A radial network ultra-short time scale planning method, medium and system

Abstract

The application provides a radial distribution network ultra-short time scale planning method, medium and system, belongs to radial distribution network planning technical field, and includes: establishing a simulated radial distribution network; setting the state of all line switches in the simulated radial distribution network as opening; calculating the current flowing through each line switch, recorded as switch current; selecting the line switch carrying the minimum current in each network loop, changing the state thereof from opening to closing, taking the line switch in the current closing state as a first switch set; selecting one line switch in the first switch set, and exchanging the state of a switch pair formed by the selected line switch and an optional line switch not in the first switch set in the network loop where the selected line switch is located; repeating the execution until no line switch pair capable of further reducing total power loss is found, finally determining the optimized line switch configuration, and outputting the same to operation and maintenance personnel for radial distribution network planning adjustment.

Description

Technical Field

[0001] This invention belongs to the field of radial distribution network planning technology, and specifically relates to a method, medium, and system for ultra-short time scale planning of radial distribution networks. Background Technology

[0002] Distribution networks play a crucial role in delivering electricity to the final energy consumers of the power system. However, low impedance ratios and the radial nature of distribution networks lead to significant active power losses as heat. Short-time-scale network configuration (STNC) is one possible solution to minimize active power losses while ensuring reliable system operation. There are two types of switches in distribution networks: normally closed sectionalizing switches and normally open connecting switches. STNC proposes a new distribution network topology by modifying the on / off states of switches in the network.

[0003] Currently, existing methods for solving the Short-Term Network Planning (STNC) problem can be broadly categorized into three types: evolutionary algorithms, mathematical programming, and heuristic methods. However, due to the high computational demands of evolutionary algorithms and mathematical programming, researchers tend to favor heuristic methods for solving the STNC problem. For fast planning, heuristic algorithms consider two strategies: branch switching strategy and sequential switch activation strategy.

[0004] Existing power distribution network planning methods, while achieving optimal results, involve extremely long computation times. Summary of the Invention

[0005] In view of this, the present invention provides a method, medium and system for ultra-short time scale planning of radial distribution networks, which can solve the technical problem that existing distribution network planning methods, although they can obtain optimal results, have very large computation time.

[0006] This invention is implemented as follows:

[0007] The first aspect of the present invention provides a method for ultra-short time-scale planning of radial distribution networks, comprising the following steps:

[0008] S10. Establish a simulated radial power distribution network, including multiple network loops, wherein all branches in the simulated radial power distribution network are equipped with line switches.

[0009] S20. Set the status of all line switches in the simulated radial power distribution network to "on".

[0010] S30. Calculate the current flowing through each circuit switch and record it as the switch current;

[0011] S40. Select the line switch that carries the minimum current in each network loop, change its state from open to closed, and use the line switch that is currently closed as the first switch set.

[0012] S50. Select a line switch from the first switch set, and in the network loop where the selected line switch is located, select any line switch not from the first switch set to form a switch pair, and exchange the states of the switch pair.

[0013] S60. Calculate the branch current and total power loss in the simulated radial distribution network, select the line switch that causes the maximum reduction in power loss as the target switch, exchange it with the line switch selected in step S50, and update the first switch set.

[0014] S70. Repeat steps S50 to S60 until no line switch pair can be found that can further reduce the total power loss. Finally, the optimized line switch configuration is determined and output to the operation and maintenance personnel for planning and adjustment of the radial distribution network.

[0015] The above scheme achieves the following effect: First, the line switch carrying the minimum current in each network loop is closed as the first stage. Then, the line switches carrying the minimum current in each network loop are swapped as the second stage. By adopting this two-stage heuristic algorithm, the planning of radial distribution networks can be solved in a shorter time.

[0016] Based on the above technical solution, the ultra-short time scale planning method for radial distribution networks of the present invention can be further improved as follows:

[0017] The specific steps for establishing a simulated radial distribution network are as follows: Collect geographic information data of the target distribution area, including tower locations, line routes, and user locations; collect distribution network connection topology data and electrical parameter data, including transformer parameters, line parameters, and load parameters; import the collected data into a computer to establish a mathematical model of the simulated radial distribution network; set the power supply mode of the distribution network, determine the power supply points of the distribution network, and set line parameters, transformer parameters, and load parameters; run modeling software to generate the electrical connection topology of the simulated radial distribution network and calculate the electrical parameters.

