Thermal power plant main wiring self-adaptive short-circuit current calculation method and system based on topological linkage
By establishing a component model parameter library and building a short-circuit calculation electrical main wiring model, the accuracy and adaptability problems of traditional short-circuit calculation are solved, high-precision and fast short-circuit current calculation and fault current acquisition are achieved, and human-computer interaction functions are provided.
Patent Information
- Application Number
- CN202510374723.6
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-03-27
- Publication Date
- 2025-07-04
AI Technical Summary
In traditional methods, the short-circuit calculation of multiple units relies on manual calculation, the model accuracy is insufficient, the calculation result error is large, and it does not have adaptive main wiring conditions, so it is difficult to obtain the fault current flowing through the CT installed at different physical locations.
Establish a component model parameter library, build a short-circuit calculation electrical main wiring model, formulate graph theory rules to search for the shortest fault path with ground potential as the target, form a short-circuit impedance unit, calculate the unity of the short-circuit current unit, and perform data storage and human-computer interaction.
It realizes high-precision and fast short-circuit calculation results, is adaptable, can accurately obtain the fault current of each component of the fault path, and supports human-computer interaction function.
Smart Images
Figure CN120256773A_ABST
Abstract
Description
Technical Field
[0001] The present invention belongs to the field of relay protection of power systems, and particularly relates to a method and system for calculating adaptive short-circuit current based on the topological linkage of the main wiring of a power plant. Background Art
[0002] As one of the typical representatives of the energy sources of the new power system, thermal power plants will play multiple roles such as power generation, peak shaving, and frequency modulation in the new power system. The safe and stable operation of large thermal power generating units will affect the operation stability of the power system and the vital interests and power consumption safety of electricity users. In the case of a large amount of new energy access, higher requirements are put forward for the safe and reliable operation of the new power system. Short-circuit calculation is an essential step for the accuracy of relay protection settings of large thermal power units, the selection of equipment, and the dynamic and thermal stability of equipment after new energy is connected to thermal power plants. Therefore, exploring a short-circuit calculation method that can adapt to the main wiring on the power supply side is of great significance for the safe operation of power supply equipment and the power grid.
[0003] Currently, for power plants with multiple units in operation, the short-circuit calculation work in the traditional method basically relies on manual calculation, which is cumbersome and does not have the working conditions to adapt to the main wiring; its short-circuit calculation uses approximate algorithms, ignoring the inequality between the positive-sequence impedance and the negative-sequence impedance of rotating equipment, with insufficient model accuracy and large calculation result errors. On the other hand, the short-circuit calculation results of multiple units in the traditional method are the total fault current at the electrical fault location point, rather than the fault current provided by the physical positions of each power supply point. To obtain the fault current flowing through the CT installed at different physical positions, mathematical calculations are required. Summary of the Invention
[0004] The purpose of the present invention is to provide a method and system for calculating adaptive short-circuit current based on the topological linkage of the main wiring of a power plant, aiming at the problems that in the traditional method of short-circuit calculation for multiple units, on the one hand, it relies on manual calculation, with insufficient model accuracy, large calculation result errors, cumbersome steps and lack of adaptability to the main wiring working conditions; on the other hand, it is difficult to obtain the fault current flowing through the CT installed at different physical positions.
[0005] To achieve the above purpose, the present invention adopts the following technical solutions: The method for calculating adaptive short-circuit current based on the topological linkage of the main wiring of a thermal power plant includes: Step 1: Establish a component model parameter library; Step 2: Based on the component model parameter library, build a short-circuit calculation electrical main wiring model; Step 3: Formulate graph theory rules for different voltage levels in the short-circuit calculation electrical main connection model, search for the shortest fault path method with the ground potential as the target, form short-circuit paths formed by the individual actions of different power sources, form the per-unit value sequence of the impedance of each path element into the per-unit value of the short-circuit impedance, form the per-unit value of the short-circuit current based on the per-unit value of the short-circuit impedance, and form the nominal value of the short-circuit current based on the per-unit value of the short-circuit current; Step 4: Based on the nominal value of the short-circuit current, store and retrieve the short-circuit calculation result data according to the node definition rules, form the short-circuit calculation result and have a man-machine interaction function.
