CN111654016B - Method and system suitable for distributed direct-current power grid stability analysis - Google Patents

Method and system suitable for distributed direct-current power grid stability analysis Download PDF

Info

Publication number
CN111654016B
CN111654016B CN202010437133.0A CN202010437133A CN111654016B CN 111654016 B CN111654016 B CN 111654016B CN 202010437133 A CN202010437133 A CN 202010437133A CN 111654016 B CN111654016 B CN 111654016B
Authority
CN
China
Prior art keywords
power grid
current power
distributed
stability
transfer function
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Active
Application number
CN202010437133.0A
Other languages
Chinese (zh)
Other versions
CN111654016A (en
Inventor
林程
孙建侠
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Beijing Institute of Technology BIT
Original Assignee
Beijing Institute of Technology BIT
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Beijing Institute of Technology BIT filed Critical Beijing Institute of Technology BIT
Priority to CN202010437133.0A priority Critical patent/CN111654016B/en
Publication of CN111654016A publication Critical patent/CN111654016A/en
Application granted granted Critical
Publication of CN111654016B publication Critical patent/CN111654016B/en
Active legal-status Critical Current
Anticipated expiration legal-status Critical

Links

Images

Classifications

    • 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
    • H02J1/00—Circuit arrangements for dc mains or dc distribution networks
    • G—PHYSICS
    • G06—COMPUTING; CALCULATING OR COUNTING
    • G06F—ELECTRIC DIGITAL DATA PROCESSING
    • G06F30/00—Computer-aided design [CAD]
    • G06F30/20—Design optimisation, verification or simulation
    • G—PHYSICS
    • G06—COMPUTING; CALCULATING OR COUNTING
    • G06F—ELECTRIC DIGITAL DATA PROCESSING
    • G06F2113/00—Details relating to the application field
    • G06F2113/04—Power grid distribution networks
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02J—CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
    • H02J2203/00—Indexing scheme relating to details of circuit arrangements for AC mains or AC distribution networks
    • H02J2203/10—Power transmission or distribution systems management focussing at grid-level, e.g. load flow analysis, node profile computation, meshed network optimisation, active network management or spinning reserve management
    • 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
    • H02J2203/00—Indexing scheme relating to details of circuit arrangements for AC mains or AC distribution networks
    • H02J2203/20—Simulating, e g planning, reliability check, modelling or computer assisted design [CAD]

Abstract

The invention provides a method and a system suitable for distributed direct current power grid stability analysis, wherein the method comprises the following steps: establishing a mathematical model of a distributed direct-current power grid and a transfer function of bus voltage of the distributed direct-current power grid; based on the Nyquist theorem, a system stability judgment method is provided; and according to the system stability judgment method, analyzing a transfer function of the bus voltage of the distributed direct-current power grid, and determining a stable condition of the bus voltage. According to the method, the method for judging the stability of the system is obtained by establishing the transfer function model of the system and according to the property of the closed-loop transfer function, the method is applied to the stability analysis of the distributed direct-current power grid, the stable condition of the system when a plurality of CPLs are connected in parallel is obtained, and the conclusion is suitable for being used in the stability analysis of the systemnThe order system solves the stability problem of the distributed direct-current power grid and provides a basis for the actual design of the distributed direct-current power grid.