[0018] Furthermore, the specific steps for setting the state of all line switches in the simulated radial power distribution network to "on" are as follows: initialize the power distribution network line switch state vector; traverse the state vector and set the state of each line switch to "on"; update the power distribution network topology and set the nodes at both ends of the line switch to be electrically connected; call the topology analysis module to recalculate and update the power distribution network current distribution.

[0019] Furthermore, the specific steps for calculating the current flowing through each line switch are as follows: calling the load flow calculation module of the distribution network, constructing an electrical network calculation model based on the distribution network topology, line parameters and load conditions; solving the network electrical balance equation to calculate the current value of each branch; and statistically outputting the branch current information corresponding to each line switch.

[0020] Furthermore, the step of selecting the line switch carrying the minimum current in each network loop specifically involves: sorting and analyzing the calculated branch current information; identifying all network loops in the power distribution network that form a circuit; and selecting the line switch carrying the minimum current in each network loop.

[0021] Furthermore, the step of selecting a line switch from the first set of switches, and randomly selecting a line switch from outside the first set of switches in the network loop where the selected line switch is located to form a switch pair, and exchanging the states of the switch pair, specifically involves: randomly selecting a line switch from the first set of switches; updating the state of the selected line switch to "on"; searching the network loop where the line switch is located, randomly selecting a line switch from outside the first set of switches; and updating the state of the selected line switch to "off".

[0022] Furthermore, the repeated execution of steps S50 to S60 is performed in parallel, specifically:

[0023] S71. For each network loop, execute steps S50 and S60 to obtain the updated first switch set and the corresponding total power loss. The updated first switch set is denoted as the second switch set, and the corresponding total power loss is denoted as the second power loss.

[0024] S72, execute S71 in parallel, and obtain multiple sets of second switches and corresponding second power losses for each parallel execution of S71;

[0025] S73. Select the second switch set with the lowest second power loss in S72 and denote it as the third switch set, and denote the corresponding second power loss as the third power loss.

[0026] S74. Traverse each line switch in the third switch set, and take the line switches in the network loop where the current line switch is located as the exchangeable set, where the current switch current is greater than the current line switch.

[0027] S75. Exchange the states of the currently traversed line switches with the line switches in the exchangeable set.

[0028] S76. Repeat steps S74 to S75 until no line switch pair can be found that can further reduce the total power loss. Finally, the optimized line switch configuration is determined and output to the operation and maintenance personnel for planning and adjustment of the radial distribution network.

[0029] The improvement is that by performing a single switch state exchange in parallel, multiple updated switch sets are obtained. The set with the lowest total power loss is selected for exchange, effectively reducing the number of executions and further decreasing the planning time. Although this parallel processing method cannot achieve the optimal result, it is very close and can be used as a target planning approach.

[0030] A second aspect of the present invention provides a computer-readable storage medium storing program instructions that, when executed, perform the above-described method for ultra-short time-scale planning of a radial distribution network.

[0031] A third aspect of the present invention provides an ultra-short timescale planning system for radial distribution networks, wherein the system includes the aforementioned computer-readable storage medium.

[0032] Compared with existing technologies, the beneficial effects of the radial distribution network ultra-short time-scale planning method, medium, and system provided by this invention are as follows: First, the line switch carrying the minimum current in each network loop is identified and closed as the first stage. Then, the line switches carrying the minimum current in each network loop are exchanged as the second stage. Using this two-stage heuristic algorithm, the radial distribution network planning can be solved in a shorter time. Parallel switching is performed once to obtain multiple updated switch sets. The set with the lowest total power loss is selected for switching, effectively reducing the number of executions and further reducing the planning time. The technical solution of this invention solves the problem that some distribution network planning methods, while achieving optimal results, have very high computation times. Attached Figure Description

[0033] To more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings used in the description of the embodiments of the present invention will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0034] Figure 1 A flowchart of the method provided by the present invention;

[0035] Figure 2 This is a flowchart of the parallel repeating steps in the second embodiment of the present invention;

[0036] Figure 3 This is a schematic diagram of a 33-node test system;

[0037] Figure 4This is a schematic diagram of a 417-node test system. Detailed Implementation

[0038] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings.

