Evaluation method, device and equipment of newly-added direct current access configuration and storage medium

Abstract

The application discloses a kind of evaluation methods, device, equipment and storage medium of newly added direct current access configuration, it is related to power system planning and operation control technical field, can intuitively and accurately measure the voltage support intensity of each newly added direct current access configuration to two kinds of weak nodes, provide scientific and quantitative basis for the selection decision of access configuration.The method comprises: constructing receiving-end power grid simulation model, receiving-end power grid simulation model is used to identify the first weak node and the second weak node of receiving-end power grid;According to the candidate drop point position and candidate topology type of newly added direct current setting, form the access configuration scheme set of newly added direct current;Each access configuration scheme in the access configuration scheme set of newly added direct current is applied to receiving-end power grid simulation model respectively, to calculate the voltage support quantitative index of access configuration scheme;According to the voltage support quantitative index of access configuration scheme, the access configuration scheme of corresponding newly added current is comprehensively evaluated, and the evaluation result of access configuration scheme is obtained.

Description

Technical Field

[0001] This application relates to the field of power system planning and operation control technology, and in particular to an evaluation method, apparatus, equipment and storage medium for a newly added DC access configuration. Background Technology

[0002] With the deepening of my country's energy transition, the installed capacity of new energy sources, represented by wind and solar power, continues to grow, and the power system exhibits the "dual high" characteristics of a high proportion of renewable energy and a high proportion of power electronic equipment. As the core carrier for the consumption of clean energy from outside the region and the integration of local new energy sources, the ultra-high-voltage direct current (UHVDC) receiving-end grid needs to undertake the task of feeding in large-scale inter-regional clean energy while facing the challenge of a continuously rising local new energy penetration rate. This change in power structure profoundly affects the voltage stability of the receiving-end grid.

[0003] To meet the growing regional load demand and the requirements for renewable energy consumption, the receiving-end UHVDC power grid still needs to plan for new inter-regional DC transmission channels. Ideally, the new DC transmission lines should not only be power transmission carriers but also active regulatory resources to improve the voltage stability of the receiving-end power grid, directly determining the actual effect on grid voltage support. Therefore, it is necessary to evaluate the configuration of new DC transmission lines.

[0004] In related technologies, thermal stability constraints and static safety verification are the core objectives of new DC transmission planning, which can verify the feasibility of the scheme after the new DC transmission is connected. The short-circuit ratio, as a classic indicator of the AC system's ability to support DC transmission, plays a crucial role in providing a quantitative basis for the aforementioned safety verification. Specifically, by calculating the ratio of the converter bus short-circuit capacity to the DC rated power, it determines whether the system strength in the affected area is sufficient to support the stable operation of the DC system, thereby verifying whether the planning scheme meets core safety requirements such as static voltage stability, ensuring that the new DC transmission can reliably complete its power transmission task. However, in complex scenarios with multiple DC feeds and a high proportion of renewable energy grid connection, this approach lacks a quantitative assessment of the new DC transmission configuration, cannot provide effective support for the quantitative optimization of the new DC transmission configuration, and is even less effective in improving the voltage support strength of the receiving-end grid through new DC transmission planning. Summary of the Invention

[0005] In view of this, this application provides an evaluation method, apparatus, device and storage medium for new DC access configurations. The main purpose is to solve the problem that existing evaluation methods for new current access configurations lack quantitative evaluation of new DC access configurations and cannot provide effective support for the quantitative optimization of new DC access configurations.

[0006] According to the first aspect of this application, an evaluation method for newly added DC access configurations is provided, comprising: A receiving-end power grid simulation model is constructed. The receiving-end power grid simulation model is used to identify the first weak node and the second weak node of the receiving-end power grid. The first weak node is a power grid node with weak voltage support, and the second weak node is a bus node with weak voltage support. Based on the candidate landing point locations and candidate topology types of the newly added DC transmission lines, a set of access configuration schemes for the new DC transmission lines is formed. Each of the newly added DC access configuration schemes is applied to the receiving-end power grid simulation model to calculate the voltage support quantification index of the access configuration scheme. The voltage support quantification index includes the voltage support quantification index of the access configuration scheme for the first weak node and the voltage support quantification index of the access configuration scheme for the second weak node. The access configuration scheme with corresponding new current is comprehensively evaluated based on the voltage support quantification index of the access configuration scheme, and the evaluation result of the access configuration scheme is obtained.

[0007] Furthermore, the step of applying each access configuration scheme in the newly added DC access configuration scheme set to the receiving-end power grid simulation model to calculate the voltage support quantification index of the access configuration scheme includes: Each of the newly added DC access configuration schemes is applied to the receiving-end power grid simulation model to calculate the voltage stiffness improvement index and transient voltage recovery speed index of the access configuration scheme for the first weak node. Each of the newly added DC access configuration schemes is applied to the receiving-end power grid simulation model to calculate the voltage stiffness improvement index and transient voltage recovery speed index of the access configuration scheme for the second weak node.

[0008] Furthermore, the step of applying each access configuration scheme in the newly added DC access configuration scheme set to the receiving-end power grid simulation model to calculate the voltage stiffness improvement index and transient voltage recovery speed index of the access configuration scheme for the first weak node includes: Each access configuration scheme of the newly added DC power grid is applied to the receiving-end power grid simulation model to calculate the change in voltage stiffness of the first weak node in the receiving-end power grid before and after the new DC power grid is added, so as to obtain the voltage stiffness improvement index of the first weak node by the access configuration scheme. Each access configuration scheme of the newly added DC power grid is applied to the receiving-end power grid simulation model to calculate the transient voltage recovery speed index of the first weak node of the access configuration scheme based on the voltage recovery curve of the first weak node in the receiving-end power grid before and after the new DC power grid access. Specifically, the voltage recovery curve of the first weak node before and after the addition of DC access is simulated at the three-phase short-circuit fault in the receiving-end power grid. Based on the voltage recovery curve of the first weak node before and after the addition of DC access, the reciprocal of the time required for the voltage to recover from the fault clearing time to the preset safety threshold is determined as the transient voltage recovery speed index of the first weak node for the access configuration scheme.

[0009] Furthermore, the step of applying each access configuration scheme in the newly added DC access configuration scheme set to the receiving-end power grid simulation model to calculate the voltage stiffness improvement index and transient voltage recovery speed index of the access configuration scheme for the second weak node includes: Each access configuration scheme of the newly added DC power grid is applied to the receiving-end power grid simulation model to calculate the change in voltage stiffness of the second weak node in the receiving-end power grid before and after the addition of DC power grid, so as to obtain the voltage stiffness improvement index of the second weak node by the access configuration scheme. Each access configuration scheme of the newly added DC power grid is applied to the receiving-end power grid simulation model to calculate the transient voltage recovery speed index of the second weak node of the access configuration scheme based on the voltage recovery curve of the second weak node in the receiving-end power grid before and after the new DC power grid access. Specifically, the voltage recovery curve of the second weak node before and after the addition of DC access is simulated at the three-phase short-circuit fault in the receiving-end power grid. Based on the voltage recovery curve of the second weak node before and after the addition of DC access, the reciprocal of the time required for the voltage to recover from the fault clearing time to the preset safety threshold is determined as the transient voltage recovery speed index of the second weak node for the access configuration scheme.

[0010] Furthermore, the voltage stiffness is the ratio of the operating voltage magnitude to the no-load voltage magnitude of the node, specifically expressed by the following formula:

[0011] in, For voltage stiffness, This refers to the operating voltage after the node is connected to the device. The no-load voltage of the node. The equivalent resistance of the connected device. This is the Thevenin equivalent resistance of the power grid as seen from the node.

