A power distribution network openable capacity standard calculation simulation method, system and application

Abstract

The application belongs to the technical field of power distribution network data processing, and discloses a power distribution network openable capacity standard calculation simulation method, a system and application. The simulation method comprises the following steps: obtaining data related to power distribution network openable capacity standard calculation; solidifying simulation boundary conditions related to power distribution network openable capacity standard calculation; simulating the maximum access capacity of distribution transformers, lines and substations respectively, and obtaining power distribution network equipment openable capacity calculation results. The application constructs a simulation model, carries out power distribution network equipment maximum access distributed power source capacity simulation in different scenes: according to a power distribution equipment openable capacity calculation method and principle, by adjusting line length, equipment capacity, load and its distribution, load rate and other parameters, the maximum access capacity of 10kV distribution transformers, 10kV lines and high-voltage substations is simulated in different scenes, and simulation results are obtained, which provide a reference for distributed power source access capacity.

Description

Technical Field

[0001] This invention belongs to the field of power distribution network data processing technology, and in particular relates to a method, system and application for calculating and simulating the open capacity standard of power distribution networks. Background Technology

[0002] Assessing the open capacity of distribution networks is a key challenge and a critical aspect of power grid planning and operation management. Excessive load or renewable energy connections to distribution network equipment can lead to heavy overload operation, causing safety hazards and reliability issues. Conversely, insufficient load or renewable energy connections can result in light-load operation, low equipment utilization, and wasted power resources.

[0003] Based on the above analysis, the problems and defects of the existing technology are as follows: (1) The existing technology cannot clearly define the data requirements involved in the calculation of the open capacity standard of the distribution network, and cannot accurately obtain the maximum access capacity information. (2) The existing technology cannot solidify the relevant boundary conditions for the calculation of the open capacity standard of the distribution network, and cannot accurately confirm the thermal stability limit load of 10kV lines and the simulation boundary conditions for the maximum access distributed power source of 10kV lines. (3) The existing technology does not combine the simulation of the maximum access capacity of distribution transformers, lines and substations in different scenarios, and cannot give typical calculation results of the open capacity of distribution network equipment. It cannot provide theoretical support for actual operation, resulting in poor equipment utilization and power resource utilization. Summary of the Invention

[0004] To overcome the problems existing in related technologies, the present invention discloses an embodiment of a method, system and application for calculating and simulating the open capacity standard of a distribution network.

[0005] The technical solution is as follows: a method for calculating and simulating the open capacity standard of a distribution network, characterized in that the method includes the following steps:

[0006] S1, Obtain the data involved in the calculation of the open capacity standard of the distribution network; the data includes: historical operating data, operating equipment parameters, actual power grid data, power grid and new energy data, construction planning data of distributed power sources, geographical location data, power grid structure data, operating mode data, load type data, load level data, and time scale data;

[0007] S2, solidify the boundary conditions for calculating and simulating the open capacity standard of the distribution network; the boundary conditions include: the maximum load rate of distribution network equipment, voltage deviation, allowable value of harmonic current, allowable value of short-circuit current, line thermal stability limit load and the maximum number of distributed power sources connected to the line;

[0008] S3 simulates the maximum access capacity for different scenarios involving power lines, distribution transformers, and substations, obtaining the calculation results for the open capacity of distribution network equipment. The simulation of the maximum access capacity for power lines includes: constructing the load distribution functions for each load distribution model sequentially, based on uniform load distribution models, decreasing load distribution models, increasing load distribution models, increasing-then-decreasing load distribution models, and decreasing-then-increasing load distribution models.

[0009] p(x) = P / L;

[0010] p(x) = 2P·x / L 2 ;

[0011] p(x)=2P·(Lx) / L 2 ;

[0012]

[0013]

[0014] p(x) is the three-phase power (i.e., three-phase load density) at the load point x km from the beginning of the line (kW*km). -1 P is the three-phase active power transmitted at the beginning of the line (kW), x is the distance from the beginning of the line (km), and L is the total length of the line (km).

[0015] The simulation of the maximum grid connection capacity of the distribution transformer includes: distributed photovoltaic capacity ratio = distributed photovoltaic capacity / 10kV distribution transformer capacity × 100%.

[0016] Simulation of the maximum access capacity of the substation includes: grid-side energy storage capacity configuration: by reducing the substation load rate and peak shaving and valley filling to reduce the peak-valley difference rate of the grid load, the energy storage capacity configuration for substation load reduction and peak shaving and valley filling is carried out.

[0017] Energy storage capacity configuration on the power supply side: The energy storage capacity configuration on the new energy side in the region is estimated by using a sample estimation method to estimate the overall capacity.

[0018] User-side energy storage capacity configuration: The user-side energy storage capacity configuration in the region is estimated using a sample estimation method.

[0019] Another objective of this invention is to provide a system for implementing the method for calculating and simulating the openable capacity standard of the distribution network, the system comprising:

[0020] The data acquisition module is used to acquire data involved in the calculation of the open capacity standard of the distribution network; the data includes: historical operating data, operating equipment parameters, actual power grid data, construction planning data of the power grid and new energy sources and distributed power sources, geographical location, power grid structure, operating mode, load type, load level and time scale data;

[0021] The simulation boundary condition solidification module is used to solidify the simulation boundary conditions related to the calculation of the open capacity standard of the distribution network. The boundary conditions include the maximum load rate of distribution network equipment, voltage deviation, allowable value of harmonic current, allowable value of short-circuit current, line thermal stability limit load, and maximum number of distributed power sources connected to the line.

[0022] The scenario-specific simulation calculation module is used to simulate the maximum access capacity of distribution transformers, lines, and substations in different scenarios to obtain the calculation results of the open capacity of distribution network equipment.

[0023] Another object of the present invention is to provide a computer device, the computer device including a memory and a processor, the memory storing a computer program, which, when executed by the processor, causes the processor to perform the above-described method for calculating and simulating the open capacity standard of the distribution network.

[0024] Another object of the present invention is to provide a computer-readable storage medium storing a computer program, which, when executed by a processor, causes the processor to perform the aforementioned method for calculating and simulating the open capacity standard of a power distribution network.

[0025] Combining all the above technical solutions, the advantages and positive effects of this invention are as follows:

[0026] First, in view of the technical problems existing in the prior art and the difficulty of solving these problems, and closely combining the technical solution to be protected by this invention with the results and data during the research and development process, this paper analyzes in detail how the technical solution of this invention solves the technical problems, and the inventive technical effects brought about after solving the problems, as described in detail below:

[0027] This invention outlines the data requirements for calculating the standard open capacity of distribution networks, analyzes the calculation principles from aspects such as the maximum load rate of distribution network equipment, voltage deviation, and allowable harmonic current values, and uses active distribution network integrated analysis system tools for simulation based on relevant data and principles to calculate the open capacity results of typical distribution network equipment. This invention helps to rationally and efficiently utilize power grid resources and scientifically guide the orderly access of diversified loads and new energy sources.

[0028] Secondly, considering the technical solution as a whole or from the perspective of the product, the technical effects and advantages of the technical solution to be protected by this invention are specifically described as follows: This invention constructs a simulation model to conduct simulations of the maximum access capacity of distributed power sources for distribution network equipment in different scenarios: Based on the calculation method and principle of the open capacity of distribution equipment, by adjusting parameters such as line length, equipment capacity, load and its distribution, and load rate, the maximum access capacity of 10kV distribution transformers, 10kV lines, and high-voltage substations is simulated in different scenarios, and the simulation results are obtained to provide a reference for the access capacity of distributed power sources. Attached Figure Description

[0029] The accompanying drawings, which are incorporated in and form a part of this specification, illustrate embodiments consistent with this disclosure and, together with the description, serve to explain the principles of this disclosure.

[0030] Figure 1 This is a flowchart of the openable capacity calculation method for distribution networks based on big data, provided in an embodiment of the present invention.

