Rural power grid capacity planning method and system considering overload risk

Abstract

The invention is suitable for the technical field of capacity planning, and provides a rural power grid capacity planning method and system considering overload risk, and the method comprises the steps: collecting and analyzing the historical load data of a regional power grid, and respectively calculating the capacity limits of photovoltaic access in a single-radiation power supply mode and a hand-in-hand power supply mode; constructing a target function of a rural power grid capacity planning model by taking reduction of power grid vulnerability and reduction of active power loss as target parameters; determining constraint conditions of the rural power grid capacity planning model, wherein the constraint conditions comprise a power balance constraint and a voltage constraint; a target rural power grid capacity planning scheme is determined by planning the photovoltaic installed capacity of each load point in a single-radiation power supply mode and a hand-in-hand power supply mode, so that the consumption capacity of photovoltaic energy can be mastered, the reasonable grid-connected layout of photovoltaic power generation can be promoted, and the operation efficiency and reliability of a power grid are improved.

Description

Technical Field

[0001] The present invention relates to the technical field of capacity planning, and in particular to a rural power grid capacity planning method and system taking into account overload risks. Background Art

[0002] The increase of photovoltaic power sources makes the electrical characteristics of the power grid more complex and changeable, and puts forward higher requirements for power supply quality and stability. At present, for rural power grid capacity planning, some studies have proposed a distributed power supply capacity calculation model that takes into account short-circuit current constraints, but this model is difficult to ensure the reliable operation of relay protection under various circumstances. Therefore, the single radiation power supply mode and the hand-in-hand power supply mode can be used, but the overload risk in these two modes is a hard limit for the access of distributed power sources. Failure to consider the overload risk may cause the transmission capacity of the equipment or line to exceed the carrying capacity, triggering the overload protection action, causing the equipment or line to exit the power grid, and reducing the reliability of load power supply.

[0003] In view of this, a rural power grid capacity planning method and system that takes overload risk into consideration is needed. Summary of the invention

[0004] The embodiments of the present application provide a rural power grid capacity planning method and system taking into account overload risks, which are used to solve the problem of reducing system load power supply.

[0005] A first aspect of an embodiment of the present application provides a rural power grid capacity planning method considering overload risk, including:

[0006] Collect and analyze historical load data of the regional power grid, and calculate the capacity limit of photovoltaic access in the single radiation power supply mode and the hand-in-hand power supply mode;

[0007] The objective function of the rural power grid capacity planning model is constructed with reducing grid vulnerability and active power loss as target parameters;

[0008] Determining constraints of a rural power grid capacity planning model, wherein the constraints include power balance constraints and voltage constraints;

[0009] The target rural power grid capacity planning scheme is determined by planning the photovoltaic installed capacity of each load point under the single radiation power supply mode and the hand-in-hand power supply mode.

[0010] Furthermore, the collection and analysis of historical load data of the regional power grid and the calculation of the capacity limit of photovoltaic access in the single radiation power supply mode and the hand-in-hand power supply mode respectively include:

[0011] The calculation formula for the photovoltaic access capacity limit under the single radiation power supply mode is:

[0012]

[0013] S max con,max

[0014] Where: S con,max is the maximum apparent power, and is the maximum active power and maximum reactive power, S max is the maximum power flow after connecting to the distributed photovoltaic power source, P con,mid and They are the minimum load active and reactive power and the minimum load reactive power respectively.

[0015] Furthermore, the collection and analysis of historical load data of the regional power grid and the calculation of the capacity limit of photovoltaic access in the single radiation power supply mode and the hand-in-hand power supply mode respectively include:

[0016] The calculation formula for the capacity limit of photovoltaic access in the hand-in-hand power supply mode is:

[0017]

[0018] Where: P gen1,max and P con1,min are the maximum power generation of the photovoltaic power sources connected to feeder 1 and feeder 2, respectively. and are the maximum apparent power of the loads on feeder 1 and feeder 2, respectively, P com1,min and P com2,min are the active powers corresponding to the minimum loads on feeder 1 and feeder 2, respectively. and are the reactive powers corresponding to the minimum loads on feeder 1 and feeder 2, respectively, (P gen1 +P gen2 ) max is the maximum total power of the photovoltaic power sources connected to the two feeders, is the maximum apparent power of the total load of the two feeders, is the total reactive power corresponding to the minimum load of the two feeders, (P con1 +P con2 ) min is the total active power corresponding to the minimum load of the two feeders.

