High-proportion new energy power grid strength evaluation method and system

Abstract

The invention provides a high-proportion new energy power grid strength evaluation method and system. The method comprises the following steps: constructing a full-system dynamic matrix model comprising all power supplies and network elements of a system according to system parameters; solving an admittance sensitivity factor of the to-be-studied characteristic value for the admittance of the specified equipment according to the full-system dynamic matrix; according to the admittance sensitivity factor, calculating the admittance stability capacity of the specified equipment; and determining a power grid strength improvement scheme according to the admittance stable capacity. Therefore, by establishing a system small signal model in a complex frequency domain and defining and calculating the admittance stability capacity of the power grid strength index, the interaction of all dynamic elements of the multi-machine system is effectively reflected, the influence of converter control parameters on the system stability is successfully captured, and the small signal stability of the system is described from a local perspective; and the power grid strength quantitative evaluation method based on the admittance stable capacity is obtained.

Description

Technical Field

[0001] The present application relates to the field of power grid analysis and management, and in particular to a method and system for evaluating the strength of a power grid with a high proportion of renewable energy. Background Art

[0002] With the high proportion of new energy connected to the power system, a large number of power electronic devices are pouring into the power grid. The small signal stability problem caused by the dynamic interaction between different devices is a complex problem under wide bandwidth. In order to improve the strength of the power grid, people usually want to know the local strength of the power grid and clarify which parameters need to be improved. Most existing studies use short-circuit ratio to describe the strength of the power grid from a static and global perspective. The short-circuit ratio of new energy multi-stations takes into account the interaction between different stations and can evaluate the strength of the power grid when a large number of power electronic devices are connected to the grid, but it can only be used to analyze the static voltage stability at the base frequency. The generalized short-circuit ratio defined as the minimum eigenvalue of the system characteristic equation can describe the small signal stability of the system, but the minimum eigenvalue is a global indicator that describes the strength of the power grid, which is not intuitive enough when analyzing the local strength of the system. Although many short-circuit ratio indicators that can describe the strength of the power grid and the small signal stability of the system have been proposed, there is currently a lack of a method to establish the relationship between specific equipment and the small signal stability of the system, and to achieve an accurate description of the local small signal stability of the system. Summary of the invention

[0003] The purpose of this application is to provide a method and system for evaluating the strength of a high-proportion renewable energy grid, to establish a grid strength index that describes the small-signal stability of the system from a local perspective, to propose a grid strength index based on the admittance sensitivity factor, to accurately describe the dynamic characteristics of the entire system, and to describe the small-signal stability of the system from the perspective of specific equipment.

[0004] To achieve the above-mentioned purpose, the high-proportion new energy grid strength assessment method provided in the present application specifically includes: constructing a full-system dynamic matrix model including all power sources and network elements of the system based on system parameters; solving the admittance sensitivity factor of the eigenvalue to be studied for the admittance of the specified device based on the full-system dynamic matrix; calculating the admittance stability capacity of the specified device based on the admittance sensitivity factor; and determining the grid strength improvement plan based on the admittance stability capacity.

[0005] In the above-mentioned high-proportion renewable energy grid strength assessment method, optionally, constructing a full-system dynamic matrix model including all power sources and network elements of the system according to system parameters includes: constructing a small-signal model of the power system by impedance modeling of the power source and the power network in the complex frequency domain according to the system parameters; and obtaining a full-system dynamic matrix model by aligning the small-signal models of the power system of each power source through coordinate system.

[0006] In the above-mentioned high-proportion new energy grid strength assessment method, optionally, solving the admittance sensitivity factor of the eigenvalue to be studied for the admittance of a specified device based on the dynamic matrix of the entire system includes: constructing an admittance sensitivity matrix for the specified device through the eigenvalue to be studied; and obtaining the admittance sensitivity factor of the eigenvalue to be studied for the admittance of the specified device based on the admittance sensitivity matrix and the dynamic matrix of the entire system.

[0007] In the above-mentioned high-proportion new energy grid strength assessment method, optionally, calculating the admittance stability capacity of a specified device based on the admittance sensitivity factor includes: calculating the eigenvalue change of the eigenvalue to be studied based on the admittance sensitivity factor; obtaining the admittance sensitivity of the eigenvalue to be studied to the specified device based on the eigenvalue change analysis, and calculating the admittance stability capacity of the specified device based on the admittance sensitivity of the system eigenvalue to the specified device.

[0008] In the above-mentioned high-proportion new energy grid strength assessment method, optionally, determining a grid strength improvement plan based on the admittance stability capacity includes: characterizing the degree of influence of the admittance change of a designated device on the characteristic value to be studied based on the admittance stability capacity to locate the target power source that affects the system stability; and prompting the grid strength by adjusting the device parameters of the designated device based on the target power source.

