Power distribution network post-fault load recovery method considering minimum duration

Abstract

The invention discloses a power distribution network post-fault load recovery method considering minimum duration, which comprises the following steps of: 1, establishing a target function of a power distribution network post-fault load recovery model by taking maximization of weighted load recovery quantity and maximization of minimum duration of a micro-grid as targets; 2, establishing a power distribution network radial constraint by considering the running radial performance of the power distribution network; 3, considering the minimum duration of the micro-grid, and establishing the minimum duration constraint of the micro-grid; 4, mobile emergency power supply vehicle constraints are established; 5, considering operation safety of the power distribution network, and establishing power flow balance and safe operation constraints of the power distribution network; and 6, solving the power distribution network post-fault load recovery model, and obtaining a power distribution network post-fault load recovery scheme. According to the method, the operation safety of the power distribution network is ensured, the problem of unbalanced power flow is avoided, the minimum duration time of the micro-grid and the mobile emergency power supply vehicle are cooperatively considered, the load recovery method after the power distribution network breaks down is effectively obtained, and the power failure loss is reduced.

Description

Technical Field

[0001] The invention relates to the field of load recovery after a distribution network fault, and in particular to a method for load recovery after a distribution network fault taking into account a minimum duration. Background Art

[0002] In recent years, with the frequent occurrence of natural disasters, the safe and stable operation of distribution networks faces severe challenges. Extreme weather and geological disasters such as typhoons, floods, and earthquakes often lead to large-scale equipment damage, line interruptions, and power outages in distribution networks, seriously affecting the reliability of power supply. In this environment, how to effectively ensure the safe operation of distribution networks and improve post-disaster recovery capabilities has become an important issue that needs to be urgently addressed in the power industry. The impact of natural disasters on distribution networks is mainly reflected in many aspects. First, the equipment damage and line interruptions caused by disasters make it impossible for traditional fault recovery strategies to quickly restore normal power supply. Especially in a wide range of areas, traditional recovery methods often cannot efficiently cope with complex and changeable fault scenarios. Secondly, when the distribution network forms a microgrid, the problem of unbalanced power flow during the load recovery process after the fault becomes a new challenge. In addition, although the mobile emergency power supply vehicle, as a combination of energy storage power supply and traditional diesel generator units, can provide partial support for post-disaster load recovery, its scheduling and resource allocation still face huge technical challenges. How to optimize resource scheduling and load distribution and ensure efficient coordination of various links in the recovery process is one of the difficulties in current research. Therefore, more comprehensive and accurate research is urgently needed to address the problem of load recovery after distribution network failures in order to improve post-disaster recovery efficiency and ensure the stability and reliability of the power system. Summary of the invention

[0003] In order to overcome the shortcomings of the above-mentioned research, the present invention proposes a load recovery method after a distribution network fault taking into account the minimum duration, in order to synergistically consider the minimum duration of the microgrid and the mobile emergency power supply vehicle to improve the post-disaster recovery efficiency and ensure that the distribution network can operate stably after the disaster, thereby improving the safety and reliability of the power grid.

[0004] In order to achieve the above object, the technical solution adopted by the present invention is:

[0005] The method for restoring load after a distribution network fault considering the minimum duration of the present invention is characterized in that it is performed according to the following steps:

[0006] Step 1: With the goal of maximizing the weighted load recovery amount and maximizing the minimum duration of the microgrid, the objective function H of the load recovery model after the distribution network fault is established using formula (1):

[0007] (1)

[0008] In formula (1): is the node number set of the distribution network; is a set of discrete recovery time step numbers; is the weight of the load at the i-th node; is the active power restored by the load at the i-th node at the t-th time step; For the A Boolean variable representing the node recovery state of the load at the node. =0, indicating the If the load at the node is not restored, =1, indicating the Load recovery at each node; is the weight of the second term in the objective function; is the minimum duration of the microgrid;

[0009] Step 2: Establish the distribution network radial constraints of the load recovery model after the distribution network failure;

[0010] Step 3: Establish the microgrid minimum duration constraint of the load recovery model after the distribution network failure;

[0011] Step 4: Establish the path and energy storage constraints of the mobile emergency power supply vehicle for the load recovery model after the distribution network failure;

[0012] Step 5: Establish the distribution network power flow balance and safe operation constraints of the load recovery model after the distribution network fault;

[0013] Step 6: Solve the load recovery model after the distribution network fault and obtain the load recovery plan after the distribution network fault considering the minimum duration.

[0014] The method for restoring load after a distribution network fault considering the minimum duration described in the present invention is also characterized in that step 2 is performed according to the following steps:

[0015] Step 2.1: Use formula (2) to establish the radial constraint of the distribution network:

[0016] (2)

[0017] In formula (2): is the line number set of the distribution network; is the node number set where the distributed power source is located; It is the serial number set of the candidate nodes where the mobile emergency power supply vehicle is located; is the line l between the i-th node and the j-th node ij The line recovery status Boolean variable, if =0, indicating line l ij Not restored, if =1, indicating line l ij recover; For distributed power supply and mobile emergency power supply vehicles A Boolean variable indicating whether a node is a root node. =0, indicating that the distributed power supply and mobile emergency power supply vehicle are located in the A node is not a root node. =1, indicating that the distributed power supply and mobile emergency power supply vehicle are located in the The node is the root node;

[0018] Step 2.2: Use equations (3) to (6) to establish the distribution network connectivity constraints:

[0019] (3)

[0020] (4)

[0021] (5)

[0022] (6)

[0023] In formula (3) to formula (6): For the The line between the node and the jth node Virtual trends; is the jth node and the The lines between nodes Virtual trends; For the The line between the node and the jth node Virtual trends; is the jth node and the The lines between nodes Virtual trends; For line Virtual trends; is the parameter; For the Virtual load demand at each node; For the The virtual load demand at each node.