[0019] Furthermore, the objective function of the rural power grid capacity planning model constructed with reducing power grid vulnerability and reducing active power loss as target parameters includes:

[0020] The expression of the objective function with reducing grid vulnerability as the target parameter is:

[0021] f 1 =λ 1 BV(t)+λ​2 J(t)

[0022]

[0023] Where: BV(t) is the average vulnerability of the power grid, J(t) is the equilibrium degree of vulnerability distribution of each node in the network, J(t)∈[0,1], from 0 to l from absolute imbalance to absolute balance, λ 1 and λ 2 are the corresponding weight coefficients, N is the number of nodes, V(t,i) is the voltage value of node i at time t, p t,i is the probability of an event affecting grid vulnerability occurring at node i at time t.

[0024] Furthermore, the objective function of the rural power grid capacity planning model constructed with reducing power grid vulnerability and reducing active power loss as target parameters includes:

[0025] The expression of the objective function with reducing active power loss as the target parameter is:

[0026]

[0027] Where: M L For all branches, G ij is the conductance of nodes i and j, U i,t and U j,t are the voltages of nodes i and j at time t, δ ij,t is the phase angle difference between nodes i and j at time t.

[0028] Furthermore, the constraint conditions of the rural power grid capacity planning model are determined, and the constraint conditions include power balance constraint and voltage constraint, including:

[0029] Power balance constraints:

[0030]

[0031] Where: N DG and N sre are the number of distributed power and energy storage devices, respectively, DG,i (t) is the active power of the ith DG at time t, p store,j (t) is the charge and discharge power of the jth energy storage device at time t, p loαl (t) and P LOSS,j (t) is the system load and active network loss at time t;

[0032] Voltage Constraints:

[0033]

[0034] in: and are the lower and upper voltage limits of node i, V i is the voltage at node i.

[0035] Furthermore, the target rural power grid capacity planning scheme is determined by planning the photovoltaic installed capacity of each load point under the single radiation power supply mode and the hand-in-hand power supply mode, including:

[0036] Based on the single radiation power supply mode, key parameters are extracted by collecting historical load data of the regional power grid; at the same time, the maximum allowable photovoltaic installation capacity of each load point is determined;

[0037] Based on the hand-in-hand power supply mode, the historical load data of the single section and the entire feeder area are collected and relevant parameters are extracted. The maximum photovoltaic installation capacity of each load point is determined by calculating and comparing the photovoltaic power generation capacity of each area.

[0038] A second aspect of an embodiment of the present application provides a rural power grid capacity planning system considering overload risks, including:

[0039] The capacity limit calculation unit is used to collect and analyze the historical load data of the regional power grid, and calculate the capacity limit of photovoltaic access in the single radiation power supply mode and the hand-in-hand power supply mode respectively;

[0040] An objective function building unit is used to build an objective function of a rural power grid capacity planning model with reducing power grid vulnerability and reducing active power loss as target parameters;

[0041] A constraint determination unit, used to determine the constraint of the rural power grid capacity planning model, wherein the constraint includes a power balance constraint and a voltage constraint;

[0042] The target rural power grid capacity planning scheme determination unit is used to determine the target rural power grid capacity planning scheme by planning the photovoltaic installed capacity of each load point under the single radiation power supply mode and the hand-in-hand power supply mode.

[0043] A third aspect of the embodiments of the present application provides a computer device, including:

[0044] memories, transceivers, processors, and bus systems;

[0045] Wherein, the memory is used to store programs;

[0046] The processor is used to execute the program in the memory, including executing the rural power grid capacity planning method considering overload risk as described in any one of the above;

[0047] The bus system is used to connect the memory and the processor so that the memory and the processor can communicate with each other.

