A method and device for post-disaster emergency repair scheduling of a distribution network based on a combination of greedy algorithms

Abstract

The present invention relates to a post-disaster emergency repair scheduling method for a distribution network based on a combination of greedy algorithms, comprising the following steps: constructing greedy algorithms for three preventive emergency repair strategies, respectively seeking optimal solutions according to the load state of the distribution network at that time, and selecting the optimal solution with the smallest loss of the distribution network as the emergency repair strategy for the distribution network; each greedy algorithm includes: starting from the emergency repair center, each emergency repair team respectively selects the fault point that best meets the corresponding emergency repair strategy for emergency repair. After each emergency repair team finishes the emergency repair, it selects the fault point that has not been repaired and best meets the corresponding emergency repair strategy for emergency repair until all faults are repaired; the emergency repair strategies corresponding to the three greedy algorithms are the closest distance, the best emergency repair effect, and the highest emergency repair efficiency. Compared with the prior art, the present invention can quickly obtain a satisfactory solution, save a large amount of time consumed in exploring the entire space, and improve the efficiency of post-disaster solution while ensuring optimality as much as possible.

Description

Technical Field

[0001] The present invention relates to the field of distribution networks, and in particular, to a method and device for post-disaster emergency repair scheduling of distribution networks based on a combination of greedy algorithms. Background Art

[0002] When the distribution network is in a disaster scenario, disaster losses will be formed, affecting the normal operation of the distribution network. Therefore, for each disaster scenario selected by nature, post-disaster distribution network reconstruction needs to be carried out under this scenario, and for the load that cannot be restored by the reconstruction, emergency repair personnel need to be arranged for emergency repair until the distribution network resumes normal operation. The goal of post-disaster reconstruction and emergency repair is to find the optimal solution to the emergency repair problem and reduce power grid losses.

[0003] Most of the existing distribution network emergency repair strategies currently solve optimization problems through algorithms such as particle swarm algorithms to seek the optimal solution. However, the solution efficiency of particle swarms is relatively low, especially when the number of particles increases, the particle dimension increases, or the number of iterations becomes large. And post-disaster emergency repair, as a time-critical stage, requires it to have a relatively high solution efficiency. Therefore, it is necessary to seek a more efficient post-disaster emergency repair algorithm. Summary of the Invention

[0004] The purpose of the present invention is to overcome the above-mentioned defects existing in the prior art and provide a more efficient method and device for post-disaster emergency repair scheduling of distribution networks based on a combination of greedy algorithms.

[0005] The purpose of the present invention can be achieved by the following technical solutions:

[0006] A method for post-disaster emergency repair scheduling of distribution networks based on a combination of greedy algorithms includes the following steps:

[0007] Construct three greedy algorithms for preventive emergency repair strategies, and respectively seek the optimal solution according to the load state of the distribution network at that time, and select the optimal solution with the smallest loss of the distribution network as the emergency repair strategy of the distribution network;

[0008] The three greedy algorithms for preventive emergency repair strategies include:

[0009] Distance-based greedy algorithm: Starting from the emergency repair center, each emergency repair team respectively selects the fault point closest to the emergency repair center for emergency repair. After each emergency repair team finishes the emergency repair, select the fault point that has not been repaired and is closest to the emergency repair team for emergency repair until all faults are repaired;

[0010] Greedy algorithm based on emergency repair effect: Define the emergency repair effect of the fault points in the distribution network in advance. Starting from the emergency repair center, each emergency repair team respectively selects the fault point with the largest emergency repair effect for emergency repair. After each emergency repair team finishes the emergency repair, select the fault point with the largest emergency repair effect among the fault points that have not been repaired for emergency repair until all faults are repaired;

[0011] Greedy algorithm based on emergency repair efficiency: The emergency repair efficiency of the fault points in the distribution network is predefined. Starting from the emergency repair center, each emergency repair team selects the fault point with the highest emergency repair efficiency for repair respectively. After each emergency repair team finishes the repair, it selects the fault point with the highest emergency repair efficiency among the fault points that have not been repaired until all the faults are repaired.

[0012] Furthermore, the value of the load picked up by the distribution network system after repairing a fault point is defined as the emergency repair effect of this fault point.