[0024] Furthermore, in step 3, equations (7) to (11) are used to establish the minimum duration constraint of the microgrid:

[0025] (7)

[0026] (8)

[0027] (9)

[0028] (10)

[0029] (11)

[0030] In formula (7) to formula (11): is a Boolean variable indicating whether all microgrids meet the power flow balance constraint at the tth time step. = 0, indicating that all microgrids meet the power flow balance constraint at the tth time step. =1, indicating that there is a microgrid that does not satisfy the power flow balance constraint at the tth time step; For all microgrids in A Boolean variable indicating whether a time step satisfies the power flow balance constraint. =0, indicating that all microgrids in Each time step satisfies the power flow balance constraint. =1, indicating that there is a microgrid in The time step does not satisfy the power flow balance constraint; is the auxiliary variable of active power flow balance of the ith node at the tth time step; is the auxiliary variable of reactive power flow balance of the ith node at the tth time step; Is a Boolean variable indicating whether the active power deficit at the tth time step is positive. =0, indicating that the active power deficit at the tth time step is negative. =1, indicating that the active power deficit at the tth time step is positive; is a positive parameter; is a Boolean variable indicating whether all microgrids satisfy the power flow balance constraint from the initial time step to the tth time step. = 0, indicating that all microgrids satisfy the power flow balance constraint from the initial time step to the tth time step. =1, indicating that there is a microgrid that does not satisfy the power flow balance constraint from the initial time step to the tth time step; At the confidence level The number of time steps required to repair a fault location.

[0031] Further, step 4 is performed as follows:

[0032] Step 4.1: Use equations (12) to (16) to establish the path constraints of the mobile emergency power supply vehicle:

[0033] (12)

[0034] (13)

[0035] (14)

[0036] (15)

[0037] (16)

[0038] In formula (12) to formula (16): A collection of serial numbers for mobile emergency power supply vehicles; A set of serial numbers of candidate nodes where the mobile emergency power supply vehicle is located; Whether the mth mobile emergency power supply vehicle is connected to the A Boolean variable of a node, if =0, indicating that the mth mobile emergency power supply vehicle is not connected to the nodes, if =1, indicating that the mth mobile emergency power supply vehicle is connected to the nodes; Move the mth mobile emergency power supply vehicle to the The time required to move a node; is the maximum moving time of the mth mobile emergency power supply vehicle; For the A Boolean variable representing the node recovery state of the load at the node. =0, indicating the If the load at the node is not restored, =1, indicating the Load recovery at each node; is a Boolean variable indicating whether the mth mobile emergency power supply vehicle is connected to the distribution network at the tth time step. =0, indicating that the mth mobile emergency power supply vehicle is not connected to the distribution network at the tth time step. =1, indicating that the mth mobile emergency power supply vehicle is connected to the distribution network at the tth time step; is the length of one time step; is a Boolean variable indicating whether the mth mobile emergency power supply vehicle is connected to the distribution network at the t+1th time step. =0, indicating that the mth mobile emergency power supply vehicle is not connected to the distribution network at the t+1th time step. =1, indicating that the mth mobile emergency power supply vehicle is connected to the distribution network at the t+1th time step;

[0039] Step 4.2: Use equations (17) to (30) to establish the energy storage constraints of the mobile emergency power supply vehicle:

[0040] (17)

[0041] (18)

[0042] (19)

[0043] (20)

[0044] (twenty one)

[0045] (twenty two)

[0046] (twenty three)

[0047] (twenty four)

[0048] (25)

[0049] (26)

[0050] (27)

[0051] (28)

[0052] (29)

[0053] (30)

[0054] In formula (17) to formula (30): is a Boolean variable indicating whether the mth mobile emergency power supply vehicle is in a discharging state at the tth time step. =0, indicating that the mth mobile emergency power supply vehicle is not in a discharging state at the tth time step. =1, indicating that the mth mobile emergency power supply vehicle is in the discharging state at the tth time step; is a Boolean variable indicating whether the mth mobile emergency power supply vehicle is in a charging state at the tth time step. =0, indicating that the mth mobile emergency power supply vehicle is not in charging state at the tth time step. =1, indicating that the mth mobile emergency power supply vehicle is in charging state at the tth time step; is the active charging power of the mth mobile emergency power supply vehicle at the tth time step; is the active discharge power of the mth mobile emergency power supply vehicle at the tth time step; is the upper limit of the active charging power of the mth mobile emergency power supply vehicle; is the upper limit of active discharge power of the mth mobile emergency power supply vehicle; For mobile emergency power supply vehicle The active power output of a node at the tth time step; For mobile emergency power supply vehicle The reactive power output of a node at the tth time step; For the mth mobile emergency power supply vehicle Active discharge power in each time step; For the mth mobile emergency power supply vehicle Active charging power in each hour step; is the active discharge power of the mth mobile emergency power supply vehicle at the initial time step; is the active charging power of the mth mobile emergency power supply vehicle at the initial time step; is the minimum reactive power output of the mth mobile emergency power supply vehicle; is the maximum reactive power output of the mth mobile emergency power supply vehicle; is the remaining energy of the mth mobile emergency power supply vehicle at the tth time step; is the initial energy of the mth mobile emergency power supply vehicle at the first time step; is the initial energy of the mth mobile emergency power supply vehicle at the initial time step; is the charging and discharging efficiency of the mth mobile emergency power supply vehicle; is the lower limit of energy of the mth mobile emergency power supply vehicle; is the energy limit of the mth mobile emergency power supply vehicle; is the total number of time steps; For the mth mobile emergency power supply vehicle Time step to The lower limit of energy within a time step.

