CN116316674A - Power control stability judging method and device for new energy station grid-connected system - Google Patents
Power control stability judging method and device for new energy station grid-connected system Download PDFInfo
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- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02J—CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
- H02J3/00—Circuit arrangements for ac mains or ac distribution networks
- H02J3/24—Arrangements for preventing or reducing oscillations of power in networks
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- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02J—CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
- H02J3/00—Circuit arrangements for ac mains or ac distribution networks
- H02J3/38—Arrangements for parallely feeding a single network by two or more generators, converters or transformers
- H02J3/46—Controlling of the sharing of output between the generators, converters, or transformers
- H02J3/48—Controlling the sharing of the in-phase component
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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
- H02J3/38—Arrangements for parallely feeding a single network by two or more generators, converters or transformers
- H02J3/46—Controlling of the sharing of output between the generators, converters, or transformers
- H02J3/50—Controlling the sharing of the out-of-phase component
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Abstract
The invention discloses a method and a device for judging power control stability of a new energy station grid-connected system. The method comprises the following steps: establishing a Thevenin equivalent circuit according to the electrical quantity information of the new energy station grid-connected system acquired through a typical structure diagram of the new energy station grid-connected system; based on a power system tide equation and a KVL equation, determining a grid-connected point voltage formula, an active power output expression and a reactive power output expression of a new energy station grid-connected system according to a Thevenin equivalent circuit; decomposing the grid-connected point output current of the new energy station grid-connected system under a VSC rotation coordinate system to obtain d-axis current components and q-axis current components of the grid-connected point output current, bringing the d-axis current components and the q-axis current components into the expression, and determining active control stability criteria and reactive control stability criteria of the new energy station grid-connected system; and determining the power control stability of the grid-connected system of the new energy station according to the active control stability criterion and the reactive control stability criterion.
Description
Technical Field
The invention relates to the technical field of new energy grid-connected systems, in particular to a method and a device for judging power control stability of a new energy station grid-connected system.
Background
With the continuous promotion of the construction of novel power systems, the large-scale new energy grid-connected trend is obvious, a large number of power electronic devices are widely applied, and the operation characteristics of the power systems are greatly changed. The stability of the new energy grid-connected system is timely judged, a beneficial reference can be provided for planning a novel power system taking new energy as a main body, and the method has important significance for guaranteeing safe and stable operation of the system and solving the problem of limited delivery capacity of a new energy weak current grid.
The new energy unit takes a voltage source type inverter (voltage source converter, VSC) as a grid-connected interface, and a control system of the new energy unit mainly comprises a power outer ring, a current inner ring and a phase-locked loop. The VSC outer loop control structure is essentially a control of the d-q axis current reference value, since the VSC inner loop control speed is much greater than the outer loop, it can reasonably be assumed that the inner loop current output value remains consistent with the current reference value at the moment. Meanwhile, when the system is in a steady state, the phase locked loop can be considered to operate in an ideal state. Therefore, under the condition of strong power grid supporting capability, the voltage of the grid-connected point is approximately constant, the active and reactive outputs of the new energy station are respectively proportional to the d-axis current and the q-axis current under the rotating coordinate system, and the aim of active and reactive decoupling control can be achieved. However, when the power grid supporting capability is weaker, the power output by the new energy station is affected by the grid-connected point voltage, the coupling of the active power, the q-axis current, the reactive power and the d-axis current is deepened, the original control target is deviated, the outer loop control coordination is damaged, and finally the new energy grid-connected system is unstable.
Disclosure of Invention
Aiming at the defects of the prior art, the invention provides a method and a device for judging the power control stability of a new energy station grid-connected system.
According to one aspect of the invention, a method for judging power control stability of a new energy station grid-connected system is provided, comprising the following steps:
acquiring electrical quantity information of the new energy station grid-connected system through a typical structure diagram of the new energy station grid-connected system, and establishing a Thevenin equivalent circuit according to the electrical quantity information;
based on a power system tide equation and a KVL equation, determining a grid-connected point voltage formula, an active power output expression and a reactive power output expression of a new energy station grid-connected system according to a Thevenin equivalent circuit;
decomposing the grid-connected point output current of the new energy station grid-connected system under a VSC rotation coordinate system to obtain a d-axis current component and a q-axis current component of the grid-connected point output current;
bringing the d-axis current component and the q-axis current component into a grid-connected point voltage formula, an active power output expression and a reactive power output expression, and determining an active control stability criterion and a reactive control stability criterion of a new energy station grid-connected system;
and determining the power control stability of the grid-connected system of the new energy station according to the active control stability criterion and the reactive control stability criterion.
