A power distribution network carrying capacity evaluation method, device, equipment and storage medium

Abstract

The application provides a power distribution network carrying capacity evaluation method, device, equipment and storage medium. In the method, the line carrying capacity is evaluated to obtain a first evaluation result; the carrying capacity of the transformer equipment is evaluated to obtain a second evaluation result; based on the upper and lower level relationship sequence of the line and the transformer, the first evaluation result and the second evaluation result, the carrying capacity of the multi-level distributed power supply in the region is corrected to determine a third evaluation result; and based on the third evaluation result, the evaluation result of the carrying capacity of the distributed power supply of all regions of the power distribution network and the carrying capacity level of all regions of the power distribution network is determined. It can be seen that the above method not only considers modeling and calculation of the carrying capacity of each level of transformer and line, but also considers the mutual influence of the carrying capacity between different voltage level devices and lines, and performs data correction, so that the carrying capacity of all regions of the power distribution network can be better determined, and the accuracy of the evaluation result of the carrying capacity of the power distribution network is improved.

Description

Technical Field

[0001] This application belongs to the field of power grid technology, and in particular relates to a method, apparatus, equipment and storage medium for evaluating the carrying capacity of a distribution network. Background Technology

[0002] A distribution network refers to a power grid that receives electrical energy from the transmission network or regional power plants and distributes it locally or tiered according to voltage to various users through distribution facilities. It consists of overhead lines, cables, poles, distribution transformers, disconnect switches, reactive power compensators, and some auxiliary facilities, playing a crucial role in distributing electrical energy within the power grid. The carrying capacity of the distribution network is the fundamental basis for the planning, operation, maintenance, and upgrading of new distribution networks.

[0003] Currently, the carrying capacity of distribution networks is only modeled based on the thermal stability and power quality of power grid equipment. The carrying capacity of distributed power source access points is only evaluated at a single level of equipment in the power grid. This makes the evaluation results of the carrying capacity of distribution networks rather vague and inaccurate. Summary of the Invention

[0004] In view of this, the purpose of this application is to provide a method, apparatus, equipment and storage medium for assessing the carrying capacity of a power distribution network, so as to improve the accuracy of the assessment results of the carrying capacity of the power distribution network.

[0005] Firstly, this application provides a method for assessing the carrying capacity of a distribution network, comprising:

[0006] Based on the preset relationship between the installed capacity of lines and power sources at different voltage levels, the node voltage constraints of the distribution network, the power flow constraints of the line branches of the distribution network, and the line capacity constraints of the distribution network, the carrying capacity of lines at different voltage levels in all areas of the distribution network is evaluated to obtain the first evaluation result corresponding to the lines at different voltage levels in the area.

[0007] The carrying capacity of transformer equipment at different voltage levels is evaluated based on the output coefficient of distributed power sources, the rated capacity of transformer equipment at different voltage levels, and the total load carried by transformer equipment at different voltage levels, so as to obtain the second evaluation results corresponding to transformer equipment at different voltage levels in the region.

[0008] Based on the hierarchical relationship between lines and transformers, the first evaluation result, and the second evaluation result, the carrying capacity of multi-level distributed power sources in the region is corrected, and the third evaluation result is determined.

[0009] Based on the third assessment results, the distributed power carrying capacity of all areas of the distribution network is determined;

[0010] Based on the third assessment results, the carrying capacity level of the distribution network is determined.

[0011] Optionally, the node voltage constraint equations of the distribution network are as follows:

[0012] V i，min ≤V i，t ≤V i，max

[0013] V i，min V is the lower voltage limit for the safe operation of node i in the distribution network, where i is any node in the distribution network. i，max V is the upper limit of voltage for safe operation of node i of the power distribution line. i，t Let represent the voltage at node i at time t, where t is any arbitrary time point.

[0014] Optionally, the power flow constraint equations for the line branches of the distribution network are as follows:

[0015] V j，t =V i，t -(r ij P ij，t +X ij Q ij，t )

[0016] Among them, V j，t V represents the voltage at node j at time t. i，t P represents the voltage at node i of the power distribution line at time t. ij，t r represents the active power flowing through branch ij at time point t. ij x represents the resistance of branch ij. ij Q represents the resistance of branch ij. ij，t This represents the reactive power flowing through branch ij at time point t.

[0017] Optionally, the line capacity constraint equations of the distribution network are as follows:

[0018]

[0019] Among them, P ij，t Q represents the active power flowing through branch ij at time point t. ij，t S represents the reactive power flowing through branch ij at time point t. ij This indicates the line capacity of branch ij.

[0020] Optionally, the voltage level of the transformer equipment is 220kV, and the second evaluation result can be calculated according to the following formula:

[0021]

[0022] If the voltage level of the transformer equipment is other than 220kV, the second evaluation result can be calculated according to the following formula.

[0023]

[0024] Among them, S DG Adding capacity to distributed power sources, whereby the added capacity represents the second evaluation result corresponding to the transformer equipment, k t S represents the output factor of distributed generation. N Rated capacity of transformer equipment λ represents the total load carried by the transformer equipment, and λ represents the reverse load rate after the distributed power source is connected.

