A method, system, apparatus and medium for identifying inter-unit swing and instability

Abstract

The application discloses a kind of identification method, system, device and medium of swing and instability between generating units, belong to electric power technical field.The method includes the following steps: obtaining generator power angle curve after time domain simulation;According to the obtained generator power angle curve, obtain accelerating instability machine group and the instability time of each unit;According to accelerating instability machine group and instability time, obtain the relative swing index of each generator, to realize the identification of swing and instability between generating units.The application obtains the dynamic information of generator according to time domain simulation, identifies accelerating instability machine group and the instability time of each unit therein, calculates the relative swing index suitable for stable, instability unit, can provide accurate instability machine group and its control priority for transient stability prevention control of dispatching operation.

Description

Technical Field

[0001] This invention relates to the field of power technology, and in particular to a method, system, device, and medium for identifying swaying and instability between generating units. Background Technology

[0002] As traditional power systems transform and upgrade to new types of power systems, transient stability assessment is becoming increasingly important for early warning of power grid security and stability risks. Currently, most research focuses on system-level transient stability, proposing a series of stability categories and stability level indicators to indicate the distance between the current operating point and boundaries, and potential exceedances. However, power grid operators are more concerned with the stability indicators of fine-grained, controllable components. The relative sway between generators determines the direction of transient stability development after a fault, indicating differences in generator instability modes, and has significant reference value for generator grouping and adjustment sequence in preventative control. How to programmatically generate generator relative sway indicators based on power angle curves from a large-scale sample is a key technical problem that urgently needs to be solved to improve dispatching efficiency. Summary of the Invention

[0003] In order to at least partially solve one of the technical problems existing in the prior art, the present invention aims to provide a method, system, device and medium for identifying sway and instability between units.

[0004] The technical solution adopted in this invention is:

[0005] A method for identifying inter-unit swaying and instability includes the following steps:

[0006] Obtain the generator power angle curve after time-domain simulation;

[0007] Based on the obtained generator power angle curves, the instability time of the accelerated instability group and each unit is obtained;

[0008] Based on the accelerated instability group and instability time, the relative sway index of each generator is obtained to identify sway and instability between units.

[0009] Furthermore, the step of obtaining the instability time of the accelerated instability group and each unit based on the obtained generator power angle curve includes:

[0010] Define the generator sequence number set G, and the power angle curve δ of each generator. i (t), i∈G, and the absolute value of the maximum power angle difference between any two generators i and j at time t, |Δδ(t)|. G :

[0011] |Δδ(t)| G =max i,j |δ i (t)-δj (t)|,i,j∈G (1)

[0012] And the generator pair corresponding to the maximum power angle difference:

[0013] {i max i min} t,G =arg max i,j |δ i (t)-δ j (t)|,i,j∈G (2)

[0014] For formula (2), we have

[0015] Accelerated Instability Cluster G u and the set of instability times T u The search process is as follows:

[0016] 1) Determine the initial set of unstable mechanisms Set of instability times The smallest step Δt of the simulation curve, the absolute value of the critical work angle difference |Δδ(t)| c And the maximum simulation duration T;

[0017] 2) Calculate |Δδ(t)| according to formulas (1) and (2). G and {i max i min} t,G ;

[0018] 3) If |Δδ(t)| G ≥|Δδ(t)| c Then i max Add to accelerated instability cluster G u Corresponding time Then store it in the set of instability times T. u Remove i from the generator sequence number set G max If the length |G| of the generator sequence set G is greater than 1, then let t = t + Δt; otherwise, directly output the accelerating unstable generator group G. u and the set of instability times T u End the process; if |Δδ(t)| G <|Δδ(t)| c Then let t = t + Δt;

[0019] 4) If t≤T, repeat steps 2) to 3); if t>T, end the process and output the accelerated instability cluster G. u and the set of instability times T u The stable cluster is G s The stable cluster Gs Remove the set of accelerated unstable clusters G from set G. u The group after.