[0009] The present application also provides a high-proportion new energy power grid strength assessment system, which includes: a construction module, which is used to construct a full-system dynamic matrix model including all power supplies and network elements of the system according to system parameters; an analysis module, which is used to solve the admittance sensitivity factor of the eigenvalue to be studied for the admittance of a specified device according to the full-system dynamic matrix; a calculation module, which is used to calculate the admittance stability capacity of the specified device according to the admittance sensitivity factor; and a processing module, which is used to determine a power grid strength improvement plan based on the admittance stability capacity.

[0010] In the above-mentioned high-proportion new energy grid strength assessment system, optionally, the construction module includes a generation unit and an alignment unit; the generation unit is used to perform impedance modeling on the power supply and the power network respectively in the complex frequency domain according to the system parameters to construct a small signal model of the power system; the alignment unit is used to obtain a dynamic matrix model of the entire system by aligning the coordinate system according to the small signal model of the power system of each power supply.

[0011] In the above-mentioned high-proportion new energy grid strength assessment system, optionally, the analysis module includes: constructing an admittance sensitivity matrix for a specified device through the eigenvalue to be studied; and obtaining the admittance sensitivity factor of the eigenvalue to be studied for the admittance of the specified device based on the admittance sensitivity matrix and the full system dynamic matrix analysis.

[0012] In the above-mentioned high-proportion new energy grid strength assessment system, optionally, the calculation module includes: calculating the characteristic value change of the characteristic value to be studied according to the admittance sensitivity factor; obtaining the admittance sensitivity of the characteristic value to be studied to the specified device according to the characteristic value change analysis, and calculating the admittance stability capacity of the specified device according to the admittance sensitivity of the system characteristic value to the specified device.

[0013] In the above-mentioned high-proportion new energy grid strength assessment system, optionally, the processing module includes a positioning unit and an adjustment unit; the positioning unit is used to locate the target power source that affects the system stability according to the degree of influence of the admittance change of the designated device on the characteristic value to be studied according to the admittance stability capacity characterization; the adjustment unit is used to prompt the grid strength by adjusting the device parameters of the designated device according to the target power source.

[0014] The present application also provides an electronic device, comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor implements the above method when executing the computer program.

[0015] The present application also provides a computer-readable storage medium, wherein the computer-readable storage medium stores a computer program for executing the above method.

[0016] The present application also provides a computer program product, comprising a computer program / instruction, which implements the steps of the above method when executed by a processor.

[0017] The beneficial technical effect of the present application is that by establishing a system small signal model in the complex frequency domain, defining and calculating the admittance stability capacity of the grid strength indicator, the interaction of all dynamic elements of the multi-machine system is effectively reflected, the influence of the converter control parameters on the system stability is successfully captured, and the small signal stability of the system is described from a local perspective, thereby obtaining a quantitative evaluation method of the grid strength based on the admittance stability capacity. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] The drawings described herein are used to provide a further understanding of the present application, constitute a part of the present application, and do not constitute a limitation of the present application. In the drawings:

[0019] Figure 1A A schematic diagram of a flow chart of a method for evaluating the strength of a high-proportion new energy grid provided in an embodiment of the present application;

[0020] Figure 1B A schematic diagram of system impedance modeling provided in an embodiment of the present application;

[0021] Figure 2 A schematic diagram of a process for obtaining a dynamic matrix model of the entire system provided in an embodiment of the present application;

[0022] Figure 3 A schematic diagram of a flow chart for obtaining an admittance sensitivity factor provided in an embodiment of the present application;

[0023] Figure 4A A schematic diagram of a flow chart of the calculation of the admittance stability capacity provided in one embodiment of the present application;

[0024] Figure 4B A schematic diagram of a flow chart for determining a plan for improving the strength of a power grid provided in an embodiment of the present application;

[0025] Figure 5 Schematic diagram of the pole diagram and the impedance element spectrum of the whole system under different cases of a single-grid type converter connected to an infinite system provided by an embodiment of the present application;

[0026] Figure 6 A schematic diagram of response waveforms of a single-grid type converter connected to an infinite system in different cases when the active load at the PCC point increases by 0.1 pu according to an embodiment of the present application;

[0027] Figure 7 Schematic diagram of the pole diagram and the impedance element spectrum of the whole system under different cases of a single grid-type converter connected to an infinite system provided by an embodiment of the present application;

[0028] Figure 8 A schematic diagram of response waveforms of a single grid-type converter connected to an infinite system in different cases when the active load at the PCC point increases by 0.1 pu according to an embodiment of the present application;

[0029] Fig. 9 A schematic diagram of the spectrum of the pole diagram and the impedance element of the whole system under different cases of the modified 14-bus system provided in one embodiment of the present application;

[0030] Fig.10 A schematic diagram of a response waveform of a 0.1 pu increase in active load at the PCC point of GFM3 under different cases of a 14-bus system transformation provided in an embodiment of the present application;

[0031] Fig.11 A schematic diagram of a response waveform of an increase of 0.1 pu in active load at the PCC point of GFL2 under different cases of a 14-bus system transformation provided in an embodiment of the present application;