Optionally, the operations of bringing the d-axis current component and the q-axis current component into the grid-connected point voltage formula, the active power output expression and the reactive power output expression to determine an active control stability criterion and a reactive control stability criterion of the new energy station grid-connected system include:
bringing the d-axis current component and the q-axis current component into a grid-connected point voltage formula, an active power output expression and a reactive power output expression, and determining an active power relation and a reactive power relation of active power and reactive power and the d-axis current component and the q-axis current component;
and determining an active control stability criterion and a reactive control stability criterion of the grid-connected system of the new energy station according to the active power relation and the reactive power relation.
Optionally, the operation of constructing the active control stability criterion and the reactive control stability criterion of the grid-connected system of the new energy station according to the active power relation and the reactive power relation comprises the following steps:
linearizing an active power relation and a reactive power relation by taking a d-axis current component and a q-axis current component as independent variables, and determining an active power equation and a reactive power equation of an active power and reactive power and d-axis current component small signals and q-axis current component small signals;
and extracting coefficients of d-axis current component small signals and q-axis current component small signals in the active power equation and the reactive power equation, and determining an active control stability criterion and a reactive control stability criterion.
Optionally, determining the operation of the stability of the grid-connected system of the new energy station according to the active control stability criterion and the reactive control stability criterion includes:
when R is P And R is Q When the power control stability of the new energy station grid-connected system is greater than a first threshold value, the risk exists;
when R is P And R is Q When the power control of the new energy station grid-connected system is smaller than the first threshold value and larger than the second threshold value, the power control of the new energy station grid-connected system is at an unstable risk;
when R is P And R is Q When the power control of the new energy station grid-connected system is smaller than a second threshold value, the power control of the new energy station grid-connected system is kept stable, wherein R P For active control stabilization criteria, R Q Is a reactive control stability criterion.
According to another aspect of the present invention, there is provided a power control stability discriminating apparatus of a new energy station grid-connected system, including:
the building module is used for obtaining the electrical quantity information of the new energy station grid-connected system through a typical structure diagram of the new energy station grid-connected system and building a Thevenin equivalent circuit according to the electrical quantity information;
the first determining module is used for determining a grid-connected point voltage formula, an active power output expression and a reactive power output expression of the grid-connected system of the new energy station according to the Thevenin equivalent circuit based on a power flow equation and a KVL equation of the power system;
the decomposition module is used for decomposing the grid-connected point output current of the new energy station grid-connected system under the VSC rotation coordinate system to obtain a d-axis current component and a q-axis current component of the grid-connected point output current;
the second determining module is used for bringing the d-axis current component and the q-axis current component into a grid-connected point voltage formula, an active power output expression and a reactive power output expression to determine an active control stability criterion and a reactive control stability criterion of the new energy station grid-connected system;
and the third determining module is used for determining the power control stability of the grid-connected system of the new energy station according to the active control stability criterion and the reactive control stability criterion.
According to a further aspect of the present invention there is provided a computer readable storage medium storing a computer program for performing the method according to any one of the above aspects of the present invention.
According to still another aspect of the present invention, there is provided an electronic device including: a processor; a memory for storing the processor-executable instructions; the processor is configured to read the executable instructions from the memory and execute the instructions to implement the method according to any of the above aspects of the present invention.
Therefore, the mathematical relationship between key electric quantities is deduced on the basis of the Thevenin equivalent circuit of the new energy station grid-connected system, sensitivity analysis is carried out on output power and d-q axis current, and a new method for judging the power control stability of the new energy station grid-connected system is provided by comparing the relative magnitudes of the sensitivity. Aiming at the problem of aggravation of active and reactive output coupling degree under a weak current network, whether the control system can realize the original control target is judged by calculating the sensitivity of the output power and the d-q axis current. The method is used for judging the power control stability of the new energy grid-connected system.
