CN110289633B - Method and device for determining stability of equipment during grid connection - Google Patents

Method and device for determining stability of equipment during grid connection Download PDF

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CN110289633B
CN110289633B CN201910428777.0A CN201910428777A CN110289633B CN 110289633 B CN110289633 B CN 110289633B CN 201910428777 A CN201910428777 A CN 201910428777A CN 110289633 B CN110289633 B CN 110289633B
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matrix
margin
equipment
phase angle
diagonal element
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CN110289633A (en
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陈磊
任怡娜
闵勇
张毅威
徐飞
胡伟
鲁宗相
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Tsinghua University
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    • G—PHYSICS
    • G06—COMPUTING; CALCULATING OR COUNTING
    • G06Q—INFORMATION AND COMMUNICATION TECHNOLOGY [ICT] SPECIALLY ADAPTED FOR ADMINISTRATIVE, COMMERCIAL, FINANCIAL, MANAGERIAL OR SUPERVISORY PURPOSES; SYSTEMS OR METHODS SPECIALLY ADAPTED FOR ADMINISTRATIVE, COMMERCIAL, FINANCIAL, MANAGERIAL OR SUPERVISORY PURPOSES, NOT OTHERWISE PROVIDED FOR
    • G06Q50/00—Systems or methods specially adapted for specific business sectors, e.g. utilities or tourism
    • G06Q50/06—Electricity, gas or water supply
    • 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

Abstract

The embodiment of the invention provides a method and a device for determining the stability of equipment during grid connection, wherein the method comprises the following steps: respectively acquiring electrical parameters of equipment and testing the line conditions of the equipment; respectively acquiring an admittance matrix of the equipment and an impedance matrix of a line according to the electrical parameters and the line conditions, and calculating a return rate matrix of a grid-connected network of the equipment according to the admittance matrix and the impedance matrix; and if the amplitude margin and the phase angle margin corresponding to each diagonal element in the admittance matrix are judged and obtained to be larger than the preset amplitude margin and the preset phase angle margin, determining that the equipment is in an oscillation stable state during grid connection. The device performs the above method. The method and the device for determining the stability of the equipment during grid connection provided by the embodiment of the invention can accurately determine the oscillation stability of the equipment during grid connection.

Description

Method and device for determining stability of equipment during grid connection
Technical Field
The invention relates to the technical field of power electronic equipment, in particular to a method and a device for determining the stability of equipment during grid connection.
Background
In recent years, power electronic devices (i.e., devices) in power systems are widely used, but the devices are prone to oscillation during grid connection, and how to solve the problem is important.
The oscillation analysis method based on the impedance or the admittance matrix is an important analysis method in the prior art, and a plurality of factors influencing the oscillation stability of the equipment during grid connection exist, and the factors considered by the existing oscillation analysis method based on the impedance or the admittance matrix are not comprehensive enough, so that the identification result of the oscillation stability of the equipment during grid connection is not accurate enough, and more practical difficulties are brought to the staff related to the equipment.
Therefore, how to avoid the above-mentioned defects and accurately determine the oscillation stability of the device during grid connection becomes a problem to be solved urgently.
Disclosure of Invention
Aiming at the problems in the prior art, the embodiment of the invention provides a method and a device for determining the stability of equipment during grid connection.
The embodiment of the invention provides a method for determining the stability of equipment during grid connection, which comprises the following steps:
respectively acquiring electrical parameters of equipment and testing the line conditions of the equipment;
respectively acquiring an admittance matrix of the equipment and an impedance matrix of a line according to the electrical parameters and the line conditions, and calculating a return rate matrix of a grid-connected network of the equipment according to the admittance matrix and the impedance matrix;
if the amplitude margin and the phase angle margin corresponding to each diagonal element in the admittance matrix are judged and obtained to be larger than the preset amplitude margin and the preset phase angle margin, determining that the equipment is in an oscillation stable state when grid connection is carried out; the preset amplitude margin and the preset phase angle margin are respectively determined according to each diagonal element in the impedance matrix and the non-diagonal element corresponding to each diagonal element in the return rate matrix.
