system transient modelling Voltage Instability.
In conclusion the present invention is electric to transient state in order to study generator, HVDC transmission system (HVDC) and motor
The main influence for pressing stability, from the angle of broad sense branch potential energy, it is above-mentioned main to study to propose new analysis method
Influence of the dynamic element to Enhancement of Transient Voltage Stability.According to the changing rule of transient potential energy distribution in network after failure and stablize abundant
The information of degree is basic variable with the idle Dynamic- Recovery characteristic of electrical equipment each after failure, establishes evaluation index, and then right
Power grid transient voltage instability Mechanism is caused to be analyzed.The result of time-domain-simulation and the method for the present invention analysis result are almost the same,
Demonstrate the validity of this method.
The above embodiment is a preferred embodiment of the present invention, but embodiments of the present invention are not by above-described embodiment
Limitation, other any changes, modifications, substitutions, combinations, simplifications made without departing from the spirit and principles of the present invention,
It should be equivalent substitute mode, be included within the scope of the present invention.
Claims (4)
1. a kind of Electrical Power System Dynamic element responds characteristic is to Enhancement of Transient Voltage Stability impact analysis method, which is characterized in that institute
The analysis method stated includes the following steps:
S1, mathematical models of power system is established, and is based on Lyapunov's theory, building is able to reflect the energy of the system model
Function expression；
S2, Enhancement of Transient Voltage Stability judgement, by electric system bifurcation condition and based on the heuristic Voltage Instability type master acquired
The constant-energy surface of unstable equilibrium point construction is led to judge Enhancement of Transient Voltage Stability；
S3, according to the energy function formula constructed in step S1, extract wherein part relevant to dynamic power element, establish
The potential energy component function of each dynamic element, wherein the dynamic element includes generator, HVDC transmission system, induction
Motor；
During S4, failure, electric system injects big energy to power grid, and generator speed increase causes kinetic energy to increase, and failure is clear
After removing, total terpene lactones, kinetic energy is gradually converted into the potential energy of each element and transmission line of electricity along electric power networks, with kinetic energy
The potential energy of change in oscillation, each dynamic element is gradually increased and also along with certain oscillation, and born potential energy amplification is maximum
Dynamic element utilizes the first half of potential energy oscillating curve where each dynamic element potential energy maximum value for by bigger energy impact
The potential energy increment of a period wave analyzes power grid weak section.
2. Electrical Power System Dynamic element responds characteristic according to claim 1 is to Enhancement of Transient Voltage Stability impact analysis side
Method, which is characterized in that the step S2 process is as follows:
S201, building energy function；
S202, controlling unstable equilibrium point is sought；
S203, transition energy Ucr is sought；
S204, fault clearance moment energy U is sought；
S205, fault clearance moment energy U and transition energy Ucr size are judged, if fault clearance moment energy U is greater than critical energy
Ucr is measured, then decision-making system transient voltage unstability；Otherwise, continue to go to next step；
S206, judge whether to encounter singular surface, if so, decision-making system transient voltage unstability, otherwise, it is determined that system is stablized.
3. Electrical Power System Dynamic element responds characteristic according to claim 1 is to Enhancement of Transient Voltage Stability impact analysis side
Method, which is characterized in that first half week of potential energy oscillating curve where each dynamic element potential energy maximum value in the step S4
The potential energy increment of phase wave analyzes power grid weak section, realizes that homologous ray dynamic element is not to transient state electricity by following evaluation index
The assessment of stability influence is pressed, specific as follows:
It is T at the time of if equipment potential energy component reaches maximum value or maximum after failure2, corresponding moment potential energy component is U2, at this
In one potential fluctuation period, the minimum moment before reaching maximum value is T1, corresponding moment potential energy component is U1, then this is a
Potential energy difference is Δ U=U in the potential fluctuation period2-U1, it is as follows to define evaluation index:
Evaluation index one: σ1=Δ U/ Δ Q
Evaluation index two: σ2=V (T2)/ΔU
Wherein, Δ Q is in the corresponding period, the power equipment idle work variable quantity under the influence of Dynamic- Recovery characteristic after a failure, V
(T2) it is the equipment in T2Moment corresponding access bus voltage amplitude.
