Low-voltage distribution network commutation interconnection collaborative planning method adaptive to single / three-phase load

Abstract

The invention discloses a low-voltage power distribution network phase change interconnection collaborative planning method adaptive to a single / three-phase load, and aims at solving the problems that in a low-voltage power distribution network single / three-phase load access and fault scene, the recovery means in an existing phase change switch and line-line interconnection switch deployment planning scheme is single, and the power supply reliability and economy are difficult to consider at the same time. According to the switch deployment method provided by the invention, low-voltage power distribution network phase-change switch configuration, line-line interconnection switch configuration and fault scene action selection are taken as decision variables, and minimum investment cost and power failure loss cost of the phase-change switch and the line-line interconnection switch are taken as objective functions; the constraint conditions comprise a commutation capacity constraint, an interconnection capacity constraint, an action mutual exclusion constraint and a reliability constraint, ensuring the feasibility of the planning scheme, solving by using a mixed integer programming algorithm to obtain an optimal configuration scheme of the low-voltage distribution network commutation switch and the line-line interconnection equipment, and ensuring the reliability of the single / three-phase load while ensuring the reliable power supply of the single / three-phase load. Cooperative improvement of economy and reliability is achieved, and powerful support is provided for low-voltage distribution network phase-change switch planning and line-line interconnection planning.

Description

Technical Field

[0001] This invention relates to the field of low-voltage distribution network equipment planning technology, and to a low-voltage distribution network interconnection and collaborative planning method adapted to single / three-phase loads. Background Technology

[0002] As the final link of the power system, the low-voltage distribution network directly bears the power supply demand of single-phase residential loads and three-phase industrial and commercial loads. Its power supply reliability and economy directly affect the user's electricity experience and system operation efficiency. With the diversification of user load types and the rigid growth of electricity demand, the load recovery capability under fault scenarios has become one of the core objectives of distribution network planning. As two key recovery methods, the importance of phase-switching switches and line-to-line interconnection equipment is mainly reflected in: (1) In terms of fault recovery: multi-level interconnection accurately improves the fault response capability. For faults caused by single-phase loads, the phase load is switched by phase-switching switches; for three-phase lines or neutral line faults, line-to-line interconnection transfers the load to ensure that the key loads are not interrupted. (2) In terms of optimized operation: phase-to-phase interconnection can balance the load and reduce line redundancy investment; line-to-line interconnection improves the line utilization efficiency and reduces the reserve capacity configuration.

[0003] However, existing planning methods for phase-to-phase (PTP) interconnection in low-voltage distribution networks, adapted to single / three-phase loads, have significant shortcomings and are difficult to adapt to the complex scenarios of mixed single / three-phase loads. Firstly, existing PTP location methods do not consider the potential for reliability improvement. Current planning schemes often focus on addressing three-phase imbalance under normal operation, failing to explore the reliability improvement potential of PTP in single-phase fault scenarios, resulting in limited equipment functionality and underutilized fault recovery capabilities. Secondly, existing methods lack coordinated planning between PTP and line-to-line interconnections. Current planning methods for PTP and line-to-line interconnections in low-voltage distribution networks generally involve independent planning without coordinated design. Specifically, planning only PTP is insufficient for recovering three-phase faults, while planning only line-to-line interconnections can lead to over-recovery, making it difficult to flexibly adapt to fault types and load distributions for reliable power supply. Furthermore, they neglect the constraint coupling relationships required for coordinated PTP and line-to-line interconnection, easily leading to operational conflicts or failure to meet actual operational needs, resulting in low feasibility of the planning schemes. Therefore, constructing a collaborative planning model for phase-switching switches and line-to-line interconnection equipment that can adapt to single / three-phase loads, and realizing the collaborative configuration and operation optimization of the two types of equipment, has become a key issue that urgently needs to be addressed in the field of low-voltage distribution network planning. Summary of the Invention

[0004] This invention aims to solve problems such as independent design, functional mismatch, and constraint conflicts in the planning of existing low-voltage distribution network phase-switching switches and line-to-line interconnection equipment. It provides a collaborative planning method for low-voltage distribution network phase-switching interconnection adapted to single / three-phase loads, achieving global optimization of equipment configuration and fault recovery. Specifically, it includes:

[0005] (1) Based on the connection relationship between three-phase lines and single-phase lines in the low-voltage distribution network, construct a low-voltage power supply system topology adapted to single / three-phase loads, generate a fault state matrix, a phase-switching switch action matrix, and a line-to-line interconnection switch action matrix under different fault scenarios, and quantify the switching action logic under different fault states.

[0006] (2) Based on the operation of the phase-switching switch and the line-to-line interconnection switch, a calculation model for the load recovery and power loss of the low-voltage distribution network is constructed to obtain the power outage of the low-voltage distribution network.

[0007] (3) Construct a low-voltage distribution network phase-switching interconnection collaborative planning optimization model, define the phase-switching switch configuration vector, the line-to-line interconnection switch configuration matrix and the fault scenario action selection vector as decision variables, and use the mixed integer programming algorithm to solve the model to obtain the optimal configuration scheme of phase-switching switches and line-to-line interconnection switches.

[0008] The specific process of step (1) is as follows:

[0009] 1) The low-voltage power supply system topology adapted to single / three-phase loads, constructed according to the connection relationship between three-phase and single-phase lines in the low-voltage distribution network as described in this application, specifically includes: constructing a load connection relationship matrix and a load power vector adapted to single / three-phase loads. A load connection relationship matrix characterizing the topology parameters of the low-voltage distribution network is defined, and a three-level topology system of "line-phase-load" is constructed, including the number of lines N. L Number of phases per line (Phase A / B / C), Total number of "Line-Phase" And the total number of loads M, including single-phase and three-phase loads.

