A method for determining the feasibility of a power flow scheme for a power system

Abstract

This invention relates to the field of power system technology and discloses a method for feasibility assessment of power flow scheme groups in power systems. The method includes constructing a multi-dimensional quantitative criterion system, including constraints on dense corridors, the number of crossings, the total carrying capacity of the receiving end, the single-direction power receiving capacity of the receiving end, the simultaneous power transmission and receiving capacity of the receiving end, and the power transmission capacity of dense corridors in the region. It uses intelligent recognition algorithms to automatically count the number of crossings of transmission lines and automatically marks dense corridors. The feasibility assessment of power flow scheme groups is transformed into a constraint satisfaction problem, and batch parallel verification and scenario-based verification are performed based on this constraint satisfaction problem. A hierarchical calibration and dynamic correction method is adopted to clarify the engineering boundaries of each criterion. The advantages of this invention are that it forms a standardized assessment process, eliminates reliance on expert experience, and improves the objectivity and reusability of the assessment results.

Description

Technical Field

[0001] This invention relates to the field of power system technology, and in particular to a method for determining the feasibility of power flow schemes in a power system. Background Technology

[0002] Traditional power flow scheme feasibility assessments often focus on verifying the electrical performance of a single channel, primarily using single-dimensional criteria such as sending-end resource conditions, receiving-end market space, inter-provincial channel technical parameters, and institutional coordination. In terms of methodology, these assessments often employ manual item-by-item verification or simple rule matching. First, static calculations are performed on the total resources and output timing characteristics of the sending-end base. Then, the load acceptance capacity and voltage stability margin of the receiving-end grid are verified. Finally, the feasibility and economic benefits of the channel's construction are evaluated. This overall process lacks a systematic consideration of the multi-channel cluster coupling effect, geographical constraints, and dynamic operational risks.

[0003] The existing technology has the following drawbacks: First, traditional criteria only cover electrical safety and basic engineering conditions, failing to incorporate key non-electrical constraints such as the spatial capacity limitations of dense transmission corridors and the construction and maintenance risks associated with the number of transmission line crossings. This results in some schemes being unable to be implemented due to geographical conflicts or excessive construction difficulties. Second, the manual item-by-item verification method requires traversing all schemes and repeatedly performing power flow simulations when dealing with large-scale power flow schemes with multiple sending and receiving ends. This leads to an exponential increase in computational load, making it difficult to meet the timeliness requirements of engineering planning. Third, it does not consider the interlocking constraints of the grid's carrying capacity when multiple channels transmit power in parallel, nor the electromagnetic coupling risks of dense corridors. This can easily underestimate the impact of multiple lines being put into operation simultaneously on the stability of the receiving-end grid, resulting in significant deviations between the judgment results and actual operating conditions. Fourth, the quantitative standards for constraints such as dense corridors and crossings are unclear. Thresholds are set based on expert experience, lacking unified mathematical modeling and quantitative calculation methods, resulting in insufficient objectivity and reusability of the criteria. Summary of the Invention

[0004] The purpose of this invention is to overcome the shortcomings of the prior art and provide a method for determining the feasibility of power flow schemes in a power system.

[0005] The objective of this invention is achieved through the following technical solution: a method for determining the feasibility of power flow schemes in a power system, the method comprising the following steps:

[0006] S1. Construct a multi-dimensional quantitative judgment system, including dense corridor constraints, crossover frequency constraints, total carrying capacity constraints at the receiving end, single-direction power receiving capacity constraints at the receiving end, simultaneous power transmission and reception capacity constraints at the receiving end, and regional dense corridor power transmission capacity constraints.

[0007] S2. Based on intelligent recognition algorithms, automatically count the number of crossings of transmission lines and automatically mark dense corridors;

[0008] S3. Transform the feasibility judgment of the power flow scheme group into a constraint satisfaction problem, and perform batch parallel verification and scenario-based verification based on the constraint satisfaction problem;

[0009] S4. Employ a layered calibration and dynamic correction method to clarify the engineering boundaries of each criterion.