[0012] The voltage recovery curve is expressed by the following formula:

[0013] in, The voltage recovery curve for the node is shown. This is the time required for the voltage to recover to a preset safety threshold from the moment the fault is cleared.

[0014] Furthermore, before comprehensively evaluating the access configuration scheme for the corresponding new current based on the voltage support quantification index of the access configuration scheme to obtain the evaluation result of the access configuration scheme, the method further includes: A judgment matrix is ​​constructed based on a pre-established hierarchical structure, and the relative importance of each level of indicators is assigned through the judgment matrix to obtain the weight vector of each level of indicators. Accordingly, the comprehensive evaluation of the access configuration scheme for the corresponding new current based on the voltage support quantification index of the access configuration scheme, to obtain the evaluation result of the access configuration scheme, includes: The voltage support quantification index of the access configuration scheme is weighted and calculated using the weight vector of each level index to obtain the index weighted value of the access configuration scheme; The access configuration scheme for the corresponding new current is comprehensively evaluated based on the weighted values ​​of the indicators of the access configuration scheme, and the evaluation result of the access configuration scheme is obtained.

[0015] Furthermore, the step of forming a set of access configuration schemes for the new DC transmission line based on the candidate landing point locations and candidate topology types includes: For each newly added DC current, at least one candidate landing point location should be specified. Different DC topologies are matched for each candidate landing point to form a set of access configuration schemes for the new DC.

[0016] According to a second aspect of this application, an evaluation apparatus for adding a DC access configuration is provided, comprising: A construction unit is used to construct a receiving-end power grid simulation model. The receiving-end power grid simulation model is used to identify the first weak node and the second weak node of the receiving-end power grid. The first weak node is a power grid node with weak voltage support, and the second weak node is a bus node with weak voltage support. The generation unit is used to form a set of access configuration schemes for the new DC based on the candidate landing point locations and candidate topology types of the new DC. The calculation unit is used to apply each access configuration scheme of the newly added DC access configuration scheme to the receiving end power grid simulation model to calculate the voltage support quantification index of the access configuration scheme. The voltage support quantification index includes the voltage support quantification index of the access configuration scheme for the first weak node and the voltage support quantification index of the access configuration scheme for the second weak node. The evaluation unit is used to comprehensively evaluate the access configuration scheme with corresponding new current based on the voltage support quantification index of the access configuration scheme, and obtain the evaluation result of the access configuration scheme.

[0017] Furthermore, the computing unit includes: The first calculation module is used to apply each access configuration scheme of the newly added DC access configuration scheme to the receiving end power grid simulation model to calculate the voltage stiffness improvement index and transient voltage recovery speed index of the access configuration scheme for the first weak node. The second calculation module is used to apply each access configuration scheme of the newly added DC access configuration scheme to the receiving-end power grid simulation model to calculate the voltage stiffness improvement index and transient voltage recovery speed index of the access configuration scheme for the second weak node.

[0018] Furthermore, the first computing module is specifically used for: Each access configuration scheme of the newly added DC power grid is applied to the receiving-end power grid simulation model to calculate the change in voltage stiffness of the first weak node in the receiving-end power grid before and after the new DC power grid is added, so as to obtain the voltage stiffness improvement index of the first weak node by the access configuration scheme. Each access configuration scheme of the newly added DC power grid is applied to the receiving-end power grid simulation model to calculate the transient voltage recovery speed index of the first weak node of the access configuration scheme based on the voltage recovery curve of the first weak node in the receiving-end power grid before and after the new DC power grid access. Specifically, the voltage recovery curve of the first weak node before and after the addition of DC access is simulated at the three-phase short-circuit fault in the receiving-end power grid. Based on the voltage recovery curve of the first weak node before and after the addition of DC access, the reciprocal of the time required for the voltage to recover from the fault clearing time to the preset safety threshold is determined as the transient voltage recovery speed index of the first weak node for the access configuration scheme.

[0019] Furthermore, the second computing module is specifically used for: Each access configuration scheme of the newly added DC power grid is applied to the receiving-end power grid simulation model to calculate the change in voltage stiffness of the second weak node in the receiving-end power grid before and after the addition of DC power grid, so as to obtain the voltage stiffness improvement index of the second weak node by the access configuration scheme. Each access configuration scheme of the newly added DC power grid is applied to the receiving-end power grid simulation model to calculate the transient voltage recovery speed index of the second weak node of the access configuration scheme based on the voltage recovery curve of the second weak node in the receiving-end power grid before and after the new DC power grid access. Specifically, the voltage recovery curve of the second weak node before and after the addition of DC access is simulated at the three-phase short-circuit fault in the receiving-end power grid. Based on the voltage recovery curve of the second weak node before and after the addition of DC access, the reciprocal of the time required for the voltage to recover from the fault clearing time to the preset safety threshold is determined as the transient voltage recovery speed index of the second weak node for the access configuration scheme.

[0020] Furthermore, the voltage stiffness is the ratio of the operating voltage magnitude to the no-load voltage magnitude of the node, specifically expressed by the following formula:

[0021] in, For voltage stiffness, This refers to the operating voltage after the node is connected to the device. The no-load voltage of the node. The equivalent resistance of the connected device. This is the Thevenin equivalent resistance of the power grid as seen from the node.

[0022] The voltage recovery curve is expressed by the following formula:

[0023] in, The voltage recovery curve for the node is shown. This is the time required for the voltage to recover to a preset safety threshold from the moment the fault is cleared.

[0024] Furthermore, the device also includes: The assignment unit is used to construct a judgment matrix based on a pre-established hierarchical structure before comprehensively evaluating the access configuration scheme for the corresponding new current according to the voltage support quantification index of the access configuration scheme and obtaining the evaluation result of the access configuration scheme. The judgment matrix is ​​used to assign values ​​to the relative importance of each level index and obtain the weight vector of each level index. Accordingly, the evaluation unit is specifically used for: The voltage support quantification index of the access configuration scheme is weighted and calculated using the weight vector of each level index to obtain the index weighted value of the access configuration scheme; The access configuration scheme for the corresponding new current is comprehensively evaluated based on the weighted values ​​of the indicators of the access configuration scheme, and the evaluation result of the access configuration scheme is obtained.

[0025] Furthermore, the generating unit is specifically used for: For each newly added DC current, at least one candidate landing point location should be specified. Different DC topologies are matched for each candidate landing point to form a set of access configuration schemes for the new DC.

[0026] According to a third aspect of this application, a computer device is provided, including a memory and a processor, wherein the memory stores a computer program, and the processor executes the computer program to implement the steps of the method described in the first aspect above.

[0027] According to a fourth aspect of this application, a readable storage medium is provided having a computer program stored thereon, which, when executed by a processor, implements the steps of the method described in the first aspect above.

[0028] By employing the above technical solution, this application provides an evaluation method, apparatus, device, and storage medium for new DC access configurations. Compared with the existing technology that uses thermal stability constraints and static safety checks to evaluate new DC access configurations, this application constructs a receiving-end power grid simulation model. This model identifies the first and second weak nodes of the receiving-end power grid. The first weak node is a grid node with weak voltage support, and the second weak node is a bus node with weak voltage support. Based on the candidate landing point location and candidate topology type of the new DC connection, a set of access configuration schemes for the new DC connection is formed. Each access configuration scheme in the set is applied to the receiving-end power grid simulation model to calculate the voltage support quantification index of the access configuration scheme. The voltage support quantification index includes the voltage support quantification index of the access configuration scheme for the first weak node and the voltage support quantification index of the access configuration scheme for the second weak node. Based on the voltage support quantification index of the access configuration scheme, the corresponding access configuration scheme for the new current is comprehensively evaluated to obtain the evaluation result of the access configuration scheme. Throughout the evaluation process of the new DC access configuration, the dual voltage support requirements of the new DC for the first and second weak nodes are comprehensively considered. Quantitative voltage support indicators are calculated for the two types of weak nodes, enabling a precise quantitative comparison of the support effects of different access configuration schemes. The numerical differences in the building quantitative indicators can intuitively and accurately measure the voltage support strength of each new DC access configuration for the two types of weak nodes, providing a scientific and quantitative basis for the selection decision of the access configuration. This effectively overcomes the shortcomings of traditional planning methods in quantifying and evaluating the support effects of access configurations.