[0048] A fourth aspect of an embodiment of the present application provides a readable storage medium, including instructions, which, when executed on a computer, enables the computer to execute the steps of the rural power grid capacity planning method considering overload risks as described in any one of the above.

[0049] It can be seen from the above technical solutions that the embodiments of the present invention have the following advantages:

[0050] The present invention collects and analyzes the historical load data of the regional power grid, calculates the capacity limit of photovoltaic access under the single radiation power supply mode and the hand-in-hand power supply mode respectively, and takes the overload risk as the key factor limiting the photovoltaic access capacity; constructs a model with the goal of reducing the vulnerability of the power grid, and combines conditions such as power balance and voltage constraints to enhance the ability of the power grid to resist risks, reduce the instability of the power grid caused by photovoltaic access or other factors, reduce the planning of active power loss, reduce the energy loss of the power grid during transmission and distribution, and improve energy utilization efficiency; conducts preliminary planning of the maximum photovoltaic access capacity of the rural power grid, which not only helps to grasp the consumption capacity of photovoltaic energy, but also promotes the reasonable grid-connected layout of photovoltaic power generation, thereby improving the operation efficiency and reliability of the power grid. BRIEF DESCRIPTION OF THE DRAWINGS

[0051] Figure 1 A schematic diagram of an embodiment of a method for planning rural power grid capacity taking into account overload risk in the present invention;

[0052] Figure 2 It is a schematic diagram of the structure of a single radiation power supply in the present invention;

[0053] Figure 3 This is a schematic diagram of the hand-in-hand power supply structure in the present invention;

[0054] Figure 4 This is a schematic diagram of the 10kV hand-in-hand power supply structure of a village in the present invention. DETAILED DESCRIPTION

[0055] The terms "first", "second", "third", "fourth", etc. (if any) in the specification and claims of the present invention and the above-mentioned drawings are used to distinguish similar objects, and are not necessarily used to describe a specific order or sequence. It should be understood that the data used in this way can be interchangeable where appropriate, so that the embodiments of the present application described herein can be implemented in an order other than those illustrated or described herein, for example. In addition, the terms "including" and "corresponding to" and any variations thereof are intended to cover non-exclusive inclusions, for example, a process, method, system, product or device that includes a series of steps or units is not necessarily limited to those steps or units that are clearly listed, but may include other steps or units that are not clearly listed or inherent to these processes, methods, products or devices.

[0056] Embodiment 1

[0057] The implementation method in this embodiment can be implemented in the system, can be implemented in the server, and can also be implemented in the terminal, and the specific details are not clearly limited. The following will introduce the rural power grid capacity planning method considering overload risk in the present invention from the perspective of system implementation. Figure 1 , the method provided in the embodiment of the present application comprises the following steps:

[0058] S11. Collect and analyze the historical load data of the regional power grid, and calculate the capacity limit of photovoltaic access in the single radiation power supply mode and the hand-in-hand power supply mode respectively;

[0059] Collecting historical load data of regional power grids includes obtaining data from the power company's operation database, energy management system or related monitoring equipment, which records the operation status of the regional power grid in the past period of time. The data includes time series load data and special working condition data, such as load information such as active power, reactive power, and apparent power at different times, reflecting the change pattern of power grid load over time, such as load fluctuations in 24 hours a day and different seasons of the year, such as load data under special circumstances such as holidays and extreme weather.

[0060] Clean the collected data to remove abnormal values, missing values ​​and other erroneous data. Interpolation and mean methods can be used to fill missing values. Statistical analysis can be used to identify and correct abnormal values. Analyze the daily load curve to find out the peak and valley load periods and the corresponding load amounts, and determine the load change trend within a day; analyze seasonal load patterns such as load changes in different months and seasons; analyze the correlation between loads at different nodes and lines, and determine the mutual influence of load changes.