[0010] 2) Further, establish the load connection matrix S∈{0,1} NLP×M Where S(i,j)=1 indicates that the j-th load is connected to the i-th "line-phase", a single-phase load corresponds to a row index of 1 in the matrix, and a three-phase load corresponds to a row index of 1 in the matrix. Define a load power vector representing the load parameters. This represents the total power of each load. The power of the three-phase load is evenly distributed to the three "line-phases" to which it is connected.

[0011] 3) Furthermore, the switching action logic under different fault states is quantified by generating fault state matrices, commutation switch action matrices, and line-to-line interconnection switch action matrices for different fault scenarios. This includes the following three parts:

[0012] (a) Fault state matrix F s ∈{0,1} NLP×1 F s (i) = 1 indicates that the i-th "line-phase" is faulty in scenario s;

[0013] (b) Commutation switch operation matrix

[0014] The phase-switching switch action matrix is ​​used to characterize whether, under fault scenario s, the i-th load can be switched to the j-th "line-phase" via a phase-switching switch. Its action logic requires the following three conditions to be met simultaneously: Condition 1: A phase-switching switch exists on the "line-phase" containing the i-th load; Condition 2: The j-th "line-phase" of the target phase is normal; Condition 3: After the i-th load is switched to the j-th "line-phase," the total power of the original load power plus the switched load power of that "line-phase" satisfies the phase-switching capacity constraint, i.e., it is less than the maximum carrying capacity. Only when all three conditions are met simultaneously will the elements of the action matrix be 1, thus obtaining the phase-switching switch action matrix.

[0015]

[0016] In the formula, X×1 1×M There exists a marker matrix for the commutation switch; For normal phase labeling matrix; C s C is the commutation capacity constraint matrix. s (i,j)=1 indicates that the total power after the j-th load is switched to the i-th "line-phase" is ≤S max C s (i,j) = 0 indicates overload after switching, i.e., the capacity constraint is not met. represents the Hadamard product of matrices, i.e., the product of corresponding elements.

[0017] (c) Line-to-line interconnection switch action matrix

[0018] The line-to-line interconnection switch action matrix is ​​used to characterize whether, under fault scenario s, the power loss load of the i-th "line-phase" can be transferred to the k-th "line-phase" via the line-to-line interconnection switch. Its action logic requires the simultaneous fulfillment of the following four conditions: Condition 1: A line-to-line interconnection switch is installed between the two lines belonging to the power loss "line-phase" i and the target "line-phase" k; Condition 2: The power loss "line-phase" i and the target "line-phase" k belong to different lines; Condition 3: The target line for the line-to-line interconnection conversion is a normal line; Condition 4: After the power loss load of the i-th "line-phase" is transferred to the k-th "line-phase", the total power of the original load power of the target "line-phase" k and the transferred load power satisfies the interconnection capacity constraint, i.e., it is less than the maximum carrying capacity S. max The action matrix element is only 1 when all four conditions are met simultaneously, thus obtaining the line-to-line interconnection switch action matrix.

[0019]

[0020] In the formula, Y exp The extended matrix for interconnection switches represents condition one, namely whether there is a line-to-line interconnection switch installed between the two lines to which the power-out "line-phase" i and the target "line-phase" k belong. Its construction logic is as follows: if the interconnection switch configuration matrix element Y(x1,x2) = 1 for lines x1 and x2, then all "line-phases" of line x1 and all "line-phases" of line x2 correspond to Y. exp All elements in the array are 1, enabling three-way interconnection and transfer. The cross-line marking matrix represents condition two, namely, the power-loss "line-phase" i and the target "line-phase" k belong to different lines. Here, diag(.) is the constructor of the diagonal matrix, and the parameters in the parentheses represent the diagonal elements. The normal line marking matrix represents condition three, namely, the target line for line-to-line interconnection conversion must be a normal line. (C) link,s Let C be the interconnection capacity constraint matrix, representing condition four. link,s (i,k)=1 indicates that the total power after the load of the i-th "line-phase" is transferred to the k-th "line-phase" is ≤S max C link,s (i,k)=0 indicates that the target line is overloaded after the line-to-line interconnection conversion and does not meet the capacity constraint. represents the Hadamard product of matrices, i.e., the multiplication of corresponding elements.

[0021] The specific process of step (2) is as follows:

[0022] 1) Based on the operating states of the phase-switching switch and the line-to-line interconnection switch, a calculation model for load restoration and power loss of low-voltage distribution network is constructed, and the power outage of low-voltage distribution network is calculated through this model.

[0023] 2) Furthermore, in order to realize the calculation of load restoration and power loss in low-voltage distribution networks, a load restoration and power loss calculation model is constructed, including the initial power loss load, the load restored by commutation, the load restored by interconnection, and the final power loss.

[0024] 3) Furthermore, the initial power loss load is expressed as: An initial power outage occurs if any "line-phase" fault occurs in the load j connection.

[0025] 4) Furthermore, the commutation recovery load is expressed as: A single-phase load that has only experienced an initial power loss can be restored by commutation;

[0026] 5) Furthermore, the interconnection recovery load is expressed as: Loads that have not been restored by commutation can be restored through interconnection and transfer.

[0027] 6) Furthermore, the final power loss is expressed as:

[0028]

[0029] In the formula, sign(.) is the sign function, which satisfies the following conditions: output 1 when the input value > 0, and output 0 when the input value = 0; commutation recovery load amount The element corresponding to a three-phase load is forced to 0; power supply to a single-phase load can be restored via a phase-switching switch; interconnected load restoration Both single-phase and three-phase loads can be 1, and line-to-line interconnection can restore all types of power-loss loads.