[0020] Furthermore, the step of obtaining the relative sway index of each generator based on the accelerated instability group and the instability time includes:

[0021] For a stable generator i∈G, the peak value of the relative power angle difference Δδ r,i,max Defined as:

[0022] Δδ r,i,max =max t (δ i (t)-θ ref (t)) (3)

[0023] In the formula, θ ref (t) is the reference curve;

[0024] Combined with accelerated instability group G u and the set of instability times T u ={t u,i The relative sway index γ of the i-th generator G,i The definition is as follows:

[0025]

[0026] In the formula, C δ,max t′ is a constant; u,i =(t u,i -μ u ) / ξ u μ is the normalized value of the instability time. u ξ u Each of the t samples in the historical samples u,i The mean and variance of τ; τ is the modulation parameter; σ(·) is the sigmoid function; ε is the preset threshold.

[0027] Furthermore, the voltage phase angle curve of core substations with an outage probability below a threshold is obtained as a reference curve θ. ref (t).

[0028] Another technical solution adopted in this invention is:

[0029] An inter-unit sway and instability identification system, comprising:

[0030] The parameter acquisition module is used to acquire the generator power angle curve after time-domain simulation.

[0031] The instability search module is used to obtain the instability time of the accelerated instability group and each unit based on the obtained generator power angle curve;

[0032] The index calculation module is used to obtain the relative sway index of each generator based on the accelerated instability group and the instability time, so as to identify the sway and instability between units.

[0033] Furthermore, the step of obtaining the instability time of the accelerated instability group and each unit based on the obtained generator power angle curve includes:

[0034] Define the generator sequence number set G, and the power angle curve δ of each generator. i (t), i∈G, and the absolute value of the maximum power angle difference between any two generators i and j at time t, |Δδ(t)|. G :

[0035] |Δδ(t)| G =max i,j |δ i (t)-δ j (t)|,i,j∈G (5)

[0036] And the generator pair corresponding to the maximum power angle difference:

[0037] {i max i min} t,G =arg max i,j |δ i (t)-δ j (t)|,i,j∈G (6)

[0038] For formula (6), we have

[0039] Accelerated Instability Cluster G u and the set of instability times T u The search process is as follows:

[0040] 1) Determine the initial set of unstable mechanisms Set of instability times The smallest step Δt of the simulation curve, the absolute value of the critical work angle difference |Δδ(t)| c And the maximum simulation duration T;

[0041] 2) Calculate |Δδ(t)| according to formulas (5) and (6). G and {i max i min} t,G ;

[0042] 3) If |Δδ(t)| G ≥|Δδ(t)| c Then i max Add to accelerated instability cluster G u Corresponding time Then store it in the set of instability times T. u Remove i from the generator sequence number set G max If the length |G| of the generator sequence set G is greater than 1, then let t = t + Δt; otherwise, directly output the accelerating unstable generator group G. u and the set of instability times T u End the process; if |Δδ(t)| G <|Δδ(t)| c Then let t = t + Δt;

[0043] 4) If t≤T, repeat steps 2) to 3); if t>T, end the process and output the accelerated instability cluster G. u and the set of instability times T u The stable cluster is G s The stable cluster G s Remove the set of accelerated unstable clusters G from set G. u The group after.

[0044] Furthermore, the step of obtaining the relative sway index of each generator based on the accelerated instability group and the instability time includes:

[0045] For a stable generator i∈G, the peak value of the relative power angle difference Δδ r,i,max Defined as:

[0046] Δδ r,i,max =max t (δ i (t)-θ ref (t)) (7)

[0047] In the formula, θ ref (t) is the reference curve;

[0048] Combined with accelerated instability group G u and the set of instability times T u ={t u,i The relative sway index γ of the i-th generator G,i The definition is as follows:

[0049]

[0050] In the formula, C δ,max t′ is a constant; u,i =(t u,i -μ u ) / ξ u μ is the normalized value of the instability time. u ξ u Each of the t samples in the historical samples u,i The mean and variance of τ; τ is the modulation parameter; σ(·) is the sigmoid function; ε is the preset threshold.

[0051] Furthermore, the voltage phase angle curve of core substations with an outage probability below a threshold is obtained as a reference curve θ. ref (t).

[0052] Another technical solution adopted in this invention is:

[0053] A device for identifying inter-unit swaying and instability, comprising:

[0054] At least one processor;

[0055] At least one memory for storing at least one program;

[0056] When the at least one program is executed by the at least one processor, the at least one processor performs the method as described above.