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Exemplary embodiments of the present invention may be more completely understood in consideration of the following drawings:
fig. 1 is a flow chart of a method for judging power control stability of a new energy station grid-connected system according to an exemplary embodiment of the present invention;
fig. 2 is another flow chart of a power control stability determining method of a new energy station grid-connected system according to an exemplary embodiment of the present invention;
FIG. 3 is a schematic diagram of a new energy grid-connected system according to an exemplary embodiment of the present invention;
FIG. 4 is a schematic diagram of a Thevenin equivalent circuit of a new energy grid-connected system according to an exemplary embodiment of the present invention;
FIG. 5 is a diagram of R provided by an exemplary embodiment of the present invention P 、R Q Schematic diagrams of amplitude curves at different operating points;
fig. 6 is a schematic structural diagram of a power control stability determining device of a new energy station grid-connected system according to an exemplary embodiment of the present invention;
fig. 7 is a structure of an electronic device provided in an exemplary embodiment of the present invention.
Detailed Description
Hereinafter, exemplary embodiments according to the present invention will be described in detail with reference to the accompanying drawings. It should be apparent that the described embodiments are only some embodiments of the present invention and not all embodiments of the present invention, and it should be understood that the present invention is not limited by the example embodiments described herein.
It should be noted that: the relative arrangement of the components and steps, numerical expressions and numerical values set forth in these embodiments do not limit the scope of the present invention unless it is specifically stated otherwise.
It will be appreciated by those of skill in the art that the terms "first," "second," etc. in embodiments of the present invention are used merely to distinguish between different steps, devices or modules, etc., and do not represent any particular technical meaning nor necessarily logical order between them.
It should also be understood that in embodiments of the present invention, "plurality" may refer to two or more, and "at least one" may refer to one, two or more.
It should also be appreciated that any component, data, or structure referred to in an embodiment of the invention may be generally understood as one or more without explicit limitation or the contrary in the context.
In addition, the term "and/or" in the present invention is merely an association relationship describing the association object, and indicates that three relationships may exist, for example, a and/or B may indicate: a exists alone, A and B exist together, and B exists alone. In the present invention, the character "/" generally indicates that the front and rear related objects are an or relationship.
It should also be understood that the description of the embodiments of the present invention emphasizes the differences between the embodiments, and that the same or similar features may be referred to each other, and for brevity, will not be described in detail.
Meanwhile, it should be understood that the sizes of the respective parts shown in the drawings are not drawn in actual scale for convenience of description.
The following description of at least one exemplary embodiment is merely exemplary in nature and is in no way intended to limit the invention, its application, or uses.
Techniques, methods, and apparatus known to one of ordinary skill in the relevant art may not be discussed in detail, but where appropriate, the techniques, methods, and apparatus should be considered part of the specification.
It should be noted that: like reference numerals and letters denote like items in the following figures, and thus once an item is defined in one figure, no further discussion thereof is necessary in subsequent figures.
Embodiments of the invention are operational with numerous other general purpose or special purpose computing system environments or configurations with electronic devices, such as terminal devices, computer systems, servers, etc. Examples of well known terminal devices, computing systems, environments, and/or configurations that may be suitable for use with the terminal device, computer system, server, or other electronic device include, but are not limited to: personal computer systems, server computer systems, thin clients, thick clients, hand-held or laptop devices, microprocessor-based systems, set-top boxes, programmable consumer electronics, network personal computers, small computer systems, mainframe computer systems, and distributed cloud computing technology environments that include any of the foregoing, and the like.
Electronic devices such as terminal devices, computer systems, servers, etc. may be described in the general context of computer system-executable instructions, such as program modules, being executed by a computer system. Generally, program modules may include routines, programs, objects, components, logic, data structures, etc., that perform particular tasks or implement particular abstract data types. The computer system/server may be implemented in a distributed cloud computing environment in which tasks are performed by remote processing devices that are linked through a communications network. In a distributed cloud computing environment, program modules may be located in both local and remote computing system storage media including memory storage devices.
Exemplary method
Fig. 1 is a flow chart of a method for determining power control stability of a new energy station grid-connected system according to an exemplary embodiment of the present invention. The embodiment can be applied to an electronic device, as shown in fig. 1, the method 100 for judging the power control stability of a new energy station grid-connected system includes the following steps:
and 105, determining the power control stability of the grid-connected system of the new energy station according to the active control stability criterion and the reactive control stability criterion.