[0029] The above description is only an overview of the technical solution of this application. In order to better understand the technical means of this application and to implement it in accordance with the contents of the specification, and to make the above and other objects, features and advantages of this application more obvious and understandable, specific embodiments of this application are given below. Attached Figure Description

[0030] The accompanying drawings, which are included to provide a further understanding of this application and form part of this application, illustrate exemplary embodiments and are used to explain this application, but do not constitute an undue limitation of this application. In the drawings: Figure 1 This is a flowchart illustrating the evaluation method for a newly added DC access configuration in one embodiment of this application; Figure 2 yes Figure 1 A flowchart illustrating a specific implementation method for step 103; Figure 3 This is a flowchart illustrating the evaluation method for adding a DC access configuration in another embodiment of this application; Figure 4 yes Figure 1 A flowchart illustrating a specific implementation method for step 102; Figure 5 This is a schematic diagram of the structure of the evaluation device for the newly added DC access configuration in one embodiment of this application; Figure 6 This is a schematic diagram of the device structure of a computer device provided in an embodiment of the present invention. Detailed Implementation

[0031] The invention will now be discussed with reference to several exemplary embodiments. It should be understood that these embodiments are described merely to enable those skilled in the art to better understand and thus implement the invention, and are not intended to imply any limitation on the scope of the invention.

[0032] As used herein, the term "comprising" and its variations are to be interpreted as open-ended terms meaning "including but not limited to". The term "based on" is to be interpreted as "at least partially based on". The terms "one embodiment" and "an embodiment" are to be interpreted as "at least one embodiment". The term "another embodiment" is to be interpreted as "at least one other embodiment".

[0033] In related technologies, thermal stability constraints and static safety verification are the core objectives of new DC transmission planning, which can verify the feasibility of the scheme after the new DC transmission is connected. The short-circuit ratio, as a classic indicator of the AC system's ability to support DC transmission, plays a crucial role in providing a quantitative basis for the aforementioned safety verification. Specifically, by calculating the ratio of the converter bus short-circuit capacity to the DC rated power, it determines whether the system strength in the affected area is sufficient to support the stable operation of the DC system, thereby verifying whether the planning scheme meets core safety requirements such as static voltage stability, ensuring that the new DC transmission can reliably complete its power transmission task. However, in complex scenarios with multiple DC feeds and a high proportion of renewable energy grid connection, this approach lacks a quantitative assessment of the new DC transmission configuration, cannot provide effective support for the quantitative optimization of the new DC transmission configuration, and is even less effective in improving the voltage support strength of the receiving-end grid through new DC transmission planning.

[0034] To address this issue, this embodiment provides an evaluation method for newly added DC access configurations, such as... Figure 1 As shown, it includes the following steps: 101. Construct a simulation model of the receiving-end power grid.

[0035] The receiving-end power grid simulation model is a digital model used to construct power system simulation algorithms, capable of reproducing the actual operating characteristics of the receiving-end power grid. Specifically, the receiving-end power grid simulation model is used to identify the first and second weak nodes of the receiving-end power grid. The first weak node is a grid node with weak voltage support, and the second weak node is a bus node with weak voltage support.

[0036] The specific receiving-end power grid simulation model can be built based on power system simulation software. In the evaluation scenario of newly added DC access configuration, the receiving-end power grid simulation model includes at least the power grid topology, power source units, load units, and a simulation operating condition set. The power grid topology includes the connection relationships of AC lines, transformers, buses, and load nodes, as well as parameters such as impedance and capacity of each component. Power source units include synchronous generators, new energy generators, and existing DC power. Load units include the active / reactive power values ​​and load types of each node. The simulation operating condition set includes steady-state operating conditions and fault operating conditions.

[0037] In this embodiment, the receiving-end power grid simulation model can accurately locate the first and second weak nodes through power flow calculation and / or N-1 fault scanning. Specifically, steady-state operating conditions are set based on the actual operating scenarios of the receiving-end power grid. Power flow calculations are run in the receiving-end power grid simulation model, and the steady-state voltage amplitude and voltage deviation rate of all nodes in the model are output. Based on the set voltage deviation rate threshold, candidate nodes with excessive voltage deviation rates are screened. Based on the functional attributes of the candidate nodes, they are initially divided into first candidate weak nodes and second candidate weak nodes. Then, for the key components of the receiving-end power grid, the fault of single component out of operation is simulated one by one. For example, important transmission lines in the model are disconnected one by one to simulate AC line N-1 faults, and key transformer equipment such as main transformers are disconnected to simulate transformer N-1 faults. For each N-1 fault scenario, the power flow redistribution result of the power grid after the fault is calculated, and the voltage amplitude and voltage recovery capability of the first and second candidate weak nodes after the fault are determined. Finally, the first weak node that meets the set conditions is screened based on the voltage amplitude and voltage recovery capability of the first candidate weak node after the fault, and the second candidate weak node that meets the set conditions is screened based on the voltage amplitude and voltage recovery capability of the second candidate weak node after the fault.

[0038] 102. Based on the candidate landing point locations and candidate topology types of the newly added DC, form a set of access configuration schemes for the newly added DC.

[0039] In this embodiment, the candidate landing point location refers to the hub bus or converter station site in the receiving-end power grid that has the conditions for adding DC power. Its selection does not depend on the weak node identification results, but is determined solely based on the power grid topology characteristics, engineering implementation conditions, and power absorption requirements. Hub buses with high voltage levels and large short-circuit capacity are given priority. These buses are the junction points of multiple transmission lines, which can efficiently accept the new DC power and distribute it to the entire network, avoiding local power flow overload or voltage fluctuations.

[0040] In this embodiment, the candidate topology type refers to the mainstream transmission topology that can be used for the new current, including but not limited to conventional DC topology and flexible DC topology. Here, conventional DC topology is based on thyristor converter valves, which rely on AC grid voltage to achieve commutation and has a simple control method; flexible DC topology is based on modular multilevel converter valves, which have self-commutation capability and can independently control active / reactive power.

[0041] 103. Apply each of the newly added DC access configuration schemes to the receiving-end power grid simulation model to calculate the voltage support quantification index of the access configuration scheme.

[0042] In this embodiment, the voltage support quantification index includes the voltage support quantification index of the access configuration scheme for the first weak node and the voltage support quantification index of the access configuration scheme for the second weak node. Specifically, after applying each access configuration scheme of the newly added DC access configuration scheme to the receiving-end power grid simulation model, the steady-state operating condition and N-1 fault operating condition simulations are repeatedly run for each access configuration scheme. The real-time operating parameters of the two types of weak nodes in each access configuration scheme are output. Based on the real-time operating parameters of the two types of weak nodes in each access configuration scheme, the voltage support quantification index of the access configuration scheme is calculated. Here, the voltage support quantification index is a quantifiable numerical parameter used to objectively measure the improvement effect of the access scheme on the voltage support capability of the two types of weak nodes, and it needs to be calculated separately for the first weak node and the second weak node. The voltage support quantification index includes at least the voltage stiffness improvement index and the transient voltage recovery speed index.