[0006] A further improvement of the present invention is that the establishment of the component model parameter library in Step 1 includes single-machine infinite equivalent power source parameters, generator parameters, transformer parameters, and load parameters; Wherein the generator parameters include the sub-transient reactance per-unit value X d’’ 、the transient reactance per-unit value X d 、the synchronous reactance X d per-unit value, the negative-sequence reactance per-unit value X2, the zero-sequence reactance per-unit value X0, and the rated capacity S G of the generator; The single-machine infinite equivalent power source parameters include the equivalent impedance per-unit value Xs and the base capacity S B ; The transformer parameters include the short-circuit voltage percentage U k % and the rated capacity S T of the transformer; The load parameters include the positive-sequence reactance X1, the negative-sequence reactance per-unit value X2, and the zero-sequence reactance X0, and the rated capacity S G of the generator.
[0007] A further improvement of the present invention is that in Step 2, the establishment of the short-circuit calculation electrical main connection model based on the component model parameter library refers to constructing an electrical main connection model adapted to the actual power plant's main connection according to the component models.
[0008] A further improvement of the present invention is that in Step 3, formulating graph theory rules for different voltage levels in the short-circuit calculation electrical main connection model means that when there are m generators and m main transformers connected to the grid system S for operation, define the node positions according to the voltage levels from high to low, and each node represents a different voltage level.
[0009] A further improvement of the present invention is that in Step 3, the method of searching for the shortest fault path with the ground potential as the target means that taking one of the units as the power source, simulating faults at nodes of different voltage levels, treating other power sources as zero potential, and searching for the shortest path from the power source according to the ground potential search rules to form the short-circuit impedance.
[0010] A further improvement of the present invention lies in that in step three, the method of formulating graph theory rules for different voltage levels in the short-circuit calculation electrical main connection model and searching for the shortest fault path with the ground potential as the target forms short-circuit paths formed by the separate actions of different power sources. The per-unit value sequence of the impedance of each path element forms the per-unit value of the short-circuit impedance. The per-unit value of the short-circuit current is formed based on the per-unit value of the short-circuit impedance, and the nominal value of the short-circuit current is formed based on the per-unit value of the short-circuit current, which means that each power source searches for the shortest fault path with the ground potential as the target to generate an equivalent reactance. Repeat the above process to form a per-unit value of short-circuit impedance P. (1) According to the per-unit value of short-circuit impedance P, the per-unit value of short-circuit current Q is formed according to Equation (2), where the constant K represents different types of short-circuit values, including three-phase short-circuit K = 1, two-phase short-circuit K = 1.732, and three-phase short-circuit K = 3. (2) The per-unit value of short-circuit current Q forms the nominal value of short-circuit current Q* according to Equation (3). In Equation (3), The base capacity, and Uj is the base voltage at different voltage levels. (3).
[0011] A further improvement of the present invention lies in that in step four, the storage and retrieval of the short-circuit calculation result data according to the node definition rule based on the nominal value of the short-circuit current means that the short-circuit calculation results are stored in the order of the unit rule numbers from small to large, and the per-unit value sequence of the impedance calculated in step three is stored, leaving a retrievable window. The formation of the short-circuit calculation result and the provision of a human-computer interaction function mean that the calculated results support export in the forms of xls, csv, and txt.
[0012] The topology-linked adaptive short-circuit current calculation system for the main connection of a thermal power plant includes: A model parameter library establishment module for establishing a component model parameter library; A main connection model building module for building a short-circuit calculation electrical main connection model based on the component model parameter library; A first calculation module for formulating graph theory rules for different voltage levels in the short-circuit calculation electrical main connection model, searching for the shortest fault path with the ground potential as the target, forming short-circuit paths formed by the separate actions of different power sources, forming the per-unit value of the short-circuit impedance from the per-unit value sequence of the impedance of each path element, forming the per-unit value of the short-circuit current based on the per-unit value of the short-circuit impedance, and forming the nominal value of the short-circuit current based on the per-unit value of the short-circuit current; The second calculation module stores and retrieves the short-circuit calculation result data according to the node definition rules based on the nominal value of the short-circuit current, forms the short-circuit calculation result and has the human-computer interaction function.