Optionally, the operations of bringing the d-axis current component and the q-axis current component into the grid-connected point voltage formula, the active power output expression and the reactive power output expression to determine an active control stability criterion and a reactive control stability criterion of the new energy station grid-connected system include:
bringing the d-axis current component and the q-axis current component into a grid-connected point voltage formula, an active power output expression and a reactive power output expression, and determining an active power relation and a reactive power relation of active power and reactive power and the d-axis current component and the q-axis current component;
and determining an active control stability criterion and a reactive control stability criterion of the grid-connected system of the new energy station according to the active power relation and the reactive power relation.
Optionally, the operation of constructing the active control stability criterion and the reactive control stability criterion of the grid-connected system of the new energy station according to the active power relation and the reactive power relation comprises the following steps:
linearizing an active power relation and a reactive power relation by taking a d-axis current component and a q-axis current component as independent variables, and determining an active power equation and a reactive power equation of an active power and reactive power and d-axis current component small signals and q-axis current component small signals;
and extracting coefficients of d-axis current component small signals and q-axis current component small signals in the active power equation and the reactive power equation, and determining an active control stability criterion and a reactive control stability criterion.
Optionally, determining the operation of the stability of the grid-connected system of the new energy station according to the active control stability criterion and the reactive control stability criterion includes:
when R is P And R is Q When the power control stability of the new energy station grid-connected system is greater than a first threshold value, the risk exists;
when R is P And R is Q When the energy is smaller than the first threshold value and larger than the second threshold value, new energy is generatedThe power control of the source station grid-connected system has unstable risk;
when R is P And R is Q When the power control of the new energy station grid-connected system is smaller than a second threshold value, the power control of the new energy station grid-connected system is kept stable, wherein R P For active control stabilization criteria, R Q Is a reactive control stability criterion.
Specifically, as shown in fig. 1 and 2, the method includes the steps of:
A. the relevant electric quantity is obtained by analyzing a new energy grid-connected typical structure diagram in the figure 3, and a Thevenin equivalent circuit is built, as shown in the figure 4;
B. based on the figure 4, neglecting the line resistance, calculating the grid-connected point voltage, the active power and the reactive power output expression;
C. assuming that the VSC phase-locked loop accurately tracks grid-connected point voltage, substituting output current into an expression formula in B in a d-q component form under a VSC rotation coordinate system;
D. the sensitivity analysis is carried out on d-axis current and q-axis current respectively by the expression type C, and a power control stability discrimination index R is established P And R is Q . When R is P And R is Q If the voltage is greater than the first threshold (the first threshold may be, but is not limited to, 10), the VSC primary control target is considered to deviate, active reactive independent control cannot be realized, and the stability of the grid-connected system of the new energy station is at risk.
In step a, a new energy grid-connected structure diagram in fig. 1 is analyzed to obtain related electric quantity, and a Thevenin equivalent circuit is built, as shown in fig. 4, and mainly includes: monitoring the voltage amplitude of the grid-connected point and the alternating current grid, the phase output by the phase-locked loop, and the active power and reactive power output by the grid-connected point;
in step B, based on fig. 4, the line resistance is ignored, and the grid-connected point voltage, active power and reactive power output expressions are calculated, which mainly include:
(1) When the new energy station grid-connected system is in a stable running state, based on a power system tide equation and a KVL equation, the grid-connected point voltage and power output expression are shown in formulas (1) - (3):
in U t 、U s The grid-connected point voltage and the alternating current grid voltage are respectively; i s Outputting current for the grid-connected point; θ is the phase of the phase-locked loop output; x is X s Reactance is the transmission line; p, Q are the output active power and reactive power, respectively.
In the step C, the VSC phase-locked loop is assumed to accurately track the voltage of the grid-connected point, the output current is expressed in a d-q component form under a VSC rotation coordinate system, and the output current is substituted into the expression in the B, and the method mainly comprises the following steps:
(1) Decomposing grid-connected point output current under a VSC rotation coordinate system to obtain the numerical value of the current under an alternating-direct axis, wherein the corresponding expression is shown as formula (4):
wherein i is sd 、i sq And d-axis component and q-axis component of the grid-connected point output current respectively.