[0010] Specifically, the dense corridor constraint is as follows:

[0011] ;

[0012] In the formula, This represents the actual number of power transmission lines within the transmission corridor. This represents the maximum number of lines that can be accommodated for a given width.

[0013] The constraint on the number of crossovers is:

[0014] ;

[0015] In the formula, This represents the total number of line crossings in the plan; The maximum number of crossings allowed by engineering specifications;

[0016] The constraint on the total load capacity of the receiving end is:

[0017] ;

[0018] In the formula, This represents the total input power at the receiving end. This represents the maximum load-bearing capacity of the receiving end theory; This refers to the safety margin factor. Uncertainty deduction factor; Let be the input power of the i-th receiving end.

[0019] The constraint on the single-direction power carrying capacity of the receiving end is:

[0020] ;

[0021] In the formula, For the receiving end from the first Power received in the direction; This represents the maximum permissible input power in this direction;

[0022] The constraint on the scale of simultaneous sending and receiving at the receiving end is:

[0023] ;

[0024] In the formula, The input power at the receiving end; This refers to the output power at the receiving end. This represents the maximum permissible difference in power flow between the two directions.

[0025] The power supply capacity constraint of the dense corridor in the region is:

[0026] ;

[0027] In the formula, The carrying capacity index of the regional power transmission corridor; This represents the maximum allowable carrying capacity index required by regional planning and environmental protection standards.

[0028] Specifically, the automated counting of the number of crossings of transmission lines in S2 is as follows:

[0029] Each power flow path is discretized into an ordered sequence of coordinate points and then divided into continuous straight line segments, denoted as the set of line segments:

[0030] ;

[0031] In the formula, It is a single line segment, which consists of the coordinates of its two endpoints. and express;

[0032] The fast rejection test checks whether any two line segments intersect. and Construct its minimum enclosing rectangle. If the rectangles do not overlap, they are considered non-intersecting, as shown below:

[0033] ;

[0034] ;

[0035] For line segments that pass the fast rejection test, the cross product of vectors is used to determine whether they truly intersect. The cross product is calculated as follows:

[0036] ;

[0037] For line segments that are determined to intersect, the total number of intersections is accumulated.

[0038] Specifically, in S2, the automated marking of dense corridors is as follows:

[0039] The planning area is divided into areas with a resolution of [resolution value]. The regular grid has a total of:

[0040] ;

[0041] In the formula, , These represent the number of grid cells in the horizontal and vertical directions, respectively.

[0042] Calculate the total length of all lines within each grid:

[0043] ;

[0044] In the formula, For grid Total length of internal wiring; For the first The length of a line that falls within the grid; m is the total number of lines that fall within the grid.

[0045] Dense grid determination, setting a density threshold:

[0046] ;

[0047] In the formula, The average grid density; The standard deviation of density; This is the adjustment coefficient;

[0048] like If a grid is connected, it is marked as a dense grid, and connected dense grids form a dense corridor.

[0049] Specifically, the steps of S3 are as follows:

[0050] Input parameter definition:

[0051] Let the set of solutions be:

[0052] ;

[0053] The constraint set is:

[0054] ;

[0055] The scene set is as follows:

[0056] ;

[0057] For any scheme If a scenario exists , so that:

[0058] ;

[0059] If all conditions are met, the plan is deemed feasible; otherwise, it is not.

[0060] Divide the solution set into Each batch contains [number] batches, each batch containing [number] batches. One plan, denoted as... ( For each batch Parallel verification of constraint satisfaction for all solutions:

[0061] ;

[0062] In the formula, A set of feasible solutions; This is the m-th constraint.

[0063] Specifically, in S4, the dynamic correction method is used to clarify the engineering boundaries of each criterion as follows:

[0064] Introduce a correction factor:

[0065] ;

[0066] In the formula, This is a correction factor; Assess the strength of the regional power grid; Assess ecological sensitivity. , These are the weighting coefficients. ;

[0067] The corrected boundary values ​​are:

[0068] ;

[0069] ;

[0070] In the formula, This is the revised maximum number of acceptable lines; This represents the maximum bearing capacity of the modified receiving end theory.