[0057] Another technical solution adopted in this invention is:

[0058] A computer-readable storage medium storing a processor-executable program, which, when executed by a processor, performs the method described above.

[0059] The beneficial effects of this invention are: based on the generator dynamic information obtained from time-domain simulation, this invention identifies the accelerated instability group and the instability time of each unit, calculates the relative sway index applicable to stable and unstable units, and can provide accurate unstable groups and their control priorities for transient stability prevention and control in scheduling operations. Attached Figure Description

[0060] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following description is provided with accompanying drawings of the relevant technical solutions in the embodiments of the present invention or the prior art. It should be understood that the accompanying drawings described below are only for the purpose of clearly illustrating some embodiments of the technical solutions of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0061] Figure 1 This is a flowchart illustrating the steps of a method for identifying inter-unit swaying and instability in an embodiment of the present invention.

[0062] Figure 2 This is a flowchart illustrating the calculation of the accelerated instability cluster and the instability time set in this embodiment of the invention.

[0063] Figure 3 This is a time-domain simulation curve after a fault in an embodiment of the present invention. Detailed Implementation

[0064] The embodiments of the present invention are described in detail below. Examples of these embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the present invention, and should not be construed as limiting the present invention. The step numbers in the following embodiments are set only for ease of explanation, and there is no limitation on the order between the steps. The execution order of each step in the embodiments can be adaptively adjusted according to the understanding of those skilled in the art.

[0065] In the description of this invention, it should be understood that the orientation descriptions, such as up, down, front, back, left, right, etc., are based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limiting this invention.

[0066] In the description of this invention, "several" means one or more, "more than" means two or more, "greater than," "less than," and "exceeding" are understood to exclude the stated number, while "above," "below," and "within" are understood to include the stated number. The use of "first" and "second" in the description is merely for distinguishing technical features and should not be construed as indicating or implying relative importance, or implicitly indicating the number of indicated technical features, or implicitly indicating the order of the indicated technical features.

[0067] Furthermore, in the description of this invention, unless otherwise stated, "multiple" means two or more. "And / or" describes the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A alone, A and B simultaneously, or B alone. The character " / " generally indicates that the preceding and following related objects have an "or" relationship.

[0068] In the description of this invention, unless otherwise explicitly defined, terms such as "set up," "install," and "connect" should be interpreted broadly, and those skilled in the art can reasonably determine the specific meaning of the above terms in this invention in conjunction with the specific content of the technical solution.

[0069] This invention designs a continuous index to describe transient sway and instability modes among generating units. First, based on generator dynamic information obtained from time-domain simulation, the accelerated instability group and the instability time of each unit within it are identified. Then, a relative sway index is defined that applies to both stable and unstable generating units. This method can provide accurate information on unstable generating groups and their control priorities for transient stability prevention and control in scheduled operations.

[0070] like Figure 1As shown, this embodiment provides a method for identifying inter-unit swaying and instability, including the following steps:

[0071] S1. Obtain the generator power angle curve after time-domain simulation.

[0072] S2. Based on the obtained generator power angle curve, obtain the instability time of the accelerated instability group and each unit.

[0073] The calculation process for the generator relative sway index consists of two main steps. First, it searches for the accelerated instability generator group and the set of instability times of the included instable generators. Step S2 specifically includes the following steps:

[0074] (1) Accelerated instability clusters and instability time sets

[0075] Define the generator sequence set Power angle curves δ of each generator i (t), i∈G, and the absolute value of the maximum power angle difference between any two generators i and j at time t, |Δδ(t)|. G :

[0076] |Δδ(t)| G =max i,j |δ i (t)-δ j (t)|,i,j∈G (1)

[0077] And the generator pair corresponding to the maximum power angle difference:

[0078] {i max i min} t,G =arg max i,j |δ i (t)-δ j (t)|,i,j∈G (2)

[0079] For equation (2), we have It should be noted that in equations (1) and (2), the absolute value of the maximum work angle difference |Δδ(t)| G The calculation is related to the set of generators corresponding to its subscript. Both generator indices i and j belong to the set of generator indices.

[0080] Based on this, the instability cluster G is accelerated. u and the set of instability times T u The search process is as follows Figure 2 As shown, the specific steps include:

[0081] 1) Given an initial set of leading unstable swarms Set of instability times The smallest step Δt of the simulation curve, the absolute value of the critical work angle difference |Δδ(t)| c (This value is a fixed value, and 180° is recommended) and the maximum simulation duration T.