The embodiment of the invention provides a device for determining the stability of equipment during grid connection, which comprises:
the device comprises an acquisition unit, a control unit and a control unit, wherein the acquisition unit is used for respectively acquiring electrical parameters of equipment and testing line conditions of the equipment;
the calculation unit is used for respectively acquiring an admittance matrix of the equipment and an impedance matrix of the line according to the electrical parameters and the line conditions, and calculating a return rate matrix of a grid-connected network of the equipment according to the admittance matrix and the impedance matrix;
the determining unit is used for determining that the equipment is in an oscillation stable state when grid connection is carried out if the amplitude margin and the phase angle margin corresponding to each diagonal element in the admittance matrix are judged and obtained to be larger than the preset amplitude margin and the preset phase angle margin; the preset amplitude margin and the preset phase angle margin are respectively determined according to each diagonal element in the impedance matrix and the non-diagonal element corresponding to each diagonal element in the return rate matrix.
An embodiment of the present invention provides an electronic device, including: a memory, a processor, and a computer program stored on the memory and executable on the processor, wherein,
the processor, when executing the program, implements the method steps of:
respectively acquiring electrical parameters of equipment and testing the line conditions of the equipment;
respectively acquiring an admittance matrix of the equipment and an impedance matrix of a line according to the electrical parameters and the line conditions, and calculating a return rate matrix of a grid-connected network of the equipment according to the admittance matrix and the impedance matrix;
if the amplitude margin and the phase angle margin corresponding to each diagonal element in the admittance matrix are judged and obtained to be larger than the preset amplitude margin and the preset phase angle margin, determining that the equipment is in an oscillation stable state when grid connection is carried out; the preset amplitude margin and the preset phase angle margin are respectively determined according to each diagonal element in the impedance matrix and the non-diagonal element corresponding to each diagonal element in the return rate matrix.
An embodiment of the invention provides a non-transitory computer readable storage medium having a computer program stored thereon, which when executed by a processor implements the following method steps:
respectively acquiring electrical parameters of equipment and testing the line conditions of the equipment;
respectively acquiring an admittance matrix of the equipment and an impedance matrix of a line according to the electrical parameters and the line conditions, and calculating a return rate matrix of a grid-connected network of the equipment according to the admittance matrix and the impedance matrix;
if the amplitude margin and the phase angle margin corresponding to each diagonal element in the admittance matrix are judged and obtained to be larger than the preset amplitude margin and the preset phase angle margin, determining that the equipment is in an oscillation stable state when grid connection is carried out; the preset amplitude margin and the preset phase angle margin are respectively determined according to each diagonal element in the impedance matrix and the non-diagonal element corresponding to each diagonal element in the return rate matrix.
According to the method and the device for determining the stability of the equipment during grid connection, provided by the embodiment of the invention, the preset amplitude margin and the preset phase angle margin are determined according to the non-diagonal elements corresponding to each diagonal element in the return rate matrix and each diagonal element in the impedance matrix respectively, so that the oscillation stability of the equipment during grid connection can be accurately determined.
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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 used in the description of the embodiments or the prior art will be briefly described below, and it is obvious that the drawings in the following description are some embodiments of the present invention, and those skilled in the art can also obtain other drawings according to the drawings without creative efforts.
FIG. 1 is a flowchart of an embodiment of a method for determining stability of a device during grid connection according to the present invention;
FIG. 2 is a schematic structural diagram of an embodiment of the apparatus for determining stability of a device during grid connection according to the present invention;
fig. 3 is a schematic structural diagram of an electronic device according to an embodiment of the present invention.
Detailed Description
In order to make the objects, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are some, but not all, embodiments of the present invention. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.
Fig. 1 is a flowchart of an embodiment of a method for determining stability of a device during grid connection, and as shown in fig. 1, the method for determining stability of the device during grid connection provided by the embodiment of the present invention includes the following steps:
s101: respectively obtaining the electrical parameters of the equipment and testing the line conditions of the equipment.
Specifically, the device respectively obtains electrical parameters of the equipment and tests line conditions of the equipment. The apparatus may be a device itself, or another device having a connection relationship with the device, and is not particularly limited. The device may be a power electronic device in a power system, and the electrical parameters may include a phase-locked loop, a current loop, and a power loop, without being particularly limited. The line condition of the test equipment is understood to be a line condition required for the equipment test, and is not particularly limited.
