A PSD-BPA data preprocessing method for electromagnetic transient modeling

Abstract

The present application relates to a kind of PSD-BPA data preprocessing methods for electromagnetic transient modeling, belong to technical field, comprising: (1) according to BPA data card type identification electrical equipment type;(2) remove small reactance branch, to reduce branch and node;(3) identification transformer model of the same substation, judge equivalent merging condition, to reduce the modeling scale of substation;(4) identification generator model, booster transformer of the same power plant, judge equivalent merging condition, equivalent generator node, relevant control model and booster transformer.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of power system simulation, and particularly relates to a PSD-BPA data preprocessing method for electromagnetic transient modeling. BACKGROUND

[0002] With the development of power systems, modern power systems gradually form a huge interconnected mode to improve power quality and power supply reliability. How to ensure the safe and stable operation of large systems is a major and urgent problem. On the one hand, large-scale power systems contain a large number of generators, buses, lines, transformers and other devices and elements, and detailed system models are composed of algebraic equations describing the network and differential equations describing the dynamic of generators. From the perspective of calculation amount and calculation time, it is difficult to conduct stability analysis on large-scale systems through detailed modeling. On the other hand, when analyzing the real-time simulation or dynamic modeling experiment of interconnected systems, the software resources (RTDS, EMTDC, EMTP, etc.) or the time-consuming detailed solution are often limited. In actual engineering, the electromechanical simulation data of the original large-scale AC-DC interconnected system often needs to be preprocessed, that is, the network scale is greatly simplified while the main dynamic response characteristics of the system are retained, so as to facilitate subsequent electromagnetic transient simulation modeling. Researchers have been committed to solving the problem of simplifying the system and improving the efficiency of transient analysis under the premise of retaining the original system characteristics and ensuring the calculation accuracy.

[0003] Therefore, at the present stage, a PSD-BPA data preprocessing method for electromagnetic transient modeling is needed to solve the above problems. SUMMARY

[0004] The application aims to provide a PSD-BPA data preprocessing method for electromagnetic transient modeling, which solves the technical problems existing in the prior art, that is, how to simplify the system and improve the efficiency of transient analysis under the premise of retaining the original system characteristics and ensuring the calculation accuracy.

[0005] To achieve the above-mentioned purpose, the technical scheme of the application is:

[0006] A PSD-BPA data preprocessing method for electromagnetic transient modeling, step one: first, identify and store the BPA data model, identify small reactance branches, 3-winding transformers, double-winding transformers, generator nodes and their control models;

[0007] Step two: iteratively find the small reactance branches, retain the starting node, annotate the intermediate and end nodes, replace the nodes of the related cards and equalize the parameters of the nodes;

[0008] Step three: equivalent condition judgment is performed on the transformers of the same substation, and the transformers meeting the conditions are combined;

[0009] Step four: the nodes of the generators and step-up transformers meeting the equivalent conditions in the same power plant are combined and parameters are converted, and the related control cards are processed in terms of parameter equivalence and annotation;

[0010] Step five: the power flow calculation results *.PFO files and the stability calculation results *.OUT files before and after the above processing are calculated and compared.

[0011] Further, the PSD-BPA data preprocessing method for electromagnetic transient modeling has the characteristics that in step one, various card types in the BPA data, that is, various electrical equipment models in the *.DAT file and the *.SWI file, such as generators, transformers, lines, and control models, are identified.

[0012] Further, the PSD-BPA data preprocessing method for electromagnetic transient modeling has the characteristics that in step two, by iteratively searching the small reactance branch identified, the starting node is retained, the intermediate node is annotated, and the related node parameters are converted, which can effectively reduce the number of branches and nodes and ensure that the power flow results are within the error range.

[0013] Further, the PSD-BPA data preprocessing method for electromagnetic transient modeling has the characteristics that in step three, the three-winding and double-winding differentiation, the three-winding identification of the same substation, the three-winding equivalent combination condition judgment, and the combined parameter conversion method are included.

[0014] Further, the PSD-BPA data preprocessing method for electromagnetic transient modeling has the characteristics that in step four, the generator nodes and step-up transformers of the same power plant are identified, the equivalent combination conditions are judged, the nodes are combined, and the combined parameter conversion method is included.

[0015] Further, the PSD-BPA data preprocessing method for electromagnetic transient modeling has the characteristics that in step five, the power flow *.DAT files and the stability *.SWI files before and after the calculation are calculated, the power flow calculation results *.PFO and the stability calculation results *.OUT files before and after the calculation are compared, and it is ensured that the calculation results are within the error range.