[0013] Furthermore, if after repairing a fault point, the island microgrid M m is connected to the distribution network feeder, the expression of the emergency repair effect of this fault point is:

[0014]

[0015] In the formula, i is the load serial number in the island microgrid M m , p i is the output power corresponding to the load i, and w i is the weight corresponding to the load i.

[0016] Furthermore, the greedy algorithm based on the emergency repair effect further includes: if there are multiple fault points and the emergency repair effects of the repairs are the same, the greedy algorithm based on the distance is used to determine the emergency repair strategy.

[0017] Furthermore, the emergency repair efficiency is calculated according to the emergency repair time of a certain fault point, and the emergency repair time of a certain fault point is: the time from when an emergency repair team departs from its location to when the fault point is repaired, that is, the sum of the road time and the fault repair time.

[0018] Furthermore, if after repairing a fault point, the island microgrid M m is connected to the distribution network feeder and the emergency repair time of this fault point is T r , then the emergency repair efficiency of this fault point for this emergency repair team is:

[0019]

[0020] In the formula, i is the load serial number in the island microgrid M m , p i is the output power corresponding to the load i, and w i is the weight corresponding to the load i.

[0021] Furthermore, the greedy algorithm based on the emergency repair efficiency further includes: if there are multiple fault points and the emergency repair efficiencies of the repairs are the same, the greedy algorithm based on the distance is used to determine the emergency repair strategy.

[0022] The present invention also provides a post-disaster emergency repair scheduling device for a distribution network based on a greedy algorithm combination, including:

[0023] A distance-based greedy algorithm module, configured to, according to the load state of the distribution network at that time, starting from the emergency repair center, each emergency repair team respectively selects the fault point closest to the emergency repair center for emergency repair. After each emergency repair team finishes the emergency repair, it selects the fault point that has not been repaired and is closest to the emergency repair team for emergency repair until all faults are repaired, obtaining the first optimal solution;

[0024] A greedy algorithm module based on emergency repair effect, configured to pre-define the emergency repair effect of the fault points in the distribution network. According to the load state of the distribution network at that time, starting from the emergency repair center, each emergency repair team respectively selects the fault point with the maximum emergency repair effect for emergency repair. After each emergency repair team finishes the emergency repair, it selects the fault point with the maximum emergency repair effect among the fault points that have not been repaired for emergency repair until all faults are repaired, obtaining the second optimal solution;

[0025] A greedy algorithm module based on emergency repair efficiency, configured to pre-define the emergency repair efficiency of the fault points in the distribution network. According to the load state of the distribution network at that time, starting from the emergency repair center, each emergency repair team respectively selects the fault point with the highest emergency repair efficiency for emergency repair. After each emergency repair team finishes the emergency repair, it selects the fault point with the highest emergency repair efficiency among the fault points that have not been repaired for emergency repair until all faults are repaired, obtaining the third optimal solution;

[0026] A final emergency repair strategy determination module, configured to obtain the first optimal solution, the second optimal solution, and the third optimal solution, and select the optimal solution with the minimum loss of the distribution network therefrom as the emergency repair strategy of the distribution network.

[0027] Further, the value of the load picked up by the distribution network system after repairing a fault point is defined as the emergency repair effect of the fault point;

[0028] If after repairing a fault point, the island microgrid M m is connected to the distribution network feeder, the expression of the emergency repair effect of the fault point is:

[0029]

[0030] In the formula, i is the load serial number in the island microgrid M m p i is the output power corresponding to the load i, and w i is the weight corresponding to the load i;

[0031] The greedy algorithm based on the emergency repair effect further includes: if there are multiple fault points and the repaired emergency repair effects are the same, the distance-based greedy algorithm is used to determine the emergency repair strategy.