(2) Substituting equation (4) into equation (1) yields the relationship between voltage Ut and isd, isq:
U t ∠θ＝U s +jX s (i sd +ji sq )e jθ (5)
(3) Substituting the current and voltage expressions of the formulas (4) and (5) into the active and reactive expressions of the formulas (2) and (3) can obtain the relational expression between the active, reactive and dq axis currents:
in the step D, the sensitivity analysis is carried out on D-axis current and q-axis current respectively by the expression in the C, and a power control stability discrimination index R is established P And R is Q . When R is P And R is Q If the voltage is more than 10, the VSC original control target deviates, the active reactive independent control cannot be realized, and the stability of the grid-connected system of the new energy station is at risk, and the method mainly comprises the following steps:
(1) In the formulas (6) and (7), P, Q is represented by i sd 、i sq Obtaining corresponding partial derivatives for independent variables to obtain
Wherein:
(2) Based on (8) and (9), a new energy station active control stability criterion R can be constructed P And reactive control stability criterion R Q ：
(3) When R is P And R is Q When the current value is more than 10, the deviation of the original control target of the grid-connected converter of the new energy station can be considered, and the current value can not be realizedActive and reactive independent control is carried out, and the power control stability of the grid-connected system of the new energy station is at risk; when R is P And R is Q When the power output of the grid-connected converter of the new energy station is smaller than 10 and larger than 0.1 (namely, the second threshold value can be but is not limited to 0.1), the power output of the grid-connected converter of the new energy station can be considered to be influenced by d-q axis current at the same time, and the unstable risk exists in the system power control; when RP and RQ are smaller than 0.1, the power output of the grid-connected converter of the new energy station is considered to be dominated by the original control target, and the power control is kept stable. As shown in FIG. 5, R is P 、R Q Amplitude curves at different operating points.
Therefore, the mathematical relationship between key electric quantities is deduced on the basis of the Thevenin equivalent circuit of the new energy station grid-connected system, sensitivity analysis is carried out on output power and d-q axis current, and a new method for judging the power control stability of the new energy station grid-connected system is provided by comparing the relative magnitudes of the sensitivity. Aiming at the problem of aggravation of active and reactive output coupling degree under a weak current network, whether the control system can realize the original control target is judged by calculating the sensitivity of the output power and the d-q axis current. The method is used for judging the power control stability of the new energy grid-connected system.
Exemplary apparatus
Fig. 6 is a schematic structural diagram of a power control stability determining device of a new energy station grid-connected system according to an exemplary embodiment of the present invention. As shown in fig. 6, the apparatus 600 includes:
the establishing module 610 is configured to obtain electrical quantity information of the new energy station grid-connected system through a typical structure diagram of the new energy station grid-connected system, and establish a Thevenin equivalent circuit according to the electrical quantity information;
the first determining module 620 is configured to determine a grid-connected point voltage formula, an active power output expression and a reactive power output expression of the new energy station grid-connected system according to the davin equivalent circuit based on a power system trend equation and a KVL equation;
the decomposition module 630 is configured to decompose the grid-connected point output current of the new energy station grid-connected system under the VSC rotation coordinate system to obtain a d-axis current component and a q-axis current component of the grid-connected point output current;
the second determining module 640 is configured to bring the d-axis current component and the q-axis current component into a grid-connected point voltage formula, an active power output expression and a reactive power output expression, and determine an active control stability criterion and a reactive control stability criterion of the new energy station grid-connected system;
and a third determining module 650, configured to determine the power control stability of the grid-connected system of the new energy station according to the active control stability criterion and the reactive control stability criterion.
Optionally, the second determining module 640 includes:
the first determining submodule is used for bringing the d-axis current component and the q-axis current component into a grid-connected point voltage formula, an active power output expression and a reactive power output expression, and determining an active power relation and a reactive power relation of the active power and the reactive power and the d-axis current component and the q-axis current component;
and the second determining submodule is used for determining an active control stability criterion and a reactive control stability criterion of the grid-connected system of the new energy station according to the active power relation and the reactive power relation.
Optionally, the second determining sub-module comprises:
the first determining unit is used for linearizing an active power relation and a reactive power relation by taking the d-axis current component and the q-axis current component as independent variables, and determining an active power equation and a reactive power equation of the active power and the reactive power and the d-axis current component small signals and the q-axis current component small signals;
and the second determining unit is used for extracting the coefficients of the d-axis current component small signal and the q-axis current component small signal in the active power equation and the reactive power equation and determining an active control stability criterion and a reactive control stability criterion.