[0055] Further, step five is performed as follows:

[0056] Step 5.1: Use equations (31) to (36) to establish the power flow balance constraint of the distribution network:

[0057] (31)

[0058] (32)

[0059] (33)

[0060] (34)

[0061] (35)

[0062] (36)

[0063] In formula (31) to formula (36): is the active power output of the distributed generation at the i-th node at the t-th time step; is the reactive power output of the distributed generation at the i-th node at the t-th time step; is the line between the jth node and the ith node Active transmission power at time step t; For line Active transmission power at time step t; For line Reactive transmission power at time step t; For line Reactive transmission power at time step t; For line The resistance value; For line The reactance value; For the flow line The magnitude of the current at the tth time step; is the reactive power restored by the load at the i-th node at the t-th time step; is the actual active power demand of the load at the i-th node at the t-th time step; is the actual reactive power demand of the load at the ith node at the tth time step; is the active load shedding power of the load at the i-th node at the t-th time step; is the reactive load shedding power of the load at the i-th node at the t-th time step; is the minimum load shedding rate of the active power of the load at the i-th node; is the minimum reactive power load shedding rate of the load at the i-th node;

[0064] Step 5.2: Use equations (37) to (49) to establish distribution network safety operation constraints:

[0065] (37)

[0066] (38)

[0067] (39)

[0068] (40)

[0069] (41)

[0070] (42)

[0071] (43)

[0072] (44)

[0073] (45)

[0074] (46)

[0075] (47)

[0076] (48)

[0077] (49)

[0078] In formula (37) to formula (49): is a set of serial numbers of fault lines in the distribution network; is a set of serial numbers of fault nodes in the distribution network; is the square of the voltage of the jth node at the tth time step; is the square of the voltage of the i-th node at the t-th time step; For line The square of the current flowing at the tth time step; To pass the line Maximum current; To pass the line The maximum apparent power of The minimum voltage limit of each restored node in the distribution network; The maximum voltage limit of each restored node in the distribution network; For the A Boolean variable representing the node recovery state of the load at the failed node. =0, indicating the If the load at the failed node is not restored, =1, indicating the Load recovery at each failed node; For distributed power generation The active power output of a node at the tth time step; For distributed power generation The reactive power output of a node at the tth time step; For the A Boolean variable representing the node recovery state of the load at the node. =0, indicating the If the load at the node is not restored, =1, indicating the Load recovery at each node; For distributed power generation The minimum active output at each node; For distributed power generation The maximum active output at each node; For distributed power generation The minimum reactive power output at each node; For distributed power generation The maximum reactive power output at a node.

[0079] Further, step six is ​​performed as follows:

[0080] Step 6.1, initialization parameters;

[0081] Step 6.1.1, obtain the initial data of the distribution network, including: the resistance and reactance data of each line of the distribution network, the actual active power and reactive power demand of each node at each time step, the apparent power of the maximum transmission energy of each line, the maximum transmission current of each line, the minimum load shedding rate of the active and reactive power of the load of each node, the fault node and line data, the upper and lower limits of the voltage of each node, and the upper and lower limits of the output of the distributed power source;

[0082] Step 6.1.2, obtain the initial data of the minimum duration of the microgrid, including: The number of time steps required to repair a fault location;

[0083] Step 6.1.3, obtain the initial data of the path and energy storage of the mobile emergency power supply vehicle, including: the candidate positions of the mobile emergency power supply vehicle, the transfer time of the mobile emergency power supply vehicle between the candidate positions, the maximum driving time of each mobile emergency power supply vehicle; the maximum active power of charging and discharging of each mobile emergency power supply vehicle; the initial energy of each mobile emergency power supply vehicle; the maximum and minimum energy of each mobile emergency power supply vehicle; the maximum reactive power of each mobile emergency power supply vehicle;

[0084] Step 6.2: Use the solver to solve the load recovery model after the distribution network fault, and obtain the load recovery plan after the distribution network fault considering the minimum duration, including: the minimum duration of the microgrid, the path scheduling of the mobile emergency power supply vehicle, the output scheduling value of the mobile emergency power supply vehicle, the recovery order of the line and the node, the output scheduling value of the distributed power source, and the load shedding value of each node.

[0085] An electronic device of the present invention includes a memory and a processor, wherein the memory is used to store a program that supports the processor to execute the load recovery method after a distribution network failure, and the processor is configured to execute the program stored in the memory.

[0086] The present invention provides a computer-readable storage medium, wherein a computer program is stored on the computer-readable storage medium, and the computer program executes the steps of the method for restoring load after a distribution network failure when the computer program is executed by a processor.

[0087] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0088] 1. The present invention establishes a constraint on the minimum duration of the microgrid, which ensures the power balance of the distribution network during the recovery process and avoids the problem of voltage and frequency fluctuations. By introducing the constraint on the minimum duration of the microgrid, the present invention ensures the continuity of power supply when the microgrid is operating in an isolated island, thereby avoiding system instability caused by voltage and frequency fluctuations. The constraint on the minimum duration of the microgrid optimizes the coordinated scheduling of the microgrid and distributed power sources, so that the power transmission is balanced during the recovery process, effectively avoiding the unbalanced power flow phenomenon that may occur in traditional methods, and further ensuring the stability and reliability of the power supply.

[0089] 2. The present invention establishes path constraints and energy storage constraints for mobile emergency power supply vehicles by considering the impact of mobile emergency power supply vehicles on load recovery after distribution network failures, thereby accelerating the recovery speed of the distribution network and reducing power outage losses. By rationally planning the path and energy storage scheduling of the emergency power supply vehicle, the present invention can quickly deploy emergency power supplies and provide necessary power support when a distribution network failure occurs. Compared with traditional diesel generator sets, mobile emergency power supply vehicles can not only respond to load demands more flexibly, but also mobilize energy storage systems more efficiently, significantly improving the recovery speed, shortening the power outage time, and thus reducing power outage losses.