S102: and respectively acquiring an admittance matrix of the equipment and an impedance matrix of the line according to the electrical parameters and the line conditions, and calculating a return rate matrix of a grid-connected network of the equipment according to the admittance matrix and the impedance matrix.
Specifically, the device respectively obtains an admittance matrix of the equipment and an impedance matrix of the line according to the electrical parameters and the line conditions, and calculates a rate matrix of the grid-connected network of the equipment according to the admittance matrix and the impedance matrix. It should be noted that: the sequence of the step of obtaining the admittance matrix of the device according to the electrical parameter and the step of obtaining the impedance matrix of the line according to the line condition is not particularly limited. The admittance matrix may be in the dq coordinate system and in the natural coordinate system.
The admittance matrix can be obtained by the following two methods:
the method comprises the following steps: push guide method
A transfer function model of the equipment can be constructed according to specific numerical values of the phase-locked loop, the current loop and the power loop, and then an admittance matrix of the equipment is obtained according to the transfer function model.
The method 2 comprises the following steps: measuring method
And obtaining the admittance matrix of the equipment by adopting a harmonic injection method, namely injecting harmonic currents with different frequencies into the grid-connected point, and measuring the voltage of the grid-connected point, the current flowing into the equipment and the current flowing into the network so as to obtain the admittance matrix of the equipment.
The impedance matrix of the line can be calculated according to the line condition required by the device test, and the specific calculation process is not described in detail for the mature technology in the field.
The admittance matrix, the impedance matrix and the return rate matrix are two-dimensional matrices, and calculating the return rate matrix of the grid-connected network of the device according to the admittance matrix and the impedance matrix may specifically include:
calculating and retaining part of the matrix elements according to the following formula:
Figure BDA0002068316660000051
wherein L is the rate matrix, ZLineIs the impedance matrix, YeIs the admittance matrix; wherein:
Figure BDA0002068316660000052
it should be noted that: for the convenience of subsequent calculation, part of matrix elements need to be discarded, and the reserved part of matrix elements is the ZaaYeaa、ZabYebb、-ZabYeaa、ZbbYebb。
S103: if the amplitude margin and the phase angle margin corresponding to each diagonal element in the admittance matrix are judged and obtained to be larger than the preset amplitude margin and the preset phase angle margin, determining that the equipment is in an oscillation stable state when grid connection is carried out; the preset amplitude margin and the preset phase angle margin are respectively determined according to each diagonal element in the impedance matrix and the non-diagonal element corresponding to each diagonal element in the return rate matrix.
Specifically, if judging that the amplitude margin and the phase angle margin corresponding to each diagonal element in the admittance matrix are larger than the preset amplitude margin and the preset phase angle margin, the device determines that the equipment is in an oscillation stable state during grid connection; the preset amplitude margin and the preset phase angle margin are respectively determined according to each diagonal element in the impedance matrix and the non-diagonal element corresponding to each diagonal element in the return rate matrix. Obtaining the amplitude margin and the phase angle margin corresponding to each diagonal element in the admittance matrix may include: and acquiring a Bode diagram (namely a Bode diagram) of the admittance matrix, and acquiring a magnitude margin and a phase angle margin corresponding to each diagonal element in the admittance matrix according to the Bode diagram.
The predetermined magnitude margin and the predetermined phase angle margin are associated with each diagonal element in the admittance matrix, i.e. diagonal element Y in the admittance matrixeaaThe corresponding preset amplitude margin and the preset phase angle margin are respectively haaAnd gammaaa(ii) a Diagonal element Y in the admittance matrixebbThe corresponding preset amplitude margin and the preset phase angle margin are respectively hbbAnd gammabb。
I.e. YeaaThe corresponding amplitude margin is larger than haa、YeaaCorresponding phase angle margin greater than gammaaa；YebbThe corresponding amplitude margin is larger than hbb、YebbCorresponding phase angle margin greater than gammabbAnd determining that the equipment is in an oscillation stable state when being connected to the grid. For haa、hbb、γaa、γbbCan be calculated according to the following formulas respectively:
haa＝-20lg|1-|Lab||-20lg|Zaa|
wherein h isaaIs a radical of and YeaaCorresponding preset amplitude margin, LabFor ones of said rate matrices corresponding to YeaaL ofaaCorresponding off-diagonal elements, ZaaFor said impedance matrix, corresponding to YeaaA diagonal element of (a);
hbb＝-20lg|1-|Lba||-20lg|Zbb|
wherein h isbbIs a radical of and YebbCorresponding preset amplitude margin, LbaFor ones of said rate matrices corresponding to YebbL ofbbCorresponding off-diagonal elements, ZbbFor said impedance matrix, corresponding to YebbDiagonal elements of (a).