[0082] 2) Calculate |Δδ(t)| according to equations (1) and (2). G and {i max i min} t,G .

[0083] 3) If |Δδ(t)| G ≥|Δδ(t)| c Then i max Add to accelerated instability cluster G u Corresponding time Then store it in the set of instability times T. u Remove i from G max If the length of G, |G|, is greater than 1, then let t = t + Δt; otherwise, output G directly. u T u The process ends if |Δδ(t)| G <|Δδ(t)| c Then let t = t + Δt.

[0084] 4) If t≤T, repeat steps 2) to 3). If t>T, end the process and output G. u and T u The stable cluster is G s The stable cluster G s Remove the set of accelerated unstable clusters G from set G. u The group after.

[0085] S3. Based on the accelerated instability group and instability time, obtain the relative sway index of each generator to identify sway and instability between units.

[0086] The voltage phase angle curve of the core substation with a low probability of outage is selected as the reference curve θ. ref (t). For a stable generator i∈G, the peak value of the relative power angle difference Δδ r,i,max Defined as:

[0087] Δδ r,i,max =max t (δ i (t)-θ ref (t)) (3)

[0088] Combined with G u and T u ={t u,i The relative sway index γ of the i-th generator G,iThe definition is as follows:

[0089]

[0090] In the formula, C δ,max Since it is a constant, it is recommended to take all Δδ from the historical samples. r,i,max The maximum value. Equation (4a) uses C δ,max For Δδ r,i.max Standardize it so that it lies between [ε, 1]. t′ u,i =(t u,i -μ u ) / ξ u μ is the normalized value of the instability time. u ξ u Each of the t samples in the historical samples u,i The mean and variance are given. The modulation parameter τ shifts minority values ​​to the saturation region of the sigmoid function σ(·). The threshold ε forms the uncertainty region [-ε, ε], used to capture units in critical states.

[0091] The above method will be explained in detail below with reference to the accompanying drawings and specific embodiments.

[0092] The test was conducted based on an IEEE 10-machine, 39-node system, which includes N... G =10 generators. Let the simulation duration T=4, and set the fault occurrence and clearing times to 0.2s and 0.3s respectively. Figure 3 A time-domain simulation case study is presented. It is clearly evident that generators 4-7 and generator 9 have lost synchronization with the rest of the generator group, representing an accelerated instability group in engineering terms. This invention elaborates on the calculation process of the relative sway index based on this case study.

[0093] (1) Calculation process of generator relative sway index

[0094] The minimum step size of the simulation curve is set to Δt = 0.01s, and the absolute value of the critical work angle difference is |Δδ(t)|. c =180° and the maximum simulation duration T=4s, initial G={1,2,3,4,5,6,7,8,9,10}. Table 1 shows the search process for the first unstable unit.

[0095] Table 1 Search Process for the First Instable Unit

[0096]

[0097]

[0098] As t is continuously increased, at t = 0.69s, we have |Δδ(t)| G >|Δδ(t| c. Record t u,9 = 0.69 s, {i max , i min} t,G = {9, 10}, at this time G u = {9}, T u = {0.69}, G = {1, 2, 3, 4, 5, 6, 7, 8, 10}. Since t < T and |G| > 1, continue to execute the search task. Table 2 shows the search process of the second unstable unit.

[0099] Table 2 Search Process of the Second Unstable Unit

[0100]

[0101]

[0102] Continuously increase t. When t = 1.23 s, |Δδ(t)| G >|Δδ(t)| c . Record t u,7 = 1.23 s, {i max , i min} t,G = {7, 10}, at this time G u = {9, 7}, T u = {0.69, 1.23}, G = {1, 2, 3, 4, 5, 6, 8, 10}. Since t < T and |G| > 1, continue to execute the search task. Table 3 shows the search process of the third unstable unit.

[0103] Table 3 Search Process of the Third Unstable Unit

[0104]

[0105] Continuously increase t. When t = 1.25 s, |Δδ(t)| G >|Δδ(t)| c . Record t u,6 = 1.25 s, {i max , i min} t,G = {6, 10}, at this time G u = {9, 7, 6}, T u = {0.69, 1.23, 1.25}, G = {1, 2, 3, 4, 5, 8, 10}. Since t < T and |G| > 1, continue to execute the search task. Table 4 shows the search process of the fourth unstable unit.

