Configuration method and device for embedded direct-current power transmission system of power grid

Abstract

The embodiment of the invention relates to the technical field of power system planning, in particular to a power grid embedded direct current power transmission system configuration method and device.According to the method, an embedded direct current configuration scheme is evaluated in stages, an optimal site selection scheme is identified, safety judgment serves as a first-stage core target, a safety bottom line is preferentially defined, and the optimal site selection scheme is obtained; on the one hand, the risk that an unsafe scheme enters a subsequent process is avoided from an evaluation logic source, the safety of project landing is improved, on the other hand, a traditional configuration method focuses on economical efficiency or static stability and neglects the key performance, namely dynamic stability, of the embedded direct current, and the engineering safety is improved. In the second stage, three middle-level indexes including the coverage economy, the static stability and the dynamic stability are defined, bottom-level indexes are refined, and full-dimension balance of investment cost, static safety and transient disturbance rejection is achieved.

Description

Technical Field

[0001] This application relates to the field of power system planning technology, and in particular to a method and apparatus for configuring a grid-embedded DC transmission system. Background Technology

[0002] With the large-scale grid connection of renewable energy and the increasing demand for power system interconnection, DC transmission technology has shown significant advantages in regulating the transmission capacity of transmission channels and has been widely used. As a flexible interconnection solution, embedded DC transmission systems can effectively improve the power mutual assistance capability between regional power grids and improve the stability and operating efficiency of AC power grids. However, when deploying embedded DC systems in regional power grids, the configuration scheme needs to comprehensively consider the operating characteristics of different power grid zones and whether the target grid structure after configuration meets the power system's safe and stable operation criteria, and whether it meets the objectives of economy, static stability, and dynamic stability. Traditional single-stage optimization methods are difficult to take into account the coordination between planning and operation, which may lead to insufficient efficiency or poor adaptability in actual operation.

[0003] Existing research in DC system planning often employs static capacity configuration or simple economic assessments, failing to adequately consider the dynamic operational constraints of regional power grids, which can easily lead to capacity redundancy or transmission bottlenecks. Furthermore, traditional methods typically separate planning from operational optimization, neglecting the coupling relationship between the two stages. The planning stage needs to reserve flexibility for the operational stage, while operational feedback necessitates adjustments to planning parameters. Therefore, there is an urgent need for a two-stage optimization configuration method based on the regional operation characteristics of the power grid, while also considering the safety of the target grid structure and the improvement of overall performance. This method should embed operational simulation into the planning stage to enhance the overall benefits and grid adaptability of the embedded DC system. Summary of the Invention

[0004] To address this, the present invention provides a configuration method and apparatus for a grid-embedded DC transmission system, which overcomes the problem that existing technologies often use static capacity configuration or simple economic evaluation in DC system planning, without fully considering the dynamic operation constraints of regional power grids, which can easily lead to capacity redundancy or transmission bottlenecks.

[0005] In a first aspect, embodiments of this application provide a configuration method for a power grid embedded DC transmission system. This includes:

[0006] Step S1: Construct a two-stage embedded DC evaluation system based on the power system safety and stability operation criteria. The evaluation system includes: the first stage is to determine whether all configurable point schemes in the target grid meet the safety requirements based on the power system safety and stability operation criteria; the second stage is to analyze the mid-level indicators of economy, static stability, and dynamic stability, as well as the bottom-level evaluation indicators corresponding to each mid-level indicator, for the schemes that meet the safety requirements of the first stage, and construct a set of embedded DC configuration schemes based on the regional operation characteristics.

[0007] Step S2: Calculate the power system safety and stability operation index values ​​of each embedded DC configuration scheme in the first stage, and preliminarily screen out the embedded DC channel candidate schemes that meet the power system safety requirements based on the safety and stability operation index values.

[0008] Step S3: Calculate the underlying index values ​​of the economy, static stability, and dynamic stability of the embedded DC channel alternative schemes that meet the first stage security requirements in the second stage. Calculate the comprehensive superiority score of each embedded DC channel alternative scheme based on the analytic hierarchy process (AHP). Arrange the scores in descending order to determine the optimal addressing scheme.

[0009] Furthermore, in step S1, the parameters used to determine whether all configurable point schemes in the target grid meet the safety requirements include: the static stability reserve coefficient Kp calculated according to the power angle criterion, the static stability reserve coefficient Kv calculated according to the reactive voltage criterion, the frequency deviation during normal operation of the power system, the sum of the absolute values ​​of positive and negative voltage deviations, and the N-1 verification index.

[0010] The underlying indicators of the economic indicators include: investment cost and network loss indicators;

[0011] The underlying indicators of the static stability index include: power flow balance, cross-sectional transmission capacity improvement ratio, static voltage stability L index, embedded DC multi-infeed short-circuit ratio deviation index, and embedded DC sending-end and receiving-end short-circuit ratio.

[0012] The underlying indicators of the dynamic stability index include: power angle severity index, transient voltage recovery speed, maximum rate of change of transient frequency, and commutation failure immunity factor.

[0013] Furthermore, in step S1, constructing a set of embedded DC configuration schemes based on partitioned operation characteristics includes:

[0014] Based on the characteristics and voltage levels of different zones within the target grid, nodes are selected within each zone as candidate embedding points for the sending or receiving ends of the embedded DC channel. Different candidate embedding points are then combined to form an embedded DC configuration scheme, creating a scheme matrix.

[0015]

[0016] In the formula, The matrix consisting of all alternative solutions; For the first One sender alternative embedding point and the first The alternative scheme is composed of a number of alternative embedding points at the receiving end; This represents the total number of alternative embedding points for the sending end. This represents the total number of candidate embedding points at the receiving end.

[0017] matrix Arrange them in rows sequentially into 1 row. Column matrix :

[0018]

[0019] In the formula, A matrix consisting of all the alternative configurations of embedded DC channels in the target network structure; Indicates the first One embedded DC channel alternative configuration option; An overview of alternative configuration options for embedded DC-DC channels, and .

[0020] Further, in step S2, the formulas for calculating the static stability reserve coefficients Kp and Kv are as follows:

[0021] The expression for the static stability reserve coefficient calculated according to the work angle criterion is as follows:

[0022]

[0023] In the formula, For the first Static stability reserve coefficient calculated based on the power angle criterion under one alternative scheme; For the first The static stability limit power under each alternative scheme, that is, the maximum transmission power of the entire system; This refers to the transmission power during normal system operation. This represents the total number of alternative options.