[0025] Optionally, the process of correcting the multi-level distributed power carrying capacity within the region based on the hierarchical relationship between lines and transformers, the first evaluation result, and the second evaluation result, and determining the third evaluation result, includes:

[0026] Compare the second evaluation result corresponding to the transformer equipment at the first voltage level with the first evaluation result corresponding to the line below the first voltage level. If the second evaluation result corresponding to the transformer equipment at the first voltage level is larger, then determine the first evaluation result corresponding to the line below the first voltage level as the third evaluation result corresponding to the line below the first voltage level in the multi-level distributed power carrying capacity.

[0027] If the second evaluation result corresponding to the transformer equipment at the first voltage level is small, then the first evaluation result corresponding to the line at the lower voltage level is adjusted, and the adjusted first evaluation result is used as the third evaluation result corresponding to the line at the lower voltage level in the multi-level distributed power carrying capacity.

[0028] Compare the first evaluation results corresponding to the second voltage level line with the second evaluation results corresponding to the transformer equipment of the second voltage level;

[0029] If the first evaluation result corresponding to the second voltage level line is large, then the first evaluation result corresponding to the second voltage level transformer is determined to be the third evaluation result corresponding to the second voltage level transformer in the multi-level distributed power carrying capacity.

[0030] If the first evaluation result corresponding to the second voltage level line is small, then the second evaluation result corresponding to the transformer equipment of the second voltage level is adjusted, and the first evaluation result corresponding to the second voltage level line is used as the second evaluation result corresponding to the transformer equipment of the second voltage level in the multi-level distributed power carrying capacity.

[0031] Secondly, this application provides an assessment device for the carrying capacity of a distribution network, comprising:

[0032] The first evaluation unit is used to evaluate the line carrying capacity of different voltage levels in all areas of the distribution network according to the preset relationship between the line and the power supply installed capacity of different voltage levels, the node voltage constraints of the distribution network, the line branch power flow constraints of the distribution network, and the line capacity constraints of the distribution network, so as to obtain the first evaluation result corresponding to the line of different voltage levels in the area.

[0033] The second evaluation unit is used to evaluate the carrying capacity of transformer equipment at different voltage levels based on the output coefficient of distributed power sources, the rated capacity of transformer equipment at different voltage levels, and the total load carried by transformer equipment at different voltage levels, so as to obtain the second evaluation results corresponding to transformer equipment at different voltage levels in the region.

[0034] The first determining unit is used to determine the third evaluation result corresponding to the multi-level distributed power carrying capacity in the region based on the hierarchical relationship between the lines and transformers, the first evaluation result, and the second evaluation result.

[0035] The second determining unit is used to determine the distributed power carrying capacity of all areas of the distribution network based on the third evaluation result.

[0036] The third determining unit is used to determine the carrying capacity level of the distribution network based on the third evaluation result.

[0037] Thirdly, this application provides an assessment device for the carrying capacity of a power distribution network, comprising:

[0038] Memory, used to store computer programs;

[0039] A processor for executing a computer program stored in the memory to implement the steps of the method for assessing the carrying capacity of a distribution network as described in any of the first aspects.

[0040] Fourthly, this application provides a computer-readable storage medium storing a computer program that is executed by a processor to implement the steps of the method for assessing the carrying capacity of a distribution network as described in any of the first aspects.

[0041] As can be seen, this application discloses a method, apparatus, equipment, and storage medium for assessing the carrying capacity of a distribution network. In this method, the carrying capacity of lines is assessed based on the preset relationship between the installed capacity of lines and power sources at different voltage levels, the node voltage constraints of the distribution network, the power flow constraints of the line branches of the distribution network, and the line capacity constraints of the distribution network, yielding a first assessment result. The carrying capacity of transformer equipment is assessed based on the output coefficient of distributed power sources, the rated capacity of transformer equipment at different voltage levels, and the total load carried by transformer equipment at different voltage levels, yielding a second assessment result. Based on the hierarchical relationship between lines and transformers, the first assessment result, and the second assessment result, the carrying capacity of multi-level distributed power sources within the region is corrected to determine a third assessment result. Based on the third assessment result, the carrying capacity of distributed power sources in all areas of the distribution network and the assessment results of the carrying capacity levels of all areas of the distribution network are determined. It is evident that the above method not only considers modeling and calculating the carrying capacity of transformers and lines at each level but also considers the mutual influence of carrying capacity between equipment and lines at different voltage levels and performs data correction, thereby enabling a better determination of the carrying capacity of all areas of the distribution network and improving the accuracy of the assessment results of the distribution network carrying capacity. Attached Figure Description

[0042] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0043] Figure 1 This is a flowchart illustrating a method for assessing the carrying capacity of a power distribution network according to an embodiment of this application.

[0044] Figure 2 This is a schematic diagram of the structure of a power distribution network carrying capacity assessment device provided in an embodiment of this application. Detailed Implementation

[0045] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0046] To facilitate understanding of the technical solutions provided in this application, the background technology involved in this application will be explained below.

[0047] Currently, the carrying capacity of distribution networks is only modeled based on the thermal stability and power quality of power grid equipment. The carrying capacity of distributed power source access points is only evaluated at a single level of equipment in the power grid. This makes the evaluation results of the carrying capacity of distribution networks rather vague and inaccurate.