[0106] Table 4 Search Process of the Fourth Unstable Unit

[0107]

[0108] Continuously increase \(t\). When \(t = 1.69\ s\), there is \(|\Delta\delta(t)|\) G \(>|\Delta\delta(t)|\) c . Record \(t\) u,5 \(= 1.69\ s\), \(\{i\) max , \(i\) min}\) [[ID=~13]] t,G \(=\{5, 10\}\). At this time, \(G\) u \(=\{9, 7, 6, 5\}\), \(T\) u \(=\{0.69, 1.23, 1.25, 1.69\}\), \(G=\{1, 2, 3, 4, 8, 10\}\). Since \(t < T\) and \(|G|>1\), continue to execute the search task. Table 5 shows the search process of the 5th unstable unit.

[0109] Table 5 Search Process of the 5th Unstable Unit

[0110]

[0111]

[0112] Continuously increase \(t\). When \(t = 1.72\ s\), there is \(|\Delta\delta(t)|\) G \(>|\Delta\delta(t)|\) c . Record \(t\) u,4 \(= 1.72\ s\), \(\{i\) max , \(i\) min}\) <~ t,G \(=\{4, 10\}\). At this time, \(G\) u \(=\{9, 7, 6, 5, 4\}\), \(T\) u \(=\{0.69, 1.23, 1.25, 1.69, 1.72\}\), \(G=\{1, 2, 3, 8, 10\}\). Since \(t < T\) and \(|G|>1\), continue to execute the search task. Table 6 shows the subsequent search process.

[0113] Table 6 Subsequent Search Process

[0114]

[0115] Continuously increase \(t\). When \(t>4\ s\), there is no \(|\Delta\delta(t)|\) G \(>|\Delta\delta(t)|\) c , output \(G\) u \(=\{9, 7, 6, 5, 4\}\), \(T\) u \(=\{0.69, 1.23, 1.25, 1.69, 1.72\}\). From this, it can be known that the stable unit set is \(\{1, 2, 3, 8, 10\}\).

[0116] Based on 27793 historical samples, \(C\) can be calculated as δ,max \(= 190.685\), \(\mu\)u =1.311, ξ u =0.471, the reference curve is the voltage phase angle curve of bus No. 1. According to equation (3), Table 7 gives the calculated value of the peak relative power angle difference Δδ. r,i,max .

[0117] Table 7 Calculation value of peak relative power angle difference Δδ r,i,max

[0118] i 1 2 3 8 10 <![CDATA[Δδ r,i,max / ° ]]> 12.813 56.803 48.080 71.015 -0.819

[0119] Therefore, setting ε = 0.1 and τ = 1.5, according to equation (4), we obtain the relative sway indices of all generators as shown in Table 8. The smaller the relative sway index, the greater the generator's instability tendency or the severity of disturbance, and the more suitable it is as a control object.

[0120] Table 8 Calculation results of generator relative sway index

[0121] i 1 2 3 4 5 6 7 8 9 10 <![CDATA[γ G,i ]]> 0.974 0.641 0.697 -0.186 -0.191 -0.303 -0.310 0.557 -0.555 1

[0122] In summary, combining Figure 3 Simulation Case Study: Accelerated Instability Cluster G u The generator relative sway index can be accurately identified and effectively reflects the severity of the disturbance to the generator, making it easier for dispatchers to select appropriate generator sets for preventive control.

[0123] In summary, compared with the prior art, the present invention has at least the following advantages and beneficial effects: 1) it defines a search method for accelerated unstable generator groups and a method for marking the instability time of unstable generator groups; 2) it defines a stability index for a single continuous generator and describes the relative sway of stable and unstable generator groups.

[0124] This embodiment also provides a system for identifying inter-unit swaying and instability, including:

[0125] The parameter acquisition module is used to acquire the generator power angle curve after time-domain simulation.

[0126] The instability search module is used to obtain the instability time of the accelerated instability group and each unit based on the obtained generator power angle curve;

[0127] The index calculation module is used to obtain the relative sway index of each generator based on the accelerated instability group and the instability time, so as to identify the sway and instability between units.