[0039] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this invention, "a plurality of" means two or more, unless otherwise explicitly specified.

[0040] like Figure 1 The diagram shown is a flowchart of an ultra-short time-scale planning method for radial distribution networks provided by the first aspect of the present invention. The present invention includes the following steps:

[0041] S10. Establish a simulated radial power distribution network, including multiple network loops, wherein all branches in the simulated radial power distribution network are equipped with line switches;

[0042] S20. Set the status of all line switches in the simulated radial power distribution network to "on".

[0043] S30. Calculate the current flowing through each circuit switch and record it as the switch current;

[0044] S40. Select the line switch that carries the minimum current in each network loop, change its state from open to closed, and use the line switch that is currently closed as the first switch set.

[0045] S50. Select a line switch from the first switch set. In the network loop where the selected line switch is located, select any line switch that is not from the first switch set to form a switch pair. Exchange the states of the switch pair.

[0046] S60. Calculate the branch current and total power loss in the simulated radial distribution network, select the line switch that causes the maximum reduction in power loss as the target switch, exchange it with the line switch selected in step S50, and update the first switch set.

[0047] S70. Repeat steps S50 to S60 until no line switch pair can be found that can further reduce the total power loss. Finally, the optimized line switch configuration is determined and output to the operation and maintenance personnel for planning and adjustment of the radial distribution network.

[0048] The specific implementation methods of the above steps are described below:

[0049] For S10, the specific process of establishing a simulated radial power distribution network is as follows:

[0050] 1) Collect geographic information data of the target power distribution area, including data such as pole and tower locations, line routes, and user locations;

[0051] 2) Collect connection topology data and electrical parameter data of the power distribution network, including transformer parameters, line parameters, load parameters, etc.

[0052] 3) Import the collected geographic information data, topology data, and electrical parameter data into the computer, and use power system modeling software to establish a mathematical model simulating the radial distribution network;

[0053] 4) In the modeling software, set the power supply method of the power distribution network, determine the power supply points of the power distribution network, and set the line parameters, transformer parameters, and load parameters;

[0054] 5) Run the modeling software to generate the electrical connection topology of the simulated radial power distribution network, calculate the electrical parameters, and finally establish a complete simulated radial power distribution network.

[0055] Through the above process, the simulated radial distribution network established can accurately reflect the topology and electrical characteristics of the actual distribution network, providing a basis for subsequent network calculations and planning.

[0056] The specific process of S20 is as follows:

[0057] 1) Initialize the state vectors of all line switches in the simulated radial distribution network;

[0058] 2) Traverse the state vector and set the state of each line switch to the on state;

[0059] 3) Update the topology of the simulated radial distribution network and set the two ends of all line switches to be electrically connected;

[0060] 4) Call the topology analysis module of the power system modeling software to recalculate and update the current distribution in the simulated radial distribution network.

[0061] The above process ensures that all line switches in the simulated radial distribution network are in the conducting state, providing a basis for subsequent current calculations.

[0062] The specific process of S30 is as follows:

[0063] 1) Call the load flow calculation module of the power system modeling software;

[0064] 2) Based on the topology, line parameters, and load conditions of the simulated radial distribution network, construct an electrical network calculation model;

[0065] 3) Solve the network electrical balance equations and calculate the current value of each branch;

[0066] 4) Statistically analyze and output the current information of the corresponding branch of each line switch.

[0067] Based on mathematical models and calculation methods, the current distribution of each branch in the simulated radial distribution network is accurately calculated, providing a basis for subsequent optimization selection of line switches.