[0043] The aforementioned voltage stiffness improvement index is used to measure the degree to which a node's ability to resist voltage fluctuations is improved after the addition of a new DC line. In other words, the stronger the voltage stiffness, the smaller the impact of load or power fluctuations on the node voltage.

[0044] Specifically, in the process of calculating the voltage support quantification index of the access configuration scheme, the reduction rate of voltage-power sensitivity can be used to quantify the stiffness improvement effect. For the first weak node and the second weak node, the voltage-power sensitivity coefficient before the addition of DC access and the voltage-power sensitivity coefficient after the addition of DC access are obtained respectively. The voltage-power sensitivity coefficient before the addition of DC access is used as a benchmark parameter and compared with the voltage-power sensitivity coefficient after the addition of DC access. The voltage stiffness improvement index of the access configuration scheme for the first weak node and the voltage stiffness improvement index of the access configuration scheme for the second weak node are obtained through the comparison results.

[0045] It should be noted that, for the voltage stiffness improvement index, the calculation logic of the voltage stiffness improvement index of the first weak node and the voltage stiffness improvement index of the second weak node is similar. Both are quantified by the reduction rate of the voltage-power sensitivity coefficient, and follow the same calculation steps and formulas. However, due to the different functional characteristics of the two types of nodes, parameter acquisition and operating condition configuration need to match the node attributes.

[0046] The aforementioned transient voltage recovery rate index is used to measure the rate at which the voltage of a node recovers to a safe threshold after the N-1 fault is cleared following the connection of a new DC line.

[0047] Specifically, in the process of calculating the voltage support quantification index of the access configuration scheme, the improvement effect of recovery speed can be quantified by the reduction rate of voltage recovery time. For the first weak node and the second weak node, the first recovery time after the fault before the addition of DC access and the second recovery time after the fault after the addition of DC access are obtained respectively. The first recovery time is used as a benchmark parameter and compared with the second recovery time to obtain the transient voltage recovery speed index of the access configuration scheme for the first weak node and the transient voltage recovery speed index of the access configuration scheme for the second weak node.

[0048] For conventional DC topologies, existing DC transmission systems exhibit constant power load characteristics under steady state. Adding new DC connections will not reduce the Thevenin equivalent impedance and may even reduce voltage stiffness due to reactive power consumption. For flexible DC topologies, however, flexible DC transmission systems employ constant AC voltage control, exhibiting ideal voltage source characteristics. When calculating the Thevenin equivalent impedance, the flexible DC transmission system is equivalent to having a very small impedance connected in parallel, significantly reducing the system's Thevenin equivalent impedance and bringing the voltage stiffness close to 1. Calculation results show that the connection configuration scheme using a flexible DC topology is significantly superior to the connection configuration scheme using a conventional DC topology in improving voltage stiffness in AC weak point regions.

[0049] 104. Based on the voltage support quantification index of the access configuration scheme, a comprehensive evaluation of the corresponding new current access configuration scheme is conducted to obtain the evaluation result of the access configuration scheme.

[0050] In this embodiment, the voltage support quantification index of the access configuration scheme for the first weak node and the voltage support quantification index of the access configuration scheme for the second weak node can be formed into an evaluation parameter pool. First, invalid access configuration schemes are screened out by setting a threshold to avoid wasting evaluation resources on inefficient schemes. Then, weights are allocated according to the priority of the impact of the voltage support quantification index on power grid security. The voltage support quantification index of the access configuration scheme is weighted and calculated according to the allocated weights to obtain the evaluation result of the access configuration scheme.

[0051] Accordingly, the optimal access configuration scheme is selected based on the evaluation results of the access configuration scheme, serving as the basis for the implementation of new DC projects. Based on the candidate landing points in the optimal access configuration scheme, the address, land acquisition, and transmission channel path planning of the converter station are carried out. Based on the topology type structure in the optimal access configuration scheme, the selection, control, and strategy parameters of the converter valve are determined. Combined with the indicator improvement effect, the grid connection parameters of the converter station and the receiving end power grid are optimized.

[0052] The evaluation method for new DC access configurations provided in this application differs from existing technologies that use thermal stability constraints and static safety checks. This application constructs a receiving-end power grid simulation model to identify the first and second weak nodes in the receiving-end power grid. The first weak node is a grid node with weak voltage support, and the second weak node is a bus node with weak voltage support. Based on the candidate landing point locations and candidate topology types of the new DC connection, a set of access configuration schemes for the new DC connection is formed. Each access configuration scheme in the set is applied to the receiving-end power grid simulation model to calculate the voltage support quantification index of the access configuration scheme. The voltage support quantification index includes the voltage support quantification index of the access configuration scheme for the first weak node and the voltage support quantification index of the access configuration scheme for the second weak node. A comprehensive evaluation of the corresponding new current access configuration scheme is performed based on the voltage support quantification index of the access configuration scheme to obtain the evaluation result of the access configuration scheme. Throughout the evaluation process of the new DC access configuration, the dual voltage support requirements of the new DC for the first and second weak nodes are comprehensively considered. Quantitative voltage support indicators are calculated for the two types of weak nodes, enabling a precise quantitative comparison of the support effects of different access configuration schemes. The numerical differences in the building quantitative indicators can intuitively and accurately measure the voltage support strength of each new DC access configuration for the two types of weak nodes, providing a scientific and quantitative basis for the selection decision of the access configuration. This effectively overcomes the shortcomings of traditional planning methods in quantifying and evaluating the support effects of access configurations.

[0053] In the above embodiments, the access configuration scheme set is essentially a combination of different DC landing point locations and topology types. Different combinations show significant differences in their support effects on the two types of weak nodes. For example, conventional DC topologies provide better support for weak grids than flexible DC topologies, and landing point locations closer to weak nodes offer better support than those farther away. To accurately quantify the support effects of the access configuration schemes on the two types of weak nodes, specifically, as follows... Figure 2 As shown, step 103 includes the following steps: 201. Apply each of the newly added DC access configuration schemes to the receiving-end power grid simulation model to calculate the voltage stiffness improvement index and transient voltage recovery speed index of the access configuration scheme for the first weak node.

[0054] 202. Apply each of the newly added DC access configuration schemes to the receiving-end power grid simulation model to calculate the voltage stiffness improvement index and transient voltage recovery speed index of the access configuration scheme for the second weak node.

[0055] In this embodiment, the voltage stiffness enhancement index is used to reflect the sensitivity of node voltage to power fluctuations, and its calculation requires accurate simulation of steady-state power flow. For the first weak node, each access configuration scheme in the set of new DC access schemes can be applied to the receiving-end power grid simulation model to calculate the change in voltage stiffness of the first weak node in the receiving-end power grid before and after the new DC access, thus obtaining the voltage stiffness enhancement index of the access configuration scheme for the first weak node. For the second weak node, each access configuration scheme in the set of new DC access schemes can be applied to the receiving-end power grid simulation model to calculate the change in voltage stiffness of the second weak node in the receiving-end power grid before and after the new DC access, thus obtaining the voltage stiffness enhancement index of the access configuration scheme for the second weak node.

[0056] The voltage stiffness mentioned above is the ratio of the operating voltage magnitude to the no-load voltage magnitude of the node, specifically expressed by the following formula:

[0057] in, For voltage stiffness, This refers to the operating voltage after the node is connected to the device. The no-load voltage of the node. The equivalent resistance of the connected device. This is the Thevenin equivalent resistance of the power grid as seen from the node.

