CN111030112B - Method for judging transient stability of alternating current-direct current hybrid power system containing flexible direct current - Google Patents

Method for judging transient stability of alternating current-direct current hybrid power system containing flexible direct current Download PDF

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CN111030112B
CN111030112B CN202010002792.1A CN202010002792A CN111030112B CN 111030112 B CN111030112 B CN 111030112B CN 202010002792 A CN202010002792 A CN 202010002792A CN 111030112 B CN111030112 B CN 111030112B
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bus
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CN111030112A (en
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许寅
黄天啸
和敬涵
王丰
谢欢
吴翔宇
刘苗
李烜
曹天植
陈星�
张秋芳
陈瑞
罗婧
徐鹏
王炳辉
王晓斐
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North China Electric Power Research Institute Co Ltd
Beijing Jiaotong University
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Beijing Jiaotong University
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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
    • 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
    • H02J3/24—Arrangements for preventing or reducing oscillations of power in networks
    • 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
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Abstract

The invention provides a method for judging the transient stability of an alternating current-direct current hybrid power system containing flexible direct current, which comprises the following steps: establishing an alternating current-direct current hybrid power system mathematical model considering direct current line dynamic and transient response of a voltage source converter; constructing a transient energy function containing flexible direct current of the alternating current-direct current hybrid power system under a structure retention model based on the mathematical model of the alternating current-direct current hybrid power system, and calculating an initial state energy value of the system after the fault according to the transient energy function; calculating a system critical energy value by using an iterative potential energy boundary surface method; and judging the transient stability of the alternating current and direct current hybrid power system containing the flexible direct current according to the initial state energy value of the system after the fault and the critical energy value of the system. The method is based on the transient stability analysis of the alternating current-direct current hybrid system containing the flexible direct current power transmission of the energy function, and can quantitatively judge the stability of the system in real time.

Description

Method for judging transient stability of alternating current-direct current hybrid power system containing flexible direct current
Technical Field
The invention relates to the technical field of media communication, in particular to a method for judging transient stability of an alternating current-direct current hybrid power system containing flexible direct current.
Background
The Voltage Source Converter High Voltage Direct Current (VSC-HVDC) based High Voltage Direct Current (VSC-HVDC) is suitable for both small and large capacity power transmission. VSC-HVDC technique is widely applied to fields such as long-distance large capacity transmission, asynchronous networking, and the influence of energy imbalance and the like caused by its switching transient state action on the system transient state stability is more serious. In order to avoid increasing the safety and stability risk of an alternating current and direct current hybrid power system in the VSC-HVDC transient conversion process, the method has important significance for the research of transient stability evaluation on a two-region alternating current and direct current hybrid interconnected system containing flexible direct current.
The traditional transient stability analysis of the power system mostly adopts a time domain simulation method, and the method has the capabilities of expanding a model and providing accurate stability prediction. However, the time domain simulation method is computationally expensive, time consuming, and lacks information reflecting the degree of system stability. The direct method is another method for analyzing the transient stability of the power system, and the stability of the power system is analyzed from the energy point of view. The direct method of directly performing Transient stability analysis of the power system by using a Transient Energy Function (TEF) has the advantages of small calculation amount, high calculation speed, capability of providing stability margin of the power system and the like compared with a time domain simulation method. At present, the application of a direct method in an alternating current and direct current hybrid power system is still in a starting stage, research on the construction of an energy function of the alternating current and direct current hybrid power system is limited, the power transmitted by a direct current line is mainly equivalent to a constant power load on a bus of a converter, so that the energy function of the alternating current and direct current hybrid power system can be equivalently represented by the energy function of the alternating current system, and a direct current line model constructed by the method is excessively simplified; there is also literature that derives the energy functions of the dc and ac systems, the weighted sum of which is defined as the TEF of the ac/dc hybrid system, which ignores the dynamic problem of the dc line; the Padiyar method ignores the loss of the direct current line, and a TEF analytical expression of the direct current line can be obtained; there is a document that proposes a transient energy function of an ac/dc hybrid power system structure retention model considering the dynamics of a conventional dc transmission line, in which the dc transmission line is modeled in detail as an equivalent dynamic load affected by both the converter bus port voltage and the dc line current. The method researches and evolves the construction of the traditional direct current line energy function, but the construction and research of the flexible direct current (VSC-HVDC) energy function are not complete and need to be studied deeply.
Therefore, a method for quantitatively determining the stability of the ac/dc hybrid power system with the flexible dc in real time is needed.
Disclosure of Invention
The invention provides a method for judging the transient stability of an alternating current-direct current hybrid power system containing flexible direct current, which aims to solve the defects in the prior art.
In order to achieve the purpose, the invention adopts the following technical scheme.
The invention provides a method for judging the transient stability of an alternating current-direct current hybrid power system containing flexible direct current, which comprises the following steps:
establishing an alternating current-direct current hybrid power system mathematical model considering direct current line dynamic and transient response of a voltage source converter;
constructing a transient energy function containing flexible direct current of the alternating current-direct current hybrid power system under a structure retention model based on the mathematical model of the alternating current-direct current hybrid power system, and calculating an initial state energy value of the system after the fault according to the transient energy function;
calculating a system critical energy value by using an iterative potential energy boundary surface method;
and judging the transient stability of the alternating current and direct current hybrid power system containing the flexible direct current according to the initial state energy value of the system after the fault and the critical energy value of the system.