[0013] A further improvement of the present invention lies in that the establishment of the component model parameter library in the model parameter library establishment module includes the parameters of the single-machine infinite equivalent power supply, the parameters of the generator, the parameters of the transformer, and the parameters of the load; Wherein the generator parameters include the subtransient reactance per unit value X d’’ , the transient reactance per unit value X d , the synchronous reactance X d per unit value, the negative-sequence reactance per unit value X2, the zero-sequence reactance per unit value X0, and the rated capacity S G of the generator; The parameters of the single-machine infinite equivalent power supply include the equivalent impedance per unit value Xs and the base capacity S B ; The transformer parameters include the short-circuit voltage percentage U k %, and the rated capacity S T of the transformer; The load parameters include the positive-sequence reactance X1, the negative-sequence reactance per unit value X2, and the zero-sequence reactance X0, and the rated capacity S G of the generator.
[0014] A further improvement of the present invention lies in that the establishment of the electrical main connection model in the main connection model building module based on the component model parameter library refers to constructing an electrical main connection model adapted to the actual power plant's main connection according to the component models.
[0015] Compared with the prior art, the present invention has at least the following beneficial technical effects: The present invention provides a method and system for adaptively calculating short-circuit current based on the topological linkage of the main wiring of a power plant. First, a component model parameter library is established; secondly, components are cited to build a short-circuit calculation electrical main wiring model; then, graph theory rules are formulated according to different voltage levels in the electrical main wiring model, and the shortest fault path method is searched with the ground potential as the target to form the per-unit value of the short-circuit impedance; the short-circuit impedance of different units is formed by using a computer; finally, the per-unit value of the short-circuit current can be formed according to the per-unit value of the short-circuit impedance, and the short-circuit calculation result data is stored and can be retrieved, and the short-circuit calculation result has a human-computer interaction function. The short-circuit calculation method and system proposed by the present invention construct a main wiring model with high-precision component parameters, and can calculate the short-circuit current provided by different units at the fault point by using the linear power superposition theorem. The shortest path method is searched with the ground potential as the target, and the current flowing through the components of the shortest fault path can be formed. Compared with the existing methods, on the one hand, this method has high precision, accuracy, speed and self-adaptability, and on the other hand, the fault current of each component on the fault path can be effectively obtained. This system has a human-computer interaction function, and can realize more accurate and efficient short-circuit calculation results. BRIEF DESCRIPTION OF THE DRAWINGS
[0016] In order to more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the following will briefly introduce the drawings required for the description of the specific embodiments or the prior art. Obviously, the drawings in the following description are some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can be obtained based on these drawings.
[0017] Figure 1 It is a flowchart of the method for adaptively calculating short-circuit current based on the topological linkage of the main wiring of a thermal power plant according to the present invention.
[0018] Figure 2 It is a schematic diagram of the short-circuit calculation model of the electrical main wiring of a power plant with multiple units according to the present invention.
[0019] Figure 3 It is a schematic diagram of the electrical main wiring of a thermal power plant with 4 units.
[0020] Figure 4 For Figure 3 a schematic diagram of building a short-circuit calculation electrical main wiring model with component parameters in
[0021] Figure 5 It is a structural block diagram of the system for adaptively calculating short-circuit current based on the topological linkage of the main wiring of a thermal power plant according to the present invention. DETAILED DESCRIPTION OF THE EMBODIMENTS
[0022] In the following text, only some exemplary embodiments are briefly described. As those skilled in the art can recognize, the described embodiments can be modified in various different ways without departing from the spirit or scope of the present invention. Therefore, the accompanying drawings and description are considered to be exemplary in nature and not restrictive.
[0023] It should be understood that when used in this specification and the appended claims, the terms "comprising" and "including" indicate the presence of the described features, wholes, steps, operations, elements, and / or components, but do not preclude the presence or addition of one or more other features, wholes, steps, operations, elements, components, and / or their combinations.
