A method and system for calculating longitudinal multi-section tidal current adjustment and thermal stability limit

Abstract

The present invention discloses a method and system for calculating the thermal stability limit of longitudinal multi-section power flow adjustment. The method comprises: calculating the sensitivity of each generator and load to section power based on online power flow data, and calculating the sensitivity based on determining the line with the lowest thermal stability margin before each round of power flow adjustment; grouping the generators in the relevant area of ​​the longitudinal section according to the sensitivity to obtain a section margin release group, a section power balance group, a section blocked group, and a regional power balance group; optimizing the output of the blocked section group, taking the maximum total maximum output capacity of the blocked group as the optimization goal and the maximum load rate section not exceeding the limit as the boundary condition, estimating the output of the generators in the blocked section group, and obtaining the output of the generators of the blocked group; and automatically adjusting and generating the target power flow of the power grid based on the output of the generators of the blocked group using a multi-section power flow control algorithm.

Description

Technical Field

[0001] The present invention relates to the field of large power grid online safety analysis, and more specifically, to a method and system for longitudinal multi-section power flow adjustment and thermal stability limit calculation. Background Art

[0002] With the large-scale integration of intermittent renewable energy, the post-N-1 thermal stability issue during periods of rapid renewable energy generation or peak loads is severely restricting the power transmission capacity of key sections or channels in the power grid. For complex channels with multiple longitudinally coupled sections, the current dispatching automation system's thermal stability limit function is unable to calculate the post-fault thermal stability limit. Dispatchers must rely on their experience to determine the section's transmission capacity and determine control measures. Summary of the Invention

[0003] According to the present invention, a method and system for longitudinal multi-section flow adjustment and thermal stability limit calculation are provided to solve the technical problem that the thermal stability limit-related functions in the current dispatching automation system cannot calculate the thermal stability limit after a failure, and can only rely on the dispatcher's experience to judge the section transportation capacity and determine the control means.

[0004] According to a first aspect of the present invention, a method for longitudinal multi-section tidal flow adjustment and thermal stability limit calculation is provided, comprising:

[0005] Read the state estimation data and offline operation mode data in the power grid intelligent dispatching system and integrate them to obtain online power flow data;

[0006] Based on online power flow data, calculate the sensitivity of each generator and load to the section power. Before each round of power flow adjustment, determine the line with the lowest thermal stability margin and calculate the sensitivity.

[0007] According to the sensitivity, the generators in the relevant area of ​​the longitudinal section are grouped to obtain the section margin release group, the section power balance group, the section blocked group and the regional power balance group;

[0008] Considering optimizing the output of the blocked group in the section, taking the maximum total output capacity of the blocked group as the optimization goal and the maximum load rate section not exceeding the limit as the boundary condition, the generator output in the blocked group in the section is estimated to obtain the generator output of the blocked group;

[0009] Based on the output of the blocked generators, a multi-section control power flow algorithm is used to automatically adjust and generate the target power flow of the power grid;

[0010] Perform thermal stability check on each section after N-1 faults, and output the thermal stability limit of the longitudinal multi-section and the corresponding generator output.

[0011] Optionally, based on online power flow data, the sensitivity of each generator and load to the section power is calculated. The sensitivity is calculated based on the line with the lowest thermal stability margin determined before each round of power flow adjustment, including:

[0012] Perform sensitivity analysis on the generators in the sending and receiving areas of the section to determine the generator adjustment order under the N-1 thermal stability constraint. Before each round of power flow adjustment, determine the line with the lowest thermal stability margin and calculate the sensitivity:

[0013]

[0014] Where K im is the sensitivity of generator m to section i, calculated according to formula (2).

[0015]

[0016] Where, i is the set of all lines in section i.

[0017] Optionally, consider optimizing the output of the blocked section group, taking the maximum total output capacity of the blocked group as the optimization goal, and taking the maximum load rate section not exceeding the limit as the boundary condition, and estimate the generator output of the blocked section group to obtain the generator output of the blocked group, including:

[0018] Estimate the section power according to the sensitivity until a section among the multiple sections reaches the preset target power P T , or all units reach their upper limit, the maximum output of the blocked units can be calculated according to the following optimization model, with the boundary condition that the section power reaches the preset power P T 2. The unit output does not exceed the line:

[0019]

[0020] Where K im is the sensitivity of generator m to section i, P sec0 is the initial power of the section, P m0 is the initial power of generator i, P max_m and P min_m are the upper and lower power limits of generator m respectively.