[0024] The expression for the static stability reserve coefficient calculated according to the reactive voltage criterion is as follows:

[0025]

[0026] In the formula, For the first The first alternative plan The static stability reserve coefficient of each busbar is calculated based on the reactive voltage criterion. For the first The target network structure under the alternative scheme is the first one Normal voltage of the busbar; For the first The target network structure under the alternative scheme is the first one Critical voltage value of a single busbar; For the first The static stability reserve coefficient calculated based on the reactive power voltage criterion under the 1st alternative scheme represents the 1st... The minimum static stability reserve coefficient of all buses in the target grid under the alternative scheme, calculated according to the reactive voltage criterion; This represents the total number of alternative options. The total number of voltage buses in the target grid structure;

[0027] In step S2, the embedded DC channel alternative scheme is determined to meet the power system security requirements based on the following constraints and N-1 verification indicators:

[0028]

[0029] In the formula, For the first Static stability reserve coefficient calculated based on the work angle criterion under one alternative scheme. Greater than or equal to 15% and less than or equal to 20%; For the first Static stability reserve coefficient calculated based on reactive power and voltage criteria under one alternative scheme. Greater than or equal to 10% and less than or equal to 15%; For the first Frequency deviation values ​​under each alternative scheme; For the first The first alternative plan The positive and negative deviation values ​​of the voltage of each busbar; For the first The first alternative plan Rated voltage of the busbar; This represents the total number of alternative options. This represents the total number of voltage buses in the target grid structure.

[0030] Furthermore, in step S2, after initially screening out the embedded DC channel alternatives that meet the power system security requirements, a new matrix is ​​constructed:

[0031]

[0032] In the formula, A matrix consisting of all embedded DC channel alternative configuration schemes that meet the constraints of the first stage of power system safe and stable operation; This represents the l-th embedded DC channel alternative configuration that satisfies the first-stage constraints; This represents the total number of alternative solutions that satisfy the first-stage constraints.

[0033] Further, in step S3, calculating the underlying indicators of the economic indicators includes:

[0034] The expression for investment cost is:

[0035]

[0036] In the formula, Let l be the investment cost of the l-th alternative that has met the first-stage constraints; The one-time investment cost of new equipment for the l-th alternative scheme that has met the first-stage constraints; The annual operating and maintenance cost of the new equipment for the l-th alternative scheme that has met the first stage constraints; The land cost of the l-th alternative that has met the first-stage constraints; This represents the total number of all alternative solutions that satisfy the first-stage constraints.

[0037] The expression for the network loss indicator is:

[0038]

[0039] In the formula, The network loss index is the l-th alternative scheme that has met the first-stage constraints; Let be the active power of the l-th alternative that has met the first-stage constraints; Let be the active power of the l-th alternative that has met the first-stage constraints; Let be the active power of the l-th alternative scheme that has met the first-stage constraints; Let l be the capacity base value of the l-th alternative that has met the first-stage constraints; This represents the total number of alternative solutions that satisfy the first-stage constraints.

[0040] Further, in step S3, calculating the underlying index of the static stability index includes:

[0041] The expression for the power flow balance is:

[0042]

[0043] In the formula, Let l represent the weighted power flow entropy of the l-th alternative that has met the first-stage constraints; Let be the constant coefficient of the l-th alternative that has satisfied the first-stage constraints; The transmission line load factor in the target transmission section of the l-th alternative scheme that has met the first-stage constraints. The corresponding weighting coefficients; For the l-th alternative scheme that has met the first-stage constraints, the transmission line load factor in the target transmission section is... The corresponding probability coefficient; The total number of transmission lines in the target transmission section; This represents the total number of all alternative solutions that satisfy the first-stage constraints.

[0044] The expression for the cross-sectional transmission capacity enhancement ratio is:

[0045]

[0046] In the formula, The cross-sectional transmission capacity enhancement ratio of the l-th alternative scheme that has met the first stage constraints; , The transmission capacity of the transmission section before and after construction for the first and second embedded DC alternative schemes that have met the first stage constraints, respectively; This represents the total number of all alternative solutions that satisfy the first-stage constraints.

[0047] The expression for the static voltage stability index L is:

[0048]

[0049] In the formula, This represents the l-th alternative solution that has satisfied the first-stage constraints. matrix; Let be the load node self-admittance matrix of the l-th alternative scheme that has met the first-stage constraints; Let be the load node mutual admittance matrix of the l-th alternative scheme that has met the first stage constraints; For the l-th alternative solution that has already met the first-stage constraints, the... Local static voltage stability index of each load node; Let be the complex voltage of the c-th generator node under the l-th alternative scheme that has met the first-stage constraints; For the l-th alternative solution that has already met the first-stage constraints, the... Complex voltage of each load node; Let be the load participation factor for the l-th alternative that has met the first-stage constraints. The first of the matrix Line number Column elements; The static voltage stability index is given by the l-th alternative scheme that has met the first-stage constraints. This represents the total number of load nodes. This represents the total number of all alternative solutions that satisfy the first-stage constraints. This represents the total number of generator nodes.

[0050] The expression for the embedded DC multi-infeed short-circuit ratio deviation index is as follows:

[0051]

[0052] In the formula, The embedded DC multi-infeed short-circuit ratio deviation index represents the l-th alternative scheme that has met the first-stage constraints. This represents the average multi-infeed short-circuit ratio within the target area before configuring the target embedded DC transmission channel; This indicates that after the configuration of the l-th embedded DC transmission channel that has met the first-stage constraints is completed, the number of inputs fed into the multi-infeed AC / DC system is... Multiple feed-in short-circuit ratio at each DC landing port; Indicates the first input in a multi-input AC / DC system Multiple feed-in short-circuit ratio at each DC landing port; Indicates converter station Short-circuit capacity at the location; and These are the rated transmission capacities of the DC system; For converter bus voltage change Time-commutating bus The change in voltage; This represents the total number of all alternative solutions that satisfy the first-stage constraints. This represents the total number of DC landing ports fed into a multi-infeed AC / DC system. The total number of DC lines fed into a multi-infeed AC / DC system;

[0053] The underlying metrics for calculating the dynamic stability index include:

[0054] The expression for the power angle severity index is:

[0055]

[0056] In the formula, The power angle severity index is the l-th alternative scheme that has met the first stage constraints. , These are the times when a three-phase short-circuit fault occurs on the busbar of the transmission section under the l-th alternative scheme that has met the first stage constraints, respectively, and the times when the maximum and minimum power angles in the system are respectively. This represents the total number of all alternative solutions that satisfy the first-stage constraints.

[0057] The expression for the transient voltage recovery rate is:

[0058]

[0059] In the formula, The transient voltage recovery rate of the l-th alternative scheme that has met the first stage constraints; The moment when a three-phase short-circuit fault occurs on the busbar of the transmission section under the l-th alternative scheme that has met the first stage constraints; The moment when the voltage recovers to 90% of the pre-fault steady-state value after a three-phase short-circuit fault occurs on the busbar of the transmission section under the l-th alternative scheme that has met the first stage constraints; This represents the total number of all alternative solutions that satisfy the first-stage constraints.

