A method and system for measuring the accommodation capacity of new energy in a power distribution network

Abstract

This invention relates to the field of renewable energy absorption capacity calculation technology for distribution networks, and discloses a method and system for calculating the renewable energy absorption capacity of distribution networks. The method includes obtaining the active power forecast value, reactive power setpoint value, and generation limit upper limit of each renewable energy power station, as well as the active power load value and reactive power load value of each node in the distribution network, the network parameters, and operating limits of the distribution network; calculating the node injection power; obtaining the power flow state, over-limit objects, and over-limit quantities based on the node injection power and network parameters; progressively reducing the active power component in the node injection power of each renewable energy power station access node to obtain the over-limit change amount; determining the degree of over-limit impact based on the over-limit change amount and constructing an over-limit impact matrix; obtaining an initial generation limit scheme based on the over-limit impact matrix, over-limit quantity, and generation limit upper limit; and obtaining the power absorption capacity of the power station and the renewable energy absorption capacity of the distribution network based on the initial generation limit scheme. This method realizes the calculation of renewable energy absorption capacity of distribution networks.

Description

Technical Field

[0001] This invention relates to the field of new energy absorption capacity calculation technology for distribution networks, and in particular to a method and system for calculating the new energy absorption capacity of distribution networks. Background Technology

[0002] Currently, with the increasing number of renewable energy power plants connected to distribution lines, a single feeder may simultaneously receive power injection from multiple renewable energy power plants during certain operating periods. The line current-carrying state and node voltage are affected by the combined influence of the power plant connection location, power plant output, and node load changes. To determine the acceptable power of each renewable energy power plant within the operating limits of the distribution line, power flow analysis is typically required based on the predicted power output of the power plant, node load, line parameters, and operating limits.

[0003] In one existing technology, line power flow is first calculated based on the predicted output and node load of each renewable energy power station. Upon detecting line overload or node voltage exceeding limits, power limiting is then allocated according to the installed capacity of each renewable energy power station, the predicted output ratio, or a uniform reduction ratio. Because the access nodes of different renewable energy power stations and their electrical connections with the exceeding lines and nodes differ, allocating power limiting according to a fixed ratio can easily lead to a mismatch between the power limiting borne by each renewable energy power station and the power regulation required to eliminate the corresponding exceeding condition, thus necessitating repeated adjustments to the power limiting results.

[0004] Existing technologies present a problem where it is difficult to accurately allocate the power generation capacity when multiple power plants jointly cause the grid to exceed its operating limits. Summary of the Invention

[0005] This invention provides a method and system for calculating the renewable energy absorption capacity of a distribution network, in order to solve the problem in the prior art where it is difficult to accurately allocate the power generation capacity when multiple power plants jointly cause the grid to exceed the operating limit.

[0006] Firstly, in order to solve the above-mentioned technical problems, the present invention provides a method for calculating the renewable energy absorption capacity of a distribution network, comprising: Obtain the active power prediction value, reactive power setpoint value, and power generation limit of each new energy power station, as well as the active power load value and reactive power load value of each node in the distribution network, the network parameters and operating limits of the distribution network, and calculate the node injection power based on the active power prediction value, the reactive power setpoint value, the active power load value and the reactive power load value; Power flow calculation is performed based on the node injection power and the network parameters to obtain the power flow state. The power flow state is then compared with the operating limits to obtain the objects and quantities that exceed the limits. The active component in the node injection power of each new energy power station access node is reduced one by one and power flow calculation is performed to obtain the over-limit change amount. The degree of over-limit impact is determined based on the over-limit change amount and an over-limit impact matrix is ​​constructed. Based on the over-limit impact matrix, the over-limit amount, and the upper limit of the power restriction, the power restriction power of each new energy power station is allocated according to the condition of eliminating the over-limit amount and minimizing the total power restriction power, so as to obtain the initial power restriction scheme; The candidate absorption power is calculated based on the initial power restriction scheme. The power flow is then checked against the candidate absorption power to obtain the power absorption power of the power plants. The renewable energy absorption capacity of the distribution network is then calculated based on the power absorption power of the power plants.

[0007] Secondly, the present invention provides a new energy absorption capacity calculation system for a power distribution network, comprising: a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor executes the program to implement the method described above.

[0008] Compared with the prior art, the present invention has the following beneficial effects: (1) This invention determines the degree of influence of each new energy power station on different over-limit objects by reducing the active power injection of each new energy power station access node one by one and calculating the changes in the over-limit amount of the distribution network before and after the reduction, and then constructs an over-limit influence matrix. In this way, the correspondence between the power regulation amount of new energy power stations and line overload and node overvoltage is established, so that the allocation of limited power can reflect the actual impact of different access locations on the over-limit state and improve the accuracy of the power limited allocation of multiple power stations.

[0009] (2) This invention uses the over-limit impact matrix, the over-limit amount, and the upper limit of the power generation restriction for each new energy power station as the conditions for allocating the power generation restriction, and determines the power generation restriction scheme for stations with smaller total power generation restriction under the premise of eliminating the over-limit amount in the distribution network. This scheme can configure the power generation restriction according to the difference in the impact of each new energy power station on the over-limit object, reduce the ineffective power generation restriction caused by fixed ratio allocation, and improve the absorbability of the predicted output of new energy within the operating limits of the distribution network.

[0010] (3) This invention calculates candidate absorption power based on the power plant power limiting scheme, verifies the power flow state corresponding to the candidate absorption power, determines the power plant absorption power after meeting the line current carrying limit and node voltage limit, and then statistically analyzes the power plant absorption power for each evaluation period. This ensures that the calculation results simultaneously meet the physical operation constraints and temporal operation conditions of the distribution network, improving the reliability of the calculation results of the new energy absorption capacity of the distribution network. Attached Figure Description

[0011] Figure 1 This is a schematic diagram of the calculation method for the renewable energy absorption capacity of the distribution network provided in the first embodiment of the present invention. Detailed Implementation

[0012] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0013] Reference Figure 1 The first embodiment of the present invention provides a method for calculating the renewable energy absorption capacity of a distribution network, including the following steps: S1, obtain the active power prediction value, reactive power set value and power generation limit of each new energy power station, as well as the active power load value and reactive power load value of each node of the distribution network, the network parameters and operating limits of the distribution network, and calculate the node injection power based on the active power prediction value, the reactive power set value, the active power load value and the reactive power load value; S2, perform power flow calculation based on the node injection power and the network parameters to obtain the power flow state, and compare the power flow state with the operating limit to obtain the over-limit objects and over-limit quantities; S3, reduce the active component in the node injection power of each new energy power station access node one by one and perform power flow calculation to obtain the over-limit change amount, determine the over-limit impact degree based on the over-limit change amount and construct the over-limit impact matrix; S4. Based on the over-limit impact matrix, the over-limit amount, and the upper limit of the power restriction, allocate the power restriction power of each new energy power station according to the condition of eliminating the over-limit amount and minimizing the total power restriction power, and obtain the initial power restriction scheme. S5. Calculate candidate absorption power based on the initial power restriction scheme, perform power flow verification on the candidate absorption power to obtain the power absorption power of the power station, and calculate the renewable energy absorption capacity of the distribution network based on the power absorption power of the power station.

