CN112765932B - Method and device for analyzing influence of SVG on doubly-fed grid-connected system - Google Patents
Method and device for analyzing influence of SVG on doubly-fed grid-connected system Download PDFInfo
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Abstract
The invention discloses a method and a device for analyzing the influence of SVG on a doubly-fed grid-connected system, wherein the method comprises the following steps: obtaining an equivalent model of SVG and doubly-fed grid-connected system interaction; simplifying the equivalent model into a single-input single-output equivalent complex circuit model; obtaining an influence factor index of SVG additional impedance on a system oscillation mode according to the single-input single-output equivalent complex circuit model; and determining the influence of the SVG on the doubly-fed grid-connected system according to the influence factor index. The invention provides a method for effectively analyzing the influence of SVG on a doubly-fed grid-connected system.
Description
Technical Field
The invention relates to the field of stability analysis of doubly-fed grid-connected systems, in particular to a method and a device for analyzing influence of SVG on a doubly-fed grid-connected system.
Background
Double-fed equipment such as double-fed pumping and accumulating equipment, double-fed wind turbine generators and the like has the characteristics of multi-time scale control links and quick control of power electronic driving equipment, and with the wide use of the double-fed equipment, the operation control between the cluster double-fed equipment and a power grid and between adjacent power electronic driving equipment is mutually coupled and influenced to be outstanding, the double-fed equipment is connected with a main system grid frame through a current transformer, the problem of system voltage stability is outstanding, the oscillation problem of the current transformer grid-connected system can be generally analyzed from a small interference angle, and the method mainly comprises the following two types: characteristic root analysis method based on state space and impedance analysis method based on frequency domain theory. The characteristic root analysis method depends on detailed models and parameters of the converter and the power grid, and is difficult to adapt to large-scale grid-connected analysis of doubly-fed equipment. In comparison, the impedance analysis method regards the converter and the power grid as two independent subsystems, and then judges the stability of the system according to whether the impedance matrixes of the two subsystems meet the Nyquist stability criterion. The impedance matrix used in the impedance method is obtained by measurement, that is, the stability of the system can be quantitatively analyzed by measuring the characteristics outside the ports of the current transformer and the power grid, so that the impedance matrix is widely paid attention.
The SVG (static var generator) can be used for reactive compensation of the doubly-fed grid-connected system, so that voltage support can be provided for the system, and the SVG has the characteristics of strong adjustability, high response speed and high reliability. The control strategy of the currently used SVG (static var generator) mainly adopts fixed reactive power control or fixed alternating voltage control. However, no clear method is available at present for stability analysis of the doubly fed machine set and the grid-connected system of the SVG. In addition, the influence of SVG on the grid-connected system of the doubly-fed device is not theoretically analyzed and explained, so that the small interference stability of the doubly-fed device and the SVG interaction system is difficult to evaluate.
Disclosure of Invention
The invention provides a method and a device for analyzing the influence of SVG on a doubly-fed grid-connected system in order to solve at least one technical problem in the background art.
To achieve the above object, according to one aspect of the present invention, there is provided a method of analyzing an influence of SVG on a doubly-fed grid-connected system, the method comprising:
obtaining an equivalent model of SVG and doubly-fed grid-connected system interaction;
simplifying the equivalent model into a single-input single-output equivalent complex circuit model;
obtaining an influence factor index of SVG additional impedance on a system oscillation mode according to the single-input single-output equivalent complex circuit model;
and determining the influence of the SVG on the doubly-fed grid-connected system according to the influence factor index.
Optionally, the equivalent model is constructed by a generalized impedance and equivalent original-dual circuit analysis method in a small-interference stability analysis.
Optionally, the determining the influence of the SVG on the doubly-fed grid-connected system according to the influence factor index includes:
and determining the influence of the SVG on the stability and the oscillation frequency of the doubly-fed grid-connected system according to the influence factor index.
Optionally, the determining the influence of the SVG on the stability and the oscillation frequency of the doubly-fed grid-connected system according to the influence factor index includes:
if the real part of the influence factor index is positive, determining that SVG is added to reduce the stability of the doubly-fed grid-connected system;
and if the real part of the influence factor index is negative, determining to add SVG to improve the stability of the doubly-fed grid-connected system.
Optionally, the determining the influence of the SVG on the stability and the oscillation frequency of the doubly-fed grid-connected system according to the influence factor index includes:
if the imaginary part of the influence factor index is positive, determining to add SVG to improve the oscillation frequency of the doubly-fed grid-connected system;
and if the imaginary part of the influence factor index is negative, determining to add SVG to reduce the oscillation frequency of the doubly-fed grid-connected system.
Optionally, the resonance zero point of the single-input single-output equivalent complex circuit model is the characteristic root of the equivalent model.