[0061] 1. Take the common single radial structure of rural power grid as an example, Figure 2 As shown, the entire radial regional distribution network is equivalent to the overall load. It is assumed that the equipment and lines are not overloaded before the introduction of distributed photovoltaic power generation, and the load active and reactive power demands are synchronized with time.

[0062] Assume that the total apparent power in the area is S con , where active power and reactive power are P con and Q con At the same time, assuming that the photovoltaic power generation in the area is P gen , ignoring the transmission loss of photovoltaic power generation, the current from a single power source to the regional power grid is:

[0063]

[0064] Before the introduction of distributed photovoltaic power generation, equipment and lines are usually not overloaded. At this time, the maximum power flow occurs at the maximum load, and the maximum apparent power can be expressed as:

[0065]

[0066] It is assumed that the load active and reactive power demands are synchronized with time, that is, when the active power reaches its maximum value, the reactive power also reaches its maximum value at the same time.

[0067] When a large number of distributed photovoltaic power generation units are connected to the regional distribution network, photovoltaic power generation is a reverse flow. When the photovoltaic output is the largest, the reverse flow reaches its maximum value. Photovoltaic power generation generally reaches its maximum value at noon (11:00-14:00). Assume that the minimum active and reactive values ​​of the load corresponding to noon are S con,max and Q con,mid The maximum power flow after connecting to the distributed photovoltaic power source is:

[0068]

[0069] When the distributed photovoltaic power source is connected, as long as the maximum flow after connection is less than the maximum flow before connection, there will be no overload, that is, it should meet the following conditions:

[0070] S max con,max

[0071] In the above formula: S con,max is the maximum apparent power, and is the maximum active power and maximum reactive power, S max is the maximum power flow after connecting to the distributed photovoltaic power source, P con,mid and They are the minimum load active and reactive power and the minimum load reactive power respectively.

[0072] The above formula can be derived:

[0073]

[0074] Where: P con,min and are respectively the active power and reactive power under the minimum load in the area. This is the maximum power generation allowed by photovoltaics under the single radiation power supply mode, that is, the access capacity limit.

[0075] 2. The hand-in-hand power supply mode is a common power supply mode in rural areas, such as Figure 3 As shown in the figure, taking two feeders as an example, it is a dual power supply ring network structure but operates in a radial structure. The dual feeders are mutually redundant, and the load power supply reliability is improved through the tie switch. To prevent the two feeders from overloading after connecting to the photovoltaic power source, the following conditions must be met:​

[0076]

[0077] In standby mode, the loads of the two feeders are powered by the same power source, so the PV power and load are the sum of the two feeders. To ensure that there is no overload during standby, the maximum power of the total power of the two feeders also needs to be met:

[0078]

[0079] In the above formula: P gen1,max and P con1,min are the maximum power generation of the photovoltaic power sources connected to feeder 1 and feeder 2, respectively. and are the maximum apparent power of the loads on feeder 1 and feeder 2, respectively, P con1,min and P con2,min are the active powers corresponding to the minimum loads on feeder 1 and feeder 2, respectively. and are the reactive powers corresponding to the minimum loads on feeder 1 and feeder 2, respectively, (P gen1 +P gen2 ) max is the maximum total power of the photovoltaic power sources connected to the two feeders, is the maximum apparent power of the total load of the two feeders, is the total reactive power corresponding to the minimum load of the two feeders, (P con1 +P con2 ) min is the total active power corresponding to the minimum load of the two feeders.

[0080] By simultaneously meeting the conditions in normal operation and standby mode, the photovoltaic access capacity limit in the hand-in-hand power supply mode is determined.

[0081] S12. Construct the objective function of the rural power grid capacity planning model with reducing power grid vulnerability and reducing active power loss as target parameters;

[0082] S13. Determine the constraints of the rural power grid capacity planning model, the constraints including power balance constraints and voltage constraints;

[0083] Specifically, grid vulnerability refers to the possibility that the grid loses its stable operating state when facing various internal and external interferences. Reducing grid vulnerability can improve the reliability and risk resistance of the grid and ensure the stable supply of electricity in rural areas. Active power loss refers to the power lost during the transmission and distribution of electricity in the grid due to factors such as line resistance and transformer loss. Reducing active power loss can improve energy utilization efficiency, reduce grid operation costs and demand for power generation resources.