Figure BDA0002068316660000061
Wherein, γaaIs a radical of and YeaaCorresponding predetermined phase angle margin, LabFor ones of said rate matrices corresponding to YeaaL ofaaCorresponding off-diagonal elements, ZaaFor said impedance matrix, corresponding to YeaaA diagonal element of (a);
Figure BDA0002068316660000062
wherein, γbbIs a radical of and YebbCorresponding predetermined phase angle margin, LbaFor ones of said rate matrices corresponding to YebbL ofbbCorresponding off-diagonal elements, ZbbFor said impedance matrix, corresponding to YebbDiagonal elements of (a).
It should be noted that: after the step S103, the following steps may be further included:
in a reasonable value range of parameters to be analyzed (which can comprise the phase-locked loop, the current loop and the power loop), each value is tested to obtain a security domain of equipment parameters, so that the adjustable range of the equipment parameters is obtained on the premise of ensuring the stability.
According to the method for determining the stability of the equipment during grid connection, the preset amplitude margin and the preset phase angle margin are determined according to the non-diagonal elements corresponding to the diagonal elements in the return rate matrix and the diagonal elements in the impedance matrix, and the oscillation stability of the equipment during grid connection can be accurately determined.
On the basis of the above embodiment, the admittance matrix, the impedance matrix and the return rate matrix are all two-dimensional matrices; correspondingly, the calculating a return rate matrix of the grid-connected network of the device according to the admittance matrix and the impedance matrix includes:
calculating and retaining part of the matrix elements according to the following formula:
Figure BDA0002068316660000071
wherein L is the rate matrix, ZLineIs the impedance matrix, YeIs the admittance matrix; wherein:
Figure BDA0002068316660000072
specifically, the apparatus calculates and retains a portion of the matrix elements according to the following formula:
Figure BDA0002068316660000073
wherein L is the rate matrix, ZLineIs the impedance matrix, YeIs the admittance matrix; wherein:
Figure BDA0002068316660000074
reference is made to the above description and no further description is made.
According to the method for determining the stability of the equipment during grid connection, provided by the embodiment of the invention, the rate matrix of the network of the equipment during grid connection is calculated through a specific formula, so that the method can be normally carried out.
On the basis of the above embodiment, each diagonal element in the admittance matrix comprises YeaaAnd Yebb(ii) a Correspondingly, the preset amplitude margin is calculated according to the following formula:
haa＝-20lg|1-|Lab||-20lg|Zaa|
wherein h isaaIs a radical of and YeaaCorresponding preset amplitude margin, LabFor ones of said rate matrices corresponding to YeaaL ofaaCorresponding off-diagonal elements, ZaaFor said impedance matrix, corresponding to YeaaA diagonal element of (a);
hbb＝-20lg|1-|Lba||-20lg|Zbb|
wherein h isbbIs a radical of and YebbCorresponding preset amplitude margin, LbaFor ones of said rate matrices corresponding to YebbL ofbbCorresponding off-diagonal elements, ZbbFor said impedance matrix, corresponding to YebbDiagonal elements of (a).
Specifically, the preset amplitude margin in the device is calculated according to the following formula:
haa＝-20lg|1-|Lab||-20lg|Zaa|
wherein h isaaIs a radical of and YeaaCorresponding preset amplitude margin, LabFor ones of said rate matrices corresponding to YeaaL ofaaCorresponding off-diagonal elements, ZaaFor said impedance matrix, corresponding to YeaaA diagonal element of (a);
hbb＝-20lg|1-|Lba||-20lg|Zbb|
wherein h isbbIs a radical of and YebbCorresponding predetermined marginDegree, LbaFor ones of said rate matrices corresponding to YebbL ofbbCorresponding off-diagonal elements, ZbbFor said impedance matrix, corresponding to YebbDiagonal elements of (a). Reference is made to the above description and no further description is made.