Description

Method and system suitable for distributed direct-current power grid stability analysis
Technical Field
The invention relates to the field of stability analysis, in particular to a method and a system suitable for distributed direct-current power grid stability analysis.
Background
The dc power grid has the advantages of high availability, high density, high efficiency, etc., and is more suitable for integration of energy storage systems or energy sources than conventional ac power systems. Despite the above advantages, dc power systems also have stability problems. In general, a dc power system has a distributed structure, integrating dc loads, power sources, energy storage devices, and the like, in which power electronic converters as interfaces are widely used to realize voltage conversion, and among these converters, a converter employing double closed-loop control and its associated loads are represented as Constant Power Loads (CPL). Due to the negative impedance characteristic of the CPL, a challenge is provided for the stable operation of the direct current power system, the stability margin of the system is reduced, and even the stable operation of the system is damaged. In practical applications, the instability can cause the bus voltage to collapse or oscillate. From the operation point of view, the quality of the dc bus voltage is a main significant feature of the dc power system, and the performance of the dc bus voltage directly affects the reliable operation of the dc power system, so that the guarantee of the voltage stability is the primary objective of the operation.
Currently, the system stability may be determined according to the laus (Routh) criterion, the Nyquist (Nyquist) criterion, or the root-trace method. The Routh criterion is generally used for system stability analysis with determined parameters, the influence of parameter change on stability cannot be analyzed, and absolute stability information is provided. The Nyquist criterion is generally used for analyzing the stability of the system when the parameters change, and can provide a basis for designing the parameters of the system, and relatively stable information is provided. The root trace method is generally used for analyzing the influence of parameter change on system stability, and only trends can be analyzed, but boundary conditions cannot be provided. However, these methods are generally used for stability analysis of a single-power single-load cascaded system, and for a distributed dc power grid, a plurality of loads are connected in parallel on a bus, and it is difficult to apply these methods to stability analysis. Therefore, the invention provides a stability analysis method based on a transfer function model, which is used for analyzing the stability of a distributed direct current power grid.
Disclosure of Invention
In order to solve the technical problems, the invention provides a method and a system suitable for analyzing the stability of a distributed direct current power grid.
The first aspect of the present invention provides a method suitable for analyzing the stability of a distributed dc power grid, including the steps of:
establishing a mathematical model of the distributed direct-current power grid and a transfer function of a bus of the distributed direct-current power grid;
based on Nquist theorem, a system stability judgment method is provided;
and according to the system stability judgment method, analyzing a transfer function of the bus voltage of the distributed direct-current power grid, and determining a stable condition of the bus voltage.
Preferably, the mathematical model of the distributed dc power grid is: impedance Z of power supply sidesEquivalent to resistance RsAnd an inductance LsThe load front-end filter is equivalent to a resistor RLiInductor LiAnd a capacitor CiThe constant power load CPL is equivalent to a negative resistance-RiThe transfer function of the bus voltage of the distributed direct-current power grid is as follows:
Figure BDA0002502692750000021
wherein U isdcFor bus voltage, UsIs the supply voltage, Y∑For the total load admittance in parallel on the bus,
Figure BDA0002502692750000022
n is the number of CPL connected in parallel on the bus, i is 1, 2, …, n.
In any of the foregoing aspects, preferably, the method for determining system stability based on the Nquist theorem includes:
establishing a complex domain model of the system, and using a system closed-loop transfer function G1c(s) defining input-output relationships of the system;
setting the system closed loop transfer function G1c(s) satisfies the preconditions: A. all zeros are positioned on the left half plane of the s plane, B has no pole on the virtual axis of the s plane, and C, the denominator and the numerator of the transfer function are of the same order;
determining a system stable condition D according to the Nyquist contour mapping theorem,
Figure BDA0002502692750000031
Wherein
Figure BDA0002502692750000032
Represents G1cPhase angle of(s), M represents G1c(s) an end point of the curve, M being greater than 0 indicates that the end point is on the positive real axis, and M being less than 0 indicates that the end point M is on the negative real axis.
In any of the foregoing aspects, preferably, according to the system stability determination method, analyzing a transfer function of the distributed dc power grid bus voltage includes:
transfer function G according to bus voltage of distributed direct current power gridc(s) the condition A is required to be met, all closed loop zero points are located on the left half plane of the s plane, and the stable condition 1 of the distributed direct-current power grid is determined;
transfer function G according to bus voltage of distributed direct current power gridc(s) determining a stable condition 2 of the distributed direct-current power grid when the condition B is required to be met and no closed-loop pole exists on an imaginary axis of an s plane;
transfer function G according to bus voltage of distributed direct current power gridc(s) determining a stable condition 3 of the distributed direct-current power grid by satisfying the condition C and ensuring that the denominator and the numerator of the closed-loop transfer function are in the same order;
transfer function G according to bus voltage of distributed direct current power gridc(s) satisfies the condition D,
Figure BDA0002502692750000033
Determining a stable condition 4 of the distributed direct current power grid;
synthesizing the stable condition 1, the stable condition 2, the stable condition 3 and the stable condition 4 to determine the comprehensive stable condition of the distributed direct current power grid, and determining the transfer function G of the voltage of the bus of the distributed direct current power gridc(s) when the comprehensive stability condition is met, the system is stable to a certain extent;
and analyzing the stability of the distributed direct current power grid according to the comprehensive stability condition of the distributed direct current power grid.
In any of the above embodiments, it is preferred that the transfer function G is dependent on the bus voltage of the distributed dc networkc(s) the condition A needs to be met, all the zero points are located on the left half plane of the s plane, and the stable condition 1 of the distributed direct-current power grid is determined as follows:
Figure BDA0002502692750000034
in any of the above embodiments, it is preferred that the transfer function G is dependent on the bus voltage of the distributed dc networkc(s) determining the distribution by satisfying the condition B and having no pole on the imaginary axis of the s-planeThe stable condition 2 of the dc grid is:
Figure BDA0002502692750000041
and R iss<|R∑|。
In any of the above embodiments, it is preferred that the transfer function G is dependent on the bus voltage of the distributed dc networkc(s) condition C, that the denominator and the numerator of the transfer function are in the same order, is satisfied, and the stability condition 3 of the distributed direct current power grid is determined to be unlimited.
In any of the above embodiments, it is preferred that the transfer function G is dependent on the bus voltage of the distributed dc networkc(s)) satisfies the condition D,
Figure BDA0002502692750000042
The stability condition 4 of the distributed dc grid is determined to be unlimited.
In any of the above schemes, preferably, the stable condition 1, the stable condition 2, the stable condition 3 and the stable condition 4 are integrated, and the integrated stable condition of the distributed dc power grid is determined as
Figure BDA0002502692750000043
The second aspect of the present invention provides a system for analyzing the stability of a distributed dc power grid, which is configured to operate the method for analyzing the stability of a distributed dc power grid, so as to analyze the stability of the distributed dc power grid.
By adopting the method and the system suitable for the stability analysis of the distributed direct current power grid, the system stability judgment method is provided according to the property of the closed loop transfer function by establishing the transfer function model of the system, and is applied to the distributed direct current power grid, so that the stability condition of the system when a plurality of CPLs are connected in parallel is obtained, and the conclusion is suitable for an n-order system, the stability problem of the distributed direct current power grid is solved, and the basis is provided for the actual design of the distributed direct current power grid. The stability analysis method provided by the invention is also suitable for other direct current systems with distributed structures.
Drawings
Fig. 1 is a schematic flow diagram of a method for analyzing the stability of a distributed dc power grid according to the present invention.
Fig. 2 is a diagram of an equivalent circuit of a distributed dc power grid suitable for the method for analyzing the stability of the distributed dc power grid according to the present invention.
FIG. 3 is a G of system stability and instability of the method for analyzing the stability of the distributed DC power grid according to the present invention1c(s) graph.
Fig. 4 is a simplified circuit diagram and a norton equivalent circuit diagram of a method ω 0 for distributed dc grid stability analysis according to the present invention.
Detailed Description
For a better understanding of the present invention, reference will now be made in detail to the following examples.
Example 1