[0068] The specific process of S40 is as follows:

[0069] 1) Sort and analyze the calculated branch current information;

[0070] 2) Identify all network loops forming a loop in the simulated radial distribution network;

[0071] 3) Within each identified network loop, select the line switch with the lowest current carrying capacity;

[0072] 4) Update the status of all selected line switches to the off state;

[0073] 5) Form the first set of switches as the initial solution for line switch optimization.

[0074] By selecting the line switch with the lowest current carrying capacity to disconnect the network loop, a better initial switching scheme is formed, providing a basis for further optimization.

[0075] The specific process of S50 is as follows:

[0076] 1) Randomly select a circuit switch from the first set of switches;

[0077] 2) Update the status of the circuit switch to "on";

[0078] 3) Locate the network loop where the line switch is located, and randomly select a line switch that is not in the first set of switches;

[0079] 4) Update the status of the line switches that are not in the first switch set to closed.

[0080] By swapping the line switches in the first switch set, a new line switch switching scheme is formed, providing different switching options for subsequent scheme optimization.

[0081] The specific process of S60 is as follows:

[0082] 1) Call the load flow calculation module of the power system modeling software;

[0083] 2) Reconstruct the distribution network calculation model based on the updated line switch status and topology;

[0084] 3) Solve the distribution network electrical balance equations again to calculate the current and power loss of each branch;

[0085] 4) Calculate the total power loss and compare it with the solution given in S40;

[0086] 5) If the total power loss is reduced, the new solution given by S50 is determined to be better; otherwise, the old solution of S40 is retained.

[0087] Through mathematical modeling and calculation, the advantages and disadvantages of new and old circuit switching schemes are quantitatively analyzed, providing a basis for optimizing the selection of schemes.

[0088] The following is a first embodiment of the method of the present invention:

[0089] A. Phase One: Sequential Switch Opening Strategy

[0090] The first stage involves opening all the line switches in the system, forming a ring network structure. The traditional Newton-Raphson-Lawrence (LAF) method is then used to calculate the current flowing through each line switch. Next, the line switch carrying the minimum current in each network loop is selected, and its state is changed from on to off. Algorithm 1 provides a detailed process for the sequential switch opening strategy.

[0091]

[0092]

[0093] Phase B: Branch Exchange Strategy

[0094] The line switch configuration of the radial network obtained from the first-stage operation is used as the input configuration for the second-stage operation. The tributary switching strategy aims to further reduce the total loss in the network by switching the on / off states of line switches in pairs.

[0095] In a radial network, closing a circuit switch will result in the formation of a network loop. Assuming that circuit switch k1 in the initial network is closed, and circuit switch k2 in the generated loop is opened, a new radial network structure can be obtained. The switching of circuit switches in the network loop can be mathematically modeled as follows:

[0096]

[0097]

[0098] Where BIBC is the matrix of the bus injected branch currents of the radial network before the switching operation is performed; m1 and n1 are the buses connected by line switch k1.

[0099] Let set Ω2 be a subset of Ω1. Ω2 contains the line switches of the new network structure that do not exist on the shortest path connecting buses m1 and n1 to the substation. Mathematically, it can be represented using the BIBC matrix of the initial network as follows:

[0100]

[0101]

[0102] Assuming the current injection into each bus remains unchanged after the exchange operation, Kirchhoff's current law can be used to derive the following conclusions about the branch currents of the new radial network:

[0103] The current flowing through switch k1 in the new network will be equal to the current flowing through switch k2 in the initial network, that is...

[0104]

[0105] If switch k is located within the network loop, then the current in branch k of the new network can be expressed as:

[0106]

[0107] If switch k is outside the network loop, the current in branch k of the new network will not change, that is:

[0108]

[0109] Combining equations (13)-(15), the branch current I' of the new radial network k It can be written in the following simple form:

[0110]

[0111] In the second phase of execution, Equation (17) is used to calculate the impact of the state transition of each pair of line switches in the network on the system power loss, and the pair of line switches that causes the largest change in power loss is selected and their open / closed states are swapped.

[0112]

[0113] After exchanging the on / off states of the selected line switch pairs, the LFA method is executed to check for any constraint violations. This process continues until power loss is reduced and all constraints are satisfied. Algorithm 2 provides a detailed strategy for exchanging the on / off states between line switch pairs.