Optionally, the third determining module 650 includes:
a first determination sub-module for determining when R P And R is Q When the new energy station grid-connected system is larger than the first threshold valueThe power control stability is at risk;
a second determination sub-module for determining when R P And R is Q When the power control of the new energy station grid-connected system is smaller than the first threshold value and larger than the second threshold value, the power control of the new energy station grid-connected system is at an unstable risk;
a third determination sub-module for determining when R P And R is Q When the power control of the new energy station grid-connected system is smaller than a second threshold value, the power control of the new energy station grid-connected system is kept stable, wherein R P For active control stabilization criteria, R Q Is a reactive control stability criterion.
Exemplary electronic device
Fig. 7 is a structure of an electronic device provided in an exemplary embodiment of the present invention. As shown in fig. 7, the electronic device 70 includes one or more processors 71 and memory 72.
The processor 71 may be a Central Processing Unit (CPU) or other form of processing unit having data processing and/or instruction execution capabilities, and may control other components in the electronic device to perform desired functions.
In addition, the input device 73 may also include, for example, a keyboard, a mouse, and the like.
The output device 74 can output various information to the outside. The output device 74 may include, for example, a display, speakers, a printer, and a communication network and remote output devices connected thereto, among others.
Of course, only some of the components of the electronic device relevant to the present invention are shown in fig. 7 for simplicity, components such as buses, input/output interfaces, etc. being omitted. In addition, the electronic device may include any other suitable components depending on the particular application.
Exemplary computer program product and computer readable storage Medium
In addition to the methods and apparatus described above, embodiments of the invention may also be a computer program product comprising computer program instructions which, when executed by a processor, cause the processor to perform steps in a method according to various embodiments of the invention described in the "exemplary methods" section of this specification.
The computer program product may write program code for performing operations of embodiments of the present invention in any combination of one or more programming languages, including an object oriented programming language such as Java, C++ or the like and conventional procedural programming languages, such as the "C" programming language or similar programming languages. The program code may execute entirely on the user's computing device, partly on the user's device, as a stand-alone software package, partly on the user's computing device, partly on a remote computing device, or entirely on the remote computing device or server.
Furthermore, embodiments of the present invention may also be a computer-readable storage medium, having stored thereon computer program instructions which, when executed by a processor, cause the processor to perform the steps in a method of mining history change records according to various embodiments of the present invention described in the "exemplary methods" section above in this specification.
The computer readable storage medium may employ any combination of one or more readable media. The readable medium may be a readable signal medium or a readable storage medium. The readable storage medium can include, for example, but is not limited to, an electronic, magnetic, optical, electromagnetic, infrared, or semiconductor system, or device, or a combination of any of the foregoing. More specific examples (a non-exhaustive list) of the readable storage medium would include the following: an electrical connection having one or more wires, a portable disk, a hard disk, random Access Memory (RAM), read-only memory (ROM), erasable programmable read-only memory (EPROM or flash memory), optical fiber, portable compact disk read-only memory (CD-ROM), an optical storage device, a magnetic storage device, or any suitable combination of the foregoing.
The basic principles of the present invention have been described above in connection with specific embodiments, however, it should be noted that the advantages, benefits, effects, etc. mentioned in the present invention are merely examples and not intended to be limiting, and these advantages, benefits, effects, etc. are not to be considered as essential to the various embodiments of the present invention. Furthermore, the specific details disclosed herein are for purposes of illustration and understanding only, and are not intended to be limiting, as the invention is not necessarily limited to practice with the above described specific details.
In this specification, each embodiment is described in a progressive manner, and each embodiment is mainly described in a different manner from other embodiments, so that the same or similar parts between the embodiments are mutually referred to. For system embodiments, the description is relatively simple as it essentially corresponds to method embodiments, and reference should be made to the description of method embodiments for relevant points.
The block diagrams of the devices, systems, apparatuses, systems according to the present invention are merely illustrative examples and are not intended to require or imply that the connections, arrangements, configurations must be made in the manner shown in the block diagrams. As will be appreciated by one of skill in the art, the devices, systems, apparatuses, systems may be connected, arranged, configured in any manner. Words such as "including," "comprising," "having," and the like are words of openness and mean "including but not limited to," and are used interchangeably therewith. The terms "or" and "as used herein refer to and are used interchangeably with the term" and/or "unless the context clearly indicates otherwise. The term "such as" as used herein refers to, and is used interchangeably with, the phrase "such as, but not limited to.