As shown in fig. 1, a method for analyzing the stability of a distributed dc power grid includes the steps of:
s1, establishing a mathematical model of the distributed direct-current power grid and a transfer function of the bus voltage of the distributed direct-current power grid;
s2, providing a system stability judgment method based on the Nyquist theorem;
and S3, analyzing the transfer function of the bus voltage of the distributed direct-current power grid according to the system stability judgment method, and determining the stable condition of the bus voltage.
Because the actual direct current power grid is a complex nonlinear system, the system is simplified, fig. 2 shows an equivalent circuit diagram of the distributed direct current power grid, the loads connected in parallel with the buses are all CPLs, and the front end of each CPL is connected with an LC filter. In step S1, the mathematical model of the distributed dc power grid is established as follows: impedance Z of power supply sidesEquivalent to resistance RsAnd an inductance LsThe load front-end filter is equivalent to a resistor RLiInductor LiAnd a capacitor CiThe constant power load CPL is equivalent to a negative resistance-RiAccording to the circuit principle, with bus voltageUdcFor output, the supply voltage UsFor an input object, a transfer function of the bus voltage of the distributed direct current power grid is expressed as:
Figure BDA0002502692750000051
wherein Y is∑For the total load admittance in parallel on the bus,
Figure BDA0002502692750000061
n is the number of CPL connected in parallel on the bus, i is 1, 2, …, n.
In step S2, based on the Nyquist theorem, the method for determining system stability includes the steps of:
s21, establishing a complex domain model of the system, and using a system closed loop transfer function G1c(s) defining the input-output relationship of the system, wherein
Figure BDA0002502692750000062
Wherein z is1，z2，…，zmRepresents G1cM zeros, λ, of(s)1，λ2，…，λnRepresents G1cN poles of(s).
S22, setting the system closed loop transfer function G1c(s) satisfies the preconditions: A. all zeros are located in the left half plane of the s-plane, B, there is no pole on the imaginary axis of the s-plane, and C, the denominator and the numerator of the transfer function are of the same order.
S23, determining a system stable condition D according to the Nyquist contour mapping theorem,
Figure BDA0002502692750000063
Wherein
Figure BDA0002502692750000064
Represents G1cPhase angle of(s), M represents G1c(s) an end point of the curve, M being greater than 0 indicates that the end point is on the positive real axis, and M being less than 0 indicates that the end point M is on the negative real axis.
In step S23In (1), the Nyquist contour of the s-plane is divided into three parts, namely a low-frequency part: s is 0 and corresponds to G1c(s) starting point K, since s is not G when s is 01cZero or pole of(s), so K is a non-0 and finite real number, so G1cThe starting point K of the(s) curve is located on the real axis. An intermediate frequency part: j ω, G since there is no zero or pole on the imaginary axis1cThe magnitude of(s) is not 0 and finite. High-frequency part: s ═ infinity, corresponding to G1cEnd point M of(s) due to G1cThe denominator and the numerator of(s) are of the same order, so that M is not 0 and finite, and the end point M lies on the real axis. (2) The Nyquist contour mapping theorem is applied on the premise that the Nyquist trajectory does not contain any zero pole, the Nyquist contour trajectory of the s-plane is corrected by applying the Nyquist contour mapping theorem, a semicircle with a radius rho approaching infinity replaces an infinite radius circle on the s-plane, and the corrected Nyquist contour trajectory has a radius large enough and tends to infinity, and does not contain zero points and poles. (3) According to the Nyquist contour mapping theorem, G1cThe number of times the(s) curve surrounds the origin is equal to the difference between the poles-zero numbers contained in the Nyquist contour trace, and the Nyquist curve should not contain poles according to the system stability requirement, and because the s-right half contains no zero, G is therefore1cThe number of times the(s) curve should be around the origin should be 0, thus G1cAll intersections of the(s) curve with the real axis should be located on either the positive or negative real axis, otherwise, if G is1cThe intersections of the(s) curves with the real axes being located in different real half axes, then G1cThe(s) curve must surround the origin and the system must be unstable. FIG. 3 shows G in the case of system stabilization and system instability1c(s) graph, FIG. 3(a) shows G1cThe intersection points of the(s) curve and the real axis are all located on the same real half axis, the system is stable, and G is shown in FIG. 3(b)1cThe intersection points of the(s) curve and the real axis are all positioned on different real half axes, surround the origin, and the system is unstable. (4) Because of G1c(s) start point K and end point M are both on the real axis, then G1c(s) the starting point K and the end point M are G1c(s) intersection of the curve with the real axis, G if M is located on the positive real axis1cPhase angle of(s)
Figure BDA0002502692750000071