According to the method for determining the stability of the equipment during grid connection, provided by the embodiment of the invention, the preset amplitude margin is calculated through a specific formula, so that the oscillation stability of the equipment during grid connection can be further accurately determined.
On the basis of the above embodiment, the preset phase angle margin is calculated according to the following formula:
Figure BDA0002068316660000081
wherein, γaaIs a radical of and YeaaCorresponding predetermined phase angle margin, LabFor ones of said rate matrices corresponding to YeaaL ofaaCorresponding off-diagonal elements, ZaaFor said impedance matrix, corresponding to YeaaA diagonal element of (a);
Figure BDA0002068316660000082
wherein, γbbIs a radical of and YebbCorresponding predetermined phase angle margin, LbaFor ones of said rate matrices corresponding to YebbL ofbbCorresponding off-diagonal elements, ZbbFor said impedance matrix, corresponding to YebbDiagonal elements of (a).
Specifically, the preset phase angle margin in the device is calculated according to the following formula:
Figure BDA0002068316660000083
wherein, γaaIs a radical of and YeaaCorresponding predetermined phase angle margin, LabFor pairs in the rate matrixCorresponding to YeaaL ofaaCorresponding off-diagonal elements, ZaaFor said impedance matrix, corresponding to YeaaA diagonal element of (a);
Figure BDA0002068316660000084
wherein, γbbIs a radical of and YebbCorresponding predetermined phase angle margin, LbaFor ones of said rate matrices corresponding to YebbL ofbbCorresponding off-diagonal elements, ZbbFor said impedance matrix, corresponding to YebbDiagonal elements of (a). Reference is made to the above description and no further description is made.
According to the method for determining the stability of the equipment during grid connection, provided by the embodiment of the invention, the preset phase angle margin is calculated through a specific formula, so that the oscillation stability of the equipment during grid connection can be further accurately determined.
On the basis of the foregoing embodiment, the obtaining of the amplitude margin and the phase angle margin corresponding to each diagonal element in the admittance matrix includes:
and acquiring a bode diagram of the admittance matrix, and acquiring an amplitude margin and a phase angle margin corresponding to each diagonal element in the admittance matrix according to the bode diagram.
Specifically, the device acquires a bode diagram of the admittance matrix, and acquires a magnitude margin and a phase angle margin corresponding to each diagonal element in the admittance matrix according to the bode diagram. Reference is made to the above description and no further description is made.
According to the method for determining the stability of the equipment during grid connection, the amplitude margin and the phase angle margin corresponding to each diagonal element in the admittance matrix are obtained through the Bode diagram, and the method can be guaranteed to be normally carried out.
On the basis of the foregoing embodiment, the obtaining an admittance matrix of the device includes:
and obtaining the admittance matrix of the equipment by adopting a harmonic injection method.
Specifically, the device obtains the admittance matrix of the equipment by adopting a harmonic injection method. Reference is made to the above description and no further description is made.
According to the method for determining the stability of the equipment during grid connection, the admittance matrix of the equipment is obtained by adopting the harmonic injection method, so that the method can be ensured to be normally carried out.
Fig. 2 is a schematic structural diagram of an apparatus for determining stability of a device during grid connection, and as shown in fig. 2, an embodiment of the present invention provides an apparatus for determining stability of a device during grid connection, including an obtaining unit 201, a calculating unit 202, and a determining unit 203, where:
the acquiring unit 201 is configured to acquire an electrical parameter of a device and test a line condition of the device, respectively; the calculation unit 202 is configured to obtain an admittance matrix of the device and an impedance matrix of the line according to the electrical parameter and the line condition, and calculate a rate matrix of a grid-connected network of the device according to the admittance matrix and the impedance matrix; the determining unit 203 is configured to determine that the device is in an oscillation stable state when grid connection is performed if it is judged and known that the amplitude margin and the phase angle margin corresponding to each diagonal element in the admittance matrix are both greater than a preset amplitude margin and a preset phase angle margin; the preset amplitude margin and the preset phase angle margin are respectively determined according to each diagonal element in the impedance matrix and the non-diagonal element corresponding to each diagonal element in the return rate matrix.