4. Electrical Power System Dynamic element responds characteristic according to claim 1 is to Enhancement of Transient Voltage Stability impact analysis side
Method, which is characterized in that the dynamic element mathematical model and energy function formula of electric system are as follows:
Quadravalence generator model used are as follows:
Three order induction motor model used are as follows:
It is described to have n generator node, N number of load bus, 2 direct current system converter station bus nodes, and only 1 balance section
The electric system energy function formula of point are as follows:
U=UAC+UL1+UL2i+Ug+UR+UI+Ud+UDC
Wherein:
And have:
E=[E1,…,En]T, Ei=[E 'qi Efdi]；T=blockdiag [T1,…,Tn],A=
blockdiag[A1,…,An],B=blockdiag [B1,…,Bn],
Wherein, subscript i and j represents network bus nodal scheme, i=1,2 ..., n+N+3, j=1,2 ..., n+N+3, ρiBe in order to
Make Bi -1TiThe parameter of positive definite, and to the matrix-vector being arbitrarily not zero, there is xTBi -1TiX > 0, i=1,2 ..., n；
C=[C1,…,Cn]T, Ci=[0 l]；
UDC=-VIVRBIR cos(θI-θR)；
In above formula, work as i=1, when 2 ..., n, ωiFor generator speed, δiFor generator amature angle, MiFor generator inertial time
Between constant, PmiFor generator mechanical power, DiFor damped coefficient, E 'qiFor q axis transient potential, XdiFor the transient state electricity of generator
It is anti-, X 'diFor the subtranient reactance of generator, T 'doiFor d axis time constant, EfdiFor excitation potential, PeiIt is electromechanical for power generation
Magnetic power, μiFor excitation controller feedback gain, TviFor excitation con-trol time constant, kiFor excitation voltage single order mathematical modulo
In type, the relevant linear coefficient of accessed busbar voltage, liFor the control constant for making generator excitation be positive for accessing bus i；R
Subscript represents rectification side variable, and I subscript represents inverter side variable, VRAnd VIAc bus voltage magnitude, PdR+jQdRAnd PdI+jQdI
For the compensation power of inverter injection；Work as i=n+1, when n+2 ..., n+N+3, T 'doiFor stator open circuit time constant, MiFor sense
Induction motor inertia time constant, E 'LiFor built-in potential amplitude, XrFor rotor windings equivalence leakage reactance, XmAnti-, the X for rotor mutual inductances
For stator winding leakage reactance, X 'iFor transient state reactance, XiFor synchronous reactance, δiFor induction conductivity generator rotor angle, siIt is sliding for induction conductivity
Difference, TmiFor induction conductivity electromagnetic torque, TeiFor machine torque；UACFor AC network potential energy, UL1For static load potential energy, UL2i
To access i-node induction motor load potential energy, UgFor all generator energies of system and URFor DC rectifier side and AC network
Network interface potential energy, UIFor DC inversion side and AC network interface potential energy, UDCThe potential energy between DC network node, UdFor direct current function
Rate exchanges the potential energy component to be formed, ViAnd VjThe respectively voltage magnitude of bus label i and j, θiAnd θjRespectively bus label i
With the voltage phase angle of j, QLiFor the reactive power of the accessed static load of bus marked as i, PLiFor the bus institute marked as i
Access the active power of static load.
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| Publication number | Priority date | Publication date | Assignee | Title |
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| CN110867862A (en) * | 2019-12-20 | 2020-03-06 | 国家电网有限公司 | Power grid transient voltage stability quantitative evaluation method |
| CN111769584A (en) * | 2020-07-15 | 2020-10-13 | 华北电力大学 | Stability evaluation method and system for high-voltage direct current receiving end system |
| CN112557813A (en) * | 2020-11-26 | 2021-03-26 | 国网宁夏电力有限公司电力科学研究院 | Method for judging voltage stability of power grid under simultaneous fault of multiple loops of direct current |
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| CN107069774A (en) * | 2017-04-01 | 2017-08-18 | 华北电力大学 | Power system energy function preferably and transient stability margin assessment system and method |
| JP2017200275A (en) * | 2016-04-26 | 2017-11-02 | 株式会社日立製作所 | Electric power system analyzing system and method |
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| JP2017200275A (en) * | 2016-04-26 | 2017-11-02 | 株式会社日立製作所 | Electric power system analyzing system and method |
| CN107069774A (en) * | 2017-04-01 | 2017-08-18 | 华北电力大学 | Power system energy function preferably and transient stability margin assessment system and method |
Cited By (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN110867862A (en) * | 2019-12-20 | 2020-03-06 | 国家电网有限公司 | Power grid transient voltage stability quantitative evaluation method |
| CN111769584A (en) * | 2020-07-15 | 2020-10-13 | 华北电力大学 | Stability evaluation method and system for high-voltage direct current receiving end system |
| US20220021213A1 (en) * | 2020-07-15 | 2022-01-20 | North China Electric Power University | Method and system for evaluating stability of HVDC receiving end system, and storage medium |
| CN111769584B (en) * | 2020-07-15 | 2022-02-01 | 华北电力大学 | Stability evaluation method and system for high-voltage direct current receiving end system |
| CN112557813A (en) * | 2020-11-26 | 2021-03-26 | 国网宁夏电力有限公司电力科学研究院 | Method for judging voltage stability of power grid under simultaneous fault of multiple loops of direct current |
| CN112557813B (en) * | 2020-11-26 | 2022-07-19 | 国网宁夏电力有限公司电力科学研究院 | Method for judging voltage stability of power grid under simultaneous fault of multiple loops of direct current |
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