[0031] Figure 2 This is a uniform load distribution curve provided in an embodiment of the present invention;

[0032] Figure 3 This is a decreasing load distribution curve provided in an embodiment of the present invention;

[0033] Figure 4 This is an incremental load distribution curve provided in an embodiment of the present invention;

[0034] Figure 5 This is a load distribution curve diagram with an increase followed by a decrease provided in this embodiment of the invention;

[0035] Figure 6 This is a load distribution curve diagram of first decreasing and then increasing provided in the embodiments of the present invention;

[0036] Figure 7 This is a simulation model diagram of a 400kVA distribution transformer provided in an embodiment of the present invention;

[0037] Figure 8 This is a simulation model diagram of a 1600VA distribution transformer provided in an embodiment of the present invention;

[0038] Figure 9 This is a simulation diagram of the maximum access of a 10kV line to a distributed photovoltaic system provided in an embodiment of the present invention;

[0039] Figure 10 This is a schematic diagram of the power distribution network open capacity standard calculation and simulation system provided in this embodiment of the invention;

[0040] Figure 11 Simulation diagram of the maximum number of distributed photovoltaic power plants connected to a high-voltage substation;

[0041] In the diagram: 1. Data acquisition module; 2. Simulation boundary condition fixing module; 3. Scene-specific simulation calculation module. Detailed Implementation

[0042] To make the above-mentioned objects, features, and advantages of the present invention more apparent and understandable, specific embodiments of the present invention will be described in detail below with reference to the accompanying drawings. Many specific details are set forth in the following description to provide a thorough understanding of the present invention. However, the present invention can be practiced in many other ways different from those described herein, and those skilled in the art can make similar modifications without departing from the spirit of the present invention. Therefore, the present invention is not limited to the specific embodiments disclosed below.

[0043] I. Explanation of the Implementation Example:

[0044] like Figure 1 As shown, this embodiment of the invention provides a method for calculating and simulating the standard open capacity of a distribution network, including the following steps:

[0045] S101, Obtain the data involved in the calculation of the open capacity standard of the distribution network;

[0046] The data includes: historical operating data, operating equipment parameters, actual power grid data, construction planning data for power grid and new energy sources and distributed power sources, geographical location, power grid structure, operating mode, load type, load level and time scale data;

[0047] S102, Fixed simulation boundary conditions for calculating the open capacity standard of the distribution network;

[0048] Boundary conditions include the maximum load rate of distribution network equipment, voltage deviation, allowable harmonic current, allowable short-circuit current, line thermal stability limit load, and maximum number of distributed power sources connected to the line.

[0049] S103 simulates the maximum access capacity for different scenarios of distribution transformers, lines, and substations to obtain the calculation results of the open capacity of distribution network equipment.

[0050] Example 1

[0051] The method for calculating the openable capacity of a distribution network based on big data, provided in this embodiment of the invention, includes the following steps:

[0052] This invention, through analyzing the development of new energy sources, the capacity of distribution networks to accept new energy sources, and existing analytical results on the available capacity of distribution networks, points out the direction for improving the calculation model of available capacity of distribution networks under the new power system by analyzing the traditional calculation method of available capacity of distribution networks and its shortcomings.

[0053] This paper addresses the impact of large-scale distributed generation access on the distribution network's operational characteristics. Based on the distribution network power flow optimization results, it analyzes the intrinsic relationship between the distribution network's open capacity and factors such as bay resources, capacity resources, network structure, operational constraints, and flexibility resources using an influencing factor analysis method. This provides a theoretical basis for selecting the open access capacity of the distribution network.

[0054] Based on the factors affecting the open capacity of the distribution network, this paper analyzes the calculation methods for the open capacity of lines and distribution transformers connected to loads and distributed generation, and proposes corresponding mathematical models, calculation processes, and data requirements. Specifically, load connection mainly analyzes constraints such as N-1 throughput and heavy overload conditions; photovoltaic connection mainly analyzes constraints such as voltage deviation, network loss, harmonics, and three-phase imbalance.

[0055] Based on the calculation method of open capacity of power distribution equipment, this paper comprehensively analyzes the current status of the power distribution network, new energy planning and power grid planning information, and constructs an assessment model of the open capacity of the power distribution system. It proposes an optimization solution method for the assessment model to obtain the open capacity of the power distribution system and the system operation simulation results. According to the calculation process of the open capacity of the power distribution system, it proposes a method for acquiring and integrating demand data.

[0056] This paper outlines the data requirements for calculating the standard open capacity of distribution networks, analyzes the calculation principles from aspects such as the maximum load rate of distribution network equipment, voltage deviation, and allowable harmonic current, and uses the active distribution network integrated analysis system tool to perform simulation based on relevant data and principles, and calculates typical results of the open capacity of distribution network equipment.

[0057] The embodiments of this invention select typical regions and conduct empirical applications of the results to verify their scientific validity, effectiveness, and practicality.

[0058] The technical solution of this invention will be further described below in conjunction with the method for calculating the open capacity of distribution network equipment.

[0059] 1. Calculation method for open capacity of distribution network equipment under normal circumstances

[0060] Under normal circumstances, the calculation of the open capacity of distribution network equipment is mainly divided into the calculation of the open capacity of 10kV distribution transformers, the open capacity of 10kV lines, and the open capacity of high-voltage substations. Specifically, the open capacity of 10kV distribution transformers should not exceed the open capacity of 10kV lines, and the open capacity of 10kV lines should not exceed the open capacity of high-voltage substations. Factors affecting the open capacity of distribution network equipment under normal circumstances mainly include load factor, power supply capacity, power factor, and load.

[0061] 2. Calculation method for open capacity of 10kV distribution transformer under normal circumstances

[0062] Under normal circumstances, 10kV distribution transformers cannot operate under heavy load. The maximum load rate of a 10kV distribution transformer can reach 80%. Therefore, the formula for calculating the open capacity of a 10kV distribution transformer is as follows:

[0063]

[0064] In the formula, k pb For the open capacity of the 10kV distribution transformer, α pb This represents the maximum load factor of a 10kV distribution transformer, typically taken as 80%; R pb For 10kV distribution transformer capacity; δ pb The power factor for a 10kV distribution transformer is typically taken as 0.9; P pb The 10kV distribution transformer already has its maximum load.

[0065] 3. Calculation method for open capacity of 10kV lines under normal circumstances

[0066] The formula for calculating the open capacity of a 10kV line under normal circumstances is as follows:

[0067]

[0068] In the formula, k zxl Open capacity for 10kV lines; U zxlN I represents the nominal voltage of the 10kV line; I represents the safe current of the 10kV line; δ zxl The power factor is typically taken as 0.95; α zxl The maximum load factor for a 10kV line is 50% for a single tie line, 66.67% for two tie lines, 75% for three tie lines, and 80% for a single radial line. zxl This represents the maximum existing load on the 10kV line.

[0069] 4. Calculation method for open capacity of high-voltage substation under normal circumstances

[0070] 4.1 Calculation method for maximum load rate of main transformer in high-voltage substation

[0071] (1) Typical interconnection model of substation

[0072] A typical substation interconnection model refers to a power supply model formed by combining different main transformer configurations within substations with different numbers of interconnected substations, and connecting the substations with 10kV lines. According to the State Grid Corporation of China's "Research on Typical Power Supply Modes of Distribution Networks," within the same power supply module, any main transformer in a substation is only interconnected with one main transformer in the opposite substation. This interconnection mode has a clear structure, well-defined power transfer, requires fewer lines, and has a high theoretical load factor under the condition of "N-1". Therefore, the established interconnection model can be based on this symmetrical interconnection structure.

[0073] In summary, based on the symmetrical interconnection structure, typical interconnection models are established by selecting 2 to 3 main transformers in the substation and single, double, and triple interconnections for the 10kV lines.

[0074] Meanwhile, the number of interconnected substations selected in this invention is 2 to 4. When there are more substations in the same power supply block, the established typical interconnection model can be expanded. For example, in the case of a ring power supply of N substations, each substation is only connected to the two adjacent substations, which can be classified into a typical substation interconnection model of three interconnected substations.

[0075] To simplify the analysis, the two dimensions of the number of interconnected substations and the configuration of main transformers within the substation are merged into a "substation-main transformer" (m×n) combination mode. There are six combinations of "substation-main transformer" (m×n): 2×2, 2×3, 3×2, 3×3, 4×2, and 4×3.

[0076] The main transformer interconnection relationships within a substation, the main transformer configuration in the substation interconnection model, and the number of substations all affect the main transformer load rate of the substation. Therefore, for a given substation configuration, once the main electrical wiring method within the substation is determined, the ideal load rate of the substation's main transformers can be calculated.