[0090] 3. In view of the fact that local resources of the distribution network are insufficient to restore all loads, the present invention considers load weights and gives priority to restoring important loads to ensure that critical loads are powered in a timely manner. By comprehensively considering the importance and urgency of various loads, key loads such as medical, communication and other public service loads are restored first. By setting load weights, it is ensured that in the case of resource constraints, the most important loads can be restored as soon as possible, ensuring the safety of personnel and the normal operation of society, thereby effectively reducing the impact of disasters on people's livelihood. BRIEF DESCRIPTION OF THE DRAWINGS

[0091] Figure 1 It is a framework diagram of the method of the present invention. DETAILED DESCRIPTION

[0092] In this embodiment, a method for load recovery after a distribution network fault that takes into account the minimum duration is used in the load recovery stage of the distribution network, and a commercial solver can be called for efficient solution, including: 1. Establishing the objective function of the load recovery model after a distribution network fault with the goal of maximizing the weighted load recovery amount and maximizing the minimum duration of the microgrid; 2. Considering the radiality of the distribution network operation, establishing the radial constraint of the distribution network; 3. Considering the minimum duration of the microgrid, establishing the minimum duration constraint of the microgrid; 4. Establishing a mobile emergency power supply vehicle constraint; 5. Considering the safety of the distribution network operation, establishing the power flow balance and safe operation constraints of the distribution network; 6. Calling the solver to solve the established model to obtain the load recovery plan after the distribution network fault, including: the minimum duration of the microgrid, the path scheduling of the mobile emergency power supply vehicle, the output scheduling value of the mobile emergency power supply vehicle, the recovery order of the lines and nodes, the output scheduling value of the distributed power source, and the load shedding value of each node. Specifically, if Figure 1 As shown, the method is performed in the following steps:

[0093] Step 1: With the goal of maximizing the weighted load recovery amount and maximizing the minimum duration of the microgrid, the objective function H of the load recovery model after the distribution network fault is established using formula (1):

[0094] (1)

[0095] Formula (1) is the objective function of the load recovery model after distribution network fault, where the first term is the maximum weighted load recovery amount, and the second term is to maximize the minimum duration of the microgrid; In formula (1): is the node number set of the distribution network; is a set of discrete recovery time step numbers; is the weight of the load at the i-th node; is the active power restored by the load at the i-th node at the t-th time step; For the A Boolean variable representing the node recovery state of the load at the node. =0, indicating the If the load at the node is not restored, =1, indicating the Load recovery at each node; is the weight of the second term in the objective function; is the minimum duration of the microgrid.

[0096] Step 2: Establish the radial constraints of the distribution network for the load recovery model after distribution network failure:

[0097] Step 2.1: Use formula (2) to establish the radial constraint of the distribution network:

[0098] (2)

[0099] Formula (2) is the radial condition of the distribution network, which means that the number of restored lines is equal to the number of restored nodes minus the number of root nodes; in formula (2): is the line number set of the distribution network; is the node number set where the distributed power source is located; It is the serial number set of the candidate nodes where the mobile emergency power supply vehicle is located; is the line l between the i-th node and the j-th node ij The line recovery status Boolean variable, if =0, indicating line l ij Not restored, if =1, indicating line l ij recover; For distributed power supply and mobile emergency power supply vehicles A Boolean variable indicating whether a node is a root node. =0, indicating that the distributed power supply and mobile emergency power supply vehicle are located in the A node is not a root node. =1, indicating that the distributed power supply and mobile emergency power supply vehicle are located in the The first node is the root node.

[0100] Step 2.2: Use equations (3) to (6) to establish the distribution network connectivity constraints:

[0101] (3)

[0102] (4)

[0103] (5)

[0104] (6)

[0105] Formula (3) is the virtual power flow balance constraint for non-power nodes. Each restored load requires a certain virtual load. Formula (4)-Formula (5) are virtual power flow balance constraints applicable to candidate nodes of distributed power sources and mobile emergency power supply vehicles. If the power node is the root node, no constraint is imposed. Formula (6) indicates that only restored lines can transmit virtual power flows. In Formula (3)-Formula (6): For the The line between the node and the jth node Virtual trends; is the jth node and the The lines between nodes Virtual trends; For the The line between the node and the jth node Virtual trends; is the jth node and the The lines between nodes Virtual trends; For line Virtual trends; is an infinite parameter; For the Virtual load demand at each node; For the The virtual load demand at each node.

[0106] Step 3: Establish the microgrid minimum duration constraint of the load recovery model after the distribution network failure:

[0107] Step 3.1: Use equations (7) to (11) to establish the minimum duration constraint of the microgrid:

[0108] (7)

[0109] (8)

[0110] (9)

[0111] (10)

[0112] (11)

[0113] Formula (7)-Formula (8) is used to calculate the variable , when the power imbalance of the distribution network occurs at a certain time step =0; Formula (9) calculates the duration of the microgrid; Formula (10) calculates the variable , which is used to determine whether each microgrid is in a power balance state before the tth time step; Formula (11) ensures that the operation time of each microgrid can last until the fault repair is completed; In Formula (7)-Formula (11): is a Boolean variable indicating whether all microgrids meet the power flow balance constraint at the tth time step. = 0, indicating that all microgrids meet the power flow balance constraint at the tth time step. =1, indicating that there is a microgrid that does not satisfy the power flow balance constraint at the tth time step; For all microgrids in A Boolean variable indicating whether a time step satisfies the power flow balance constraint. =0, indicating that all microgrids in Each time step satisfies the power flow balance constraint. =1, indicating that there is a microgrid in The time step does not satisfy the power flow balance constraint; is the auxiliary variable of active power flow balance of the ith node at the tth time step; is the auxiliary variable of reactive power flow balance of the ith node at the tth time step; Is a Boolean variable indicating whether the active power deficit at the tth time step is positive. =0, indicating that the active power deficit at the tth time step is negative. =1, indicating that the active power deficit at the tth time step is positive; is a positive parameter approaching 0; is a Boolean variable indicating whether all microgrids satisfy the power flow balance constraint from the initial time step to the tth time step. = 0, indicating that all microgrids satisfy the power flow balance constraint from the initial time step to the tth time step. =1, indicating that there is a microgrid that does not satisfy the power flow balance constraint from the initial time step to the tth time step; At the confidence level The number of time steps required to repair a fault location.