The method and system of the present invention may be implemented in a number of ways. For example, the methods and systems of the present invention may be implemented by software, hardware, firmware, or any combination of software, hardware, firmware. The above-described sequence of steps for the method is for illustration only, and the steps of the method of the present invention are not limited to the sequence specifically described above unless specifically stated otherwise. Furthermore, in some embodiments, the present invention may also be embodied as programs recorded in a recording medium, the programs including machine-readable instructions for implementing the methods according to the present invention. Thus, the present invention also covers a recording medium storing a program for executing the method according to the present invention.
It is also noted that in the systems, devices and methods of the present invention, components or steps may be disassembled and/or assembled. Such decomposition and/or recombination should be considered as equivalent aspects of the present invention. The previous description of the disclosed aspects is provided to enable any person skilled in the art to make or use the present invention. Various modifications to these aspects will be readily apparent to those skilled in the art, and the generic principles defined herein may be applied to other aspects without departing from the scope of the invention. Thus, the present invention is not intended to be limited to the aspects shown herein but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.
The foregoing description has been presented for purposes of illustration and description. Furthermore, this description is not intended to limit embodiments of the invention to the form disclosed herein. Although a number of example aspects and embodiments have been discussed above, a person of ordinary skill in the art will recognize certain variations, modifications, alterations, additions, and subcombinations thereof.
Claims (10)
1. A power control stability judging method of a new energy station grid-connected system is characterized by comprising the following steps:
acquiring electrical quantity information of a new energy station grid-connected system through a typical structure diagram of the new energy station grid-connected system, and establishing a Thevenin equivalent circuit according to the electrical quantity information;
determining a grid-connected point voltage formula, an active power output expression and a reactive power output expression of the new energy station grid-connected system according to the Thevenin equivalent circuit based on a power system trend equation and a KVL equation;
decomposing grid-connected point output current of the new energy station grid-connected system under a VSC rotation coordinate system to obtain d-axis current components and q-axis current components of the grid-connected point output current;
bringing the d-axis current component and the q-axis current component into the grid-connected point voltage formula, the active power output expression and the reactive power output expression to determine an active control stability criterion and a reactive control stability criterion of the new energy station grid-connected system;
and determining the power control stability of the grid-connected system of the new energy station according to the active control stability criterion and the reactive control stability criterion.
2. The method of claim 1, wherein the operation of bringing the d-axis current component and the q-axis current component into the grid-tie point voltage formula, the active power output expression, and the reactive power output expression, determining active control stability criteria and reactive control stability criteria for the new energy utility grid-tie system, comprises:
bringing the d-axis current component and the q-axis current component into the grid-connected point voltage formula, the active power output expression and the reactive power output expression, and determining an active power relation and a reactive power relation of active power and reactive power and the d-axis current component and the q-axis current component;
and determining the active control stability criterion and the reactive control stability criterion of the new energy station grid-connected system according to the active power relation and the reactive power relation.
3. The method of claim 2, wherein constructing the active control stability criteria and the reactive control stability criteria for the new energy farm grid-connected system based on the active power relationship and the reactive power relationship comprises:
linearizing the active power relation and the reactive power relation by taking the d-axis current component and the q-axis current component as independent variables, and determining an active power equation and a reactive power equation of the active power and the reactive power and d-axis current component small signals and q-axis current component small signals;
and extracting coefficients of d-axis current component small signals and q-axis current component small signals in the active power equation and the reactive power equation, and determining the active control stability criterion and the reactive control stability criterion.
4. The method of claim 1, wherein determining the stability of the new energy utility grid-tie system based on the active control stability criteria and the reactive control stability criteria comprises:
when R is P And R is Q When the power control stability of the new energy station grid-connected system is greater than a first threshold value, the risk exists;
when R is P And R is Q When the power control of the new energy station grid-connected system is smaller than the first threshold value and larger than the second threshold value, the power control of the new energy station grid-connected system is at an unstable risk;
when R is P And R is Q When the power control of the new energy station grid-connected system is smaller than a second threshold value, the power control of the new energy station grid-connected system is kept stable, wherein R P For active control stabilization criteria, R Q Is a reactive control stability criterion.