[0048] Therefore, this application discloses a method, apparatus, equipment, and storage medium for assessing the carrying capacity of a distribution network. In this method, the carrying capacity of lines is assessed based on the preset relationship between the installed capacity of lines and power sources at different voltage levels, the node voltage constraints of the distribution network, the power flow constraints of the line branches of the distribution network, and the line capacity constraints of the distribution network, yielding a first assessment result. The carrying capacity of transformer equipment is assessed based on the output coefficient of distributed power sources, the rated capacity of transformer equipment at different voltage levels, and the total load carried by transformer equipment at different voltage levels, yielding a second assessment result. Based on the hierarchical relationship between lines and transformers, the first assessment result, and the second assessment result, the carrying capacity of multi-level distributed power sources within the region is corrected, determining a third assessment result. Based on the third assessment result, the carrying capacity of distributed power sources in certain areas of the distribution network and the assessment results for the carrying capacity levels of all areas of the distribution network are determined. It is evident that the above method not only considers modeling and calculating the carrying capacity of transformers and lines at each level but also considers the mutual influence of carrying capacity between equipment and lines at different voltage levels and performs data correction, thereby better determining the carrying capacity of all areas of the distribution network and improving the accuracy of the assessment results for the carrying capacity of the distribution network.

[0049] To facilitate understanding of the technical solution provided in this application, the following description, in conjunction with the accompanying drawings, will explain a method for evaluating the carrying capacity of a power distribution network.

[0050] See Figure 1 This figure is a flowchart illustrating a method for evaluating the carrying capacity of a power distribution network according to an embodiment of this application. Figure 1 As shown, the method includes S101-S105.

[0051] S101: Based on the preset relationship between the installed capacity of lines and power sources at different voltage levels, the node voltage constraints of the distribution network, the power flow constraints of the line branches of the distribution network, and the line capacity constraints of the distribution network, the carrying capacity of lines at different voltage levels in all areas of the distribution network is evaluated to obtain the first evaluation result corresponding to the lines at different voltage levels in the area.

[0052] It is understood that a power distribution network can include multiple power distribution lines. The following example illustrates the solution proposed in this application by showing a connection of a single power distribution line: 220kV transformer - 110kV line - 110kV transformer - 35kV line - 35kV transformer - 10kV line.

[0053] As mentioned above, the voltage levels of power lines can be divided into 110kV lines, 35kV lines, and 10kV lines. It is understood that the preset relationships between different voltage levels of power lines and their installed power capacity include those for 110kV lines, 35kV lines, and 10kV lines. Depending on the needs, the initial installed power capacity of different voltage levels of power lines can be determined first. In this embodiment, the initial installed power capacity of the power lines is determined based on the preset relationships between different voltage levels of power lines and their installed power capacity. Then, the initial installed power capacity is adjusted based on the node voltage constraints, branch power flow constraints, and line capacity constraints of the distribution network, thereby determining the carrying capacity of different voltage levels of power lines, and this carrying capacity is used as the first evaluation result.

[0054] This application does not limit the specific parameters for assessing the carrying capacity of the distribution network. As an example, this application assesses the carrying capacity of the distribution network based on source-grid-load interaction data. The source data includes the power generation of wind power and photovoltaic power in the distribution network area; the grid data includes grid equipment data; and the load data includes load data for the distribution network area. It is understood that the source-grid-load data includes the archived data and operational data of the distribution network equipment, and it is dynamically changing.

[0055] This application does not limit the specific method of node voltage constraint in the distribution network. As one possible implementation, the node voltage constraint equation of the distribution network is as follows:

[0056] V i，min ≤V i，t ≤V i，max (1)

[0057] V i，min V is the lower voltage limit for the safe operation of node i in the distribution network, where i is any node in the distribution network. i，max V is the upper limit of voltage for safe operation of node i of the power distribution line. i，t Let represent the voltage at node i at time t, where t is any arbitrary time point.

[0058] This application does not limit the specific method of node voltage constraint in the distribution network. As one possible implementation, the power flow constraint equations for the line branches of the distribution network are as follows:

[0059] Vj，t =V i，t -(r ij P ij，t +x ij Q ij，t (2)

[0060] Among them, V j，t V represents the voltage at node j at time t. i，t P represents the voltage at node i of the power distribution line at time t. ij，t r represents the active power flowing through branch ij at time point t. ij x represents the resistance of branch ij. ij Q represents the resistance of branch ij. ij，t This represents the reactive power flowing through branch ij at time point t.

[0061] This application does not limit the specific method of node voltage constraint in the distribution network. As one possible implementation, the line capacity constraint equation of the distribution network is as follows:

[0062]

[0063] Among them, P ij，t Q represents the active power flowing through branch ij at time point t. ij，t S represents the reactive power flowing through branch ij at time point t. ij This indicates the line capacity of branch ij.

[0064] It is understandable that the installed power supply capacity is equivalent to the line's carrying capacity. Based on the above constraint equations, the installed power supply capacity can be adjusted to obtain the maximum value that makes the above inequality true, thereby determining the carrying capacity of lines at different voltage levels, and using this carrying capacity as the first evaluation result.

[0065] S102: The carrying capacity of transformer equipment at different voltage levels is evaluated based on the output coefficient of distributed power sources, the rated capacity of transformer equipment at different voltage levels, and the total load carried by transformer equipment at different voltage levels, to obtain the second evaluation results corresponding to transformer equipment at different voltage levels in the region.