[0014] In step S1, the active power prediction value, reactive power setting value, and power generation limit of each new energy power station are obtained, as well as the active power load value and reactive power load value of each node of the distribution network, the network parameters and operating limits of the distribution network, and the node injection power is calculated based on the active power prediction value, the reactive power setting value, the active power load value and the reactive power load value.

[0015] This includes acquiring the active power forecast, reactive power setpoint, and power generation limit of each renewable energy power station, as well as the active and reactive power load values ​​of each node in the distribution network, and the network parameters and operating limits of the distribution network, including: Obtain the active power prediction value, reactive power setting value, power generation limit and assessment period duration corresponding to each assessment period within the assessment cycle, as well as the active power load value and reactive power load value corresponding to each node of the distribution network; Obtain the access node of the power station, and perform time alignment of the active power prediction value, the reactive power set value, the active power load value and the reactive power load value according to the evaluation period within the evaluation cycle, and establish the correspondence between each new energy power station and each node of the distribution network based on the access node of the power station; Obtain the topology, line impedance, and reference voltage; associate the line impedance with the corresponding line based on the topology, and associate the reference voltage with the power node to obtain the network parameters; Obtain the line current carrying limit and the node voltage limit. Associate the line current carrying limit and the node voltage limit with the corresponding line and node respectively according to the line identifier and the node identifier to obtain the operating limit.

[0016] In one implementation, the active power prediction record output by the prediction terminal of the new energy power station is read through the data interface of the new energy power station, and the reactive power setting record and active power adjustment record are read through the control terminal of the new energy power station.

[0017] The active power prediction record includes a station identifier, a time identifier, and an active power prediction value; the reactive power setting record includes a station identifier, a time identifier, and a reactive power setting value; the active power adjustment record includes a station identifier, a time identifier, a unit active power prediction value for each power generation unit, a minimum active power operating value, and an active power data resolution.

[0018] In this embodiment, the predicted active power value is determined as the predicted active power value of the corresponding new energy power station, and the set reactive power value is determined as the set reactive power value of the corresponding new energy power station.

[0019] For each power generation unit in operation, the difference between the predicted active power value and the minimum active power operating value of the unit is calculated. When the difference is not less than zero, the difference is retained; when the difference is less than zero, the difference is set to zero. The differences corresponding to each power generation unit within the same renewable energy power station are summed, and the smaller value between the summation result and the predicted active power value of the corresponding renewable energy power station is taken to obtain the upper limit of power generation limitation.

[0020] It should be noted that the minimum active power operating value is read by the new energy power station control terminal based on the operating status of the power generation unit within the corresponding assessment period. When the power generation unit is in operation, the corresponding unit active power prediction value and the minimum active power operating value are read; when the power generation unit is not in operation, the corresponding unit active power prediction value and the minimum active power operating value are both recorded as zero.

[0021] The active power data resolution refers to the minimum power interval that the active power fields in the active power prediction record and the active power adjustment record can represent. In this embodiment, the corresponding minimum power interval is determined according to the number of decimal places retained for each active power field, and the maximum value among the minimum power intervals is taken as the active power data resolution of the corresponding renewable energy power station.

[0022] It should be noted that the active power data resolution is used to determine the initial disturbance step size of the power flow disturbance and to judge whether the over-limit change has reached the recordable range, and is not used as a discrete constraint on the power limit in the linear programming model.

[0023] This embodiment reads the node load records output by the node load forecasting terminal through the distribution network operation data interface. The node load record includes a node identifier, a time identifier, an active load value, and a reactive load value. The active load value is determined as the active load value of the corresponding node, and the reactive load value is determined as the reactive load value of the corresponding node.

[0024] In one implementation, the start and end times of the evaluation period are read through a measurement request interface. This embodiment determines the time intervals between adjacent time markers in the active power prediction record, the reactive power setting record, the active power adjustment record, and the node load record, converts each time interval into seconds, and determines the greatest common divisor of each time interval as the duration of the evaluation period.

[0025] For data records with time intervals longer than the evaluation period, the values ​​in the data records are associated with each evaluation period covered by the effective period of the data record. Except for the last data record, the effective period is the time range from the current time marker to the next time marker; the effective period for the last data record is the time range from the corresponding time marker to the end time of the evaluation period.

[0026] In this embodiment, an evaluation period sequence is established based on the start time, end time of the evaluation period and the duration of the evaluation period, and each data record is associated with the corresponding evaluation period according to the time identifier.

[0027] Time alignment is completed when each assessment period has a corresponding active power prediction value, reactive power setting value, power generation limit, active power load value, and reactive power load value.

[0028] If any of the predicted active power value, the set reactive power value, the upper limit for power generation, the active power load value, or the reactive power load value is missing in any assessment period, the corresponding terminal will be re-requested to send the corresponding data record. If the data is complete after the re-request, time alignment will be completed; if the data is still incomplete after the re-request, an incomplete data status will be output and the calculation for the current assessment period will be terminated.

[0029] In one implementation, the power distribution network parameter interface is used to read the station access relationship record, line connection record, line parameter record, line switch status record, node parameter record, and power equipment record.

[0030] The site access relationship record includes site identifier and node identifier; the line connection record includes line identifier, first node identifier and last node identifier; the line parameter record includes line identifier, line resistance, line reactance and line current carrying limit; the line switch status record includes line identifier and line switch status; the node parameter record includes node identifier, node type and node voltage limit; the power supply equipment record includes reference voltage and rated capacity.