[0060] The expression for the maximum rate of change of the transient frequency is:

[0061]

[0062] In the formula, Let l be the maximum rate of change of transient frequency of the l-th alternative that has met the first-stage constraints; , These are the start time of a three-phase short-circuit fault occurring on the busbar of the transmission section under the l-th alternative scheme that has met the first-stage constraints, and the time when the frequency drops to the minimum value after the fault occurs. , For the l-th alternative solution that has already met the first-stage constraints, under the condition that... and Any two moments between; , These are the frequency values ​​when a three-phase short-circuit fault occurs on the busbar of the transmission section under the l-th alternative scheme that has met the first-stage constraints, and the minimum frequency value after the fault occurs, respectively. , For the l-th alternative solution that has satisfied the first-stage constraints, respectively under the following conditions , Frequency value at any given time; This represents the total number of all alternative solutions that satisfy the first-stage constraints.

[0063] The expression for the phase-switching failure immune factor is:

[0064]

[0065] In the formula, The DC commutation failure immune factor index for the l-th alternative scheme that has met the first stage constraints; The rated voltage value of the AC bus of the l-th alternative scheme that has met the first stage constraint conditions; The rated active power of the l-th alternative that has met the first stage constraints; Let be the impedance that causes commutation failure for the l-th alternative scheme that has met the first-stage constraints; This represents the total number of alternative solutions that satisfy the first-stage constraints.

[0066] Furthermore, in step S3, the specific steps for calculating the overall superiority score based on the analytic hierarchy process include:

[0067] Step S31: For the mid-level indicators of economy, static stability, and dynamic stability, and their corresponding bottom-level indicators, construct judgment moments using an importance scale of 1-9;

[0068] Step S32: Calculate the maximum eigenvalue λmax of the judgment matrix, and verify consistency using the consistency ratio. When the consistency ratio... When <0.1, the decision matrix satisfies the consistency requirement;

[0069] Step S33: When the judgment matrix satisfies the consistency requirement, normalize the eigenvector corresponding to the largest eigenvalue of the judgment matrix to obtain the weight vector.

[0070] The expression for the judgment matrix B is:

[0071]

[0072] In the formula, This serves as a scale for the relative importance of three intermediate-level indicators—economic efficiency, static stability, and dynamic stability—or, respectively, the underlying indicators corresponding to these three intermediate-level indicators. , hour, ; , , , ; for and The relative importance scaling function between them; To determine the order of a matrix;

[0073] The consistency ratio The expression is as follows:

[0074]

[0075] In the formula, To determine the largest eigenvalue of a matrix ; To determine the order of a matrix; The average random consistency index is obtained by constructing multiple sample matrices using random methods and then performing a series of calculations. It is only related to the order of the judgment matrix. Related, When the value is 1-9, the corresponding They are respectively , , , , , , , , When the consistency ratio If the value is less than 0.1, perform the following steps; otherwise, adjust the judgment matrix to satisfy the consistency check.

[0076] The expression for the weight vector Z is:

[0077]

[0078] In the formula, These are the weights of the three mid-level indicators—economic efficiency, static stability, and dynamic stability—or the corresponding bottom-level indicators in the 1st, 2nd, ..., dth, ..., Qth embedded DC channel alternative configuration schemes that have met the first-stage constraints.

[0079] Further, in step S3, the expression for calculating the comprehensive superiority score is:

[0080]

[0081] In the formula, Indicates rating, This represents the indicator value after positive transformation and standardization within the same level;

[0082] The optimal addressing scheme identification includes:

[0083] Construct a comprehensive superiority scoring matrix O.

[0084]

[0085] In the formula, They are respectively the 1st, 2nd, ..., 1st ,...,No. The overall superiority score of the embedded DC channel alternative configuration scheme that has met the first stage constraints;

[0086] The elements in the result matrix are sorted in descending order, and the maximum value is selected. The configuration scheme corresponding to the maximum value is the embedded DC configuration scheme that meets the requirements for safe and stable operation of the first stage power system and has the highest overall superiority.

[0087] Secondly, embodiments of this application provide a power grid embedded DC transmission system configuration device, comprising:

[0088] The evaluation system construction module is used to construct an embedded DC evaluation system based on the criteria for safe and stable operation of the power system. The evaluation system includes a first stage and a second stage.

[0089] The operation index calculation module, which is connected to the evaluation system construction module, is used to calculate the power system safety and stability operation index values ​​of each embedded DC configuration scheme in the first stage, and to preliminarily screen out the embedded DC channel candidate schemes that meet the power system safety requirements based on the safety and stability operation index values.

[0090] The underlying index calculation module is connected to the evaluation system construction module and the operation index calculation module, respectively. It is used to calculate the underlying index values ​​of the economy, static stability and dynamic stability of the embedded DC channel alternative scheme that meets the first stage security requirements in the second stage. Based on the analytic hierarchy process, it calculates the comprehensive superiority score of each embedded DC channel alternative scheme, and determines the optimal addressing scheme after arranging the scores in descending order.

[0091] Compared with existing technologies, the beneficial effects of this invention are as follows: Traditional methods often evaluate safety, economy, and stability in the same stage, potentially resulting in solutions with high overall scores but failing to meet safety standards. This leads to wasted computational resources in the early stages and rework in later stages. This invention evaluates in stages, prioritizing safety assessment as the core objective of the first stage. It clearly defines the safety baseline, avoiding the risk of unsafe solutions entering subsequent processes from the source of the evaluation logic, thus improving the safety of project implementation. Furthermore, traditional configuration methods often focus on economy or static stability, neglecting dynamic stability, a key performance characteristic of embedded DC systems. In this invention, the second stage clearly covers three mid-level indicators: economy, static stability, and dynamic stability, and refines the underlying indicators, achieving a comprehensive balance between investment cost, static safety, and transient immunity.

[0092] Furthermore, this invention takes into account that the number of configurable point schemes for the target network structure is usually large. If all schemes are directly calculated in all dimensions of security and comprehensive performance, a large amount of invalid calculations will be generated. However, this invention can eliminate some insecure schemes through the first stage of screening, so that the comprehensive evaluation in the subsequent second stage focuses only on the schemes that meet the security standards, which greatly reduces the amount of calculation and improves the overall configuration decision efficiency.

[0093] Furthermore, considering that traditional comprehensive evaluation often uses equal weights or empirical weights, neglecting the differences in the importance of indicators under different engineering scenarios, this invention transforms the importance of indicators into a quantifiable and verifiable weight vector by constructing a judgment matrix, consistency verification, and normalized weights. This avoids decision-making bias caused by subjective assignment, making the comprehensive score more in line with actual engineering needs. By focusing on the core in stages and covering performance in all dimensions, this invention not only solves many pain points of traditional configuration methods, but also provides a safe, reliable, and practical configuration solution for the planning and design of embedded DC transmission systems, directly improving the scientific nature and engineering application value of power grid planning. Attached Figure Description

[0094] Figure 1 This embodiment provides a flowchart for calculating the overall superiority score based on the analytic hierarchy process.

