Active power distribution network recovery method considering electric vehicle and island division

Abstract

The invention discloses an active power distribution network recovery method considering electric vehicles and island division. The method comprises the following steps: 1, establishing a charging and discharging model of the electric vehicles and a charging and swapping station; 2, establishing a dynamic island division model based on a loop radiation elimination method; 3, taking minimization of power failure load, switch action times and power distribution island scale as a target function, considering power distribution network flow constraint, a power distribution line fault rate model and load reserve constraint, and establishing an active power distribution network recovery model considering electric vehicle load and dynamic island division; and 4, solving the active power distribution network recovery model considering the electric vehicle and island division, and obtaining an electric vehicle load charging and discharging scheduling scheme and a dynamic island division scheme so as to obtain an active power distribution network recovery scheme. The potential of the electric vehicle load participating in power distribution network recovery can be effectively dispatched, and by dynamically adjusting the operation state of the power distribution island, the elasticity of the power distribution network is effectively improved, and the loss of the power distribution network in the power failure recovery stage is reduced.

Description

Technical Field

[0001] This invention belongs to the field of power system fault recovery, and specifically relates to an active distribution network recovery strategy that takes into account electric vehicles and islanding. Background Technology

[0002] With the increasing frequency of power system failures caused by extreme natural disasters and man-made information attacks, the construction of an active distribution network capable of comprehensively sensing the power grid situation, coordinating internal and external resources, proactively predicting disturbances, and rapidly restoring critical loads is becoming increasingly urgent. Active distribution network restoration primarily involves ensuring power supply to some critical loads through distributed generation after disconnection from the upstream power system until the fault is resolved. With the development of the new energy vehicle industry, electric vehicles, as a new type of power load, are accounting for an increasingly larger proportion in the distribution network. Their spatiotemporal distribution characteristics, unlike traditional power loads, and their ability to support active distribution network restoration as distributed generation are of great significance for analyzing distribution network restoration. Islanding is the process of creating independent power supply areas in the distribution network after disconnection from the upstream power system by adjusting switches and scheduling distributed generation. The formation of distribution islands can prioritize the restoration of critical loads and reduce economic losses during fault recovery. Traditional power systems are insufficiently prepared for unpredictable extreme disasters and have significant vulnerabilities. Traditional distribution network restoration strategies only perform islanding based on the system situation after a fault, failing to fully explore the potential of electric vehicle loads in restoration and thus failing to meet the requirements of highly resilient active distribution network restoration. Summary of the Invention

[0003] This invention addresses the shortcomings of existing technologies by proposing an active distribution network recovery strategy that considers electric vehicles and islanding. The strategy aims to effectively schedule electric vehicle loads to participate in power supply and extend the existence time of distribution islands after the distribution network is disconnected from the upstream power system. Simultaneously, it dynamically adjusts the framework of the distribution islands based on the real-time status of the distribution network, ensuring power supply to critical loads while stabilizing voltage and power quality, and facilitating fault diagnosis and maintenance.

[0004] To achieve the above-mentioned objectives, the present invention adopts the following technical solution: The active distribution network restoration method of the present invention, which takes into account electric vehicles and islanding, is characterized by the following steps: Step 1: Based on the spatiotemporal travel characteristics of electric vehicles, establish a charging and discharging model for electric vehicles and charging / swapping stations; Step 2: Establish a dynamic islanding operation model based on loop radiation elimination, including: islanding model, active distribution network power flow model, and operational constraints of the active distribution network; Step 3: Based on the charging and discharging model and the dynamic islanding model, establish an active distribution network recovery model that considers electric vehicle load and islanding operation; Step 4: Use the commercial solver CPLEX to solve the active distribution network recovery model to obtain the distribution network recovery scheme, including: the recovery sequence of each node and distribution line of the distribution network, the charging and discharging strategy of electric vehicle loads, and the load recovery strategy of distribution network nodes.