[0024] It should also be understood that the terms used in the specification of the present invention are for the purpose of describing particular embodiments only and are not intended to limit the present invention. As used in the specification of the present invention and the appended claims, unless the context clearly indicates otherwise, the singular forms "a", "an", and "the" are intended to include the plural forms.
[0025] It should be further understood that the term "and / or" used in the specification of the present invention and the appended claims refers to any combination and all possible combinations of one or more of the associated listed items, and includes these combinations.
[0026] Various schematic structural diagrams according to the disclosed embodiments of the present invention are shown in the accompanying drawings. These figures are not drawn to scale, where for the purpose of clear expression, some details are enlarged and some details may be omitted. The shapes of various regions and layers shown in the figures and their relative sizes and positional relationships are only exemplary, and in practice, there may be deviations due to manufacturing tolerances or technical limitations, and those skilled in the art can design regions / layers with different shapes, sizes, and relative positions according to actual needs.
[0027] The embodiments of the present invention will be described in detail below with reference to the accompanying drawings.
[0028] Embodiment 1 The adaptive short-circuit current calculation method for the main electrical connection of a thermal power plant based on topological linkage provided by the present invention includes: First, establish a component model parameter library; Second, based on the component model parameter library, build a short-circuit calculation electrical main connection model; Then, formulate graph theory rules for different voltage levels in the short-circuit calculation electrical main connection model, and use the method of searching for the shortest fault path with the ground potential as the target to form short-circuit paths formed by the individual actions of different power supply points. The per-unit value sequence of the impedance of each path element forms the per-unit value of the short-circuit impedance. The per-unit value of the short-circuit current is formed according to the per-unit value of the short-circuit impedance, and the nominal value of the short-circuit current is formed according to the per-unit value of the short-circuit current; Finally, based on the nominal value of the short-circuit current, store and retrieve the short-circuit calculation result data according to the node definition rule to form the short-circuit calculation result and have a man-machine interaction function. The short-circuit calculation method and system proposed by the present invention construct the main connection model with high-precision component parameters, use the linear power superposition theorem to calculate the short-circuit current provided by different units at the fault point, and use the method of searching for the shortest path with the ground potential as the target to form the current flowing through the components of the shortest fault path. Compared with the existing methods, on the one hand, this method has high precision, accuracy, speed and self-adaptability, and on the other hand, it can effectively obtain the fault current of each component on the fault path. This system also has a man-machine interaction function to achieve more accurate and efficient short-circuit calculation results.
[0029] Embodiment 2 As Figure 2 shown, the schematic diagram of the short-circuit calculation model for the main electrical connection of a multi-unit power plant includes m generators, m main transformers, a single-machine infinite system S, m excitation transformers, and m auxiliary transformers; As Figure 1 shown, the adaptive short-circuit current calculation method and system for the main electrical connection of a thermal power plant based on topological linkage construct the main connection model with high-precision component parameters, use the linear power superposition theorem to calculate the short-circuit current provided by different units at the fault point, and use the method of searching for the shortest path with the ground potential as the target to form the current flowing through the components of the shortest fault path, and form the short-circuit calculation result with a man-machine interaction function.
[0030] The method specifically includes the following steps: Step 1: Establish a component model parameter library (single-machine infinite equivalent power supply, generator, transformer, load); Step 2: Based on the component model parameter library, build a short-circuit calculation electrical main connection model; Step 3: Formulate graph theory rules for different voltage levels in the short-circuit calculation electrical main connection model, and use the method of searching for the shortest fault path with the ground potential as the target to form short-circuit paths formed by the individual actions of different power supply points. The per-unit value sequence of the impedance of each path element forms the per-unit value of the short-circuit impedance. The per-unit value of the short-circuit current is formed according to the per-unit value of the short-circuit impedance, and the nominal value of the short-circuit current is formed according to the per-unit value of the short-circuit current.
[0031] Step 4: Based on the short-circuit current in actual value, store and retrieve the short-circuit calculation result data according to the node definition rules, form the short-circuit calculation result, and have the human-computer interaction function.
[0032] The component model parameter library established in Step 1 of the present invention includes single-machine infinite equivalent power sources, generators, transformers, loads, etc.