[0114] Step 4: Establish the path and energy storage constraints of the mobile emergency power supply vehicle for the load recovery model after the distribution network failure:

[0115] Step 4.1: Use equations (12) to (16) to establish the path constraints of the mobile emergency power supply vehicle:

[0116] (12)

[0117] (13)

[0118] (14)

[0119] (15)

[0120] (16)

[0121] Formula (12) ensures that the travel time of the mth mobile emergency power supply vehicle from its current position to the ith node should not exceed its maximum travel time; Formula (13) ensures that each mobile emergency power supply vehicle can access at most one candidate node; Formula (14) ensures that the mobile emergency power supply vehicle can only access the ith node after it has been restored; Formula (15) ensures that the mobile emergency power supply vehicle can only access the distribution network after moving to the candidate node; Formula (16) ensures that the mobile emergency power supply vehicle cannot leave after accessing a candidate node; In Formulas (12)-(16): A collection of serial numbers for mobile emergency power supply vehicles; A set of serial numbers of candidate nodes where the mobile emergency power supply vehicle is located; Whether the mth mobile emergency power supply vehicle is connected to the A Boolean variable of a node, if =0, indicating that the mth mobile emergency power supply vehicle is not connected to the nodes, if =1, indicating that the mth mobile emergency power supply vehicle is connected to the nodes; Move the mth mobile emergency power supply vehicle to the The time required to move a node; is the maximum moving time of the mth mobile emergency power supply vehicle; For the A Boolean variable representing the node recovery state of the load at the node. =0, indicating the If the load at the node is not restored, =1, indicating the Load recovery at each node; is a Boolean variable indicating whether the mth mobile emergency power supply vehicle is connected to the distribution network at the tth time step. =0, indicating that the mth mobile emergency power supply vehicle is not connected to the distribution network at the tth time step. =1, indicating that the mth mobile emergency power supply vehicle is connected to the distribution network at the tth time step; is the length of one time step; is a Boolean variable indicating whether the mth mobile emergency power supply vehicle is connected to the distribution network at the t+1th time step. =0, indicating that the mth mobile emergency power supply vehicle is not connected to the distribution network at the t+1th time step. =1, indicating that the mth mobile emergency power supply vehicle is connected to the distribution network at the t+1th time step.

[0122] Step 4.2: Use equations (17) to (30) to establish the energy storage constraints of the mobile emergency power supply vehicle:

[0123] (17)

[0124] (18)

[0125] (19)

[0126] (20)

[0127] (twenty one)

[0128] (twenty two)

[0129] (twenty three)

[0130] (twenty four)

[0131] (25)

[0132] (26)

[0133] (27)

[0134] (28)

[0135] (29)

[0136] (30)

[0137] Formula (17) ensures that the mobile emergency power supply vehicle can be in the discharging state only after it is connected to the distribution network; Formula (18) ensures that the mobile emergency power supply vehicle can be in the charging state only after it is connected to the distribution network; Formula (19) ensures that the mobile emergency power supply vehicle can only be in one of the charging or discharging states; Formula (20)-Formula (21) limit the maximum charging and discharging active power of the mobile emergency power supply vehicle; Formula (22) is the climbing limit of the mobile emergency power supply vehicle; Formula (23)-Formula (24) limits the mobile emergency power supply vehicle in the first The upper and lower limits of active power charging and discharging of each node; Formula (25)-Formula (26) limits the mobile emergency power supply vehicle in the first The upper and lower limits of reactive power charging and discharging of nodes; Formula (27) gives the residual energy of the mobile emergency power supply vehicle at the first time step; Formula (28) calculates the residual energy of the mobile emergency power supply vehicle at each time step; Formula (29) limits the upper and lower limits of the residual energy of the mobile emergency power supply vehicle; Formula (30) limits the lower limit of the energy of the mobile emergency power supply vehicle within the time step from the completion of the fault repair to the set total time step; In formulas (17) to (30): is a Boolean variable indicating whether the mth mobile emergency power supply vehicle is in a discharging state at the tth time step. =0, indicating that the mth mobile emergency power supply vehicle is not in a discharging state at the tth time step. =1, indicating that the mth mobile emergency power supply vehicle is in the discharging state at the tth time step; is a Boolean variable indicating whether the mth mobile emergency power supply vehicle is in a charging state at the tth time step. =0, indicating that the mth mobile emergency power supply vehicle is not in charging state at the tth time step. =1, indicating that the mth mobile emergency power supply vehicle is in charging state at the tth time step; is the active charging power of the mth mobile emergency power supply vehicle at the tth time step; is the active discharge power of the mth mobile emergency power supply vehicle at the tth time step; is the upper limit of the active charging power of the mth mobile emergency power supply vehicle; is the upper limit of active discharge power of the mth mobile emergency power supply vehicle; For mobile emergency power supply vehicle The active power output of a node at the tth time step; For mobile emergency power supply vehicle The reactive power output of a node at the tth time step; For the mth mobile emergency power supply vehicle Active discharge power in each time step; For the mth mobile emergency power supply vehicle Active charging power in each hour step; is the active discharge power of the mth mobile emergency power supply vehicle at the initial time step; is the active charging power of the mth mobile emergency power supply vehicle at the initial time step; is the minimum reactive power output of the mth mobile emergency power supply vehicle; is the maximum reactive power output of the mth mobile emergency power supply vehicle; is the remaining energy of the mth mobile emergency power supply vehicle at the tth time step; is the initial energy of the mth mobile emergency power supply vehicle at the first time step; is the initial energy of the mth mobile emergency power supply vehicle at the initial time step; is the charging and discharging efficiency of the mth mobile emergency power supply vehicle; is the lower limit of energy of the mth mobile emergency power supply vehicle; is the energy limit of the mth mobile emergency power supply vehicle; is the total number of time steps; For the mth mobile emergency power supply vehicle Time step to The lower limit of energy within a time step.