[0016] A computer readable storage medium stores one or more computer programs, which are executed by one or more processors to implement the PSD-BPA data preprocessing method for electromagnetic transient modeling as described above.

[0017] The application discloses a PSD-BPA data preprocessing system for electromagnetic transient modeling, and applies to a PSD-BPA data preprocessing method for electromagnetic transient modeling.

[0018] Compared with the prior art, the PSD-BPA data preprocessing system for electromagnetic transient modeling has the beneficial effects that:

[0019] One of the beneficial effects of the scheme is that the scheme firstly identifies and stores power system equipment models by analyzing BPA data cards; then reduces the number of nodes and the system scale from three aspects in the obtained equipment; namely (1) related nodes and branches are processed by small reactance branch iteration to reduce branches and nodes; (2) the modeling scale of a substation is reduced by equivalent merging of three-winding transformers and related nodes of the substation; and (3) the modeling scale of a power plant is reduced by equivalent merging of generator nodes and control models of the same power plant and boost transformers; finally, the modeling scale in electromagnetic transient simulation can be greatly reduced through all the processing steps, and the main grid structure of the power system is also reserved, thereby providing a basic guarantee for electromagnetic transient simulation modeling. The method has the characteristics of rapidness, accuracy, simplicity and easy implementation. BRIEF DESCRIPTION OF DRAWINGS

[0020] Figure 1 The BPA data preprocessing framework of the embodiment of the application is shown.

[0021] Figure 2 The flowchart of identifying three-winding transformers of the embodiment of the application is shown.

[0022] Figure 3 The flowchart of small reactance branch processing of the embodiment of the application is shown.

[0023] Figure 4 The flowchart of equivalent merging of three-winding transformers of the embodiment of the application is shown.

[0024] Figure 5 The flowchart of processing of generators and control cards of the embodiment of the application is shown.

[0025] Figure 6 The comparison chart of BPA data preprocessing of a substation of the embodiment of the application before and after is shown.

[0026] Figure 7 The geographical wiring diagram of a substation and a power plant before and after preprocessing of the embodiment of the application is shown. DETAILED DESCRIPTION

[0027] For the purpose of the present application, the technical solutions and advantages are more clearly and obviously understood, the present application is further described in detail below in combination with the drawings and examples. It should be understood that the specific examples described herein are only used to explain the present application, and are not used to limit the present application, that is, the described examples are only a part of the examples of the present application, but not all the examples. The components of the embodiments of the present application generally described and shown in the drawings herein can be arranged and designed in various different configurations.

[0028] Therefore, the detailed description of the embodiments of the present application provided below in the drawings is not intended to limit the scope of the claimed application, but only represents selected embodiments of the present application. Based on the embodiments of the present application, all other embodiments obtained by those skilled in the art without making creative efforts are within the scope of protection of the present application. It should be noted that the relational terms such as "first" and "second" and the like are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between the entities or operations.

[0029] Moreover, the term "comprising", "containing" or any other variant thereof is intended to cover non-exclusive inclusion, so that the process, method, article or device including a series of elements not only includes those elements, but also includes other elements not explicitly listed or inherent to such process, method, article or device. Without more limitations, the element defined by the statement "including a" does not exclude the presence of additional identical elements in the process, method, article or device including the element.

[0030] As Figure 1 shown, the present application is a PSD-BPA data preprocessing method for electromagnetic transient modeling, specifically comprising the following steps:

[0031] Step one: First, identify and store the BPA data model, identify small reactance branch, 3-winding transformer, double-winding transformer, generator node and its control model;

[0032] a. Identify small reactance branch: Small reactance branch is a short circuit used for fault test in power system, the feature of L card in BPA data *.DAT file is that the node name of node A and node B represents the two ends of the line, and the line parameters, if the reactance per unit value of the line is 0.0001 or 0.001, and there is no resistance, reactance and conductance parameter on the L card, such L card is small reactance branch.

[0033] b. Identify 3-winding: As Figure 2As shown, for identifying 3-winding transformer flow chart, the feature in BPA data *.DAT file is T card, which stores the node name of node A and node B representing the two ends of the transformer, and the parameters of the transformer. Since 3-winding transformer is represented by 3 double-winding transformer T cards, so its identification step is to sequentially read 3 T cards, record its node A and node B, judge whether the number of node A or node B of the last T card is 3, and the voltage levels of the remaining 3 nodes are different, then determine that the 3 T cards are a 3-winding transformer.

[0034] c. Identify double-winding: T cards that are not 3-winding transformers are double-winding transformers.