To achieve the above object, according to another aspect of the present invention, there is provided an apparatus for analyzing an influence of SVG on a doubly-fed grid-connected system, the apparatus comprising:
the equivalent model acquisition unit is used for acquiring an equivalent model of interaction of the SVG and the doubly-fed grid-connected system;
the model transformation unit is used for simplifying the equivalent model into a single-input single-output equivalent complex circuit model;
the influence factor index determining unit is used for obtaining an influence factor index of the SVG additional impedance on the system oscillation mode according to the single-input single-output equivalent complex circuit model;
and the influence analysis unit is used for determining the influence of the SVG on the doubly-fed grid system according to the influence factor index.
To achieve the above object, according to another aspect of the present invention, there is also provided a computer device including a memory, a processor, and a computer program stored on the memory and executable on the processor, the processor implementing the steps in the method of analyzing the effect of SVG on a doubly-fed grid-connected system described above when the computer program is executed.
To achieve the above object, according to another aspect of the present invention, there is also provided a computer readable storage medium storing a computer program which, when executed in a computer processor, implements the steps in the method of analyzing the effect of SVG on a doubly-fed grid-connected system described above.
The beneficial effects of the invention are as follows: according to the invention, the equivalent model is simplified into the single-input single-output equivalent complex circuit model, so that the influence factor index of the SVG additional impedance on the system oscillation mode is obtained according to the single-input single-output equivalent complex circuit model, and finally, the influence of the SVG on the doubly-fed grid-connected system can be determined according to the influence factor index, thereby effectively analyzing the influence of the SVG on the doubly-fed grid-connected system.
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In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings that are required in the embodiments or the description of the prior art will be briefly described, and it is obvious that the drawings in the following description are some embodiments of the present invention, and other drawings may be obtained according to these drawings without inventive effort for a person skilled in the art. In the drawings:
FIG. 1 is a flow chart of a method of analyzing the impact of SVG on a doubly-fed grid-tie system in accordance with an embodiment of the present invention;
FIG. 2 is a flow chart of an embodiment of the invention for determining the effect of SVG on the stability of a doubly-fed grid-tie system;
FIG. 3 is a flow chart of an embodiment of the invention for determining the effect of SVG on the oscillation frequency of a doubly-fed grid-tie system;
FIG. 4 is a block diagram of an apparatus for analyzing the effect of SVG on a doubly-fed grid-tie system in accordance with an embodiment of the present invention;
FIG. 5 is an equivalent source-dual circuit of the SVG of the present invention interacting with a doubly-fed grid-tie system;
FIG. 6 is a Thevenin equivalent diagram of a converter and SVG interactive system in simulation verification according to an embodiment of the invention;
FIG. 7 is a schematic diagram of a computer device according to an embodiment of the invention.
Detailed Description
In order that those skilled in the art will better understand the present invention, a technical solution in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in which it is apparent that the described embodiments are only some embodiments of the present invention, not all embodiments. All other embodiments, which can be made by those skilled in the art based on the embodiments of the present invention without making any inventive effort, shall fall within the scope of the present invention.
It will be appreciated by those skilled in the art that embodiments of the present invention may be provided as a method, system, or computer program product. Accordingly, the present invention may take the form of an entirely hardware embodiment, an entirely software embodiment or an embodiment combining software and hardware aspects. Furthermore, the present invention may take the form of a computer program product embodied on one or more computer-usable storage media (including, but not limited to, disk storage, CD-ROM, optical storage, and the like) having computer-usable program code embodied therein.
It is noted that the terms "comprises" and "comprising," and any variations thereof, in the description and claims of the present invention and in the foregoing figures, are intended to cover a non-exclusive inclusion, such that a process, method, system, article, or apparatus that comprises a list of steps or elements is not necessarily limited to those steps or elements expressly listed or inherent to such process, method, article, or apparatus.
It should be noted that, without conflict, the embodiments of the present invention and features of the embodiments may be combined with each other. The invention will be described in detail below with reference to the drawings in connection with embodiments.
The invention provides a method for analyzing the influence of SVG on a doubly-fed grid-connected system based on complex circuit modal power, which is used for analyzing the influence of SVG on the stability and oscillation mode of the doubly-fed grid-connected system.
Fig. 1 is a flowchart of a method for analyzing an influence of SVG on a doubly-fed grid-connected system according to an embodiment of the present invention, as shown in fig. 1, the method for analyzing an influence of SVG on a doubly-fed grid-connected system according to the embodiment of the present invention includes steps S101 to S104.
Step S101, an equivalent model of interaction of SVG and a doubly-fed grid-connected system is obtained.
In the embodiment of the invention, the double-fed grid-connected system consists of double-fed equipment, a converter and an alternating current power grid, wherein the double-fed equipment can be double-fed pumping and accumulating equipment or a double-fed wind turbine generator set and the like, and the double-fed equipment is connected with the alternating current power grid through the converter to form the double-fed grid-connected system.
SVG (static var generator) can carry out reactive compensation to doubly-fed grid-connected system to can provide voltage support for the system, SVG has the characteristics that adjustable ability is strong, response speed is fast and reliability is high. The control strategy of the currently used SVG (static var generator) mainly adopts fixed reactive power control or fixed alternating voltage control.