[0021] Optionally, based on the output of the blocked generators, a multi-section control power flow algorithm is used to automatically adjust and generate the target power flow of the power grid, including:

[0022] Add the section active power deviation equation to the Newton method power flow equation:

[0023]

[0024] Where ΔPseti is the active power deviation of section j, is the active power of section j, which is composed of N j The active power of the lines is added together to get P des_i is the active power target value of the section;

[0025] The active power P of the mth machine in the kth control group g (m) is:

[0026] P g (m) = f p (m)+α(k)ΔP vail (m) (5)

[0027] Where, f p (m) is the topological constraint of the generator node, α(k) is the active power control factor of group k, ΔP vail (m) is the weighted active adjustable output of the generator;

[0028] The active power expression of the distributed balancing machine is the same as that of formula (5). It and the section power control machine are collectively referred to as the control unit. A phase reference equation is added to each electrical island. If the m machines in the electrical island l are the phase reference, then:

[0029] θ m =θ 0l (6)

[0030] Where θ m is the phase angle of the mth machine, θ 0l The phase angle reference set for electrical island l is taken as 0.

[0031] Optionally, perform thermal stability check on each section after N-1 faults, and output the thermal stability limits of the longitudinal multi-sections and the corresponding generator output, including:

[0032] After the section flow adjustment is completed, perform thermal stability check on each section after N-1 faults:

[0033] If a section exceeds the limit or is overloaded, the thermal stability auxiliary decision-making program will be called to ensure that all sections are within the limit, and the thermal stability limit of the longitudinal multi-section and the corresponding generator output will be output;

[0034] If there is no section exceeding the limit or overloading, each control section in the channel will be increased at the same time according to the predetermined step size. The increased power of each control section can be distributed according to the proportion of the maximum current carrying capacity of the line. The section configuration and the adjustment group configuration remain unchanged. After the adjustment, the section thermal stability check is performed. If there is still no section exceeding the limit or overloading, continue to increase the section power according to the step size until the section exceeds the limit and is overloaded. Call the thermal stability auxiliary decision-making program to ensure that all sections are within the limit, and output the thermal stability limit of the longitudinal multi-section and the corresponding generator output.

[0035] According to another aspect of the present invention, there is also provided a longitudinal multi-section tidal flow adjustment and thermal stability limit calculation system, comprising:

[0036] A data integration unit is used to read the state estimation data and offline operation mode data in the power grid intelligent dispatching system and integrate them to obtain online power flow data;

[0037] The sensitivity calculation unit is used to calculate the sensitivity of each generator and load to the section power based on the online power flow data, and to calculate the sensitivity based on the line with the lowest thermal stability margin determined before each round of power flow adjustment;

[0038] An adjustable equipment selection unit is used to group the generators in the relevant area of ​​the longitudinal section according to the sensitivity to obtain the section margin release group, the section power balance group, the section blocked group and the regional power balance group;

[0039] The adjustable equipment power estimation unit is used to optimize the output of the blocked group in the section, taking the maximum total output capacity of the blocked group as the optimization goal and the maximum load rate section not exceeding the limit as the boundary condition, to estimate the output of the generators in the blocked group in the section, and obtain the output of the generators in the blocked group;

[0040] The multi-section power flow adjustment unit is used to automatically adjust and generate the target power flow of the power grid based on the output of the blocked generator group using the multi-section power flow control algorithm;

[0041] The thermal stability limit calculation unit is used to check the thermal stability of each section after N-1 faults, and output the thermal stability limits of the longitudinal multi-sections and the corresponding generator output.

[0042] Optionally, the sensitivity calculation unit includes:

[0043] The sensitivity calculation subunit is used to perform sensitivity analysis on the generators in the sending and receiving areas of the section, determine the generator adjustment order under the N-1 thermal stability constraint, determine the line with the lowest thermal stability margin before each round of power flow adjustment, and calculate the sensitivity:

[0044]

[0045] Where K imis the sensitivity of generator m to section i, calculated according to formula (2).

[0046]

[0047] Where, i is the set of all lines in section i.

[0048] Optionally, the adjustable device power estimation unit includes:

[0049] The adjustable equipment power estimation subunit is used to estimate the section power according to the sensitivity until a section among multiple sections reaches the preset target power P T , or all units reach their upper limit, the maximum output of the blocked units can be calculated according to the following optimization model, with the boundary condition that the section power reaches the preset power P T 2. The unit output does not exceed the line:

[0050]

[0051] Where K im is the sensitivity of generator m to section i, P sec0 is the initial power of the section, P m0 is the initial power of generator i, P max_m and P min_m are the upper and lower power limits of generator m respectively.