Preferably, the mathematical model of the ac-dc hybrid power system includes: the system comprises an alternating current transmission network model, a load model, a generator model and a voltage source converter equivalent model;
the alternating current transmission network model is shown as the following formula (1):
Figure GDA0003011905600000031
wherein:
Figure GDA0003011905600000032
the load model is shown in the following formula (2):
Figure GDA0003011905600000033
wherein, BkjIs susceptance between nodes kj, GkjIs the conductance between nodes kj, Pk dIs the active power of node k, Qk dIs reactive power of node k, ILkIs the current of line LK, [ phi ]kIs the phase of node k; the generator model is shown in the following formulas (3) and (4):
Figure GDA0003011905600000034
Figure GDA0003011905600000035
wherein t represents time, GiiRepresents the conductance of node i;
the equivalent model of the voltage source converter is shown as the following formulas (5) to (8):
Figure GDA0003011905600000036
Figure GDA0003011905600000041
Figure GDA0003011905600000042
Figure GDA0003011905600000043
wherein, BrjSusceptance, G, of node rjrjIs the conductance of node ij; b isIjSusceptance, G, representing node IjIjRepresenting the susceptance of node Ij; the AC bus in AC transmission network includes n generator buses, m load buses, l converter buses and PLiAnd QLiLoad power on an alternating current bus; peiAnd QeiIs the electromagnetic power of the generator; v. ofj，θjRepresenting the voltage amplitude and phase angle of the ith bus; v. ofj，θjRepresenting the voltage amplitude and phase angle theta of the kth buskj＝θk-θj；k＝n+2,...,n+m+l+1；vj，θjThe voltage amplitude and the phase angle of the j-th bus are represented, wherein j is 1,2, n, i, n + m + l + 1; thetaij＝θi-θj；Yij＝Gij+jBijAs a node admittance matrix, BijAnd GijRespectively representing susceptance and conductance between a bus i and a node j, wherein i ═ n +1 is a balanced node; frequency dependent loading
Figure GDA0003011905600000044
Constant current load of ILK，ILk∠φkAnd a constant power load of
Figure GDA0003011905600000045
The angle is represented, P represents load active power, and Q represents load reactive power; making the network transmission conductance after the conductance transfer in the elimination admittance matrix zero; omegaiThe rotation speed deviation of the ith generator is obtained; deltaiThe power angle of the ith generator is set; pmiConst represents the mechanical power injected by the ith generator; miIs the inertia time constant of the ith generator; m isgiScreening parameters for generator nodes, wherein 1 st to n th buses in the system are generator buses; the (n + 2) th to (n + m + l + 1) th buses are load buses, and m is a generator bus when the buses aregiWhen the bus is a load bus, m is 1gi＝0；vr-VSCAnd vI-VSCRespectively representing line electromotive forces, I, at the AC sides of the rectification and inversion stations of the VSC converterdThe current on a direct current line is shown, and mu is the utilization rate of the SPWM direct current voltage; m is the modulation ratio of the voltage source converter; rdIs the impedance of the direct current transmission line; l isdIs the inductance value of the DC line, vdr-VSCAnd vdI-VSCDirect current voltages of rectification and inversion sides of the voltage source converter are respectively obtained; pdcr-VSC，Qdcr-VSC，PdcI-VSC，QdcI-VSCRespectively representing rectifying buses of voltage source convertersAnd the equivalent active load and reactive load of the inversion bus; the reactive power set value at the rectification side is
Figure GDA0003011905600000051
The reactive power set value of the inversion side is
Figure GDA0003011905600000052
By Pdcr，Qdcr，PdcI，QdcIUniformly representing the equivalent load of a bus port of the converter; v. ofr，vIUniformly representing the AC side voltage of the bus of the converter; thetarjAnd thetarjRespectively, the voltage angle differences between the rectifying bus r and the inverting bus I and the node j.
Preferably, based on the mathematical model of the ac/dc hybrid power system, constructing a transient energy function of the ac/dc hybrid power system containing a flexible dc under a structure retention model, and calculating an initial state energy value of the system after the fault according to the transient energy function, including: the energy function is shown in the following formula (9):
Wc＝Wk+Wp (9)
wherein, WcRepresents the system energy value, i.e. the initial state energy value of the system after the fault, represents WkSystem transient kinetic energy, WpRepresenting the transient potential energy of the system, comprising: potential energy W associated with an ac transmission network1Potential energy W associated with load2Potential energy W associated with the generator3Potential energy W associated with equivalent load of voltage source converter4。
Preferably, the mathematical model of the ac-dc hybrid power system further includes: the LCC converter equivalent model is shown as the following formula (10-12):
Figure GDA0003011905600000053
Figure GDA0003011905600000054
Figure GDA0003011905600000055
vdr-LCCand vdI-LCCRespectively representing the direct-current side voltages of the rectifier and the inverter; k is a radical of1，k2The transformation ratio of the converter transformer at the rectifying side and the inverter side is set; α is the rectifier delay firing angle; γ is the inverter arc-out angle; rcr，RcIRespectively representing equivalent commutation impedance of a rectifying side and an inverting side; l isdFor inductance values of DC transmission lines, IdIs a direct line current; rdIs the impedance of a DC transmission line, vr-LCCAnd vI-LCCRepresenting the line electromotive forces on the ac side of the rectifier station and the inverter station; pdcr-LCC，Qdcr-LCC，PdcI-LCC，QdcI-LCCAnd respectively representing the equivalent active power and the reactive power of the LCC rectifying bus and the inversion bus.
Preferably, the system transient potential energy WpThe method also comprises potential energy W related to the equivalent model of the power grid commutation converter5Said W5As shown in the following formula (13):
Figure GDA0003011905600000061
wherein, BiiSusceptance, v, representing node iiRepresenting the voltage magnitude, θ, of node isijRepresenting the direct phase angle, V, of node ijsi,VsjRespectively representing the voltage amplitude of the node sj;
preferably, the potential energy W associated with the AC transmission network model1As shown in the following formula (14):
Figure GDA0003011905600000062
the potential energy W related to the load model2As shown in the following formula (15):
Figure GDA0003011905600000063
wherein, thetasiIs the phase angle between nodes si;
the potential energy W related to the generator model3As shown in the following formula (16):
Figure GDA0003011905600000064
preferably, the potential energy W associated with the equivalent model of the voltage source converter4The following equation (17) is obtained:
Figure GDA0003011905600000065
wherein v isrAnd vIThe voltage amplitudes of the rectifying bus and the inverting bus are respectively; thetarAnd thetaIThe voltage phase angle, P, of the rectifier bus and the inverter bus respectivelydcr，Qdcr，PdcI，QdcIThe equivalent active and reactive loads of the rectifier bus and the inverter bus are indicated, respectively.