[0084] Specifically, the expression of the objective function with reducing grid vulnerability as the target parameter is:

[0085] f 1 =λ 1 BV(t)+λ 2 J(t)

[0086]

[0087] Where: BV(t) is the average vulnerability of the power grid, J(t) is the equilibrium degree of vulnerability distribution of each node in the network, J(t)∈[0,1], from 0 to l from absolute imbalance to absolute balance, λ 1 and λ 2 are the corresponding weight coefficients, N is the number of nodes, V(t,i) is the voltage value of node i at time t, p t,i is the probability of an event affecting grid vulnerability occurring at node i at time t.

[0088] The expression of the objective function with reducing active power loss as the target parameter is:

[0089]

[0090] Where: M L For all branches, G ij is the conductance of nodes i and j, U i,t and U j,t are the voltages of nodes i and j at time t, δ ij,t is the phase angle difference between nodes i and j at time t.

[0091] The constraints include power balance constraints and voltage constraints. The specific expressions are as follows:

[0092] Power balance constraints:

[0093]

[0094] Where: N DG and N sre are the number of distributed power and energy storage devices, respectively, DG,i (t) is the active power of the ith DG at time t, p store,j (t) is the charge and discharge power of the jth energy storage device at time t, p loαl (t) and P LOSS,j (t) is the system load and active network loss at time t;

[0095] Voltage Constraints:

[0096]

[0097] in: and are the lower and upper voltage limits of node i, V i is the voltage at node i.

[0098] S14. Determine the target rural power grid capacity planning scheme by planning the photovoltaic installed capacity of each load point under the single radial power supply mode and the hand-in-hand power supply mode.

[0099] Planning of photovoltaic installed capacity at load points under single radiation power supply mode:

[0100] Obtain typical historical load data of regional power grids from power companies, energy monitoring agencies, etc., covering a long period of time, including load information of different seasons and date types, accurate to specific time points, such as recording active power, reactive power, apparent power and other data every 15 minutes or 30 minutes. Extracting the maximum apparent power of the regional power grid at different time periods based on historical load data can reflect the power carrying demand of the power grid in the busiest state; determining the minimum active power can reflect the active demand level of the power grid when the load is low; obtaining the minimum reactive power can evaluate the reactive balance of the power grid and maintain voltage stability.

[0101] Based on a variety of factors that affect the power generation efficiency of photovoltaic systems, such as the conversion efficiency of photovoltaic panels, installation angle, weather conditions, and seasonal changes, combined with photovoltaic power generation efficiency and grid load demand, the maximum power generation capacity of the photovoltaic system under ideal conditions is calculated. Considering factors such as the installation capacity of photovoltaic panels and the average local sunshine duration, the maximum power output that the photovoltaic system can generate at different times is estimated. Based on the maximum power generation capacity of the photovoltaic system and the load characteristics of the grid, the maximum allowable photovoltaic installation capacity of each load point is determined. After photovoltaic access, it is ensured that the grid can remain stable under various operating conditions without problems such as overload and voltage limit. For example, when photovoltaic power generation is large, the grid can safely absorb excess electricity; when photovoltaic power generation is insufficient, the grid can also meet the load demand.

[0102] Planning of photovoltaic installed capacity at load points under the hand-in-hand power supply mode:

[0103] Collect typical historical load data for each section of the feeder area in the hand-in-hand power supply mode, including power data of each load point in the area and transmission parameters of the feeder. Extract the maximum apparent power and minimum active power of the single section feeder area from the collected data. Calculate the maximum photovoltaic power generation capacity allowed for each section of the feeder area based on the extracted parameters, photovoltaic panel installation capacity, local sunshine conditions, seasonal changes and other factors. Ensure that after photovoltaic access, the single section feeder can operate safely and stably under normal operation and fault conditions.