[0095] Figure 2 A flowchart for configuring a power grid embedded DC transmission system. Detailed Implementation

[0096] To make the objectives and advantages of the present invention clearer, the present invention will be further described below with reference to embodiments; it should be understood that the specific embodiments described herein are merely for explaining the present invention and are not intended to limit the present invention.

[0097] Preferred embodiments of the present invention will now be described with reference to the accompanying drawings. Those skilled in the art should understand that these embodiments are merely illustrative of the technical principles of the present invention and are not intended to limit the scope of protection of the present invention.

[0098] Please see Figure 1-2 As shown, Figure 1 This is a flowchart of the calculation of the overall superiority score based on the analytic hierarchy process provided in the embodiment. Figure 2 A flowchart for configuring a power grid embedded DC transmission system.

[0099] The technical solution provided in this application includes the following steps:

[0100] Step S1: Construct a two-stage embedded DC evaluation system based on the power system safety and stability operation criteria. The evaluation system includes: the first stage is to determine whether all configurable point schemes in the target grid meet the safety requirements based on the power system safety and stability operation criteria; the second stage is to analyze the mid-level indicators of economy, static stability, and dynamic stability, as well as the bottom-level evaluation indicators corresponding to each mid-level indicator, for the schemes that meet the safety requirements of the first stage, and construct a set of embedded DC configuration schemes based on the regional operation characteristics.

[0101] Step S2: Calculate the power system safety and stability operation index values ​​of each embedded DC configuration scheme in the first stage, and preliminarily screen out the embedded DC channel candidate schemes that meet the power system safety requirements based on the safety and stability operation index values.

[0102] Step S3: Calculate the underlying index values ​​of the economy, static stability, and dynamic stability of the embedded DC channel alternative schemes that meet the first stage security requirements in the second stage. Calculate the comprehensive superiority score of each embedded DC channel alternative scheme based on the analytic hierarchy process (AHP). Arrange the scores in descending order to determine the optimal addressing scheme.

[0103] This invention addresses the common practice in traditional methods of evaluating safety, economy, and stability in the same stage. This can result in solutions with high overall scores but failing to meet safety standards, leading to wasted computational resources in the early stages and rework in later stages. This invention adopts a phased evaluation approach, prioritizing safety assessment as the core objective of the first stage. It prioritizes defining the safety baseline and avoids the risk of unsafe solutions entering subsequent processes from the source of the evaluation logic, thereby improving the safety of project implementation. On the other hand, traditional configuration methods often focus on economy or static stability, neglecting dynamic stability, a key performance characteristic of embedded DC. In this invention, the second stage clearly covers three mid-level indicators: economy, static stability, and dynamic stability, and refines the bottom-level indicators to achieve a comprehensive balance of investment cost, static safety, and transient immunity.

[0104] Specifically, in step S1, the parameters used to determine whether all configurable point schemes in the target grid meet the safety requirements include: the static stability reserve coefficient Kp calculated according to the power angle criterion, the static stability reserve coefficient Kv calculated according to the reactive voltage criterion, the frequency deviation during normal operation of the power system, the sum of the absolute values ​​of positive and negative voltage deviations, and the N-1 verification index.

[0105] The underlying indicators of the economic indicators include: investment cost and network loss indicators;

[0106] The underlying indicators of the static stability index include: power flow balance, cross-sectional transmission capacity improvement ratio, static voltage stability L index, embedded DC multi-infeed short-circuit ratio deviation index, and embedded DC sending-end and receiving-end short-circuit ratio.

[0107] The underlying indicators of the dynamic stability index include: power angle severity index, transient voltage recovery speed, maximum rate of change of transient frequency, and commutation failure immunity factor.

[0108] Specifically, in step S1, constructing a set of embedded DC configuration schemes based on partitioned operation characteristics includes:

[0109] Based on the characteristics and voltage levels of different zones within the target grid, nodes are selected within each zone as candidate embedding points for the sending or receiving ends of the embedded DC channel. Different candidate embedding points are then combined to form an embedded DC configuration scheme, creating a scheme matrix.

[0110]

[0111] In the formula, The matrix consisting of all alternative solutions; For the first One sender alternative embedding point and the first The alternative scheme is composed of a number of alternative embedding points at the receiving end; This represents the total number of alternative embedding points for the sending end. This represents the total number of candidate embedding points at the receiving end.

[0112] matrix Arrange them in rows sequentially into 1 row. Column matrix :

[0113]

[0114] In the formula, A matrix consisting of all the alternative configurations of embedded DC channels in the target network structure; Indicates the first One embedded DC channel alternative configuration option; An overview of alternative configuration options for embedded DC-DC channels, and .

[0115] Specifically, in step S2, the formulas for calculating the static stability reserve coefficients Kp and Kv are as follows:

[0116] The expression for the static stability reserve coefficient calculated according to the work angle criterion is as follows:

[0117]

[0118] In the formula, For the first Static stability reserve coefficient calculated based on the power angle criterion under one alternative scheme; For the first The static stability limit power under each alternative scheme, that is, the maximum transmission power of the entire system; This refers to the transmission power during normal system operation. This represents the total number of alternative options.

[0119] The expression for the static stability reserve coefficient calculated according to the reactive voltage criterion is as follows:

[0120]

[0121] In the formula, For the first The first alternative plan The static stability reserve coefficient of each busbar is calculated based on the reactive voltage criterion. For the first The target network structure under the alternative scheme is the first one Normal voltage of the busbar; For the first The target network structure under the alternative scheme is the first one Critical voltage value of a single busbar; For the first The static stability reserve coefficient calculated based on the reactive power voltage criterion under the 1st alternative scheme represents the 1st... The minimum static stability reserve coefficient of all buses in the target grid under the alternative scheme, calculated according to the reactive voltage criterion; This represents the total number of alternative options. The total number of voltage buses in the target grid structure;

[0122] In step S2, the embedded DC channel alternative scheme is determined to meet the power system security requirements based on the following constraints and N-1 verification indicators:

[0123]

[0124] In the formula, For the first The static stability reserve coefficient calculated according to the work angle criterion under the alternative schemes, in accordance with the requirements of GB38755-2019, It should be greater than or equal to 15% and less than or equal to 20%; For the first The static stability reserve factor calculated based on the reactive power voltage criterion under the alternative schemes, according to the requirements of GB 38755-2019, It should be greater than or equal to 10% and less than or equal to 15%; For the first Frequency deviation values ​​under each alternative scheme; For the first The first alternative plan The positive and negative deviation values ​​of the voltage of each busbar; For the first The first alternative plan Rated voltage of the busbar; This represents the total number of alternative options. This represents the total number of voltage buses in the target grid structure.

[0125] In this invention, considering that the number of configurable point schemes for the target network structure is usually large, if all schemes are directly calculated in all dimensions of security and comprehensive performance, a large amount of invalid calculation will be generated. However, this invention can eliminate some insecure schemes through the first stage of screening, so that the subsequent second stage of comprehensive evaluation focuses only on the schemes that meet the security standards, which greatly reduces the amount of calculation and improves the efficiency of overall configuration decision-making.