[0052] Optionally, the multi-section flow adjustment unit includes:

[0053] The multi-section power flow adjustment subunit is used to add the section active power deviation equation to the Newton method power flow equation:

[0054]

[0055] Where ΔP seti is the active power deviation of section j, is the active power of section j, which is composed of N j The active power of the lines is added together to get P des_i is the active power target value of the section;

[0056] The active power P of the mth machine in the kth control group g (m) is:

[0057] P g (m) = f p (m)+α(k)ΔP vail (m) (5)

[0058] Where, f p(m) is the topological constraint of the generator node, α(k) is the active power control factor of group k, ΔP vail (m) is the weighted active adjustable output of the generator;

[0059] The active power expression of the distributed balancing machine is the same as that of formula (5). It and the section power control machine are collectively referred to as the control unit. A phase reference equation is added to each electrical island. If the m machines in the electrical island l are the phase reference, then:

[0060] θ m =θ 0l (6)

[0061] Where θ m is the phase angle of the mth machine, θ 0l The phase angle reference set for electrical island l is taken as 0.

[0062] Optionally, the thermal stability limit calculation unit includes:

[0063] The thermal stability check subunit is used to check the thermal stability of each section after N-1 faults after the section flow adjustment is completed:

[0064] The first output generator output sub-unit is used to call the thermal stability auxiliary decision-making program if there is an over-limit or overload in the section to ensure that all sections are within the limit, and output the thermal stability limit of the longitudinal multi-section and the corresponding generator output;

[0065] The second output generator output sub-unit is used to simultaneously increase the control sections in the channel according to the predetermined step size if there is no section exceeding the limit or overload. The increased power of each control section can be distributed according to the proportion of the maximum current carrying capacity of the line. The section configuration and the adjustment group configuration remain unchanged. After the adjustment, the section thermal stability check is performed. If there is still no exceeding the limit or overload, the section power is continued to be increased according to the step size until the section exceeds the limit and is overloaded. The thermal stability auxiliary decision-making program is called to ensure that all sections are within the limit, and the thermal stability limit of the longitudinal multi-section and the corresponding generator output are output.

[0066] This method enables the adjustment of longitudinal multi-section power flows to minimize power generation obstruction and online calculation of thermal stability limits, ensuring the safety of the calculated results while improving the power generation capacity of the obstructed generators. Furthermore, applying this method to online safety analysis ensures the continuity of the calculated results, reflecting the characteristics of the power grid and capturing changes in its operation. BRIEF DESCRIPTION OF THE DRAWINGS

[0067] A more complete understanding of exemplary embodiments of the present invention may be obtained by referring to the following drawings:

[0068] Figure 1This is a flow chart of a method for longitudinal multi-section tidal flow adjustment and thermal stability limit calculation according to this embodiment;

[0069] Figure 2 This is a schematic diagram of a method for calculating longitudinal multi-section tidal current adjustment and thermal stability limit according to this embodiment;

[0070] Figure 3 This is a schematic diagram of a longitudinal multi-section tidal flow adjustment and thermal stability limit calculation system described in this embodiment. DETAILED DESCRIPTION

[0071] Exemplary embodiments of the present invention will now be described with reference to the accompanying drawings. However, the present invention may be embodied in many different forms and is not limited to the embodiments described herein. These embodiments are provided to provide a thorough and complete disclosure of the present invention and to fully convey the scope of the present invention to those skilled in the art. The terminology used in the exemplary embodiments shown in the accompanying drawings is not intended to limit the present invention. In the accompanying drawings, identical elements are denoted by the same reference numerals.

[0072] Unless otherwise specified, the terms used herein (including technical terms) have the meanings commonly understood by those skilled in the art. In addition, it is understood that terms defined in commonly used dictionaries should be understood to have the same meanings as those in the context of the relevant fields, and should not be understood as idealized or overly formal meanings.

[0073] According to a first aspect of the present invention, a method 100 for calculating longitudinal multi-section tidal current adjustment and thermal stability limit is provided. Figure 1 As shown, the method 100 includes:

[0074] S101: Reading state estimation data and offline operation mode data in the power grid intelligent dispatching system, and integrating them to obtain online power flow data;

[0075] S102: Based on the online power flow data, calculate the sensitivity of each generator and load to the section power, and calculate the sensitivity based on the line with the lowest thermal stability margin determined before each round of power flow adjustment;

[0076] S103: Grouping the generators in the relevant area of ​​the longitudinal section according to the sensitivity to obtain a section margin release group, a section power balance group, a section blocked group, and a regional power balance group;

[0077] S104: Consider optimizing the output of the blocked generator group, taking the maximum total output capacity of the blocked generator group as the optimization goal, and taking the maximum load rate section not exceeding the limit as the boundary condition, estimating the output of the generators in the blocked generator group, and obtaining the generator output of the blocked generator group;

[0078] S105: Based on the output of the generators of the blocked group, a multi-section power flow control algorithm is used to automatically adjust and generate a target power flow of the power grid;

[0079] S106: Perform thermal stability check on each section after N-1 faults, and output the thermal stability limit of the longitudinal multi-section and the corresponding generator output.