[0077] Analysis of the main electrical wiring configuration of urban substations in China shows that the current configuration of main transformers in high-voltage substations is typically 2 to 3 units.

[0078] The main wiring configuration on the low-voltage side within the substation is described below:

[0079] When a high-voltage substation is configured with two main transformers, its low-voltage side generally adopts a single busbar segmented connection mode.

[0080] In this wiring configuration, if any main transformer in the station fails, its load can be transferred to another main transformer in the station via the bus tie switch.

[0081] When a high-voltage substation is configured with three main transformers, its low-voltage side can adopt a single busbar four-section connection mode.

[0082] In this wiring configuration, if the substation is not equipped with an automatic tripping device, when one of the main transformers in the middle fails, its load can be shared by the main transformers on both sides. However, if both main transformers on both sides fail, only the middle main transformer can share the load. If the substation is equipped with an automatic tripping device, when any one of the main transformers in the substation fails, the other two main transformers can share the load of the failed transformer.

[0083] When a high-voltage substation is configured with three main transformers, its low-voltage side can also adopt a single busbar six-section wiring mode.

[0084] In this wiring configuration, if any one main transformer in the station fails, its load can be equally distributed to the other two main transformers in the station. Therefore, when there are three main transformers, the four-section busbar wiring with self-tripping device is the same as the six-section busbar ring wiring; when any one main transformer in the station fails, its load can be equally distributed to the other two main transformers in the station.

[0085] (2) Value of maximum load rate of main transformer in substation

[0086] To satisfy the "N-1" check of the main transformer, there are two transfer methods for a faulty main transformer: direct and indirect. Direct transfer involves transferring the load to a directly connected main transformer at the same or different substations. Indirect transfer utilizes the overload capacity of a substation-connected main transformer to transfer the overloaded portion of the load to a main transformer with which it has an inter-substation connection. The final state of both transfer methods should ensure that no main transformer is overloaded.

[0087] 4.2 Calculation method for open capacity of high-voltage substation under normal circumstances

[0088] The formula for calculating the open capacity of a high-voltage substation under normal circumstances is as follows:

[0089]

[0090] In the formula, k gb Open capacity for high-voltage substations; α gb This represents the maximum load factor of the high-voltage substation; δ gb The power factor for high-voltage substations is typically taken as 0.98; R gb For the capacity of the high-voltage substation; P gb The high-voltage substation is already at its maximum load.

[0091] 4.3 Calculation Method for Open Capacity of Distribution Network Equipment Based on New Power System

[0092] 4.3.1 Maximum Acceptance Capacity of Distributed Power Generation in Distribution Network Equipment

[0093] 1) Maximum acceptance capacity of 10kV distribution transformers for distributed generation

[0094] The maximum capacity for distribution transformers to connect to distributed photovoltaic systems mainly depends on the transformer capacity, transformer load size, non-overload operation during reverse power flow, and voltage deviation meeting the guidelines.

[0095] The calculation method for the maximum distributed photovoltaic capacity that a distribution transformer can connect to is as follows:

[0096] P pbf -P pbmin =α pb R pb δ pb (4)

[0097]

[0098] In the formula, P pbf This refers to the maximum capacity of a 10kV distribution transformer connected to a distributed power source; P pbmin The minimum daily load of the 10kV distribution transformer in the baseline year; α pb For 10kV distribution transformer load factor, the value is generally less than or equal to 80%; R pb For 10kV distribution transformer capacity; δ pb The power factor for a 10kV distribution transformer is typically taken as 0.9; U pbf To connect the distributed photovoltaic system to the low-voltage side bus voltage of the distribution transformer; U pbN This refers to the voltage of the low-voltage side busbar of the distribution transformer.

[0099] Maximum acceptance capacity of 10kV lines for distributed generation

[0100] The maximum capacity of 10kV distributed photovoltaic power transmission mainly depends on the power supply capacity of the 10kV line, the load size of the 10kV line, the N-1 reverse power flow operation requirements (non-heavy load operation requirements), and the voltage deviation must meet the guidelines.

[0101]

[0102]

[0103] In the formula, P zxlf The maximum capacity of distributed power sources that can be connected to a 10kV line; P zxlmin This refers to the minimum daily load of a 10kV line in the baseline year; U zxlN I is the nominal voltage of 10 kV; I is the safe current of the 10 kV line; δ zxl The power factor is typically taken as 0.95; α zxl The maximum load factor for a 10kV line is 50% for a single tie line, 66.67% for two tie lines, 75% for three tie lines, and 80% for a single radial line. zxlif The voltage after each 10kV line segment is connected to a distributed power source is denoted by i, where i represents the segment of the 10kV line, which is generally less than or equal to 5.

[0104] 4.3.2 Maximum capacity of high-voltage substations to accommodate distributed power sources

[0105] The maximum capacity for distributed photovoltaic power to be connected to a high-voltage substation mainly depends on the power supply capacity of the high-voltage substation, the load size of the high-voltage substation, the N-1 reverse power flow operation requirements (non-heavy load operation requirements), and the short-circuit current, voltage deviation, and voltage quality meeting the guidelines.

[0106] P gbf -P gbmin =αgb R gb δ gb (8)

[0107] I xz >I m (9)

[0108]

[0109] I xzh >I h (11)

[0110] In the formula, P gbf P represents the maximum capacity of distributed power sources that can be connected to a high-voltage substation. zxlmin The minimum daily load of the high-voltage substation in the baseline year; α gb For a high-voltage substation to meet the maximum load factor under the condition of N-1; δ gb The power factor for high-voltage substations is typically taken as 0.98; R gb For the capacity of the high-voltage substation; I xz For the system bus short-circuit current; I m The allowable short-circuit current value; U gbf This refers to the voltage value after connection to the high-voltage substation; U gbN This refers to the nominal voltage value of a high-voltage substation; I xzh The value of the h-th harmonic current; I h The limit for the h-th harmonic current as specified in GB / T 14549.

[0111] 4.4 Open Capacity of Distribution Network Equipment Based on New Power Systems

[0112] Distribution network equipment based on the new power system will be connected to flexible resources such as distributed power sources and energy storage. These factors will increase the power supply capacity of the distribution network equipment, thereby increasing the available capacity of the distribution network equipment.

[0113] Considering distributed power sources and energy storage, the formula for calculating the open capacity of a 10kV distribution transformer is as follows:

[0114]

[0115] In the formula, k xpb To consider the open capacity of 10kV distribution transformers with flexible resources; α pb This represents the maximum load factor of a 10kV distribution transformer, typically taken as 80%; R pb For 10kV distribution transformer capacity; δ pb The power factor for a 10kV distribution transformer is typically taken as 0.9; P pb The 10kV distribution transformer already has its maximum load; P pbfc This refers to the output of distributed generation under maximum load conditions for a 10kV distribution transformer; Ppbc This refers to the energy storage capacity to reduce load under maximum load conditions for a 10kV distribution transformer.

[0116] Considering distributed power sources and energy storage, the formula for calculating the open capacity of a 10kV line is as follows:

[0117]

[0118] In the formula, k zxl Open capacity for 10kV lines; U zxlN I represents the nominal voltage of the 10kV line; I represents the safe current of the 10kV line; δ zxl The power factor is typically taken as 0.95; α zxl The maximum load factor for a 10kV line is 50% for a single tie line, 66.67% for two tie lines, 75% for three tie lines, and 80% for a single radial line. zxl This represents the maximum existing load on the 10kV line. (P) zxlfc The output of distributed generation under maximum load conditions for a 10kV line; P zxlc This provides the energy storage capacity to reduce load under maximum load conditions for 10kV lines.

[0119] Considering the factors of distributed power sources and energy storage, the formula for calculating the open capacity of high-voltage substations is as follows:

[0120]

[0121] In the formula, k gb Open capacity for high-voltage substations; α gb This represents the maximum load factor of the high-voltage substation; δ gb The power factor for high-voltage substations is typically taken as 0.98; R gb For the capacity of the high-voltage substation; P gb The high-voltage substation already has its maximum load; P gbfc For distributed power output under maximum load conditions at high-voltage substations; P gbc This refers to the energy storage capacity to reduce load under maximum load conditions at high-voltage substations.