[0071] The present invention has the following advantages:

[0072] This invention integrates electrical constraints with non-electrical constraints such as geospatial constraints and construction and maintenance constraints to form six quantitative criteria, covering the feasibility requirements of power flow schemes from planning to implementation. Based on the CSP framework, it realizes batch and automated verification of schemes. Combined with Monte Carlo sampling technology, it can complete the judgment of 10,000 sampled schemes in just a few hours, which is a thousand times more efficient than manual verification. Through intelligent identification and marking technology, it accurately captures coupling effects such as multi-channel intersections and electromagnetic coupling in dense corridors, avoiding the underestimation of cluster risks by traditional methods. It clarifies the mathematical expressions and engineering thresholds of various constraints, forms a standardized judgment process, eliminates the dependence on expert experience, and improves the objectivity and reusability of the judgment results. Attached Figure Description

[0073] Figure 1 This is a schematic diagram of the discrimination method of the present invention. Detailed Implementation

[0074] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only for explaining the invention and are not intended to limit the invention; that is, the described embodiments are merely some embodiments of the invention, and not all embodiments. The components of the embodiments of the invention described and shown in the accompanying drawings can generally be arranged and designed in various different configurations.

[0075] Therefore, the following detailed description of the embodiments of the invention provided in the accompanying drawings is not intended to limit the scope of the claimed invention, but merely to illustrate selected embodiments of the invention. All other embodiments obtained by those skilled in the art based on the embodiments of the invention without inventive effort are within the scope of protection of the invention.

[0076] It should be noted that relational terms such as "first" and "second" are used merely to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitation, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element.

[0077] The present invention will be further described below with reference to the accompanying drawings, but the scope of protection of the present invention is not limited to the following description.

[0078] like Figure 1 As shown, a method for determining the feasibility of power flow schemes in a power system includes the following steps:

[0079] S1. Construct a multi-dimensional quantitative judgment system, including dense corridor constraints, crossover frequency constraints, total carrying capacity constraints at the receiving end, single-direction power receiving capacity constraints at the receiving end, simultaneous power transmission and reception capacity constraints at the receiving end, and regional dense corridor power transmission capacity constraints.

[0080] The constraint of dense corridors limits the density of power transmission lines within the corridor to avoid electromagnetic interference and safety accidents. The criterion is as follows:

[0081] ;

[0082] In the formula, This represents the actual number of power transmission lines within the transmission corridor. This represents the maximum number of lines that can be accommodated for a given width, such as a corridor with a width ≤ 600m. Three ultra-high voltage direct current lines were selected;

[0083] Crossing and crossing frequency constraints control the number of grade-separated crossings of transmission lines, reducing construction and operation and maintenance risks. The criteria are as follows:

[0084] ;

[0085] In the formula, This represents the total number of line crossings in the plan; The maximum number of crossings allowed by engineering specifications (the maximum number of crossings allowed per channel in the planning year is 1).

[0086] The criteria for ensuring the safe acceptance of total input power by the receiving-end power grid, preventing overload and voltage collapse, are as follows:

[0087] ;

[0088] In the formula, This represents the total input power at the receiving end. This represents the maximum load-bearing capacity of the receiving end theory; The safety margin factor is set to 0.9; As an uncertainty reduction factor, it is set to 0.5, and the receiving end can receive a maximum of 1 DC transmission in a single planning period (5 years); Let be the input power of the i-th receiving end.

[0089] The unidirectional power receiving capacity of the receiving end is constrained, limiting the input power in one direction to avoid regional power grid imbalance. The criterion is as follows:

[0090] ;

[0091] In the formula, For the receiving end from the first Power received in the direction; This is the maximum allowable input power in this direction (determined by line capacity and stability analysis);

[0092] The system is subject to the same scale constraints on both the receiving and transmitting ends, and the carrying capacity under bidirectional power flow is constrained to ensure dynamic stability. The criterion is as follows:

[0093] ;

[0094] In the formula, The input power at the receiving end; This refers to the output power at the receiving end. This represents the maximum permissible difference in power flow between the two directions.