[0138] Step 5: Establish the distribution network power flow balance and safe operation constraints of the load recovery model after the distribution network failure:

[0139] Step 5.1: Use equations (31) to (36) to establish the power flow balance constraint of the distribution network:

[0140] (31)

[0141] (32)

[0142] (33)

[0143] (34)

[0144] (35)

[0145] (36)

[0146] Formula (31)-Formula (32) is the active and reactive power flow balance constraint of the distribution network; Formula (33) is the active power load shedding calculation formula of the load; Formula (34) is the reactive power load shedding calculation formula of the load; Formula (35) is the upper and lower limits of the active power load shedding of the load; Formula (36) is the upper and lower limits of the reactive power load shedding of the load; In Formula (31)-Formula (36): is the active power output of the distributed generation at the i-th node at the t-th time step; is the reactive power output of the distributed generation at the i-th node at the t-th time step; is the line between the jth node and the ith node Active transmission power at time step t; For line Active transmission power at time step t; For line Reactive transmission power at time step t; For line Reactive transmission power at time step t; For line The resistance value; For line The reactance value; For the flow line The magnitude of the current at the tth time step; is the reactive power restored by the load at the i-th node at the t-th time step; is the actual active power demand of the load at the i-th node at the t-th time step; is the actual reactive power demand of the load at the ith node at the tth time step; is the active load shedding power of the load at the i-th node at the t-th time step; is the reactive load shedding power of the load at the i-th node at the t-th time step; is the minimum load shedding rate of the active power of the load at the i-th node; is the minimum reactive power load shedding rate of the load at the i-th node.

[0147] Step 5.2: Use equations (37) to (49) to establish distribution network safety operation constraints:

[0148] (37)

[0149] (38)

[0150] (39)

[0151] (40)

[0152] (41)

[0153] (42)

[0154] (43)

[0155] (44)

[0156] (45)

[0157] (46)

[0158] (47)

[0159] (48)

[0160] (49)

[0161] Formula (37)-(38) is the voltage drop calculation formula; Formula (39) is the relaxed second-order cone formula of the relationship between the voltage and current of the line and the transmission power; Formula (40)-(41) gives the limits of the active power and reactive power of the line transmission; Formula (42)-(43) gives the limits of the apparent power of the line transmission; Formula (44) ensures that the line transmission current does not exceed the limit; Formula (45) ensures that the distribution network voltage does not exceed the limit; Formula (46) sets the fault node number; Formula (47) sets the fault line number; Formula (48) is the active output limit of the distributed power source; Formula (49) is the reactive output limit of the distributed power source; In Formula (37)-(49): is a set of serial numbers of fault lines in the distribution network; is a set of serial numbers of fault nodes in the distribution network; is the square of the voltage of the jth node at the tth time step; is the square of the voltage of the i-th node at the t-th time step; For line The square of the current flowing at the tth time step; To be able to pass the line Maximum current; To be able to pass the line The maximum apparent power of The minimum voltage limit of each restored node in the distribution network; The maximum voltage limit of each restored node in the distribution network; For the A Boolean variable representing the node recovery state of the load at the failed node. =0, indicating the If the load at the failed node is not restored, =1, indicating the Load recovery at each failed node; For distributed power generation The active power output of a node at the tth time step; For distributed power generation The reactive power output of a node at the tth time step; For the A Boolean variable representing the node recovery state of the load at the node. =0, indicating the If the load at the node is not restored, =1, indicating the Load recovery at each node; For distributed power generation The minimum active output at each node; For distributed power generation The maximum active output at each node; For distributed power generation The minimum reactive power output at each node; For distributed power generation The maximum reactive power output at a node.

[0162] Step 6: Solve the load recovery model after the distribution network fault and obtain the load recovery plan after the distribution network fault considering the minimum duration:

[0163] Step 6.1, initialization parameters;

[0164] Step 6.1.1, obtain the initial data of the distribution network, including: the resistance and reactance data of each line of the distribution network, the actual active power and reactive power demand of each node at each time step, the apparent power of the maximum transmission energy of each line, the maximum transmission current of each line, the minimum load shedding rate of the active and reactive power of the load of each node, the fault node and line data, the upper and lower limits of the voltage of each node, and the upper and lower limits of the output of the distributed power source;

[0165] Step 6.1.2, obtain the initial data of the minimum duration of the microgrid, including: The number of time steps required to repair a fault location;

[0166] Step 6.1.3, obtain the initial data of the path and energy storage of the mobile emergency power supply vehicle, including: the candidate positions of the mobile emergency power supply vehicle, the transfer time of the mobile emergency power supply vehicle between the candidate positions, the maximum driving time of each mobile emergency power supply vehicle; the maximum active power of charging and discharging of each mobile emergency power supply vehicle; the initial energy of each mobile emergency power supply vehicle; the maximum and minimum energy of each mobile emergency power supply vehicle; the maximum reactive power of each mobile emergency power supply vehicle;

[0167] Step 6.2: Use the solver to solve the load recovery model after the distribution network fault, and obtain the load recovery plan after the distribution network fault considering the minimum duration, including: the minimum duration of the microgrid, the path scheduling of the mobile emergency power supply vehicle, the output scheduling value of the mobile emergency power supply vehicle, the recovery order of the line and the node, the output scheduling value of the distributed power source, and the load shedding value of each node.

[0168] In this embodiment, an electronic device includes a memory and a processor, wherein the memory is used to store a program that supports the processor to execute the above method, and the processor is configured to execute the program stored in the memory.

[0169] In this embodiment, a computer-readable storage medium stores a computer program on the computer-readable storage medium, and the computer program executes the steps of the above method when executed by a processor.