[0031] In this embodiment, each new energy power station is associated with its corresponding power station access node based on the power station identifier and the node identifier. When multiple new energy power stations are connected to the same node, each new energy power station retains its own power station identifier and is associated with the same node identifier.

[0032] In this embodiment, the lines whose switch state is "on" are retained. The topology relationship is formed according to the first and last node identifiers of the lines, and each line and node is traversed starting from the node whose node type is a power node.

[0033] The topology is defined as a radial topology when it includes a power node, all non-power nodes can be connected to the power node, and each non-power node has only one upstream path.

[0034] When the number of power nodes is not one, no node can be connected to the power node, or any non-power node has more than two upstream paths, the topology data abnormality status is output and the calculation of the current evaluation cycle is terminated.

[0035] In this embodiment, the line resistance and line reactance corresponding to the same line identifier are combined into the line impedance, and the line impedance is associated with the corresponding line; the reference voltage is associated with the power node; the line current carrying limit is associated with the corresponding line; and the node voltage limit is associated with the corresponding node.

[0036] It should be noted that this embodiment uses per-unit values ​​for power flow calculation. The reference voltage is determined as the base voltage, and the rated capacity is determined as the base capacity; the square of the base voltage is divided by the base capacity to obtain the base impedance; the base capacity is divided by the product of the square root of three and the base voltage to obtain the base current.

[0037] When performing power flow calculations, the active power injection and reactive power injection at each node are divided by the reference capacity, the line impedance is divided by the reference impedance, the line current carrying limit is divided by the reference current, and the node voltage limit is divided by the reference voltage. The disturbance step size and the power limiting are calculated using actual power quantities.

[0038] The calculation of node injection power based on the active power prediction value, the reactive power setpoint, the active power load value, and the reactive power load value includes: Based on the power station access node, the active power predicted values ​​corresponding to the new energy power stations connected to the same node are summed to obtain the active power output of the node. Based on the power station access node, the reactive power setpoints corresponding to the new energy power stations connected to the same node are summed to obtain the node reactive power output; Set the active power output and reactive power output of the nodes that are not connected to the new energy power station to zero. The difference between the active power output of the node and the active load value of the corresponding node is calculated to obtain the active power injection of the node; the difference between the reactive power output of the node and the reactive load value of the corresponding node is calculated to obtain the reactive power injection of the node. The active power injection and reactive power injection of the node are combined to form the node injection power.

[0039] In one implementation, each node in the distribution network is processed sequentially according to its node identifier. For the current node, the active power predicted values ​​corresponding to each renewable energy power station connected to the node are summed to obtain the active power output of the node; the reactive power setpoint values ​​corresponding to each renewable energy power station are summed after retaining their positive and negative signs to obtain the reactive power output of the node.

[0040] This embodiment adopts a sign rule where power injection is positive and power consumption is negative. When the reactive power setpoint is positive, it indicates that the corresponding renewable energy power station injects reactive power into the node; when the reactive power setpoint is negative, it indicates that the corresponding renewable energy power station absorbs reactive power from the node.

[0041] When a node is connected to a renewable energy power station, the active power output and reactive power output of the node are calculated based on the renewable energy power station connected to the node; when a node is not connected to a renewable energy power station, the active power output and reactive power output of the node are set to zero.

[0042] For each node, the active power injection amount is obtained by subtracting the corresponding active power load value from the active power output of the node; the reactive power injection amount is obtained by subtracting the corresponding reactive power load value from the reactive power output of the node.

[0043] In step S2, power flow calculation is performed based on the node injection power and the network parameters to obtain the power flow state. The power flow state is then compared with the operating limits to obtain the objects and quantities that exceed the limits.

[0044] The power flow state is obtained by calculating the power flow based on the node injection power and the network parameters, including: The initial node voltage is set according to the reference voltage, and the node current is calculated based on the node injected power and the initial node voltage. According to the topological relationship, the node currents are aggregated from the end node to the power node to obtain the branch current; Based on the branch current and the line impedance, the node voltage is updated from the power supply node to the terminal node; Repeatedly calculate the node current, the branch current, and the node voltage until the maximum difference between the corresponding node voltages in two adjacent calculations is not greater than a preset convergence threshold, thereby obtaining the power flow state including the branch current and the node voltage.

[0045] In one implementation, a single-phase positive-sequence equivalent network is used to represent the radial topology, and a forward-backward substitution method is used for power flow calculation. Based on the identifiers of the first and last nodes of each line, the upstream and downstream relationships of each node are determined, and nodes not connected to downstream lines are identified as last nodes.

[0046] In this embodiment, the initial node voltage of the power supply node is set to the per-unit value corresponding to the reference voltage, and the node voltage of the power supply node is kept unchanged; the initial node voltage of the other nodes is set to a complex voltage with an amplitude of 1 per-unit value and a phase angle of zero.

[0047] It should be noted that when calculating the node current, the sign of the injected power at the node is changed to obtain the complex power obtained by the corresponding node from the upstream line; the complex power is divided by the current node voltage of the corresponding node, and the conjugate of the division result is taken to obtain the node current.

[0048] In this embodiment, the node current of each node and the branch current of the downstream line are summed in complex order from the end node to the power node to obtain the branch current of each line.

[0049] After summarizing the branch currents, the branch currents of each line are multiplied by the corresponding line impedances in the order from the power source node to the end node to obtain the line voltage drop. The line voltage drop is then subtracted from the node voltage of the first end node to obtain the updated node voltage of the end node.

[0050] In this embodiment, a single branch current summary and a single node voltage update are recorded as one iteration. After each iteration, the complex difference between the current node voltage and the previous node voltage of each non-power node is calculated, and the maximum value among the amplitudes of the complex differences is determined as the maximum node voltage difference.

[0051] It should be noted that in this embodiment, the preset convergence threshold is determined based on the numerical resolution of the node voltage result field. The number of decimal places retained in the node voltage result field is read, and the minimum voltage interval that can be recorded is determined based on the number of decimal places. One-hundredth of the minimum voltage interval is then determined as the preset convergence threshold.

[0052] For example, when the node voltage result field is retained to four decimal places, the minimum voltage interval is 0.0001 per unit value. One-hundredth of the 0.0001 per unit value is determined as the preset convergence threshold, resulting in a 0.000001 per unit value.