[0032] Further, the emergency repair efficiency is calculated based on the emergency repair time of a certain fault point. The emergency repair time of a certain fault point is the time from when a certain emergency repair team departs from its location to when the fault point is repaired, that is, the sum of the road time and the fault repair time;

[0033] After a fault point is repaired, if the island microgrid M m is connected to the distribution network feeder, the emergency repair time of this fault point is T r , then the emergency repair efficiency of this fault point for this emergency repair team is:

[0034]

[0035] In the formula, i is the load serial number in the island microgrid M m , p i is the output power corresponding to the load i, and w i is the weight corresponding to the load i;

[0036] The greedy algorithm based on the emergency repair efficiency further includes: if there are multiple fault points and the emergency repair efficiencies for repair are the same, then the greedy algorithm based on distance is used to determine the emergency repair strategy.

[0037] Compared with the prior art, the present invention has the following advantages:

[0038] (1) Compared with algorithms such as particle swarm that need to explore the entire strategy space and iteratively optimize, the greedy algorithm can quickly obtain a satisfactory solution. The greedy algorithm often makes an optimal choice based on the current situation without considering the overall situation, so it will save a large amount of time consumed in exploring the entire space; the present invention designs three preventive emergency repair strategies using the greedy algorithm, improving the post-disaster solution efficiency while ensuring optimality as much as possible.

[0039] (2) Generally speaking, no matter what kind of greedy algorithm, it cannot guarantee a relatively satisfactory post-disaster emergency repair effect. However, taking the best one among the three greedy algorithms can often achieve a relatively satisfactory emergency repair effect while maintaining a high emergency repair efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0040] Figure 1 is a schematic flowchart of a method for post-disaster emergency repair scheduling of a distribution network based on a combination of greedy algorithms provided in an embodiment of the present invention. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0041] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention. Apparently, the described embodiments are some, but not all, of the embodiments of the present invention. Components of the embodiments of the present invention generally described and illustrated in the figures herein can be arranged and designed in a variety of different configurations.

[0042] Therefore, the following detailed description of the embodiments of the present invention provided in the drawings is not intended to limit the scope of the claimed invention, but merely represents selected embodiments of the present invention. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts fall within the scope of protection of the present invention.

[0043] It should be noted that like reference numerals and letters denote like items in the following figures. Therefore, once an item is defined in one figure, it does not need to be further defined and explained in subsequent figures.

[0044] Embodiment 1

[0045] As Figure 1 shown, this embodiment provides a post-disaster emergency repair scheduling method for a distribution network based on a combination of greedy algorithms, including the following steps:

[0046] Construct greedy algorithms for three preventive emergency repair strategies, and respectively seek the optimal solutions according to the load status of the distribution network at that time. Select the optimal solution with the minimum loss of the distribution network as the emergency repair strategy of the distribution network;

[0047] The greedy algorithms for the three preventive emergency repair strategies include:

[0048] Distance-based greedy algorithm: Starting from the emergency repair center, each emergency repair team selects the fault point closest to the emergency repair center for emergency repair respectively. After each emergency repair team finishes the emergency repair, select the closest un-repaired fault point to the emergency repair team for emergency repair until all faults are repaired;

[0049] Greedy algorithm based on emergency repair effect: Pre-define the emergency repair effect of the fault points in the distribution network. Starting from the emergency repair center, each emergency repair team selects the fault point with the maximum emergency repair effect for emergency repair respectively. After each emergency repair team finishes the emergency repair, select the fault point with the maximum emergency repair effect among the un-repaired fault points for emergency repair until all faults are repaired;

[0050] Greedy algorithm based on repair efficiency: The repair efficiency of fault points in the distribution network is predefined. Starting from the repair center, each repair team selects the fault point with the highest repair efficiency for repair respectively. After each repair team finishes the repair, it selects the fault point with the highest repair efficiency among the un-repaired fault points for repair until all faults are repaired.

[0051] The detailed description of this method is as follows:

[0052] For a specific disaster scenario, the particle swarm algorithm can approximately solve the post-disaster repair problem of multiple repair teams optimally. However, the solving efficiency of the particle swarm is relatively low, especially when the number of particles increases, the particle dimension increases, or the number of iterations becomes larger. And post-disaster repair, as the last stage of the distribution network disaster resistance game, requires relatively high solving efficiency. Therefore, it is necessary to seek a more efficient post-disaster repair algorithm.