In one embodiment of the invention, the equivalent model is constructed by the generalized impedance and equivalent primary-dual complex circuit analysis method in the small-interference stability analysis.
And S102, simplifying the equivalent model into a single-input single-output equivalent complex circuit model.
In one embodiment of the present invention, the step may specifically reduce the equivalent model to a single-input single-output equivalent complex circuit model by linear transformation.
In one embodiment of the invention, a single-input single-output equivalent complex circuit model (equivalent complex circuit) of the invention can be shown in fig. 5, the equivalent complex circuit can represent the stability of a converter and an SVG interactive system, the added parallel generalized impedance in the equivalent complex circuit of the system can be regarded as the additional impedance of the SVG to the original converter grid-connected system, and the equivalent complex circuit after the equivalent has stability equivalence with the original doubly-fed and SVG interactive system, namely, the resonance zero point of the single-input single-output equivalent complex circuit model is the characteristic root of the equivalent model.
In FIG. 5, Y PR_v ,Y DR_v The method comprises the steps of respectively obtaining a rotor-side converter source and dual generalized admittance of doubly-fed equipment; y is Y PG_v ,Y DG_v The method comprises the steps of respectively obtaining a source and dual generalized admittance of a network side converter of the doubly fed equipment; ΔY P_sys ,ΔY D_sys The additional source and dual admittances of the SVG to the system are respectively; y is Y P_net ,Y D_net The method comprises the steps of respectively obtaining an alternating current network source and dual generalized admittance; y is Y PRD_v The admittance of the doubly-fed device rotor-side converter between the node P and the node D; y is Y PGD_v The mutual admittance of the doubly-fed equipment network-side converter between the node P and the node D; ΔY PD_v Is the admittance of SVG between node P and node D; s represents the laplace operator; y is Y s11 ，Y s22 Is a polar impedance model expression of SVG; y is Y v1 ，Y v4 Is doubly fedThe polar coordinate impedance model expression of the equipment network side converter; y is Y g1 ，Y g4 The method is a doubly-fed equipment rotor side converter polar coordinate impedance model expression; c (C) f A filter capacitor matrix is arranged at the outlet of the converter; b is an admittance matrix of the nodes of the alternating current network system after node compression; omega 0 Angular frequency is synchronized for the grid.
Wherein:
and step S103, obtaining an influence factor index of SVG additional impedance on the doubly-fed grid-connected system oscillation mode according to the single-input single-output equivalent complex circuit model.
In one embodiment of the invention, the step can specifically obtain an influence factor index of SVG additional impedance on the oscillation mode of the doubly-fed grid-connected system by utilizing a complex circuit mode power analysis method aiming at the single-input single-output equivalent complex circuit model.
In one embodiment of the invention, mu is used for the index of the impact factor of SVG additional impedance on the oscillation mode of the doubly-fed grid-connected system s To represent.
In one embodiment of the invention, the influence of SVG on the stability and oscillation mode of the doubly-fed grid-connected system is evaluated by adopting the following formula:
wherein k is o Is a modal power coefficient, and the expression can beo k Is a modal power factor, the expression of which can be +.>Y P_k ，Y D_k Representing the primary and dual admittances of the doubly-fed device and the ac network, respectively, i.e. Y P_k ＝Y PR_v +Y PG_v +Y P_net ，Y D_k ＝Y DR_v +Y DG_v +Y D_net ；Y * P_k ，Y * D_k Representing the conjugation of the original and dual admittances of the doubly fed device and the ac grid, respectively; y is Y PD_v ,Y * PD_v Representing the mutual admittance and the conjugate component of the doubly fed device between node P and node D, respectively, wherein Y PD_v ＝Y PRD_v +Y PGD_v ；/>The voltage conjugation of the equivalent original-dual circuit of the doubly fed and SVG interactive system at the node P and the node D is respectively carried out; y is an admittance matrix of an equivalent original-dual complex circuit of the doubly fed and SVG interactive system, and the expression can be as follows:
wherein:
u is the voltage vector that satisfies yu=0, i.e., the right eigenvector of matrix Y.
In a specific embodiment of the present invention, the impact factor index is calculated according to the generalized admittance of the doubly-fed device and the ac power grid in the doubly-fed grid-connected system, and the additional admittance introduced after the doubly-fed grid-connected system joins the SVG.
And step S104, determining the influence of SVG on the doubly-fed grid-connected system according to the influence factor index.
In one embodiment of the present invention, the influence of the SVG on the doubly-fed grid-connected system is determined according to the influence factor index in step S104, specifically, the influence of the SVG on the stability and the oscillation frequency of the doubly-fed grid-connected system is determined according to the influence factor index.
FIG. 2 is a flow chart of determining the effect of SVG on the stability of a doubly-fed grid-tie system according to an embodiment of the invention, as shown in FIG. 2, in an alternative embodiment of the invention, the flow of determining the effect of SVG on the stability of a doubly-fed grid-tie system comprises steps S201 and S202.