[0080] Specifically, the cross-section power growth model employs an increase in power generation at the sending end and a decrease at the receiving end. The validity period for online transmission limit calculations is typically approximately 5-15 minutes. For most power grids, load fluctuations during this period are minimal. Therefore, a cross-section power growth model employs an increase in power generation at the sending end and a decrease at the receiving end.

[0081] Conduct sensitivity analysis on the generators in the sending and receiving areas of the cross-section to determine the generator adjustment order under the N-1 thermal stability constraint. Before each round of power flow adjustment, determine the line with the lowest thermal stability margin and calculate the sensitivity. The calculation formula is as follows:

[0082]

[0083] Where K im is the sensitivity of generator m to section i, calculated according to formula (2).

[0084]

[0085] Where, i is the set of all lines in section i.

[0086] Based on the sensitivity analysis results, the generators in the relevant areas of the longitudinal section are grouped into the following four groups:

[0087] Section margin release group: for the line with the lowest thermal stability margin in multiple sections, it is negative;

[0088] Section power balance group: Different sensitivity to each section

[0089] Section-blocked aircraft group: The sensitivity to all three sections is positive and relatively high.

[0090] Regional power balancing group: less sensitive to multiple sections.

[0091] Consider optimizing the output of the blocked section group, taking the maximum total output capacity of the blocked group as the optimization goal, and taking the section with the highest load rate not exceeding the limit as the boundary condition, to estimate the output of the generators in the blocked section group. Adjust the output of the blocked group, and estimate the section power according to the sensitivity until one of the multiple sections reaches the preset target power PT, or the output of all units reaches the upper limit. The maximum output that can be increased by the blocked unit can be calculated according to the following optimization model, with the boundary condition that the section power reaches the preset power P T , the unit output does not exceed the line.

[0092]

[0093] Where K im is the sensitivity of generator m to section i, P sec0 is the initial power of the section, P m0 is the initial power of generator i, P max_m and P min_m are the upper and lower power limits of generator m respectively.

[0094] Combined with the estimated generator output of the blocked group, a multi-section control power flow algorithm is used to automatically adjust and generate the target power flow for the grid. The core concept of the multi-section control method is to transform the traditional power flow equations to control the power of multiple sections using a specified generator group. First, the section active power deviation equation is added to the Newton method power flow equation.

[0095]

[0096] Where ΔP seti is the active power deviation of section j. is the active power of section j, which is composed of N j The active power of the lines is added together. des_i is the target active power value of the section.

[0097] The control effect of the generator is reflected by adding a power term to the power equation of the control unit. The active power P of the mth machine in the kth control group is g (m) is:

[0098] P g (m) = f p (m)+α(k)ΔP vail (m) (5)

[0099] Where, f p (m) is the topological constraint of the generator node, which is consistent with the traditional power flow equation. α(k) is the active power control factor of group k. ΔP vail (m) is the weighted active adjustable output of the generator.

[0100] Changes in cross-section power increase the unbalanced power in the power grid. This requires multiple units in the balancing group to share the unbalanced power, a method known as the distributed balancing machine algorithm. The active power expression of the distributed balancing machine is the same as equation (5). Together with the cross-section power control machine, it is collectively referred to as the control unit. A phase reference equation is added to each electrical island. If the m units in electrical island l are the phase reference, then:

[0101] θ m =θ 0l (6)

[0102] Where θ m is the phase angle of the mth machine. 0l The phase angle reference set for the electrical island l is usually taken as 0.

[0103] This method enables the adjustment of longitudinal multi-section power flows to minimize power generation obstruction and online calculation of thermal stability limits, ensuring the safety of the calculated results while improving the power generation capacity of the obstructed generators. Furthermore, applying this method to online safety analysis ensures the continuity of the calculated results, reflecting the characteristics of the power grid and capturing changes in its operation.

[0104] Optionally, based on online power flow data, the sensitivity of each generator and load to the section power is calculated. The sensitivity is calculated based on the line with the lowest thermal stability margin determined before each round of power flow adjustment, including:

[0105] Perform sensitivity analysis on the generators in the sending and receiving areas of the section to determine the generator adjustment order under the N-1 thermal stability constraint. Before each round of power flow adjustment, determine the line with the lowest thermal stability margin and calculate the sensitivity:

[0106]

[0107] Where K im is the sensitivity of generator m to section i, calculated according to formula (2).

[0108]

[0109] Where, i is the set of all lines in section i.