[0053] Compared with algorithms such as particle swarm that need to explore the entire strategy space and iteratively optimize, the greedy algorithm can quickly obtain a satisfactory solution. The greedy algorithm often makes the optimal choice based on the current situation without considering the overall situation, so it can save a large amount of time consumed in exploring the entire space. In this embodiment, three preventive repair strategies are designed using the greedy algorithm to improve the post-disaster solving efficiency while ensuring optimality as much as possible.

[0054] Greedy algorithm based on distance: Starting from the repair center, r repair teams respectively select the r fault points closest to the repair center for repair; after each repair team finishes the repair, it selects the un-repaired fault point closest to it for repair until all faults are repaired.

[0055] Greedy algorithm based on repair effect: First, the repair effect is defined. The value of the load picked up by the system after a fault point is repaired is defined as the repair effect of this fault point. Generally speaking, after a fault point is repaired and the corresponding fault line is restored, there will be an islanded microgrid connected to the distribution network feeder to restore normal power supply. If an islanded microgrid M m is connected to the distribution network feeder, the expression of the repair effect of this fault point is:

[0056]

[0057] In the formula, i is the load serial number in the islanded microgrid M m in, p i is the output power corresponding to load i, and w i is the weight corresponding to load i.

[0058] The greedy algorithm based on the repair effect starts from the repair center, and r repair teams respectively select the r fault points with the greatest repair effect for repair; after each repair team finishes the repair, it selects the fault point with the greatest repair effect among the fault points that have not been repaired until all faults are repaired. If there are multiple fault points with the same repair effect (that is, repairing any one of the fault points can cause a certain load area to resume normal power supply), the greedy algorithm based on distance is adopted.

[0059] The greedy algorithm based on the repair efficiency: On the basis of the greedy algorithm based on the repair effect, the time-consuming of fault point repair is further considered, so as to introduce the concept of repair efficiency. For a certain repair team, the repair time-consuming of a certain fault point is: the time from the position where the repair team is located to the completion of the repair of this fault point, that is, the sum of the road time and the fault repair time. If an island microgrid M m is connected to the distribution network feeder, and the repair time-consuming of this fault point for a repair team is T r , then the repair efficiency of this fault point for this repair team is:

[0060]

[0061] In the formula, i is the load serial number in the island microgrid M m , p i is the output power corresponding to the load i, and w i is the weight corresponding to the load i.

[0062] The greedy algorithm based on the repair efficiency is that r repair teams respectively select the r fault points with the highest repair efficiency for repair; after each repair team finishes the repair, it selects the fault point with the highest repair efficiency among the fault points that have not been repaired until all faults are repaired. If there are multiple fault points with the same repair efficiency, the greedy algorithm based on distance is adopted.

[0063] Generally speaking, no matter which greedy algorithm, it cannot guarantee a satisfactory repair effect after the disaster. However, taking the best one among the three greedy algorithms can often achieve a relatively satisfactory repair effect while maintaining a high repair efficiency.

[0064] Embodiment 2

[0065] This embodiment provides a distribution network post-disaster repair scheduling device based on a combined greedy algorithm, including:

[0066] The distance-based greedy algorithm module is configured to, according to the current load status of the distribution network, starting from the repair center, each repair team selects the fault point closest to the repair center for repair respectively. After each repair team has completed the repair, it selects the closest un-repaired fault point to the repair team for repair until all faults are repaired, obtaining the first optimal solution;

[0067] The repair-effect-based greedy algorithm module is configured to pre-define the repair effect of fault points in the distribution network. According to the current load status of the distribution network, starting from the repair center, each repair team selects the fault point with the maximum repair effect for repair respectively. After each repair team has completed the repair, it selects the fault point with the maximum repair effect among the un-repaired fault points for repair until all faults are repaired, obtaining the second optimal solution;

[0068] The repair-efficiency-based greedy algorithm module is configured to pre-define the repair efficiency of fault points in the distribution network. According to the current load status of the distribution network, starting from the repair center, each repair team selects the fault point with the highest repair efficiency for repair respectively. After each repair team has completed the repair, it selects the fault point with the highest repair efficiency among the un-repaired fault points for repair until all faults are repaired, obtaining the third optimal solution;

[0069] The final repair strategy determination module is configured to obtain the first optimal solution, the second optimal solution, and the third optimal solution, and select the optimal solution with the minimum loss of the distribution network from them as the repair strategy of the distribution network.