[0032] Fig.12 A schematic diagram of the structure of a modified busbar system 14 provided in an embodiment of the present application;

[0033] Fig.13 A schematic diagram of the principle structure of a high-proportion new energy grid strength assessment system provided in one embodiment of the present application;

[0034] Fig.14A schematic diagram of the structure of an electronic device provided in one embodiment of the present application. DETAILED DESCRIPTION

[0035] The following will describe the implementation methods of the present application in detail in conjunction with the accompanying drawings and embodiments, so that the implementation process of how the present application applies technical means to solve technical problems and achieve technical effects can be fully understood and implemented accordingly. It should be noted that as long as there is no conflict, the various embodiments in the present application and the various features in the embodiments can be combined with each other, and the technical solutions formed are all within the protection scope of the present application.

[0036] In addition, the steps shown in the flowcharts of the accompanying drawings can be executed in a computer system such as a set of computer-executable instructions, and although a logical order is shown in the flowcharts, in some cases, the steps shown or described can be performed in an order different from that shown here.

[0037] Please refer to Figure 1A As shown, the high-proportion new energy grid strength assessment method provided in this application specifically includes:

[0038] S101 builds a full system dynamic matrix model including all power and network components of the system based on system parameters;

[0039] S102 solves the admittance sensitivity factor of the characteristic value to be studied to the admittance of the specified device according to the dynamic matrix of the whole system;

[0040] S103 calculates the admittance stability capacity of the specified device according to the admittance sensitivity factor;

[0041] S104 determines a plan to improve the strength of the power grid according to the admittance stability capacity.

[0042] Specifically, in actual work, the purpose of the high-proportion new energy grid strength assessment method provided in this application is to propose a grid strength index based on the admittance sensitivity factor, accurately describe the dynamic characteristics of the whole system, and describe the small signal stability of the system from the perspective of specific equipment. During implementation, it mainly includes establishing a full-system dynamic matrix model containing all power supplies and network elements of the system, solving the admittance sensitivity factor of the eigenvalue to be studied for the admittance of the specified device according to the full-system dynamic matrix, calculating the admittance stability capacity of the specified device according to the admittance sensitivity factor, and determining the grid strength improvement plan according to the admittance stability capacity. The specific implementation logic of each step will be described in detail in subsequent embodiments, so it will not be described in detail here.

[0043] In the above step S101, the dynamic matrix model of the whole system is mainly composed of the small signal model of the power system. Therefore, it is necessary to perform impedance modeling on the power source and the power network in the complex frequency domain respectively to establish the small signal model of the power system; please refer to Figure 2As shown, in one embodiment of the present application, constructing a full system dynamic matrix model including all power supplies and network elements of the system according to system parameters includes:

[0044] S201 performs impedance modeling on the power supply and the power network in the complex frequency domain according to the system parameters to construct a small signal model of the power system;

[0045] S202 obtains a dynamic matrix model of the entire system by aligning coordinate systems based on the power system small signal models of each power source.

[0046] Specifically, in the admittance modeling step of the dynamic elements of the whole system, the system impedance modeling block diagram can be referred to Figure 1B As shown, the small signal impedance / admittance model of the power supply can be obtained through theoretical deduction or actual measurement, namely:

[0047]

[0048] where Y Gi and Z Gi They represent the admittance and impedance of the power source connected to busbar i, respectively. and are the corresponding elements of the dq rotating coordinate system. If there is no power supply at bus i, there is Y Gi =0.

[0049] It should be noted that the small signal model of each power supply in the multi-machine system is established in its own reference coordinate system, so it is necessary to align the coordinate system through methods such as dynamic embedding. The power supply admittance matrix Y of the system can be obtained from each power supply admittance model. G :

[0050]

[0051] where Y G ∈2n×2n represents the admittance matrix of the system power supply, and n is the number of system nodes.

[0052] Small signal model Y of power network N It is the node admittance matrix established in the complex frequency domain dq coordinate system:

[0053]

[0054] where Y Nij represents the mutual admittance element between buses i and j, Y Nii represents the self-admittance element of bus i.

[0055] Consider the perturbation value of the injected current at each bus of the network as input:

[0056] Δu=ΔI=[ΔI1…ΔI i …ΔIn ] T ; (4)

[0057] Where ΔI i is the injected current disturbance value of bus i, which has two components, dq, namely ΔI i =[ΔI id ,ΔI iq ] T , T represents matrix transpose, and n is the number of busbars.

[0058] The voltage change at each bus is output as:

[0059] Δy=ΔU=[ΔU1…ΔU i …ΔU n ] T ; (5)

[0060] Similarly, ΔU i =[ΔU id ,ΔU iq ] T .