[0095] The power supply capacity constraints of densely populated corridors in the region are determined by the following criteria:

[0096] ;

[0097] In the formula, The carrying capacity index of the regional power transmission corridor; This represents the maximum allowable carrying capacity index required by regional planning and environmental protection standards.

[0098] S2. Based on intelligent recognition algorithms, automatically count the number of crossings of transmission lines and automatically mark dense corridors;

[0099] An intelligent recognition method combining line segment discretization and geometric intersection determination is adopted to automate the counting of intersection and crossing times. Specifically:

[0100] Path segmentation involves discretizing each power flow path into an ordered sequence of coordinate points and then breaking it down into continuous straight line segments, denoted as the line segment set.

[0101] ;

[0102] In the formula, It is a single line segment, which consists of the coordinates of its two endpoints. and express;

[0103] By using a fast rejection test to determine whether any two line segments intersect, for any two line segments... and Construct its minimum enclosing rectangle. If the rectangles do not overlap, they are considered non-intersecting, as shown below:

[0104] ;

[0105] ;

[0106] For line segments that pass the fast rejection test, the cross product of vectors is used to determine whether they truly intersect. The cross product is calculated as follows:

[0107] ;

[0108] If the above conditions are met, the line segments are determined to intersect, and the total number of intersections is accumulated.

[0109] Automated marking of dense corridors is achieved based on grid density analysis, specifically as follows:

[0110] The planning area is gridded, dividing the planning area into grids with a resolution of [resolution value missing]. The regular grid has a total of:

[0111] ;

[0112] In the formula, , These represent the number of grid cells in the horizontal and vertical directions, respectively.

[0113] Grid density calculation, calculating the total length of all lines within each grid:

[0114] ;

[0115] In the formula, For grid Total length of internal wiring; For the first The length of a line that falls within the grid; m is the total number of lines that fall within the grid.

[0116] Dense grid determination, setting a density threshold:

[0117] ;

[0118] In the formula, The average grid density; The standard deviation of density; The adjustment coefficient is set to 1.5.

[0119] like If a grid is connected, it is marked as a dense grid, and connected dense grids form a dense corridor.

[0120] S3. The feasibility assessment of the power flow scheme group is transformed into a constraint satisfaction problem, and batch parallel verification and scenario-based verification are performed based on the constraint satisfaction problem; the scheme group assessment is transformed into a constraint satisfaction problem, and efficient screening is achieved through batch parallel verification + scenario-based constraint verification, specifically:

[0121] Input parameter definition:

[0122] Let the set of solutions be:

[0123] ;

[0124] The constraint set is:

[0125] ;

[0126] in, Corresponding to dense corridor constraints; Corresponding crossover / span constraint; Corresponding to the total carrying capacity constraint of the receiving end; Constraints on the power carrying capacity of a single direction at the receiving end; The corresponding receiving end is subject to the same scale constraint; Power supply capacity constraints in densely populated corridors in the corresponding area.

[0127] The scene set is as follows:

[0128] ;

[0129] Constraints satisfy the decision logic for any solution If a scenario exists , so that:

[0130] ;

[0131] If all conditions are met, the plan is deemed feasible; otherwise, it is not. Corresponding to dense corridor constraints; Corresponding crossover / span constraint; Corresponding to the total carrying capacity constraint of the receiving end; Constraints on the power carrying capacity of a single direction at the receiving end; The corresponding receiving end is subject to the same scale constraint; Power supply capacity constraints in densely populated corridors in the corresponding area; This is the i-th solution; For the set of all solutions, For the j-th scene; For all scene sets; This represents the actual number of power transmission lines within the transmission corridor. This represents the maximum number of lines that can be accommodated for a given width, such as a corridor with a width ≤ 600m. Take 3 ultra-high voltage direct current lines; This represents the total number of line crossings in the plan; The maximum number of crossings allowed by engineering specifications (the maximum number of crossings allowed per channel in the planning year is 1). The maximum allowable input power for this direction (determined by line capacity and stability analysis); The input power at the receiving end; This refers to the output power at the receiving end. The carrying capacity index of the regional power transmission corridor; The maximum allowable carrying capacity index for regional planning and environmental protection requirements; , These are the input power for the l-th and k-th lines, respectively; The safety margin factor is set to 0.9; The uncertainty reduction factor is set to 0.5.