Preferably, solving for W4The numerical calculation process of (2) includes the steps of:
(1) partial differential equation
Figure GDA0003011905600000071
Respectively using U1、U2、U3、U4Indicating, computing a stable equilibrium point SEPx after a system failuresTo obtain the phase angle phi of the bus of the converter at SEPrsAnd phiIsThe bus voltage of the converter is vrsAnd vIs. Order to
Figure GDA0003011905600000072
(2) Selecting a step index h as a constant;
(3) intervals are divided according to the following intervals:
I1＝[θrs,θr] I2＝[θIs,θI]
I3＝[θrs,θr] I4＝[θIs,θI]
wherein, four intervals I1，I2，I3And I4Are each h1，h2，h3，U4. Expressing the k-th lattice of points of each interval as
Figure GDA0003011905600000073
(4) Setting k to be 1 and I to be 1 to carry out initialization calculation, and taking stable direct current after fault as IdAn initial value of (d);
(5) solving for I by algebraic constraints of equations (5) - (8)d: is solved in
Figure GDA0003011905600000074
Time IdValue, set the result to the next IdCalculating the initial value of the calculation, calculating the current value of equation (5) at the k-th iteration
Figure GDA0003011905600000075
Partial differential of formula (II)
Figure GDA0003011905600000076
And will be
Figure GDA0003011905600000077
Add up to UdcIn the above-mentioned manner,
Figure GDA0003011905600000078
representing the energy function of dc1,
Figure GDA0003011905600000079
representing the energy function of DC3, IdRepresents a direct current;
(6) let k be k +1, if k × hValue greater than hiStep 7 is entered; otherwise, returning to the step (5);
(7) if i is less than 4, making i equal to i +1 and k equal to 1, and then returning to the step (5); otherwise, entering the step (8);
(8) the value of the dc component of the energy function is obtained: u shapedcI.e. W4。
Preferably, the system critical energy value is calculated by using an iterative potential energy boundary surface method, which comprises the following steps:
firstly, continuously simulating the fault until the dot product criterion is changed from negative to positive, and taking the critical energy WcrEqual to the maximum potential energy, i.e. Wcr＝WpmaxAccording to WcrDetermining a critical ablation time tcr；
Is at tcrRemoving faults, reducing the step length by half, and re-simulating:
a. if the dot product criterion is not changed from negative to positive when the simulation is carried out to the time T, the calculation is finished, and the W obtained by the last calculation iscrAnd tcrThe final result is obtained;
b. if a certain time t in the simulation processexWhen the dot product criterion is changed from negative to positive, the iteration is simulated to texEnding, taking potential energy WpReaches a first maximum value and kinetic energy WkAt the same time as the first minimum value is reached
Figure GDA0003011905600000081
W ofpAs WcrIf in the interval [0, tex]Inner WpIf there is no maximum, then take texW of timepAs WcrAccording to WcrDetermining tcrAnd returning to the step II;
wherein, the determination of the dot product criterion is carried out according to the potential energy boundary surface corresponding to the generalized potential energy of the following formula (18):
(Pm-Pe)T(δ-δs)＝0 (18)
Pm，Pedelta and deltasRespectively the mechanical power, the electromagnetic power, the power angle of the synchronous generator and the power angle vector at the stable balance point of the system after the faultAnd the dot product criterion is changed from negative to positive, and the operating point escapes from the potential energy boundary surface.
Preferably, the determining the transient stability of the ac/dc hybrid power system including the flexible dc according to the initial state energy value of the system after the fault and the critical energy value of the system includes: judging the transient stability of the alternating current-direct current hybrid power system containing the flexible direct current according to a system stability margin (19) of the following formula, and when the system stability margin delta W is larger than 0, the system is stable; when the system stability margin Δ W is less than 0, the system is unstable:
Figure GDA0003011905600000082
wherein, WcrIs a system critical energy value; wcRepresenting the initial state energy value of the system after the fault; wkRepresenting the transient kinetic energy of the system at the moment to be measured.
The technical scheme provided by the method for judging the transient stability of the alternating current-direct current hybrid power system containing the flexible direct current can be seen that the method is based on the energy function, considers the direct current line dynamic and equivalent modeling based on the voltage source converter, constructs the transient energy function of the whole system under the fault, calculates the critical energy of the system based on the potential energy boundary surface method, performs transient stability analysis on the system, and can quantitatively judge the stability of the system in real time.
Additional aspects and advantages of the invention will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention.
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In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings needed to be used in the description of the embodiments are briefly introduced below, and it is obvious that the drawings in the following description are only some embodiments of the present invention, and it is obvious for those skilled in the art to obtain other drawings based on these drawings without creative efforts.
Fig. 1 is a schematic flow chart of a method for determining transient stability of an ac-dc hybrid power system including a flexible dc in this embodiment;
FIG. 2 is a schematic diagram of an AC/DC hybrid test system;
FIG. 3 is a schematic diagram illustrating a method for calculating an initial state energy value of a system after a fault according to a transient energy function;
FIG. 4 is a schematic diagram illustrating a method for calculating a critical energy value of a system by using an iterative potential boundary surface method.
Detailed Description
Reference will now be made in detail to embodiments of the present invention, examples of which are illustrated in the accompanying drawings, wherein like reference numerals refer to the same or similar elements or elements having the same or similar function throughout. The embodiments described below with reference to the accompanying drawings are illustrative only for the purpose of explaining the present invention, and are not to be construed as limiting the present invention.
As used herein, the singular forms "a", "an", "the" and "the" are intended to include the plural forms as well, unless the context clearly indicates otherwise. It will be further understood that the terms "comprises" and/or "comprising," when used in this specification, specify the presence of stated features, integers, steps, and/or operations, but do not preclude the presence or addition of one or more other features, integers, steps, and/or operations. It will be understood that when an element is referred to as being "connected" or "coupled" to another element, it can be directly connected or coupled to the other element or intervening elements may also be present. Further, "connected" or "coupled" as used herein may include wirelessly connected or coupled. As used herein, the term "and/or" includes any and all combinations of one or more of the associated listed items.