[0030] The specific process of step (3) is as follows:

[0031] 1) Construct a low-voltage distribution network interconnection collaborative planning optimization model with the objective function of minimizing the sum of the total investment cost of switches and the power outage loss cost, and the decision variables being the phase-switching switch configuration vector, the line-to-line interconnection switch configuration matrix, and the fault scenario action selection vector. The constraints include phase-switching capacity constraints, interconnection capacity constraints, action mutual exclusion constraints, and reliability constraints. Solve the model using a mixed integer programming algorithm to obtain the optimal configuration scheme of phase-switching switches and line-to-line interconnection switches.

[0032] 2) Furthermore, the objective function of the low-voltage distribution network phase-switching interconnection collaborative planning optimization model is used to characterize the minimization of total cost. The objective function takes the minimization of the sum of total investment cost and annual power outage loss cost as the optimization direction, and quantifies the reliability index through power outage loss cost, so as to achieve a balance between the economy and reliability of the phase-switching switch and line-to-line interconnection switch installation scheme.

[0033] 3) Furthermore, the objective function is to minimize the total cost over the entire life cycle, including both total investment cost and average annual power outage loss cost, i.e., minC total =C inv +C loss C inv C represents the total investment cost of the equipment. loss This represents the average annual cost of power outage losses. Details are as follows:

[0034] (a) Total investment cost C inv The calculation formula is:

[0035]

[0036] Where c PSC The investment cost per unit of commutator switch (RMB / unit), c linkThe cost of a single set of interconnected line switches is (RMB / set). Phase-changing switches are counted by "line-phase", and interconnected line switches are counted by "line pair" to avoid double counting.

[0037] (b) Average annual power outage loss cost C loss The calculation formula is:

[0038]

[0039] Where c loss The unit power hour power outage loss is expressed as (yuan / (kW·h)), t fix f is the mean time to repair (MTBL) for each fault (hours / f). s Let s be the annual failure frequency (times / year). By traversing all failure scenarios, the average annual total power outage loss is calculated cumulatively.

[0040] 4) Further, the decision variables are defined, clarifying the dimensions and physical meaning of each variable. This is used to define the phase-switching switch configuration vector X, the line-to-line interconnection switch configuration matrix Y, and the fault scenario action selection vector Z. Specifically, the phase-switching switch configuration vector X represents the decision result of whether to install a phase-switching switch at each "line-phase" location in the low-voltage distribution network. It is a discrete decision regarding whether to install or not install the phase-switching switch hardware. This vector only applies to the "line-phase" corresponding to a single-phase load; three-phase loads cannot be switched via phase-switching switches, and the corresponding location is forced to 0. The line-to-line interconnection switch configuration matrix Y represents the decision result of whether to install a three-phase interconnection switch between any two lines. It is a discrete decision regarding the interconnection hardware configuration between lines. The diagonal elements of this vector are forced to 0, meaning that lines will not self-interconnect. This vector only applies to interconnections between different lines and is a symmetrical upper triangular matrix. The fault scenario action selection vector Z represents the decision result of choosing "activate the commutation switch" or "activate the line-to-line interconnection switch" for fault recovery under each fault scenario. It is a discrete decision of the fault handling strategy. For each fault scenario, the commutation or interconnection strategy can only be selected, so as to avoid repeated actions that would lead to cost waste or operational conflicts.

[0041] 5) Further, establish a decision variable vector, including the commutation switch configuration vector X∈{0,1}. NLP×1 Line-to-line interconnection switch configuration matrix Y∈{0,1} NL×NL and the action selection vector Z∈{0,1} for the fault scenario |Ω|×1 The dimensions, value rules, and definitions of each variable are as follows:

[0042] (a) Commutation switch configuration vector X∈{0,1} NLP×1 Line-to-line interconnection switch configuration matrix Y∈{0,1} NL×NL and the action selection vector Z∈{0,1} for the fault scenario |Ω|×1Where X(i) = 1 indicates that a phase-changing switch is installed for the single-phase load of the i-th "line-phase", and the corresponding position of the three-phase load is forced to 0.

[0043] (b) The configuration matrix Y of the line interconnection switch is a symmetric upper triangular matrix that satisfies Y(x1,x2)=Y(x2,x1), and the diagonal element Y(x,x)=0 to avoid line self-interconnection; Y(x1,x2)=1 indicates that three interconnection switches are installed on lines x1 and x2.

[0044] (c) The dimension of the fault scenario action selection vector Z is the same as the number of elements in the fault scenario set Ω, and each scenario corresponds to only one action selection for commutation or interconnection. Ω = Ω single ∪Ω three Ω is a set of fault scenarios. single Contains N LP A single-phase fault scenario, Ω three Contains N L In a three-phase fault scenario, Z(s) = 1 indicates that the phase switching switch is activated in scenario s, and Z(s) = 0 indicates that the line-to-line interconnection switch is activated.

[0045] 6) Furthermore, to ensure the rationality, feasibility, and engineering constraint adaptability of the optimization model's solution results, the optimization model is equipped with constraints. These constraints are used to limit the values ​​of decision variables, switching actions, and capacity matching. Specifically, they include:

[0046] (a) The commutation capacity constraint includes:

[0047]

[0048] Where i′∈sameline represents other phases belonging to the same line as the i-th “line-phase”, the constraint logic is: the sum of the original load power of any “line-phase” and the load power connected by the commutation does not exceed the maximum carrying capacity, so as to avoid the line overload caused by the commutation.