Claims

1. A method for restoring load after a distribution network fault considering a minimum duration, characterized in that: The steps are as follows: Step 1: With the goal of maximizing the weighted load recovery amount and maximizing the minimum duration of the microgrid, the objective function H of the load recovery model after the distribution network fault is established using formula (1): (1) In formula (1): is the node number set of the distribution network; is a set of discrete recovery time step numbers; is the weight of the load at the i-th node; is the active power restored by the load at the i-th node at the t-th time step; For the A Boolean variable representing the node recovery state of the load at the node. =0, indicating the If the load at the node is not restored, =1, indicating the Load recovery at each node; is the weight of the second term in the objective function; is the minimum duration of the microgrid; Step 2: Establish the distribution network radial constraints of the load recovery model after the distribution network failure; Step 3: Establish the microgrid minimum duration constraint of the load recovery model after the distribution network failure; Step 4: Establish the path and energy storage constraints of the mobile emergency power supply vehicle for the load recovery model after the distribution network failure; Step 5: Establish the distribution network power flow balance and safe operation constraints of the load recovery model after the distribution network fault; Step 6: Solve the load recovery model after the distribution network fault and obtain the load recovery plan after the distribution network fault considering the minimum duration.

2. A method for restoring load after a distribution network fault considering a minimum duration according to claim 1, characterized in that: Step 2 is performed as follows: Step 2.1: Use formula (2) to establish the radial constraint of the distribution network: (2) In formula (2): is the line number set of the distribution network; is the node number set where the distributed power source is located; A set of serial numbers of candidate nodes where the mobile emergency power supply vehicle is located; is the line l between the i-th node and the j-th node ij The line recovery status Boolean variable, if =0, indicating line l ij Not restored, if =1, indicating line l ij recover; The first one is where the distributed power supply and mobile emergency power supply vehicle are located. A Boolean variable indicating whether a node is a root node. =0, indicating that the distributed power supply and mobile emergency power supply vehicle are located in the A node is not a root node. =1, indicating that the distributed power supply and mobile emergency power supply vehicle are located in the The node is the root node; Step 2.2: Use equations (3) to (6) to establish the distribution network connectivity constraints: (3) (4) (5) (6) In formula (3) to formula (6): For the The line between the node and the jth node Virtual trends; is the jth node and the The lines between nodes Virtual trends; For the The line between the node and the jth node Virtual trends; is the jth node and the The lines between nodes Virtual trends; For line Virtual trends; is the parameter; For the Virtual load demand at each node; For the The virtual load demand at each node.

3. A method for restoring load after a distribution network fault considering a minimum duration according to claim 2, characterized in that: In step 3, equations (7) to (11) are used to establish the minimum duration constraint of the microgrid: (7) (8) (9) (10) (11) In formula (7) to formula (11): is a Boolean variable indicating whether all microgrids meet the power flow balance constraint at the tth time step. = 0, indicating that all microgrids meet the power flow balance constraint at the tth time step. =1, indicating that there is a microgrid that does not satisfy the power flow balance constraint at the tth time step; For all microgrids in A Boolean variable indicating whether a time step satisfies the power flow balance constraint. =0, indicating that all microgrids in Each time step satisfies the power flow balance constraint. =1, indicating that there is a microgrid in The time step does not satisfy the power flow balance constraint; is the auxiliary variable of active power flow balance of the ith node at the tth time step; is the auxiliary variable of reactive power flow balance of the ith node at the tth time step; Is a Boolean variable indicating whether the active power deficit at the tth time step is positive. =0, indicating that the active power deficit at the tth time step is negative. =1, indicating that the active power deficit at the tth time step is positive; is a positive parameter; is a Boolean variable indicating whether all microgrids satisfy the power flow balance constraint from the initial time step to the tth time step. = 0, indicating that all microgrids satisfy the power flow balance constraint from the initial time step to the tth time step. =1, indicating that there is a microgrid that does not satisfy the power flow balance constraint from the initial time step to the tth time step; At the confidence level The number of time steps required to repair a fault location.

4. A method for restoring load after a distribution network fault considering minimum duration according to claim 3, characterized in that: Step 4 is carried out as follows: Step 4.1: Use equations (12) to (16) to establish the path constraints of the mobile emergency power supply vehicle: (12) (13) (14) (15) (16) In formula (12) to formula (16): A collection of serial numbers for mobile emergency power supply vehicles; A set of serial numbers of candidate nodes where the mobile emergency power supply vehicle is located; Is the mth mobile emergency power supply vehicle connected to the A Boolean variable of a node, if =0, indicating that the mth mobile emergency power supply vehicle is not connected to the nodes, if =1, indicating that the mth mobile emergency power supply vehicle is connected to the nodes; Move the mth mobile emergency power supply vehicle to the The time required to move a node; is the maximum moving time of the mth mobile emergency power supply vehicle; For the A Boolean variable representing the node recovery state of the load at the node. =0, indicating the If the load at the node is not restored, =1, indicating the Load recovery at each node; is a Boolean variable indicating whether the mth mobile emergency power supply vehicle is connected to the distribution network at the tth time step. =0, indicating that the mth mobile emergency power supply vehicle is not connected to the distribution network at the tth time step. =1, indicating that the mth mobile emergency power supply vehicle is connected to the distribution network at the tth time step; is the length of one time step; is a Boolean variable indicating whether the mth mobile emergency power supply vehicle is connected to the distribution network at the t+1th time step. =0, indicating that the mth mobile emergency power supply vehicle is not connected to the distribution network at the t+1th time step. =1, indicating that the mth mobile emergency power supply vehicle is connected to the distribution network at the t+1th time step; Step 4.2: Use equations (17) to (30) to establish the energy storage constraints of the mobile emergency power supply vehicle: (17) (18) (19) (20) (21) (22) (23) (24) (25) (26) (27) (28) (29) (30) In formula (17) to formula (30): is a Boolean variable indicating whether the mth mobile emergency power supply vehicle is in a discharging state at the tth time step. =0, indicating that the mth mobile emergency power supply vehicle is not in a discharging state at the tth time step. =1, indicating that the mth mobile emergency power supply vehicle is in the discharging state at the tth time step; is a Boolean variable indicating whether the mth mobile emergency power supply vehicle is in a charging state at the tth time step. =0, indicating that the mth mobile emergency power supply vehicle is not in charging state at the tth time step. =1, indicating that the mth mobile emergency power supply vehicle is in charging state at the tth time step; is the active charging power of the mth mobile emergency power supply vehicle at the tth time step; is the active discharge power of the mth mobile emergency power supply vehicle at the tth time step; is the upper limit of the active charging power of the mth mobile emergency power supply vehicle; is the upper limit of active discharge power of the mth mobile emergency power supply vehicle; For mobile emergency power supply vehicle The active power output of a node at the tth time step; For mobile emergency power supply vehicle The reactive power output of a node at the tth time step; For the mth mobile emergency power supply vehicle Active discharge power in each time step; For the mth mobile emergency power supply vehicle Active charging power in each hour step; is the active discharge power of the mth mobile emergency power supply vehicle at the initial time step; is the active charging power of the mth mobile emergency power supply vehicle at the initial time step; is the minimum reactive power output of the mth mobile emergency power supply vehicle; is the maximum reactive power output of the mth mobile emergency power supply vehicle; is the remaining energy of the mth mobile emergency power supply vehicle at the tth time step; is the initial energy of the mth mobile emergency power supply vehicle at the first time step; is the initial energy of the mth mobile emergency power supply vehicle at the initial time step; is the charging and discharging efficiency of the mth mobile emergency power supply vehicle; is the lower limit of energy of the mth mobile emergency power supply vehicle; is the energy limit of the mth mobile emergency power supply vehicle; is the total number of time steps; For the mth mobile emergency power supply vehicle Time step to The lower limit of energy within a time step.