Step S201, if the real part of the influence factor index is positive, determining that SVG is added to reduce the stability of the doubly-fed grid-connected system.
Step S202, if the real part of the influence factor index is negative, determining to add SVG to improve the stability of the doubly-fed grid-connected system.
FIG. 3 is a flowchart illustrating the determination of the effect of SVG on the oscillation frequency of a doubly-fed grid-tie system according to an embodiment of the present invention, as shown in FIG. 3, in an alternative embodiment of the present invention, the determination of the effect of SVG on the oscillation frequency of a doubly-fed grid-tie system includes steps S301 and S302.
Step S301, if the imaginary part of the influence factor index is positive, determining to add SVG to improve the oscillation frequency of the doubly-fed grid system.
And step S302, if the imaginary part of the influence factor index is negative, determining to add SVG to reduce the oscillation frequency of the doubly-fed grid system.
In an embodiment of the invention, μ s (s 1 ) Can be reflected in the oscillation mode s 1 The influence of SVG on the oscillation mode of the original system is defined as an influence factor index. Wherein Re (mu) s ) I.e. influencing factor index mu s Represents the effect of SVG on system stability if Re (μ) s ) Providing damping effect for the system by the SVG represented negatively, improving the stability of the system after adding, otherwise, deteriorating the small interference stability of the system by the SVG; im (mu) s ) I.e. influencing factor index mu s Is representative of the influence of SVG on the system oscillation frequency if Im(s) 1 ) Is positive and Im (mu) s ) The positive indication is that the oscillation frequency increases after SVG addition, whereas Im (μ) s ) The oscillation frequency is reduced for a negative system.
Therefore, the invention can convert the stability problem of SVG access to the doubly-fed grid-connected system into the stability problem of a single-input single-output (SISO) equivalent circuit, and elements which are difficult to analyze such as a phase shifter and the like are not existed in the SISO equivalent complex circuit of the system. The method has definite physical mechanism and accurate characterization on the small-interference stability of the system, and can be applied to analyze the influence of SVG on the oscillation mode of doubly-fed equipment and the influence of SVG control structure and parameters on the stability of the system.
The invention will be described in further detail with reference to the accompanying drawings and specific examples.
According to the equivalent original-dual circuit of the established doubly-fed and SVG interactive system, the invention selects the generalized admittance of doubly-fed equipment and an alternating current power grid and the additional admittance introduced after the doubly-fed grid-connected system is added with SVG to calculate the influence factor index mu s According to the index mu of the influencing factor s And evaluating the influence of SVG on the stability and oscillation frequency of the doubly-fed grid-connected system.
Specific embodiments of the invention are as follows:
the structure of the converter and SVG interactive system shown in fig. 6 is adopted, wherein the converter adopts a control mode of a constant direct current voltage outer ring, and a frequency domain model and a time domain model of the system are built in Matlab/Simulink to verify theoretical analysis. Because the double-fed equipment grid-connected system can generate two oscillation problems of a middle frequency band and a low frequency band, simulation needs to be carried out respectively, two groups of parameters shown in table 1 are adopted for discussion analysis respectively, and system and equipment control parameters are shown in table 1 and table 2. In FIG. 6, L f 、C f And L g Respectively a filter inductance, a filter capacitance and a line inductance, L m Is mutual inductance of the motor, C dc Is a direct current capacitor L T Is the inductance of the transformer, U dc Measuring voltage for the direct current of the inverter;
table 1 converter grid-tie system parameters
TABLE 2 grid-connected SVG control parameters
The method comprises the steps of establishing a system impedance model under the working condition, taking current flowing into doubly-fed equipment as positive, and a dynamic model of a network-side converter of the doubly-fed equipment is as follows:
wherein:
wherein the subscript 0 denotes the steady state value of each variable, G 3 (s)＝K dcp +K dci S is the transfer function of the PI controller of the dc voltage outer loop; g 4 (s)＝K cp +K ci And/s is the transfer function of the PI controller of the current inner loop.
The dynamic model of the rotor-side converter of the doubly-fed equipment unit is as follows:
wherein:
in the method, in the process of the invention,U 0 outputting the amplitude of the steady-state voltage for the motor; i s0 The amplitude of the steady-state current of the motor stator; i r0 The amplitude of the steady-state current of the motor rotor; />Is the steady-state phase of the motor stator current; g 1 (s)＝K sp +K si S is the transfer function of the PI controller of the power outer loop; g 2 (s)＝K rp +K ri S is the transfer function of the PI controller of the rotor-side current inner loop; l (L) m The motor is mutually induced; l (L) r ＝L σr +L m The rotor side inductance; l (L) s ＝L σs +L m Is the inductance of the stator side;
the polar impedance model of SVG is:
for the ac voltage outer loop control scheme, the impedance expression is:
for the reactive outer loop control mode, the impedance expression is:
wherein: l (L) f Is a filter inductance, omega is the output angular frequency of the phase-locked loop, theta pll For outputting the electric angle, H, of the phase-locked loop i (s) is an inner loop transfer function, G ac (s)、G q (s) is an outer loop transfer function, H pll (s) is a phase-locked loop transfer function, expressed as:
wherein:for each transfer function proportional parameter, < >>The parameters are integrated for each transfer function.