[0005] The active distribution network restoration method described in this invention is characterized in that step one is performed as follows: Step 1.1: Construct a spatiotemporal demand model for electric vehicle charging and swapping based on the origin-destination matrix using equations (1)-(5): (1) (2) (3) (4) (5) In equations (1)-(5): wheel dis This refers to the average driving distance of an electric vehicle under a fixed operating cycle. t s and t e This refers to the departure and arrival times of electric vehicles within a fixed operating cycle. , and Let be the probability density functions of the electric vehicle's mileage, departure time, and arrival time, respectively, under a fixed operating cycle. μ D , μ S and μ E These are the standard values ​​for the probability distributions of electric vehicle travel mileage, travel start time, and travel end time, respectively. σ D , σ S and σ E These are the standard deviations of the probability distributions for electric vehicle trip mileage, trip start time, and trip end time, respectively. ξ To represent a Boolean variable for day and night, if ξ =1 indicates daytime. ξ =0 indicates nighttime; Ω W and Ω EV They are the set of traffic network nodes and the set of electric vehicles, respectively; Ω T A set of time periods under a fixed period; Trip k For electric vehicles kThe set of nodes in the transportation network; Δ l gh For traffic network nodes g To transportation network nodes h The driving distance; Δ T gh For electric vehicles from traffic network nodes g To transportation network nodes h Travel time; p gh,t,t+ΔTgh For electric vehicles from t Time's up t+ Δ T gh Time period determined by traffic network nodes g Drive to the traffic network node h The probability of; a gh,t,t+ΔTgh From t Time's up t+ Δ T gh Time period determined by traffic network nodes g Drive to the traffic network node h The number of electric vehicles; SOC k,t For electric vehicles k exist t Remaining battery power for the specified time period; SOC k,t+ΔTgh For electric vehicles k exist t+ Δ T gh Remaining battery power for the specified time period; χ k For electric vehicles k Electricity consumption per unit distance traveled; For electric vehicles k Battery capacity; Step 1.2: Construct the charging and discharging model of the electric vehicle using equations (6)-(14): (6) (7) (8) (9) (10) In equations (6)-(10): Ω BSS It is a collection of electric vehicle charging and battery swapping stations in an active distribution network; δ k,t For electric vehicles k exist tAn auxiliary Boolean variable describing the remaining battery power over a given time period; M and ε These are the two parameters used for linearization; SOC th This represents the minimum remaining battery power of an electric vehicle. For electric vehicles k exist t Is there a need for battery swapping during certain periods? =1 indicates a need for battery swapping. =0 indicates no need for battery swapping; for t Electric vehicles during the time period k At charging and swapping stations m Is it charging? for t Electric vehicles during the time period k At charging and swapping stations m Is it in a discharge state? b m,k,t for t Electric vehicles during the time period k Is it located at a battery swapping station? m ; (11) (12) (13) (14) In equations (11)-(14): for t Time-of-use charging and battery swapping stations m The number of fully charged batteries inside. for t -1 Period Charging and Swapping Station m The number of fully charged batteries inside; for t Time-of-use charging and battery swapping stations m The number of newly added fully charged batteries; for t Time-of-use charging and battery swapping stations m The number of batteries that need to be charged. for t -1 Period Charging and Swapping Station m The number of batteries that need to be charged; for t Time-of-use charging and battery swapping stations m The number of batteries in a discharged state; t C The number of time periods required to fully charge the battery; for t - tC Electric vehicles during the time period k At charging and swapping stations m Is it charging? Step 1.3: Construct the charging and discharging model of the charging and battery swapping station using equations (15)-(17): (15) (16) (17) In equations (15)-(17): for t Time-of-use charging and battery swapping stations m Discharge power to the active distribution network, when When it is negative, it means t Time-of-use charging and battery swapping stations m Obtain electrical energy from the active distribution network to charge electric vehicle loads; For charging and battery swapping stations m Maximum discharge power; P BaC and P BaD The charging and discharging power of electric vehicle batteries.