[0110] Optionally, consider optimizing the output of the blocked section group, taking the maximum total output capacity of the blocked group as the optimization goal, and taking the maximum load rate section not exceeding the limit as the boundary condition, and estimate the generator output of the blocked section group to obtain the generator output of the blocked group, including:

[0111] Estimate the section power according to the sensitivity until a section among the multiple sections reaches the preset target power P T, or all units reach their upper limit, the maximum output of the blocked units can be calculated according to the following optimization model, with the boundary condition that the section power reaches the preset power P T 2. The unit output does not exceed the line:

[0112]

[0113] Where K im is the sensitivity of generator m to section i, P sec0 is the initial power of the section, P m0 is the initial power of generator i, P max_m and P min_m are the upper and lower power limits of generator m respectively.

[0114] Optionally, based on the output of the blocked generators, a multi-section control power flow algorithm is used to automatically adjust and generate the target power flow of the power grid, including:

[0115] Add the section active power deviation equation to the Newton method power flow equation:

[0116]

[0117] Where ΔP seti is the active power deviation of section j, is the active power of section j, which is composed of N j The active power of the lines is added together to get P des_i is the active power target value of the section;

[0118] The active power P of the mth machine in the kth control group g (m) is:

[0119] P g (m) = f p (m)+α(k)ΔP vail (m) (5)

[0120] Where, f p (m) is the topological constraint of the generator node, α(k) is the active power control factor of group k, ΔP vail (m) is the weighted active adjustable output of the generator;

[0121] The active power expression of the distributed balancing machine is the same as that of formula (5). It and the section power control machine are collectively referred to as the control unit. A phase reference equation is added to each electrical island. If the m machines in the electrical island l are the phase reference, then:

[0122] θ m =θ 0l (6)

[0123] Where θ m is the phase angle of the mth machine, θ 0l The phase angle reference set for electrical island l is taken as 0.

[0124] Optionally, perform thermal stability check on each section after N-1 faults, and output the thermal stability limits of the longitudinal multi-sections and the corresponding generator output, including:

[0125] After the section flow adjustment is completed, perform thermal stability check on each section after N-1 faults:

[0126] If a section exceeds the limit or is overloaded, the thermal stability auxiliary decision-making program will be called to ensure that all sections are within the limit, and the thermal stability limit of the longitudinal multi-section and the corresponding generator output will be output;

[0127] If there is no section exceeding the limit or overloading, each control section in the channel will be increased at the same time according to the predetermined step size. The increased power of each control section can be distributed according to the proportion of the maximum current carrying capacity of the line. The section configuration and the adjustment group configuration remain unchanged. After the adjustment, the section thermal stability check is performed. If there is still no section exceeding the limit or overloading, continue to increase the section power according to the step size until the section exceeds the limit and is overloaded. Call the thermal stability auxiliary decision-making program to ensure that all sections are within the limit, and output the thermal stability limit of the longitudinal multi-section and the corresponding generator output.

[0128] This method enables the adjustment of longitudinal multi-section power flows to minimize power generation obstruction and online calculation of thermal stability limits, ensuring the safety of the calculated results while improving the power generation capacity of the obstructed generators. Furthermore, applying this method to online safety analysis ensures the continuity of the calculated results, reflecting the characteristics of the power grid and capturing changes in its operation.

[0129] According to another aspect of the present invention, a longitudinal multi-section tidal current adjustment and thermal stability limit calculation system 300 is provided. Figure 3 As shown, the system 300 includes:

[0130] The data integration unit 310 is used to read the state estimation data and offline operation mode data in the power grid intelligent dispatching system and integrate them to obtain online power flow data;

[0131] The sensitivity calculation unit 320 is used to calculate the sensitivity of each generator and load to the section power based on the online power flow data, and calculate the sensitivity based on the line with the lowest thermal stability margin determined before each round of power flow adjustment;

[0132] The adjustable device selection unit 330 is configured to group the generators in the relevant area of ​​the longitudinal section according to the sensitivity, and obtain the section margin release group, the section power balance group, the section blocked group, and the regional power balance group;

[0133] The adjustable equipment power estimation unit 340 is configured to optimize the output of the blocked generator group, taking the maximum total output capacity of the blocked generator group as the optimization goal and the maximum load rate section not exceeding the limit as the boundary condition, and estimate the generator output of the blocked generator group to obtain the generator output of the blocked generator group;

[0134] The multi-section power flow adjustment unit 350 is used to automatically adjust and generate the target power flow of the power grid based on the output of the generators of the blocked group using the multi-section power flow control algorithm;

[0135] The thermal stability limit calculation unit 360 is used to check the thermal stability of each section after N-1 faults, and output the thermal stability limit of the longitudinal multi-section and the corresponding generator output.

[0136] Optionally, the sensitivity calculation unit includes:

[0137] The sensitivity calculation subunit is used to perform sensitivity analysis on the generators in the sending and receiving areas of the section, determine the generator adjustment order under the N-1 thermal stability constraint, determine the line with the lowest thermal stability margin before each round of power flow adjustment, and calculate the sensitivity:

[0138]

[0139] Where K im is the sensitivity of generator m to section i, calculated according to formula (2).