[0128] As a further optional implementation, the step of obtaining the instability time of the accelerated instability group and each unit based on the obtained generator power angle curve includes:

[0129] Define the generator sequence number set G, and the power angle curve δ of each generator. i (t), i∈G, and the absolute value of the maximum power angle difference between any two generators i and j at time t, |Δδ(t)|. G :

[0130] |Δδ(t)| G =max i,j |δ i (t)-δ j (t)|,i,j∈G (5)

[0131] And the generator pair corresponding to the maximum power angle difference:

[0132] {i max i min} t,G =arg max i,j |δ i (t)-δ j (t)|,i,j∈G (6)

[0133] For formula (6), we have

[0134] Accelerated Instability Cluster G u and the set of instability times T u The search process is as follows:

[0135] 1) Determine the initial set of unstable mechanisms Set of instability times The smallest step Δt of the simulation curve, the absolute value of the critical work angle difference |Δδ(t)| c And the maximum simulation duration T;

[0136] 2) Calculate |Δδ(t)| according to formulas (5) and (6). G and {i max i min} t,G ;

[0137] 3) If |Δδ(t)| G ≥|Δδ(t)| c Then i max Add to accelerated instability cluster G u Corresponding time Then store it in the set of instability times T. u Remove i from the generator sequence number set G max If the length |G| of the generator sequence set G is greater than 1, then let t = t + Δt; otherwise, directly output the accelerating unstable generator group G. u and the set of instability times T u End the process; if |Δδ(t)|G <|Δδ(t)| c Then let t = t + Δt;

[0138] 4) If t≤T, repeat steps 2) to 3); if t>T, end the process and output the accelerated instability cluster G. u and the set of instability times T u The stable cluster is G s The stable cluster G s Remove the set of accelerated unstable machine clusters G from set G. u The group after.

[0139] As a further optional implementation, obtaining the relative sway index of each generator based on the accelerated instability cluster and instability time includes:

[0140] For a stable generator i∈G, the peak value of the relative power angle difference Δδ r,i,max Defined as:

[0141] Δδ r,i,max =max t (δ i (t)-θ ref (t)) (7)

[0142] In the formula, θ ref (t) is the reference curve;

[0143] Combined with accelerated instability group G u and the set of instability times T u ={t u,i The relative sway index γ of the i-th generator G,i The definition is as follows:

[0144]

[0145] In the formula, C δ,max t′ is a constant; u,i =(t u,i -μ u ) / ξ u μ is the normalized value of the instability time. u ξ u Each of the t samples in the historical samples u,i The mean and variance of τ; τ is the modulation parameter; σ(·) is the sigmoid function; ε is the preset threshold.

[0146] As a further optional implementation, the voltage phase angle curve of the core substation with an outage probability below a threshold is obtained as a reference curve θ. ref (t).

[0147] This embodiment of the system for identifying inter-unit swaying and instability can execute the inter-unit swaying and instability identification method provided in the method embodiment of the present invention, and can execute any combination of the implementation steps of the method embodiment, possessing the corresponding functions and beneficial effects of the method.

[0148] This embodiment also provides a device for identifying inter-unit swaying and instability, including:

[0149] At least one processor;

[0150] At least one memory for storing at least one program;

[0151] When the at least one program is executed by the at least one processor, the at least one processor performs the following: Figure 1 The method shown.

[0152] This embodiment provides a device for identifying inter-unit swaying and instability, which can execute the inter-unit swaying and instability identification method provided in the method embodiment of the present invention. It can execute any combination of the implementation steps of the method embodiment and has the corresponding functions and beneficial effects of the method.

[0153] This application also discloses a computer program product or computer program, which includes computer instructions stored in a computer-readable storage medium. A processor of a computer device can read the computer instructions from the computer-readable storage medium and execute the computer instructions, causing the computer device to perform... Figure 1 The method shown.

[0154] This embodiment also provides a storage medium storing instructions or programs that can execute the method for identifying inter-unit sway and instability provided in the method embodiment of the present invention. When the instructions or programs are run, any combination of implementation steps of the method embodiment can be executed, and the method has the corresponding functions and beneficial effects.