Should always be unequal to + -180 deg. to ensure G1c(s) the intersection of the curve and the real axis is not located on the negative real axis; if M is located on the negative solid axis, G1cPhase angle of(s)
Figure BDA0002502692750000072
Should always be unequal to 0 ° to ensure G1cThe intersection of the(s) curve with the real axis is not located on the positive real axis, and therefore the system stability condition can be expressed as:
Figure BDA0002502692750000073
meanwhile, K can be determined to be positioned on the positive real axis when M is positioned on the positive real axis, K is also positioned on the negative real axis when M is positioned on the negative real axis, and G is not1cThe(s) curve will enclose the origin, leading to a destabilization of the system.
In step 3, according to the system stability determination method, analyzing a transfer function of the bus voltage of the distributed direct-current power grid, and determining a stability condition of the bus voltage of the distributed direct-current power grid comprises the following steps:
s31 transfer function G according to bus voltage of distributed direct current power gridc(s) determining a stable condition 1 of the distributed direct-current power grid when the condition A is required to be met and all zero points are located on the left half plane of the s plane;
s32 transfer function G according to bus voltage of distributed direct current power gridc(s) determining a stable condition 2 of the distributed direct-current power grid if the condition B is required to be met and no pole exists on an imaginary axis of an s plane;
s33 transfer function G according to bus voltage of distributed direct current power gridc(s) determining a stable condition 3 of the distributed direct current power grid by satisfying the condition C and enabling the denominator and the numerator of the transfer function to be in the same order;
s34 transfer function G according to bus voltage of distributed direct current power gridc(s) satisfies the condition D,
Figure BDA0002502692750000081
Determining a stable condition 4 of the distributed direct current power grid;
and S35, synthesizing the stable condition 1, the stable condition 2, the stable condition 3 and the stable condition 4, and determining the comprehensive stable condition of the distributed direct current power grid.
Step 3 may further comprise the steps of:
and S36, analyzing the stability of the distributed direct current power grid according to the comprehensive stable condition of the distributed direct current power grid.
In step S31, transfer function G is performed according to the bus voltage of the distributed dc power gridc(s) the condition A needs to be met, all the zero points are located on the left half plane of the s plane, and the stable condition 1 of the distributed direct-current power grid is determined as follows:
Figure BDA0002502692750000082
from the expression, G can be determinedcZero point of(s) is Fi(s) pole, GcZero point of(s) is located in the left half plane of the s-plane, then FiThe pole of(s) is located in the left half of the s-plane, and therefore needs to be
Figure BDA0002502692750000083
When each CPL branch meets the condition, the stability of the capacitance voltage of the direct current end can be ensured.
In step S32, transfer function G is performed according to the bus voltage of the distributed dc power gridc(s) the condition B is satisfied, no pole exists on the imaginary axis of the s plane, and the stable condition 2 of the distributed direct current power grid is determined as
Figure BDA0002502692750000084
And R iss<|R∑|。
To satisfy the conditions B, Gc(s) has no pole on the imaginary axis of the s-plane, so that when s is shifted on the imaginary axis, GcThe denominator of(s) should not be 0, and equation conversion is performed to substitute s as j ω into GcExpression of(s) Gc(s) conversion to Gc(j ω), then s moves on the imaginary axis, GcThe denominator of (j ω) should not be 0. To achieve said condition B, G is definedc(j ω) is in the range [0 °, 180 °]In the range according to FiExpression of(s), FiThe phase angle of (j ω) can be expressed as:
Figure BDA0002502692750000085
wherein the content of the first and second substances,
Figure BDA0002502692750000086
is Fi(j ω) phase angle of denominator polynomial, FiThe denominator of (j ω) is expressed as 1+ Di(j ω) wherein Di(j ω) is represented by:
Figure BDA0002502692750000087
then D isiThe phase angle of (j ω) is expressed as:
Figure BDA0002502692750000091
according to the stable conditions
Figure BDA0002502692750000092
DiThe (j ω) phase angle ranges from 90 to 180, and, in addition, according to the principle of vector summation,
Figure BDA0002502692750000093
is in the range of [0 DEG ] and angle Di(jω)]. Due to the fact that
Figure BDA0002502692750000094
Then there is
Figure BDA0002502692750000095
Therefore, to make < Fi(j omega) is less than or equal to 180 DEG, should be controlled
Figure BDA0002502692750000096
And due to
Figure BDA0002502692750000097
Then there is
Figure BDA0002502692750000098
Therefore, to make < Fi(j omega) is not less than 0 DEG, should be made
Figure BDA0002502692750000099
Thus, satisfy
Figure BDA00025026927500000910
When it is, F can be madeiThe phase angle of (j omega) is limited to [0 DEG, 180 DEG ]]Within the range. According to the principle of vector sum, 1 +. SIGMA FiPhase angle of (j ω)