[0061] When there is an injected current disturbance at the bus, there is a shunt between the power supply and the power network. The voltage change at the bus can be calculated from the power supply current change and the power supply admittance matrix. The voltage change at the bus and the injected current of the power network are constrained by the power network node admittance matrix. Therefore, the relationship between the injected current and voltage change of the bus can be established:

[0062]

[0063] E is the unit matrix, Z is the dynamic matrix of the whole system that reflects the response transfer function of the injected disturbance to the bus. In the context of this paper where the input is current disturbance and the output is voltage disturbance, it exhibits impedance matrix characteristics. Y is the inverse matrix of the Z matrix, which is called the admittance matrix of the whole system.

[0064] Since the small signal model of the power supply and power network is established in the complex frequency domain, the dynamic matrix of the whole system can reflect the dynamic characteristics of the system, and the dynamic matrices Z and Y of the whole system satisfy that the values ​​of their determinants at the characteristic roots are 0.

[0065] In the process of constructing the eigenvalue admittance sensitivity in step S102, the admittance sensitivity factor of the specified device admittance is calculated mainly based on the dynamic matrix of the whole system. Please refer to Figure 3 As shown, in one embodiment of the present application, solving the admittance sensitivity factor of the characteristic value to be studied for the admittance of the specified device according to the dynamic matrix of the whole system includes:

[0066] S301 constructs an admittance sensitivity matrix for a specified device through the eigenvalues ​​to be studied;

[0067] S302: Obtaining the admittance sensitivity factor of the characteristic value to be studied with respect to the admittance of a specified device according to the admittance sensitivity matrix and the whole system dynamic matrix analysis.

[0068] In actual work, the system eigenvalue can be set to the specific device admittance sensitivity matrix S λ , and have:

[0069]

[0070] where Y ki That is, the element in the kth row and ith column of the admittance matrix of the entire system. It should be noted that it is a second-order matrix.

[0071] Expand the determinant of the admittance matrix of the whole system row by row:

[0072]

[0073] Where det is the operation to find the matrix determinant, C ki Y ki The corresponding algebraic cofactors are:

[0074]

[0075] If a small disturbance occurs in the system power supply parameters, the eigenvalue and the power supply admittance value at the new stable operating point will change, and at the new operating point, the determinant of the admittance matrix of the entire system at the eigenvalue is 0, that is:

[0076]

[0077] Among them, the subscript "0" means that it is the parameter before the disturbance. The Taylor expansion of the whole system admittance matrix after the disturbance is used at the eigenvalue λ, ignoring the second-order and higher-order terms and substituting them into equation (10) is:

[0078]

[0079] Therefore, the sensitivity matrix element expression can be obtained:

[0080]

[0081] The sensitivity matrix is:

[0082]

[0083] The residue of the impedance matrix of the whole system at the eigenvalue λ satisfies:

[0084]

[0085] Where Res represents the residue operation. Combining equations (13) and (14), we have:

[0086] Res λ Z=-S λ ; (15)

[0087] Therefore, the sensitivity of the eigenvalue to the device admittance is:

[0088]

[0089] Where tr() means taking the trace of the matrix as a whole with dq components, γ dd , γ dq , γ qd and γ qq Respectively represent the components of the sensitivity dq axis. Expanding equation (16) yields:

[0090]

[0091] The admittance sensitivity factor of the element is defined as:

[0092]

[0093] Where * indicates taking the matrix conjugate transpose. So the eigenvalue change can be expressed by the admittance sensitivity factor and the device admittance change, that is:

[0094] Δλ= λ,y ,Δy>; (19)

[0095] Where <,> represents the Frobenius inner product.

[0096] In the process of calculating the admittance stability capacity in step S103, the admittance stability capacity is mainly determined by sensitivity analysis. Please refer to Figure 4A As shown, in one embodiment of the present application, calculating the admittance stability capacity of a specified device according to the admittance sensitivity factor includes:

[0097] S401 calculates the characteristic value change amount of the characteristic value to be studied according to the admittance sensitivity factor;

[0098] S402 obtains the admittance sensitivity of the characteristic value to be studied to the designated device according to the characteristic value change analysis, and calculates the admittance stability capacity of the designated device according to the admittance sensitivity of the system characteristic value to the designated device.

[0099] In actual work, the purpose of this example is to calculate the stable capacity of the power grid strength index admittance. It can be considered that a small disturbance ΔY appears in the power admittance at bus j kj , then the eigenvalue λ to be investigated i Admittance Y to power supply j kj ​The sensitivity of is given by formula (17):

[0100]

[0101] Therefore, the relationship between the change in eigenvalue and the change in admittance of power source j can be calculated:

[0102]

[0103] The condition for the system to remain stable is that the eigenvalue has a negative real part, so the eigenvalue λ i The maximum allowable change is its distance from the imaginary axis, that is:

[0104] |Δλ i | max =|σ i |; (22)

[0105] where σ i is the eigenvalue λ i Real part, substitute equation (22) into equation (21) and combine with the inequality to scale it up:

[0106]

[0107] where || F represents the Frobenius norm.