[0006] Furthermore, step two is carried out as follows: Step 2.1: Construct an islanding model for the active distribution network using equations (18)-(26): (18) (19) (20) (twenty one) (twenty two) (twenty three) (twenty four) In equations (18)-(24): Ω DG Ω is the set of nodes in an active distribution network that are equipped with distributed generation sources. B and Ω L It is the set of nodes and the set of distribution lines in an active distribution network; S A collection of distribution islands; Ω loop For the collection of loops in an active distribution network; x i,t,s For nodes in an active distribution network i exist t The recovery status during the period, if xi,t,s =1 indicates restoration; if x i,t,s =0 indicates that it has not been restored; y ij,t,s For nodes in an active distribution network i With nodes j The power distribution lines between ij exist t The recovery status during the period, if y ij,t,s =1 indicates restoration; if y ij,t,s =0 indicates that it has not been restored; s-root For deploying distributed power sources with black-start capability in distribution islands s Potential root nodes of the distribution network; x s-root,t,s For nodes in an active distribution network s-root exist t Is the time period treated as a distribution island? s The root node; | l |For the ring road l The number of power distribution lines in the system; (25) (26) In equations (25)-(26): and For nodes in an active distribution network i and power distribution lines ij exist t The actual recovery status during the time period; Step 2.2: Construct an active distribution network power flow model based on branch power flow using equations (27)-(31): (27) (28) (29) (30) (31) In equations (27)-(31): BBS( i For nodes in the active distribution network i A collection of interconnected charging and battery swapping stations; and These are nodes in an active distribution network. i Distributed power sources at the location t The active and reactive power output during each time period. and These are nodes in an active distribution network. i exist t Reactive load and active load during a given time period; κ ij,t For power distribution lines ij exist t Failure probability over a given period; and For nodes in an active distribution network i exist t The active and reactive power of electricity restored during the time period; and They are power distribution lines ij exist t Time period is determined by nodes i To the node j The active and reactive power transmitted; and They are power distribution lines ij exist t Time period is determined by nodes z To the node i The active and reactive power transmitted; for t Time-of-use power distribution lines juice The square of the current in the medium; R ij and X ij They are power distribution lines ij Resistance and reactance; V i,t and V j,t They are respectively t Nodes in a time-sensitive active distribution network i and nodes j The square of the voltage; I ij,t for t Time-of-use power distribution lines ij The square of the current in the medium; Step 2.3: Construct the operating constraints of the active distribution network using equations (32)-(31): (32) (33) (34) (35) In equations (32)-(35): and These are nodes in an active distribution network. i The maximum active and reactive power that the distributed power source at the location can output; and These are nodes in an active distribution network. i Distributed power sources at the location t The active and reactive power output during the -1 time period; and These are nodes in an active distribution network. i The ramp rate of active and reactive power output of the distributed power source at the location; (36) (37) (38) (39) In equations (36)-(39): For power distribution lines ij The maximum apparent power that it can withstand; U min and U max These represent the minimum and maximum values ​​of node voltage in an active distribution network.

[0007] Furthermore, step three is carried out as follows: Step 3.1: With the goal of minimizing power outage load, number of switching operations, and distribution island size, construct the objective function of the active distribution network recovery model using equation (40): (40) In equation (40): Ω S_close and Ω S_open These are respectively the set of sectionalizing switches and the set of tie switches in an active distribution network; ϖ loss , ϖ sw and ϖ sca These are the objective function weighting coefficients for power outage load, number of switching operations, and distribution island size, respectively. w i For nodes in an active distribution network i The load weighting coefficient; Step 3.2: Construct power distribution line fault rate constraints using equations (41)-(44): (41) (42) (43) (44) In equations (41)-(44):m ij and C ij For power distribution lines ij Mass per unit length and specific heat capacity; τ ij,t For power distribution lines ij exist t Operating temperature during the specified time period; μ and A These are the temperature coefficient of resistance and the convective heat dissipation coefficient; τ ref and τ env The actual ambient temperature and the rated ambient temperature; For power distribution lines ij exist t The conductor diameter expansion rate over a given period; and For power distribution lines ij The initial conductor radius and in t The amount of conductor diameter expansion during the time period; v wind and p rain For wind speed and probability of rainfall; and For power distribution lines ij Horizontal and vertical load parameters; For power distribution lines ij Design load; a 1 , a 2 , b 1 , b 2 and b 3 It has 5 constant coefficients; Step 3.3: Construct the standby constraints of the active distribution network using equations (45) and (46): (45) (46) In equations (45)-(46): γ This refers to the reserve rate of the active distribution network.

[0008] The present invention provides an electronic device, including a memory and a processor, characterized in that the memory is used to store a program that supports the processor in executing the active power distribution network restoration method, and the processor is configured to execute the program stored in the memory.

[0009] The present invention discloses a computer-readable storage medium storing a computer program, characterized in that the computer program, when executed by a processor, performs the steps of the active power distribution network restoration method.