[0070] Define the value of the load picked up by the distribution network system after a fault point is repaired as the repair effect of the fault point;

[0071] If after a fault point is repaired, the island microgrid M m is connected to the distribution network feeder, then the expression for the repair effect of the fault point is:

[0072]

[0073] In the formula, i is the load serial number in the island microgrid M m , p i is the output power corresponding to the load i, and w i is the weight corresponding to the load i;

[0074] The repair-effect-based greedy algorithm further includes: if there are multiple fault points and the repair effects of the repairs are the same, then use the distance-based greedy algorithm to determine the repair strategy.

[0075] The emergency repair efficiency is calculated based on the emergency repair time of a certain fault point. The emergency repair time of a certain fault point is the time from when a certain emergency repair team departs from its location to the completion of the repair at the fault point, that is, the sum of the road time and the fault repair time;

[0076] After a fault point is repaired, if the island microgrid M m is connected to the distribution network feeder, the emergency repair time of this fault point is T r , then for this emergency repair team, the emergency repair efficiency of this fault point is:

[0077]

[0078] In the formula, i is the load serial number in the island microgrid M m , p i is the output power corresponding to the load i, and w i is the weight corresponding to the load i;

[0079] The greedy algorithm based on the emergency repair efficiency further includes: if there are multiple fault points and the emergency repair efficiencies for repair are the same, then a distance-based greedy algorithm is used to determine the emergency repair strategy.

[0080] The above has described in detail the preferred specific embodiments of the present invention. It should be understood that those of ordinary skill in the art can make many modifications and variations based on the concept of the present invention without creative labor. Therefore, all technical solutions that can be obtained by those skilled in the art in the technical field of the present invention based on the concept of the present invention through logical analysis, reasoning, or limited experiments on the basis of the prior art should be within the protection scope determined by the claims.

Claims

1. A post-disaster emergency repair scheduling method for distribution networks based on a combination of greedy algorithms, characterized in that, it includes the following steps: Construct greedy algorithms for three preventive emergency repair strategies, and according to the load status of the distribution network at that time, respectively seek the optimal solutions, and select the optimal solution with the smallest loss of the distribution network as the emergency repair strategy of the distribution network; The greedy algorithms for the three preventive emergency repair strategies include: Distance-based greedy algorithm: Starting from the emergency repair center, each emergency repair team selects the fault point closest to the emergency repair center for emergency repair respectively. After each emergency repair team finishes the emergency repair, it selects the closest un-repaired fault point to the emergency repair team for emergency repair until all faults are repaired; Emergency repair effect-based greedy algorithm: Define the emergency repair effect of the fault points in the distribution network in advance. Starting from the emergency repair center, each emergency repair team selects the fault point with the largest emergency repair effect for emergency repair respectively. After each emergency repair team finishes the emergency repair, it selects the fault point with the largest emergency repair effect among the un-repaired fault points for emergency repair until all faults are repaired; Emergency repair efficiency-based greedy algorithm: Define the emergency repair efficiency of the fault points in the distribution network in advance. Starting from the emergency repair center, each emergency repair team selects the fault point with the highest emergency repair efficiency for emergency repair respectively. After each emergency repair team finishes the emergency repair, it selects the fault point with the highest emergency repair efficiency among the un-repaired fault points for emergency repair until all faults are repaired; The emergency repair effect-based greedy algorithm further includes: If there are multiple fault points and the repaired emergency repair effects are the same, then use the distance-based greedy algorithm to determine the emergency repair strategy; The emergency repair efficiency-based greedy algorithm further includes: If there are multiple fault points and the repaired emergency repair efficiencies are the same, then use the distance-based greedy algorithm to determine the emergency repair strategy.

2. The post-disaster emergency repair scheduling method for distribution networks based on a combination of greedy algorithms according to claim 1, characterized in that, Define the value of the load picked up by the distribution network system after repairing a fault point as the emergency repair effect of the fault point.