[0053] Before performing the formal calculation, this embodiment uses the node injection power corresponding to each evaluation period with complete data within the evaluation cycle to conduct a power flow convergence test, and records the number of iterations required for each evaluation period to reach the preset convergence threshold. When the evaluation cycle includes 96 evaluation periods, the maximum number of iterations obtained by the power flow convergence test is 8. In this embodiment, an integer greater than 12 times the maximum number of iterations, 100, is determined as the maximum number of iterations for power flow calculation, so that the maximum number of iterations covers the difference in the number of iterations caused by changes in node injection power in each evaluation period.

[0054] When the maximum difference in node voltage is not greater than the preset convergence threshold, the iteration stops, and the current branch current and node voltage are determined as the power flow state.

[0055] When the maximum difference in node voltage is greater than the preset convergence threshold and the number of iterations has not reached 100, the iteration continues.

[0056] When the number of iterations reaches 100 and the maximum difference in node voltage is still greater than the preset convergence threshold, the power flow calculation non-convergence state is output and the calculation of the current evaluation cycle is terminated.

[0057] Specifically, comparing the power flow state with the operating limits to obtain the objects and quantities of exceeding the limits includes: The amplitude of the branch current is compared with the current carrying limit of the corresponding line. Lines whose branch current amplitude is greater than the current carrying limit are identified as line over-limit objects. The difference between the amplitude of the branch current and the current carrying limit is calculated to obtain the line over-limit amount. The amplitude of the node voltage is compared with the upper limit of the node voltage of the corresponding node. Nodes whose amplitude of the node voltage is greater than the upper limit of the node voltage are identified as voltage over-limit objects. The difference between the amplitude of the node voltage and the upper limit of the node voltage is calculated to obtain the voltage over-limit amount. The line over-limit object and the voltage over-limit object are identified as the over-limit object, and the line over-limit amount and the voltage over-limit amount are identified as the over-limit amount.

[0058] In one implementation, the per-unit branch current corresponding to each line is extracted, the complex amplitude of the per-unit branch current is calculated, and the complex amplitude is multiplied by the reference current to obtain the amplitude of the branch current recorded in amperes.

[0059] When the amplitude of the branch current is greater than the corresponding line current carrying limit, the corresponding line is identified as the line over-limit object, and the line over-limit amount is calculated; when the amplitude of the branch current is not greater than the corresponding line current carrying limit, the corresponding line over-limit amount is recorded as zero.

[0060] When the amplitude of the node voltage is greater than the corresponding upper limit of the node voltage, the corresponding node is identified as the voltage over-limit object, and the voltage over-limit amount is calculated; when the amplitude of the node voltage is not greater than the corresponding upper limit of the node voltage, the corresponding voltage over-limit amount is recorded as zero.

[0061] It should be noted that the line over-limit is recorded in amperes, and the voltage over-limit is recorded in per-unit values. The line over-limit objects, the voltage over-limit objects, and their corresponding over-limit quantities are arranged according to the line identifier and node identifier.

[0062] When the line over-limit object or the voltage over-limit object exists, a non-empty over-limit object and the corresponding over-limit quantity are obtained; when the line over-limit object and the voltage over-limit object do not exist, the over-limit object is recorded as an empty set and the over-limit quantity is recorded as a zero value.

[0063] In step S3, the active power component in the node injection power of each new energy power station access node is reduced one by one and power flow calculation is performed to obtain the over-limit change amount. The degree of over-limit impact is determined based on the over-limit change amount and an over-limit impact matrix is ​​constructed.

[0064] Specifically, the active power component in the node injection power of each renewable energy power station access node is reduced one by one, and power flow calculation is performed to obtain the over-limit change amount, including: Each new energy power station is sequentially identified as a target power station, and a disturbance step size is determined that is greater than zero and not greater than the smaller value between the upper limit of power generation restriction and the active power prediction value corresponding to the target power station. The disturbance step size is subtracted from the active power injection of the target power station access node, while keeping the active power injection of the remaining nodes unchanged, to obtain the disturbance active power injection. The disturbance active power injection and the node reactive power injection are combined to form the disturbance injection power; Power flow calculation is performed based on the disturbance injection power and the network parameters to obtain the disturbance power flow state. The disturbance power flow state is then compared with the operating limit to obtain the disturbance limit violation amount corresponding to the violation object. The difference between the over-limit amount and the disturbance over-limit amount is calculated to obtain the over-limit change amount.

[0065] In one implementation, active power perturbation of renewable energy power plants is performed for each evaluation period. Each renewable energy power plant is sequentially identified as a target power plant according to its identifier, and the active power of one target power plant is changed each time. After the perturbation calculation for the current target power plant is completed, the node injection power obtained in step S2 is restored, and then the next renewable energy power plant is processed.

[0066] In this embodiment, the smaller of the upper limit of power generation and the predicted active power value corresponding to the target power station is determined as the perturbed power.

[0067] When the perturbable power is zero, the degree of influence of the target station on each of the over-limit objects is recorded as zero.

[0068] When the perturbable power is zero, the degree of the impact of the target power station on each of the over-limit objects is recorded as zero, and the next new energy power station is processed.

[0069] When the perturbed power is greater than zero, the active power data resolution corresponding to the target power station is compared with the perturbed power, and the smaller of the two values ​​is determined as the current perturbation step size.

[0070] For the current disturbance step size, the current disturbance step size is subtracted from the active power injection of the target power station access node, while keeping the active power injection of the remaining nodes and the reactive power injection of all nodes unchanged, to obtain the disturbance active power injection and the disturbance injection power; power flow calculation is performed based on the disturbance injection power and the network parameters to obtain the corresponding disturbance exceedance amount and exceedance change amount.

[0071] It should be noted that when the absolute value of the over-limit change corresponding to the line over-limit object is less than the recording accuracy of the branch current, the corresponding over-limit change is set to zero; when the absolute value of the over-limit change corresponding to the voltage over-limit object is less than the recording accuracy of the node voltage, the corresponding over-limit change is set to zero.

[0072] When at least one of the aforementioned limit-crossing changes is not zero, the current disturbance step size is determined as the disturbance step size corresponding to the target station, and the disturbance limit-crossing amount is determined based on the current power flow calculation result.

[0073] When all the aforementioned out-of-limit changes are zero, and the current disturbance step size is less than the perturbed power, the current disturbance step size is increased by one active power data resolution, and the smaller value between the increase result and the perturbed power is taken as the updated current disturbance step size, and the power flow calculation is performed again.

[0074] When all the above-limit changes are zero, and the current disturbance step size is equal to the perturbed power, the degree of the above-limit impact of the target power station on each above-limit object is recorded as zero, and the next new energy power station is processed.