[0049] (b) The interconnection capacity constraints include:

[0050]

[0051] The constraint logic is: the sum of the original load power of any "line-phase" and the load power of the interconnected connection shall not exceed the maximum carrying capacity, so as to avoid line overload caused by interconnection and power transfer.

[0052] (c) The mutual exclusion constraint of the actions includes:

[0053] Action mutual exclusion constraints consist of two core inequalities, used to force only one action of either the commutation switch or the line-to-line interconnection switch to be activated under the same fault scenario. The mathematical expression is:

[0054] Constraint 1: Interconnection actions are invalid when commutation is enabled.

[0055]

[0056] Constraint 2: Commutation is invalid when interconnection is enabled.

[0057]

[0058] Where link_valid(s,x1,x2)=1 indicates that the interconnection of lines x1 and x2 is valid under scenario s, and psc_valid(s,i)=1 indicates that the phase commutation of "line-phase" i is valid under scenario s. The constraint logic is that only one action, either phase commutation or interconnection, is allowed under the same fault scenario to avoid duplicate actions and cost waste.

[0059] (d) The reliability constraints include:

[0060]

[0061] In the formula, ASAI min For the minimum permissible power supply reliability, R s f represents the load recovery rate for scenario s. s Let t be the annual failure frequency of scenario s. fix The mean time to repair faults is defined as the average fault repair time. The constraint logic is that the system's annual average power supply reliability (ASAI) under all fault scenarios must not be lower than the reliability baseline, ensuring that the planning scheme meets industry power supply reliability standards.

[0062] 7) Further, the optimal configuration scheme and action strategy are solved by integer programming algorithm, and the optimal configuration scheme is output, including the phase switching configuration vector X, the line-to-line interconnection switch configuration matrix Y, and the fault scenario action strategy, i.e., the action selection vector Z.

[0063] 8) Furthermore, output the costs associated with this plan, including the total investment cost C. inv Average annual power outage loss C loss Total life cycle cost C total This provides a basis for decision-making in engineering practice.

[0064] The advantages of this invention are as follows: First, it establishes a three-level topology quantification model of "line-phase-load" adapted to single / three-phase loads, accurately distinguishing the fault response characteristics of the two types of loads; second, it proposes mutual exclusion constraints and capacity coupling constraints for commutation and interconnection, avoiding operational conflicts and line overload; third, it achieves global optimization of cost and reliability, avoiding the functional limitations of single equipment planning, and adapting to different fault scenarios through action strategies, thereby improving the feasibility and economy of the planning scheme. Attached Figure Description

[0065] AppendixFigure 1 This is a flowchart illustrating a low-voltage distribution network interconnection and collaborative planning method adapted to single / three-phase loads provided by the present invention.

[0066] Appendix Figure 2 This is a schematic diagram of the low-voltage active distribution network topology provided by the present invention, including distribution transformers, three-phase lines, single-phase lines, and load points. The diagram also illustrates the interconnection structure between lines and between phases, which is used to explain the structure of line interconnection and phase commutation of the low-voltage distribution network involved in the present invention. Detailed Implementation

[0067] To make the objectives, technical solutions, and advantages of this invention clearer, the implementation process of the low-voltage distribution network interconnection and coordinated planning method adapted to single / three-phase loads described in this invention will be explained in detail below with reference to the accompanying drawings and embodiments. Those skilled in the art can implement the evaluation process of this invention based on the following description and specific power grid data.

[0068] Step 1: Construct the system topology and parameter modeling module.

[0069] This step aims to abstract the actual physical power grid into a mathematical model, laying the foundation for subsequent calculations.

[0070] (1) Construct a low-voltage power supply topology matrix to represent the connection relationships between three-phase and single-phase lines in the low-voltage distribution network. Specifically, this includes: a load connection matrix S, a load power vector P, and setting topology parameters, cost parameters, and reliability parameters. Define general topology parameters and load parameters for the low-voltage distribution network, and construct a three-level topology system of "line-phase-load," including the number of lines N. L Number of phases per line That is, the total number of three phases A / B / C and "line-phase" connections. The total load includes single-phase loads and three-phase loads M.

[0071] (2) Establish the load connection matrix S∈{0,1} NLP×M Where S(i,j)=1 indicates that the j-th load is connected to the i-th "line-phase", a single-phase load corresponds to a row index of 1 in the matrix, and a three-phase load corresponds to a row index of 1 in the matrix; define the load power vector. The total power of each load is represented, with the three-phase load power evenly distributed to the three connected "line-phases"; the maximum carrying capacity S of each phase is set. max This serves as a capacity constraint threshold for commutation switching and interconnection power transfer.

[0072] Step 2: Construct a fault state and action matrix quantification module to generate fault states, commutation switch action matrices, and line-to-line interconnection switch action matrices for fault scenarios. The purpose of this step is to quantify the relationship between fault states and action logic.

[0073] (1) Fault state matrix F s ∈{0,1} NLP×1 F s (i) = 1 indicates that the i-th "line-phase" is faulty in scenario s;

[0074] (2) Commutation switch action matrix

[0075] The phase-switching switch action matrix is ​​used to characterize whether, under fault scenario s, the i-th load can be switched to the j-th "line-phase" via a phase-switching switch. Its action logic requires the following three conditions to be met simultaneously: Condition 1: A phase-switching switch exists on the "line-phase" containing the i-th load; Condition 2: The j-th "line-phase" of the target phase is normal; Condition 3: After the i-th load is switched to the j-th "line-phase," the total power of the original load power plus the switched load power of that "line-phase" satisfies the phase-switching capacity constraint, i.e., it is less than the maximum carrying capacity. Only when all three conditions are met simultaneously will the elements of the action matrix be 1, thus obtaining the phase-switching switch action matrix.