The equipment and the power grid outside the ports of the converter and the SVG are regarded as a network system, and the obtained system dynamic equation is as follows:
in the method, in the process of the invention,b is a system node admittance matrix after node compression, L is a filter capacitance matrix g Is the sum of the filtering inductance and the line inductance of the LC filter, L 1T ，L 2T For the inductance of the transformer, represents the Kronecker product. Wherein:
the mode power can represent the participation degree of each generalized admittance in the complex circuit to the oscillation mode, so that the generalized admittance causing the system oscillation can be obtained according to the mode power. After the SVG is added into the doubly-fed equipment grid-connected system, the additional admittance introduced into the complex circuit is delta Y P_sys ,ΔY D_sys ,ΔY PD_v As shown in FIG. 5, it is illustrated that SVG influences system modal power by adjusting network generalized impedance and generalized impedance of current transformer, thereby generating power for system stabilityThe influence is generated. In this oscillation mode, the additional admittance of the SVG is parallel to the generalized admittance of the system, marked with a dashed line. Therefore, the influence of the SVG on the system stability can be estimated according to the analysis expression of the SVG additional impedance on the system oscillation mode.
After the introduction of SVG, the stability of the grid-connected system of the doubly-fed device is changed as shown in Table 3. For the oscillation mode 1 of the medium-frequency double-fed equipment, the stability of the system is slightly reduced after the SVG is added. And for the oscillation mode 2 of the low frequency band, the stability of the system is improved after the SVG is added.
TABLE 3 influence of different oscillation modes of doubly fed device on SVG addition
Therefore, the method and the device can be applied to analysis and evaluation of the influence of SVG on the oscillation mode of the doubly-fed grid-connected equipment, and reduce the risk of oscillation of the doubly-fed grid-connected system caused by the introduction of SVG.
It should be noted that the steps illustrated in the flowcharts of the figures may be performed in a computer system such as a set of computer executable instructions, and that although a logical order is illustrated in the flowcharts, in some cases the steps illustrated or described may be performed in an order other than that illustrated herein.
Based on the same inventive concept, the embodiment of the present invention further provides a device for analyzing the influence of SVG on the doubly-fed grid-connected system, which may be used to implement the method for analyzing the influence of SVG on the doubly-fed grid-connected system described in the above embodiment, as described in the following embodiments. Since the principle of the device for analyzing the influence of SVG on the doubly-fed grid-connected system to solve the problem is similar to the method for analyzing the influence of SVG on the doubly-fed grid-connected system, the embodiment of the device for analyzing the influence of SVG on the doubly-fed grid-connected system can refer to the embodiment of the method for analyzing the influence of SVG on the doubly-fed grid-connected system, and the repetition is not repeated. As used below, the term "unit" or "module" may be a combination of software and/or hardware that implements the intended function. While the means described in the following embodiments are preferably implemented in software, implementation in hardware, or a combination of software and hardware, is also possible and contemplated.
FIG. 4 is a block diagram of an apparatus for analyzing an influence of SVG on a doubly-fed grid-connected system according to an embodiment of the present invention, as shown in FIG. 4, the apparatus for analyzing an influence of SVG on a doubly-fed grid-connected system according to an embodiment of the present invention includes:
the equivalent model acquisition unit 1 is used for acquiring an equivalent model of interaction of the SVG and the doubly-fed grid system;
a model transformation unit 2 for simplifying the equivalent model into a single-input single-output equivalent complex circuit model;
the influence factor index determining unit 3 is used for obtaining an influence factor index of the SVG additional impedance on the system oscillation mode according to the single-input single-output equivalent complex circuit model;
and the influence analysis unit 4 is used for determining the influence of the SVG on the doubly-fed grid-connected system according to the influence factor index.
In one embodiment of the invention, the model transforming unit 2 may reduce the equivalent model to a single-input single-output equivalent complex circuit model by linear transformation.
In one embodiment of the present invention, the impact factor index determining unit 3 may obtain, for the single-input single-output equivalent complex circuit model, an impact factor index of the SVG additional impedance on the system oscillation mode by using a complex circuit mode power analysis method.
In one embodiment of the present invention, the impact analysis unit 4 is specifically configured to determine the impact of the SVG on the stability and the oscillation frequency of the doubly-fed grid system according to the impact factor index.
In one embodiment of the invention, the impact analysis unit 4 comprises:
the first analysis module is used for determining that the stability of the doubly-fed grid-connected system is reduced by adding SVG if the real part of the influence factor index is positive;
and the second analysis module is used for determining that the SVG is added to improve the stability of the doubly-fed grid-connected system if the real part of the influence factor index is negative.