[0033] Among them, the generator parameters include the subtransient reactance per unit value X d ’’ 、the transient reactance per unit value X d 、the synchronous reactance X d per unit value, the negative-sequence reactance per unit value X2, the zero-sequence reactance per unit value X0, and the rated capacity S G of the generator, etc.; The parameters of the single-machine infinite equivalent power source include the equivalent impedance per unit value Xs, the base capacity S B of the power source, etc.; The parameters of the transformer include the short-circuit voltage percentage U k %, the rated capacity S T of the transformer, etc.
[0034] The parameters of the load include the positive-sequence reactance X1, the negative-sequence reactance per unit value X2, the zero-sequence reactance X0, and the rated capacity S G of the generator, etc.
[0035] The short-circuit calculation electrical main connection model established in Step 2 of the present invention refers to constructing an electrical main connection model adapted to the actual power plant's main connection according to the component models.
[0036] The method of formulating graph theory rules for different voltage levels in the short-circuit calculation electrical main connection model in Step 3 of the present invention, searching for the shortest fault path with the ground potential as the target, forming short-circuit paths formed by the separate action of different power sources, forming the short-circuit impedance per unit value sequence of each path component impedance, forming the short-circuit current per unit value according to the short-circuit impedance per unit value, and forming the short-circuit current in actual value according to the short-circuit current per unit value, includes: The method of formulating graph theory rules for different voltage levels in the electrical main connection model refers to when there are m generators and m main transformers operating in the grid-connected system S, defining the node positions according to the voltage levels from high to low, and each node represents a different voltage level.
[0037] The method of searching for the shortest fault path with the ground potential as the target refers to taking one of the units as the power source, simulating faults at nodes of different voltage levels, treating other power sources as zero potential, and searching for the shortest path from the power source according to the ground potential search rule to form the short-circuit impedance.
[0038] The formation of the per-unit value sequence P of the short-circuit impedance formed by the separate actions of different power supply points refers to each power supply point searching for the shortest fault path with the ground potential as the target to generate an equivalent reactance. , and repeat the above process to form a per-unit value P of the short-circuit impedance as shown in Equation (1).
[0039] (1) In this embodiment, in step three, according to the per-unit value P of the short-circuit impedance formed, the per-unit value Q of the short-circuit current value can be formed according to Equation (2), where the constant K represents different types of short-circuit values (K = 1 for three-phase short-circuit, K = 1.732 for two-phase short-circuit, K = 3 for three-phase short-circuit).
[0040] (2) In this embodiment, in step three, the per-unit value Q of the short-circuit current forms the nominal value Q* of the short-circuit current according to Equation (3). In Equation (3), the base capacity, and Uj is the base voltage at different voltage levels.
[0041] (3) In step four of the present invention, the storage and retrieval of the short-circuit calculation result data based on the nominal value of the short-circuit current according to the node definition rule refers to storing the short-circuit calculation result in ascending order of the unit rule number and storing the per-unit value sequence of the impedance calculated in step three, leaving a retrievable window.
[0042] The formation of the short-circuit calculation result with a human-computer interaction function described in step four of the present invention means that the calculated results support export in forms such as xls, csv, and txt.
[0043] Embodiment 3 As Figure 3 shown, taking the electrical main connection diagram of a thermal power plant with 4 units as an example, it includes 4 generators with a capacity of 600 MW and a rated power factor of 0.9, a terminal voltage of 22 kV, 4 main transformers with a capacity of 720 MVA, 4 high-voltage auxiliary transformers with a capacity of 63 MVA, and 4 excitation transformers with a capacity of 6.6 MVA.
[0044] Step 1: Establish a parameter library for generators, main transformers, high-voltage auxiliary transformers, excitation transformers, and infinite bus systems. Based on the factory manufacturing parameters of generators, main transformers, high-voltage auxiliary transformers, and excitation transformers, as well as the impedance of the infinite bus system in the large mode and small mode provided by a certain power dispatching control center, its parameter library is shown in Table 1, and the component parameters are associated with their corresponding graphics.