[0075] After the disturbance calculation for the current target power station is completed, the node injection power obtained in step S2 is restored, and then the next new energy power station is processed.

[0076] When multiple new energy power stations are connected to the same node, only the disturbance step size corresponding to the current target power station is deducted, while the active power prediction value corresponding to other new energy power stations within the same node remains unchanged.

[0077] The disturbance power flow state is obtained according to the disturbance injection power and the network parameters, following the power flow calculation method in step S2.

[0078] For each of the objects exceeding the limit determined in step S2, if the line or node still exceeds the limit after the disturbance, the corresponding disturbance exceeding the limit amount is obtained according to the exceeding limit amount calculation method in step S2; if the line or node no longer exceeds the limit after the disturbance, the corresponding disturbance exceeding the limit amount is recorded as zero.

[0079] The difference between the excess amount before the disturbance and the excess amount after the disturbance is calculated to obtain the excess change amount. When the excess change amount is positive, the corresponding excess amount decreases; when the excess change amount is zero, the corresponding excess amount does not undergo a recordable change; when the excess change amount is negative, the corresponding excess amount increases.

[0080] The process of determining the degree of impact of exceeding the limit based on the amount of change exceeding the limit and constructing the impact matrix of exceeding the limit includes: Calculate the ratio between the excess change amount and the disturbance step size corresponding to each of the target stations to obtain the degree of excess influence of each of the target stations on each of the excess objects; The degree of impact of exceeding the limit is arranged according to the arrangement that each of the aforementioned objects exceeds the limit corresponds to a row and each of the aforementioned new energy power stations corresponds to a column, so as to obtain the limit exceeding impact matrix.

[0081] In one implementation, the degree of impact of exceeding the limit is calculated according to the following formula: in, This indicates the degree of impact of the i-th renewable energy power station on the k-th over-limit object. This represents the amount of over-limit change corresponding to the k-th over-limit object for the i-th renewable energy power station. This represents the disturbance step size corresponding to the i-th new energy power station.

[0082] For line-related violations, the dimension of the impact is amperes per megawatt; for voltage-related violations, the dimension of the impact is per per-unit value per megawatt. The impact level is expressed with a positive or negative sign.

[0083] In this embodiment, the rows of the over-limit impact matrix are set according to the recording order of the over-limit objects, and the columns of the over-limit impact matrix are set according to the station identification order.

[0084] When the over-limit object is an empty set, the over-limit impact matrix is ​​set to an empty matrix and no active power disturbance is performed; when the over-limit object is not empty, the over-limit impact degree corresponding to each new energy power station is calculated in turn to obtain the over-limit impact matrix.

[0085] For example, the objects exceeding the limits include line L2 and node N3. The active power data resolution corresponding to renewable energy power station A is 0.02 MW. The smaller of the upper limit of power generation and the predicted active power value is greater than 0.02 MW, therefore 0.02 MW is determined as the disturbance step size corresponding to renewable energy power station A. Before the disturbance, the exceeding amounts of line L2 and node N3 are 12.57 amperes and 0.00258 per unit, respectively; after the disturbance, the corresponding exceeding amounts of disturbance are 11.98 amperes and 0.00233 per unit, respectively. The calculated impact of renewable energy power station A on the exceeding amounts of line L2 and node N3 is 29.50 amperes per MW and 0.01250 per unit per MW, respectively.

[0086] In step S4, based on the over-limit impact matrix, the over-limit amount, and the upper limit of the power restriction, the power restriction power of each new energy power station is allocated according to the condition of eliminating the over-limit amount and minimizing the total power restriction power, thus obtaining the initial power restriction scheme.

[0087] The initial power restriction scheme is obtained by allocating the power restriction capacity of each renewable energy power station according to the condition of eliminating the over-limit and minimizing the total restricted power, including: The power limitation power of each new energy power station is set as a decision variable, and the power limitation power of each new energy power station is summed to obtain the total power limitation power. Based on the aforementioned over-limit impact matrix and the restricted power generation of each new energy power station, calculate the over-limit reduction amount corresponding to each over-limit object; The power generation limit of each new energy power station is limited to be no less than zero, no greater than the corresponding power generation limit, and no greater than the corresponding active power prediction value, and the over-limit reduction amount is limited to be no less than the corresponding over-limit amount; A linear programming model is established with the goal of minimizing the total power limit and with constraints on the power limit and the amount of power reduction exceeding the limit. Solve the linear programming model to obtain the power limiting power of each new energy power station, and combine the power limiting power of each new energy power station into the initial power limiting scheme.

[0088] In one implementation, a linear programming model is established for each evaluation period. When the current evaluation period includes N new energy power stations and K out-of-limit objects, N decision variables are set.

[0089] The objective function of the linear programming model is:

[0090] The constraints of the linear programming model are:

[0091] in, The power limiting power of the i-th renewable energy power station is represented by the power limiting power. This indicates the degree of impact of the i-th renewable energy power station on the k-th over-limit object. This represents the amount of the violation corresponding to the k-th violation object. This represents the upper limit of the emission restriction corresponding to the i-th renewable energy power station. This represents the predicted active power value corresponding to the i-th renewable energy power station. N represents the number of renewable energy power stations, and K represents the number of objects exceeding the limit.

[0092] It should be noted that the over-limit reduction amount and the line over-limit amount corresponding to the line over-limit object are both in current dimension, while the over-limit reduction amount and the voltage over-limit amount corresponding to the voltage over-limit object are both in voltage per-unit dimension. Each matrix row is compared with the corresponding over-limit amount.

[0093] When the over-limit object is an empty set, the power limit of each new energy power station is set to zero to obtain the initial power limit scheme.

[0094] When the over-limit object is not empty, for each over-limit object, calculate the sum of the products of the degree of impact of all positive over-limit values ​​in the corresponding matrix row and the smaller of the upper limit of the power generation limit and the active power prediction value of the corresponding new energy power station.

[0095] When the sum of any of the products is less than the corresponding limit, output a state that no feasible launch scheme is possible and terminate the calculation for the current evaluation cycle.

[0096] When the sum of all the products is not less than the corresponding limit, the linear programming model is solved using the two-stage simplex method. The first stage uses artificial variables to determine if a feasible solution exists for the linear programming model; the second stage starts from the feasible solution and calculates the minimum value of the total power limit.