[0104] Collect typical historical load data of the entire feeder area, including the sum of all single-section feeder areas, as well as information such as the connection relationship and transmission characteristics between feeders. Extract three total load parameters from the historical load data, including the maximum apparent power of the total load of the two feeders, the total reactive power corresponding to the minimum load, and the total active power corresponding to the minimum load. Based on the total load parameters of the entire feeder area, consider the photovoltaic power generation potential of all single-section feeder areas and calculate the maximum power generated by the entire photovoltaic power supply. Evaluate the power supply capacity of the photovoltaic power supply to the entire feeder area under different operating modes.

[0105] Compare the PV power generation capacity of the entire feeder area with the maximum PV power generation capacity allowed in a single-section feeder area. If the overall capacity exceeds the single-section limit, it may cause feeder overload or other operating problems, and adjustments need to be made. If adjustments are required, ensure that the PV power generation capacity of the entire feeder area does not exceed the maximum power generation capacity limit of the single-section feeder area by reallocating the installation location of the PV panels, adjusting the number of installations, or optimizing the operating strategy of the PV system.

[0106] The following is a detailed description with specific examples:

[0107] Take the 10kV hand-in-hand power supply structure of a village distribution network as an example. Figure 4 As shown in the figure, the interconnected power grid contains two feeders, of which feeder 1 has 3 load points and feeder 2 has 2 load points. The flow data from the power supply side to the single-stage feeder in the past year were collected, that is, the flow data at points A1 and A2 in the figure. The maximum and minimum power parameters of the load in the single-section feeder area were obtained by statistics. At the same time, the power data at points A1 and A2 were superimposed to obtain the load current data of the total feeder in the past year, and the maximum and minimum power parameters of the total feeder load were obtained by statistics. The load parameters are shown in Table 1:

[0108] Table 1

[0109]

[0110] According to the load parameters shown in Table 1, the maximum power generation allowed by the photovoltaic power source on feeder 1 and feeder 2 can be calculated as:

[0111] P gen1,max <12.06MW

[0112] P gen2,max <8.46MW

[0113] In standby mode, the maximum power generated by the total photovoltaic power source must be met:

[0114] P gen1,max +P gen2,max <19.8MW

[0115] Since the above formula conditions need to be met, the maximum power generation of the photovoltaic power source allowed on feeder 1 and feeder 2 can be adjusted. The maximum power generation of feeder 1 and feeder 2 is planned to be 12MW and 7.8MW respectively. Considering that the actual power generation efficiency of the photovoltaic power source is calculated as 80%, the maximum installed capacity of photovoltaic power connected to feeder 1 and feeder 2 is allowed to be 15MW and 9.75MW respectively.

[0116] It can be seen that by planning the photovoltaic installed capacity of each load point under the single radiation power supply mode and the hand-in-hand power supply mode, combining the load characteristics, operation mode and characteristics of photovoltaic power generation of the power grid, the rationality and feasibility of the target rural power grid capacity planning scheme are generated, which can realize the rational and efficient acceptance of photovoltaic energy by the rural power grid.

[0117] Embodiment 2

[0118] An embodiment of a rural power grid capacity planning system considering overload risk in the present invention comprises the following steps:

[0119] The capacity limit calculation unit is used to collect and analyze the historical load data of the regional power grid, and calculate the capacity limit of photovoltaic access in the single radiation power supply mode and the hand-in-hand power supply mode respectively;

[0120] An objective function building unit is used to build an objective function of a rural power grid capacity planning model with reducing power grid vulnerability and reducing active power loss as target parameters;

[0121] A constraint determination unit, used to determine the constraint conditions of the rural power grid capacity planning model, the constraint conditions including power balance constraint and voltage constraint;

[0122] The target rural power grid capacity planning scheme determination unit is used to determine the target rural power grid capacity planning scheme by planning the photovoltaic installed capacity of each load point under the single radiation power supply mode and the hand-in-hand power supply mode.

[0123] Embodiment 3

[0124] The present invention provides a computer device, comprising a memory, a processor, and computer-readable instructions stored in the memory and executable on the processor. When the processor executes the computer-readable instructions, the steps of the above method are implemented.