[0058] Understandably, in the planning and design of new DC transmission lines connecting to the receiving-end power grid, it is necessary to accurately assess the voltage support effect of different connection configuration schemes on weak nodes in the power grid, in order to precisely define the mechanism of action of different connection configuration schemes on weak nodes in the receiving-end power grid, as follows: When a new DC power source adopts a flexible DC topology, if the flexible DC system operates in a constant AC voltage control mode or a constant reactive power control mode, it is equivalent to a voltage source in terms of electrical characteristics. This equivalent voltage source has the ability to actively adjust the amplitude and phase of the output voltage. After connecting it to the receiving-end grid, it can significantly reduce the Thevenin equivalent impedance of weak nodes in the receiving-end grid and improve the node voltage support strength.

[0059] When a new DC power source adopts a conventional DC topology, the commutation process of the conventional DC system depends on the AC voltage of the receiving-end grid. In terms of electrical characteristics, it is equivalent to a constant power load or current source. This equivalent load / current source does not have active voltage regulation capability, and its output power or current remains basically constant. After being connected to the receiving-end grid, it mainly absorbs or injects grid power. Its effect on improving the voltage support capability of weak nodes in the receiving-end grid is weaker than that of a flexible DC topology.

[0060] In this embodiment, the transient voltage recovery rate index is used to reflect the recovery speed of the node voltage after a fault. Its calculation requires capturing the transient evolution process of the voltage after the fault is cleared. For the first weak node, each access configuration scheme in the set of new DC access configuration schemes can be applied to the receiving-end power grid simulation model to calculate the transient voltage recovery rate index of the access configuration scheme for the first weak node based on the voltage recovery curve of the first weak node in the receiving-end power grid before and after the new DC access. Accordingly, specifically at the three-phase short-circuit fault location set in the receiving-end power grid, the voltage recovery curve of the first weak node before and after the new DC access is simulated; based on the voltage recovery curve of the first weak node before and after the new DC access, the reciprocal of the time required for the voltage to recover from the fault clearing time to the preset safety threshold is determined as the transient voltage recovery rate index of the access configuration scheme for the first weak node. For the second weak node, each access configuration scheme in the set of new DC access configuration schemes can be applied to the receiving-end power grid simulation model to calculate the transient voltage recovery rate index of the access configuration scheme for the second weak node based on the voltage recovery curve of the second weak node in the receiving-end power grid before and after the new DC access. Accordingly, the voltage recovery curve of the second weak node before and after the addition of DC access is simulated at the three-phase short-circuit fault location in the receiving-end power grid. Based on the voltage recovery curve of the second weak node before and after the addition of DC access, the reciprocal of the time required for the voltage to recover from the fault clearance time to the preset safety threshold is determined as the transient voltage recovery speed index of the second weak node for the access configuration scheme.

[0061] The voltage recovery curve described above is expressed by the following formula:

[0062] in, The voltage recovery curve for the node is shown. This is the time required for the voltage to recover to a preset safety threshold from the moment the fault is cleared.

[0063] The fault location can be selected from the critical transmission line near the weak node. When a short-circuit fault occurs at this location, the impact on the voltage of the weak node is most significant, which can fully expose the transient voltage stability problem of the node. The fault duration can be set to 0.15s, and the fault clearing method can be set to tripping the faulty line. It should be noted that in the process of calculating the voltage recovery curve of the weak node before and after the addition of DC access, the fault location, fault type, duration, and fault clearing method must be kept completely consistent. At the same time, the basic parameters such as grid power output and load level should be kept unchanged, and only the configuration scheme of the added DC access should be changed.

[0064] The horizontal axis of the voltage recovery curve represents the time after the fault is cleared (in seconds), and the vertical axis represents the voltage amplitude of the weak node (in pu). This voltage recovery curve can intuitively reflect the evolution process of the node voltage recovering from the fault drop state to a safe level.

[0065] It is understandable that the essence of transient voltage recovery speed is the rate at which the reactive power deficit of the power grid is filled after a fault. The rapid dynamic reactive power support of the flexible DC transmission system can directly shorten the response time of reactive power compensation, thus theoretically shortening the voltage recovery time.

[0066] In practical applications, the voltage stiffness improvement index of the converter bus in an existing DC transmission system characterizes the bus's ability to withstand power fluctuations. Its core parameter is the voltage-power sensitivity coefficient; a smaller value indicates stronger voltage stiffness. Therefore, when calculating the voltage stiffness improvement index after adding a new DC line, the interactive effects between multiple DC lines must be considered. Specifically, for the converter bus of an existing DC transmission system, the change in voltage stiffness after adding a new DC line is calculated. When the new DC line uses a flexible DC topology and its electrical distance is relatively short, the voltage stiffness of the existing DC transmission system's converter bus can be improved through the dynamic reactive power support provided by the flexible DC transmission system, reducing the risk of commutation failure in the existing DC transmission system.

[0067] In practical applications, when the candidate landing point is electrically close to the landing point of the existing target DC transmission system, and the flexible DC transmission system can provide strong voltage support, adding a new DC connection will increase the voltage stiffness of the existing target DC transmission system bus, greatly enhancing its ability to withstand commutation failure. In particular, areas where the existing target DC transmission system is located have low short-circuit capacity and have historically experienced commutation failures, thus being identified as weak points in the existing DC system.

[0068] Conversely, if the electrical distance between the landing points of two existing DC transmission systems is relatively close and there is multi-infeed interaction, the risk of commutation failure of the target existing DC transmission system may actually increase, and the voltage stiffness will not improve significantly or may even decrease.

[0069] In practical applications, voltage support quantification indicators exhibit significant hierarchical characteristics, and different indicators have fundamentally different impacts on power grid security. Furthermore, to focus on the voltage support quantification indicators of the access configuration scheme in a hierarchical manner, such as... Figure 3 As shown, prior to step 104, the method further includes the following steps: 301. Construct a judgment matrix based on the pre-established hierarchical structure, and assign values ​​to the relative importance of each level indicator through the judgment matrix to obtain the weight vector of each level indicator.

[0070] Accordingly, step 104 includes the following steps: 302. Using the weight vectors of the indicators at each level, the voltage support quantification indicators of the access configuration scheme are weighted and calculated to obtain the weighted values ​​of the access configuration scheme indicators.

[0071] 303. Based on the weighted values ​​of the indicators of the access configuration scheme, a comprehensive evaluation of the access configuration scheme for the corresponding new current is performed to obtain the evaluation result of the access configuration scheme.

[0072] In this embodiment, the hierarchical structure can be divided into three layers, decomposed layer by layer from top to bottom. Each layer is only responsible for the element above it. Specifically, it includes a target layer, a criterion layer, and an index layer. Among them, the target layer A, as the highest layer, can perform a comprehensive evaluation of the new DC access configuration scheme; the criterion layer B, as the middle layer, can be divided by dimension and includes commutation safety criterion B1, transient support criterion B2, steady-state support criterion B3, and stiffness improvement criterion B4; the index layer C, as the lowest layer, includes specific quantitative indicators under each criterion. For example, the commutation safety criterion B1 corresponds to the commutation failure suppression rate C1 and the commutation overlap angle reduction rate C2; ​​the transient support criterion B2 corresponds to the transient voltage recovery speed index C3, etc.

[0073] Specifically, the hierarchical structure can be transformed into a judgment matrix using the Analytic Hierarchy Process (AHP). First, a judgment matrix is ​​constructed for each level. This judgment matrix is ​​a pairwise comparison matrix of the importance of elements within the same level relative to a certain element in the upper level. For example, using target level A as the comparison criterion, quantitative importance comparisons are performed on calibrated levels B1-B4, converting qualitative importance descriptions into quantitative scaling values. Then, a judgment matrix AB is constructed. Assuming the criterion level has n elements, the judgment matrix AB is an n-order square matrix. Labeling Guidelines Relative to criteria Importance scale value, satisfying .