Figure BDA00025026927500000911
At [0 °, 180 °)]Within the range. And F is only when ω is 0i(j ω) 180 °. At this time, 1 +. SIGMA Fi(j ω) is the smallest real number, if 1 +. sigma.Fi(j ω) is greater than 0, i.e. Gc(jω))|ω＝0>0, then GcThe denominator of (j ω) is always not 0, Gc(s) has no pole on the imaginary axis of the s-plane. Fig. 3 is a simplified circuit diagram and a norton equivalent circuit diagram when ω is 0, where when ω is 0, the reactance and the capacity in the system circuit are both 0, and the circuit includes only the power supply side resistor RsLoad side line stray resistance RLiAnd negative resistance-RiDue to the presence of RLi<RiThen the resistance R of each branchoi＝RLi-RiAre all negative, so the total parallel load resistance R∑And must also be negative. Gc(j ω) can be expressed as:
Figure BDA00025026927500000912
wherein R is∑For all CPL loads connected in parallel to the bus, R∑//RsRepresenting the total load of the system Noton equivalent model to satisfy Gc(jω)|ω＝0>0, should be such that R∑//Rs>0. Due to the existence of RLi<RiThus R∑<0, therefore it is necessary to make Rs<|R∑L to make Gc(jω)|ω＝0>0. Thus, the stable condition 2 is
Figure BDA00025026927500000913
And R iss<|R∑|。
In step S33, transfer function G is performed according to the bus voltage of the distributed dc power gridc(s) condition C, that the denominator and the numerator of the transfer function are in the same order, is satisfied, and the stability condition 3 of the distributed direct current power grid is determined to be unlimited. According to GcThe high frequency part of the(s) curve is
Figure BDA0002502692750000101
Available GcThe denominator and the numerator of(s) are of the same order, so there is no limitation on stable condition 3.
In step S34, transfer function G of dc voltage of distributed dc power grid is usedc(s) satisfies the condition D,
Figure BDA0002502692750000102
The stability condition 4 of the distributed dc grid is determined to be unlimited.
According to GcExpression of(s), GcThe(s) curve ends at (1, j0) and lies on the true axis, thus, to meet the system stability requirement, GcPhase angle of(s)
Figure BDA0002502692750000103
Should always not be equal to ± 180 °. According to the above analysis, 1 +. SIGMA FiThe phase angle of (j omega) ranges from 0 DEG to 180 DEG, then
Figure BDA0002502692750000104
Is in the range of [ -180 °, 0 °]In addition, due to GcDenominator 1 +. sigma.F of (j ω)i(j ω) is the smallest real number when ω is 0 and is greater than 0, and therefore
Figure BDA0002502692750000105
Gc(j ω) has no intersection with the negative semi-real axis and the system is stable, so there is no limit to stable condition 4.
In step S35, the stable condition 1, the stable condition 2, the stable condition 3, and the stable condition 4 are integrated, and it is determined that the integrated stable condition of the distributed dc power grid is
Figure BDA0002502692750000106
In step S36, the stability of the distributed dc power grid is analyzed according to the comprehensive stability condition of the distributed dc power grid. The stability condition 1 ensures the stability of the capacitor voltage of each CPL front end, and on the basis, the stability conditions 2, 3 and 4 ensure the stability of the direct current bus voltage, so that according to the comprehensive stability condition, when all values of the distributed direct current power grid meet the comprehensive stability condition, the overall stability of the system can be ensured. For example, in practical design, inductive reactance and accommodation in a circuit can be directly ignored, a Noton equivalent model of a system is established, and according to Rs<|R∑Directly obtaining the power supply side resistance R under the condition of |sThe upper limit range of (1).
Example 2
The system is used for operating the method suitable for analyzing the stability of the distributed direct current power grid and analyzing the stability of the distributed direct current power grid. It should be understood that all or part of the steps of the method for the distributed dc power grid stability analysis may be implemented by instructing related hardware to complete through a computer program, which may be stored in a non-volatile computer-readable storage medium, and when executed, may implement all or part of the steps of the method as described above. If the comprehensive judgment condition is stored in the nonvolatile computer readable storage medium, after the structure of a certain distributed direct current power grid is input, the system automatically establishes a mathematical model for the distributed direct current power grid, and judges the value range of one or more components according to the comprehensive stability condition so as to keep the distributed direct current power grid stable.
It should be noted that the above embodiments are only used for illustrating the technical solution of the present invention, and not for limiting the same; although the foregoing embodiments illustrate the invention in detail, those skilled in the art will appreciate that: it is possible to modify the technical solutions described in the foregoing embodiments or to substitute some or all of the technical features thereof, without departing from the scope of the technical solutions of the present invention.