[0122] 4.5 Calculation Method for Open Capacity of Power Distribution System

[0123] 4.5.1 Calculation method for the open capacity of a power distribution system under normal circumstances

[0124] Under normal circumstances, the open capacity of a power distribution system is the sum of the open capacities of high-voltage substations. Therefore, the formula for calculating the open capacity of a power distribution system is as follows:

[0125]

[0126] In this system, the total open capacity of the lines connected to a single substation shall not exceed the total open capacity of that substation, i.e.:

[0127]

[0128] The total open capacity of the transformers connected to a single line in a power distribution system shall not exceed the open capacity of that line, that is:

[0129]

[0130] In the formula, k cpx This refers to the capacity that can be opened up in the power distribution system under normal circumstances; k gbi k represents the available capacity of the i-th high-voltage substation. gb For the available capacity of high-voltage substations; k zxlj The available capacity of the j-th 10kV line; k zxl The available capacity for a 10kV line; k pbe The available capacity for the e-th 10kV distribution transformer.

[0131] 4.5.2 Calculation Method for Open Capacity of Distribution Network for New Power Systems

[0132] In addition to the open capacity of the distribution system under normal circumstances, the active distribution network for the new power system also needs to consider the interruptible loads reduced by demand-side management, as well as the superposition of open capacity brought about by the access of distributed power sources and energy storage to the distribution system. Therefore, the calculation formula for the open capacity of the active distribution network for the new power system is as follows:

[0133] k1=k cpx +ΔP+P x +S c

[0134] In the formula, ΔP represents the interruptible load reduced through demand response; P x Power output from new energy sources under maximum regional load conditions; S c This provides the power distribution system with the capacity to reduce load under maximum regional load conditions through energy storage.

[0135] 1) Calculation method for demand response reduction of interruptible load

[0136] P kz =αP xkz

[0137] In the formula, P kz Interruptible loads are available to respond to demand.

[0138] α is the demand response coefficient;

[0139] P xkz The total interruptible load resources required to meet demand, as determined in consultation with users.

[0140] Demand-side flexible resources can proactively participate in the power grid for economic regulation purposes, cooperating with the distribution network. They can be transferred in time or space and have many potential types. However, due to constraints such as price, incentive mechanisms, and infrastructure, their implementation scale is relatively small and their implementation methods are relatively simple. As an important resource for demand response, demand-side flexible resources are mainly divided into four categories: flexible resources for electric vehicles, flexible resources for industrial users, flexible resources for commercial users, and flexible resources for residential users.

[0141] (1) Electric vehicle resource balancing

[0142] Electric vehicles participate in grid dispatch in the form of charging and battery swapping stations, serving as transferable loads. The demand response coefficient for electric vehicles is approximately 0.2 to 0.6.

[0143] (2) Flexible resources for industrial users

[0144] Industrial users, as flexible resources, typically have large electricity demands, relatively stable loads with small peak-to-valley differences, high speed, and high levels of intelligence, making them important flexible loads in the power system. Based on electricity consumption habits, high-energy-consuming industrial loads can be distributed as interruptible loads and shiftable loads. Shiftable loads are specifically designed for large industrial enterprises with adjustable shift schedules. The power grid signs contracts with these users, allowing them to accept grid dispatch orders and schedule their work during the contract period. The demand response coefficient for shiftable industrial users is approximately 0.3–0.5. Interruptible loads mainly consist of less critical loads in industrial production, addressing loads with low power quality by reducing load demand to improve user electricity demand and reduce peak-to-valley differences. The demand response coefficient for shiftable industrial users is approximately 0.6–0.8.

[0145] (3) Flexible resources for business users

[0146] Large commercial users have large electricity capacities and concentrated electricity consumption times, making dispatching less flexible and load transfer difficult. The loads that large commercial users can participate in grid dispatching mainly include building exterior lights, electric vehicles within the building area, and central air conditioning systems. To reduce load, loads are reduced during peak periods to decrease average power consumption. The demand response coefficient for commercial users is approximately 0.6 to 0.8.

[0147] (4) Flexible resources for residential users

[0148] Approximately 60% of residential load can be considered flexible loads, allowing for adjustments to electricity consumption patterns and participation in grid dispatch under controlled guidance. Flexible load devices include smart air conditioners, lighting, washing machines, rice cookers, and electric vehicles. The demand response coefficient for residential users is approximately 0.5 to 0.7.

[0149] (ii) Characteristics of New Energy Output

[0150] (1) Output characteristics of hydroelectric power plants

[0151] Due to the peak-valley price difference in power generation, hydropower often generates electricity during the day, causing backfeed peaks. Analysis of daily power output characteristics shows that hydropower stations have lower output before 7:00 AM and higher output between 7:00 PM and 9:00 PM, corresponding to periods of lower and higher system loads, respectively. Hydropower station output is lower in autumn and winter than in spring and summer.

[0152] (2) Output characteristics of photovoltaic power plants

[0153] Photovoltaic power output varies with natural factors such as sunlight intensity, weather, season, and temperature, exhibiting random fluctuations. Photovoltaic power output is mostly concentrated during the day, especially at midday, while output is zero at night, showing significant temporal characteristics and making it impossible to provide a continuous and stable power supply.

[0154] From the perspective of short-term and daily power output characteristics, photovoltaic (PV) power output exhibits strong fluctuations and significant time-dependent variations. The timing of maximum PV output varies slightly across different seasons, but the variation is not significant. Typical daily PV output occurs between 7:00 AM and 5:00 PM, concentrated during the daytime, especially midday, while nighttime output is zero, failing to provide a continuous and stable power supply. PV power output has a high degree of matching with daytime load, exhibiting positive peak-shaving characteristics; however, due to the difficulty in generating power at night, it is difficult to effectively match the evening peak load.

[0155] In terms of annual output characteristics, photovoltaic power generation exhibits obvious seasonality, with higher power generation in spring and autumn, and output less than 50% of its installed capacity for most of the year. While daily photovoltaic output is similar but varies throughout the year, this reflects the cyclical and non-stationary nature of photovoltaic output.

[0156] (3) Output characteristics of wind power plants

[0157] Wind power output varies significantly across hours, days, and months throughout the year, exhibiting marked discontinuities and abrupt changes with no discernible pattern. In terms of daily output characteristics, it generally shows a trend of lower output during the day and higher output at night, with the daily variation in wind power density largely consistent with wind speed. Regarding daily characteristics, the daily output curve exhibits a "peak and trough" pattern, with the highest output between 1:00 and 8:00 AM and the lowest between 12:00 and 5:00 PM. The average output during the day (10:00 AM to 6:00 PM) is lower than the average output during the night (6:00 PM to 6:00 AM the following day).

[0158] Due to the intermittent, random, and fluctuating nature of wind power, as well as the inherent characteristics of wind farms (such as wind speed variations, wind shear, yaw error, and tower shadow effects), the input wind energy of wind turbines is unstable, leading to random fluctuations in wind power output. This can potentially cause system frequency stability issues. Therefore, when considering system power output arrangements and reserve capacity, the impact of wind power needs to be factored in, and a corresponding energy storage system is required to achieve smooth output.

[0159] 4.6 Energy Storage Capacity Configuration Method

[0160] (1) Grid-side energy storage capacity configuration method

[0161] The main considerations for grid-side energy storage are to reduce the load rate of substations and to reduce the peak-valley difference rate of grid load. A method for configuring energy storage capacity for substation load reduction and peak shaving and valley filling is proposed.

[0162] 1) Energy storage capacity configuration method for reducing substation load

[0163] The substation has a high load rate. If the maximum load rate of the substation exceeds 90%, it will seriously threaten the safe operation of the substation. The power of the energy storage equipment needs to be considered from two factors: 1) ensuring the operation of important loads; 2) the transformer cannot be under heavy load.

[0164] The formula for calculating energy storage capacity is as follows:

[0165] P BESS =max{max{P(t)-P OL};P C}

[0166] In the formula: P BESS P(t) represents the configured power value for energy storage; P(t) represents the real-time load power value; P OL P is the heavy-load power threshold for the substation. C The power rating of the critical load.