[0114]

[0115]

[0116] The following is a second embodiment of the present invention. The difference between this embodiment and the previous embodiment is that steps S50 to S60 are repeated in a parallel manner, as follows: Figure 2 As shown, specifically:

[0117] S71. For each network loop, execute steps S50 and S60 to obtain the updated first switch set and the corresponding total power loss. The updated first switch set is denoted as the second switch set, and the corresponding total power loss is denoted as the second power loss.

[0118] S72, execute S71 in parallel, and obtain multiple sets of second switches and corresponding second power losses for each parallel execution of S71;

[0119] S73. Select the second switch set with the lowest second power loss in S72 and denote it as the third switch set, and denote the corresponding second power loss as the third power loss.

[0120] S74. Traverse each line switch in the third switch set, and take the line switches in the network loop where the current line switch is located as the commutable set if the current switch current is greater than the current line switch.

[0121] S75. Exchange the state of the currently traversed line switches with the line switches in the exchangeable set.

[0122] S76. Repeat steps S74 to S75 until no line switch pair can be found that can further reduce the total power loss. Finally, the optimized line switch configuration is determined and output to the operation and maintenance personnel for planning and adjustment of the radial distribution network.

[0123] The following is a detailed description of the second embodiment. For ease of description, the formulas and variables in this embodiment are independent of those in the previous embodiment:

[0124] S10 Specific steps for establishing a simulated radial power distribution network

[0125] First, it is necessary to collect geographic information data of the target power distribution area, including:

[0126] P-Tower location coordinate dataset, P = {p1, p2, ..., p...} N}, where p i Represents the coordinates of the i-th tower.

[0127] L-path routing dataset, L = {(l1, w1), ..., (l...} M w M )}, where l i w represents the length of the i-th line. i Indicates line width

[0128] C-User location coordinate dataset, C = {c1, c2, ..., c...} K}, where c J Represents the coordinates of the j-th user

[0129] Collect connection topology data and electrical parameter data of the power distribution network:

[0130] T-topological matrix, T N×n element t ij Indicates the connection state between node i and node j.

[0131] Z-line impedance parameter matrix, Z N×N element z ij This represents the impedance value from line i to j.

[0132] Y-circuit conductance parameter matrix, Y N×N element y ij This represents the conductance value from line i to line j.

[0133] X-Transformer parameter matrix, X N×N element x ij Represents the transformer parameters from node i to node j.

[0134] D-load demand matrix, D N×N element d ij This represents the load demand value of node i on node j.

[0135] Import the above data into a computer to build a mathematical model:

[0136] f(P, L, C, T, Z, Y, X, D) = F

[0137] Where F represents the mathematical model of the radial power distribution network.

[0138] Configure the power supply method and parameters for the power distribution network:

[0139] Determine the power supply point s

[0140] Set line parameters: l i w i

[0141] Set transformer parameters: x ij

[0142] Set load parameters: d ij

[0143] Run the modeling software to generate a power distribution network model:

[0144]

[0145] in, This represents the mathematical model of the simulated radial power distribution network, and finally outputs the topology diagram and electrical parameter matrix of the simulated radial power distribution network.

[0146] Specific steps for setting all line switches to "on" in S20

[0147] Initialize the line switch state vector:

[0148] S0={s 01 s 02 , ..., s 0i , ..., s ON}

[0149] Among them, s 0i =0 indicates that the initial state of line switch i is closed, and N is the total number of line switches.

[0150] Update the status of the line switch:

[0151] S = {s1, s2, ..., s} i , ..., s N}, s i =1, i = 1, 2, ..., N

[0152] Update the power distribution network topology:

[0153]

[0154] in, This represents the updated mathematical model of the simulated radial power distribution network.

[0155] Call the topology analysis module to calculate current distribution:

[0156]

[0157] Where I represents the current distribution in the updated power distribution network.

[0158] Specific steps for calculating the current in each branch of S30

[0159] Call the load flow calculation module:

[0160]

[0161] Constructing a computational model of the electrical network:

[0162]

[0163] Where R, X, Y are the line impedance parameter matrix, transformer parameter matrix, and line conductance parameter matrix, respectively; U is the voltage parameter matrix; I is the current parameter matrix; and S is the line switch state matrix.