In one embodiment of the present invention, the impact analysis unit 4 further includes:
the third analysis module is used for determining that SVG is added to improve the oscillation frequency of the doubly-fed grid system if the imaginary part of the influence factor index is positive;
and the fourth analysis module is used for determining that SVG is added to reduce the oscillation frequency of the doubly-fed grid system if the imaginary part of the influence factor index is negative.
To achieve the above object, according to another aspect of the present application, there is also provided a computer apparatus. As shown in fig. 7, the computer device includes a memory, a processor, a communication interface, and a communication bus, on which a computer program executable on the processor is stored, which processor implements the steps of the method of the embodiments described above when executing the computer program.
The processor may be a central processing unit (Central Processing Unit, CPU). The processor may also be any other general purpose processor, digital signal processor (Digital Signal Processor, DSP), application specific integrated circuit (Application Specific Integrated Circuit, ASIC), field programmable gate array (Field-Programmable Gate Array, FPGA) or other programmable logic device, discrete gate or transistor logic, discrete hardware components, or any combination thereof.
The memory is used as a non-transitory computer readable storage medium for storing non-transitory software programs, non-transitory computer executable programs, and units, such as corresponding program units in the above-described method embodiments of the invention. The processor executes the various functional applications of the processor and the processing of the composition data by running non-transitory software programs, instructions and modules stored in the memory, i.e., implementing the methods of the method embodiments described above.
The memory may include a memory program area and a memory data area, wherein the memory program area may store an operating system, at least one application program required for a function; the storage data area may store data created by the processor, etc. In addition, the memory may include high-speed random access memory, and may also include non-transitory memory, such as at least one magnetic disk storage device, flash memory device, or other non-transitory solid state storage device. In some embodiments, the memory may optionally include memory located remotely from the processor, the remote memory being connectable to the processor through a network. Examples of such networks include, but are not limited to, the internet, intranets, local area networks, mobile communication networks, and combinations thereof.
The one or more units are stored in the memory, which when executed by the processor, performs the method in the above embodiments.
The details of the computer device may be correspondingly understood by referring to the corresponding relevant descriptions and effects in the above embodiments, and will not be repeated here.
To achieve the above object, according to another aspect of the present application, there is also provided a computer readable storage medium storing a computer program which, when executed in a computer processor, implements the steps in the method of analyzing the effect of SVG on a doubly-fed grid-connected system described above. It will be appreciated by those skilled in the art that implementing all or part of the above-described embodiment method may be implemented by a computer program to instruct related hardware, where the program may be stored in a computer readable storage medium, and the program may include the above-described embodiment method when executed. Wherein the storage medium may be a magnetic Disk, an optical Disk, a Read-Only Memory (ROM), a random access Memory (RandomAccessMemory, RAM), a Flash Memory (Flash Memory), a Hard Disk (HDD), a Solid State Drive (SSD), or the like; the storage medium may also comprise a combination of memories of the kind described above.
It will be apparent to those skilled in the art that the modules or steps of the invention described above may be implemented in a general purpose computing device, they may be concentrated on a single computing device, or distributed across a network of computing devices, or they may alternatively be implemented in program code executable by computing devices, such that they may be stored in a memory device for execution by the computing devices, or they may be separately fabricated into individual integrated circuit modules, or multiple modules or steps within them may be fabricated into a single integrated circuit module. Thus, the present invention is not limited to any specific combination of hardware and software.
The above description is only of the preferred embodiments of the present invention and is not intended to limit the present invention, but various modifications and variations can be made to the present invention by those skilled in the art. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention should be included in the protection scope of the present invention.
Claims (10)
1. A method of analyzing the effect of SVG on a doubly-fed grid-tie system, comprising:
obtaining an equivalent model of SVG and double-fed grid-connected system interaction, wherein the double-fed grid-connected system consists of double-fed equipment, a converter and an alternating current power grid, the double-fed equipment is connected with the alternating current power grid through the converter, and the equivalent model is constructed through a generalized impedance and an equivalent original-dual circuit analysis method in small-interference stability analysis;
the equivalent model is simplified into a single-input single-output equivalent complex circuit model, the equivalent complex circuit can represent the interaction stability of the converter and the SVG, the parallel generalized impedance in the equivalent complex circuit model can be regarded as the additional impedance of the SVG to the doubly-fed grid-connected system, and the equivalent complex circuit model has stability equivalence with the doubly-fed grid-connected system and the SVG interaction system after the equivalent complex circuit model, namely the resonance zero point of the single-input single-output equivalent complex circuit model is the characteristic root of the equivalent model;
obtaining an influence factor index of SVG additional impedance to the oscillation mode of the doubly-fed grid-connected system according to the single-input single-output equivalent complex circuit model, wherein the influence factor index is calculated according to the generalized admittance of doubly-fed equipment and an alternating-current power grid in the doubly-fed grid-connected system and the additional admittance introduced after the doubly-fed grid-connected system is added with SVG;
and determining the influence of the SVG on the doubly-fed grid-connected system according to the influence factor index.