[0126] Specifically, in step S2, after initially screening out the embedded DC channel alternatives that meet the power system security requirements, a new matrix is ​​constructed:

[0127]

[0128] In the formula, A matrix consisting of all embedded DC channel alternative configuration schemes that meet the constraints of the first stage of power system safe and stable operation; This represents the l-th embedded DC channel alternative configuration that satisfies the first-stage constraints; This represents the total number of alternative solutions that satisfy the first-stage constraints.

[0129] Specifically, in step S3, calculating the underlying indicators of the economic indicators includes:

[0130] The expression for investment cost is:

[0131]

[0132] In the formula, Let l be the investment cost of the l-th alternative that has met the first-stage constraints; The one-time investment cost of new equipment for the l-th alternative scheme that has met the first-stage constraints; The annual operating and maintenance cost of the new equipment for the l-th alternative scheme that has met the first stage constraints; The land cost of the l-th alternative that has met the first-stage constraints; This represents the total number of all alternative solutions that satisfy the first-stage constraints.

[0133] The expression for the network loss indicator is:

[0134]

[0135] In the formula, The network loss index is the l-th alternative scheme that has met the first-stage constraints; Let be the active power of the l-th alternative that has met the first-stage constraints; Let be the active power of the l-th alternative that has met the first-stage constraints; Let be the active power of the l-th alternative scheme that has met the first-stage constraints; Let l be the capacity base value of the l-th alternative that has met the first-stage constraints; This represents the total number of alternative solutions that satisfy the first-stage constraints.

[0136] Specifically, in step S3, calculating the underlying index of the static stability index includes:

[0137] The expression for the power flow balance is:

[0138]

[0139] In the formula, Let l represent the weighted power flow entropy of the l-th alternative that has met the first-stage constraints; Let be the constant coefficient of the l-th alternative that has satisfied the first-stage constraints; The transmission line load factor in the target transmission section of the l-th alternative scheme that has met the first-stage constraints. The corresponding weighting coefficients; For the l-th alternative scheme that has met the first-stage constraints, the transmission line load factor in the target transmission section is... The corresponding probability coefficient; The total number of transmission lines in the target transmission section; This represents the total number of all alternative solutions that satisfy the first-stage constraints.

[0140] The expression for the cross-sectional transmission capacity enhancement ratio is:

[0141]

[0142] In the formula, The cross-sectional transmission capacity enhancement ratio of the l-th alternative scheme that has met the first stage constraints; , The transmission capacity of the transmission section before and after construction for the first and second embedded DC alternative schemes that have met the first stage constraints, respectively; This represents the total number of all alternative solutions that satisfy the first-stage constraints.

[0143] The expression for the static voltage stability index L is:

[0144]

[0145] In the formula, This represents the l-th alternative solution that has satisfied the first-stage constraints. matrix; Let be the load node self-admittance matrix of the l-th alternative scheme that has met the first-stage constraints; Let be the load node mutual admittance matrix of the l-th alternative scheme that has met the first stage constraints; For the l-th alternative solution that has already met the first-stage constraints, the... Local static voltage stability index of each load node; Let be the complex voltage of the c-th generator node under the l-th alternative scheme that has met the first-stage constraints; For the l-th alternative solution that has already met the first-stage constraints, the... Complex voltage of each load node; Let be the load participation factor for the l-th alternative that has met the first-stage constraints. The first of the matrix Line number Column elements; The static voltage stability index is given by the l-th alternative scheme that has met the first-stage constraints. This represents the total number of load nodes. This represents the total number of all alternative solutions that satisfy the first-stage constraints. This represents the total number of generator nodes.

[0146] The expression for the embedded DC multi-infeed short-circuit ratio deviation index is as follows:

[0147]

[0148] In the formula, The embedded DC multi-infeed short-circuit ratio deviation index represents the l-th alternative scheme that has met the first-stage constraints. This represents the average multi-infeed short-circuit ratio within the target area before configuring the target embedded DC transmission channel; This indicates that after the configuration of the l-th embedded DC transmission channel that has met the first-stage constraints is completed, the number of inputs fed into the multi-infeed AC / DC system is... Multiple feed-in short-circuit ratio at each DC landing port; Indicates the first input in a multi-input AC / DC system Multiple feed-in short-circuit ratio at each DC landing port; Indicates converter station Short-circuit capacity at the location; and These are the rated transmission capacities of the DC system; For converter bus voltage change Time-commutating bus The change in voltage; This represents the total number of all alternative solutions that satisfy the first-stage constraints. This represents the total number of DC landing ports fed into a multi-infeed AC / DC system. The total number of DC lines fed into a multi-infeed AC / DC system;

[0149] The underlying metrics for calculating the dynamic stability index include:

[0150] The expression for the power angle severity index is:

[0151]

[0152] In the formula, The power angle severity index is the l-th alternative scheme that has met the first stage constraints. , These are the times when a three-phase short-circuit fault occurs on the busbar of the transmission section under the l-th alternative scheme that has met the first stage constraints, respectively, and the times when the maximum and minimum power angles in the system are respectively. This represents the total number of all alternative solutions that satisfy the first-stage constraints.

[0153] The expression for the transient voltage recovery rate is:

[0154]

[0155] In the formula, The transient voltage recovery rate of the l-th alternative scheme that has met the first stage constraints; The moment when a three-phase short-circuit fault occurs on the busbar of the transmission section under the l-th alternative scheme that has met the first stage constraints; The moment when the voltage recovers to 90% of the pre-fault steady-state value after a three-phase short-circuit fault occurs on the busbar of the transmission section under the l-th alternative scheme that has met the first stage constraints; This represents the total number of all alternative solutions that satisfy the first-stage constraints.

[0156] The expression for the maximum rate of change of the transient frequency is:

[0157]

[0158] In the formula, Let l be the maximum rate of change of transient frequency of the l-th alternative that has met the first-stage constraints; , These are the start time of a three-phase short-circuit fault occurring on the busbar of the transmission section under the l-th alternative scheme that has met the first-stage constraints, and the time when the frequency drops to the minimum value after the fault occurs. , For the l-th alternative solution that has already met the first-stage constraints, under the condition that... and Any two moments between; , These are the frequency values ​​when a three-phase short-circuit fault occurs on the busbar of the transmission section under the l-th alternative scheme that has met the first-stage constraints, and the minimum frequency value after the fault occurs, respectively. , For the l-th alternative solution that has satisfied the first-stage constraints, respectively under the following conditions , Frequency value at any given time; This represents the total number of all alternative solutions that satisfy the first-stage constraints.

[0159] The expression for the phase-switching failure immune factor is:

[0160]

[0161] In the formula, The DC commutation failure immune factor index for the l-th alternative scheme that has met the first stage constraints; The rated voltage value of the AC bus of the l-th alternative scheme that has met the first stage constraint conditions; The rated active power of the l-th alternative that has met the first stage constraints; Let be the impedance that causes commutation failure for the l-th alternative scheme that has met the first-stage constraints; This represents the total number of alternative solutions that satisfy the first-stage constraints.