[0164] Solve the current distribution balance equation:

[0165]

[0166] Where P and Q represent active and reactive power respectively, U represents voltage parameters, and I represents current parameters. max This indicates the maximum allowable current of the line.

[0167] The current distribution I is finally solved by using the Newton-Raphson method for successive approximation. Output current distribution:

[0168] I = {I1, I2, ..., I} i , ..., I N}

[0169] Specific steps for selecting the minimum current line switch in S40

[0170] Sorting the branch currents:

[0171] sort(I)

[0172] Identify network loops:

[0173] The Kron Reduction algorithm is used to identify loops in re network.

[0174] Select the circuit switch with the minimum current:

[0175] Within each loop, select the circuit switch i with the minimum current to form the first switch set K. Close the selected circuit switches:

[0176]

[0177] Where S′ represents the updated line switch status.

[0178] S50 Specific Steps

[0179] Randomly select a switch k∈K:

[0180] Settings k =1:

[0181] Find the loop and select switch j that is not in loop K:

[0182] Settings j =0:

[0183] Specific steps for calculating power loss in S60

[0184] Establish an updated power distribution network model

[0185] Solve for the power loss P_loss:

[0186]

[0187] Calculate the total power loss $P$_\text{sum}$

[0188] Comparing the losses between the old and new solutions:

[0189]

[0190] The specific steps of S71 are as follows:

[0191] For each network loop k in the power distribution network:

[0192] (1) Execute S50, that is, select line switch i in the first switch set and exchange it with line switch j in loop k that is not in the first switch set:

[0193] s i =1,s j =0

[0194] (2) Execute S60, that is, calculate the total power loss P′ based on the new switching scheme. sum_k :

[0195]

[0196] (3) Update the second switch set K′ and the second power loss P″:

[0197] K′=K-{i}+{j}

[0198] P″=min(P′ sum ,P sum )

[0199] The specific steps of S72 are as follows:

[0200] K″={K′1,K′2,...,K′ n}

[0201] P″={P″1,P″2,...,P″ n}

[0202] That is, S71 is executed in parallel to obtain multiple sets of second switches K″ and power loss P″.

[0203] The specific steps of S73 are as follows:

[0204]

[0205]

[0206] That is, select the one with the minimum power loss P″ (P * Corresponding to the second switch set K * As the third set of switches.

[0207] The specific steps of S74 are as follows:

[0208] For the third switch set K * For each switch i in the loop, find all switches with current greater than i to form a commutative set S. i .

[0209] The specific steps of S75 are as follows:

[0210] Select switch i and its exchangeable set S i Switch j in the middle performs state exchange:

[0211] s i =0,s j =1

[0212] The specific steps of S76 are as follows:

[0213] Repeat the switching and power loss calculations in S74 and S75 until the loss can no longer be reduced, then output the current optimal switch set.

[0214] A second aspect of the present invention provides a computer-readable storage medium storing program instructions that, when executed, perform the above-described method for ultra-short time-scale planning of a radial distribution network.

[0215] A third aspect of the present invention provides an ultra-short timescale planning system for radial distribution networks, wherein the system includes the aforementioned computer-readable storage medium.

[0216] The superiority of the proposed radial distribution network short-run planning method is verified using five test cases with varying node sizes: 33 nodes, 69 nodes, 84 nodes, 136 nodes, and 417 nodes. (Specific test system data can be downloaded from the website: https: / / www.feis.unesp.br / #! / departamentos / engenharia-eletrica / pesquisas-e-projetos / lapsee / downloads / materiais-de-cursos1193 / )

[0217] A brief explanation is as follows:

[0218] like Figure 3As shown, the 33-node test system is a hypothetical 12.66kV radial distribution network with 5 connection switches (open circuit switches). The initial actual power loss is approximately 5.7% of the total active power load, or 211.0kW.