Claims (2)

1. A method suitable for distributed direct current power grid stability analysis comprises the following steps:
establishing a mathematical model of a distributed direct-current power grid and a transfer function of bus voltage of the distributed direct-current power grid;
based on the Nyquist theorem, a system stability judgment method is provided;
according to the system stability judgment method, a transfer function of the bus voltage of the distributed direct-current power grid is analyzed, and a stable condition is determined, wherein the method is characterized in that:
the mathematical model of the distributed direct current power grid is as follows: the impedance Zs at the power supply side is equivalent to a resistor RsAnd an inductance LsThe load front-end filter is equivalent to a resistor RLiInductor LiAnd a capacitor CiThe constant power load CPL is equivalent to a negative resistance-RiThe transfer function of the bus voltage of the distributed direct-current power grid is as follows:
Figure FDA0003454586150000011
wherein U isdcFor bus voltage, UsIs the supply voltage, Y∑For the total load admittance in parallel on the bus,
Figure FDA0003454586150000012
n is the number of CPL connected in parallel on the bus, i is 1, 2, …, n;
based on the Nyquist theorem, the method for judging the system stability comprises the following steps:
establishing a complex domain model of the system, and using a system closed-loop transfer function G1c(s) defining the input-output relationship of the system, wherein
Figure FDA0003454586150000013
Wherein z is1，z2，…，zmRepresents G1cM zeros, λ, of(s)1，λ2，…，λnRepresents G1cN poles of(s);
setting the system closed loop transfer function G1c(s) satisfies the preconditions: A. all zeros are positioned on the left half plane of the s plane, B has no pole on the virtual axis of the s plane, and C, the denominator and the numerator of the transfer function are of the same order;
determining the stable conditions D of the system according to the Nyquist contour mapping theorem,
Figure FDA0003454586150000014
Wherein
Figure FDA0003454586150000015
Represents G1cPhase angle of(s), M represents G1c(s) an end point of the curve, M being greater than 0 indicates that the end point is located on the positive real axis, and M being less than 0 indicates that the end point M is located on the negative real axis;
according to the system stability judgment method, the transfer function of the bus voltage of the distributed direct-current power grid is analyzed, and the stable condition is determined, wherein the method comprises the following steps:
according to the transfer function G of the distributed DC networkc(s) determining a stable condition 1 of the distributed direct current power grid when the condition A is required to be met and all zero points are located on the left half plane of the s plane, wherein the stable condition 1 is
Figure FDA0003454586150000021
According to the pointTransfer function G of distributed direct-current power gridc(s) determining a stable condition 2 of the distributed direct current power grid when the condition B is satisfied and no pole exists on the imaginary axis of the s plane, wherein the stable condition 2 is
Figure FDA0003454586150000022
And R iss<|R∑Wherein R is∑The CPL load total resistance value of all the CPL loads connected to the bus in parallel;
according to the transfer function G of the distributed DC networkc(s) determining a stable condition 3 of the distributed direct current power grid when the condition C, the denominator and the numerator of the transfer function are in the same order, wherein the stable condition 3 is unlimited;
according to the transfer function G of the distributed DC networkc(s) satisfies the condition D,
Figure FDA0003454586150000023
Determining a stable condition 4 of the distributed direct current power grid, wherein the stable condition 4 is unlimited;
synthesizing the stable condition 1, the stable condition 2, the stable condition 3 and the stable condition 4 to determine the comprehensive stable condition of the distributed direct current power grid, wherein the comprehensive stable condition is
Figure FDA0003454586150000024
And analyzing the stability of the distributed direct current power grid according to the comprehensive stability condition of the distributed direct current power grid.
2. The utility model provides a system suitable for distributed DC electric wire netting stability analysis which characterized in that: for operating the method for analyzing the stability of a distributed dc power grid according to claim 1, the stability of the distributed dc power grid is analyzed.
CN202010437133.0A 2020-05-21 2020-05-21 Method and system suitable for distributed direct-current power grid stability analysis Active CN111654016B (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
CN202010437133.0A CN111654016B (en) 2020-05-21 2020-05-21 Method and system suitable for distributed direct-current power grid stability analysis