Specifically, the obtaining unit 201 is configured to obtain electrical parameters of the device and test line conditions of the device; the calculation unit 202 is configured to obtain an admittance matrix of the device and an impedance matrix of the line according to the electrical parameter and the line condition, and calculate a rate matrix of a grid-connected network of the device according to the admittance matrix and the impedance matrix; the determining unit 203 is configured to determine that the device is in an oscillation stable state when grid connection is performed if it is judged and known that the amplitude margin and the phase angle margin corresponding to each diagonal element in the admittance matrix are both greater than a preset amplitude margin and a preset phase angle margin; the preset amplitude margin and the preset phase angle margin are respectively determined according to each diagonal element in the impedance matrix and the non-diagonal element corresponding to each diagonal element in the return rate matrix.
According to the device for determining the stability of the equipment during grid connection, provided by the embodiment of the invention, the preset amplitude margin and the preset phase angle margin are determined according to the non-diagonal elements corresponding to each diagonal element in the return rate matrix and each diagonal element in the impedance matrix respectively, so that the oscillation stability of the equipment during grid connection can be accurately determined.
The device for determining the stability of the device during grid connection provided by the embodiment of the present invention may be specifically configured to execute the processing flows of the above method embodiments, and the functions of the device are not described herein again, and reference may be made to the detailed description of the method embodiments.
Fig. 3 is a schematic structural diagram of an electronic device according to an embodiment of the present invention, and as shown in fig. 3, the electronic device includes: a processor (processor)301, a memory (memory)302, and a bus 303;
the processor 301 and the memory 302 complete communication with each other through a bus 303;
the processor 301 is configured to call program instructions in the memory 302 to perform the methods provided by the above-mentioned method embodiments, including: respectively acquiring electrical parameters of equipment and testing the line conditions of the equipment; respectively acquiring an admittance matrix of the equipment and an impedance matrix of a line according to the electrical parameters and the line conditions, and calculating a return rate matrix of a grid-connected network of the equipment according to the admittance matrix and the impedance matrix; if the amplitude margin and the phase angle margin corresponding to each diagonal element in the admittance matrix are judged and obtained to be larger than the preset amplitude margin and the preset phase angle margin, determining that the equipment is in an oscillation stable state when grid connection is carried out; the preset amplitude margin and the preset phase angle margin are respectively determined according to each diagonal element in the impedance matrix and the non-diagonal element corresponding to each diagonal element in the return rate matrix.
The present embodiment discloses a computer program product comprising a computer program stored on a non-transitory computer readable storage medium, the computer program comprising program instructions which, when executed by a computer, enable the computer to perform the method provided by the above-mentioned method embodiments, for example, comprising: respectively acquiring electrical parameters of equipment and testing the line conditions of the equipment; respectively acquiring an admittance matrix of the equipment and an impedance matrix of a line according to the electrical parameters and the line conditions, and calculating a return rate matrix of a grid-connected network of the equipment according to the admittance matrix and the impedance matrix; if the amplitude margin and the phase angle margin corresponding to each diagonal element in the admittance matrix are judged and obtained to be larger than the preset amplitude margin and the preset phase angle margin, determining that the equipment is in an oscillation stable state when grid connection is carried out; the preset amplitude margin and the preset phase angle margin are respectively determined according to each diagonal element in the impedance matrix and the non-diagonal element corresponding to each diagonal element in the return rate matrix.
The present embodiments provide a non-transitory computer-readable storage medium storing computer instructions that cause the computer to perform the methods provided by the above method embodiments, for example, including: respectively acquiring electrical parameters of equipment and testing the line conditions of the equipment; respectively acquiring an admittance matrix of the equipment and an impedance matrix of a line according to the electrical parameters and the line conditions, and calculating a return rate matrix of a grid-connected network of the equipment according to the admittance matrix and the impedance matrix; if the amplitude margin and the phase angle margin corresponding to each diagonal element in the admittance matrix are judged and obtained to be larger than the preset amplitude margin and the preset phase angle margin, determining that the equipment is in an oscillation stable state when grid connection is carried out; the preset amplitude margin and the preset phase angle margin are respectively determined according to each diagonal element in the impedance matrix and the non-diagonal element corresponding to each diagonal element in the return rate matrix.