[0074] For example, the criterion layer contains 4 elements, and the corresponding judgment matrix AB can be represented in the following form:

[0075] Further, each element in the criteria layer For comparison purposes, the importance of each pair of elements C in the indicator layer is compared using the same method as above, and a judgment matrix is ​​constructed for the indicator layer.

[0076] For example, for criterion B1, and for its subordinate indicators C1 and C2, the corresponding judgment matrix B1-C can be represented in the following form:

[0077] Specifically, in the process of assigning relative importance values ​​to indicators at each level through the judgment matrix, the eigenvalue method can be used to perform mathematical calculations on each judgment matrix to obtain the initial weight vector of each level of indicator. After normalization, the final weight vector is obtained. For the calculation of the criterion layer weight vector, the product M of each row element in the judgment matrix can be calculated, and then the nth root of the score M of each row element can be calculated to obtain the initial weight vector. The initial weight vector is then normalized to obtain the criterion layer weight vector. For the calculation of the indicator layer weight vector, the judgment matrix of each indicator layer can be calculated separately to obtain the initial weight matrix corresponding to each indicator layer judgment matrix. After normalization, the local weight vector of the indicator layer under each criterion layer element is obtained. The combined weight vector of the indicator layer is calculated, and the local weight vector of each indicator layer is multiplied by the corresponding criterion layer weight to obtain the combined weight vector of the indicator layer relative to the target layer.

[0078] Furthermore, to ensure the accuracy of the weight vectors for each level of indicators, a consistency check can be performed on each judgment matrix to verify the validity of the weight vectors. This process involves calculating the maximum eigenvalue of each judgment matrix, calculating the consistency index CI based on the maximum eigenvalue, finding the average random consistency index RI corresponding to the matrix order, and calculating the consistency ratio CR = CI / RI. If CR < 0.1, the judgment matrix is ​​considered consistent and the corresponding weight vector is valid. If CR ≥ 0.1, the scale value of the judgment matrix is ​​adjusted, and the steps of constructing the judgment matrix are repeated until the consistency check is passed.

[0079] Correspondingly, by using the weight vectors of indicators at each level to perform weighted calculations on the voltage support quantification indicators of the access configuration scheme, the original set of full-dimensional voltage support quantification indicators obtained from the calculation of the new DC access configuration scheme can be normalized to obtain a set of normalized indicator values. Then, the weighted values ​​of the access configuration scheme are directly obtained by combining the weights of the indicator layers, that is, by directly using the combined weight vector of the indicator layer relative to the target layer and the normalized indicator values ​​to perform weighted summation.

[0080] In practical applications, the grid support capability of a newly added DC transmission line to a weak node in the receiving-end power grid is determined by both the landing point location and the characteristics of the DC topology. To cover all combinations of landing point location and DC topology, a quantitative evaluation is needed to select the optimal access configuration scheme for the new DC transmission line. Specifically, such as... Figure 4 As shown, step 102 above includes the following steps: 401. Set at least one candidate landing point for each newly added DC current.

[0081] 402. Match different DC topologies for each candidate landing point location to form a set of access configuration schemes for the new DC.

[0082] Understandably, the candidate landing point is the specific node where the new DC transmission line is electrically connected to the receiving-end grid. Its setting should consider the following two conditions: one is voltage support requirements. In this case, the candidate landing point needs to be close to a weak node in the receiving-end grid. This weak node can be the first weak node, the AC voltage weak node, the second weak node, or the weak node of the existing DC transmission system converter bus, etc., to ensure that the dynamic reactive power support of the new DC transmission line can be efficiently transmitted to the weak node. The other is power transmission requirements. In this case, the candidate landing point needs to be connected to the main grid structure and have sufficient power flow dissipation capacity to meet the rated power feed-in requirements of the new DC transmission line.

[0083] In this embodiment, combining candidate landing point locations with candidate topology types generates a set of access configuration schemes for the newly added DC power. For each candidate landing point location, different candidate topology types are matched to generate an independent access configuration scheme. For example, if there are M candidate landing points, N candidate topology types, and M access configuration schemes for the newly added DC power, then a new group is formed.

[0084] For example, candidate landing sites are selected from hub substation X near the load center, substation Y near the existing DC transmission system, and substation Z near the renewable energy aggregation point C. For each candidate landing site, conventional DC topology and flexible DC topology are considered respectively, resulting in 3 access configuration schemes for each: Scheme 1: Candidate landing site X + conventional DC topology; Scheme 2: Candidate landing site X + flexible DC topology; Scheme 3: Candidate landing site Y + conventional DC topology; Scheme 4: Candidate landing site Y + flexible DC topology; Scheme 5: Candidate landing site Z + conventional DC topology; Scheme 6: Candidate landing site Z + flexible DC topology.

[0085] Furthermore, as Figure 1-4 In terms of specific implementation, this application provides an evaluation device for newly added DC access configurations, such as... Figure 5 As shown, the device includes: a construction unit 51, a generation unit 52, a calculation unit 53, and an evaluation unit 54.

[0086] Construction unit 51 is used to construct a receiving-end power grid simulation model. The receiving-end power grid simulation model is used to identify the first weak node and the second weak node of the receiving-end power grid. The first weak node is a power grid node with weak voltage support, and the second weak node is a bus node with weak voltage support. The generation unit 52 is used to form a set of access configuration schemes for the new DC based on the candidate landing point location and candidate topology type of the new DC. The calculation unit 53 is used to apply each access configuration scheme of the newly added DC access configuration scheme to the receiving end power grid simulation model to calculate the voltage support quantification index of the access configuration scheme. The voltage support quantification index includes the voltage support quantification index of the access configuration scheme for the first weak node and the voltage support quantification index of the access configuration scheme for the second weak node. Evaluation unit 54 is used to comprehensively evaluate the access configuration scheme with corresponding new current based on the voltage support quantification index of the access configuration scheme, and obtain the evaluation result of the access configuration scheme.

[0087] The evaluation device for newly added DC access configurations provided in this invention, compared with the existing technology that uses thermal stability constraints and static safety checks to evaluate newly added DC access configurations, constructs a receiving-end power grid simulation model. This model identifies the first and second weak nodes of the receiving-end power grid. The first weak node is a grid node with weak voltage support, and the second weak node is a bus node with weak voltage support. Based on the candidate landing point locations and candidate topology types of the newly added DC, a set of access configuration schemes for the newly added DC is formed. Each access configuration scheme in the set is applied to the receiving-end power grid simulation model to calculate the voltage support quantification index of the access configuration scheme. The voltage support quantification index includes the voltage support quantification index of the access configuration scheme for the first weak node and the voltage support quantification index of the access configuration scheme for the second weak node. A comprehensive evaluation of the access configuration scheme for the corresponding newly added current is performed based on the voltage support quantification index of the access configuration scheme to obtain the evaluation result of the access configuration scheme. Throughout the evaluation process of the new DC access configuration, the dual voltage support requirements of the new DC for the first and second weak nodes are comprehensively considered. Quantitative voltage support indicators are calculated for the two types of weak nodes, enabling a precise quantitative comparison of the support effects of different access configuration schemes. The numerical differences in the building quantitative indicators can intuitively and accurately measure the voltage support strength of each new DC access configuration for the two types of weak nodes, providing a scientific and quantitative basis for the selection decision of the access configuration. This effectively overcomes the shortcomings of traditional planning methods in quantifying and evaluating the support effects of access configurations.