It will be understood by those skilled in the art that, unless otherwise defined, all terms (including technical and scientific terms) used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. It will be further understood that terms, such as those defined in commonly used dictionaries, should be interpreted as having a meaning that is consistent with their meaning in the context of the prior art and will not be interpreted in an idealized or overly formal sense unless expressly so defined herein.
To facilitate understanding of the embodiments of the present invention, the following description will be further explained by taking specific embodiments as examples with reference to the accompanying drawings.
Examples
Fig. 1 is a schematic flow chart of a method for determining transient stability of an ac-dc hybrid power system including a flexible dc in this embodiment, with reference to fig. 1, the method includes:
s1, establishing a mathematical model of the AC-DC hybrid power system considering the DC line dynamic and the transient response of the voltage source converter.
The alternating current-direct current series-parallel connection electric power system mathematical model comprises: the system comprises an alternating current transmission network model, a load model, a generator model and a Voltage Source Converter (VSC) equivalent model;
the alternating current buses in the alternating current transmission network comprise n generator buses, m load buses and l converter buses. The power balance equation on the ith alternating current bus is an alternating current transmission network model as shown in the following formula (1):
Figure GDA0003011905600000111
wherein:
Figure GDA0003011905600000112
PLiand QLiLoad power on an alternating current bus; peiAnd QeiIs the electromagnetic power of the generator; v. ofj，θjThe voltage amplitude and the phase angle of the j-th bus are represented, wherein j is 1, 2. Thetaij＝θi-θj；Yij＝Gij+jBijIs a node admittance matrix, where i n +1 is a balanced node. m isgiScreening parameters for generator nodes, wherein 1 st to n th buses in the system are generator buses; n +2 th to n + mThe + l +1 buses are load buses, and m is a generator bus when the bus is a generator busgiWhen the bus is a load bus, m is 1gi＝0。
The load type on each bus includes frequency dependent load
Figure GDA0003011905600000113
Constant current load ILk∠φkAnd constant power load
Figure GDA0003011905600000114
The constant impedance load of the system is contained in the ac network admittance matrix. The power flow equation of the load on the kth bus can be expressed as a load model as shown in the following equation (2):
Figure GDA0003011905600000115
wherein, thetakIs the kth bus voltage phase angle; thetakj＝θk-θj(ii) a k ═ n +2,.., n + m + l + 1; assume that the network transmission conductance is zero after eliminating the transfer conductance in the admittance matrix.
The dynamic equation of the ith generator can be expressed as a generator model as shown in the following equations (3) and (4):
Figure GDA0003011905600000116
Figure GDA0003011905600000117
ωithe rotation speed deviation of the ith generator is obtained; deltaiThe power angle of the ith generator is set; pmiConst represents the mechanical power injected by the ith generator; peiIs the electromagnetic power of the generator; miIs the inertia time constant of the ith generator.
Pdcr-VSC，Qdcr-VSC，PdcI-VSC，QdcI-VSCRespectively represent VAnd the SC converter rectifies the equivalent active load and reactive load of the bus and the inversion bus. Considering DC line dynamics, Pdcr-VSC，Qdcr-VSC，PdcI-VSC，QdcI-VSCThe equivalent model of the VSC converter can be shown as the following formula (5-8):
Figure GDA0003011905600000121
wherein v isr-VSCAnd vI-VSCRespectively representing line electromotive forces of alternating current sides of a rectification station and an inversion station of the VSC; i isdIs the current on the direct current line; mu is the SPWM direct-current voltage utilization rate;Mis the modulation ratio of the voltage source converter.
The dynamic characteristics of the dc link are described as:
Figure GDA0003011905600000122
wherein L isdIs a dc line inductance value; rdIs the impedance of the direct current transmission line; v. ofdr-VSCAnd vdI-VSCThe direct current voltage of the rectification side and the inversion side of the voltage source converter is respectively.
For the converter bus, the power balance equation of the rectifying bus r is shown in (7), and the power balance equation of the inverting bus I is shown in (8).
Figure GDA0003011905600000123
Figure GDA0003011905600000124
Wherein, BrjAnd BIjRespectively representing susceptances between a rectifying bus r and an inverting bus I and a node j; grj，GIjRespectively representing the conductance between the rectifying bus r and the node j and the conductance between the inverting bus I and the node j; thetarjAnd thetarjRespectively representing the voltage phase angle difference between the rectifying bus r and the node j and between the inverting bus I and the node j; by usingPdcr，Qdcr，PdcI，QdcIThe equivalent loads of the LCC and VSC bus ports are uniformly expressed.
The mathematical model of the alternating current-direct current hybrid power system can also comprise a power grid Commutated Converter (LCC) equivalent model, Pdcr-LCC，Qdcr-LCC，PdcI-LCC，QdcI-LCCThe equivalent active load and reactive load on the rectifier bus side and the inverter bus side are respectively shown. Considering DC line dynamics, Pdcr-LCC，Qdcr-LCC，PdcI-LCC，QdcI-LCCThe LCC converter equivalent model can be expressed as shown in the following equation (9-11):
Figure GDA0003011905600000131
k1，k2representing the transformation ratio of the converter transformer on the rectifying side and the converter transformer on the inverting side; v. ofr-LCCAnd vI-LCCRepresenting the line electromotive forces on the ac side of the rectifier station and the inverter station; alpha is the delay trigger angle of the rectifier; gamma is an inverter arc-extinguishing angle; rcr，RcIThe equivalent commutation impedances on the rectifying side and the inverting side are shown, respectively.
The dynamic characteristics of the dc link are described as:
Figure GDA0003011905600000132
wherein L isdAn inductance value of the direct current transmission line; i isdIs the current on the direct current line; rdIs the impedance of the direct current transmission line; v. ofdr-LCCAnd vdI-LCCRepresenting the rectifier and inverter dc side voltages, respectively, which are defined as:
Figure GDA0003011905600000133
s2, based on the mathematical model of the AC/DC hybrid power system, a transient energy function of the AC/DC hybrid power system containing flexible direct current under a structure retention model is constructed, and the initial state energy value of the system after the fault is calculated according to the transient energy function.