3. The post-disaster emergency repair scheduling method for distribution networks based on a combination of greedy algorithms according to claim 2, characterized in that, If a fault point is repaired, the islanded microgrid M m is connected to the distribution network feeder, and the expression for the repair effect of this fault point is: where \(i\) is the load number in the islanded microgrid \(M\) m ; \(p\) i is the output power corresponding to load \(i\); \(w\) i is the weight corresponding to load \(i\).

4. The post-disaster emergency repair scheduling method for distribution networks based on a combination of greedy algorithms according to claim 1, characterized in that, The emergency repair efficiency is calculated according to the emergency repair time of a certain fault point, and the emergency repair time of a certain fault point is: the time for an emergency repair team to start from its location to the completion of the repair of the fault point, that is, the sum of the road time and the fault repair time.

5. The post-disaster emergency repair scheduling method for distribution networks based on a combination of greedy algorithms according to claim 4, characterized in that, If a fault point is repaired, the islanded microgrid M m is connected to the distribution network feeder, and the repair time of this fault point is T r , then the repair efficiency of this fault point for this repair team is as follows: Where, i is the load number in the island microgrid M m , p i is the output power corresponding to load i, w i is the weight corresponding to load i.

6. A post-disaster emergency repair scheduling device for distribution networks based on a combination of greedy algorithms, characterized in that, it includes: A distance-based greedy algorithm module, configured to, according to the load status of the distribution network at that time, starting from the emergency repair center, each emergency repair team selects the fault point closest to the emergency repair center for emergency repair respectively. After each emergency repair team finishes the emergency repair, it selects the closest un-repaired fault point to the emergency repair team for emergency repair until all faults are repaired, and obtain the first optimal solution; The greedy algorithm module based on the repair effect is configured to pre-define the repair effect of the fault points in the distribution network. According to the load state of the distribution network at that time, starting from the repair center, each repair team respectively selects the fault point with the maximum repair effect for repair. After each repair team finishes the repair, it selects the fault point with the maximum repair effect among the un-repaired fault points for repair until all faults are repaired, and the second optimal solution is obtained; The greedy algorithm module based on the repair efficiency is configured to pre-define the repair efficiency of the fault points in the distribution network. According to the load state of the distribution network at that time, starting from the repair center, each repair team respectively selects the fault point with the highest repair efficiency for repair. After each repair team finishes the repair, it selects the fault point with the highest repair efficiency among the un-repaired fault points for repair until all faults are repaired, and the third optimal solution is obtained; The final repair strategy determination module is configured to obtain the first optimal solution, the second optimal solution and the third optimal solution, and select the optimal solution with the minimum loss of the distribution network therefrom as the repair strategy of the distribution network; The greedy algorithm based on the repair effect further includes: if there are multiple fault points and the repair effects of the repairs are the same, the greedy algorithm based on the distance is used to determine the repair strategy; The greedy algorithm based on the repair efficiency further includes: if there are multiple fault points and the repair efficiencies of the repairs are the same, the greedy algorithm based on the distance is used to determine the repair strategy.

7. The post-disaster repair scheduling device for a distribution network based on a combination of greedy algorithms according to claim 6, wherein, the value of the load picked up by the distribution network system after repairing a fault point is defined as the repair effect of this fault point; If a fault point is repaired, the islanded microgrid M m is connected to the distribution network feeder, and the expression for the repair effect of this fault point is: where \(i\) is the load number in the islanded microgrid \(M\) m ; \(p\) i is the output power corresponding to load \(i\); \(w\) i is the weight corresponding to load \(i\).

8. The post-disaster repair scheduling device for a distribution network based on a combination of greedy algorithms according to claim 6, wherein, the repair efficiency is calculated according to the repair time of a certain fault point, and the repair time of a certain fault point is: the time from when a certain repair team departs from its location to when the fault point is repaired, that is, the sum of the road time and the fault repair time; If a fault point is repaired, the islanded microgrid M m is connected to the distribution network feeder, and the repair time for this fault point is T r , then the repair efficiency of this fault point for this repair team is as follows: Wherein, i is the load serial number in the island microgrid M m , p i is the output power corresponding to the load i, and w i is the weight corresponding to the load i.

Images