[0035] d. Identify generator nodes: The feature of power system nodes in BPA data *.DAT file is B card, including various B cards such as BS, BQ, BE, etc. If the maximum active power or actual active power parameter of this type of B card is greater than 0, then the node is a generator node. By matching the generator node name with the control model card node name in *.SWI file, the control model of the generator can be found.

[0036] Step two: Iterative search for small reactance branches, retain the starting node, annotate intermediate and end nodes, replace the nodes of related cards and the parameters of equivalent nodes;

[0037] a. Read a small reactance branch L card in the small reactance branch container;

[0038] b. Save the starting node A of the L card, and use its end node B as the starting point to iteratively find and save the L card and node connected to the end node B in the small reactance branch container;

[0039] c. Convert the constant active load P, constant reactive load Q, and active load adP, and reactive load adQ of the B cards of the N intermediate and end nodes to the corresponding parameters of the B card of the retained node A. The conversion method is as follows:

[0040]

[0041] In the formula: P A is the constant active load of the starting node A, P n is the constant active load of the nth node.

[0042]

[0043] In the formula: Q A is the constant reactive load of the starting node A, Q n is the constant reactive load of the nth node.

[0044]

[0045] Where: adP A adP is the admittance active load of the starting node A. n Let be the admittance active load of the nth node.

[0046]

[0047] In the formula: adQ A adQ is the admittance reactive load of the starting node A. n Let n be the admittance reactive load of the nth node.

[0048] d. Replace the nodes of the symmetrical line data card L, line high-resistance parameter data card L+, line zero-sequence parameter model card LO, line high-resistance zero-sequence parameter model card LO+, transformer data card T, and transformer zero-sequence parameter model card XO with the reserved node A;

[0049] e. Comment out the small reactor branch L card containing intermediate and terminal nodes in the *.DAT file;

[0050] f. Repeatedly query all L, LO, T, XO, L+, and LO+ cards, and mark the serial number on their parallel circuit parameter bits;

[0051] g. Verify whether the power flow calculation and stability calculation after the above processing are converged and the correctness of the results, and that the errors before and after are within a certain range.

[0052] Step 3: Perform equivalence condition assessment on transformers within the same substation, and merge transformers that meet the conditions into equivalent value pairs; this includes:

[0053] like Figure 2 As shown:

[0054] a. Using the current 3-winding transformer as a reference, read one 3-winding transformer in sequence;

[0055] b. Determine whether the high and medium voltage side nodes of this 3-winding transformer are the same as those of the previous 3-winding transformer. If they are the same, it is a 3-winding transformer from the same substation. Continue reading 1 more 3-winding transformer.

[0056] c. If they are different, determine whether the capacity of the high, medium and low voltage sides of the N 3-winding transformers that have been read is the same as that of the reference 3-winding transformer; if they are different, remove the reference 3-winding transformer from the stack, and set the next one as the reference 3-winding transformer, and continue reading and judging.

[0057] d. If they are the same, then perform an equal-value merging process:

[0058] (1) The T-card parameters of the N 3-winding transformers to be merged, corresponding to the rated capacity MVA, copper loss equivalent resistance R, leakage reactance XL, iron loss equivalent conductance G, excitation admittance B, etc. on the high, medium, and low voltage sides, are respectively converted to the T-card of the reference 3-winding transformer A. The calculation formulas for each parameter are as follows:

[0059]

[0060] Where: MVA A The rated capacity on the T card of the reference 3-winding transformer A, in MVA n This is the rated capacity of the nth winding with 3 windings.

[0061]

[0062] In the formula: R A The equivalent copper loss resistance R on the T card of the reference 3 winding transformer A n Let be the copper loss equivalent resistance of the nth winding with 3 windings.

[0063]

[0064] In the formula: XL A The leakage reactance on the T-card of the reference 3-winding transformer A, XL n Let be the leakage reactance of the nth winding with 3 windings.

[0065]

[0066] Where: G A The equivalent iron loss conductance on the T card of the reference 3 winding transformer A, G n Let be the iron loss equivalent conductance of the nth winding (3rd winding).

[0067]

[0068] In the formula: B A The excitation admittance on the T card of reference winding transformer A, B n Let be the excitation admittance of the nth winding with 3 windings.

[0069] (2) Replace the L, LO, T, XO, L+, LO+ card nodes that have the same high, medium and low voltage side node names as the N 3-winding transformers that are being merged with the high, medium and low voltage side node names of the reference 3-winding transformer respectively.