[0108] Therefore, it can be known that the admittance Y of power supply j under the condition of system stability kj The maximum change should satisfy:

[0109]

[0110] Since the maximum value of the admittance change required by equation (24) is for the eigenvalue λ i In actual evaluation of system strength, it is necessary to satisfy that all eigenvalues ​​have negative real parts, that is, for each eigenvalue there is a maximum power supply admittance change max{|ΔY Gj (λ i )| F Correspondingly, the Admittance Stability Capacity (ASC) can be defined as the minimum value of the maximum admittance change corresponding to different eigenvalues, that is:

[0111]

[0112] in Denotes the eigenvalue λ i Find the minimum value of the expression over all eigenvalues ​​λ.

[0113] In the process of improving the grid strength in the above step S104, the grid strength of the system is mainly improved based on the admittance stability capacity. Please refer to Figure 4B As shown, in one embodiment of the present application, determining a grid strength improvement scheme according to the admittance stability capacity includes:

[0114] S501 locates the target power source that affects the stability of the system according to the admittance stability capacity characterizing the influence of the admittance change of the designated device on the characteristic value to be studied;

[0115] S502 prompts the grid strength by adjusting the device parameters of the designated device according to the target power source.

[0116] In actual work, ASC is used to characterize the influence of the change of specific device admittance on the system eigenvalue, locate the key power source that affects the stability of the system, and accurately improve the strength of the power grid by adjusting the parameters of the device. ASC originates from the dynamic matrix of the whole system. The network topology relationship and the device control parameters are respectively reflected in the node admittance matrix and the power admittance matrix that constitute the dynamic matrix of the whole system. Therefore, ASC can reflect the interaction of all dynamic elements of the multi-machine system and can capture the influence of the converter control parameters on the stability of the system. ASC characterizes the influence of the change of specific device admittance on the system eigenvalue. It describes the small signal stability of the system from a local perspective. The value of ASC represents the tolerance of the system eigenvalue to the change of specific device admittance. A large ASC value indicates that the admittance of the device is allowed to change greatly under the premise of system stability, and the system is less sensitive to the change of the admittance of the device, that is, the anti-interference ability is strong, and the local stability margin of the power supply is large, that is, the strength of the power grid is high; a small ASC value indicates that the system allows the power supply to change less when maintaining stability, the system is more sensitive to the power supply, and the local power grid strength is low. Therefore, the key power supply that affects the stability of the system can be located by ASC, and the strength of the power grid can be accurately improved by adjusting the parameters of the device.

[0117] In order to facilitate a clearer understanding of the specific application method of the high-proportion new energy grid strength assessment method provided in this application, the above-mentioned assessment method is illustrated by a specific example below. Relevant technical personnel in this field should know that this example does not impose any limitation on the technical solution claimed to be protected by this application.

[0118] The following three sets of simulations verify the practicality of the ASC index, including 8 cases in total, cases 1-3 of a single grid-type converter connected to an infinite system (corresponding to Figure 5 , Figure 6 , Table 1) and single grid type converter connected to infinite system case 4-6 (corresponding to Figure 7 , Figure 8 ) illustrates the effectiveness of ASC indicators for different types of converters, and the case 7-8 (corresponding to Fig. 9 , Fig.10 , Fig.11 ) illustrates the applicability of the indicator to larger-scale power systems.

[0119] First is Figure 5 The single grid-type converter connected to infinity system shown in the upper middle part (a), where the grid impedance is 0.02+0.1ip.u., adjust the voltage loop bandwidth and droop gain of the grid-type converter, and the specific parameters are shown in Table 1. From the results of Table 1 (parameter settings and ASC values ​​of the single grid-type converter connected to infinity system), it can be judged that the order of grid strength is: Case 3>Case 1>Case 2. The time domain simulation results are shown in Figure 5 (b)(c) and Figure 6 As shown, Figure 5 (b) shows the distribution of system eigenvalues ​​under different parameter conditions. It can be seen that the dominant pole of Case 3 is farthest from the imaginary axis, followed by Case 1, and the dominant pole of Case 2 is closest to the imaginary axis, which means that the system stability margin is Case 3>Case 1>Case 2, which is consistent with the ASC judgment result. Figure 5 (c) shows the spectrum of the impedance element of the whole system under different parameters. The peak of the spectrum represents the existence of an oscillation mode in the system at this frequency, and the peak value represents the distance of the mode relative to the imaginary axis. The larger the peak value, the closer it is to the imaginary axis. Therefore, it can be seen that the stability margin situation is still case 3> case 1> case 2. When a small disturbance occurs, the time domain changes of the electrical quantities in different cases are as follows: Figure 6 As shown, it can be seen that when the same disturbance occurs, Case 2 takes the longest time to recover stability, and Case 3 takes the shortest time, which means that Case 3 has the best stability, Case 1 is second, and Case 2 is the worst, which fully demonstrates the effectiveness of the ASC indicator in evaluating the strength of the power grid in the grid-connected scenario of the grid-connected converter.