[0066] In this embodiment, the load-bearing capacity of transformers at different voltage levels will also be evaluated based on the output factor of the distributed power source, the rated capacity of transformers at different voltage levels, and the total load carried by transformers at different voltage levels. It is understood that the output factor of the distributed power source, the rated capacity of the transformers, and the total load carried by the transformers can be obtained based on actual operating conditions.

[0067] As one possible implementation, if the voltage level of the transformer equipment is 220kV, the second evaluation result is calculated according to the following formula:

[0068]

[0069] Among them, S DG Adding capacity to distributed power sources, whereby the added capacity represents the second evaluation result corresponding to the transformer equipment, k t S represents the output factor of distributed generation. N Rated capacity of transformer equipment λ represents the total load carried by the transformer equipment, and λ represents the reverse load rate after the distributed power source is connected.

[0070] Understandably, the load-bearing capacity of the transformer equipment, i.e., the second assessment result, can be represented by the size of the newly added capacity of distributed power sources. For 220kV transformer equipment, it is necessary to consider that distributed power sources are not allowed to feed back power, so the calculation is based on the maximum reverse load rate being less than 0.

[0071] If the voltage level of the transformer equipment is other than 220kV, the second evaluation result is calculated according to the following formula:

[0072]

[0073] The parameters in the formula are as described above. This application does not limit the specific data for other levels besides 220kV. As one possible implementation, other levels besides 220kV can be 110kV and 35kV.

[0074] For transformer equipment that is not 220kV, distributed power sources are connected to the transformer via dedicated lines. Their carrying capacity is not limited by factors such as line power flow. The main consideration is that the reverse load rate of the equipment after connection should not exceed 80% of the rated load rate of the equipment.

[0075] S103: Based on the hierarchical relationship between lines and transformers, the first evaluation result, and the second evaluation result, the carrying capacity of multi-level distributed power sources in the region is corrected, and the third evaluation result is determined.

[0076] It is understood that in the embodiments of this application, after evaluating the lines and transformers separately to obtain the first evaluation result and the second evaluation result, the evaluation result of the lower-level lines or equipment will be corrected according to the hierarchical relationship between the lines and transformers, using the evaluation result of the upper-level equipment or lines, and the carrying capacity of lines and transformers of different voltage levels in the region will be corrected to obtain the carrying capacity of multi-level distributed power sources in the region and determine the third evaluation result.

[0077] As one possible implementation, based on the hierarchical relationship between lines and transformers, the first evaluation result, and the second evaluation result, the carrying capacity of multi-level distributed power sources within the region is corrected to determine the third evaluation result, including the following steps:

[0078] A1: Compare the second evaluation result corresponding to the transformer equipment at the first voltage level with the first evaluation result corresponding to the line below the first voltage level. If the second evaluation result corresponding to the transformer equipment at the first voltage level is larger, then determine the first evaluation result corresponding to the line below the first voltage level as the third evaluation result corresponding to the line below the first voltage level in the multi-level distributed power supply carrying capacity. If the second evaluation result corresponding to the transformer equipment at the first voltage level is smaller, then adjust the first evaluation result corresponding to the line below the first voltage level, and take the second evaluation result corresponding to the transformer equipment at the first voltage level as the third evaluation result corresponding to the line below the first voltage level in the multi-level distributed power supply carrying capacity.

[0079] In this embodiment, the second evaluation result corresponding to the transformer equipment at the first voltage level is compared with the first evaluation result corresponding to the line at a voltage level lower than the first voltage level. It can be understood that if the transformer equipment is 220kV, the carrying capacity of the 220kV transformer is compared with the sum of the carrying capacities of the 110kV, 35kV, and 10kV lines. Similarly, if the transformer equipment is 110kV, the carrying capacity of the 110kV transformer is compared with the sum of the carrying capacities of the 35kV and 10kV lines. If the transformer equipment is 35kV, the carrying capacity of the 35kV transformer is compared with the sum of the carrying capacities of the 10kV line.

[0080] It is understandable that if the carrying capacity of the 220kV transformer is larger than the sum of the carrying capacities of the 110kV, 35kV, and 10kV lines, then the individual carrying capacities of the 110kV, 35kV, and 10kV lines will be retained as the carrying capacities of the 110kV, 35kV, and 10kV lines in the multi-level distributed power supply.

[0081] If the carrying capacity of a 220kV transformer is smaller than the sum of the carrying capacities of 110kV, 35kV, and 10kV lines, then the carrying capacities of the 110kV, 35kV, and 10kV lines are adjusted respectively, and the carrying capacity of the 220kV transformer is taken as the carrying capacity of the line among the 110kV, 35kV, and 10kV lines that has a higher carrying capacity than the 220kV transformer. Similarly, the 110kV and 35kV transformers can be adjusted in the same way.

[0082] A2: Compare the first evaluation result corresponding to the second voltage level line with the second evaluation result corresponding to the transformer equipment of the second voltage level; if the first evaluation result corresponding to the second voltage level line is larger, then determine the first evaluation result corresponding to the transformer of the second voltage level as the third evaluation result corresponding to the transformer of the second voltage level in the multi-level distributed power carrying capacity; if the first evaluation result corresponding to the second voltage level line is smaller, then adjust the second evaluation result corresponding to the transformer equipment of the second voltage level, and take the first evaluation result corresponding to the second voltage level line as the second evaluation result corresponding to the transformer equipment of the second voltage level in the multi-level distributed power carrying capacity.