[0167] Based on the above energy storage power selection values, the energy storage capacity configuration also needs to consider: the substation's heavy load time; and the time required for one cycle of important load operation.

[0168] The formula for calculating energy storage capacity is as follows:

[0169] E BESS =P BESS ×max{T OL ;T C}

[0170] In the formula: E BESS Select the configuration capacity value for energy storage; P BESS Select the configuration power value for energy storage; TOL T represents the overload time of the substation. C This refers to the operating cycle of critical loads.

[0171] 2) Energy storage capacity configuration methods for peak shaving and valley filling

[0172] Peak shaving and valley filling are fundamental issues in power grid operation. Most thermal power units lack sufficient regulation capacity. Hydropower units offer flexible operation and rapid start-up and shutdown, with a regulation range approaching 100%, but their construction site selection is entirely dependent on geographical conditions. Energy storage, due to its rapid response and lack of geographical limitations, can meet the large-scale peak shaving and valley filling needs of the power grid.

[0173] The power of energy storage used for peak shaving and valley filling should be taken as the maximum power limit for grid peak regulation. The formula for calculating energy storage power is as follows:

[0174] P BESS =max{|ΔP1|,|ΔP2|,…,|ΔP N |}

[0175] In the formula: P BESS The power selection value for the energy storage system; |ΔP i |(i=1,2,…,N) represents the output demand value of the energy storage system calculated at each time point.

[0176] Based on the above determined energy storage power values, the energy storage capacity is selected as shown in the formula.

[0177] E BESS =max{N1,N2}

[0178] N1=max{|ΔP1ΔT|,|ΔP1ΔT+ΔP2ΔT|,…,|ΔP1ΔT+ΔP2ΔT+…+ΔP N ΔT|}

[0179]

[0180] In the formula: E BESS The capacity of the energy storage system is selected; ΔT is the data sampling time interval; 1~m1, m2~m3, ..., m j ~m n This refers to the time period during which the energy storage is in a charging and discharging state.

[0181] Generally, the energy storage capacity of the grid side is determined according to the power and time required to reduce the maximum load of the high-voltage substation to below 65% for 2 to 4 hours, and the energy storage access line is determined according to the load rate that meets "N-1".

[0182] (2) Energy storage capacity configuration method on the power supply side

[0183] The inherent intermittent nature of new energy sources makes their output unpredictable, which is detrimental to the stable operation of the power grid. Energy storage has the ability to quickly and bidirectionally adjust output, which can smooth out fluctuations in new energy output and make it more consistent. The primary consideration in configuring energy storage devices on the new energy side is to mitigate the volatility of new energy output.

[0184] The capacity configuration of energy storage on the renewable energy side is closely related to the power generation data of renewable energy sources. Based on the renewable energy output data and the required rate of change of grid-connected active power, the energy storage power variation range curve can be obtained, namely:

[0185] |P BESS,k |≤ΔP wmax -ΔP max

[0186] In the formula: P BESS,k ΔP represents the output power at time k of energy storage. wmax To smooth out the maximum power fluctuation value in the first 10 minutes; ΔP max This refers to the maximum allowable change in the power input from new energy sources to the grid within 10 minutes.

[0187] The power demand for energy storage follows a normal distribution. According to the 3δ principle of the normal distribution, approximately 99.7% of the cases fall within the interval μ+3δ. This means that the energy storage system's output power is required to mitigate fluctuations in renewable energy power in 99.7% of the cases. The formula for calculating energy storage power is as follows:

[0188] P BESS =max{|μ-3δ|,|μ+3δ|}

[0189]

[0190]

[0191] In the formula: P BESS Select a value for energy storage capacity; denoted as the average energy storage power; K is the sample size; μ and δ are the mean and standard deviation of the sample data, respectively.

[0192] Given that energy storage capacity configuration calculation based on historical output data is essentially an estimation method, the aforementioned energy storage power P... BESS Multiplying by the number of hours of continuous energy storage output ΔT, the formula for calculating energy storage capacity is as follows:

[0193] E BESS =P BESS ΔT

[0194] For the calculation of the energy storage capacity configuration of new energy sources in the region, considering the large number of new energy sources in the region, the sample estimation method can be used to estimate the overall energy storage capacity configuration of new energy sources in the region.

[0195] The estimation of energy storage capacity configuration on the new energy side within the region can be carried out according to the following steps:

[0196] 1) Statistically analyze the types (wind power, photovoltaic) and installed capacity of various new energy sources in the region, analyze the output data of typical new energy sources, including the power change rate and the maximum power change rate, and obtain the corresponding power change curve required for energy storage.

[0197] 2) Using the method of estimating the whole from the sample, the energy storage capacity configuration requirements of the new energy side in the whole region are estimated.

[0198] Generally, in order to suppress fluctuations in new energy output, improve the stability of new energy power generation, enhance power quality, promote the efficient consumption and utilization of new energy, and ensure the safe and stable operation of the system, energy storage on the power supply side should, in principle, be configured at 10% to 20% of the installed capacity of new energy.

[0199] (3) User-side energy storage capacity configuration method

[0200] User-side energy storage is typically configured for users with high reliability requirements, sensitivity to power quality, large peak-to-valley differences, and high demand-side response ratios. User power outages are probabilistic events, and user-side energy storage capacity requirements can be analyzed based on their expected values. Power supply reliability is derived from past outage experience. The expected power shortage for users due to each power outage is:

[0201] E ENS =T0(1-H s P0

[0202] In the formula: E ENS T0 represents the user's expected battery level; H represents the user's annual production hours; s P0 represents the power supply reliability; P0 represents the power required to ensure normal production for users.

[0203] The expected energy storage capacity can be determined based on the difference in outage rates before and after the energy storage system is put into operation.

[0204] E BESS =E ENS (λ s -λ0)

[0205] In the formula: E ENS λ represents the expected energy storage capacity. s λ0 represents the outage rate when no energy storage equipment is in use; λ0 represents the maximum allowable outage rate for load users.

[0206] In order to obtain the overall capacity configuration scheme of user-side energy storage in the region, an appropriate sample estimation method can be adopted to estimate the capacity configuration of user-side energy storage in the region.

[0207] Estimating the user load within a region by merely providing a quantitative estimate lacks practical reference value. Different types of users have different load characteristics and varying requirements for outage rates. Generally, industrial loads are relatively stable, commercial loads are more predictable, and residential loads fluctuate significantly. Therefore, the capacity configuration for user-side energy storage within a region can be implemented according to the following steps:

[0208] The method of estimating the user-side energy storage capacity configuration within the region using a sample estimation approach includes:

[0209] 1) Classify the user types within the region, and analyze their load characteristics based on the load curves of typical users in each category, including load peak, peak period, load trough, trough period, average load, and load peak-to-trough difference.

[0210] 2) Calculate the total electricity consumption of various user loads within the region and analyze the proportion of electricity consumption for each type of user load. Based on the importance of each type of user load, specify its power supply reliability requirements.

[0211] 3) The overall user-side energy storage capacity configuration demand is estimated using a sample estimation method. This involves estimating the load of different types of users separately and then summing the results to arrive at the overall energy storage capacity configuration demand.

[0212] Generally, for users who want to improve power quality, the energy storage capacity on the user side can be configured as needed based on the actual load scale and power quality requirements. For example, the energy storage capacity can be the product of the load exceeding 60% of the maximum load rate and the duration. For users who want to profit from peak-valley arbitrage, the energy storage capacity can generally be configured at about 10% to 20% of the maximum load, with a discharge time of 2 hours.

[0213] 4.7 Calculation Principles for the Standard Open Capacity of Distribution Network

[0214] 4.7.1 Data Requirements

[0215] (1) The calculation of the open capacity standard of the distribution network should be based on distributed power grid connection data, distributed power grid connection performance data, load data, energy storage data, grid equipment parameters, grid safe operation boundary data, etc., and should fully consider the power projects under construction and those that have been approved.

[0216] (2) The data should be derived from historical operating data, operating equipment parameters, actual power grid data, and construction planning data of power grid, new energy, and distributed power sources, and should fully consider factors such as geographical location, power grid structure, operating mode, load type, load level, and time scale.