[0140]

[0141] Where, i is the set of all lines in section i.

[0142] Optionally, the adjustable device power estimation unit includes:

[0143] The adjustable equipment power estimation subunit is used to estimate the section power according to the sensitivity until a section among multiple sections reaches the preset target power P T , or all units reach their upper limit, the maximum output of the blocked units can be calculated according to the following optimization model, with the boundary condition that the section power reaches the preset power P T 2. The unit output does not exceed the line:

[0144]

[0145] Where K im is the sensitivity of generator m to section i, P sec0 is the initial power of the section, P m0 is the initial power of generator i, P max_m and P min_mare the upper and lower power limits of generator m respectively.

[0146] Optionally, the multi-section flow adjustment unit includes:

[0147] The multi-section power flow adjustment subunit is used to add the section active power deviation equation to the Newton method power flow equation:

[0148]

[0149] Where ΔP seti is the active power deviation of section j, is the active power of section j, which is composed of N j The active power of the lines is added together to get P des_i is the active power target value of the section;

[0150] The active power P of the mth machine in the kth control group g (m) is:

[0151] P g (m) = f p (m)+α(k)ΔP vail (m) (5)

[0152] Where, f p (m) is the topological constraint of the generator node, α(k) is the active power control factor of group k, ΔP vail (m) is the weighted active adjustable output of the generator;

[0153] The active power expression of the distributed balancing machine is the same as that of formula (5). It and the section power control machine are collectively referred to as the control unit. A phase reference equation is added to each electrical island. If the m machines in the electrical island l are the phase reference, then:

[0154] θ m =θ 0l (6)

[0155] Where θ m is the phase angle of the mth machine, θ 0l The phase angle reference set for electrical island l is taken as 0.

[0156] Optionally, the thermal stability limit calculation unit includes:

[0157] The thermal stability check subunit is used to check the thermal stability of each section after N-1 faults after the section flow adjustment is completed:

[0158] The first output generator output sub-unit is used to call the thermal stability auxiliary decision-making program if there is an over-limit or overload in the section to ensure that all sections are within the limit, and output the thermal stability limit of the longitudinal multi-section and the corresponding generator output;

[0159] The second output generator output sub-unit is used to simultaneously increase the control sections in the channel according to the predetermined step size if there is no section exceeding the limit or overload. The increased power of each control section can be distributed according to the proportion of the maximum current carrying capacity of the line. The section configuration and the adjustment group configuration remain unchanged. After the adjustment, the section thermal stability check is performed. If there is still no exceeding the limit or overload, the section power is continued to be increased according to the step size until the section exceeds the limit and is overloaded. The thermal stability auxiliary decision-making program is called to ensure that all sections are within the limit, and the thermal stability limit of the longitudinal multi-section and the corresponding generator output are output.

[0160] A longitudinal multi-section power flow adjustment and thermal stability limit calculation system 300 of an embodiment of the present invention corresponds to a longitudinal multi-section power flow adjustment and thermal stability limit calculation method 100 of another embodiment of the present invention, and will not be repeated here.

[0161] Those skilled in the art will appreciate that the embodiments of the present application can be provided as methods, systems, or computer program products. Therefore, the application can adopt the form of a complete hardware embodiment, a complete software embodiment, or an embodiment in combination with software and hardware. Moreover, the application can adopt the form of a computer program product implemented on one or more computer-usable storage media (including but not limited to disk storage, CD-ROM, optical storage, etc.) that contain computer-usable program code. The scheme in the embodiment of the present application can be implemented in various computer languages, for example, object-oriented programming language Java and literal translation scripting language JavaScript, etc.

[0162] The present application is described with reference to the flowcharts and / or block diagrams of the methods, devices (systems), and computer program products according to the embodiments of the present application. It should be understood that each process and / or box in the flowchart and / or block diagram, as well as the combination of the processes and / or boxes in the flowchart and / or block diagram, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, a special-purpose computer, an embedded processor, or other programmable data processing device to produce a machine, so that the instructions executed by the processor of the computer or other programmable data processing device generate instructions for implementing the steps in the process. Figure 1 a process or multiple processes and / or boxes Figure 1 A device that provides the functions specified in a block or multiple blocks.

[0163] These computer program instructions may also be stored in a computer readable memory that can direct a computer or other programmable data processing device to work in a specific manner, so that the instructions stored in the computer readable memory produce an article of manufacture comprising an instruction device, which implements the process Figure 1 a process or multiple processes and / or boxes Figure 1The function specified in one or more boxes.