[0083] In this embodiment of the application, the first evaluation result corresponding to the second voltage level line is also compared with the second evaluation result of the transformer equipment of the second voltage level. It is understood that the carrying capacity of the 110kV line is compared with the carrying capacity of the 110kV transformer, and the carrying capacity of the 35kV line is also compared with the carrying capacity of the 35kV transformer.

[0084] If the carrying capacity of the 110kV line is greater than that of the 110kV transformer, the carrying capacity of the 110kV transformer will be retained and used as the carrying capacity of the 110kV transformer in the multi-level distributed power supply. If the carrying capacity of the 110kV line is less than that of the 110kV transformer, the carrying capacity of the 110kV transformer will be adjusted, and the carrying capacity of the 110kV line will be used as the adjusted carrying capacity of the 110kV transformer. Similarly, the carrying capacity of the 35kV line can be adjusted in the same way.

[0085] After adjusting the carrying capacity of the lines and transformers according to the above method, the third evaluation result corresponding to the carrying capacity of the multi-level distributed power source can be obtained.

[0086] S104: Based on the third evaluation results, determine the distributed power carrying capacity of all areas of the distribution network.

[0087] In this embodiment of the application, after obtaining the multi-level distributed power carrying capacity within the region, the distributed power carrying capacity of all regions of the distribution network will be determined based on the third evaluation results.

[0088] As one possible implementation, this application embodiment determines the distributed carrying capacity of all areas of the distribution network using the following formula:

[0089] S A =min{∑ i S Ti , ∑ k S Lk};

[0090] Among them, S A S represents the regional distributed power carrying capacity. Ti S represents the load-carrying capacity of the transformer at level i. Lk This represents the carrying capacity of the k-th level line. It is understood that there can be multiple distribution lines within a distribution network area, each with multiple lines and transformers of the same voltage level. This application can sum the carrying capacities of lines / transformers at the same voltage level and compare their magnitudes to obtain the minimum value among the lines / transformers at the same voltage level in different distribution lines, which will be used as the carrying capacity of the entire distribution network area.

[0091] S105: Based on the third assessment results, determine the carrying capacity level of all areas of the distribution network.

[0092] In this embodiment of the application, after obtaining the carrying capacity of the multi-level distributed power sources in the region, the carrying capacity level of the distribution network area will be determined based on the third evaluation results.

[0093] As one possible implementation, the carrying capacity level of all areas of the distribution network is determined based on the third assessment results, including: calculating the reverse load rate based on the third assessment results; and determining the carrying capacity level of all areas of the distribution network based on the reverse load rate.

[0094] The formula for calculating the reverse load rate is:

[0095] Among them, S DG Adding capacity to distributed power sources, whereby the added capacity represents the second evaluation result corresponding to the transformer equipment, k t S represents the output factor of distributed generation. N Rated capacity of transformer equipment λ represents the total load carried by the transformer equipment, and λ represents the reverse load rate after the distributed power source is connected.

[0096] The reverse load rate of transformer equipment at different voltage levels can be calculated using the above formula. The carrying capacity level of all areas of the distribution network can be determined by the magnitude of the reverse load rate.

[0097] As one possible approach, if the voltage level of the transformer equipment is not 220kV, then if the reverse load rate calculated based on the transformer equipment is less than or equal to 0, the carrying capacity level of the distribution network area corresponding to the transformer equipment can be determined as Level 1, and distributed power supply access is recommended.

[0098] Similarly, if the reverse load rate calculated based on the transformer equipment is greater than 0 and less than or equal to 0.8, then the carrying capacity level of the distribution network area corresponding to the transformer equipment is determined to be Level 2, and the access of distributed power sources needs to be investigated.

[0099] If the reverse load rate is greater than 0.8, the carrying capacity level of the distribution network area corresponding to the transformer equipment is determined to be Level 3, and distributed power source access is not recommended.

[0100] If the voltage level of the transformer equipment is 220kV, then if the reverse load rate is greater than 0, the carrying capacity level of the distribution network area corresponding to the transformer equipment is determined to be Level 3, and distributed power supply access is not recommended.

[0101] If the reverse load rate is less than or equal to 0, the carrying capacity level of the distribution network area corresponding to the transformer equipment is determined to be Level 2, and the access of distributed power sources needs to be investigated.

[0102] As can be seen, the method for assessing the carrying capacity of a distribution network disclosed in this application assesses the carrying capacity of lines based on the preset relationship between the installed capacity of lines and power sources at different voltage levels, the node voltage constraints of the distribution network, the power flow constraints of the line branches of the distribution network, and the line capacity constraints of the distribution network, obtaining a first assessment result; assessing the carrying capacity of transformer equipment based on the output coefficient of distributed power sources, the rated capacity of transformer equipment at different voltage levels, and the total load carried by transformer equipment at different voltage levels, obtaining a second assessment result; based on the hierarchical relationship between lines and transformers, the first assessment result, and the second assessment result, correcting the carrying capacity of multi-level distributed power sources in the region, and determining a third assessment result; based on the third assessment result, determining the carrying capacity of distributed power sources in all areas of the distribution network and the assessment result of the carrying capacity level of all areas of the distribution network. It is evident that the above method not only considers modeling and calculating the carrying capacity of transformers and lines at each level, but also considers the mutual influence of carrying capacity between equipment and lines at different voltage levels, and performs data correction, thereby better determining the carrying capacity of all areas of the distribution network and improving the accuracy of the assessment results of the distribution network carrying capacity.