[0070] (3) Comment out the merged N 3-winding T cards and non-reference 3-winding node B cards in the *.DAT file;

[0071] The constant active load P, constant reactive load Q, and admittance active load adP and admittance reactive load adQ of the node B card of the high, medium and low voltage sides of the N 3-winding units to be merged are respectively converted to the corresponding parameters of the node B card of the high, medium and low voltage sides of the base 3-winding unit. The conversion formulas are formula (1), formula (2), formula (3) and formula (4).

[0072] e. Repeatedly query all L, LO, T, XO, L+, and LO+ cards, and mark the serial number on their parallel circuit parameter bits;

[0073] h. Verify whether the power flow calculation and stability calculation after the above processing are converged and the correctness of the results, and that the errors before and after are within a certain range.

[0074] Step 4: Merge nodes and convert parameters for generators and step-up transformers in the same power plant that meet the equivalence conditions, and perform parameter equivalence and annotation processing on relevant control cards;

[0075] a. Read a dual-winding transformer T-card (TAB);

[0076] b. Traverse the T-card container of the dual-winding transformer;

[0077] c. Determine if there exists a T card in the container that has a node with one end as TAB and the other end as a generator node; otherwise, execute a.

[0078] d. If so, store the generator node B card and the dual-winding step-up transformer T card of the same power plant;

[0079] e. Determine whether the capacity of the T cards of the N dual-winding step-up transformers stored is the same as that of TAB, and whether the capacity of their respective corresponding M cards is also the same. If not, then execute a.

[0080] f. If so, then perform equal-value merging:

[0081] (1) Convert the T-card parameters of the N double-winding step-up transformers to be merged to TAB. The conversion formulas are (5), (6), (7), (8), and (9).

[0082] (2) The constant active load P, constant reactive load Q, and admittance active load adP and admittance reactive load adQ of the N double-winding generator nodes B cards to be merged are converted to the corresponding parameters of the generator nodes B cards of TAB. The conversion formulas are formula (1), formula (2), formula (3), formula (4) and the following formulas:

[0083]

[0084] Where: maxPA The maximum active power output of the starting node A is maxP. n This represents the maximum active power output of the nth node.

[0085]

[0086] In the formula: realP A For the actual active power output of the starting node A, realP n This represents the actual active power output of the nth node.

[0087]

[0088] Where: maxQ A maxQ represents the maximum reactive power output of the starting node A. n This represents the maximum reactive power output of the nth node.

[0089]

[0090] Where: minQ A minQ represents the minimum reactive power output of the starting node A. n This represents the minimum reactive power output of the nth node.

[0091] (3) Comment out the T cards of the N double windings and their generator node B cards that are merged in the *.DAT file;

[0092] (4) Convert the M-card parameters of the N dual-winding units to be merged to the M-card of the generator node in TAB. According to the capacity weighting method, the capacity conversion formula on the M-card is as follows:

[0093]

[0094] Where: MVA M This indicates the rated capacity (MVA) on the M card of the generator node in TAB. n This represents the rated capacity of the M card corresponding to the nth generator node.

[0095] (5) The parameters of the control card models of motors, excitation, speed regulation, PSS, prime movers, etc., that have the same name as the generator node to be merged in *.SWI are weighted and averaged onto the control models corresponding to the retained generator nodes.

[0096] (6) Locate and annotate the control card models in *.SWI that have the same name as the generator node being merged, such as motor, excitation, speed regulation, PSS, prime mover, etc.

[0097] g. Verify whether the power flow calculation and stability calculation after the above processing are converged and the correctness of the results, and that the errors before and after are within a certain range.

[0098] Step 5: Calculate and compare the power flow calculation results (*.PFO file) and stability calculation results (*.OUT file) before and after the above processing. The results should converge, and the errors should be within a certain range. In other words, in the simplified power grid, the power values ​​of equivalent loads and equivalent generators need to be determined through static power flow comparison. This involves comparing the active power and bus voltage of the retained lines before and after equivalence, and observing whether the errors are within acceptable limits. Static power flow comparison is the prerequisite and foundation for dynamic verification. Only by meeting this requirement can the error of the initial stability calculation values ​​before and after preprocessing be guaranteed to be small. If the power flow difference between the simplified power grid and the original power grid is large, the stability calculation results will certainly not be close, seriously affecting the effectiveness of dynamic equivalence.

[0099] Static power flow evaluation involves comparing the active power and bus voltage of the retained lines before and after the equivalent value is calculated. The evaluation index is that the relative error of the absolute value before and after the equivalent value is within 5%.

[0100]

[0101] In the formula: x 前 This represents the bus voltage, active power, and reactive power of the node before processing, x 后 This indicates the bus voltage, active power, and reactive power of the node after processing.