[0010] Compared with the prior art, the beneficial effects of the present invention are as follows: This invention establishes an active distribution network recovery strategy that considers electric vehicles and islanding, enabling full mobilization of electric vehicle loads to participate in the dynamic islanding operation and recovery process of the distribution network. This overcomes the insufficient resilience of traditional distribution network recovery strategies in the context of frequent power system failures caused by extreme natural disasters and human-induced information attacks. During the islanding operation phase, the source-load uncertainty of electric vehicle loads is fully considered, extending the power supply time for critical loads through battery discharge while ensuring normal electric vehicle operation. When islanding the distribution network, dynamic islanding changes are considered, ensuring that the islanding scheme adapts to the spatiotemporal distribution characteristics of electric vehicle loads. The islanding range is adjusted according to the needs of the recovery process, thereby effectively improving the elasticity and resilience of the active distribution network. Detailed Implementation

[0011] This embodiment presents an active distribution network restoration method considering electric vehicles and islanding. The distribution network system includes nodes, distribution lines, distributed power sources, and electric vehicle charging / swapping stations. First, based on the spatiotemporal travel characteristics of electric vehicles, a charging / discharging model for electric vehicles and charging / swapping stations is established. Then, considering the islanding model, the active distribution network power flow model, and the operational constraints of the active distribution network, a dynamic islanding operation model based on loop radiation elimination is established. Next, with the objective function of minimizing outage load, number of switching operations, and distribution island size, and considering distribution network power flow constraints, distribution line failure rate models, and load reserve constraints, an active distribution network restoration model considering electric vehicle load and dynamic islanding is established. Finally, the commercial solver CPLEX is used to solve the active distribution network restoration model considering electric vehicle and islanding operation, obtaining the restoration timing of each node and distribution line, the charging / discharging strategy of the electric vehicle load, and the load restoration strategy of the distribution network nodes, thus obtaining the active distribution network restoration scheme. Specifically, the method includes the following steps: Step 1: Based on the spatiotemporal travel characteristics of electric vehicles, establish a charging and discharging model for electric vehicles and charging / swapping stations; Step 1.1: Construct a spatiotemporal demand model for electric vehicle charging and swapping based on the origin-destination matrix using equations (1)-(5): (1) (2) (3) (4) (5) In equations (1)-(5): wheel dis This refers to the average driving distance of an electric vehicle under a fixed operating cycle. t s and t e This refers to the departure and arrival times of electric vehicles within a fixed operating cycle. , and Let be the probability density functions of the electric vehicle's mileage, departure time, and arrival time, respectively, under a fixed operating cycle. μ D , μ S and μ E These are the standard values ​​for the probability distributions of electric vehicle travel mileage, travel start time, and travel end time, respectively. σ D , σ S and σ E These are the standard deviations of the probability distributions for electric vehicle trip mileage, trip start time, and trip end time, respectively. ξ To represent a Boolean variable for day and night, if ξ =1 indicates daytime. ξ =0 indicates nighttime; Ω W and Ω EV They are the set of traffic network nodes and the set of electric vehicles, respectively; Ω T A set of time periods under a fixed period; Trip k For electric vehicles k The set of nodes in the transportation network; Δ l gh For traffic network nodes g To transportation network nodes h The driving distance; Δ T gh For electric vehicles from traffic network nodes g To transportation network nodes h Travel time; p gh,t,t+ΔTgh For electric vehicles from t Time's up t+ Δ T gh Time period determined by traffic network nodes g Drive to the traffic network node h The probability of; a gh,t,t+ΔTgh Fromt Time's up t+ Δ T gh Time period determined by traffic network nodes g Drive to the traffic network node h The number of electric vehicles; SOC k,t For electric vehicles k exist t Remaining battery power for the specified time period; SOC k,t+ΔTgh For electric vehicles k exist t+ Δ T gh Remaining battery power for the specified time period; χ k For electric vehicles k Electricity consumption per unit distance traveled; For electric vehicles k Battery capacity.

[0012] Equation (1) represents the probability density function of daily mileage obtained by fitting the probability distribution data of daily mileage; Equations (2) and (3) represent the probability density functions of fitting the typical start and end times of electric vehicle travel based on parameters such as working hours and travel habits; Equation (4) represents the probability density function of electric vehicle travel during working hours and travel habits. t Time period determined by traffic network nodes g Drive to the node h The probability calculation method; Equation (5) represents the electric vehicle k exist t Time period determined by traffic network nodes g Drive to the node h The remaining battery power is calculated using the following method.