[0076]

[0077] In the formula, X×1 1×M There exists a marker matrix for the commutation switch; For normal phase labeling matrix; C s C is the commutation capacity constraint matrix. s (i,j)=1 indicates that the total power after the j-th load is switched to the i-th "line-phase" is ≤S max C s (i,j) = 0 indicates overload after switching, i.e., the capacity constraint is not met. represents the Hadamard product of matrices, i.e., the product of corresponding elements.

[0078] (3) Line-to-line interconnection switch action matrix

[0079] The line-to-line interconnection switch action matrix is ​​used to characterize whether, under fault scenario s, the power loss load of the i-th "line-phase" can be transferred to the k-th "line-phase" via the line-to-line interconnection switch. Its action logic requires the simultaneous fulfillment of the following four conditions: Condition 1: A line-to-line interconnection switch is installed between the two lines belonging to the power loss "line-phase" i and the target "line-phase" k; Condition 2: The power loss "line-phase" i and the target "line-phase" k belong to different lines; Condition 3: The target line for the line-to-line interconnection conversion is a normal line; Condition 4: After the power loss load of the i-th "line-phase" is transferred to the k-th "line-phase", the total power of the original load power of the target "line-phase" k and the transferred load power satisfies the interconnection capacity constraint, i.e., it is less than the maximum carrying capacity S. max The action matrix element is only 1 when all four conditions are met simultaneously, thus obtaining the line-to-line interconnection switch action matrix.

[0080]

[0081] In the formula, Y exp The extended matrix for interconnection switches represents condition one, namely whether there is a line-to-line interconnection switch installed between the two lines to which the power-out "line-phase" i and the target "line-phase" k belong. Its construction logic is as follows: if the interconnection switch configuration matrix element Y(x1,x2) = 1 for lines x1 and x2, then all "line-phases" of line x1 and all "line-phases" of line x2 correspond to Y. exp All elements in the array are 1, enabling three-way interconnection and transfer. The cross-line marking matrix represents condition two, namely, the power-loss "line-phase" i and the target "line-phase" k belong to different lines. Here, diag(.) is the constructor of the diagonal matrix, and the parameters in the parentheses represent the diagonal elements. The normal line marking matrix represents condition three, namely, the target line for line-to-line interconnection conversion must be a normal line. (C) link,s Let C be the interconnection capacity constraint matrix, representing condition four. link,s (i,k)=1 indicates that the total power after the load of the i-th "line-phase" is transferred to the k-th "line-phase" is ≤S max C link,s (i,k)=0 indicates that the target line is overloaded after the line-to-line interconnection conversion and does not meet the capacity constraint. represents the Hadamard product of matrices, i.e., the multiplication of corresponding elements.

[0082] Step 3: Construct a load restoration and power loss calculation module. This step calculates the initial power loss load. Commutation recovery load Interconnection recovery load and final power loss The amount of power outage is obtained, which forms the subsequent reliability index constraint for the model.

[0083] (a) Initial power loss load An initial power outage occurs if any "line-phase" fault occurs in the load j connection.

[0084] (b) Commutation recovery load A single-phase load that has only experienced an initial power loss can be restored by commutation;

[0085] (c) Interconnection recovery load Loads that have not been restored by commutation can be restored through interconnection and power transfer;

[0086] (d) Final power loss

[0087] Step 4: Construct the objective function, decision variables, and constraints of a low-voltage distribution network interconnection collaborative planning and optimization model adapted to single / three-phase loads. The objective function is to minimize the total cost. The decision variables are the commutation switch configuration vector, the line-to-line interconnection switch configuration matrix, and the fault scenario action selection vector. The constraints include commutation capacity constraints, interconnection capacity constraints, action mutual exclusion constraints, and reliability constraints. Details are as follows:

[0088] (a) Total investment cost C inv The calculation formula is:

[0089]

[0090] Where c PSC The investment cost per unit of commutator switch (RMB / unit), c link The cost of a single set of interconnected line switches is (RMB / set). Phase-changing switches are counted by "line-phase", and interconnected line switches are counted by "line pair" to avoid double counting.

[0091] (b) Average annual power outage loss cost C loss The calculation formula is:

[0092]

[0093] Where c loss The unit power hour power outage loss is expressed as (yuan / (kW·h)), t fix f is the mean time to repair (MTBL) for each fault (hours / f). s Let s be the annual failure frequency (times / year). By traversing all failure scenarios, the average annual total power outage loss is calculated cumulatively.

[0094] (c) The decision variables specifically include the commutation switch configuration vector, the line-to-line interconnection switch configuration matrix, and the fault scenario action selection vector. The dimensions, value rules, and definitions of each variable are as follows: Commutation switch configuration vector X∈{0,1} NLP×1 Line-to-line interconnection switch configuration matrix Y∈{0,1} NL×NL and the action selection vector Z∈{0,1} for the fault scenario |Ω|×1 Where X(i) = 1 indicates that a phase-switching switch is installed for the i-th "line-phase" single-phase load, and the corresponding position for three-phase loads is forced to 0. The line-to-line interconnection switch configuration matrix Y is a symmetric upper triangular matrix, satisfying Y(x1,x2) = Y(x2,x1), with diagonal elements Y(x,x) = 0 to avoid line self-interconnection; Y(x1,x2) = 1 indicates that a three-phase interconnection switch is installed for lines x1 and x2. The dimension of the fault scenario action selection vector Z is consistent with the number of elements in the fault scenario set Ω, and each scenario corresponds to only one action selection: phase-switching or interconnection. Ω = Ω single ∪Ω threeFor a set of fault scenarios, Ωsingle contains N LP A single-phase fault scenario, Ω three Contains N L In a three-phase fault scenario, Z(s) = 1 indicates that the phase switching switch is activated in scenario s, and Z(s) = 0 indicates that the line-to-line interconnection switch is activated.