[0132] Batch parallel acceleration logic divides the solution set into... Each batch contains [number] batches, each batch containing [number] batches. One plan, denoted as... ( For each batch Parallel verification of constraint satisfaction for all solutions:

[0133] ;

[0134] In the formula, A set of feasible solutions; This is the m-th constraint.

[0135] S4. Employ a layered calibration and dynamic correction method to clarify the engineering boundaries of each criterion.

[0136] Layered calibration: Combining engineering specifications and regional characteristics, the planning unit determines the initial boundary values ​​based on experience and historical data, such as:

[0137] Dense corridors: corridors with a width of ≤600m, Return to ultra-high voltage direct current;

[0138] Receiving end capacity: Based on the regional power shortage, the Beijing-Tianjin-Hebei region and Shandong province can receive one DC transmission line;

[0139] Crossing over: .

[0140] The planning unit shall determine this based on experience and historical circumstances.

[0141] The engineering boundaries of each criterion are defined using a dynamic correction method:

[0142] Introduce a correction factor:

[0143] ;

[0144] In the formula, This is a correction factor; Assess the strength of the regional power grid; Assess ecological sensitivity. , These are the weighting coefficients. ;

[0145] The corrected boundary values ​​are:

[0146] ;

[0147] ;

[0148] In the formula, This is the revised maximum number of acceptable lines; This represents the maximum bearing capacity of the modified receiving end theory.

[0149] The above description is merely a preferred embodiment of the present invention and does not constitute any limitation on the present invention. Any person skilled in the art can make many possible variations and modifications to the technical solution of the present invention, or modify it into equivalent embodiments, without departing from the scope of the present invention. Therefore, any modifications, equivalent changes, and alterations made to the above embodiments based on the technology of the present invention without departing from the scope of the present invention are within the protection scope of the present invention.

Claims

1. A method for determining the feasibility of power flow schemes in a power system, characterized in that: The method includes the following steps: S1. Construct a multi-dimensional quantitative judgment system, including dense corridor constraints, crossover frequency constraints, total carrying capacity constraints at the receiving end, single-direction power receiving capacity constraints at the receiving end, simultaneous power transmission and reception capacity constraints at the receiving end, and regional dense corridor power transmission capacity constraints. S2. Based on intelligent recognition algorithms, automatically count the number of crossings of transmission lines and automatically mark dense corridors; S3. Transform the feasibility judgment of the power flow scheme group into a constraint satisfaction problem, and perform batch parallel verification and scenario-based verification based on the constraint satisfaction problem; S4. Employ a layered calibration and dynamic correction method to clarify the engineering boundaries of each criterion.

2. The method for determining the feasibility of power flow schemes in a power system according to claim 1, characterized in that: The dense corridor constraint is: ； In the formula, This represents the actual number of power transmission lines within the transmission corridor. This represents the maximum number of lines that can be accommodated for a given width. The constraint on the number of crossovers is: ； In the formula, This represents the total number of line crossings in the plan; The maximum number of crossings allowed by engineering specifications; The constraint on the total load capacity of the receiving end is: ； In the formula, This represents the total input power at the receiving end. The input power is the i-th receiving end; This represents the maximum load-bearing capacity of the receiving end theory; This refers to the safety margin factor. Uncertainty deduction factor; The constraint on the single-direction power carrying capacity of the receiving end is: ； In the formula, For the receiving end from the first Power received in the direction; This represents the maximum permissible input power in this direction; The scale constraint for simultaneous sending and receiving at the receiving end is: ； In the formula, This refers to the input power at the receiving end. This refers to the output power at the receiving end. This represents the maximum permissible difference in power flow between the two directions. The power supply capacity constraint of the dense corridor in the region is: ； In the formula, The carrying capacity index of the regional power transmission corridor; This represents the maximum allowable carrying capacity index required by regional planning and environmental protection standards.