5. A method for restoring load after a distribution network fault considering a minimum duration according to claim 4, characterized in that: Step five is carried out as follows: Step 5.1: Use equations (31) to (36) to establish the power flow balance constraint of the distribution network: (31) (32) (33) (34) (35) (36) In formula (31) to formula (36): is the active power output of the distributed generation at the i-th node at the t-th time step; is the reactive power output of the distributed generation at the i-th node at the t-th time step; is the line between the jth node and the ith node Active transmission power at time step t; For line Active transmission power at time step t; For line Reactive transmission power at time step t; For line Reactive transmission power at time step t; For line The resistance value; For line The reactance value; For the flow line The magnitude of the current at the tth time step; is the reactive power restored by the load at the i-th node at the t-th time step; is the actual active power demand of the load at the i-th node at the t-th time step; is the actual reactive power demand of the load at the ith node at the tth time step; is the active load shedding power of the load at the i-th node at the t-th time step; is the reactive load shedding power of the load at the i-th node at the t-th time step; is the minimum load shedding rate of the active power of the load at the i-th node; is the minimum reactive power load shedding rate of the load at the i-th node; Step 5.2: Use equations (37) to (49) to establish distribution network safety operation constraints: (37) (38) (39) (40) (41) (42) (43) (44) (45) (46) (47) (48) (49) In formula (37) to formula (49): is a set of serial numbers of fault lines in the distribution network; is a set of serial numbers of fault nodes in the distribution network; is the square of the voltage of the jth node at the tth time step; is the square of the voltage of the i-th node at the t-th time step; For line The square of the current flowing at the tth time step; To pass the line Maximum current; To pass the line The maximum apparent power of The minimum voltage limit of each restored node in the distribution network; The maximum voltage limit of each restored node in the distribution network; For the A Boolean variable representing the node recovery state of the load at the failed node. =0, indicating the If the load at the failed node is not restored, =1, indicating the Load recovery at each failed node; For distributed power generation The active power output of a node at the tth time step; For distributed power generation The reactive power output of a node at the tth time step; For the A Boolean variable representing the node recovery state of the load at the node. =0, indicating the If the load at the node is not restored, =1, indicating the Load recovery at each node; For distributed power generation The minimum active output at each node; For distributed power generation The maximum active output at each node; For distributed power generation The minimum reactive power output at each node; For distributed power generation The maximum reactive power output at a node.

6. A method for restoring load after a distribution network fault considering a minimum duration according to claim 5, characterized in that: Step six is ​​carried out as follows: Step 6.1, initialization parameters; Step 6.1.1, obtain the initial data of the distribution network, including: the resistance and reactance data of each line of the distribution network, the actual active power and reactive power demand of each node at each time step, the apparent power of the maximum transmission energy of each line, the maximum transmission current of each line, the minimum load shedding rate of the active and reactive power of the load of each node, the fault node and line data, the upper and lower limits of the voltage of each node, and the upper and lower limits of the output of the distributed power source; Step 6.1.2, obtain the initial data of the minimum duration of the microgrid, including: The number of time steps required to repair a fault location; Step 6.1.3, obtain the initial data of the path and energy storage of the mobile emergency power supply vehicle, including: the candidate positions of the mobile emergency power supply vehicle, the transfer time of the mobile emergency power supply vehicle between the candidate positions, the maximum driving time of each mobile emergency power supply vehicle; the maximum active power of charging and discharging of each mobile emergency power supply vehicle; the initial energy of each mobile emergency power supply vehicle; the maximum and minimum energy of each mobile emergency power supply vehicle; the maximum reactive power of each mobile emergency power supply vehicle; Step 6.2: Use the solver to solve the load recovery model after the distribution network fault, and obtain the load recovery plan after the distribution network fault considering the minimum duration, including: the minimum duration of the microgrid, the path scheduling of the mobile emergency power supply vehicle, the output scheduling value of the mobile emergency power supply vehicle, the recovery order of the line and the node, the output scheduling value of the distributed power source, and the load shedding value of each node.

7. An electronic device, comprising a memory and a processor, characterized in that: The memory is used to store a program that supports the processor to execute the load recovery method after a distribution network failure as described in any one of claims 1-6, and the processor is configured to execute the program stored in the memory.

8. A computer-readable storage medium having a computer program stored thereon, characterized in that: When the computer program is executed by a processor, the steps of the method for restoring load after a distribution network failure described in any one of claims 1 to 6 are executed.

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