[0095] (d) Constraints ensure the rationality, feasibility, and engineering constraint adaptability of the optimization model's solution results. The optimization model is equipped with constraints that limit the values ​​of decision variables and the engineering boundaries of switching actions and capacity matching. Specifically, these constraints include:

[0096] The commutation capacity constraint includes:

[0097]

[0098] Where i′∈sameline represents other phases belonging to the same line as the i-th “line-phase”, the constraint logic is: the sum of the original load power of any “line-phase” and the load power connected by the commutation does not exceed the maximum carrying capacity, so as to avoid the line overload caused by the commutation.

[0099] The interconnection capacity constraints include:

[0100]

[0101] The constraint logic is: the sum of the original load power of any "line-phase" and the load power of the interconnected connection shall not exceed the maximum carrying capacity, so as to avoid line overload caused by interconnection and power transfer.

[0102] The mutual exclusion constraint for the actions includes:

[0103] Action mutual exclusion constraints consist of two core inequalities, used to force only one action of either the commutation switch or the line-to-line interconnection switch to be activated under the same fault scenario. The mathematical expression is:

[0104] Constraint 1: Interconnection actions are invalid when commutation is enabled.

[0105]

[0106] Constraint 2: Commutation is invalid when interconnection is enabled.

[0107]

[0108] Where link_valid(s,x1,x2)=1 indicates that the interconnection of lines x1 and x2 is valid under scenario s, and psc_valid(s,i)=1 indicates that the phase commutation of "line-phase" i is valid under scenario s. The constraint logic is that only one action, either phase commutation or interconnection, is allowed under the same fault scenario to avoid duplicate actions and cost waste.

[0109] The reliability constraints include:

[0110]

[0111] In the formula, ASAI min For the minimum permissible power supply reliability, R s f represents the load recovery rate for scenario s. s Let t be the annual failure frequency of scenario s. fix The mean time to repair faults is defined as the average fault repair time. The constraint logic is that the system's annual average power supply reliability (ASAI) under all fault scenarios must not be lower than the reliability baseline, ensuring that the planning scheme meets industry power supply reliability standards.

[0112] Step 5: Result Output Module

[0113] The optimal configuration scheme is solved using a mixed integer programming algorithm, including the commutator switch configuration vector X, the line-to-line interconnection switch configuration matrix Y, the fault scenario action strategy (action selection vector Z), and the total investment cost C. inv Average annual power outage loss C loss Total life cycle cost C total To provide a basis for decision-making in engineering practice.

[0114] Finally, it should be noted that the above-described embodiments are merely specific implementations of the present invention, used to illustrate the technical solutions of the present invention, and not to limit it. The scope of protection of the present invention is not limited thereto. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that any person skilled in the art can still modify or easily conceive of changes to the technical solutions described in the foregoing embodiments within the technical scope disclosed in the present invention, or make equivalent substitutions for some of the technical features; and these modifications, changes, or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention, and should all be covered within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be determined by the scope of the claims.

Claims

1. A low-voltage distribution network interconnection and collaborative planning method adapted to single / three-phase loads, characterized in that: (1) Based on the connection relationship between three-phase lines and single-phase lines in the low-voltage distribution network, construct a low-voltage power supply system topology adapted to single / three-phase loads, generate a fault state matrix, a phase-switching switch action matrix, and a line-to-line interconnection switch action matrix under different fault scenarios, and quantify the switching action logic under different fault states. (2) Based on the operation of the phase-switching switch and the line-to-line interconnection switch, a calculation model for the load recovery and power loss of the low-voltage distribution network is constructed to obtain the power outage of the low-voltage distribution network. (3) Construct a low-voltage distribution network phase-switching interconnection collaborative planning optimization model, define the phase-switching switch configuration vector, the line-to-line interconnection switch configuration matrix and the fault scenario action selection vector as decision variables, and use the mixed integer programming algorithm to solve the model to obtain the optimal configuration scheme of phase-switching switches and line-to-line interconnection switches.

2. The low-voltage distribution network interconnection and collaborative planning method for adapting to single / three-phase loads according to claim 1, characterized in that, Step (1) describes constructing a low-voltage power supply system topology adapted to single / three-phase loads based on the connection relationships between three-phase and single-phase lines in the low-voltage distribution network. Specifically, this includes constructing a load connection matrix and a load power vector adapted to single / three-phase loads. Define a load connection matrix to characterize the topology parameters of a low-voltage distribution network, and construct a three-level topology system of "line-phase-load", including the number of lines N. L Number of phases per line (Phase A / B / C), Total number of "Line-Phase" Given the total number of loads M, including both single-phase and three-phase loads, a load connection matrix S∈{0,1} is established. NLP×M S(i,j)=1 indicates that the j-th load is connected to the i-th "line-phase". The single-phase load corresponds to 1 row index in the matrix, and the three-phase load corresponds to 3 row indexes in the matrix. Define a load power vector that characterizes load parameters. This represents the total power of each load. The power of the three-phase load is evenly distributed to the three "line-phases" to which it is connected.