[0162] Specifically, in step S3, the specific steps for calculating the overall superiority score based on the analytic hierarchy process include:

[0163] Step S31: For the mid-level indicators of economy, static stability, and dynamic stability, and their corresponding bottom-level indicators, construct judgment moments using an importance scale of 1-9;

[0164] Step S32: Calculate the maximum eigenvalue λmax of the judgment matrix, and verify consistency using the consistency ratio. When the consistency ratio... When <0.1, the decision matrix satisfies the consistency requirement;

[0165] Step S33: When the judgment matrix satisfies the consistency requirement, normalize the eigenvector corresponding to the largest eigenvalue of the judgment matrix to obtain the weight vector.

[0166] The expression for the judgment matrix B is:

[0167]

[0168] In the formula, This serves as a scale for the relative importance of three intermediate-level indicators—economic efficiency, static stability, and dynamic stability—or, respectively, the underlying indicators corresponding to these three intermediate-level indicators. , hour, ; , , , ; for and The relative importance scaling function between them; To determine the order of a matrix;

[0169] In this embodiment, when the indicator and When indicators are considered equally important, their relative importance scale =1; when the indicator is 1 and When an indicator is considered more important than another, its relative importance scale The value is 3; when the indicator is 3. and When an indicator is considered more important than another, its relative importance scale The value is 5; when the indicator is 5. and When an indicator is considered very important, its relative importance scale The value is 7; when the indicator is 7. and When an indicator is strongly important, its relative importance scale The value is 9; when the indicator is 9. and When the importance of an indicator falls between the two adjacent importance scales mentioned above, its relative importance scale is... Take 2, 4, 6, and 8 respectively.

[0170] The consistency ratio The expression is as follows:

[0171]

[0172] In the formula, To determine the largest eigenvalue of a matrix ; To determine the order of a matrix; The average random consistency index is obtained by constructing multiple sample matrices using random methods and then performing a series of calculations. It is only related to the order of the judgment matrix. Related, When the value is 1-9, the corresponding They are respectively , , , , , , , , When the consistency ratio If the value is less than 0.1, perform the following steps; otherwise, adjust the judgment matrix to satisfy the consistency check.

[0173] The expression for the weight vector Z is:

[0174]

[0175] In the formula, These are the weights of the three mid-level indicators—economic efficiency, static stability, and dynamic stability—or the corresponding bottom-level indicators in the 1st, 2nd, ..., dth, ..., Qth embedded DC channel alternative configuration schemes that have met the first-stage constraints.

[0176] Specifically, in step S3, the expression for calculating the comprehensive superiority score is:

[0177]

[0178] In the formula, Indicates rating, This represents the indicator value after positiveization and standardization within the same level. When representing the lower-level indicators corresponding to the three intermediate-level indicators of economic efficiency, static stability, and dynamic stability after positive transformation and standardization, S represents the corresponding intermediate-level indicator value, denoted as . ;when When representing the three mid-level evaluation indicators after positiveization and standardization, S represents the high-level indicator value, that is, the comprehensive superiority score of the embedded DC channel alternative configuration scheme that has met the first-stage constraints, denoted as .

[0179] Specifically, in step S3, the identification of the optimal addressing scheme includes:

[0180] Construct a comprehensive superiority scoring matrix O.

[0181]

[0182] In the formula, They are respectively the 1st, 2nd, ..., 1st ,...,No. The overall superiority score of the embedded DC channel alternative configuration scheme that has met the first stage constraints;

[0183] The elements in the result matrix are sorted in descending order, and the maximum value is selected. The configuration scheme corresponding to the maximum value is the embedded DC configuration scheme that meets the requirements for safe and stable operation of the first stage power system and has the highest overall superiority.

[0184] This invention addresses the common practice in traditional comprehensive evaluations of using equal or empirical weights, which neglects the differences in the importance of indicators across various engineering scenarios. By constructing a judgment matrix, performing consistency checks, and normalizing weights, this invention transforms the importance of indicators into a quantifiable and verifiable weight vector. This avoids decision-making biases caused by subjective assignment, making the comprehensive score more aligned with actual engineering needs. By focusing on core aspects in stages and covering performance across all dimensions, this invention not only solves many pain points of traditional configuration methods but also provides a safe, reliable, and practical configuration solution for the planning and design of embedded DC transmission systems, directly enhancing the scientific nature and engineering application value of power grid planning.

[0185] The power grid embedded DC transmission system configuration device provided in this application embodiment includes:

[0186] The evaluation system construction module is used to construct an embedded DC evaluation system based on the criteria for safe and stable operation of the power system. The evaluation system includes a first stage and a second stage.

[0187] The operation index calculation module, which is connected to the evaluation system construction module, is used to calculate the power system safety and stability operation index values ​​of each embedded DC configuration scheme in the first stage, and to preliminarily screen out the embedded DC channel candidate schemes that meet the power system safety requirements based on the safety and stability operation index values.

[0188] The underlying index calculation module is connected to the evaluation system construction module and the operation index calculation module, respectively. It is used to calculate the underlying index values ​​of the economy, static stability and dynamic stability of the embedded DC channel alternative scheme that meets the first stage security requirements in the second stage. Based on the analytic hierarchy process, it calculates the comprehensive superiority score of each embedded DC channel alternative scheme, and determines the optimal addressing scheme after arranging the scores in descending order.

[0189] The above embodiments are merely illustrative examples and are not intended to limit the implementation. Those skilled in the art will recognize that other variations or modifications can be made based on the above description. It is neither necessary nor possible to exhaustively list all possible implementations. However, obvious variations or modifications derived therefrom are still within the scope of protection of this application.

Claims

1. A configuration method for a power grid embedded DC transmission system, characterized in that, include: Step S1: Construct an embedded DC evaluation system based on the power system safety and stability operation criteria. The evaluation system includes: the first stage is to determine whether all configurable point schemes in the target grid meet the safety requirements based on the power system safety and stability operation criteria; the second stage is to analyze the mid-level indicators of economy, static stability, and dynamic stability, as well as the bottom-level evaluation indicators corresponding to each mid-level indicator, for the schemes that meet the safety requirements of the first stage, and construct a set of embedded DC configuration schemes based on the regional operation characteristics. Step S2: Calculate the power system safety and stability operation index values ​​of each embedded DC configuration scheme in the first stage, and preliminarily screen out the embedded DC channel candidate schemes that meet the power system safety requirements based on the safety and stability operation index values. Step S3: Calculate the underlying index values ​​of the economy, static stability, and dynamic stability of the embedded DC channel alternative schemes that meet the first stage security requirements in the second stage. Calculate the comprehensive superiority score of each embedded DC channel alternative scheme based on the analytic hierarchy process (AHP). Arrange the scores in descending order to determine the optimal addressing scheme.