[0102] The above are preferred embodiments of the present invention. Any changes made to the technical solution of the present invention that do not exceed the scope of the technical solution of the present invention shall fall within the protection scope of the present invention.

Claims

1. A PSD-BPA data preprocessing method for electromagnetic transient modeling, characterized in that, Includes the following steps: Step 1: First, identify and store the BPA data model, including the small reactor branch, the 3-winding transformer, the 2-winding transformer, the generator node, and their control models; Step 2: Iteratively search the small reactor branch, retain the starting node, comment out the middle and ending nodes, replace the nodes of the relevant cards and equalize the parameters of the nodes; a. Read a small reactor branch L card from the small reactor branch container; b. Save the starting node A of the L card, and use its ending node B as the starting point to iteratively find and save the L cards and nodes connected to the ending node B in the small reactor branch container; c. Convert the constant active load P, constant reactive load Q, and admittance active load adP and admittance reactive load adQ parameters of the B cards of the N nodes in the middle and at the end to the corresponding parameters of the B card of the retained node A. The conversion method is as follows: (1) In the formula: pA is the constant active load at the starting node A. The constant active power load of the nth node; (2) In the formula: QA is the constant reactive load at the starting node A. The constant reactive load of the nth node; (3) In the formula: The admittance active load of the starting node A, Let n be the admittance active load of the nth node; (4) In the formula: For the reactive load with parallel admittance at starting node A, Let n be the reactive load with parallel admittance at the nth node; d. Replace the nodes of the symmetrical line data card L card, line high-resistance parameter data card L+ card, line zero-sequence parameter model card LO card, line high-resistance zero-sequence parameter model card LO+ card, transformer data card T card, and transformer zero-sequence parameter model card XO card, which contain intermediate and terminal nodes, with the reserved node A; e. Comment out the small reactor branch L card containing intermediate and terminal nodes in the *.DAT file; f. Repeatedly query all L, LO, T, XO, L+, and LO+ cards, and mark the serial number on their parallel circuit parameter bits; g. Verify whether the power flow calculation and stability calculation after the above processing are converged and the correctness of the results, and that the errors before and after are within a certain range; Step 3: Perform equivalence condition judgment on transformers in the same substation, and merge transformers that meet the conditions; Step 4: Merge nodes and convert parameters for generators and step-up transformers in the same power plant that meet the equivalence conditions, and perform parameter equivalence and annotation processing on the relevant control cards; Step 5: Calculate and compare the power flow calculation results (*.PFO file) and stability calculation results (*.OUT file) before and after the above processing.

2. The PSD-BPA data preprocessing method for electromagnetic transient modeling according to claim 1, characterized in that, Step one involves identifying various cards in the BPA data, namely, various electrical equipment models in the *.DAT and *.SWI files. These electrical equipment models include generators, transformers, lines, reactive power compensation equipment, and control models.

3. The PSD-BPA data preprocessing method for electromagnetic transient modeling according to claim 2, characterized in that, In step two, the identified small reactance branches are iteratively searched, the starting node is retained, the intermediate nodes are annotated, and the relevant node parameters are converted to reduce the number of branches and nodes and ensure that the power flow results are within the error range.

4. The PSD-BPA data preprocessing method for electromagnetic transient modeling according to claim 3, characterized in that, Step three specifically involves: distinguishing between 3-winding and dual-winding systems, identifying 3-winding systems in the same substation, determining the conditions for equivalent merging of 3-winding systems, and converting merging parameters.

5. The PSD-BPA data preprocessing method for electromagnetic transient modeling according to claim 4, characterized in that, Step four includes identifying generator nodes and step-up transformers in the same power plant, determining the conditions for equivalent merging, processing merged nodes, and methods for converting merging parameters.

6. The PSD-BPA data preprocessing method for electromagnetic transient modeling according to claim 5, characterized in that, In step five, the power flow *.DAT file and stability *.SWI file are calculated before and after processing. The power flow calculation results *.PFO and stability calculation results *.OUT files are compared before and after processing, and the calculation results are ensured to be within the error range.

7. A computer-readable storage medium, characterized in that, The computer-readable storage medium stores one or more computer programs that, when executed by one or more processors, implement a PSD-BPA data preprocessing method for electromagnetic transient modeling as described in any one of claims 1-6.

8. A PSD-BPA data preprocessing system for electromagnetic transient modeling, characterized in that, This method is applied to the PSD-BPA data preprocessing method for electromagnetic transient modeling as described in any one of claims 1-6.

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