3. The method for determining the feasibility of power flow schemes in a power system according to claim 1, characterized in that: The automated counting of the number of crossings of transmission lines in S2 is as follows: Each power flow path is discretized into an ordered sequence of coordinate points and then divided into continuous straight line segments, denoted as the set of line segments: ； In the formula, It is a single line segment, which consists of the coordinates of its two endpoints. and express; The fast rejection test checks whether any two line segments intersect. and Construct its minimum enclosing rectangle. If the rectangles do not overlap, they are considered non-intersecting, as shown below: ； ； For line segments that pass the fast rejection test, the cross product of vectors is used to determine whether they truly intersect. The cross product is calculated as follows: ； For line segments that are determined to intersect, the total number of intersections is accumulated.

4. The method for determining the feasibility of power flow schemes in a power system according to claim 1, characterized in that: In S2, the dense corridors are automatically marked as follows: The planning area is divided into areas with a resolution of [resolution value]. The regular grid has a total of: ； In the formula, , These represent the number of grid cells in the horizontal and vertical directions, respectively. Calculate the total length of all lines within each grid: ； In the formula, For grid Total length of internal wiring; For the first The length of a line that falls within the grid; m is the total number of lines that fall within the grid. Dense grid determination, setting a density threshold: ； In the formula, The average grid density; The standard deviation of density; This is the adjustment coefficient; like If a grid is connected, it is marked as a dense grid, and connected dense grids form a dense corridor.

5. The method for feasibility determination of power system power flow schemes according to claim 1, characterized in that: The specific steps of S3 are as follows: Input parameter definition: Let the set of solutions be: ； In the formula, This is the i-th solution; For the set of all solutions; The constraint set is: ； In the formula, Corresponding to dense corridor constraints; Corresponding crossover / span constraint; Corresponding to the total carrying capacity constraint of the receiving end; Constraints on the power carrying capacity of a single direction at the receiving end; The corresponding receiving end is subject to the same scale constraint; Power supply capacity constraints in densely populated corridors in the corresponding area; The scene set is as follows: ； In the formula, For the j-th scene; For all scene sets; For any scheme If a scenario exists , so that: ； In the formula, This represents the actual number of power transmission lines within the transmission corridor. This represents the maximum number of lines that can be accommodated for a given width. This represents the total number of line crossings in the plan; The maximum number of crossings allowed by engineering specifications; This is the maximum permissible input power. This refers to the input power at the receiving end. This refers to the output power at the receiving end. The carrying capacity index of the regional power transmission corridor; The maximum allowable carrying capacity index for regional planning and environmental protection requirements; , These are the input power for the l-th and k-th lines, respectively; This refers to the safety margin factor. Uncertainty deduction factor; If all conditions are met, the plan is deemed feasible. Otherwise, it is not feasible; Divide the solution set into Each batch contains [number] batches, each batch containing [number] batches. One plan, denoted as... ( For each batch Parallel verification of constraint satisfaction for all solutions: ； In the formula, A set of feasible solutions; This is the m-th constraint.

6. The method for feasibility determination of power flow schemes in a power system according to claim 1, characterized in that: The dynamic correction method used in S4 clarifies the engineering boundaries of each criterion as follows: Introduce a correction factor: ； In the formula, This is a correction factor; Assess the strength of the regional power grid; Assess ecological sensitivity. , These are the weighting coefficients. ; The corrected boundary values ​​are: ； ； In the formula, This is the revised maximum number of acceptable lines; This represents the maximum bearing capacity of the modified receiving end theory.

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