[0155] In some alternative embodiments, the functions / operations mentioned in the block diagrams may not occur in the order shown in the operation diagrams. For example, depending on the functions / operations involved, two consecutively shown blocks may actually be executed substantially simultaneously, or the blocks may sometimes be executed in reverse order. Furthermore, the embodiments presented and described in the flowcharts of this invention are provided by way of example to provide a more comprehensive understanding of the technology. The disclosed methods are not limited to the operations and logic flows presented herein. Alternative embodiments are contemplated in which the order of various operations is altered and sub-operations described as part of a larger operation are executed independently.

[0156] Furthermore, although the invention has been described in the context of functional modules, it should be understood that, unless otherwise stated, one or more of the described functions and / or features may be integrated into a single physical device and / or software module, or one or more functions and / or features may be implemented in a separate physical device or software module. It is also understood that a detailed discussion of the actual implementation of each module is unnecessary for understanding the invention. Rather, given the properties, functions, and internal relationships of the various functional modules in the apparatus disclosed herein, the actual implementation of the module will be understood within the scope of conventional skill of an engineer. Therefore, those skilled in the art can implement the invention as set forth in the claims using ordinary techniques without excessive experimentation. It is also understood that the specific concepts disclosed are merely illustrative and not intended to limit the scope of the invention, which is determined by the full scope of the appended claims and their equivalents.

[0157] If the aforementioned functions are implemented as software functional units and sold or used as independent products, they can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of this invention, essentially, or the part that contributes to the prior art, or a portion of the technical solution, can be embodied in the form of a software product. This computer software product is stored in a storage medium and includes several instructions to cause a computer device (which may be a personal computer, server, or network device, etc.) to execute all or part of the steps of the methods described in the various embodiments of this invention. The aforementioned storage medium includes various media capable of storing program code, such as USB flash drives, portable hard drives, read-only memory (ROM), random access memory (RAM), magnetic disks, or optical disks.

[0158] The logic and / or steps represented in the flowchart or otherwise described herein, for example, can be considered as a sequenced list of executable instructions for implementing logical functions, and can be embodied in any computer-readable medium for use by, or in conjunction with, an instruction execution system, apparatus, or device (such as a computer-based system, a processor-included system, or other system that can fetch and execute instructions from, an instruction execution system, apparatus, or device). For the purposes of this specification, "computer-readable medium" can be any means that can contain, store, communicate, propagate, or transmit programs for use by, or in conjunction with, an instruction execution system, apparatus, or device.

[0159] More specific examples of computer-readable media (a non-exhaustive list) include: electrical connections (electronic devices) having one or more wires, portable computer disk drives (magnetic devices), random access memory (RAM), read-only memory (ROM), erasable and editable read-only memory (EPROM or flash memory), fiber optic devices, and portable optical disc read-only memory (CDROM). Furthermore, computer-readable media can even be paper or other suitable media on which the program can be printed, since the program can be obtained electronically, for example, by optically scanning the paper or other medium, followed by editing, interpreting, or otherwise processing as necessary, and then stored in computer memory.

[0160] It should be understood that various parts of the present invention can be implemented in hardware, software, firmware, or a combination thereof. In the above embodiments, multiple steps or methods can be implemented in software or firmware stored in memory and executed by a suitable instruction execution system. For example, if implemented in hardware, as in another embodiment, it can be implemented using any one or a combination of the following techniques known in the art: discrete logic circuits having logic gates for implementing logical functions on data signals, application-specific integrated circuits (ASICs) having suitable combinational logic gates, programmable gate arrays (PGAs), field-programmable gate arrays (FPGAs), etc.

[0161] In the foregoing description of this specification, references to terms such as "one embodiment," "another embodiment," or "some embodiments" indicate that a specific feature, structure, material, or characteristic described in connection with an embodiment or example is included in at least one embodiment or example of the present invention. In this specification, illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0162] Although embodiments of the invention have been shown and described, those skilled in the art will understand that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the claims and their equivalents.

[0163] The above is a detailed description of the preferred embodiments of the present invention. However, the present invention is not limited to the above embodiments. Those skilled in the art can make various equivalent modifications or substitutions without departing from the spirit of the present invention. All such equivalent modifications or substitutions are included within the scope defined by the claims of this application.