2. The method of analyzing the effect of SVG on a doubly-fed grid-tie system according to claim 1, wherein said determining the effect of SVG on a doubly-fed grid-tie system based on said impact factor indicator comprises:
and determining the influence of the SVG on the stability and the oscillation frequency of the doubly-fed grid-connected system according to the influence factor index.
3. The method of analyzing the effect of SVG on a doubly-fed grid-tie system according to claim 2, wherein said determining the effect of SVG on the stability and oscillation frequency of the doubly-fed grid-tie system based on said impact factor indicator comprises:
if the real part of the influence factor index is positive, determining that SVG is added to reduce the stability of the doubly-fed grid-connected system;
and if the real part of the influence factor index is negative, determining to add SVG to improve the stability of the doubly-fed grid-connected system.
4. The method of analyzing the effect of SVG on a doubly-fed grid-tie system according to claim 2, wherein said determining the effect of SVG on the stability and oscillation frequency of the doubly-fed grid-tie system based on said impact factor indicator comprises:
if the imaginary part of the influence factor index is positive, determining to add SVG to improve the oscillation frequency of the doubly-fed grid-connected system;
and if the imaginary part of the influence factor index is negative, determining to add SVG to reduce the oscillation frequency of the doubly-fed grid-connected system.
5. An apparatus for analyzing the effect of SVG on a doubly-fed grid-tie system, comprising:
the system comprises an equivalent model acquisition unit, a simulation unit and a simulation unit, wherein the equivalent model acquisition unit is used for acquiring an equivalent model of interaction between SVG and a doubly-fed grid-connected system, the doubly-fed grid-connected system consists of doubly-fed equipment, a converter and an alternating-current power grid, the doubly-fed equipment is connected with the alternating-current power grid through the converter, and the equivalent model is constructed through a generalized impedance and an equivalent original-dual circuit analysis method in small-interference stability analysis;
the model transformation unit is used for simplifying the equivalent model into a single-input single-output equivalent complex circuit model, the equivalent complex circuit can represent the interaction stability of the converter and the SVG, the parallel generalized impedance in the equivalent complex circuit model can be regarded as the additional impedance of the SVG to the doubly-fed grid-connected system, and the equivalent complex circuit model has stability equivalence with the doubly-fed grid-connected system and the SVG interaction system after the equivalent complex circuit model, namely the resonance zero point of the single-input single-output equivalent complex circuit model is the characteristic root of the equivalent model;
the influence factor index determining unit is used for obtaining an influence factor index of SVG additional impedance on a system oscillation mode according to the single-input single-output equivalent complex circuit model, wherein the influence factor index is calculated according to generalized admittance of double-fed equipment and an alternating current power grid in a double-fed grid-connected system and additional admittance introduced after the double-fed grid-connected system is added with SVG;
and the influence analysis unit is used for determining the influence of the SVG on the doubly-fed grid system according to the influence factor index.
6. The apparatus for analyzing the influence of SVG on a doubly-fed grid-connected system according to claim 5, wherein said influence analyzing unit is specifically configured to determine the influence of SVG on the stability and the oscillation frequency of the doubly-fed grid-connected system according to said influence factor index.
7. The apparatus for analyzing an effect of SVG on a doubly-fed grid-tie system according to claim 6, wherein said effect analysis unit comprises:
the first analysis module is used for determining that the stability of the doubly-fed grid-connected system is reduced by adding SVG if the real part of the influence factor index is positive;
and the second analysis module is used for determining that the SVG is added to improve the stability of the doubly-fed grid-connected system if the real part of the influence factor index is negative.
8. The apparatus for analyzing an effect of SVG on a doubly-fed grid-tie system according to claim 6, wherein said effect analysis unit comprises:
the third analysis module is used for determining that SVG is added to improve the oscillation frequency of the doubly-fed grid system if the imaginary part of the influence factor index is positive;
and the fourth analysis module is used for determining that SVG is added to reduce the oscillation frequency of the doubly-fed grid system if the imaginary part of the influence factor index is negative.
9. A computer device comprising a memory, a processor and a computer program stored on the memory and executable on the processor, characterized in that the processor implements the method of any of claims 1 to 4 when executing the computer program.
10. A computer readable storage medium storing a computer program, characterized in that the computer program when executed in a computer processor implements the method of any one of claims 1 to 4.