[0103] The following describes an apparatus for evaluating the carrying capacity of a distribution network according to an embodiment of this application. The apparatus described below can be referred to in correspondence with the method for evaluating the carrying capacity of a distribution network described above.

[0104] This application also provides a schematic diagram of the structure of a distribution network carrying capacity assessment device, as shown in the embodiment. Figure 2 As shown. The device includes a first evaluation unit 201, a second evaluation unit 202, a first determination unit 203, a second determination unit 204, and a third determination unit 205.

[0105] The first evaluation unit 201 is used to evaluate the carrying capacity of lines at different voltage levels in all areas of the distribution network according to the preset relationship between the installed capacity of lines and power sources at different voltage levels, the node voltage constraints of the distribution network, the power flow constraints of the line branches of the distribution network, and the line capacity constraints of the distribution network, so as to obtain the first evaluation result corresponding to the lines at different voltage levels in the area.

[0106] The second evaluation unit 202 is used to evaluate the carrying capacity of transformer equipment at different voltage levels based on the output coefficient of distributed power sources, the rated capacity of transformer equipment at different voltage levels, and the total load carried by transformer equipment at different voltage levels, so as to obtain the second evaluation results corresponding to transformer equipment at different voltage levels in the region.

[0107] The first determining unit 203, based on the first evaluation result and the second evaluation result, corrects the carrying capacity of the multi-level distributed power supply in the region and determines the third evaluation result.

[0108] The second determining unit 204 is used to determine the distributed power carrying capacity of all areas of the distribution network based on the third evaluation result.

[0109] The third determining unit 205 is used to determine the carrying capacity level of all areas of the distribution network based on the third evaluation result.

[0110] The line carrying capacity is evaluated based on the preset relationship between the installed capacity of lines and power sources at different voltage levels, the node voltage constraints of the distribution network, the power flow constraints of the line branches of the distribution network, and the line capacity constraints of the distribution network, resulting in a first evaluation result. The carrying capacity of transformer equipment is evaluated based on the output coefficient of distributed generation, the rated capacity of transformer equipment at different voltage levels, and the total load carried by transformer equipment at different voltage levels, resulting in a second evaluation result. Based on the hierarchical relationship between lines and transformers, the first evaluation result, and the second evaluation result, the carrying capacity of multi-level distributed generation within the region is corrected, resulting in a third evaluation result. Based on the third evaluation result, the carrying capacity of distributed generation in all areas of the distribution network and the evaluation result of the distribution network's carrying capacity are determined. It is evident that the above device not only considers modeling and calculating the carrying capacity of transformers and lines at each level, but also considers the mutual influence of carrying capacity between equipment and lines at different voltage levels and performs data correction, thereby better determining the carrying capacity of all areas of the distribution network and improving the accuracy of the distribution network carrying capacity evaluation results.

[0111] As one possible implementation, the node voltage constraint equations of the distribution network are as follows:

[0112] V i，min ≤V i，t ≤Vi，max

[0113] V i，min V is the lower voltage limit for the safe operation of node i in the distribution network, where i is any node in the distribution network. i，max V is the upper limit of voltage for safe operation of node i of the power distribution line. i，t Let represent the voltage at node i at time t, where t is any arbitrary time point.

[0114] As one possible implementation, the power flow constraint equations for the line branches of the distribution network are as follows:

[0115] V j，t =V i，t -(r ij P ij，t +x ij Q ij，t )

[0116] Among them, V j，t V represents the voltage at node j at time t. i，t P represents the voltage at node i of the power distribution line at time t. ij，t r represents the active power flowing through branch ij at time point t. ij x represents the resistance of branch ij. ij Q represents the resistance of branch ij. ij，t This represents the reactive power flowing through branch ij at time point t.

[0117] As one possible implementation, the line capacity constraint equations of the distribution network are as follows:

[0118]

[0119] Among them, P ij，t Q represents the active power flowing through branch ij at time point t. ij，t S represents the reactive power flowing through branch ij at time point t. ij This indicates the line capacity of branch ij.

[0120] As one possible implementation, the voltage level of the transformer equipment is 220kV, and the second evaluation result can be calculated according to the following formula:

[0121]

[0122] If the voltage level of the transformer equipment is other than 220kV, the second evaluation result is calculated according to the following formula.

[0123]

[0124] Among them, SDG Adding capacity to distributed power sources, whereby the added capacity represents the second evaluation result corresponding to the transformer equipment, k t S represents the output factor of distributed generation. N Rated capacity of transformer equipment λ represents the total load carried by the transformer equipment, and λ represents the reverse load rate after the distributed power source is connected.