5. The utility model provides a power control stability judgement device of new forms of energy station grid-connected system which characterized in that includes:
the building module is used for obtaining the electrical quantity information of the new energy station grid-connected system through a typical structure diagram of the new energy station grid-connected system, and building a Thevenin equivalent circuit according to the electrical quantity information;
the first determining module is used for determining a grid-connected point voltage formula, an active power output expression and a reactive power output expression of the new energy station grid-connected system according to the Thevenin equivalent circuit based on a power system tide equation and a KVL equation;
the decomposition module is used for decomposing the grid-connected point output current of the new energy station grid-connected system under the VSC rotation coordinate system to obtain a d-axis current component and a q-axis current component of the grid-connected point output current;
the second determining module is used for bringing the d-axis current component and the q-axis current component into the grid-connected point voltage formula, the active power output expression and the reactive power output expression to determine an active control stability criterion and a reactive control stability criterion of the new energy station grid-connected system;
and the third determining module is used for determining the power control stability of the new energy station grid-connected system according to the active control stability criterion and the reactive control stability criterion.
6. The apparatus of claim 5, wherein the second determining module comprises:
a first determining submodule for bringing the d-axis current component and the q-axis current component into the grid-connected point voltage formula, the active power output expression and the reactive power output expression, and determining an active power relation and a reactive power relation in which active power and reactive power are related to the d-axis current component and the q-axis current component;
and the second determining submodule is used for determining the active control stability criterion and the reactive control stability criterion of the new energy station grid-connected system according to the active power relation and the reactive power relation.
7. The apparatus of claim 6, wherein the second determination submodule comprises:
a first determining unit configured to linearize the active power relation and the reactive power relation with the d-axis current component and the q-axis current component as arguments, and determine an active power equation and a reactive power equation of the active power and the reactive power and the d-axis current component small signal and the q-axis current component small signal;
and the second determining unit is used for extracting the coefficients of the d-axis current component small signal and the q-axis current component small signal in the active power equation and the reactive power equation and determining the active control stability criterion and the reactive control stability criterion.
8. The apparatus of claim 5, wherein the third determination module comprises:
a first determination sub-module for determining when R P And R is Q When the power control stability of the new energy station grid-connected system is greater than a first threshold value, the risk exists;
a second determination sub-module for determining when R P And R is Q When the power control of the new energy station grid-connected system is smaller than the first threshold value and larger than the second threshold value, the power control of the new energy station grid-connected system is at an unstable risk;
a third determination sub-module for determining when R P And R is Q When the power control of the new energy station grid-connected system is smaller than a second threshold value, the power control of the new energy station grid-connected system is kept stable, wherein R P For active control stabilization criteria, R Q Is a reactive control stability criterion.
9. A computer readable storage medium, characterized in that the storage medium stores a computer program for executing the method of any of the preceding claims 1-4.
10. An electronic device, the electronic device comprising:
a processor;
a memory for storing the processor-executable instructions;
the processor is configured to read the executable instructions from the memory and execute the instructions to implement the method of any of the preceding claims 1-4.
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Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN116629641A (en) * | 2023-07-21 | 2023-08-22 | 沈阳嘉越电力数字化产业技术研究院有限公司 | New energy station grid-connected stability assessment method |
| CN117220296A (en) * | 2023-11-09 | 2023-12-12 | 中国电力科学研究院有限公司 | Power grid voltage stability analysis method and system considering new energy control switching |
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Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN116629641A (en) * | 2023-07-21 | 2023-08-22 | 沈阳嘉越电力数字化产业技术研究院有限公司 | New energy station grid-connected stability assessment method |
| CN116629641B (en) * | 2023-07-21 | 2023-10-03 | 沈阳嘉越电力数字化产业技术研究院有限公司 | New energy station grid-connected stability assessment method |
| CN117220296A (en) * | 2023-11-09 | 2023-12-12 | 中国电力科学研究院有限公司 | Power grid voltage stability analysis method and system considering new energy control switching |
| CN117220296B (en) * | 2023-11-09 | 2024-01-09 | 中国电力科学研究院有限公司 | Power grid voltage stability analysis method and system considering new energy control switching |
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