[0013] Step 1.2: Construct the charging and discharging model of the electric vehicle using equations (6)-(14): (6) (7) (8) (9) (10) In equations (6)-(10): Ω BSS It is a collection of electric vehicle charging and battery swapping stations in an active distribution network; δ k,t For electric vehicles k exist t An auxiliary Boolean variable describing the remaining battery power over a given time period; M and εThese are the two parameters used for linearization; SOC th This represents the minimum remaining battery power of an electric vehicle. For electric vehicles k exist t Is there a need for battery swapping during certain periods? =1 indicates a need for battery swapping. =0 indicates no need for battery swapping; for t Electric vehicles during the time period k At charging and swapping stations m Is it charging? for t Electric vehicles during the time period k At charging and swapping stations m Is it in a discharge state? b m,k,t for t Electric vehicles during the time period k Is it located at a battery swapping station? m .

[0014] Equations (6)-(8) state that the remaining battery power of any electric vehicle at any given time period should not be less than the minimum remaining battery power of the electric vehicle, where the parameters... M We need to select a large number, such as 999999, parameter ε A small number, such as 0.00001, needs to be selected; Equation (9) indicates that the battery swapping demand of electric vehicles can only be generated at the charging and swapping station at the current location; Equation (10) indicates that electric vehicles can only discharge at the charging and swapping station at the current location when there is no battery swapping demand.

[0015] (11) (12) (13) (14) In equations (11)-(14): for t Time-of-use charging and battery swapping stations m The number of fully charged batteries inside. for t -1 Period Charging and Swapping Station m The number of fully charged batteries inside; for t Time-of-use charging and battery swapping stations m The number of newly added fully charged batteries; for t Time-of-use charging and battery swapping stations m The number of batteries that need to be charged. fort -1 Period Charging and Swapping Station m The number of batteries that need to be charged; for t Time-of-use charging and battery swapping stations m The number of batteries in a discharged state; t C The number of time periods required to fully charge the battery; for t - t C Electric vehicles during the time period k At charging and swapping stations m Is it charging?

[0016] Equation (11) represents t Time-of-use charging and battery swapping stations m The method for calculating the number of fully charged batteries; Equation (12) represents t Time-of-use charging and battery swapping stations m The calculation method for the number of batteries that need to be charged; Equation (13) represents t Time-of-use charging and battery swapping stations m The method for calculating the number of batteries in a discharged state; Equation (13) represents t Time-of-use charging and battery swapping stations m The method for calculating the number of batteries in a charging state.

[0017] Step 1.3: Construct the charging and discharging model of the charging and battery swapping station using equations (15)-(17): (15) (16) (17) In equations (15)-(17): for t Time-of-use charging and battery swapping stations m Discharge power to the active distribution network, when When it is negative, it means t Time-of-use charging and battery swapping stations m Obtain electrical energy from the active distribution network to charge electric vehicle loads; For charging and battery swapping stations m Maximum discharge power; P BaC and P BaD The charging and discharging power of electric vehicle batteries.

[0018] Equation (15) represents t Time-of-use charging and battery swapping stations mThe charging and discharging power that generates electrical energy interaction with the distribution network should be less than the maximum power; Equation (16) indicates t Time-of-use charging and battery swapping stations m The calculation method for charging / discharging power to the distribution network; Equation (17) indicates that the number of fully charged batteries in any charging / swapping station at any time period should be greater than zero.

[0019] Step 2: Establish a dynamic islanding operation model based on loop radiation elimination, including: islanding model, active distribution network power flow model, and operational constraints of the active distribution network; Step 2.1: Construct an islanding model for the active distribution network using equations (18)-(26): (18) (19) (20) (twenty one) (twenty two) (twenty three) (twenty four) In equations (18)-(24): Ω DG Ω is the set of nodes in an active distribution network that are equipped with distributed generation sources. B and Ω L It is the set of nodes and the set of distribution lines in an active distribution network; S A collection of distribution islands; Ω loop For the collection of loops in an active distribution network; x i,t,s For nodes in an active distribution network i exist t The recovery status during the period, if x i,t,s =1 indicates restoration; if x i,t,s =0 indicates that it has not been restored; y ij,t,s For nodes in an active distribution network i With nodes j The power distribution lines between ij exist t The recovery status during the period, if y ij,t,s =1 indicates restoration; if y ij,t,s =0 indicates that it has not been restored; s-root For deploying distributed power sources with black-start capability in distribution islands s Potential root nodes of the distribution network; xs-root,t,s For nodes in an active distribution network s-root exist t Is the time period treated as a distribution island? s The root node; | l |For the ring road l The number of power distribution lines in the system.