[0125] As one possible implementation, the first determining unit specifically includes:

[0126] The first comparison unit is used to compare the second evaluation result corresponding to the transformer equipment at the first voltage level with the first evaluation result corresponding to the line below the first voltage level. If the second evaluation result corresponding to the transformer equipment at the first voltage level is larger, then the first evaluation result corresponding to the line below the first voltage level is determined as the third evaluation result corresponding to the line below the first voltage level in the multi-level distributed power supply carrying capacity. If the second evaluation result corresponding to the transformer equipment at the first voltage level is smaller, then the first evaluation result corresponding to the line below the first voltage level is adjusted, and the second evaluation result corresponding to the transformer equipment at the first voltage level is taken as the third evaluation result corresponding to the line below the first voltage level in the multi-level distributed power supply carrying capacity.

[0127] The second comparison unit is used to compare the first evaluation result corresponding to the second voltage level line with the second evaluation result corresponding to the transformer equipment of the second voltage level. If the first evaluation result corresponding to the second voltage level line is larger, the first evaluation result corresponding to the transformer of the second voltage level is determined as the third evaluation result corresponding to the transformer of the second voltage level in the multi-level distributed power carrying capacity. If the first evaluation result corresponding to the second voltage level line is smaller, the second evaluation result corresponding to the transformer equipment of the second voltage level is adjusted, and the first evaluation result corresponding to the second voltage level line is used as the second evaluation result corresponding to the transformer equipment of the second voltage level in the multi-level distributed power carrying capacity.

[0128] As one possible implementation, the third determining unit is specifically used for:

[0129] Calculate the reverse load rate based on the third evaluation result;

[0130] Based on the reverse load rate, determine the carrying capacity level of all areas of the distribution network.

[0131] This application also provides a device that may include a memory and a processor. The memory stores a computer program, and when the processor calls the computer program in the memory, it can implement the steps provided in the above embodiments. Of course, the device may also include various network interfaces, power supplies, and other components.

[0132] It should be noted that the device provided in this application has the technical effects of any of the above embodiments, and the embodiments of this application will not be described in detail here.

[0133] This application also provides a computer-readable storage medium having a computer program stored thereon, which, when executed, can perform the steps provided in the above embodiments. The storage medium may include various media capable of storing program code, such as a USB flash drive, a portable hard drive, a read-only memory (ROM), a random access memory (RAM), a magnetic disk, or an optical disk.

[0134] It should be noted that the computer-readable storage medium provided in this application has the technical effects of any of the above embodiments, and the embodiments of this application will not be described in detail here.

[0135] It should be understood that in this application, "at least one (item)" means one or more, and "more than" means two or more. "And / or" is used to describe the relationship between related objects, indicating that three relationships can exist. For example, "A and / or B" can represent three cases: only A exists, only B exists, and both A and B exist simultaneously, where A and B can be singular or plural. The character " / " generally indicates that the preceding and following related objects are in an "or" relationship. "At least one (item) of the following" or similar expressions refer to any combination of these items, including any combination of single or plural items. For example, at least one (item) of a, b, or c can represent: a, b, c, "a and b", "a and c", "b and c", or "a and b and c", where a, b, and c can be single or multiple.

[0136] It should also be noted that, in this document, relational terms such as "first" and "second" are used only to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitations, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element.

[0137] This document uses specific examples to illustrate the principles and implementation methods of this application. The descriptions of the embodiments above are only for the purpose of helping to understand the method and core ideas of this application. It should be noted that those skilled in the art can make several improvements and modifications to this application without departing from the principles of this application, and these improvements and modifications also fall within the protection scope of the claims of this application.

Claims

1. A method for evaluating the carrying capacity of a power distribution network, characterized in that, The method includes: Based on the preset relationship between the installed capacity of lines and power sources at different voltage levels, the node voltage constraints of the distribution network, the power flow constraints of the line branches of the distribution network, and the line capacity constraints of the distribution network, the carrying capacity of lines at different voltage levels in all areas of the distribution network is evaluated to obtain the first evaluation result corresponding to the lines at different voltage levels in the area. The carrying capacity of transformer equipment at different voltage levels is evaluated based on the output coefficient of distributed power sources, the rated capacity of transformer equipment at different voltage levels, and the total load carried by transformer equipment at different voltage levels, so as to obtain the second evaluation results corresponding to transformer equipment at different voltage levels in the region. Based on the hierarchical relationship between lines and transformers, the first evaluation result, and the second evaluation result, the carrying capacity of multi-level distributed power sources in the region is corrected, and a third evaluation result is determined, including: comparing the second evaluation result corresponding to the transformer equipment at the first voltage level with the first evaluation result corresponding to the line below the first voltage level; if the second evaluation result corresponding to the transformer equipment at the first voltage level is larger, then the first evaluation result corresponding to the line below the first voltage level is determined as the third evaluation result corresponding to the line below the first voltage level in the carrying capacity of multi-level distributed power sources. If the second evaluation result corresponding to the transformer equipment at the first voltage level is small, then the first evaluation result corresponding to the line at a voltage level lower than the first voltage level is adjusted, and the second evaluation result corresponding to the transformer equipment at the first voltage level is used as the third evaluation result corresponding to the line at a voltage level lower than the first voltage level in the multi-level distributed power carrying capacity. Compare the first evaluation results corresponding to the second voltage level line with the second evaluation results corresponding to the transformer equipment of the second voltage level; If the first evaluation result corresponding to the second voltage level line is large, then the first evaluation result corresponding to the second voltage level transformer is determined to be the third evaluation result corresponding to the second voltage level transformer in the multi-level distributed power carrying capacity. If the first evaluation result corresponding to the second voltage level line is small, then the second evaluation result corresponding to the transformer equipment of the second voltage level is adjusted, and the first evaluation result corresponding to the second voltage level line is used as the second evaluation result corresponding to the transformer equipment of the second voltage level in the multi-level distributed power carrying capacity. Based on the results of the third assessment, the distributed power carrying capacity of all areas of the distribution network is determined; Based on the results of the third assessment, the carrying capacity level of all areas of the distribution network is determined.