2. The method according to claim 1, characterized in that, In step S1, the parameters used to determine whether all configurable point schemes in the target grid meet the safety requirements include: the static stability reserve coefficient Kp calculated according to the power angle criterion, the static stability reserve coefficient Kv calculated according to the reactive voltage criterion, the frequency deviation during normal operation of the power system, the sum of the absolute values ​​of positive and negative voltage deviations, and the N-1 verification index. The underlying indicators of the economic indicators include: investment cost and network loss indicators; The underlying indicators of the static stability index include: power flow balance, cross-sectional transmission capacity improvement ratio, static voltage stability L index, embedded DC multi-infeed short-circuit ratio deviation index, and embedded DC sending-end and receiving-end short-circuit ratio. The underlying indicators of the dynamic stability index include: power angle severity index, transient voltage recovery speed, maximum rate of change of transient frequency, and commutation failure immunity factor.

3. The method according to claim 1, characterized in that, In step S1, a set of embedded DC configuration schemes based on partitioned operation characteristics is constructed, including: Based on the characteristics and voltage levels of different zones within the target grid, nodes are selected within each zone as candidate embedding points for the sending or receiving ends of the embedded DC channel. Different candidate embedding points are then combined to form an embedded DC configuration scheme, creating a scheme matrix. In the formula, The matrix consisting of all alternative solutions; For the first One sender alternative embedding point and the first The alternative scheme is composed of a number of alternative embedding points at the receiving end; This represents the total number of alternative embedding points for the sending end. This represents the total number of candidate embedding points at the receiving end. matrix Arrange them in rows sequentially into 1 row. Column matrix : In the formula, A matrix consisting of all the alternative configurations of embedded DC channels in the target network structure; Indicates the first One embedded DC channel alternative configuration option; An overview of alternative configuration options for embedded DC-DC channels, and .

4. The method according to claim 2, characterized in that, In step S2, the formulas for calculating the static stability reserve coefficients Kp and Kv are as follows: The expression for the static stability reserve coefficient calculated according to the work angle criterion is as follows: In the formula, For the first Static stability reserve coefficient calculated based on the power angle criterion under one alternative scheme; For the first The static stability limit power under each alternative scheme, that is, the maximum transmission power of the entire system; This refers to the transmission power during normal system operation. This represents the total number of alternative options. The expression for the static stability reserve coefficient calculated according to the reactive voltage criterion is as follows: In the formula, For the first The first alternative plan The static stability reserve coefficient of each busbar is calculated based on the reactive voltage criterion. For the first The target network structure under the alternative scheme is the first one Normal voltage of the busbar; For the first The target network structure under the alternative scheme is the first one Critical voltage value of a single busbar; For the first The static stability reserve coefficient calculated based on the reactive power voltage criterion under the 1st alternative scheme represents the 1st... The minimum static stability reserve coefficient of all buses in the target grid under the alternative scheme, calculated according to the reactive voltage criterion; This represents the total number of alternative options. The total number of voltage buses in the target grid structure; In step S2, the embedded DC channel alternative scheme is determined to meet the power system security requirements based on the following constraints and N-1 verification indicators: In the formula, For the first Static stability reserve coefficient calculated based on the work angle criterion under one alternative scheme. Greater than or equal to 15% and less than or equal to 20%; For the first Static stability reserve coefficient calculated based on reactive power and voltage criteria under one alternative scheme. Greater than or equal to 10% and less than or equal to 15%; For the first Frequency deviation values ​​under each alternative scheme; For the first The first alternative plan The positive and negative deviation values ​​of the voltage of each busbar; For the first The first alternative plan Rated voltage of the busbar; This represents the total number of alternative options. This represents the total number of voltage buses in the target grid structure.

5. The method according to claim 4, characterized in that, In step S2, after initially screening out the embedded DC channel alternatives that meet the power system security requirements, a new matrix is ​​constructed: In the formula, A matrix consisting of all embedded DC channel alternative configuration schemes that meet the constraints of the first stage of power system safe and stable operation; This represents the l-th embedded DC channel alternative configuration that satisfies the first-stage constraints; This represents the total number of alternative solutions that satisfy the first-stage constraints.

6. The method according to claim 2, characterized in that, In step S3, the underlying indicators of the economic indicators are calculated, including: The expression for investment cost is: In the formula, Let l be the investment cost of the l-th alternative that has met the first-stage constraints; The one-time investment cost of new equipment for the l-th alternative scheme that has met the first-stage constraints; The annual operating and maintenance cost of the new equipment for the l-th alternative scheme that has met the first stage constraints; The land cost of the l-th alternative that has met the first-stage constraints; This represents the total number of all alternative solutions that satisfy the first-stage constraints. The expression for the network loss indicator is: In the formula, The network loss index is the l-th alternative scheme that has met the first-stage constraints; Let be the active power of the l-th alternative that has met the first-stage constraints; Let be the active power of the l-th alternative that has met the first-stage constraints; Let be the active power of the l-th alternative scheme that has met the first-stage constraints; Let l be the capacity base value of the l-th alternative that has met the first-stage constraints; This represents the total number of alternative solutions that satisfy the first-stage constraints.