[0120] Table 1

[0121]

[0122] Similarly, for Figure 7 For the single grid-type converter connected to infinity system shown in (a), the current loop bandwidth, phase-locked loop bandwidth and DC voltage loop bandwidth configurations of different grid-type converters are shown in Table 2 (parameter settings and ASC values ​​of single grid-type converter connected to infinity system). The stability results judged by the ASC index are Case 4>Case 5>Case 6, and Figure 7 The pole distribution diagram in (b) Figure 7 The impedance element spectrum diagram in (c) and Fig.14 The waveform diagrams of the electrical quantity response after the disturbance all show that the system stability is Case 4>Case 5>Case 6, indicating that the ASC index is also applicable to the grid-connected scenario of the grid-following converter.

[0123] Table 2

[0124]

[0125] like Fig.12 The 14-bus system shown in the transformation is a grid-following converter connected to buses 1, 2 and 6, while the converter connected to buses 3 and 8 is a grid-forming converter. The droop gain of GFM3 and the current loop bandwidth, phase-locked loop bandwidth and DC voltage loop bandwidth of GFL2 are adjusted, and two different control parameter combinations are considered as shown in Table 3 (parameter settings and ASC values ​​of the 14-bus system transformation). Fig. 9 The system pole diagram in (a) shows that Case 7 has multiple poles very close to the imaginary axis, which is reflected in Fig. 9 There are corresponding peaks in the spectrograms of (b) and (c), indicating that GFM3 and GFML2 have poor stability and are prone to large amplitude oscillations. Fig. 9 It can be seen that the impedance element spectrum peak corresponding to Case 8 is smaller, so the stability is better. Fig.10 and Fig.11 The time domain waveform change curves of the electrical quantities of GFM3 and GFL2 after the disturbance are given respectively. It is obvious that the electrical quantities of the system in Case 8 recover stability faster, that is, the stability is better. The ASC results in Table 3 also show that the stability judgment result is Case 8> Case 7, which means that ASC is suitable for larger-scale systems.

[0126] Table 3

[0127]

[0128] Please refer to Fig.13 As shown, the present application also provides a high-proportion new energy power grid strength assessment system, the system comprising: a construction module, used to construct a full-system dynamic matrix model including all power supplies and network elements of the system according to system parameters; an analysis module, used to solve the admittance sensitivity factor of the eigenvalue to be studied for the admittance of a specified device according to the full-system dynamic matrix; a calculation module, used to calculate the admittance stability capacity of the specified device according to the admittance sensitivity factor; a processing module, used to determine a power grid strength improvement plan based on the admittance stability capacity.

[0129] In an embodiment, the construction module includes a generation unit and an alignment unit; the generation unit is used to perform impedance modeling on the power supply and the power network in the complex frequency domain according to the system parameters to construct a small signal model of the power system; the alignment unit is used to obtain a dynamic matrix model of the whole system by aligning the coordinate system according to the small signal model of the power system of each power supply. The analysis module includes: constructing an admittance sensitivity matrix for a specified device through the eigenvalue to be studied; and obtaining the admittance sensitivity factor of the eigenvalue to be studied for the admittance of the specified device according to the admittance sensitivity matrix and the full system dynamic matrix analysis.

[0130] In another embodiment of the present application, the calculation module includes: calculating the characteristic value change amount of the characteristic value to be studied according to the admittance sensitivity factor; analyzing the characteristic value change amount to obtain the admittance sensitivity of the characteristic value to be studied to the designated device, and calculating the admittance stability capacity of the designated device according to the admittance sensitivity of the system characteristic value to the designated device. The processing module includes a positioning unit and an adjustment unit; the positioning unit is used to locate the target power source that affects the stability of the system according to the admittance stability capacity to characterize the influence of the admittance change of the designated device on the characteristic value to be studied; the adjustment unit is used to prompt the grid strength by adjusting the device parameters of the designated device according to the target power source.

[0131] Since the principle of solving the problem by this system is similar to the method for evaluating the strength of a high-proportion renewable energy power grid, the implementation of this system can refer to the implementation of the method for evaluating the strength of a high-proportion renewable energy power grid, and the repeated parts will not be repeated.

[0132] The beneficial technical effect of the present application is that: based on the admittance sensitivity factor analysis of the dynamic matrix of the entire system, a numerical relationship between the change in admittance of a specific device and the change in the system eigenvalue is established. On this basis, the admittance stability capacity quantifies the maximum allowable change in admittance under the premise of maintaining system stability, effectively solving the problem of small signal stability judgment considering the dynamic characteristics of all power supplies and networks in a multi-machine system, and is a quantitative indicator of power grid strength at the device level.

[0133] The present application also provides an electronic device, comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor implements the above method when executing the computer program.