2. The method according to claim 1, characterized in that, The node voltage constraint equations for the distribution network are as follows: This is the lower voltage limit for the safe operation of node i in the distribution network, where i is any node in the distribution network. The upper limit of voltage for safe operation of distribution line node i. Let represent the voltage at node i at time t, where t is any arbitrary time point.

3. The method according to claim 1, characterized in that, The power flow constraint equations for the line branches of the distribution network are as follows: in, This represents the voltage at node j at time t. This represents the voltage at node i of the power distribution line at time t. This represents the active power flowing through branch ij at time point t. This represents the resistance of branch ij. This represents the resistance of branch ij. This represents the reactive power flowing through branch ij at time point t.

4. The method according to claim 1, characterized in that, The line capacity constraint equations for the distribution network are as follows: in, This represents the active power flowing through branch ij at time point t. Let represent the reactive power flowing through branch ij at time point t. This indicates the line capacity of branch ij.

5. The method according to claim 1, characterized in that, The voltage level of the transformer equipment is 220kV, and the second evaluation result can be calculated according to the following formula: λ= 0; If the voltage level of the transformer equipment is other than 220kV, the second evaluation result can be calculated according to the following formula. λ= ; in, The newly added capacity for distributed power sources is used to represent the second evaluation result corresponding to the transformer equipment. Indicates the output coefficient of distributed power sources. Rated capacity of transformer equipment λ represents the total load carried by the transformer equipment, and λ represents the reverse load rate after the distributed power source is connected.

6. The method according to claim 1, characterized in that, The determination of the carrying capacity level of all areas of the distribution network based on the third assessment result includes: Calculate the reverse load rate based on the third evaluation result; Based on the reverse load rate, determine the carrying capacity level of all areas of the distribution network.

7. A device for evaluating the carrying capacity of a power distribution network, characterized in that, The device includes: The first evaluation unit is used to evaluate the line carrying capacity of different voltage levels in all areas of the distribution network according to the preset relationship between the line and the power supply installed capacity of different voltage levels, the node voltage constraints of the distribution network, the line branch power flow constraints of the distribution network, and the line capacity constraints of the distribution network, so as to obtain the first evaluation result corresponding to the line of different voltage levels in the area. The second evaluation unit is used to evaluate the carrying capacity of transformer equipment at different voltage levels based on the output coefficient of distributed power sources, the rated capacity of transformer equipment at different voltage levels, and the total load carried by transformer equipment at different voltage levels, so as to obtain the second evaluation results corresponding to transformer equipment at different voltage levels in the region. The first determining unit, based on the first evaluation result and the second evaluation result, corrects the multi-level distributed power carrying capacity in the region and determines the third evaluation result; The second determining unit is used to determine the distributed power carrying capacity of all areas of the distribution network based on the third evaluation result. The third determining unit is used to determine the carrying capacity level of the distribution network based on the third evaluation result; the first determining unit specifically includes: The first comparison unit is used to compare the second evaluation result corresponding to the transformer equipment at the first voltage level with the first evaluation result corresponding to the line below the first voltage level. If the second evaluation result corresponding to the transformer equipment at the first voltage level is larger, then the first evaluation result corresponding to the line below the first voltage level is determined as the third evaluation result corresponding to the line below the first voltage level in the multi-level distributed power supply carrying capacity. If the second evaluation result corresponding to the transformer equipment at the first voltage level is smaller, then the first evaluation result corresponding to the line below the first voltage level is adjusted, and the second evaluation result corresponding to the transformer equipment at the first voltage level is taken as the third evaluation result corresponding to the line below the first voltage level in the multi-level distributed power supply carrying capacity. The second comparison unit is used to compare the first evaluation result corresponding to the second voltage level line with the second evaluation result corresponding to the transformer equipment of the second voltage level. If the first evaluation result corresponding to the second voltage level line is larger, the first evaluation result corresponding to the transformer of the second voltage level is determined as the third evaluation result corresponding to the transformer of the second voltage level in the multi-level distributed power carrying capacity. If the first evaluation result corresponding to the second voltage level line is smaller, the second evaluation result corresponding to the transformer equipment of the second voltage level is adjusted, and the first evaluation result corresponding to the second voltage level line is used as the second evaluation result corresponding to the transformer equipment of the second voltage level in the multi-level distributed power carrying capacity.

8. A device for assessing the carrying capacity of a power distribution network, characterized in that, include: Memory, used to store computer programs; A processor for executing a computer program stored in the memory to implement the steps of the method as claimed in any one of claims 1 to 6.

9. A computer-readable storage medium storing a computer program thereon, characterized in that, The computer program is executed by a processor to implement the steps of the method as claimed in any one of claims 1 to 6.

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