[0097] When the linear programming model has a feasible solution, the power limiting power of each new energy power station is output, and the power limiting power is combined according to the power station identification to obtain the initial power limiting scheme; when the linear programming model does not have a feasible solution, the state of no feasible power limiting scheme is output and the calculation of the current evaluation cycle is terminated.

[0098] For example, the over-limit amounts for line L2 and node N3 are 12.57 amperes and 0.00258 per-unit, respectively. Following the method in step S3, the over-limit impact levels of renewable energy power station A on line L2 and node N3 are obtained as 29.50 amperes per megawatt and 0.01250 per-unit per megawatt, respectively, and the over-limit impact levels of renewable energy power station B on line L2 and node N3 are obtained as zero amperes per megawatt and 0.00300 per-unit per megawatt, respectively, forming the over-limit impact matrix as follows:

[0099] The constraint requirement for line L2 is that the limited power generation of renewable energy power station A is not less than 12.57 divided by 29.50, which yields 0.4261017 MW. When the limited power generation of renewable energy power station A is 0.4261017 MW, the over-limit reduction at node N3 is 0.01250 multiplied by 0.4261017, yielding a per-unit value of 0.0053263. This is greater than the over-limit amount of 0.00258 per-unit value corresponding to node N3. Therefore, the limited power generation of renewable energy power station B is zero MW. Combining 0.4261017 MW and zero MW according to the power station identifier yields the initial power limiting scheme.

[0100] In step S5, candidate absorption power is calculated based on the initial power limiting scheme, power flow verification is performed on the candidate absorption power to obtain the power station absorption power, and the renewable energy absorption capacity of the distribution network is calculated based on the power station absorption power, including: The difference between the predicted active power of each new energy power station and the corresponding power limit for each assessment period is calculated to obtain the candidate power for absorption. Power flow calculations are performed based on the candidate absorption power, the reactive power setpoint, the active power load value, the reactive power load value, and the network parameters to obtain the verification power flow state; The power flow status is compared with the operating limits to obtain the over-limit objects and over-limit quantities. When the over-limit objects are empty, the candidate absorption power is determined as the power absorption power of the power station. When the over-limit objects are not empty, the over-limit influence matrix and the limited generation power are updated according to the over-limit objects and the over-limit quantities, and the candidate absorption power is updated. The power flow calculation and comparison are repeated until the updated over-limit objects are empty, and the updated candidate absorption power is determined as the power absorption power of the power station. The absorption power of each new energy power station within the same assessment period is summed to obtain the absorption power of the period. The power absorbed during the time period is calculated based on the power absorbed during the time period and the duration of the assessment period. The power absorbed during the time period within the assessment period is then accumulated to obtain the renewable energy absorption capacity of the distribution network.

[0101] In one implementation, the power limit corresponding to each renewable energy power station is read from the initial power limit scheme, and the difference between the active power prediction value and the power limit of the same renewable energy power station is calculated to obtain the candidate absorption power.

[0102] In this embodiment, the candidate absorption power is used to replace the corresponding active power prediction value, while keeping the reactive power setpoint, active power load value and reactive power load value unchanged. The node injection power is recalculated according to the method in step S1, and then the power flow verification state, the over-limit verification object and the over-limit verification amount are obtained according to the method in step S2.

[0103] When the verification limit object is empty, the current candidate absorption power is determined as the power absorbed by the power station.

[0104] When the checked over-limit object is not empty, the operating state corresponding to the current candidate absorption power is determined as the new disturbance starting point. For each renewable energy power station, the difference between the smaller value of the upper limit of power generation restriction and the active power prediction value and the already accumulated power generation restriction is calculated to obtain the remaining upper limit of power generation restriction.

[0105] When the remaining power generation limit of the new energy power station is greater than zero and the candidate absorption power is greater than zero, the degree of impact of the corresponding new energy power station on each of the verification over-limit objects is calculated according to the method in step S3.

[0106] When the remaining power generation limit of a new energy power station is zero, or the candidate power absorption capacity is zero, the matrix element in the column corresponding to the new energy power station in the updated over-limit impact matrix is ​​set to zero.

[0107] In this embodiment, the recalculated degree of the limit violation is arranged in a row for each of the aforementioned limit violation objects and a column for each new energy power station, to obtain the updated limit violation impact matrix.

[0108] Based on the updated over-limit impact matrix, the verified over-limit amount, and the remaining upper limit of the power restriction, a linear programming model corresponding to the newly added power restriction is established according to the method in step S4. Specifically, the newly added power restriction for each renewable energy power station is not less than zero, not greater than the corresponding remaining upper limit of the power restriction, and not greater than the corresponding candidate absorption power.

[0109] When the linear programming model has a feasible solution, the newly added restricted power is added to the already accumulated restricted power to obtain the updated restricted power; the updated restricted power is subtracted from the corresponding active power prediction value to obtain the updated candidate absorption power.

[0110] When the linear programming model has no feasible solution, the state of no feasible solution is output and the calculation of the current evaluation cycle is terminated.

[0111] Based on the updated candidate absorption power, power flow calculation and operation limit comparison are performed again to obtain the updated verification limit exceedance objects and the updated verification limit exceedance quantities.

[0112] When the updated verification limit-breaking object is empty, the updated candidate absorption power is determined as the power absorption power of the power station.

[0113] When the updated check limit violation object is not empty, the check limit violation object before the update and the updated check limit violation object are merged to obtain a comparison object set. For check limit violation objects that only exist before the update, the corresponding check limit violation quantity after the update is set to zero; for check limit violation objects that only exist after the update, the corresponding check limit violation quantity before the update is set to zero.

[0114] For each check limit violation object in the set of comparison objects, calculate the difference between the check limit violation amount before the update and the check limit violation amount after the update to obtain the check limit violation change amount.

[0115] When the change in the verified over-limit corresponding to at least one line over-limit object is greater than the recording accuracy of the branch current, or the change in the verified over-limit corresponding to at least one voltage over-limit object is greater than the recording accuracy of the node voltage, and all the changes in the verified over-limit are not less than the negative value of the corresponding recording accuracy, the operating state corresponding to the updated candidate absorption power is determined as the new disturbance starting point, and the over-limit influence matrix, the limited generation power, and the candidate absorption power are updated again.

[0116] When all the aforementioned check limit changes are not greater than the corresponding recording precision, or when any of the aforementioned check limit changes are less than the negative value of the corresponding recording precision, the output state of no effective improvement in the iteration is displayed and the calculation of the current evaluation cycle is terminated.