Transient stability refers to the ability to reach a new stable operating state or to recover to the original state through a transient process after a sudden large disturbance occurs under certain operating conditions. And comparing the initial state energy value of the system after the fault with the critical energy value of the system by using an energy function method, and further judging the stability degree of the system. The energy of the initial state after the fault comprises transient potential energy and transient kinetic energy when the system fault is cleared.
The energy function is shown in equation (12) below:
Wc＝Wk+Wp (12)
wherein, WcRepresents the system energy value, i.e. the initial state energy value of the system after the fault, represents WkSystem transient kinetic energy, WpRepresenting the transient potential energy of the system, comprising: potential energy W associated with an ac transmission network1Potential energy W associated with load2Potential energy W associated with the generator3Potential energy W related to VSC converter equivalent load4。
The kinetic energy of the system is proportional to the square of the rotational speed deviation and is described as follows:
Figure GDA0003011905600000141
transient potential energy W of systempAccording to the LCC converter equivalent model in the mathematical model of the system, the system also comprises potential energy W related to the LCC converter equivalent model5Said W5As shown in the following formula (14):
Figure GDA0003011905600000142
potential energy W associated with an AC transmission network model1As shown in the following formula (15):
Figure GDA0003011905600000143
the potential energy W related to the load model2As shown in the following formula (16):
Figure GDA0003011905600000144
the potential energy W related to the generator model3As shown in the following formula (17):
Figure GDA0003011905600000151
potential energy W related to VSC converter equivalent model4The following equation (18) is obtained:
Figure GDA0003011905600000152
wherein v isrAnd vIThe voltage amplitudes of the rectifying bus and the inverting bus are respectively; thetarAnd thetaIThe voltage phase angle, P, of the rectifier bus and the inverter bus respectivelydcr，Qdcr，PdcI，QdcIThe equivalent active and reactive loads of the rectifier bus and the inverter bus are indicated, respectively.
Solving for W4The numerical calculation process of (2) includes the steps of:
(1) partial differential equation
Figure GDA0003011905600000153
Respectively using U1、U2、U3、U4Indicating, computing a stable equilibrium point SEPx after a system failures(δs,ωs,vs,θs) To obtain the phase angle phi of the bus of the converter at SEPrsAnd phiIsThe bus voltage of the converter is vrsAnd vIsLet us order
Figure GDA0003011905600000154
(2) Selecting a step index h as a constant;
(3) intervals are divided according to the following intervals:
I1＝[θrs,θr] I2＝[θIs,θI]
I3＝[θrs,θr] I4＝[θIs,θI]
wherein h is1，h2，h3，U4Respectively, the lengths of the four intervals. Representing the k-th lattice of points of each interval as Ii k，i＝1,2,3,4；
(4) Setting k to be 1 and I to be 1 to carry out initialization calculation, and taking stable direct current after fault as IdAn initial value of (d);
(5) solving for I by algebraic constraints of equations (5-8)d: is solved in
Figure GDA0003011905600000155
Time IdValue, set the result to the next IdThe initial value of the calculation is calculated by the formula (5)
Figure GDA0003011905600000156
Partial differential of formula (II)
Figure GDA0003011905600000157
And will be
Figure GDA0003011905600000158
Add up to UdcThe above step (1);
(6) let k equal k +1 if k × h is greater than hiStep 7 is entered; otherwise, returning to the step (5);
(7) if i is less than 4, making i equal to i +1 and k equal to 1, and then returning to the step (5); otherwise, entering the step (8);
(8) the value of the dc component of the energy function is obtained: u shapedcI.e. W4。
S3 calculates the system critical energy value by using an iterative potential energy boundary surface method.
And (4) as the amplitude and the phase angle of the bus voltage of the direct current port change in each interval, the residual grid variables including the amplitude and the phase angle of the bus voltage are not changed in size during calculation.
And calculating the critical energy of the system by using an iterative potential energy boundary surface method. And comparing the energy of the initial state after the fault with the critical energy of the system, giving a result of the stability margin of the system, and quantitatively analyzing the stability of the alternating current-direct current hybrid power system.
The system critical energy value is the potential energy maximum value of the system after the fault, and the determination of solving the critical energy value is related to the selection of the system potential energy boundary. (suppose 0s fails and the simulation duration is T.)
Continuing fault simulation, changing the point product criterion from negative to positive, and taking critical energy WcrEqual to the maximum potential energy, i.e. Wcr＝WpmaxAccording to WcrDetermining a critical ablation time tcr；
Is at tcrRemoving faults, reducing the step length by half, and re-simulating:
a. if the dot product criterion is not changed from negative to positive when the simulation is carried out to the time T, the calculation is finished, and the W obtained by the last calculation iscrAnd tcrThe final result is obtained;
b. if a certain time t in the simulation processexWhen the dot product criterion is changed from negative to positive, the iteration is simulated to texEnding, taking potential energy WpReaches a first maximum value and kinetic energy WkAt the same time as the first minimum value is reached
Figure GDA0003011905600000161
W ofpAs WcrIf in the interval [0, tex]Inner WpIf there is no maximum, then take texW of timepAs WcrAccording to WcrDetermining tcrAnd returning to the step II;
wherein, the determination of the dot product criterion is carried out according to the potential energy boundary surface corresponding to the generalized potential energy of the following formula (19):
(Pm-Pe)T(δ-δs)＝0(19)
Pm，Pe，δ，δsthe point product criterion is changed from negative to positive, and the operating point escapes from a potential energy boundary surface.
And S4, judging the transient stability of the alternating current and direct current hybrid power system containing the flexible direct current according to the initial state energy value of the system after the fault and the critical energy value of the system.
Judging the transient stability of the alternating current-direct current hybrid power system containing the flexible direct current according to the system stability margin (20) of the following formula, and when the system stability margin delta W is larger than 0, the system is stable; when the system stability margin Δ W is less than 0, the system is unstable:
Figure GDA0003011905600000171
wherein, WcrIs a system critical energy value; wcRepresenting the initial state energy value of the system after the fault; wkRepresenting the transient kinetic energy of the system at the moment to be measured.