[0088] In specific application scenarios, the computing unit includes: The first calculation module is used to apply each access configuration scheme of the newly added DC access configuration scheme to the receiving end power grid simulation model to calculate the voltage stiffness improvement index and transient voltage recovery speed index of the access configuration scheme for the first weak node. The second calculation module is used to apply each access configuration scheme of the newly added DC access configuration scheme to the receiving-end power grid simulation model to calculate the voltage stiffness improvement index and transient voltage recovery speed index of the access configuration scheme for the second weak node.

[0089] In specific application scenarios, the first computing module is specifically used for: Each access configuration scheme of the newly added DC power grid is applied to the receiving-end power grid simulation model to calculate the change in voltage stiffness of the first weak node in the receiving-end power grid before and after the new DC power grid is added, so as to obtain the voltage stiffness improvement index of the first weak node by the access configuration scheme. Each access configuration scheme of the newly added DC power grid is applied to the receiving-end power grid simulation model to calculate the transient voltage recovery speed index of the first weak node of the access configuration scheme based on the voltage recovery curve of the first weak node in the receiving-end power grid before and after the new DC power grid access. Specifically, the voltage recovery curve of the first weak node before and after the addition of DC access is simulated at the three-phase short-circuit fault in the receiving-end power grid. Based on the voltage recovery curve of the first weak node before and after the addition of DC access, the reciprocal of the time required for the voltage to recover from the fault clearing time to the preset safety threshold is determined as the transient voltage recovery speed index of the first weak node for the access configuration scheme.

[0090] In specific application scenarios, the second computing module is further used for: Each access configuration scheme of the newly added DC power grid is applied to the receiving-end power grid simulation model to calculate the change in voltage stiffness of the second weak node in the receiving-end power grid before and after the addition of DC power grid, so as to obtain the voltage stiffness improvement index of the second weak node by the access configuration scheme. Each access configuration scheme of the newly added DC power grid is applied to the receiving-end power grid simulation model to calculate the transient voltage recovery speed index of the second weak node of the access configuration scheme based on the voltage recovery curve of the second weak node in the receiving-end power grid before and after the new DC power grid access. Specifically, the voltage recovery curve of the second weak node before and after the addition of DC access is simulated at the three-phase short-circuit fault in the receiving-end power grid. Based on the voltage recovery curve of the second weak node before and after the addition of DC access, the reciprocal of the time required for the voltage to recover from the fault clearing time to the preset safety threshold is determined as the transient voltage recovery speed index of the second weak node for the access configuration scheme.

[0091] In specific application scenarios, the voltage stiffness is the ratio of the operating voltage magnitude of the node to the no-load voltage magnitude, specifically expressed by the following formula:

[0092] in, For voltage stiffness, This refers to the operating voltage after the node is connected to the device. The no-load voltage of the node. The equivalent resistance of the connected device. This is the Thevenin equivalent resistance of the power grid as seen from the node.

[0093] The voltage recovery curve is expressed by the following formula:

[0094] in, The voltage recovery curve for the node is shown. This is the time required for the voltage to recover to a preset safety threshold from the moment the fault is cleared.

[0095] In specific application scenarios, the device further includes: The assignment unit is used to construct a judgment matrix based on a pre-established hierarchical structure before comprehensively evaluating the access configuration scheme for the corresponding new current according to the voltage support quantification index of the access configuration scheme and obtaining the evaluation result of the access configuration scheme. The judgment matrix is ​​used to assign values ​​to the relative importance of each level index and obtain the weight vector of each level index. Accordingly, the evaluation unit is specifically used for: The voltage support quantification index of the access configuration scheme is weighted and calculated using the weight vector of each level index to obtain the index weighted value of the access configuration scheme; The access configuration scheme for the corresponding new current is comprehensively evaluated based on the weighted values ​​of the indicators of the access configuration scheme, and the evaluation result of the access configuration scheme is obtained.

[0096] In specific application scenarios, the generation unit is specifically used for: For each newly added DC current, at least one candidate landing point location should be specified. Different DC topologies are matched for each candidate landing point to form a set of access configuration schemes for the new DC.

[0097] It should be noted that other corresponding descriptions of the functional units involved in the evaluation device for a newly added DC access configuration provided in this embodiment can be found in [reference needed]. Figures 1-4 The corresponding description in [the document] will not be repeated here.

[0098] Based on the above, Figures 1-4 Accordingly, this application embodiment also provides a storage medium storing a computer program thereon, which, when executed by a processor, implements the above-described method. Figures 1-4 The evaluation method for the newly added DC access configuration is shown.

[0099] Based on this understanding, the technical solution of this application can be embodied in the form of a software product. The software product can be stored in a non-volatile storage medium (such as a CD-ROM, USB flash drive, or portable hard drive), and includes several instructions to cause a computer device (such as a personal computer, server, or network device) to execute the methods described in the various implementation scenarios of this application.

[0100] Based on the above, Figures 1-4 The method shown, and Figure 5To achieve the above objectives, this application also provides a physical device for evaluating a newly added DC access configuration, as illustrated in the virtual device embodiment. Specifically, this physical device can be a computer, smartphone, tablet, smartwatch, server, or network device, etc. The physical device includes a storage medium and a processor; the storage medium stores a computer program; the processor executes the computer program to implement the above-described... Figures 1-4 The evaluation method for the newly added DC access configuration is shown.

[0101] Optionally, the physical device may also include a user interface, a network interface, a camera, radio frequency (RF) circuitry, sensors, audio circuitry, a Wi-Fi module, etc. The user interface may include a display screen, input units such as a keyboard, etc., and optional user interfaces may also include USB interfaces, card reader interfaces, etc. The network interface may optionally include standard wired interfaces, wireless interfaces (such as Wi-Fi interfaces), etc.

[0102] In an exemplary embodiment, see Figure 6 The aforementioned physical device includes a communication bus, a processor, a memory, and a communication interface. It may also include an input / output interface and a display device. The various functional units can communicate with each other via the bus. The memory stores a computer program, and the processor executes the program stored in the memory to perform the evaluation method for the newly added DC access configuration in the above embodiments.

[0103] Those skilled in the art will understand that the physical device structure for evaluating a new DC access configuration provided in this embodiment does not constitute a limitation on the physical device, and may include more or fewer components, or combine certain components, or have different component arrangements.

[0104] The storage medium may also include an operating system and a network communication module. The operating system is a program that manages the hardware and software resources of the physical device used for evaluating the newly added DC access configuration, supporting the operation of information processing programs and other software and / or programs. The network communication module is used to enable communication between the various components within the storage medium, as well as communication with other hardware and software in the information processing physical device.

[0105] Through the above description of the embodiments, those skilled in the art can clearly understand that this application can be implemented by means of software plus necessary general-purpose hardware platforms, or it can be implemented by hardware. By applying the technical solution of this application, compared with the existing methods, this application, in the process of evaluating the new DC access configuration, comprehensively considers the dual voltage support requirements of the new DC for the first weak node and the second weak node, calculates the voltage support quantitative index for the two types of weak nodes respectively, and realizes a precise quantitative comparison of the support effect of different access configuration schemes. The numerical difference of the building quantitative index can intuitively and accurately measure the voltage support strength of each new DC access configuration for the two types of weak nodes, providing a scientific and quantitative basis for the selection decision of access configuration, and effectively overcoming the defect of traditional planning methods that are difficult to quantitatively evaluate the support effect of access configuration.