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Citations (14)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN104268795A (en) * | 2014-09-22 | 2015-01-07 | 珠海许继芝电网自动化有限公司 | Power distribution network stock graph-module data interaction optimization method |
| CN104951996A (en) * | 2015-05-21 | 2015-09-30 | 北京科东电力控制系统有限责任公司 | Power distribution network operation monitoring method based on scalable vector graphics |
| WO2016054856A1 (en) * | 2014-09-19 | 2016-04-14 | 成都麦隆电气有限公司 | Energy double-fed device with pfc and grid compensation functions |
| CN105550247A (en) * | 2015-12-08 | 2016-05-04 | 许继电气股份有限公司 | SVG standard customizable graphic symbol based power system graphic display method |
| CN106849161A (en) * | 2017-02-09 | 2017-06-13 | 国网冀北电力有限公司张家口供电公司 | Analysis method and device that straight drive blower influences on transmission system subsynchronous resonance |
| KR20180041307A (en) * | 2016-10-14 | 2018-04-24 | 이엔유 주식회사 | Template application system and method using the file format svg |
| CN109449958A (en) * | 2018-11-29 | 2019-03-08 | 云南电网有限责任公司 | A kind of double-fed blower grid-connected system method for analyzing stability |
| CN109449955A (en) * | 2018-10-24 | 2019-03-08 | 中国电力科学研究院有限公司 | A kind of double-fed blower and static reactive generator control method, controller and device |
| CN109709429A (en) * | 2019-01-10 | 2019-05-03 | 华北电力科学研究院有限责任公司 | Wind power system ferromagnetic resonance analysis method and device |
| CN111095258A (en) * | 2017-06-29 | 2020-05-01 | 最佳应用有限责任公司 | Computer-assisted system and method for creating customized products |
| CN111399381A (en) * | 2020-03-30 | 2020-07-10 | 南京航空航天大学 | Method and system for shaping output impedance of converter |
| AU2020101819A4 (en) * | 2020-08-14 | 2020-09-24 | Xuchang University | A kind of fault handling system and unit structure of doubly-fed wind turbine generator |
| CN112149280A (en) * | 2020-08-25 | 2020-12-29 | 浙江大学 | Method for obtaining power grid strength of multi-feed-in system of new energy containing SVG |
| EP3951635A1 (en) * | 2020-08-07 | 2022-02-09 | Beijing Xiaomi Mobile Software Co., Ltd. | Method and apparatus for determining charging circuit, electronic device, and storage medium |
Family Cites Families (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US11404973B2 (en) * | 2018-12-19 | 2022-08-02 | Di Shi | Generalized equivalent circuit model of MMC-HVDC for power system simulation |
| US11714934B2 (en) * | 2019-06-18 | 2023-08-01 | The Governors Of The University Of Alberta | Aggregated model of large-scale wind farms for power system simulation software tools |
-
2021
- 2021-01-26 CN CN202110103167.0A patent/CN112765932B/en active Active
Patent Citations (14)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2016054856A1 (en) * | 2014-09-19 | 2016-04-14 | 成都麦隆电气有限公司 | Energy double-fed device with pfc and grid compensation functions |
| CN104268795A (en) * | 2014-09-22 | 2015-01-07 | 珠海许继芝电网自动化有限公司 | Power distribution network stock graph-module data interaction optimization method |
| CN104951996A (en) * | 2015-05-21 | 2015-09-30 | 北京科东电力控制系统有限责任公司 | Power distribution network operation monitoring method based on scalable vector graphics |
| CN105550247A (en) * | 2015-12-08 | 2016-05-04 | 许继电气股份有限公司 | SVG standard customizable graphic symbol based power system graphic display method |
| KR20180041307A (en) * | 2016-10-14 | 2018-04-24 | 이엔유 주식회사 | Template application system and method using the file format svg |
| CN106849161A (en) * | 2017-02-09 | 2017-06-13 | 国网冀北电力有限公司张家口供电公司 | Analysis method and device that straight drive blower influences on transmission system subsynchronous resonance |
| CN111095258A (en) * | 2017-06-29 | 2020-05-01 | 最佳应用有限责任公司 | Computer-assisted system and method for creating customized products |
| CN109449955A (en) * | 2018-10-24 | 2019-03-08 | 中国电力科学研究院有限公司 | A kind of double-fed blower and static reactive generator control method, controller and device |
| CN109449958A (en) * | 2018-11-29 | 2019-03-08 | 云南电网有限责任公司 | A kind of double-fed blower grid-connected system method for analyzing stability |
| CN109709429A (en) * | 2019-01-10 | 2019-05-03 | 华北电力科学研究院有限责任公司 | Wind power system ferromagnetic resonance analysis method and device |
| CN111399381A (en) * | 2020-03-30 | 2020-07-10 | 南京航空航天大学 | Method and system for shaping output impedance of converter |
| EP3951635A1 (en) * | 2020-08-07 | 2022-02-09 | Beijing Xiaomi Mobile Software Co., Ltd. | Method and apparatus for determining charging circuit, electronic device, and storage medium |
| AU2020101819A4 (en) * | 2020-08-14 | 2020-09-24 | Xuchang University | A kind of fault handling system and unit structure of doubly-fed wind turbine generator |
| CN112149280A (en) * | 2020-08-25 | 2020-12-29 | 浙江大学 | Method for obtaining power grid strength of multi-feed-in system of new energy containing SVG |
Non-Patent Citations (1)
| Title |
|---|
| SVG对风电次同步振荡影响的研究;谢欢等;华北电力技术;37-41 * |
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