3. The low-voltage distribution network interconnection and collaborative planning method for adapting to single / three-phase loads according to claim 1, characterized in that, The quantification logic for switching actions under different fault states described in step (1) is achieved by generating fault state matrices, commutation switch action matrices, and line-to-line interconnection switch action matrices for different fault scenarios, as detailed below: The fault state matrix is: F s ∈{0,1} NLP×1 F s (i) = 1 indicates that the i-th "line-phase" is faulty in scenario s; The switching action matrix is ​​used to characterize whether the i-th load can be switched to the j-th "line-phase" through the switching switch under fault scenario s. Its action logic is that the following three conditions must be met simultaneously: Condition 1: A phase-switching switch exists in the "line-phase" where the i-th load is located; Condition 2: The j-th "line-phase" of the target phase is normal; Condition 3: After the i-th load is switched to the j-th "line-phase", the total power of the original load power of the "line-phase" plus the switched load power satisfies the commutation capacity constraint, i.e., it is less than the maximum carrying capacity. Only when all three conditions are met simultaneously will the elements of the action matrix be 1, thus obtaining the commutation switch action matrix: In the formula, X×1 1×M There exists a marker matrix for the commutation switch; For normal phase labeling matrix; C s C is the commutation capacity constraint matrix. s (i,j)=1 indicates that the total power after the j-th load is switched to the i-th "line-phase" is ≤S max C s (i,j)=0 indicates overload after switching, i.e., the capacity constraint is not met, and represents the matrix Hadamard product, i.e., the corresponding elements are multiplied; The line-to-line interconnection switch action matrix is ​​used to characterize whether the power loss load of the i-th "line-phase" can be transferred to the k-th "line-phase" through the line-to-line interconnection switch under fault scenario s. Its action logic is that the following four conditions must be met simultaneously: Condition 1: A line-to-line interconnection switch is installed between the two lines belonging to the power-loss "line-phase" i and the target "line-phase" k; Condition 2: The power-loss "line-phase" i and the target "line-phase" k belong to different lines; Condition 3: The target line for the line-to-line interconnection conversion is a normal line; Condition 4: After the power loss load of the i-th "line-phase" is transferred to the k-th "line-phase", the total power of the original load power of the target "line-phase" k and the transferred load power satisfies the interconnection capacity constraint, that is, it is less than the maximum carrying capacity S. max To ensure that all four conditions are met simultaneously, the action matrix element is 1 only, thus obtaining the line-to-line interconnection switch action matrix: In the formula, Y exp The extended matrix for interconnection switches represents condition one, namely whether there is a line-to-line interconnection switch installed between the two lines to which the de-energized "line-phase" i and the target "line-phase" k belong. Its construction logic is as follows: if the interconnection switch configuration matrix element Y(x1,x2) = 1 for lines x1 and x2, then all "line-phases" of line x1 and all "line-phases" of line x2 correspond to the Y... exp All elements in the array are 1, enabling three-way interconnection and transfer. This is a cross-line marking matrix, representing condition two, namely, the power-loss "line-phase" i and the target "line-phase" k belong to different lines. Here, diag(.) is the constructor for a diagonal matrix, and the parameters within the parentheses represent the diagonal elements. The normal line label matrix represents condition three, namely, the target line for line-to-line interconnection conversion must be a normal line, C. link,s Let C be the interconnection capacity constraint matrix, representing condition four. link,s (i,k)=1 indicates that the total power after the load of the i-th "line-phase" is transferred to the k-th "line-phase" is ≤S max C link,s (i,k)=0 indicates that the target line is overloaded after the line-to-line interconnection conversion and does not meet the capacity constraint. It represents the matrix Hadamard product, that is, the corresponding elements are multiplied.

4. The low-voltage distribution network interconnection and collaborative planning method for adapting to single / three-phase loads according to claim 1, characterized in that, Step (2) constructs a load restoration and power loss calculation model, specifically including: initial power loss load, commutation restoration load, interconnection restoration load, and final power loss. The initial power loss load is expressed as follows: In the formula, an initial power loss occurs when any "line-phase" fault is connected to load j; The commutation recovery load is expressed as: In the formula, only the single-phase load that initially lost power can be restored through commutation; The interconnection recovery load is expressed as: In this formula, loads that have not been restored by commutation can be restored through interconnection and power transfer; The final power loss is expressed as: In the formula, sign(.) is the sign function, which satisfies the following conditions: output 1 when the input value > 0, and output 0 when the input value = 0; commutation recovery load amount The element corresponding to a three-phase load is forced to 0; power supply to a single-phase load can be restored via a phase-switching switch; interconnected load restoration Both single-phase and three-phase loads are 1, and line-to-line interconnection restores all types of power-loss loads.

5. The low-voltage distribution network interconnection and collaborative planning method for adapting to single / three-phase loads according to claim 1, characterized in that, The low-voltage distribution network interconnection collaborative planning optimization model described in step (3) is as follows: A low-voltage distribution network interconnection collaborative planning optimization model is constructed with the objective function of minimizing the sum of the total investment cost of switches and the power outage loss cost (i.e., the total cost). The decision variables are the phase-switching switch configuration vector, the line-to-line interconnection switch configuration matrix, and the fault scenario action selection vector. Constraints include phase-switching capacity constraints, interconnection capacity constraints, action mutual exclusion constraints, and reliability constraints. This model is solved using a mixed-integer programming algorithm to obtain the optimal configuration scheme for phase-switching switches and line-to-line interconnection switches, the optimal action strategy under fault scenarios, and various cost parameters. Specifically, this includes the phase-switching switch configuration vector X, the line-to-line interconnection switch configuration matrix Y, the fault scenario action strategy (i.e., the action selection vector Z), and the total investment cost C. inv Average annual power outage loss C loss and total cost C total .