[0045] Table 2-13 Per-unit impedance values and capacities of each component
[0046] Step 2: Taking the schematic diagram of the electrical main connection of 4 units in a thermal power plant as an example, build a short-circuit calculation electrical main connection model according to the component parameters associated in Step 1, as Figure 4 shown.
[0047] Step 3: As Figure 4 shown, taking the three-phase short-circuit fault at point K2 of the generator as an example, with 4 generators and the single-machine infinite system as the power supply points, search for the shortest fault path. When each power supply point acts alone, other power supply points are treated as ground potential. Among them, the path formed by the single-machine infinite system is as shown in the red part of Figure 4 , the power supply point of the 1st generator is as shown in the green path in the figure. The separate actions of the power supply points of the 2nd - 4th generators are similar to the single-machine infinite system. The sequence of per-unit values of the three-phase short-circuit impedance formed by the separate actions of different power supply points is shown in the following formula (4).
[0048] (4) In this embodiment, in Step 3, according to the per-unit value p of the short-circuit impedance formed, the per-unit value Q of the short-circuit current value can be formed according to formula (2) as shown in formula (5).
[0049] (5) In this embodiment, in Step 3, the per-unit value Q of the short-circuit impedance forms the nominal value Q* of the short-circuit current according to formula (6). In formula (6), the base capacity (100 MVA), and Uj is the base voltage at the k2 voltage level.
[0050] (6) Among them, the sequence value P of the equivalent impedance for two-phase short circuit, the ground potential search path considers the unequal conditions of the positive-sequence impedance and negative-sequence impedance of the rotating element. The sequence value P of the equivalent impedance for single-phase short circuit considers the positive-sequence impedance, negative-sequence impedance, and zero-sequence impedance of the elements on the shortest fault path. Repeating Step 3 can obtain the nominal values of the short-circuit current for different fault types.
[0051] Step 4: Store and retrieve the short-circuit calculation result data according to the node definition rule for the nominal value of the short-circuit current, forming a short-circuit calculation result with a human-computer interaction function. The data supports export in csv, xls, and txt file formats.
[0052] Since the short-circuit model of this electrical main connection can adapt to changes in the operation mode of the in-plant generator sets, if a certain generator set is taken out of operation, the circuit topology automatically recognizes that the component is open-circuited, and its corresponding impedance is ∞, which does not affect the fault current provided by other generator sets to this fault point.
[0053] Example 4 As Figure 5As shown in the figure, the adaptive short-circuit current calculation system for the main electrical connection of a thermal power plant based on topological linkage provided by the present invention includes: A model parameter library establishment module for establishing a component model parameter library; A main electrical connection model construction module for constructing a short-circuit calculation electrical main connection model based on the component model parameter library; A first calculation module that formulates graph theory rules for different voltage levels in the short-circuit calculation electrical main connection model, searches for the shortest fault path method with the ground potential as the target, forms short-circuit paths formed by the individual actions of different power sources, forms a short-circuit impedance per-unit value sequence for each path component impedance, forms a short-circuit current per-unit value based on the short-circuit impedance per-unit value, and forms a short-circuit current in nominal value based on the short-circuit current per-unit value; A second calculation module that stores and retrieves short-circuit calculation result data according to the node definition rules based on the short-circuit current in nominal value, forms short-circuit calculation results and has a human-computer interaction function.
[0054] In this embodiment, the establishment of the component model parameter library in the model parameter library establishment module includes single-machine infinite equivalent power source parameters, generator parameters, transformer parameters, and load parameters; Among them, the generator parameters include the subtransient reactance per-unit value X d’’ , the transient reactance per-unit value X d , the synchronous reactance X d per-unit value, the negative-sequence reactance per-unit value X2, the zero-sequence reactance per-unit value X0, and the generator rated capacity S G ; The single-machine infinite equivalent power source parameters include the equivalent impedance per-unit value Xs and the base capacity S B ; The transformer parameters include the short-circuit voltage percentage U k % and the transformer rated capacity S T ; The load parameters include the positive-sequence reactance X1, the negative-sequence reactance per-unit value X2, and the zero-sequence reactance X0, and the generator rated capacity S G .