[0117] It should be noted that the linear programming solution, the cumulative power limit, and the update of the candidate absorption power use unrounded values. After the power flow verification is completed, the power limit and the power absorption power of the power station are displayed according to the number of digits in the result fields.

[0118] For example, the predicted active power of renewable energy power station A is 4.80 MW, and the power limiting in the initial power limiting scheme is 0.4261017 MW, resulting in a candidate absorption power of 4.3738983 MW. After power flow verification, the current amplitude of the verification branch of line L2 is 125.08 amperes, and the line current carrying limit is 125 amperes. The calculated over-limit of line L2 is 0.08 amperes.

[0119] Using the current operating state corresponding to the candidate absorption power as the starting point of the disturbance, the over-limit impact of renewable energy power station A on line L2 is recalculated to be 29.20 amperes per megawatt. Dividing 0.08 amperes by 29.20 amperes per megawatt, the newly added curtailed power corresponding to renewable energy power station A is 0.0027397 megawatts.

[0120] Adding the initial power restriction of 0.4261017 MW to the newly added power restriction of 0.0027397 MW yields the updated power restriction of 0.4288414 MW; subtracting 0.4288414 MW from the predicted active power of 4.80 MW yields the updated candidate absorption power of 4.3711586 MW.

[0121] After performing power flow calculations again, the checked over-limit objects are empty. The 4.3711586 MW of renewable energy power station A and the 2.60 MW of renewable energy power station B are determined as the power absorption capacity of the corresponding evaluation period, resulting in a power absorption capacity of 6.9711586 MW for the period.

[0122] When the evaluation period is 15 minutes, 15 minutes is converted to 0.25 hours. The power absorbed during the period is multiplied by 0.25 hours to obtain the power absorbed during the period as 1.7427897 megawatt-hours.

[0123] In this embodiment, the power consumption of each assessment period is calculated according to the order of the assessment periods. When the power consumption of each assessment period is obtained, the power consumption of all assessment periods is accumulated to obtain the renewable energy absorption capacity of the distribution network. When any assessment period outputs incomplete data, abnormal topology data, non-converged power flow calculation, no feasible power generation limitation scheme, or no effective improvement through iteration, the calculation of the current assessment cycle is terminated and the corresponding status is output.

[0124] In summary, this invention obtains the active power prediction value, reactive power setpoint value, and power generation limit of each renewable energy power station, as well as the active and reactive load values ​​of each node in the distribution network, the network parameters of the distribution network, and the operating limits. It then calculates the node-injected power and obtains the objects and quantities of power exceeding the limits. By progressively reducing the active power component in the node-injected power of each renewable energy power station's access node, it determines the degree of power exceeding the limits and constructs a power exceeding the limits influence matrix. Based on the power exceeding the limits influence matrix, the power exceeding the limits, and the power generation limit, it allocates the power generation limit of each renewable energy power station and performs power flow verification on the candidate absorption power. This achieves the allocation of power generation limit of multiple renewable energy power stations and the calculation of the renewable energy absorption capacity of the distribution network under the constraints of distribution network operating limits.

[0125] The second embodiment of the present invention provides a new energy absorption capacity calculation system for a power distribution network, comprising: a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor executes the program to implement the method described above.

[0126] It should be noted that the renewable energy absorption capacity calculation system for a distribution network provided in this embodiment of the invention is used to execute all the process steps of the renewable energy absorption capacity calculation method for a distribution network in the above embodiment. The working principles and beneficial effects of the two are one-to-one, so they will not be described again.

[0127] The specific embodiments described above further illustrate the purpose, technical solution, and beneficial effects of the present invention. It should be understood that the above descriptions are merely specific embodiments of the present invention and are not intended to limit the scope of protection of the present invention. In particular, it should be noted that any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention for those skilled in the art.

Claims

1. A method for calculating the renewable energy absorption capacity of a power distribution network, characterized in that, include: Obtain the active power prediction value, reactive power setpoint value, and power generation limit of each new energy power station, as well as the active power load value and reactive power load value of each node in the distribution network, the network parameters and operating limits of the distribution network, and calculate the node injection power based on the active power prediction value, the reactive power setpoint value, the active power load value and the reactive power load value; Power flow calculation is performed based on the node injection power and the network parameters to obtain the power flow state. The power flow state is then compared with the operating limits to obtain the objects and quantities that exceed the limits. The active component in the node injection power of each new energy power station access node is reduced one by one and power flow calculation is performed to obtain the over-limit change amount. The degree of over-limit impact is determined based on the over-limit change amount and an over-limit impact matrix is ​​constructed. Based on the over-limit impact matrix, the over-limit amount, and the upper limit of the power restriction, the power restriction power of each new energy power station is allocated according to the condition of eliminating the over-limit amount and minimizing the total power restriction power, so as to obtain the initial power restriction scheme; The candidate absorption power is calculated based on the initial power restriction scheme. The power flow is then checked against the candidate absorption power to obtain the power absorption power of the power plants. The renewable energy absorption capacity of the distribution network is then calculated based on the power absorption power of the power plants.

2. The method for calculating the renewable energy absorption capacity of a distribution network according to claim 1, characterized in that, The acquisition of the active power forecast, reactive power setpoint, and power generation limit of each new energy power station, as well as the active power load and reactive power load of each node in the distribution network, the network parameters and operating limits of the distribution network, includes: Obtain the active power prediction value, reactive power setting value, power generation limit and assessment period duration corresponding to each assessment period within the assessment cycle, as well as the active power load value and reactive power load value corresponding to each node of the distribution network; Obtain the access node of the power station, and perform time alignment of the active power prediction value, the reactive power set value, the active power load value and the reactive power load value according to the evaluation period within the evaluation cycle, and establish the correspondence between each new energy power station and each node of the distribution network based on the access node of the power station; Obtain the topology, line impedance, and reference voltage; associate the line impedance with the corresponding line based on the topology, and associate the reference voltage with the power node to obtain the network parameters; Obtain the line current carrying limit and the node voltage limit. Associate the line current carrying limit and the node voltage limit with the corresponding line and node respectively according to the line identifier and the node identifier to obtain the operating limit.