Claims

1. A method for identifying inter-unit swaying and instability, characterized in that, Includes the following steps: Obtain the generator power angle curve after time-domain simulation; Based on the obtained generator power angle curves, the instability time of the accelerated instability group and each unit is obtained; Based on the accelerated instability group and instability time, the relative sway index of each generator is obtained to identify sway and instability between units. The step of obtaining the instability time of the accelerated instability group and each unit based on the obtained generator power angle curve includes: Define the generator sequence set Power angle curves of each generator as well as t Any two generators at any time i , j The absolute value of the maximum work angle difference between : （1） And the generator pair corresponding to the maximum power angle difference: （2） For formula (2), we have ; Accelerated Instability Cluster and instability time set The search process is as follows: 1) Determine the initial set of unstable mechanisms Instability time set The smallest step of the simulation curve absolute value of critical work angle difference and maximum simulation duration ; 2) Calculated according to formulas (1) and (2) and ; 3) If Then Add to accelerated instability cluster Corresponding time Then store in the set of instability times From the generator serial number set Delete If the generator sequence number set length If it is greater than 1, then let Conversely, directly outputting accelerated instability of the machine group and instability time set End the process; if Then let ; 4) If Repeat steps 2) to 3); if End the process and output the accelerated instability cluster. and instability time set Stable clusters are ; The process of obtaining the relative sway index of each generator based on the accelerated instability group and instability time includes: For stable generators Peak relative power angle difference Defined as: （3） In the formula, For reference curve; Combined with accelerated instability cluster and instability time set , No. i Relative sway index of generator The definition is as follows: （4） In the formula, It is a constant; This is the normalized value of the instability time. , All of the historical samples The mean and variance; These are modulation parameters; It is the sigmoid function; This is a preset threshold.

2. The method for identifying inter-unit swaying and instability according to claim 1, characterized in that, The voltage phase angle curve of core substations with an outage probability below a threshold is obtained as a reference curve. .

3. A system for identifying swaying and instability between generating units, characterized in that, include: The parameter acquisition module is used to acquire the generator power angle curve after time-domain simulation. The instability search module is used to obtain the instability time of the accelerated instability group and each unit based on the obtained generator power angle curve; The index calculation module is used to obtain the relative sway index of each generator based on the accelerated instability group and the instability time, so as to identify the sway and instability between units. The step of obtaining the instability time of the accelerated instability group and each unit based on the obtained generator power angle curve includes: Define the generator sequence set Power angle curves of each generator as well as t Any two generators at any time i , j The absolute value of the maximum work angle difference between : （5） And the generator pair corresponding to the maximum power angle difference: （6） For formula (6), we have ; Accelerated Instability Cluster and instability time set The search process is as follows: 1) Determine the initial set of unstable mechanisms Instability time set The smallest step of the simulation curve absolute value of critical work angle difference and maximum simulation duration ; 2) Calculated according to formulas (5) and (6) and ; 3) If Then Add to accelerated instability cluster Corresponding time Then store in the set of instability times From the generator serial number set Delete If the generator sequence number set length If it is greater than 1, then let Conversely, directly outputting accelerated instability of the machine group and instability time set End the process; if Then let ; 4) If Repeat steps 2) to 3); if End the process and output the accelerated instability cluster. and instability time set Stable clusters are ; The process of obtaining the relative sway index of each generator based on the accelerated instability group and instability time includes: For stable generators Peak relative power angle difference Defined as: （7） In the formula, For reference curve; Combined with accelerated instability cluster and instability time set , No. i Relative sway index of generator The definition is as follows: （8） In the formula, It is a constant; This is the normalized value of the instability time. , All of the historical samples The mean and variance; These are modulation parameters; It is the sigmoid function; This is a preset threshold.

4. The inter-unit swaying and instability identification system according to claim 3, characterized in that, The voltage phase angle curve of core substations with an outage probability below a threshold is obtained as a reference curve. .

5. A device for identifying swaying and instability between generating units, characterized in that, include: At least one processor; At least one memory for storing at least one program; When the at least one program is executed by the at least one processor, the at least one processor performs the method of claim 1 or 2.

6. A computer-readable storage medium storing a processor-executable program, characterized in that, The processor-executable program is used to perform the method as described in claim 1 or 2 when executed by the processor.

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