Further, the stability of the system is defined according to the following:
Figure GDA0003011905600000172
fig. 2 is a schematic diagram of an ac/dc hybrid test system, and the method of the present embodiment is applied to the test system shown in fig. 1 to perform a simulation experiment, specifically, the following contents are included:
in the test system shown in fig. 2, there are a total of 241 nodes, including three partitioned communication systems. The test system has 52 generator nodes and 140 load nodes. 7 LCC-HVDC double-circuit direct current lines and 1 VSC-HVDC direct current line, and 30 direct current nodes are total. And after the test scene is an extreme event, judging the transient stability of the AC/DC hybrid large power grid containing the flexible direct current. The points of failure within the system are located between nodes 8-15 and nodes 20-87, respectively, and the failure has been isolated.
Establishing an alternating current-direct current hybrid power system mathematical model considering direct current line dynamics and transient response of a voltage source converter according to information and scene information of the test system shown in FIG. 2; constructing a transient energy function containing flexible direct current of the alternating current-direct current hybrid power system under a structure retention model based on the mathematical model of the alternating current-direct current hybrid power system, and calculating an initial state energy value of the system after the fault according to the transient energy function; calculating a system critical energy value by using an iterative potential energy boundary surface method; and judging the transient stability of the alternating current and direct current hybrid power system containing the flexible direct current according to the initial state energy value of the system after the fault and the critical energy value of the system. A schematic diagram of a method for calculating an initial state energy value of a system after a fault according to a transient energy function is shown in fig. 3, and a schematic diagram of a method for calculating a critical energy value of a system by using an iterative potential energy boundary surface method is shown in fig. 4. The results of the solution are shown in tables 1 and 2 below. Through calculation, the critical ablation time under the scene one obtained by applying an energy function method is 0.10027s, the critical ablation time obtained by adopting the existing time domain simulation method is 0.08s, and the error is about 0.02 s. Under the second scenario, the system critical ablation time obtained by the energy function method is 0.10027s, the critical ablation time calculated by the time domain simulation method is 0.10s, and the error is about 0.0002 s. The system stability margin can be obtained according to an energy function method, the stability margin value under different resection time is reduced along with the delay of the resection time, and the system instability degree is improved.
TABLE 1 Critical excision time comparison of test systems using different methods
Figure GDA0003011905600000181
TABLE 2 transient stability analysis of test systems under different scene systems
Figure GDA0003011905600000182
Those of ordinary skill in the art will understand that: the drawings are merely schematic representations of one embodiment, and the flow charts in the drawings are not necessarily required to practice the present invention.
From the above description of the embodiments, it is clear to those skilled in the art that the present invention can be implemented by software plus necessary general hardware platform. Based on such understanding, the technical solutions of the present invention may be embodied in the form of a software product, which may be stored in a storage medium, such as ROM/RAM, magnetic disk, optical disk, etc., and includes instructions for causing a computer device (which may be a personal computer, a server, or a network device, etc.) to execute the method according to the embodiments or some parts of the embodiments.
The above description is only for the preferred embodiment of the present invention, but the scope of the present invention is not limited thereto, and any changes or substitutions that can be easily conceived by those skilled in the art within the technical scope of the present invention are included in the scope of the present invention. Therefore, the protection scope of the present invention shall be subject to the protection scope of the claims.

Claims (6)

1. A method for judging the transient stability of an alternating current-direct current hybrid power system containing flexible direct current is characterized by comprising the following steps:
establishing an alternating current-direct current hybrid power system mathematical model considering direct current line dynamic and transient response of a voltage source converter;
based on the mathematical model of the alternating current-direct current hybrid power system, constructing a transient energy function of the alternating current-direct current hybrid power system containing flexible direct current under a structure retention model, and calculating an initial state energy value of the system after the fault according to the transient energy function, wherein the method comprises the following steps: the energy function is shown in the following formula (9):
Wc＝Wk+Wp (9)
wherein, WcRepresenting the system energy value, i.e. the post-fault system initial state energy value, WkRepresenting the transient kinetic energy of the system, WpRepresents the transient potential energy of the system, soThe system transient potential energy WpThe method also comprises potential energy W related to the equivalent model of the power grid commutation converter5Said W5As shown in the following formula (13):
Figure FDA0003124997610000011
wherein, BiiRepresenting susceptance of node i, BijRepresenting susceptance, v, between nodes i and jiRepresenting the voltage magnitude, θ, of node isijRepresenting the direct phase angle, v, of node ijsi,vsjRespectively representing the voltage amplitudes, theta, of nodes si, sjijDenotes the phase angle difference between ij, θij＝θi-θj，θjRepresenting the phase angle, θ, of the j-th busiRepresenting the phase angle of the ith bus, wherein the alternating current buses in the alternating current transmission network comprise n generator buses, m load buses and l converter buses;
calculating a system critical energy value by using an iterative potential energy boundary surface method;
judging the transient stability of the AC-DC hybrid power system containing the flexible direct current according to the initial state energy value of the system after the fault and the critical energy value of the system, wherein the transient stability comprises the following steps: judging the transient stability of the alternating current-direct current hybrid power system containing the flexible direct current according to a system stability margin (19) of the following formula, and when the system stability margin delta W is larger than 0, the system is stable; when the system stability margin Δ W is less than 0, the system is unstable:
Figure FDA0003124997610000021