[0219] The 69-node test system is a hypothetical 12.66kV radial distribution network with 69 nodes and 5 loops. The active and reactive system loads are 3802.19kW and 2694.60kVar, respectively, with an initial actual power loss of 225.0kW.

[0220] The 136-node test system is a real 13.8kV distribution system with 136 nodes and 156 lines. With a total load of 18313.8kW and 7932.5kVar, the initial actual power loss is 320.36kW. To demonstrate the impact of photovoltaic (PV) output on short-term distribution network planning, three PV installation scenarios were added to the 136-node system, as shown in Table 1, with a power factor set to 0.90. The PV installation penetration rates for the three scenarios are 12.56%, 20.20%, and 30.03%, respectively.

[0221] Table 1. Three scenarios for photovoltaic installation in a 136-node system.

[0222]

[0223] The scale of the 417-node test system is as follows: Figure 4 As shown, there is a radial network with 125 switches.

[0224] Since different testing environments and hardware have a significant impact on computational efficiency, it is first stated that the simulation platform of the proposed method is MATLAB (R2022b), and the test hardware configuration is a 64-bit system with an Intel Core i7-12700F, 2.10GHz CPU, and 32GB RAM.

[0225] Table 2 shows the list of connected switches obtained by the proposed method after short-term distribution network planning in a single hour.

[0226] Table 2 Results of Short-Term Distribution Network Planning Switches for 5 Systems Not Required for Testing

[0227]

[0228] To demonstrate the effectiveness of the proposed method, we also simulated and compared two popular heuristic short-term distribution network planning methods—the PM method (published in 2012) and the SOE method (published in 2020)—under the same operating environment. Table 3 lists the comparison results for five systems of different scales. The benchmark for network loss in the optimal configuration test system was obtained from existing work by exhaustively enumerating all possible optimal results.

[0229] Table 3 Comparison of results between the method proposed in the patent and advanced short-term distribution network planning algorithms.

[0230]

[0231]

[0232] As can be seen from Table 3, we can draw the following conclusions:

[0233] For test systems with 33, 69, 84, and 136 nodes, the proposed short-term distribution network planning method achieves 100% accuracy in minimizing lossy networks. Furthermore, in larger systems, such as the 417 bus test system, the accuracy of the proposed method decreases by only 0.29%.

[0234] The SOE and PM methods achieved optimal solutions in 33-node and 69-node systems, but the results were slightly worse in 84-node, 136-node, and 417-node systems. However, in the 417-node system, SOE achieved the best results, with a 0.05% improvement in solution quality compared to the method proposed in this patent, while its computational speed was 1451 times faster.

[0235] Comparative analysis also confirms that the proposed methodology is currently the fastest heuristic method for short-term distribution network planning in radial distribution networks. It is 2-1450 times faster than other algorithms across all problems, with its computational efficiency becoming more pronounced in systems with larger nodes.

[0236] The improvement in computational efficiency is mainly due to the reduction in the number of power flow analyses performed during operation. In the proposed Phase 1: sequential switch-opening strategy, the optimal current is not considered, thus eliminating the requirement to perform power flow analysis after each line switch is opened, thereby reducing computation time. The proposed Phase 2: line switching strategy further ensures the distribution network configuration with the lowest active power loss.

[0237] Next, we demonstrate how the proposed method iteratively reaches the optimal solution in each test system. As shown in the figure, the optimal solution is obtained within ten iterations in the 33-136 node system, while the 417 node system requires only 27 iterations. Table 4 shows the network loss at different stages for each test system.

[0238] Table 4 Active power losses (kW) at different operating stages

[0239]

[0240]