[0164] These computer program instructions can also be loaded onto a computer or other programmable data processing device so that a series of operational steps are executed on the computer or other programmable device to produce a computer-implemented process, thereby providing the instructions executed on the computer or other programmable device for implementing the process. Figure 1 a process or multiple processes and / or boxes Figure 1 A step that specifies a function in one or more boxes.

[0165] Although the preferred embodiments of the present application have been described, those skilled in the art may make additional changes and modifications to these embodiments once they have learned the basic creative concept. Therefore, the appended claims are intended to be interpreted as including the preferred embodiments and all changes and modifications that fall within the scope of the present application.

[0166] Obviously, those skilled in the art may make various changes and modifications to this application without departing from the spirit and scope of this application. Thus, if these modifications and variations of this application fall within the scope of the claims of this application and their equivalents, this application is intended to include these modifications and variations.

Claims

1. A method for longitudinal multi-section tidal current adjustment and thermal stability limit calculation, characterized in that: include: Read the state estimation data and offline operation mode data in the power grid intelligent dispatching system and integrate them to obtain online power flow data; Based on online power flow data, calculate the sensitivity of each generator and load to the section power. Before each round of power flow adjustment, determine the line with the lowest thermal stability margin and calculate the sensitivity. According to the sensitivity, the generators in the relevant area of ​​the longitudinal section are grouped to obtain the section margin release group, the section power balance group, the section blocked group and the regional power balance group; Considering optimizing the output of the blocked group in the section, taking the maximum total output capacity of the blocked group as the optimization goal and the maximum load rate section not exceeding the limit as the boundary condition, the generator output in the blocked group in the section is estimated to obtain the generator output of the blocked group; Based on the output of the blocked generators, a multi-section control power flow algorithm is used to automatically adjust and generate the target power flow of the power grid; Perform thermal stability check on each section after N-1 faults, and output the thermal stability limit of the longitudinal multi-section and the corresponding generator output.

2. The method according to claim 1, characterized in that Based on online power flow data, the sensitivity of each generator and load to the section power is calculated. The sensitivity is calculated based on the line with the lowest thermal stability margin determined before each round of power flow adjustment, including: Perform sensitivity analysis on the generators in the sending and receiving areas of the section to determine the generator adjustment order under the N-1 thermal stability constraint. Before each round of power flow adjustment, determine the line with the lowest thermal stability margin and calculate the sensitivity: Where K im is the sensitivity of generator m to section i, calculated according to formula (2). Where, i is the set of all lines in section i.

3. The method according to claim 1, characterized in that Considering the optimization of the output of the blocked section group, with the maximum total output capacity of the blocked group as the optimization goal and the boundary condition of the section with the highest load rate not exceeding the limit, the generator output of the blocked section group is estimated, and the generator output of the blocked group is obtained, including: Estimate the section power according to the sensitivity until a section among the multiple sections reaches the preset target power P T , or all units reach their upper limit, the maximum output of the blocked units can be calculated according to the following optimization model, with the boundary condition that the section power reaches the preset power P T 2. The unit output does not exceed the limit: Where K im is the sensitivity of generator m to section i, P sec0 is the initial power of the section, P m0 is the initial power of generator i, P max_m and P min_m are the upper and lower power limits of generator m respectively.

4. The method according to claim 1, wherein Based on the output of the blocked generators, a multi-section control power flow algorithm is used to automatically adjust and generate the target power flow of the power grid, including: Add the section active power deviation equation to the Newton method power flow equation: Where, ΔP seti is the active power deviation of section j, is the active power of section j, which is composed of N j The active power of the lines is added together to get P des_i is the active power target value of the section; The active power P of the mth machine in the kth control group g (m) is: P g (m)=f p (m)+α(k)ΔP vail (m) (5) Where, f p (m) is the topological constraint of the generator node, α(k) is the active power control factor of group k, ΔP vail (m) is the weighted active adjustable output of the generator; The active power expression of the distributed balancing machine is the same as that of formula (5). It and the section power control machine are collectively referred to as the control unit. A phase reference equation is added to each electrical island. If the m machines in the electrical island l are the phase reference, then: i m =θ 0l (6) Where θ m is the phase angle of the mth machine, θ 0l The phase angle reference set for electrical island l is taken as 0.

5. The method according to claim 1, wherein Perform thermal stability check on each section after N-1 faults, output the thermal stability limit of the longitudinal multi-section and the corresponding generator output, including: After the section flow adjustment is completed, perform thermal stability check on each section after N-1 faults: If a section exceeds the limit or is overloaded, the thermal stability auxiliary decision-making program will be called to ensure that all sections are within the limit, and the thermal stability limit of the longitudinal multi-section and the corresponding generator output will be output; If there is no section exceeding the limit or overloading, each control section in the channel will be increased at the same time according to the predetermined step size. The increased power of each control section can be distributed according to the proportion of the maximum current carrying capacity of the line. The section configuration and the adjustment group configuration remain unchanged. After the adjustment, the section thermal stability check is performed. If there is still no section exceeding the limit or overloading, continue to increase the section power according to the step size until the section exceeds the limit and is overloaded. Call the thermal stability auxiliary decision-making program to ensure that all sections are within the limit, and output the thermal stability limit of the longitudinal multi-section and the corresponding generator output.