[0217] 4.7.2 Data Preparation

[0218] (1) Distribution network data

[0219] Distribution network primary wiring diagram, distribution network geographical wiring diagram, 10kV line single-line diagram, power grid equivalent impedance diagram, short-circuit capacity table of each level of busbar, etc.

[0220] (2) Equipment data

[0221] 1) Distribution network equipment parameters and operating limits;

[0222] 2) Power supply characteristic data: power supply name, number of units, unit type, rated power of generator set, apparent power, installed capacity of unit, theoretical power generation, power factor adjustment range of unit, etc.

[0223] (3) Operational data

[0224] 1) Operation mode data: including data on the normal operation mode of the distribution network and power source.

[0225] 2) Distribution network operation data: Historical data on the output of various new energy sources and distributed power sources, grid load, bus voltage, etc. during the assessment period;

[0226] 3) Measured values ​​of harmonic current and interharmonic voltage content at each node of the power grid.

[0227] 4.7.3 Data Processing

[0228] (1) Calculate the power grid impedance parameters.

[0229] (2) Based on the actual installed capacity of new energy and distributed power sources in the distribution network, classify and organize power units of the same type and attribute in the same zone and perform equivalent calculations.

[0230] 4.8 Calculation Principles

[0231] 4.8.1 Maximum load rate of distribution network equipment

[0232] (1) The maximum load rate of the 10kV distribution transformer is 80%.

[0233] (2) The maximum load factor of the 10kV line is shown in Table 1 below.

[0234] Table 1. Maximum Load Rate Values ​​for 10kV Lines under Various Wiring Modes

[0235]

[0236] (3) The maximum load rate of the high-voltage substation is shown in Table 2 below.

[0237] Table 2. Values ​​of maximum load rate of substations under typical models.

[0238]

[0239] 4.8.2 Voltage Deviation

[0240] Distribution network planning must ensure that each node in the network meets the requirements for voltage loss and its distribution, and the voltage quality of power received by various users shall comply with the provisions of GB 12325.

[0241] (1) The sum of the absolute values ​​of the positive and negative deviations of the 110-35kV power supply voltage shall not exceed 10% of the nominal voltage.

[0242] (2) The allowable deviation of the three-phase power supply voltage of 10kV and below is ±7% of the nominal voltage.

[0243] (3) The allowable deviation of the 220V single-phase power supply voltage is +7% and -10% of the nominal voltage.

[0244] 4.8.3 Harmonic Current Allowable Values

[0245] The harmonic injection current at the point of common coupling (PCC) where distributed generation sources are connected shall meet the requirements of GB / T 14549 "Power Quality - Harmonics in Public Power Grids" and shall not exceed the allowable values ​​specified in the table below. The allowable harmonic current injected into the distribution network by distributed generation sources shall be allocated according to the ratio of the power source's protocol capacity to the capacity of the power generation / supply equipment at its PCC.

[0246] 4.8.4 Permissible short-circuit current value

[0247] The short-circuit capacity of each voltage level should be rationally controlled based on factors such as grid structure, voltage level, impedance selection, operating mode, and transformer capacity, so that the breaking current of circuit breakers at each voltage level matches the dynamic and thermal stability current of related equipment. The short-circuit current level of the busbars in the substation under normal operating conditions should generally not exceed the corresponding values ​​in the table below.

[0248] 4.9 Thermal stability limit load of 10kV line

[0249] Thermal stability, or rated short-time withstand current, is the effective value of the current that a switchgear or controlgear can withstand in the closed position for a specified period of time under specified operating and performance conditions. It is equal to the short-circuit rating of the switchgear or controlgear.

[0250] 4.10 Simulation Boundary Conditions for Maximum Distributed Power Generation Connection on a 10kV Line

[0251] Because medium-voltage lines carry a large number of loads, it is common for a single circuit to connect more than 30 distribution transformers. Therefore, load distribution becomes a significant factor affecting voltage. A basic load distribution model is as follows: Figure 2 The uniform load distribution curve is shown in the figure.

[0252] For each of the above basic load distribution models, a load distribution function is constructed, as shown in Table 3 below.

[0253] Table 3 Load distribution functions for each load distribution model

[0254]

[0255]

[0256] The overhead line conductor type is JKLYJ-240, the cable line conductor type is YJV22-3×300, the fixed bus voltage is 10.5kV, the substation power factor is 0.98, the photovoltaic power factor is 0.9, and four circuits are selected for simulation calculation. The main lengths of the four circuits are 3, 5, 10 and 15km respectively, and the lines are divided into three segments. Software simulation is carried out according to uniform load distribution, increasing distribution, decreasing distribution, convex distribution and concave distribution. The software used is the self-developed "Active Distribution Network Comprehensive Analysis System".

[0257] Example 2

[0258] The simulation calculations provided in this embodiment of the invention include:

[0259] (1) Simulation of maximum distributed photovoltaic access to 10kV distribution transformer

[0260] In the simulation of the maximum distributed photovoltaic system connected to a 10kV distribution transformer (400kVA, 1600kVA), such as... Figure 7 The simulation model diagram of the 400kVA distribution transformer is shown below; Figure 8 The simulation model diagram of the 1600VA distribution transformer is shown below.

[0261] In this embodiment of the invention, the maximum distributed photovoltaic capacity that a 400kVA distribution transformer can connect to is shown in Table 2 below.

[0262] Table 4 Simulation Results of Maximum Distributed Photovoltaic Capacity Connected to a 400kVA Distribution Transformer

[0263]

[0264]

[0265] The maximum distributed photovoltaic capacity that a 1600kVA distribution transformer can connect to is shown in Table 5 below.

[0266] Table 5 Simulation Results of Maximum Distributed Photovoltaic Capacity Connected to a 1600kVA Distribution Transformer

[0267]

[0268]

[0269] 2. Simulation of maximum distributed photovoltaic power transmission line access at 10kV speed

[0270] Simulation diagram of the maximum number of distributed photovoltaic lines connected to a 10kV line, as shown below. Figure 9 As shown, 01-15-1 represents the first segment of the 12km route; 01-15-2 represents the second segment of the 12km route; 01-15-3 represents the third segment of the 12km route; 02-10-1 represents the first segment of the 7km route; 03-5-1 represents the first segment of the 5km route; and 04-3-1 represents the first segment of the 3km route.

[0271] (1) Simulation results of uniform load distribution on 10kV lines

[0272] The maximum distributed photovoltaic capacity for 10kV line loads under uniform distribution conditions is shown in Table 6 below.

[0273] Table 6 Simulation Results of Maximum Distributed Photovoltaic Capacity under Uniform Load Distribution on 10kV Overhead Lines

[0274]

[0275]

[0276] Table 7. Simulation results of maximum distributed photovoltaic capacity under uniform load distribution on 10kV cable lines.

[0277]

[0278] (2) Simulation results of load reduction distribution on 10kV lines

[0279] The maximum distributed photovoltaic capacity for 10kV line load reduction is shown in Table 8 below.

[0280] Table 8. Simulation results of maximum distributed photovoltaic capacity under the load decreasing distribution of 10kV overhead lines.

[0281]

[0282]

[0283] Table 9 Simulation Results of Maximum Distributed Photovoltaic Capacity under Decreasing Load Distribution of 10kV Cable Lines

[0284]

[0285] (3) Simulation results of load increase distribution of 10kV line

[0286] The maximum distributed photovoltaic capacity for 10kV line load increase distribution is shown in Table 10 below.

[0287] Table 10 Simulation Results of Maximum Distributed Photovoltaic Capacity under Increasing Load Distribution of 10kV Overhead Lines

[0288]

[0289]

[0290] Table 11 Simulation Results of Maximum Distributed Photovoltaic Capacity under Increasing Load Distribution on 10kV Cable Lines

[0291]

[0292]

[0293] (4) Simulation results of convex load distribution on 10kV lines

[0294] The maximum distributed photovoltaic capacity for 10kV line loads under convex distribution conditions is shown in Table 11 below.

[0295] Table 11 Simulation Results of Maximum Distributed Photovoltaic Capacity under Convex Load Distribution of 10kV Overhead Lines

[0296]

[0297]

[0298] Table 12 Simulation Results of Maximum Distributed Photovoltaic Capacity under Convex Load Distribution on 10kV Cable Lines

[0299]

[0300]

[0301] (5) Simulation results of concave load distribution of 10kV line

[0302] The maximum distributed photovoltaic capacity for 10kV line loads under concave distribution conditions is shown in Table 13 below.