[0125] Those of ordinary skill in the art will appreciate that the units of each example described in conjunction with the embodiments disclosed herein can be implemented in electronic hardware, computer software, or a combination of the two. In order to clearly illustrate the interchangeability of hardware and software, the composition of each example has been generally described in terms of function in the above description. Whether these functions are performed in hardware or software depends on the specific application and design constraints of the technical solution. Professional and technical personnel can use different methods to implement the described functions for each specific application, but such implementation should not be considered to be beyond the scope of the present invention.

[0126] In the embodiments provided by the present invention, it should be understood that the division of units is only a logical function division, and there may be other division methods in actual implementation, such as multiple units can be combined into one unit, one unit can be split into multiple units, or some features can be ignored. In addition, each functional unit in each embodiment of the present invention can be integrated into a processing unit, or each unit can exist physically separately, or two or more units can be integrated into one unit. The above-mentioned integrated unit can be implemented in the form of hardware or in the form of software functional units.

[0127] If the integrated unit is implemented in the form of 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, the technical solution of the present invention, in essence, or the part that contributes to the prior art, or all or part of the technical solution can be embodied in the form of a software product, which is stored in a storage medium and includes several instructions for a computer device (which can be a personal computer, a server or a network device, etc.) to perform all or part of the steps of the method described in each embodiment of the present invention. The aforementioned storage medium includes: U disk, read-only memory (ROM, Read-0nlyMemory), random access memory (RAM, RandomAccessMemory), mobile hard disk, magnetic disk or optical disk, etc., which can store program code.

[0128] It can be understood that the above embodiments are only used to illustrate the technical solutions of the present invention rather than to limit it. Although the present invention has been described in detail with reference to the above embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the above embodiments, or replace some or all of the technical features therein by equivalents. These modifications or replacements do not make the essence of the corresponding technical solutions deviate from the scope of the technical solutions of the embodiments of the present invention, and they should all be included in the scope of the claims and specification of the present invention.

Claims

1. A rural power grid capacity planning method considering overload risk, characterized in that: include: Collect and analyze historical load data of the regional power grid, and calculate the capacity limit of photovoltaic access in the single radiation power supply mode and the hand-in-hand power supply mode; The objective function of the rural power grid capacity planning model is constructed with reducing grid vulnerability and active power loss as target parameters; Determining constraints of a rural power grid capacity planning model, wherein the constraints include power balance constraints and voltage constraints; The target rural power grid capacity planning scheme is determined by planning the photovoltaic installed capacity of each load point under the single radiation power supply mode and the hand-in-hand power supply mode.

2. The rural power grid capacity planning method considering overload risk according to claim 1 is characterized in that: The collecting and analyzing of the historical load data of the regional power grid and the calculation of the capacity limit of photovoltaic access in the single radiation power supply mode and the hand-in-hand power supply mode respectively include: The calculation formula for the photovoltaic access capacity limit under the single radiation power supply mode is: S max <S con,max Where: S con,max is the maximum apparent power, and is the maximum active power and maximum reactive power, S max is the maximum power flow after connecting to the distributed photovoltaic power source, P con,mid and They are the minimum load active and reactive power and the minimum load reactive power respectively.

3. The rural power grid capacity planning method considering overload risk according to claim 2 is characterized in that: The collecting and analyzing of the historical load data of the regional power grid and the calculation of the capacity limit of photovoltaic access in the single radiation power supply mode and the hand-in-hand power supply mode respectively include: The calculation formula for the capacity limit of photovoltaic access in the hand-in-hand power supply mode is: Where: P gen1,max and P con1,min are the maximum power generation of the photovoltaic power sources connected to feeder 1 and feeder 2, respectively. and are the maximum apparent power of the loads on feeder 1 and feeder 2, respectively, P con1,min and P con2,min are the active powers corresponding to the minimum loads on feeder 1 and feeder 2, respectively. and are the reactive powers corresponding to the minimum loads on feeder 1 and feeder 2, respectively, (P gen1 +P gen2 ) max is the maximum total power of the photovoltaic power sources connected to the two feeders, is the maximum apparent power of the total load of the two feeders, is the total reactive power corresponding to the minimum load of the two feeders, (P con1 +P con2 ) min is the total active power corresponding to the minimum load of the two feeders.