6. A longitudinal multi-section tidal current adjustment and thermal stability limit calculation system, characterized in that: include: A data integration unit is used to read the state estimation data and offline operation mode data in the power grid intelligent dispatching system and integrate them to obtain online power flow data; The sensitivity calculation unit is used to calculate the sensitivity of each generator and load to the section power based on the online power flow data, and to calculate the sensitivity based on the line with the lowest thermal stability margin determined before each round of power flow adjustment; An adjustable equipment selection unit is used to group the generators in the relevant area of ​​the longitudinal section according to the sensitivity to obtain the section margin release group, the section power balance group, the section blocked group and the regional power balance group; The adjustable equipment power estimation unit is used to optimize the output of the blocked group in the section, taking the maximum total output capacity of the blocked group as the optimization goal and the maximum load rate section not exceeding the limit as the boundary condition, to estimate the output of the generators in the blocked group in the section, and obtain the output of the generators in the blocked group; The multi-section power flow adjustment unit is used to automatically adjust and generate the target power flow of the power grid based on the output of the blocked generator group using the multi-section power flow control algorithm; The thermal stability limit calculation unit is used to check the thermal stability of each section after N-1 faults, and output the thermal stability limits of the longitudinal multi-sections and the corresponding generator output.

7. The system according to claim 6, characterized in that Sensitivity calculation unit, including: The sensitivity calculation subunit is used to perform sensitivity analysis on the generators in the sending and receiving areas of the section, determine the generator adjustment order under the N-1 thermal stability constraint, determine the line with the lowest thermal stability margin before each round of power flow adjustment, and calculate the sensitivity: Where K im is the sensitivity of generator m to section i, calculated according to formula (2). Where, i is the set of all lines in section i.

8. The system according to claim 6, wherein: Adjustable device power estimation unit, including: The adjustable equipment power estimation subunit is used to estimate the section power according to the sensitivity until a section among multiple sections reaches the preset target power P T , or all units reach their upper limit, the maximum output of the blocked units can be calculated according to the following optimization model, with the boundary condition that the section power reaches the preset power P T 2. The unit output does not exceed the limit: Where K im is the sensitivity of generator m to section i, P sec0 is the initial power of the section, P m0 is the initial power of generator i, P max_m and P min_m are the upper and lower power limits of generator m respectively.

9. The system according to claim 6, wherein: Multi-section tidal flow adjustment unit, including: The multi-section power flow adjustment subunit is used to add the section active power deviation equation to the Newton method power flow equation: Where, ΔP seti is the active power deviation of section j, is the active power of section j, which is composed of N j The active power of the lines is added together to get P des_i is the active power target value of the section; The active power P of the mth machine in the kth control group g (m) is: P g (m)=f p (m)+α(k)ΔP vail (m) (5) Where, f p (m) is the topological constraint of the generator node, α(k) is the active power control factor of group k, ΔP vail (m) is the weighted active adjustable output of the generator; The active power expression of the distributed balancing machine is the same as that of formula (5). It and the section power control machine are collectively referred to as the control unit. A phase reference equation is added to each electrical island. If the m machines in the electrical island l are the phase reference, then: i m =θ 0l (6) Where θ m is the phase angle of the mth machine, θ 0l The phase angle reference set for electrical island l is taken as 0.

10. The system according to claim 6, wherein: Thermal stability limit calculation unit, including: The thermal stability check subunit is used to check the thermal stability of each section after N-1 faults after the section flow adjustment is completed: The first output generator output sub-unit is used to call the thermal stability auxiliary decision-making program if there is an over-limit or overload in the section to ensure that all sections are within the limit, and output the thermal stability limit of the longitudinal multi-section and the corresponding generator output; The second output generator output sub-unit is used to simultaneously increase the control sections in the channel according to the predetermined step size if there is no section exceeding the limit or overload. The increased power of each control section can be distributed according to the proportion of the maximum current carrying capacity of the line. The section configuration and the adjustment group configuration remain unchanged. After the adjustment, the section thermal stability check is performed. If there is still no exceeding the limit or overload, the section power is continued to be increased according to the step size until the section exceeds the limit and is overloaded. The thermal stability auxiliary decision-making program is called to ensure that all sections are within the limit, and the thermal stability limit of the longitudinal multi-section and the corresponding generator output are output.

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