[0020] Equation (18) indicates that a distribution network node containing distributed generation must be assigned to a distribution island; Equation (19) indicates that a regular distribution network node may not be assigned to a distribution island; Equation (20) indicates that each distribution island contains at least one distribution network containing distributed generation; Equations (21) and (22) indicate the distribution lines ij and the nodes at both ends i and nodes j They must be assigned to the same distribution island; Equation (23) indicates that the difference between the number of nodes and the number of lines in any distribution island is 1, thus ensuring the radial topology of the distribution island; Equation (24) indicates that all loops in any distribution island are disconnected.

[0021] (25) (26) In equations (25)-(26): and For nodes in an active distribution network i and power distribution lines ij exist t The actual recovery status during the time period; Equation (25) indicates that a distribution network node is in a recovery state as long as it is assigned to any distribution island; Equation (26) indicates that a distribution line is in a recovery state as long as it is assigned to any distribution island.

[0022] Step 2.2: Construct an active distribution network power flow model based on branch power flow using equations (27)-(31): (27) (28) (29) (30) (31) In equations (27)-(31): BBS( i For nodes in the active distribution network i A collection of interconnected charging and battery swapping stations; and These are nodes in an active distribution network. i Distributed power sources at the locationt The active and reactive power output during each time period. and These are nodes in an active distribution network. i exist t Reactive load and active load during a given time period; κ ij,t For power distribution lines ij exist t Failure probability over a given period; and For nodes in an active distribution network i exist t The active and reactive power of electricity restored during the time period; and They are power distribution lines ij exist t Time period is determined by nodes i To the node j The active and reactive power transmitted; and They are power distribution lines ij exist t Time period is determined by nodes z To the node i The active and reactive power transmitted; for t Time-of-use power distribution lines juice The square of the current in the medium; R ij and X ij They are power distribution lines ij Resistance and reactance; V i,t and V j,t They are respectively t Nodes in a time-sensitive active distribution network i and nodes j The square of the voltage; I ij,t for t Time-of-use power distribution lines ij The square of the current in the medium; Equation (27) represents the node balance equation for active power in the distribution network; Equation (28) represents the node balance equation for reactive power in the distribution network; Equations (29)-(31) represent the power flow constraints of the distribution network after second-order cone relaxation.

[0023] Step 2.3: Construct the operating constraints of the active distribution network using equations (32)-(31): (32) (33) (34) (35) In equations (32)-(35): and These are nodes in an active distribution network. i The maximum active and reactive power that the distributed power source at the location can output; and These are nodes in an active distribution network. i Distributed power sources at the location t The active and reactive power output during the -1 time period; and These are nodes in an active distribution network. i The ramp rate of active and reactive power output of the distributed power source at the location; Equations (32) and (33) indicate that the changes in the active and reactive power output of distributed power sources should meet the capacity constraints; Equations (34) and (35) indicate that the changes in the active and reactive power output of distributed power sources should meet the ramp rate restrictions. (36) (37) (38) (39) In equations (36)-(39): For power distribution lines ij The maximum apparent power that it can withstand; U min and U max These represent the minimum and maximum values ​​of node voltage in an active distribution network.

[0024] Equations (36) and (37) indicate that only power distribution lines in the recovery state can transmit active and reactive power; Equation (38) indicates that the apparent power of a power distribution line should be less than the line capacity; Equation (39) indicates that the voltage of a power distribution network node in the recovery state should meet the amplitude constraint.

[0025] Step 3: Based on the charging and discharging model and the dynamic islanding model, establish an active distribution network recovery model that considers electric vehicle load and islanding operation; Step 3.1: With the goal of minimizing power outage load, number of switching operations, and distribution island size, construct the objective function of the active distribution network recovery model using equation (40): (40) In equation (40): Ω S_close and ΩS_open These are respectively the set of sectionalizing switches and the set of tie switches in an active distribution network; ϖ loss , ϖ sw and ϖ sca These are the objective function weighting coefficients for power outage load, number of switching operations, and distribution island size, respectively. w i For nodes in an active distribution network i The load weighting coefficient; in equation (40) w i It can be generated by nodes in the active distribution network i The importance of the local power load to national economic production is determined by this.