6. The low-voltage distribution network interconnection and collaborative planning method for adapting to single / three-phase loads as described in claim 5, characterized in that, The objective function of the low-voltage distribution network phase-switching interconnection collaborative planning and optimization model is used to characterize the minimization of total cost. The reliability index is quantified by the power outage loss cost, achieving a balance between the economy and reliability of the phase-switching switch and line-to-line interconnection switch installation scheme. The objective function includes the total investment cost and the average annual power outage loss cost, i.e., minC. total =C inv +C loss C inv C represents the total investment cost of the equipment. loss The annual average power outage loss cost is calculated using a model based on the restoration of low-voltage single / three-phase loads and the amount of power lost. loss : Where c loss The unit power hour power outage loss is expressed as (yuan / (kW·h)), t fix f is the mean time to repair (MTBL) for each fault (hours / f). s Let s be the annual failure frequency (times / year). By traversing all failure scenarios, the average annual total power outage loss is calculated cumulatively.

7. The low-voltage distribution network interconnection and collaborative planning method for adapting to single / three-phase loads as described in claim 5, characterized in that, The decision variables of the low-voltage distribution network interconnection collaborative planning and optimization model specifically include the phase-switching switch configuration vector, the line-to-line interconnection switch configuration matrix, and the fault scenario action selection vector. The dimensions, value rules, and definitions of each variable are as follows: (1) Commutation switch configuration vector X∈{0,1} NLP×1 Line-to-line interconnection switch configuration matrix Y∈{0,1} NL×NL and the action selection vector Z∈{0,1} for the fault scenario |Ω|×1 , where X(i)=1 indicates that the single-phase load of the i-th "line-phase" is equipped with a phase-changing switch, and the corresponding position of the three-phase load is forced to 0; (2) The configuration matrix Y of the line interconnection switch is a symmetrical upper triangular matrix, satisfying Y(x1,x2)=Y(x2,x1), and the diagonal element Y(x,x)=0 to avoid line self-interconnection; Y(x1,x2)=1 indicates that three interconnection switches are installed between lines x1 and x2; (3) The dimension of the fault scenario action selection vector Z is the same as the number of elements in the fault scenario set Ω. Each scenario corresponds to only one action selection for commutation or interconnection, and Ω = Ω single ∪Ω three Ω is a set of fault scenarios. single Contains N LP A single-phase fault scenario, Ω three Contains N L In a three-phase fault scenario, Z(s) = 1 indicates that the phase switching switch is activated in scenario s, and Z(s) = 0 indicates that the line-to-line interconnection switch is activated.

8. The low-voltage distribution network interconnection and collaborative planning method for adapting to single / three-phase loads as described in claim 5, characterized in that, To ensure the rationality, feasibility, and engineering constraint adaptability of the optimization model's solution, the constraints of the low-voltage distribution network interconnection collaborative planning optimization model specifically include: commutation capacity constraints, interconnection capacity constraints, mutual exclusion constraints, and reliability constraints. The commutation capacity constraint includes: In the formula, i′∈sameline represents other phases belonging to the same line as the i-th "line-phase". The constraint logic is: the sum of the original load power of any "line-phase" and the load power connected by the commutation does not exceed the maximum carrying capacity, so as to avoid the line overload caused by the commutation. The interconnection capacity constraints include: The constraint logic is: the sum of the original load power of any "line-phase" and the load power of the interconnected connection shall not exceed the maximum carrying capacity, so as to avoid line overload caused by interconnection and power transfer; The mutual exclusion constraint of the actions includes: Action mutual exclusion constraints consist of two core inequalities, used to force only one action of either the commutation switch or the line-to-line interconnection switch to be activated under the same fault scenario. The mathematical expression is: Constraint 1: Interconnection actions are invalid when commutation is enabled. Constraint 2: Commutation is invalid when interconnection is enabled. In the formula, link_valid(s,x1,x2)=1 indicates that the interconnection of lines x1 and x2 is valid under scenario s, and psc_valid(s,i)=1 indicates that the phase commutation of "line-phase" i is valid under scenario s. The constraint logic is that only one action, either phase commutation or interconnection, is allowed under the same fault scenario to avoid duplicate actions and cost waste. The reliability constraints include: In the formula, ASAI min For the minimum permissible power supply reliability, R s f represents the load recovery rate for scenario s. s Let t be the annual failure frequency of scenario s. fix The mean time to repair faults is defined as the average fault repair time. The constraint logic is that the system's annual average power supply reliability (ASAI) under all fault scenarios must not be lower than the reliability baseline, ensuring that the planning scheme meets industry power supply reliability standards.

9. A low-voltage distribution network interconnection collaborative planning and optimization system, characterized in that, The method includes: a topology and parameter modeling module, used to construct a three-level "line-phase-load" topology system, establish a load connection relationship matrix S and a load power vector P, and set unit outage cost parameters and reliability parameters; and a fault state and action matrix quantization module, used to generate a fault state matrix F for each fault scenario. s Commutation switch action matrix S′ s Line-to-line interconnection switch action matrix T s The module quantifies fault status and switching action logic; the load restoration and power loss calculation module is used to calculate the initial power loss load. Commutation recovery load Interconnection recovery load and final power loss The decision variable module defines the commutation switch configuration vector X, the line-to-line interconnection switch configuration matrix Y, and the fault scenario action selection vector Z, clarifying the dimensions and physical meaning of each variable. The optimization solution module solves the optimal configuration scheme and action strategy using a mixed integer programming algorithm. The result output module outputs the configuration scheme, action strategy, and total cost, providing a basis for decision-making in engineering practice.

10. A computer-readable storage medium having a computer program stored thereon, characterized in that, When the program is executed by the processor, it implements the low-voltage distribution network interconnection and collaborative planning method for adapting to single / three-phase loads as described in any of claims 1 to 8.

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