[0303] Table 13 Simulation Results of Maximum Distributed Photovoltaic Capacity under Concave Load Distribution of 10kV Overhead Lines

[0304]

[0305]

[0306] Table 14 Simulation Results of Maximum Distributed Photovoltaic Capacity under Concave Load Distribution of 10kV Cable Lines

[0307]

[0308] Simulation of maximum access capacity of high-voltage substation

[0309] Simulation diagram of the maximum number of distributed photovoltaic units connected to a high-voltage substation is shown below. Figure 11 As shown in Table 15, the maximum distributed photovoltaic capacity that can be connected to a high-voltage substation under different load rates is as follows.

[0310] Table 15 Simulation Results of Maximum Distributed Photovoltaic Capacity Connected to a 110kV High-Voltage Substation (2×50MVA)

[0311]

[0312]

[0313] 4. Typical calculation results of the openable capacity of distribution network equipment

[0314] Based on the above research findings, typical calculation results of the open capacity of distribution network equipment are shown in Tables 16-18 below.

[0315] Table 16 Calculation Results of Maximum Open Capacity of 10kV Distribution Transformer

[0316]

[0317] Table 17 Calculation Results of Maximum Open Capacity of 10kV Cable Lines

[0318]

[0319] Table 18 Calculation Results of Maximum Open Capacity of Main Transformer in High-Voltage Substation

[0320]

[0321]

[0322] Example 3

[0323] like Figure 10 As shown, an embodiment of the present invention provides a calculation and simulation system for the openable capacity standard of a distribution network, comprising:

[0324] Data acquisition module 1 is used to acquire data involved in the calculation of the open capacity standard of the distribution network; the data includes: historical operating data, operating equipment parameters, actual power grid data, construction planning data of the power grid and new energy sources and distributed power sources, geographical location, power grid structure, operating mode, load type, load level and time scale data;

[0325] The simulation boundary condition solidification module 2 is used to solidify the simulation boundary conditions related to the calculation of the open capacity standard of the distribution network. The boundary conditions include the maximum load rate of the distribution network equipment, voltage deviation, allowable value of harmonic current, allowable value of short-circuit current, line thermal stability limit load, and maximum number of distributed power sources connected to the line.

[0326] The scenario-specific simulation calculation module 3 is used to simulate the maximum access capacity of distribution transformers, lines, and substations in different scenarios to obtain the calculation results of the open capacity of distribution network equipment.

[0327] In the above embodiments, the descriptions of each embodiment have different focuses. For parts that are not described in detail or recorded in a certain embodiment, please refer to the relevant descriptions of other embodiments.

[0328] The information interaction and execution process between the above-mentioned devices / units are based on the same concept as the method embodiments of the present invention. For details on their specific functions and technical effects, please refer to the method embodiments section, and they will not be repeated here.

[0329] Those skilled in the art will understand that, for the sake of convenience and brevity, the above-described division of functional units and modules is merely an example. In practical applications, the functions described above can be assigned to different functional units and modules as needed, that is, the internal structure of the device can be divided into different functional units or modules to complete all or part of the functions described above. The functional units and modules in the embodiments can be integrated into one processing unit, or each unit can exist physically separately, or two or more units can be integrated into one unit. The integrated unit can be implemented in hardware or as a software functional unit. Furthermore, the specific names of the functional units and modules are only for easy differentiation and are not intended to limit the scope of protection of this invention. The specific working process of the units and modules in the above system can be referred to the corresponding process in the foregoing method embodiments, and will not be repeated here.

[0330] II. Application Examples:

[0331] Application Example 1: The method for calculating the open capacity of distribution network equipment based on a new power system provided in this embodiment of the invention can be applied to the distribution network of a demonstration zone and development zone in a certain province. In addition to the open capacity of the distribution system under normal circumstances, the active distribution network for the new power system also needs to consider the interruptible loads reduced by demand-side management, as well as the superposition of open capacity brought about by distributed power sources and energy storage access to the distribution system. The interruptible load is taken as 10% of the current maximum load of the area. Calculations show that the open capacity of the active distribution network of the new power system in the demonstration zone of a certain province is 60.53 MVA. The conventional open capacity of the distribution system in the demonstration zone is 33.53 MVA; the open capacity of the active distribution network of the new power system in the development zone of a certain province is 371.95 MVA.

[0332] Application Example 2: An embodiment of the present invention provides a computer device, which includes: at least one processor, a memory, and a computer program stored in the memory and executable on the at least one processor, wherein the processor executes the computer program to implement the steps in any of the above method embodiments.

[0333] Application Example 3: This embodiment of the invention also provides a computer-readable storage medium storing a computer program, which, when executed by a processor, can implement the steps in the above-described method embodiments.

[0334] Application Example 4: This embodiment of the invention also provides an information data processing terminal, which is used to provide a user input interface to implement the steps in the above method embodiments when executed on an electronic device. The information data processing terminal is not limited to mobile phones, computers, and switches.

[0335] Application Example 5: This embodiment of the invention also provides a server, which, when executed on an electronic device, provides a user input interface to implement the steps as described in the above method embodiments.

[0336] Application Example 6: This embodiment of the invention provides a computer program product that, when run on an electronic device, enables the electronic device to implement the steps in the above-described method embodiments.

[0337] If the integrated unit is implemented as a software functional unit and sold or used as an independent product, it can be stored in a computer-readable storage medium. Based on this understanding, all or part of the processes in the methods of the above embodiments of the present invention can be implemented by a computer program instructing related hardware. The computer program can be stored in a computer-readable storage medium, and when executed by a processor, it can implement the steps of the various method embodiments described above. The computer program includes computer program code, which can be in the form of source code, object code, executable files, or certain intermediate forms. The computer-readable medium can include at least: any entity or device capable of carrying the computer program code to a photographing device / terminal device, a recording medium, a computer memory, a read-only memory (ROM), a random access memory (RAM), an electrical carrier signal, a telecommunication signal, and a software distribution medium. Examples include USB flash drives, portable hard drives, magnetic disks, or optical disks.

[0338] III. Evidence of the relevant effects of the embodiments:

[0339] This invention systematically analyzes the influencing factors of the open capacity of the distribution network. The influencing factors of the open capacity of the distribution network are divided into four aspects: safety and reliability, clean and low carbon, flexibility and efficiency, and open interaction through the analytic hierarchy process. The specific influencing factors of each aspect are analyzed through the fishbone diagram analysis method, and a system of influencing factors of the open capacity of the distribution network is constructed.

[0340] This invention also selected a demonstration zone and a development zone in a certain province as typical areas to conduct empirical applications of the research results, verifying the scientific validity, effectiveness, and practicality of the findings. This invention solidifies the calculation process for the open capacity of distribution networks, establishes annual evaluation of the open capacity of distribution networks as a necessary and routine task, and establishes a refined planning and management concept. Based on the calculation methods and standard calculation principles for the open capacity of distribution systems, the evaluation of the open capacity of distribution network equipment and active distribution systems oriented towards new power systems is established as a necessary and routine task. This refines the research results, accumulates implementation experience, better serves the planning, operation, and maintenance management of new distribution systems, and precisely improves the safety, reliability, and economy of existing distribution network construction.

[0341] The application results of this invention include the development of intelligent calculation software for the available capacity of distribution networks. This software enables rapid viewing of distribution network access resources and available capacity information, significantly reducing manual intervention steps and time. Similarly, the software promptly calculates and updates the available capacity of corresponding lines and main transformers for incoming business expansion applications, preventing excessive business expansion requests from being accepted on the same line at the same time. This invention actively takes measures to improve the distribution network's ability to accommodate new energy sources, distributed power sources, and diversified loads.

[0342] 1) Serving distributed power generation grid connection. Promoting the application of technologies such as new energy power generation prediction systems and "plug-and-play" grid connection equipment for distributed power generation to meet the requirements of widespread access for new energy and distributed power generation; orderly constructing demonstration projects such as new distribution systems and distributed multi-energy complementarity to improve the coordination capability between distributed power generation and distribution network.