[0106] Those skilled in the art will understand that the accompanying drawings are merely schematic diagrams of a preferred embodiment, and the modules or processes shown in the drawings are not necessarily essential for implementing this application. Those skilled in the art will understand that the modules in the apparatus of the embodiment can be distributed within the apparatus of the embodiment as described, or can be modified to be located in one or more apparatuses different from this embodiment. The modules of the above-described embodiment can be combined into one module, or further divided into multiple sub-modules.

[0107] The serial numbers in this application are for descriptive purposes only and do not represent the superiority or inferiority of any particular implementation scenario. The above disclosures are merely a few specific implementation scenarios of this application; however, this application is not limited thereto, and any variations conceived by those skilled in the art should fall within the protection scope of this application.

Claims

1. A method for evaluating newly added DC access configurations, characterized in that, include: A receiving-end power grid simulation model is constructed. The receiving-end power grid simulation model is used to identify the first weak node and the second weak node of the receiving-end power grid. The first weak node is a power grid node with weak voltage support, and the second weak node is a bus node with weak voltage support. Based on the candidate landing point locations and candidate topology types of the newly added DC transmission lines, a set of access configuration schemes for the new DC transmission lines is formed. Each of the newly added DC access configuration schemes is applied to the receiving-end power grid simulation model to calculate the voltage support quantification index of the access configuration scheme. The voltage support quantification index includes the voltage support quantification index of the access configuration scheme for the first weak node and the voltage support quantification index of the access configuration scheme for the second weak node. The access configuration scheme with corresponding new current is comprehensively evaluated based on the voltage support quantification index of the access configuration scheme, and the evaluation result of the access configuration scheme is obtained.

2. The method according to claim 1, characterized in that, The step of applying each access configuration scheme from the newly added DC access configuration scheme set to the receiving-end power grid simulation model to calculate the voltage support quantification index of the access configuration scheme includes: Each of the newly added DC access configuration schemes is applied to the receiving-end power grid simulation model to calculate the voltage stiffness improvement index and transient voltage recovery speed index of the access configuration scheme for the first weak node. Each of the newly added DC access configuration schemes is applied to the receiving-end power grid simulation model to calculate the voltage stiffness improvement index and transient voltage recovery speed index of the access configuration scheme for the second weak node.

3. The method according to claim 2, characterized in that, The step of applying each access configuration scheme from the newly added DC access configuration scheme set to the receiving-end power grid simulation model to calculate the voltage stiffness improvement index and transient voltage recovery speed index of the access configuration scheme for the first weak node includes: Each access configuration scheme of the newly added DC power grid is applied to the receiving-end power grid simulation model to calculate the change in voltage stiffness of the first weak node in the receiving-end power grid before and after the new DC power grid is added, so as to obtain the voltage stiffness improvement index of the first weak node by the access configuration scheme. Each access configuration scheme of the newly added DC power grid is applied to the receiving-end power grid simulation model to calculate the transient voltage recovery speed index of the first weak node of the access configuration scheme based on the voltage recovery curve of the first weak node in the receiving-end power grid before and after the new DC power grid access. Specifically, the voltage recovery curve of the first weak node before and after the addition of DC access is simulated at the three-phase short-circuit fault in the receiving-end power grid. Based on the voltage recovery curve of the first weak node before and after the addition of DC access, the reciprocal of the time required for the voltage to recover from the fault clearing time to the preset safety threshold is determined as the transient voltage recovery speed index of the first weak node for the access configuration scheme.

4. The method according to claim 3, characterized in that, The step of applying each access configuration scheme from the newly added DC access configuration scheme set to the receiving-end power grid simulation model to calculate the voltage stiffness improvement index and transient voltage recovery speed index of the access configuration scheme for the second weak node includes: Each access configuration scheme of the newly added DC power grid is applied to the receiving-end power grid simulation model to calculate the change in voltage stiffness of the second weak node in the receiving-end power grid before and after the addition of DC power grid, so as to obtain the voltage stiffness improvement index of the second weak node by the access configuration scheme. Each access configuration scheme of the newly added DC power grid is applied to the receiving-end power grid simulation model to calculate the transient voltage recovery speed index of the second weak node of the access configuration scheme based on the voltage recovery curve of the second weak node in the receiving-end power grid before and after the new DC power grid access. Specifically, the voltage recovery curve of the second weak node before and after the addition of DC access is simulated at the three-phase short-circuit fault in the receiving-end power grid. Based on the voltage recovery curve of the second weak node before and after the addition of DC access, the reciprocal of the time required for the voltage to recover from the fault clearing time to the preset safety threshold is determined as the transient voltage recovery speed index of the second weak node for the access configuration scheme.

5. The method according to claim 3, characterized in that, The voltage stiffness is the ratio of the operating voltage magnitude to the no-load voltage magnitude of the node, specifically expressed by the following formula: in, For voltage stiffness, This refers to the operating voltage after the node is connected to the device. The no-load voltage of the node. The equivalent resistance of the connected device. This is the Thevenin equivalent resistance of the power grid as seen from the node. The voltage recovery curve is expressed by the following formula: in, The voltage recovery curve for the node is shown. This is the time required for the voltage to recover to a preset safety threshold from the moment the fault is cleared.

6. The method according to any one of claims 1-5, characterized in that, Before comprehensively evaluating the access configuration scheme for the corresponding new current based on the voltage support quantification index of the access configuration scheme to obtain the evaluation result of the access configuration scheme, the method further includes: A judgment matrix is ​​constructed based on a pre-established hierarchical structure, and the relative importance of each level of indicators is assigned through the judgment matrix to obtain the weight vector of each level of indicators. Accordingly, the comprehensive evaluation of the access configuration scheme for the corresponding new current based on the voltage support quantification index of the access configuration scheme, to obtain the evaluation result of the access configuration scheme, includes: The voltage support quantification index of the access configuration scheme is weighted and calculated using the weight vector of each level index to obtain the index weighted value of the access configuration scheme; The access configuration scheme for the corresponding new current is comprehensively evaluated based on the weighted values ​​of the indicators of the access configuration scheme, and the evaluation result of the access configuration scheme is obtained.

7. The method according to any one of claims 1-5, characterized in that, The process of forming a set of access configuration schemes for the new DC transmission line based on the candidate landing point locations and candidate topology types includes: For each newly added DC current, at least one candidate landing point location should be specified. Different DC topologies are matched for each candidate landing point to form a set of access configuration schemes for the new DC.

8. An evaluation device for newly added DC access configuration, characterized in that, include: A construction unit is used to construct a receiving-end power grid simulation model. The receiving-end power grid simulation model is used to identify the first weak node and the second weak node of the receiving-end power grid. The first weak node is a power grid node with weak voltage support, and the second weak node is a bus node with weak voltage support. The generation unit is used to form a set of access configuration schemes for the new DC based on the candidate landing point locations and candidate topology types of the new DC. The calculation unit is used to apply each access configuration scheme of the newly added DC access configuration scheme to the receiving end power grid simulation model to calculate the voltage support quantification index of the access configuration scheme. The voltage support quantification index includes the voltage support quantification index of the access configuration scheme for the first weak node and the voltage support quantification index of the access configuration scheme for the second weak node. The evaluation unit is used to comprehensively evaluate the access configuration scheme with corresponding new current based on the voltage support quantification index of the access configuration scheme, and obtain the evaluation result of the access configuration scheme.

9. A computer device comprising a memory and a processor, wherein the memory stores a computer program, characterized in that, When the processor executes the computer program, it implements the steps of the evaluation method for the newly added DC access configuration as described in any one of claims 1 to 7.

10. A computer-readable storage medium having a computer program stored thereon, characterized in that, When the computer program is executed by the processor, it implements the steps of the evaluation method for the newly added DC access configuration as described in any one of claims 1 to 7.

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