[0241] The above description is merely a specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in the present invention should be included 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 method for ultra-short time-scale planning of radial distribution networks, characterized in that, Includes the following steps: S10. Establish a simulated radial power distribution network, including multiple network loops, wherein all branches in the simulated radial power distribution network are equipped with line switches. S20. Set the status of all line switches in the simulated radial power distribution network to "on". S30. Calculate the current flowing through each circuit switch and record it as the switch current; S40. Select the line switch that carries the minimum current in each network loop, change its state from open to closed, and use the line switch that is currently closed as the first switch set. S50. Select a line switch from the first switch set, and in the network loop where the selected line switch is located, select any line switch not from the first switch set to form a switch pair, and exchange the states of the switch pair. S60. Calculate the branch current and total power loss in the simulated radial distribution network, select the line switch that causes the maximum reduction in power loss as the target switch, exchange it with the line switch selected in step S50, and update the first switch set. S70. Repeat steps S50 to S60 until no line switch pair can be found that can further reduce the total power loss. Finally, the optimized line switch configuration is determined and output to the operation and maintenance personnel for planning and adjustment of the radial distribution network. The repeated execution of steps S50~S60 is performed in parallel repetition, specifically: S71. For each network loop, execute steps S50 and S60 to obtain the updated first switch set and the corresponding total power loss. The updated first switch set is denoted as the second switch set, and the corresponding total power loss is denoted as the second power loss. S72, execute S71 in parallel, and obtain multiple sets of second switches and corresponding second power losses for each parallel execution of S71; S73. Select the second switch set with the lowest second power loss in S72 and denote it as the third switch set, and denote the corresponding second power loss as the third power loss. S74. Traverse each line switch in the third switch set, and take the line switches in the network loop where the current line switch is located as the exchangeable set, where the current switch current is greater than the current line switch. S75. Exchange the states of the currently traversed line switches with the line switches in the exchangeable set. S76. Repeat steps S74 to S75 until no line switch pair can be found that can further reduce the total power loss. Finally, the optimized line switch configuration is determined and output to the operation and maintenance personnel for planning and adjustment of the radial distribution network.

2. The ultra-short time scale planning method for radial distribution networks according to claim 1, characterized in that, The specific steps for establishing a simulated radial distribution network are as follows: Collect geographic information data of the target distribution area, including tower locations, line routes, and user locations; collect distribution network connection topology data and electrical parameter data, including transformer parameters, line parameters, and load parameters; import the collected data into a computer to establish a mathematical model of the simulated radial distribution network; set the power supply mode of the distribution network, determine the power supply points of the distribution network, and set line parameters, transformer parameters, and load parameters; run the modeling software to generate the electrical connection topology of the simulated radial distribution network and calculate the electrical parameters.

3. The ultra-short time scale planning method for radial distribution networks according to claim 2, characterized in that, The specific steps for setting the state of all line switches in the simulated radial power distribution network to "on" are as follows: initialize the power distribution network line switch state vector; traverse the state vector and set the state of each line switch to "on"; update the power distribution network topology and set the nodes at both ends of the line switch to be electrically connected; call the topology analysis module to recalculate and update the current distribution of the power distribution network.

4. The ultra-short time scale planning method for radial distribution networks according to claim 3, characterized in that, The specific steps for calculating the current flowing through each line switch are as follows: call the load flow calculation module of the distribution network, construct an electrical network calculation model based on the distribution network topology, line parameters and load conditions; solve the network electrical balance equation to calculate the current value of each branch; and statistically output the branch current information corresponding to each line switch.

5. The ultra-short time scale planning method for radial distribution networks according to claim 4, characterized in that, The step of selecting the line switch with the minimum current carrying capacity in each network loop specifically involves: sorting and analyzing the calculated branch current information; identifying all network loops in the power distribution network that form a circuit; and selecting the line switch with the minimum current carrying capacity in each network loop.

6. The ultra-short time scale planning method for radial distribution networks according to claim 5, characterized in that, The steps of selecting a line switch from the first set of switches, and randomly selecting a line switch from outside the first set of switches in the network loop where the selected line switch is located to form a switch pair, and exchanging the states of the switch pair, are as follows: randomly select a line switch from the first set of switches; update the state of the line switch to "on"; search the network loop where the line switch is located, and randomly select a line switch from outside the first set of switches. Update the selected line switch status to closed.

7. A computer-readable storage medium, characterized in that, The computer-readable storage medium stores program instructions, which, when executed, are used to perform an ultra-short time-scale planning method for radial distribution networks as described in any one of claims 1-6.

8. A radial distribution network ultra-short time-scale planning system, characterized in that, It includes the computer-readable storage medium of claim 7.

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