[0134] The present application also provides a computer-readable storage medium, wherein the computer-readable storage medium stores a computer program for executing the above method.

[0135] The present application also provides a computer program product, comprising a computer program / instruction, which implements the steps of the above method when executed by a processor.

[0136] like Fig.14 As shown, the electronic device 600 may further include: a communication module 110, an input unit 120, an audio processor 130, a display 160, and a power supply 170. It is worth noting that the electronic device 600 does not necessarily have to include Fig.14 In addition, the electronic device 600 may also include Fig.14 For components not shown, reference may be made to the prior art.

[0137] like Fig.14As shown, the central processor 100 is sometimes also referred to as a controller or an operation control, and may include a microprocessor or other processor devices and / or logic devices. The central processor 100 receives inputs and controls the operations of various components of the electronic device 600.

[0138] The memory 140 may be, for example, one or more of a cache, a flash memory, a hard drive, a removable medium, a volatile memory, a non-volatile memory or other suitable devices. The above-mentioned information related to the failure may be stored, and a program for executing the relevant information may also be stored. The CPU 100 may execute the program stored in the memory 140 to implement information storage or processing.

[0139] The input unit 120 provides input to the CPU 100. The input unit 120 is, for example, a key or a touch input device. The power supply 170 is used to provide power to the electronic device 600. The display 160 is used to display display objects such as images and text. The display may be, for example, an LCD display, but is not limited thereto.

[0140] The memory 140 may be a solid-state memory, such as a read-only memory (ROM), a random access memory (RAM), a SIM card, etc. It may also be a memory that saves information even when the power is off, can be selectively erased, and is provided with more data, examples of which are sometimes referred to as EPROMs, etc. The memory 140 may also be some other type of device. The memory 140 includes a buffer memory 141 (sometimes referred to as a buffer). The memory 140 may include an application / function storage unit 142, which is used to store application programs and function programs or processes for executing the operation of the electronic device 600 through the central processor 100.

[0141] The memory 140 may also include a data storage unit (data 143) for storing data, such as contacts, digital data, pictures, sounds, and / or any other data used by the electronic device. The driver storage unit (driver 144) of the memory 140 may include various drivers for communication functions of the electronic device and / or for executing other functions of the electronic device (such as messaging applications, address book applications, etc.).

[0142] The communication module 110 is a transmitter / receiver 110 that transmits and receives signals via an antenna 111. The communication module (transmitter / receiver) 110 is coupled to the central processor 100 to provide input signals and receive output signals, which may be the same as the case of a conventional mobile communication terminal.

[0143] Based on different communication technologies, multiple communication modules 110 may be provided in the same electronic device, such as a cellular network module, a Bluetooth module and / or a wireless LAN module. The communication module (transmitter / receiver) 110 is also coupled to a speaker 131 and a microphone 132 via an audio processor 130 to provide an audio output via the speaker 131 and receive an audio input from the microphone 132, thereby realizing a common telecommunication function. The audio processor 130 may include any suitable buffer, decoder, amplifier, etc. In addition, the audio processor 130 is also coupled to the central processor 100, so that the sound can be recorded on the local machine through the microphone 132, and the sound stored on the local machine can be played through the speaker 131.

[0144] Those skilled in the art will appreciate that the embodiments of the present application may be provided as methods, systems, or computer program products. Therefore, the present application may adopt the form of a complete hardware embodiment, a complete software embodiment, or an embodiment in combination with software and hardware. Moreover, the present application may adopt the form of a computer program product implemented in one or more computer-usable storage media (including but not limited to disk storage, CD-ROM, optical storage, etc.) that include computer-usable program code.

[0145] The present application is described with reference to the flowchart and / or block diagram of the method, device (system) and computer program product according to the embodiment of the present application. It should be understood that each process and / or box in the flowchart and / or block diagram, and the combination of the process and / or box in the flowchart and / or block diagram can be realized by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, a special-purpose computer, an embedded processor or other programmable data processing device to produce a machine, so that the instructions executed by the processor of the computer or other programmable data processing device produce a device for realizing the function specified in one process or multiple processes in the flowchart and / or one box or multiple boxes in the block diagram.

[0146] These computer program instructions may also be stored in a computer-readable memory that can direct a computer or other programmable data processing device to work in a specific manner, so that the instructions stored in the computer-readable memory produce a manufactured product including an instruction device that implements the functions specified in one or more processes in the flowchart and / or one or more boxes in the block diagram.

[0147] These computer program instructions may also be loaded onto a computer or other programmable data processing device so that a series of operational steps are executed on the computer or other programmable device to produce a computer-implemented process, whereby the instructions executed on the computer or other programmable device provide steps for implementing the functions specified in one or more processes in the flowchart and / or one or more boxes in the block diagram.

[0148] The specific embodiments described above further illustrate the purpose, technical solutions and beneficial effects of the present application. It should be understood that the above description is only a specific embodiment of the present application and is not intended to limit the scope of protection of the present application. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present application should be included in the scope of protection of the present application.