Those of ordinary skill in the art will understand that: all or part of the steps for implementing the method embodiments may be implemented by hardware related to program instructions, and the program may be stored in a computer readable storage medium, and when executed, the program performs the steps including the method embodiments; and the aforementioned storage medium includes: various media that can store program codes, such as ROM, RAM, magnetic or optical disks.
The above-described embodiments of the apparatus are merely illustrative, and the units described as separate parts may or may not be physically separate, and parts displayed as units may or may not be physical units, may be located in one place, or may be distributed on a plurality of network units. Some or all of the modules may be selected according to actual needs to achieve the purpose of the solution of the present embodiment. One of ordinary skill in the art can understand and implement it without inventive effort.
Through the above description of the embodiments, those skilled in the art will clearly understand that each embodiment can be implemented by software plus a necessary general hardware platform, and certainly can also be implemented by hardware. With this understanding in mind, the above-described technical solutions may be embodied in the form of a software product, which can be stored in a computer-readable storage medium such as ROM/RAM, magnetic disk, optical disk, etc., and includes instructions for causing a computer device (which may be a personal computer, a server, or a network device, etc.) to execute the methods described in the embodiments or some parts of the embodiments.
Finally, it should be noted that: the above examples are only intended to illustrate the technical solution of the present invention, but not to limit it; although the present invention has been described in detail with reference to the foregoing embodiments, it will be understood by those of ordinary skill in the art that: the technical solutions described in the foregoing embodiments may still be modified, or some technical features may be equivalently replaced; and such modifications or substitutions do not depart from the spirit and scope of the corresponding technical solutions of the embodiments of the present invention.

Claims (6)

1. A method for determining stability of equipment during grid connection is characterized by comprising the following steps:
respectively acquiring electrical parameters of equipment and testing the line conditions of the equipment;
respectively acquiring an admittance matrix of the equipment and an impedance matrix of a line according to the electrical parameters and the line conditions, and calculating a return rate matrix of a grid-connected network of the equipment according to the admittance matrix and the impedance matrix;
the admittance matrix, the impedance matrix and the return rate matrix are two-dimensional matrices; correspondingly, the calculating a return rate matrix of the grid-connected network of the device according to the admittance matrix and the impedance matrix includes:
calculating and retaining part of the matrix elements according to the following formula:
Figure FDA0002965584720000011
wherein L is the rate matrix, ZLineIs the impedance matrix, YeIs the admittance matrix; wherein:
Figure FDA0002965584720000012
if the amplitude margin and the phase angle margin corresponding to each diagonal element in the admittance matrix are judged and obtained to be larger than the preset amplitude margin and the preset phase angle margin, determining that the equipment is in an oscillation stable state when grid connection is carried out; wherein the preset amplitude margin and the preset phase angle margin are respectively determined according to each diagonal element in the impedance matrix and the off-diagonal element corresponding to each diagonal element in the return rate matrix;
each diagonal element in the admittance matrix comprises YeaaAnd Yebb(ii) a Accordingly, the predetermined amplitude margin is based onThe following formula calculates:
haa＝-20lg|1-|Lab||-20lg|Zaa|
wherein h isaaIs a radical of and YeaaCorresponding preset amplitude margin, LabFor ones of said rate matrices corresponding to YeaaL ofaaCorresponding off-diagonal elements, ZaaFor said impedance matrix, corresponding to YeaaA diagonal element of (a);
hbb＝-20lg|1-|Lba||-20lg|Zbb|
wherein h isbbIs a radical of and YebbCorresponding preset amplitude margin, LbaFor ones of said rate matrices corresponding to YebbL ofbbCorresponding off-diagonal elements, ZbbFor said impedance matrix, corresponding to YebbA diagonal element of (a);
the preset phase angle margin is calculated according to the following formula:
Figure FDA0002965584720000021
wherein, γaaIs a radical of and YeaaCorresponding predetermined phase angle margin, LabFor ones of said rate matrices corresponding to YeaaL ofaaCorresponding off-diagonal elements, ZaaFor said impedance matrix, corresponding to YeaaA diagonal element of (a);
Figure FDA0002965584720000022
wherein, γbbIs a radical of and YebbCorresponding predetermined phase angle margin, LbaFor ones of said rate matrices corresponding to YebbL ofbbCorresponding off-diagonal elements, ZbbFor said impedance matrix, corresponding to YebbDiagonal elements of (a).