wherein, WcrIs a system critical energy value; wcRepresenting the initial state energy value of the system after the fault; wkRepresenting the transient kinetic energy of the system at the moment to be measured;
the alternating current-direct current series-parallel connection electric power system mathematical model comprises: the system comprises an alternating current transmission network model, a load model, a generator model and a voltage source converter equivalent model;
the alternating current transmission network model is shown as the following formula (1):
Figure FDA0003124997610000022
Figure FDA0003124997610000023
Peiand QeiFor generator electromagnetic power, GijRepresenting the conductance between bus i and node j, where i ═ n +1 is the balanced node, PLiAnd QLiFor the load power on the AC bus, mgiScreening parameters for generator nodes, wherein 1 st to n th buses in the system are generator buses; the (n + 2) th to (n + m + l + 1) th buses are load buses, and m is a generator bus when the buses aregiWhen the bus is a load bus, m is 1gi＝0，vjRepresenting the voltage amplitude of the j bus;
the load model is shown in the following formula (2):
Figure FDA0003124997610000024
wherein the frequency dependent load
Figure FDA0003124997610000025
BkjIs susceptance between nodes kj, GkjIs the conductance between the nodes kj,
Figure FDA0003124997610000026
is the active power of the node k and,
Figure FDA0003124997610000027
is reactive power of node k, ILkIs the current of line LK, [ phi ]kIs the phase of node k, θkDenotes the kth motherPhase angle of voltage of line, thetakj＝θk-θj，k＝n+2,...,n+m+l+1；
The generator model is shown in the following formulas (3) and (4):
Figure FDA0003124997610000031
Figure FDA0003124997610000032
Figure FDA0003124997610000033
wherein M isiIs the inertia time constant of the ith generator; t represents time, GiiDenotes the conductance of node i, MiRepresenting the generator i inertia time constant, ωiRepresenting the speed of rotation, delta, of the generator iiRepresenting the power angle, P, of the generator imiConst represents the mechanical power injected by the ith generator;
the equivalent model of the voltage source converter is shown as the following formulas (5) to (8):
Figure FDA0003124997610000034
Pdcr-VSC，Qdcr-VSCrespectively representing the equivalent active and reactive loads, P, of the rectifying bus of the voltage source converterdcI-VSC，QdcI-VSCRespectively representing equivalent active load and reactive load of an inversion bus of the voltage source converter; the initial value of the reactive power at the rectifying side is set to be
Figure FDA0003124997610000035
The reactive power at the inverter side is set to be an initial value
Figure FDA0003124997610000036
vr-VSCAnd vI-VSCRespectively representing line electromotive forces, I, at the AC sides of the rectification and inversion stations of the VSC converterdThe current on a direct current line is M is the modulation ratio of a voltage source converter, and mu is the utilization ratio of the SPWM direct current voltage;
Figure FDA0003124997610000037
Rdis the impedance of the direct current transmission line; l isdIs the inductance value of the DC line, vdr-VSCAnd vdI-VSCDirect current voltages of rectification and inversion sides of the voltage source converter are respectively obtained;
Figure FDA0003124997610000041
Brjsusceptance, G, of node rjrjIs the conductance of node ij, j 1,2rjRepresents the voltage angle difference between the rectifying bus r and the node j, vrRepresenting the AC side voltage of the converter bus;
Figure FDA0003124997610000042
wherein, BIjSusceptance, G, representing node IjIjRepresenting the susceptance of node Ij; y isij＝Gij+jBijIs a node admittance matrix; making the transmission conductance of the network after the transfer conductance in the elimination admittance matrix zero; pdcr，Qdcr，PdcI，QdcIRepresenting the equivalent active and reactive loads, v, of the rectifier and inverter buses, respectivelyITo invert the voltage amplitude of the bus, thetaIjRepresenting the voltage phase angle difference between inverting bus I and node j.
2. The method of claim 1, wherein the mathematical model of the AC/DC hybrid power system further comprises: the LCC converter equivalent model is shown as the following formula (10-12):
Figure FDA0003124997610000043
vr-LCCand vI-LCCRepresenting the line electromotive forces on the ac side of the rectifier station and the inverter station; pdcr-LCC，Qdcr-LCC，PdcI-LCC，QdcI-LCCRespectively representing the equivalent active power and reactive power of the LCC rectification and inversion buses, IdIs the current on the direct current line, gamma is the inverter arc-quenching angle; rcr，RcIRespectively representing equivalent commutation impedance of a rectifying side and an inverting side; k is a radical of1，k2The transformation ratio of the converter transformer at the rectifying side and the inverter side is alpha, which is the delay trigger angle of the rectifier;
Figure FDA0003124997610000044
Figure FDA0003124997610000051
Ldfor inductance values, R, of DC transmission linesdIs the impedance of the direct current transmission line.
3. The method of claim 1, wherein the system transient potential energy comprises: potential energy W associated with an ac transmission network1Potential energy W associated with load2Potential energy W associated with the generator3Potential energy W associated with equivalent load of voltage source converter4Wherein the potential energy W associated with the AC transmission network model1As shown in the following formula (14):
Figure FDA0003124997610000052
the AC bus in AC transmission network comprises n generator buses, m load buses, l converter buses and vsiRepresenting the magnitude of the voltage, v, at node siiRepresenting the voltage magnitude, θ, of node isijRepresenting the direct phase angle, v, of node ijjIndicating the voltage amplitude, theta, of the j-th busijDenotes the phase angle difference between ij, BiiRepresenting susceptance of node i, BijRepresents the susceptance between nodes i and j;
the potential energy W related to the load model2As shown in the following formula (15):
Figure FDA0003124997610000053
wherein, thetasiIs the phase angle between nodes si, PLiAnd QLiIs the load power on the AC bus, thetaiRepresenting the phase angle of the ith bus;
the potential energy W related to the generator model3As shown in the following formula (16):
Figure FDA0003124997610000054
Pmiconst represents the injection of mechanical power by the ith generator.
4. The method of claim 1, wherein the system transient potential energy comprises: potential energy W associated with an ac transmission network1Potential energy W associated with load2Potential energy W associated with the generator3Potential energy W associated with equivalent load of voltage source converter4Wherein the potential energy W associated with the equivalent model of the voltage source converter4The following equation (17) is obtained:
Figure FDA0003124997610000061
wherein v isrAnd vIThe voltage amplitudes of the rectifying bus and the inverting bus are respectively; thetarAnd thetaIThe voltage phase angle, P, of the rectifier bus and the inverter bus respectivelydcr，Qdcr，PdcI，QdcIThe equivalent active and reactive loads of the rectifier bus and the inverter bus are indicated, respectively.