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
CN202010437133.0A CN111654016B (en) 2020-05-21 2020-05-21 Method and system suitable for distributed direct-current power grid stability analysis

Publications (2)

Publication Number Publication Date
CN111654016A CN111654016A (en) 2020-09-11
CN111654016B true CN111654016B (en) 2022-03-15

Family

ID=72348310

Family Applications (1)

Application Number Title Priority Date Filing Date
CN202010437133.0A Active CN111654016B (en) 2020-05-21 2020-05-21 Method and system suitable for distributed direct-current power grid stability analysis

Country Status (1)

Country Link
CN (1) CN111654016B (en)

Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US9136773B2 (en) * 2011-09-09 2015-09-15 Virginia Tech Intellectual Properties, Inc. Method of evaluating and ensuring stability of AC/DC power systems
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
CN109327043A (en) * 2018-10-24 2019-02-12 中国电力科学研究院有限公司 A kind of voltage source converter grid-connected system inner loop control parsing transfer function modeling method and system
CN110011295A (en) * 2019-03-06 2019-07-12 中国电力科学研究院有限公司 A kind of method for analyzing stability and system of distributed DC power grid

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US9136773B2 (en) * 2011-09-09 2015-09-15 Virginia Tech Intellectual Properties, Inc. Method of evaluating and ensuring stability of AC/DC power systems
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
CN109327043A (en) * 2018-10-24 2019-02-12 中国电力科学研究院有限公司 A kind of voltage source converter grid-connected system inner loop control parsing transfer function modeling method and system
CN110011295A (en) * 2019-03-06 2019-07-12 中国电力科学研究院有限公司 A kind of method for analyzing stability and system of distributed DC power grid

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
交直流微电网中变换器级联系统稳定性分析与协同控制;黄旭程等;《中国电机工程学报》;20190305;第39卷(第5期);全文 *

Also Published As

Publication number Publication date
CN111654016A (en) 2020-09-11

Similar Documents

Publication Publication Date Title
CN108649780B (en) LCL filter parameter optimization method considering inverter stability under weak grid
CN113054640B (en) Direct current converter parallel system stability criterion method based on impedance decomposition
CN111740575A (en) Inverter model parameter self-adaptive identification method based on steepest descent method
CN109861226B (en) LCL filter design method for comprehensively optimizing harmonic stability and damping loss
CN111654016B (en) Method and system suitable for distributed direct-current power grid stability analysis
CN107623341B (en) VSC inverter station mathematical model for supplying power to passive network and internal model controller
CN112597736B (en) Method for analyzing high-frequency oscillation stability of direct-current micro-grid
CN109672212B (en) LCL grid-connected inverter current inner loop full-order sliding mode virtual control method
CN108322050A (en) A kind of topological optimization suitable for resonant network and component parameters optimization method
WO2023236624A1 (en) Control method and apparatus for parallel apf
CN110912110B (en) Dynamic self-adaptive droop control method for direct-current micro-grid
CN109165474B (en) Inverter repetitive control design method based on neural network
CN110460054B (en) Design method for controller parameters and feedback damping coefficients of digital control system of three-phase current source grid-connected inverter
CN110134004B (en) PI control parameter setting method based on power spring circuit structure
Zhou et al. Model predictive control with fractional-order delay compensation for fast sampling systems
CN112865521B (en) Active damping control method and system for constant-power load system of Buck converter
CN113489357B (en) Microgrid inverter control method and system, storage medium and computing equipment
Almakhles et al. Single-bit modulator based controller for capacitive power transfer system
CN111668826B (en) Stability analysis method and system for direct-current power supply system of pure electric vehicle
CN114899875A (en) Network-building grid-connected inverter
CN110165677B (en) Voltage stable control method for single-phase alternating-current power spring
CN112018768B (en) Method and device for analyzing harmonic transfer characteristics of multi-terminal flexible direct-current power transmission system
CN110768234B (en) Peak filtering method for direct-current micro-grid system with uncertainty feed constant-power load
CN106598911B (en) A kind of column write method of circuit network state equation
Abderrahmane et al. Non linear control of the UPQC for grid current and voltage improvement

Legal Events

Date Code Title Description
PB01 Publication
PB01 Publication
SE01 Entry into force of request for substantive examination
SE01 Entry into force of request for substantive examination
GR01 Patent grant
GR01 Patent grant