2. The method for determining the stability of the device during grid connection according to claim 1, wherein the obtaining of the amplitude margin and the phase angle margin corresponding to each diagonal element in the admittance matrix comprises:
and acquiring a bode diagram of the admittance matrix, and acquiring an amplitude margin and a phase angle margin corresponding to each diagonal element in the admittance matrix according to the bode diagram.
3. The method for determining the stability of the equipment during grid connection according to claim 1, wherein the obtaining of the admittance matrix of the equipment comprises:
and obtaining the admittance matrix of the equipment by adopting a harmonic injection method.
4. An apparatus for determining stability of a device during grid connection is characterized by comprising:
the device comprises an acquisition unit, a control unit and a control unit, wherein the acquisition unit is used for respectively acquiring electrical parameters of equipment and testing line conditions of the equipment;
the calculation unit is used for respectively acquiring an admittance matrix of the equipment and an impedance matrix of the line according to the electrical parameters and the line conditions, and calculating a return rate matrix of a grid-connected network of the equipment according to the admittance matrix and the impedance matrix;
the admittance matrix, the impedance matrix and the return rate matrix are two-dimensional matrices; correspondingly, the calculating a return rate matrix of the grid-connected network of the device according to the admittance matrix and the impedance matrix includes:
calculating and retaining part of the matrix elements according to the following formula:
Figure FDA0002965584720000031
wherein L is the rate matrix, ZLineIs the impedance matrix, YeIs the admittance matrix; wherein:
Figure FDA0002965584720000032
the determining unit is used for determining that the equipment is in an oscillation stable state when grid connection is carried out if the amplitude margin and the phase angle margin corresponding to each diagonal element in the admittance matrix are judged and obtained to be larger than the preset amplitude margin and the preset phase angle margin; wherein the preset amplitude margin and the preset phase angle margin are respectively determined according to each diagonal element in the impedance matrix and the off-diagonal element corresponding to each diagonal element in the return rate matrix;
each diagonal element in the admittance matrix comprises YeaaAnd Yebb(ii) a Correspondingly, the preset amplitude margin is calculated according to the following formula:
haa＝-20lg|1-|Lab||-20lg|Zaa|
wherein h isaaIs a radical of and YeaaCorresponding preset amplitude margin, LabFor ones of said rate matrices corresponding to YeaaL ofaaCorresponding off-diagonal elements, ZaaFor said impedance matrix, corresponding to YeaaA diagonal element of (a);
hbb＝-20lg|1-|Lba||-20lg|Zbb|
wherein h isbbIs a radical of and YebbCorresponding preset amplitude margin, LbaFor ones of said rate matrices corresponding to YebbL ofbbCorresponding off-diagonal elements, ZbbFor said impedance matrix, corresponding to YebbA diagonal element of (a);
the preset phase angle margin is calculated according to the following formula:
Figure FDA0002965584720000034
wherein, γaaIs a radical of and YeaaCorresponding predetermined phase angle margin, LabFor ones of said rate matrices corresponding to YeaaL ofaaCorresponding off-diagonal elements, ZaaFor said impedance matrix, corresponding to YeaaA diagonal element of (a);
Figure FDA0002965584720000033
wherein, γbbIs a radical of and YebbCorresponding predetermined phase angle margin, LbaFor ones of said rate matrices corresponding to YebbL ofbbCorresponding off-diagonal elements, ZbbFor said impedance matrix, corresponding to YebbDiagonal elements of (a).
5. An electronic device comprising a memory, a processor and a computer program stored on the memory and executable on the processor, characterized in that the steps of the method according to any of claims 1 to 3 are implemented when the processor executes the program.
6. A non-transitory computer-readable storage medium, on which a computer program is stored, which, when being executed by a processor, carries out the steps of the method according to any one of claims 1 to 3.
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Citations (1)

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Publication number Priority date Publication date Assignee Title
CN107994606A (en) * 2017-11-27 2018-05-04 浙江大学 Grid-connected inverter system method for analyzing stability under a kind of multi-frequency coupling factor Coexistence Situation

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CN107994606A (en) * 2017-11-27 2018-05-04 浙江大学 Grid-connected inverter system method for analyzing stability under a kind of multi-frequency coupling factor Coexistence Situation

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