[0055] In this embodiment, the construction of the short-circuit calculation electrical main connection model based on the component model parameter library in the main electrical connection model construction module means constructing an electrical main connection model adapted to the actual power plant's main electrical connection according to the component models.
[0056] The foregoing has shown and described the basic principles, main features and advantages of the present invention. For those skilled in the art, it is obvious that the present invention is not limited to the details of the above-mentioned exemplary embodiments, and without departing from the spirit or basic features of the present invention, the present invention can be implemented in other specific forms. Therefore, from any point of view, the embodiments should be regarded as exemplary and non-limiting. The scope of the present invention is defined by the appended claims rather than the above description. Therefore, all changes falling within the meaning and scope of the equivalent elements of the claims are intended to be embraced within the present invention. Any reference signs in the claims should not be construed as limiting the claims involved.
[0057] In addition, it should be understood that although this specification is described according to embodiments, not every embodiment only contains an independent technical solution. This narrative way of the specification is only for clarity. Those skilled in the art should regard the specification as a whole, and the technical solutions in each embodiment can also be appropriately combined to form other embodiments that can be understood by those skilled in the art. The above content is only to illustrate the technical idea of the present invention and cannot be used to limit the protection scope of the present invention. Any changes made on the basis of the technical solution according to the technical idea proposed by the present invention fall within the protection scope of the claims of the present invention.
Claims
1. A method for calculating the adaptive short-circuit current of the main wiring of a thermal power plant based on topological linkage, characterized in that, including: Step 1: Establish a component model parameter library; Step 2: Based on the component model parameter library, build an electrical main connection model for short-circuit calculation; Step 3: Formulate graph theory rules for different voltage levels in the electrical main connection model for short-circuit calculation, search for the shortest fault path method with the ground potential as the target, form short-circuit paths formed by the separate action of different power sources, form the per-unit value sequence of the impedance of each path element into the per-unit value of the short-circuit impedance, form the per-unit value of the short-circuit current according to the per-unit value of the short-circuit impedance, and form the nominal value of the short-circuit current according to the per-unit value of the short-circuit current; Step 4: Based on the nominal value of the short-circuit current, store and retrieve the short-circuit calculation result data according to the node definition rules, form the short-circuit calculation result and have a human-computer interaction function.
2. The adaptive short-circuit current calculation method for the main wiring of a thermal power plant based on topological linkage according to claim 1, wherein, The establishment of the component model parameter library described in Step 1 includes the parameters of the single-machine infinite bus equivalent power source, generator parameters, transformer parameters, and load parameters; Among them, the generator parameters include the per-unit value of the subtransient reactance X d’’ , the per-unit value of the transient reactance X d , the synchronous reactance X d per-unit value, the per-unit value of the negative-sequence reactance X2, the per-unit value of the zero-sequence reactance X0, and the rated capacity S of the generator G ; The parameters of the single-machine infinite-bus equivalent power source include the per-unit value of the equivalent impedance Xs and the base capacity S B ; The transformer parameters include the percentage of short-circuit voltage U k %, and the rated capacity S of the transformer T ; The load parameters include the positive-sequence reactance X1, the per-unit value of the negative-sequence reactance X2, and the zero-sequence reactance X0, and the rated capacity S of the generator G .
3. The adaptive short-circuit current calculation method for the main wiring of a thermal power plant based on topological linkage according to claim 1, wherein, The building of the electrical main connection model for short-circuit calculation based on the component model parameter library described in Step 2 means constructing an electrical main connection model that adapts to the actual power plant's main connection according to the component model.
4. The adaptive short-circuit current calculation method for the main wiring of a thermal power plant based on topological linkage according to claim 1, characterized in that, In Step 3, formulating graph theory rules for different voltage levels in the electrical main connection model for short-circuit calculation means that when there are m generators and m main transformers operating in the grid-connected system S, define the node positions according to the voltage levels from high to low, and each node represents a different voltage level.
5. The adaptive short-circuit current calculation method for the main wiring of a thermal power plant based on topological linkage according to claim 4, wherein In Step 3, the method of searching for the shortest fault path with the ground potential as the target means taking one of the units as the power source, simulating faults at nodes with different voltage levels, treating other power sources as zero potential, and searching for the shortest path from the power source according to the ground potential search rules to form the short-circuit impedance.