[0343] 2) Implement a user-friendly smart and interactive project. Using smart meters as the carrier, build a smart metering system and create a smart service platform to fully support user information interaction, distributed power source access, electric vehicle charging and discharging, electric heating and other services, encourage users to participate in power grid peak shaving and valley filling, and improve the overall carrying capacity of the distribution network.

[0344] 3) By applying advanced power distribution technology, scientifically selecting conductor cross-sections and transformer specifications, improving the level of economic operation, strengthening the reactive power planning and operation management of the power distribution network, achieving local reactive power balance at each voltage level, reducing power transmission losses, and scientifically and efficiently improving the open capacity of the power distribution network.

[0345] The above description is only a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any modifications, equivalent substitutions and improvements made by those skilled in the art within the scope of the technology disclosed in the present invention and within the spirit and principles of the present invention should be covered within the scope of protection of the present invention.

Claims

1. A method for calculating and simulating the standard open capacity of a distribution network, characterized in that, The method includes the following steps: S1, obtain the data involved in the calculation of the open capacity standard of the distribution network; The data includes: historical operating data, operating equipment parameters, power grid measured data, power grid and new energy data, distributed power generation construction planning data, geographical location data, power grid structure data, operating mode data, load type data, load level data, and time scale data. S2, Fixed boundary conditions for calculation and simulation of open capacity standards of distribution network; Boundary conditions include: maximum load rate of distribution network equipment, voltage deviation, allowable harmonic current, allowable short-circuit current, line thermal stability limit load, and maximum number of distributed power sources connected to the line; S3 simulates the maximum access capacity of lines, distribution transformers, substations, and different scenarios to obtain the calculation results of the open capacity of distribution network equipment. Step S3, simulating the maximum access capacity of the line, includes: Based on the uniform load distribution model, decreasing load distribution model, increasing load distribution model, increasing-then-decreasing load distribution model, and decreasing-then-increasing load distribution model, the load distribution functions of each load distribution model are constructed sequentially: ； ； ； ； ； It is the distance from the beginning of the line Three-phase power at the load point, i.e., three-phase load density, is measured in units of... P represents the three-phase active power transmitted at the beginning of the line, measured in units of... ; It is the distance from the beginning of the line, in units of ; It is the total length of the line, in units of .

2. The method for calculating and simulating the standard open capacity of a distribution network according to claim 1, characterized in that, Step S3, simulating the maximum connected capacity of the distribution transformer, includes: Distributed photovoltaic capacity ratio = Distributed photovoltaic capacity / 10kV distribution transformer capacity × 100%.

3. The method for calculating and simulating the standard open capacity of a distribution network according to claim 1, characterized in that, Step S3, simulating the maximum access capacity of the substation, includes: Grid-side energy storage capacity configuration: By reducing the substation load rate and peak shaving and valley filling to reduce the peak-valley difference rate of the grid load, the energy storage capacity configuration for substation load reduction and peak shaving and valley filling is implemented. Energy storage capacity configuration on the power supply side: The energy storage capacity configuration on the new energy side in the region is estimated by using a sample estimation method to estimate the overall capacity. User-side energy storage capacity configuration: The user-side energy storage capacity configuration in the region is estimated using a sample estimation method.

4. The method for calculating and simulating the standard open capacity of a distribution network according to claim 3, characterized in that, Reducing the substation load factor includes: The power requirement for configuring energy storage devices is calculated using the following formula: ； In the formula, Select the power configuration value for energy storage. This represents the real-time load power value. This refers to the heavy-load power threshold of the substation. The power level of the critical load is given; based on the above-mentioned energy storage configuration power selection values, the formula for calculating the configured energy storage capacity is as follows: ； In the formula, Select a value for the configured energy storage capacity. Select the power configuration value for energy storage. This refers to the overload time of the substation. The operating cycle of critical loads; Peak shaving and valley filling include: the energy storage power is taken as the maximum limit of the power grid's peak shaving capacity, and the calculation formula for the energy storage power is as follows: ； In the formula, The power selection value for the energy storage system. Let i be the output demand value of the energy storage system calculated at each time point, where i = 1, 2, ..., N; based on the above power selection values ​​of the energy storage system, the energy storage capacity selection formula is: ； ； ； In the formula: Select the energy storage capacity value for the energy storage system; The data sampling time interval is 1 to m1, m2 to m3, ..., m j ~m n This refers to the time period during which the energy storage is in a charging and discharging state.

5. The method for calculating and simulating the standard open capacity of a distribution network according to claim 4, characterized in that, The energy storage capacity configuration on the power supply side is as follows: Based on the power output data of new energy sources and the requirements of the rate of change of grid-connected active power, the energy storage power variation range curve is obtained: ； In the formula: For energy storage Output power of each sample; To smooth out the maximum power fluctuation value in the first 10 minutes; The maximum allowable change in the power input to the grid from new energy sources within 10 minutes; Energy storage demand power follows a normal distribution, which is derived from the normal distribution 3 The formula for calculating energy storage power is as follows: ； ； ； In the formula, Select a value for energy storage capacity. This represents the average energy storage capacity. For the sample size, , These are the mean and standard deviation of the sample data, respectively. Utilizing the above energy storage power Multiply by the number of hours of continuous energy storage output The formula for calculating energy storage capacity is as follows: ， The calculation of energy storage capacity configuration for new energy sources within the region is based on the large number of new energy sources within the region. The method of estimating the overall energy storage capacity configuration of new energy sources in the region is adopted, specifically including: 1) Statistically analyze the types and installed capacity of various new energy sources in the region, analyze the output data of typical new energy sources, including the power change rate and the maximum power change rate, and obtain the corresponding power change curve required for energy storage; 2) Using the method of estimating the whole from the sample, the energy storage capacity configuration requirements of the new energy side in the entire region are estimated.

6. The method for calculating and simulating the standard open capacity of a distribution network according to claim 3, characterized in that, In the configuration of user-side energy storage capacity, the expected value of the power shortage caused to users by each power outage is: ； In the formula, This is the user's expected value when the battery is low. For users' annual production hours, For power supply reliability, To ensure the power required for normal production by users; The expected energy storage capacity is determined based on the difference in outage rates before and after the energy storage system is put into operation. ； In the formula: This represents the expected energy storage capacity. The outage rate when no energy storage equipment is in use; The maximum allowable power outage rate for load users; The method of estimating the user-side energy storage capacity configuration within the region using a sample estimation approach includes: 1) Classify the user types within the region, and analyze their load characteristics based on the load curves of typical users in each category, including load peak, peak period, load trough, trough period, average load, and load peak-to-trough difference; 2) Calculate the total electricity consumption of various user loads within the region and analyze the proportion of electricity consumption for each type of user load; 3) The overall energy storage capacity configuration requirement of the entire region is estimated by using the sample estimation method; the load of different types of users is estimated separately and then superimposed to form the overall energy storage capacity configuration.

7. A system for implementing the calculation and simulation method for the openable capacity standard of a distribution network according to any one of claims 1-6, characterized in that, The open capacity standard calculation and simulation system for this power distribution network includes: The data acquisition module (1) is used to acquire the data involved in the calculation of the open capacity standard of the distribution network; the data includes: historical operation data, operating equipment parameters, actual power grid data, construction planning data of power grid and new energy, distributed power sources, geographical location, power grid structure, operation mode, load type, load level and time scale data; The simulation boundary condition solidification module (2) is used to solidify the simulation boundary conditions related to the calculation of the open capacity standard of the distribution network. The boundary conditions include the maximum load rate of the distribution network equipment, voltage deviation, allowable value of harmonic current, allowable value of short-circuit current, line thermal stability limit load and the maximum number of distributed power sources connected to the line. The scenario-based simulation calculation module (3) is used to simulate the maximum access capacity of distribution transformers, lines and substations in different scenarios to obtain the calculation results of the open capacity of distribution network equipment.

8. A computer device, characterized in that, The computer device includes a memory and a processor. The memory stores a computer program. When the computer program is executed by the processor, the processor performs the calculation and simulation method for the openable capacity standard of the distribution network as described in any one of claims 1-6.

9. A computer-readable storage medium storing a computer program, characterized in that, When the computer program is executed by the processor, the processor performs the calculation and simulation method for the openable capacity standard of the distribution network as described in any one of claims 1-6.

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