7. The method according to claim 2, characterized in that, In step S3, the underlying index of the static stability index is calculated, including: The expression for the power flow balance is: In the formula, Let l represent the weighted power flow entropy of the l-th alternative that has met the first-stage constraints; Let be the constant coefficient of the l-th alternative that has satisfied the first-stage constraints; The transmission line load factor in the target transmission section of the l-th alternative scheme that has met the first-stage constraints. The corresponding weighting coefficients; For the l-th alternative scheme that has met the first-stage constraints, the transmission line load factor in the target transmission section is... The corresponding probability coefficient; The total number of transmission lines in the target transmission section; This represents the total number of all alternative solutions that satisfy the first-stage constraints. The expression for the cross-sectional transmission capacity enhancement ratio is: In the formula, The cross-sectional transmission capacity enhancement ratio of the l-th alternative scheme that has met the first stage constraints; , The transmission capacity of the transmission section before and after construction for the first and second embedded DC alternative schemes that have met the first stage constraints, respectively; This represents the total number of all alternative solutions that satisfy the first-stage constraints. The expression for the static voltage stability index L is: In the formula, This represents the l-th alternative solution that has satisfied the first-stage constraints. matrix; Let be the load node self-admittance matrix of the l-th alternative scheme that has met the first-stage constraints; Let be the load node mutual admittance matrix of the l-th alternative scheme that has met the first stage constraints; For the l-th alternative solution that has already met the first-stage constraints, the... Local static voltage stability index of each load node; Let be the complex voltage of the c-th generator node under the l-th alternative scheme that has met the first-stage constraints; For the l-th alternative solution that has already met the first-stage constraints, the... Complex voltage of each load node; Let be the load participation factor for the l-th alternative that has met the first-stage constraints. The first of the matrix Line number Column elements; The static voltage stability index is given by the l-th alternative scheme that has met the first-stage constraints. This represents the total number of load nodes. This represents the total number of all alternative solutions that satisfy the first-stage constraints. This represents the total number of generator nodes. The expression for the embedded DC multi-infeed short-circuit ratio deviation index is as follows: In the formula, The embedded DC multi-infeed short-circuit ratio deviation index represents the l-th alternative scheme that has met the first-stage constraints. This represents the average multi-infeed short-circuit ratio within the target area before configuring the target embedded DC transmission channel; This indicates that after the configuration of the l-th embedded DC transmission channel that has met the first-stage constraints is completed, the number of inputs fed into the multi-infeed AC / DC system is... Multiple feed-in short-circuit ratio at each DC landing port; Indicates the first input in a multi-input AC / DC system Multiple feed-in short-circuit ratio at each DC landing port; Indicates converter station Short-circuit capacity at the location; and These are the rated transmission capacities of the DC system; For converter bus voltage change Time-commutating bus The change in voltage; This represents the total number of all alternative solutions that satisfy the first-stage constraints. This represents the total number of DC landing ports fed into a multi-infeed AC / DC system. The total number of DC lines fed into a multi-infeed AC / DC system; The underlying metrics for calculating the dynamic stability index include: The expression for the power angle severity index is: In the formula, The power angle severity index is the l-th alternative scheme that has met the first stage constraints. , These are the times when a three-phase short-circuit fault occurs on the busbar of the transmission section under the l-th alternative scheme that has met the first stage constraints, respectively, and the times when the maximum and minimum power angles in the system are respectively. This represents the total number of all alternative solutions that satisfy the first-stage constraints. The expression for the transient voltage recovery rate is: In the formula, The transient voltage recovery rate of the l-th alternative scheme that has met the first stage constraints; The moment when a three-phase short-circuit fault occurs on the busbar of the transmission section under the l-th alternative scheme that has met the first stage constraints; The moment when the voltage recovers to 90% of the pre-fault steady-state value after a three-phase short-circuit fault occurs on the busbar of the transmission section under the l-th alternative scheme that has met the first stage constraints; This represents the total number of all alternative solutions that satisfy the first-stage constraints. The expression for the maximum rate of change of the transient frequency is: In the formula, Let l be the maximum rate of change of transient frequency of the l-th alternative that has met the first-stage constraints; , These are the start time of a three-phase short-circuit fault occurring on the busbar of the transmission section under the l-th alternative scheme that has met the first-stage constraints, and the time when the frequency drops to the minimum value after the fault occurs. , For the l-th alternative solution that has already satisfied the first-stage constraints, under the condition that... and Any two moments between; , These are the frequency values ​​when a three-phase short-circuit fault occurs on the busbar of the transmission section under the l-th alternative scheme that has met the first-stage constraints, and the minimum frequency value after the fault occurs, respectively. , For the l-th alternative solution that has satisfied the first-stage constraints, respectively under the following conditions , Frequency value at any given time; This represents the total number of all alternative solutions that satisfy the first-stage constraints. The expression for the phase-switching failure immune factor is: In the formula, The DC commutation failure immune factor index for the l-th alternative scheme that has met the first stage constraints; The rated voltage value of the AC bus of the l-th alternative scheme that has met the first stage constraint conditions; The rated active power of the l-th alternative that has met the first stage constraints; Let be the impedance that causes commutation failure for the l-th alternative scheme that has met the first-stage constraints; This represents the total number of alternative solutions that satisfy the first-stage constraints.

8. The method according to claim 2, characterized in that, In step S3, the specific steps for calculating the overall superiority score based on the analytic hierarchy process include: Step S31: For the mid-level indicators of economy, static stability, and dynamic stability, and their corresponding bottom-level indicators, construct judgment moments using an importance scale of 1-9; Step S32: Calculate the maximum eigenvalue λmax of the judgment matrix, and verify consistency using the consistency ratio. When the consistency ratio... When <0.1, the decision matrix satisfies the consistency requirement; Step S33: When the judgment matrix satisfies the consistency requirement, normalize the eigenvector corresponding to the largest eigenvalue of the judgment matrix to obtain the weight vector. The expression for the judgment matrix B is: In the formula, This serves as a scale for the relative importance of three intermediate-level indicators—economic efficiency, static stability, and dynamic stability—or, respectively, the underlying indicators corresponding to these three intermediate-level indicators. , hour, ; , , , ; for and The relative importance scaling function between them; To determine the order of a matrix; The consistency ratio The expression is as follows: In the formula, To determine the largest eigenvalue of a matrix ; To determine the order of a matrix; The average random consistency index is obtained by constructing multiple sample matrices using random methods and then performing a series of calculations. It is only related to the order of the judgment matrix. Related, When the value is 1-9, the corresponding They are respectively , , , , , , , , When the consistency ratio If the value is less than 0.1, perform the following steps; otherwise, adjust the judgment matrix to satisfy the consistency check. The expression for the weight vector Z is: In the formula, These are the weights of the three mid-level indicators—economic efficiency, static stability, and dynamic stability—or the corresponding bottom-level indicators in the 1st, 2nd, ..., dth, ..., Qth embedded DC channel alternative configuration schemes that have met the first-stage constraints.

9. The method according to claim 2, characterized in that, In step S3, the expression for calculating the comprehensive superiority score is: In the formula, Indicates rating, This represents the indicator value after positive transformation and standardization within the same level; The optimal addressing scheme identification includes: Construct a comprehensive superiority scoring matrix O. In the formula, They are respectively the 1st, 2nd, ..., 1st ,...,No. The overall superiority score of the embedded DC channel alternative configuration scheme that has met the first stage constraints; The elements in the result matrix are sorted in descending order, and the maximum value is selected. The configuration scheme corresponding to the maximum value is the embedded DC configuration scheme that meets the requirements for safe and stable operation of the first stage power system and has the highest overall superiority.

10. A power grid embedded DC transmission system configuration device, characterized in that, include: The evaluation system construction module is used to construct an embedded DC evaluation system based on the criteria for safe and stable operation of the power system. The evaluation system includes a first stage and a second stage. The operation index calculation module, which is connected to the evaluation system construction module, is used to calculate the power system safety and stability operation index values ​​of each embedded DC configuration scheme in the first stage, and to preliminarily screen out the embedded DC channel candidate schemes that meet the power system safety requirements based on the safety and stability operation index values. The underlying index calculation module is connected to the evaluation system construction module and the operation index calculation module, respectively. It is used to calculate the underlying index values ​​of the economy, static stability and dynamic stability of the embedded DC channel alternative scheme that meets the first stage security requirements in the second stage. Based on the analytic hierarchy process, it calculates the comprehensive superiority score of each embedded DC channel alternative scheme, and determines the optimal addressing scheme after arranging the scores in descending order.

Images