4. The rural power grid capacity planning method considering overload risk according to claim 1, characterized in that: The objective function of the rural power grid capacity planning model constructed with reducing power grid vulnerability and reducing active power loss as target parameters includes: The expression of the objective function with reducing grid vulnerability as the target parameter is: f1=λ1BV(t)+λ2J(t) Where: BV(t) is the average vulnerability of the power grid, J(t) is the equilibrium degree of vulnerability distribution of each node in the network, J(t)∈[0,1], from 0 to l from absolute imbalance to absolute balance, λ1 and λ2 are the corresponding weight coefficients, N is the number of nodes, V(t,i) is the voltage value of node i at time t, p t,i is the probability of an event affecting grid vulnerability occurring at node i at time t.

5. The rural power grid capacity planning method considering overload risk according to claim 4 is characterized in that: The objective function of the rural power grid capacity planning model constructed with reducing power grid vulnerability and reducing active power loss as target parameters includes: The expression of the objective function with reducing active power loss as the target parameter is: Where: M L For all branches, G ij is the conductance of nodes i and j, U i,t and U j,t are the voltages of nodes i and j at time t, δ ij,t is the phase angle difference between nodes i and j at time t.

6. The rural power grid capacity planning method considering overload risk according to claim 1, characterized in that: The constraint conditions of determining the rural power grid capacity planning model, wherein the constraint conditions include power balance constraints and voltage constraints, include: Power balance constraints: Where: N DG and N sre are the number of distributed power and energy storage devices, respectively, DG,i (t) is the active power of the ith DG at time t, p store,j (t) is the charge and discharge power of the jth energy storage device at time t, p loαl (t) and P LOSS,j (t) is the system load and active network loss at time t; Voltage Constraints: in: and are the lower and upper voltage limits of node i, V i is the voltage at node i.

7. The rural power grid capacity planning method considering overload risk according to claim 1, characterized in that: The target rural power grid capacity planning scheme is determined by planning the photovoltaic installed capacity of each load point under the single radiation power supply mode and the hand-in-hand power supply mode, including: Based on the single radiation power supply mode, key parameters are extracted by collecting historical load data of the regional power grid; at the same time, the maximum allowable photovoltaic installation capacity of each load point is determined; Based on the hand-in-hand power supply mode, the historical load data of the single section and the entire feeder area are collected and relevant parameters are extracted. The maximum photovoltaic installation capacity of each load point is determined by calculating and comparing the photovoltaic power generation capacity of each area.

8. A rural power grid capacity planning system considering overload risk, characterized in that: include: The capacity limit calculation unit is used to collect and analyze the historical load data of the regional power grid, and calculate the capacity limit of photovoltaic access in the single radiation power supply mode and the hand-in-hand power supply mode respectively; An objective function building unit is used to build an objective function of a rural power grid capacity planning model with reducing power grid vulnerability and reducing active power loss as target parameters; A constraint determination unit, used to determine the constraint of the rural power grid capacity planning model, wherein the constraint includes a power balance constraint and a voltage constraint; The target rural power grid capacity planning scheme determination unit is used to determine the target rural power grid capacity planning scheme by planning the photovoltaic installed capacity of each load point under the single radiation power supply mode and the hand-in-hand power supply mode.

9. A computer device, characterized in that: include: memories, transceivers, processors, and bus systems; Wherein, the memory is used to store programs; The processor is used to execute the program in the memory, including executing the rural power grid capacity planning method considering overload risk according to any one of claims 1 to 7; The bus system is used to connect the memory and the processor so that the memory and the processor can communicate with each other.

10. A readable storage medium, characterized in that: The method comprises instructions, which, when executed on a computer, enable the computer to execute the steps of the rural power grid capacity planning method considering overload risk as claimed in any one of claims 1 to 7.

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