Claims

1. A method for evaluating the strength of a high-proportion renewable energy grid, characterized in that: The method comprises: Construct a full system dynamic matrix model including all power and network components of the system according to system parameters; Solve the admittance sensitivity factor of the eigenvalue to be studied for the specified device admittance according to the dynamic matrix of the whole system; Calculate the admittance stability capacity of a specified device based on the admittance sensitivity factor; Determine the plan to improve the grid strength based on the admittance stability capacity.

2. The method for evaluating the strength of a high-proportion renewable energy grid according to claim 1, characterized in that: The dynamic matrix model of the whole system including all power and network components of the system is constructed according to the system parameters, including: According to the system parameters, the impedance modeling of the power supply and the power network is carried out in the complex frequency domain to construct a small signal model of the power system; The dynamic matrix model of the whole system is obtained by aligning the coordinate system according to the small signal model of the power system of each power source.

3. The method for evaluating the strength of a high-proportion new energy grid according to claim 1 is characterized in that: Solving the admittance sensitivity factor of the eigenvalue to be studied for the specified device admittance based on the dynamic matrix of the whole system includes: Construct the admittance sensitivity matrix for the specified device through the eigenvalues ​​to be studied; The admittance sensitivity factor of the characteristic value to be studied with respect to the admittance of a specified device is obtained according to the admittance sensitivity matrix and the full system dynamic matrix analysis.

4. The method for evaluating the strength of a high-proportion renewable energy grid according to claim 1, characterized in that: Calculation of the admittance stability capacity of a specified device based on the admittance sensitivity factor includes: The eigenvalue change amount of the eigenvalue to be studied is obtained by calculating the admittance sensitivity factor; The admittance sensitivity of the characteristic value to be studied to the designated device is obtained according to the characteristic value change analysis, and the admittance stability capacity of the designated device is calculated according to the admittance sensitivity of the system characteristic value to the designated device.

5. The method for evaluating the strength of a high-proportion new energy grid according to claim 1, characterized in that: The grid strength improvement plan determined based on the admittance stability capacity includes: Characterize the influence of the admittance change of the specified equipment on the characteristic value to be studied according to the admittance stability capacity and locate the target power source that affects the stability of the system; The grid strength is indicated by adjusting device parameters of the designated device according to the target power supply.

6. A high-proportion new energy grid strength assessment system, characterized in that: The system comprises: A building module, used for building a full system dynamic matrix model including all power and network elements of the system according to system parameters; An analysis module is used to solve the admittance sensitivity factor of the characteristic value to be studied to the admittance of the specified device according to the dynamic matrix of the whole system; A calculation module, used for calculating the admittance stability capacity of a specified device according to the admittance sensitivity factor; The processing module is used to determine a plan to improve the strength of the power grid according to the admittance stability capacity.

7. The high-proportion new energy grid strength assessment system according to claim 6 is characterized in that: The building module comprises a generation unit and an alignment unit; The generating unit is used to perform impedance modeling on the power supply and the power network in the complex frequency domain according to the system parameters to construct a small signal model of the power system; The alignment unit is used to obtain a dynamic matrix model of the entire system through coordinate system alignment according to the power system small signal model of each power supply.

8. The high-proportion new energy grid strength assessment system according to claim 6 is characterized in that: The analysis module comprises: constructing an admittance sensitivity matrix for a specified device through the eigenvalue to be studied; and obtaining an admittance sensitivity factor of the eigenvalue to be studied for the admittance of the specified device according to the admittance sensitivity matrix and the full system dynamic matrix analysis.

9. The high-proportion new energy grid strength assessment system according to claim 6 is characterized in that: The calculation module includes: calculating the characteristic value change of the characteristic value to be studied according to the admittance sensitivity factor; obtaining the admittance sensitivity of the characteristic value to be studied to the specified device according to the characteristic value change analysis, and calculating the admittance stability capacity of the specified device according to the admittance sensitivity of the system characteristic value to the specified device.

10. The high-proportion new energy grid strength assessment system according to claim 6, characterized in that: The processing module includes a positioning unit and an adjustment unit; The positioning unit is used to locate the target power source that affects the stability of the system according to the admittance stability capacity characterizing the influence of the admittance change of the designated device on the characteristic value to be studied; The adjustment unit is used to prompt the grid strength by adjusting the device parameters of the designated device according to the target power source.

11. An electronic device comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, characterized in that: When the processor executes the computer program, the method according to any one of claims 1 to 5 is implemented.

12. A computer-readable storage medium, characterized in that: The computer-readable storage medium stores a computer program, and when the computer program is executed by a processor, the method according to any one of claims 1 to 5 is implemented.

13. A computer program product comprising a computer program / instructions, characterized in that When the computer program / instructions are executed by a processor, the steps of the method according to any one of claims 1 to 5 are implemented.

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