6. The adaptive short-circuit current calculation method for the main wiring of a thermal power plant based on topological linkage according to claim 5, wherein, In step 3, the method of formulating graph theory rules for different voltage levels in the short-circuit calculation electrical main wiring model, searching for the shortest fault path with the ground potential as the target, forming short-circuit paths formed by the separate actions of different power supply points, forming a short-circuit impedance per-unit value sequence for each path component impedance, forming a short-circuit current per-unit value according to the short-circuit impedance per-unit value, and forming a short-circuit current nominal value according to the short-circuit current per-unit value means that each power supply point searches for the shortest fault path with the ground potential as the target to generate an equivalent reactance , repeating the above process to form a short-circuit impedance per-unit value P; （1） Form the per-unit value Q of the short-circuit current according to the per-unit value P of the short-circuit impedance according to Equation (2), where the constant K represents different types of short-circuit values, including three-phase short-circuit K = 1, two-phase short-circuit K = 1.732, and three-phase short-circuit K = 3; （2） The per-unit value Q of the short-circuit current forms the nominal value Q* of the short-circuit current according to Equation (3). In Equation (3), is the base capacity, and Uj is the base voltage at different voltage levels; （3）。 7. The adaptive short-circuit current calculation method for the main wiring of a thermal power plant based on topological linkage according to claim 6, wherein, In Step 4, storing and retrieving the short-circuit calculation result data according to the node definition rules based on the nominal value of the short-circuit current means storing the per-unit value sequence of the impedance calculated in Step 3 in ascending order of the unit rule number for the short-circuit calculation results, leaving a retrievable window; The formation of the short-circuit calculation result and having a human-computer interaction function means that the calculated results support export in the forms of xls, csv, and txt.
8. An adaptive short-circuit current calculation system for the main electrical connection of a thermal power plant based on topological linkage, characterized in that, including: A model parameter library establishment module that establishes a component model parameter library; A main connection model building module that builds an electrical main connection model for short-circuit calculation based on the component model parameter library; A first calculation module that formulates graph theory rules for different voltage levels in the electrical main connection model for short-circuit calculation, searches for the shortest fault path method with the ground potential as the target, forms short-circuit paths formed by the separate action of different power sources, forms the per-unit value sequence of the impedance of each path element into the per-unit value of the short-circuit impedance, forms the per-unit value of the short-circuit current according to the per-unit value of the short-circuit impedance, and forms the nominal value of the short-circuit current according to the per-unit value of the short-circuit current; A second calculation module that stores and retrieves the short-circuit calculation result data according to the node definition rules based on the nominal value of the short-circuit current, forms the short-circuit calculation result and has a human-computer interaction function.
9. The adaptive short-circuit current calculation system for the main electrical connection of a thermal power plant based on topological linkage according to claim 8, wherein The establishment of the component model parameter library in the model parameter library establishment module includes single-machine infinite equivalent power source parameters, generator parameters, transformer parameters, and load parameters; Among them, the generator parameters include the per-unit value of the subtransient reactance X d’’ , the per-unit value of the transient reactance X d , the synchronous reactance X d per-unit value, the per-unit value of the negative-sequence reactance X2, the per-unit value of the zero-sequence reactance X0, and the rated capacity S of the generator G ; The parameters of the single-machine infinite-bus equivalent power source include the per-unit value of the equivalent impedance Xs and the base capacity S B ; The parameters of the transformer include the percentage of short-circuit voltage U k %, and the rated capacity S of the transformer T ; The load parameters include the positive sequence reactance X1, the per-unit value of the negative sequence reactance X2, and the zero sequence reactance X0, and the rated capacity S of the generator G .
10. The adaptive short-circuit current calculation system for the main electrical connection of a thermal power plant based on topological linkage according to claim 8, wherein, In the main wiring model construction module, the construction of the short-circuit calculation electrical main wiring model based on the component model parameter library means constructing an electrical main wiring model adapted to the actual power plant's main wiring according to the component models.