5. The method of claim 4, wherein W is4The calculation process of the solution value comprises the following steps:
(1) partial differential equation
Figure FDA0003124997610000062
Respectively using U1、U2、U3、U4Indicating, computing a stable equilibrium point SEPx after a system failuresObtaining the phase angle theta of the converter bus at SEPrsAnd phiIsThe bus voltage of the converter is vrsAnd vIsLet us order
Figure FDA0003124997610000063
(2) Selecting a step index h as a constant;
(3) intervals are divided according to the following intervals:
Figure FDA0003124997610000064
Figure FDA0003124997610000065
wherein, four intervals I1，I2，I3And I4Are each h1，h2，h3，h4Each zone is divided intoThe kth lattice of points in between is represented as
Figure FDA0003124997610000066
i＝1,2,3,4；
(4) Setting k to be 1 and I to be 1 to carry out initialization calculation, and taking stable direct current after fault as IdAn initial value of (d);
(5) solving for I by algebraic constraints of equations (5) - (8)d: is solved in
Figure FDA0003124997610000067
Time IdValue, set the result to the next IdCalculating the initial value of the calculation, calculating the current value of equation (5) at the k-th iteration
Figure FDA0003124997610000068
Partial differential of formula (II)
Figure FDA0003124997610000069
And will be
Figure FDA00031249976100000610
Add up to UdcIn the above-mentioned manner,
Figure FDA00031249976100000611
representing the energy function of dc1,
Figure FDA0003124997610000071
representing the energy function of DC3, IdRepresents a direct current;
(6) let k equal k +1 if k × h is greater than hiStep 7 is entered; otherwise, returning to the step (5);
(7) if i is less than 4, making i equal to i +1 and k equal to 1, and then returning to the step (5); otherwise, entering the step (8);
(8) the value of the dc component of the energy function is obtained: u shapedcI.e. W4。
6. The method of claim 1, wherein calculating the system critical energy value using an iterative potential energy boundary surface method comprises:
continuing fault simulation, changing the point product criterion from negative to positive, and taking critical energy WcrEqual to the maximum potential energy, i.e. Wcr＝WpmaxAccording to WcrDetermining a critical ablation time tcr；
Is at tcrRemoving faults, reducing the step length by half, and re-simulating:
a. if the dot product criterion is not changed from negative to positive when the simulation is carried out to the time T, the calculation is finished, and the W obtained by the last calculation iscrAnd tcrThe final result is obtained;
b. if a certain time t in the simulation processexWhen the dot product criterion is changed from negative to positive, the iteration is simulated to texEnding, taking potential energy WpReaches a first maximum value and kinetic energy WkAt the same time as the first minimum value is reached
Figure FDA0003124997610000072
W ofpAs WcrIf in the interval [0, tex]Inner WpIf there is no maximum, then take texW of timepAs WcrAccording to WcrDetermining tcrAnd returning to the step II;
wherein, the determination of the dot product criterion is carried out according to the potential energy boundary surface corresponding to the generalized potential energy of the following formula (18):
(Pm-Pe)T(δ-δs)＝0 (18)
Pm，Pedelta and deltasThe mechanical power, the electromagnetic power and the power angle of the synchronous generator and the power angle vector at the stable balance point of the system after the fault are respectively, the dot product criterion is changed from negative to positive, and the operating point overflows a potential energy boundary surface.
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* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN111786386B (en) * 2020-07-15 2021-09-07 华北电力大学 Control system and method for preventing direct current blocking based on transient energy method
CN112165114B (en) * 2020-10-12 2022-09-23 华北电力大学 Alternating current-direct current hybrid system transient stability analysis method considering commutation failure
CN112734155B (en) * 2020-11-24 2023-10-31 国家电网公司华中分部 Power transmission network risk assessment optimization method based on transient energy unbalance
CN113552430B (en) * 2021-06-22 2023-06-20 南方电网科学研究院有限责任公司 Method and device for judging transient stability of converter based on critical index
CN114336570A (en) * 2021-11-18 2022-04-12 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 instability determination method for double-loop bipolar 12-pulse current converter direct-current power transmission system
CN114744584A (en) * 2022-02-16 2022-07-12 华北电力大学 Dynamic energy gradient-based transient control method and device for direct current receiving end system
CN114629126B (en) * 2022-04-18 2024-04-26 广东电网有限责任公司电力调度控制中心 Control method and system for two-area system through alternating current and multi-circuit direct current interconnection
CN116231720B (en) * 2023-03-28 2023-10-27 山东大学 Method and system for improving transient stability of new energy through flexible direct current grid-connected system
CN117728405B (en) * 2024-02-05 2024-05-03 国网冀北电力有限公司 Power system situation awareness method and device based on hybrid learning network large model

Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN104242305A (en) * 2014-09-11 2014-12-24 清华大学 Transient stability energy function analytical method for power system including new energy
CN106385053A (en) * 2016-11-21 2017-02-08 南方电网科学研究院有限责任公司 Wind power limit penetration power optimization method and device
CN107330193A (en) * 2017-07-01 2017-11-07 南京理工大学 The transient energy function method of meter and VSG inverter current amplitude limits
CN109494765A (en) * 2018-11-13 2019-03-19 北京交通大学 Alternating current-direct current combined hybrid system transient stability control method based on EEAC

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN104242305A (en) * 2014-09-11 2014-12-24 清华大学 Transient stability energy function analytical method for power system including new energy
CN106385053A (en) * 2016-11-21 2017-02-08 南方电网科学研究院有限责任公司 Wind power limit penetration power optimization method and device
CN107330193A (en) * 2017-07-01 2017-11-07 南京理工大学 The transient energy function method of meter and VSG inverter current amplitude limits
CN109494765A (en) * 2018-11-13 2019-03-19 北京交通大学 Alternating current-direct current combined hybrid system transient stability control method based on EEAC

Non-Patent Citations (3)

* Cited by examiner, † Cited by third party
Title
Transient Stability Analysis of AC-DC Hybrid Power Systems Using Direct Method;Xing Chen et al.;《2018 IEEE 2nd International Electrical and Energy Conference》;20190627;参见第76-79页 *
基于端口能量的含VSC-HVDC的交直流混合系统暂态稳定评估;陈厚合等;《电工技术学报》;20180228;第33卷(第3期);全文 *
基于能量函数法的电力系统暂态电压稳定域研究;詹富均;《中国优秀硕士学位论文全文数据库 工程科技Ⅱ辑》;20180715;全文 *

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