3. The method for calculating the renewable energy absorption capacity of a distribution network according to claim 2, characterized in that, The calculation of node injection power based on the active power prediction value, the reactive power setpoint, the active power load value, and the reactive power load value includes: Based on the power station access node, the active power predicted values ​​corresponding to the new energy power stations connected to the same node are summed to obtain the active power output of the node. Based on the power station access node, the reactive power setpoints corresponding to the new energy power stations connected to the same node are summed to obtain the node reactive power output; Set the active power output and reactive power output of the nodes that are not connected to the new energy power station to zero. The difference between the active power output of the node and the active load value of the corresponding node is calculated to obtain the active power injection of the node; the difference between the reactive power output of the node and the reactive load value of the corresponding node is calculated to obtain the reactive power injection of the node. The active power injection and reactive power injection of the node are combined to form the node injection power.

4. The method for calculating the renewable energy absorption capacity of a distribution network according to claim 3, characterized in that, The step of calculating the power flow state based on the node injection power and the network parameters includes: The initial node voltage is set according to the reference voltage, and the node current is calculated based on the node injected power and the initial node voltage. According to the topological relationship, the node currents are aggregated from the end node to the power node to obtain the branch current; Based on the branch current and the line impedance, the node voltage is updated from the power supply node to the terminal node; Repeatedly calculate the node current, the branch current, and the node voltage until the maximum difference between the corresponding node voltages in two adjacent calculations is not greater than a preset convergence threshold, thereby obtaining the power flow state including the branch current and the node voltage.

5. The method for calculating the renewable energy absorption capacity of a distribution network according to claim 4, characterized in that, The step of comparing the power flow state with the operating limit to obtain the object and amount of the violation includes: The amplitude of the branch current is compared with the current carrying limit of the corresponding line. Lines whose branch current amplitude is greater than the current carrying limit are identified as line over-limit objects. The difference between the amplitude of the branch current and the current carrying limit is calculated to obtain the line over-limit amount. The amplitude of the node voltage is compared with the upper limit of the node voltage of the corresponding node. Nodes whose amplitude of the node voltage is greater than the upper limit of the node voltage are identified as voltage over-limit objects. The difference between the amplitude of the node voltage and the upper limit of the node voltage is calculated to obtain the voltage over-limit amount. The line over-limit object and the voltage over-limit object are identified as the over-limit object, and the line over-limit amount and the voltage over-limit amount are identified as the over-limit amount.

6. The method for calculating the renewable energy absorption capacity of a distribution network according to claim 5, characterized in that, The process of progressively reducing the active power component in the node-injected power of each renewable energy power station access node and performing power flow calculations to obtain the over-limit change includes: Each new energy power station is sequentially identified as a target power station, and a disturbance step size is determined that is greater than zero and not greater than the smaller value between the upper limit of power generation restriction and the active power prediction value corresponding to the target power station. The disturbance step size is subtracted from the active power injection of the target power station access node, while keeping the active power injection of the remaining nodes unchanged, to obtain the disturbance active power injection. The disturbance active power injection and the node reactive power injection are combined to form the disturbance injection power; Power flow calculation is performed based on the disturbance injection power and the network parameters to obtain the disturbance power flow state. The disturbance power flow state is then compared with the operating limit to obtain the disturbance limit violation amount corresponding to the violation object. The difference between the over-limit amount and the disturbance over-limit amount is calculated to obtain the over-limit change amount.

7. The method for calculating the renewable energy absorption capacity of a distribution network according to claim 6, characterized in that, The step of determining the degree of influence of exceeding the limit based on the amount of change exceeding the limit and constructing the influence matrix of exceeding the limit includes: Calculate the ratio between the excess change amount and the disturbance step size corresponding to each of the target stations to obtain the degree of excess influence of each of the target stations on each of the excess objects; The degree of impact of exceeding the limit is arranged according to the arrangement that each of the aforementioned objects exceeds the limit corresponds to a row and each of the aforementioned new energy power stations corresponds to a column, so as to obtain the limit exceeding impact matrix.

8. The method for calculating the renewable energy absorption capacity of a distribution network according to claim 7, characterized in that, The process of allocating the power limitation of each renewable energy power station according to the condition of eliminating the over-limit and minimizing the total power limitation, to obtain the initial power limitation scheme, includes: The power limitation power of each new energy power station is set as a decision variable, and the power limitation power of each new energy power station is summed to obtain the total power limitation power. Based on the aforementioned over-limit impact matrix and the restricted power generation of each new energy power station, calculate the over-limit reduction amount corresponding to each over-limit object; The power generation limit of each new energy power station is limited to be no less than zero, no greater than the corresponding power generation limit, and no greater than the corresponding active power prediction value, and the over-limit reduction amount is limited to be no less than the corresponding over-limit amount; A linear programming model is established with the goal of minimizing the total power limit and with constraints on the power limit and the amount of power reduction exceeding the limit. Solve the linear programming model to obtain the power limiting power of each new energy power station, and combine the power limiting power of each new energy power station into the initial power limiting scheme.

9. The method for calculating the renewable energy absorption capacity of a distribution network according to claim 8, characterized in that, The process of calculating candidate absorption power based on the initial power restriction scheme, performing power flow verification on the candidate absorption power to obtain the power station absorption power, and calculating the renewable energy absorption capacity of the distribution network based on the power station absorption power includes: The difference between the predicted active power of each new energy power station and the corresponding power limit for each assessment period is calculated to obtain the candidate power for absorption. Power flow calculations are performed based on the candidate absorption power, the reactive power setpoint, the active power load value, the reactive power load value, and the network parameters to obtain the verification power flow state; The power flow status is compared with the operating limits to obtain the over-limit objects and over-limit quantities. When the over-limit objects are empty, the candidate absorption power is determined as the power absorption power of the power station. When the over-limit objects are not empty, the over-limit influence matrix and the limited generation power are updated according to the over-limit objects and the over-limit quantities, and the candidate absorption power is updated. The power flow calculation and comparison are repeated until the updated over-limit objects are empty, and the updated candidate absorption power is determined as the power absorption power of the power station. The absorption power of each new energy power station within the same assessment period is summed to obtain the absorption power of the period. The power absorbed during the time period is calculated based on the power absorbed during the time period and the duration of the assessment period. The power absorbed during the time period within the assessment period is then accumulated to obtain the renewable energy absorption capacity of the distribution network.

10. A system for calculating the renewable energy absorption capacity of a power distribution network, comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, characterized in that, When the processor executes the program, it implements the method according to any one of claims 1 to 9.

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