[0026] Step 3.2: Construct power distribution line fault rate constraints using equations (41)-(44): (41) (42) (43) (44) In equations (41)-(44): m ij and C ij For power distribution lines ij Mass per unit length and specific heat capacity; τ ij,t For power distribution lines ij exist t Operating temperature during the specified time period; μ and A These are the temperature coefficient of resistance and the convective heat dissipation coefficient; τ ref and τ env The actual ambient temperature and the rated ambient temperature; For power distribution lines ij exist t The conductor diameter expansion rate over a given period; and For power distribution lines ij The initial conductor radius and in t The amount of conductor diameter expansion during the time period; v wind and p rain For wind speed and probability of rainfall; and For power distribution lines ij Horizontal and vertical load parameters; For power distribution lines ij Design load; a 1 , a 2 , b 1 , b 2 and b 3 There are 5 constant coefficients; Equation (41) represents the distribution line conductor expansion rate equation that takes into account the current heating effect, ambient temperature, wind speed and precipitation factors; Equation (42) represents the calculation method of the distribution line conductor expansion rate; Equation (43) represents the calculation method of the distribution line diameter considering the expansion effect; Equation (44) represents the calculation method of the line fault rate considering the distribution line expansion effect.

[0027] Step 3.3: Construct the standby constraints of the active distribution network using equations (45) and (46): (45) (46) In equations (45)-(46): γ The reserve rate is the reserve rate of the active distribution network. Equation (45) means that the active power output of the restored distributed generation in any distribution island should meet the reserve rate requirement while supplying active power to the restored nodes; Equation (46) means that the reactive power output of the restored distributed generation in any distribution island should meet the reserve rate requirement while supplying reactive power to the restored nodes.

[0028] Step 4: Use the commercial solver CPLEX to solve the active distribution network recovery model to obtain the distribution network recovery scheme, including: the recovery sequence of each node and distribution line of the distribution network, the charging and discharging strategy of electric vehicle loads, and the load recovery strategy of distribution network nodes.

[0029] In this embodiment, an electronic device includes a memory and a processor. The memory stores a program that supports the processor in executing the above-described active power distribution network restoration method, and the processor is configured to execute the program stored in the memory.

[0030] In this embodiment, a computer-readable storage medium stores a computer program, which, when executed by a processor, performs the steps of the above-described active power distribution network restoration method.

Claims

1. An active distribution network restoration method considering electric vehicles and islanding, characterized in that, The procedure is as follows: Step 1: Based on the spatiotemporal travel characteristics of electric vehicles, establish a charging and discharging model for electric vehicles and charging / swapping stations; Step 2: Establish a dynamic islanding operation model based on loop radiation elimination, including: islanding model, active distribution network power flow model, and operational constraints of the active distribution network; Step 3: Based on the charging and discharging model and the dynamic islanding model, establish an active distribution network recovery model that considers electric vehicle load and islanding operation; Step 4: Use the commercial solver CPLEX to solve the active distribution network recovery model to obtain the distribution network recovery scheme, including: the recovery sequence of each node and distribution line of the distribution network, the charging and discharging strategy of electric vehicle loads, and the load recovery strategy of distribution network nodes.

2. The active distribution network restoration method according to claim 1, characterized in that, Step one is to proceed as follows: Step 1.1: Construct a spatiotemporal demand model for electric vehicle charging and swapping based on the origin-destination matrix using equations (1)-(5): (1) (2) (3) (4) (5) In equations (1)-(5): rou dis This refers to the average driving distance of an electric vehicle under a fixed operating cycle. t s and t e This refers to the departure and arrival times of electric vehicles within a fixed operating cycle. , and Let be the probability density functions of the electric vehicle's mileage, departure time, and arrival time, respectively, under a fixed operating cycle. μ D , μ S and μ E These are the standard values ​​for the probability distributions of electric vehicle travel mileage, travel start time, and travel end time, respectively. σ D , σ S and σ E These are the standard deviations of the probability distributions for electric vehicle trip mileage, trip start time, and trip end time, respectively. ξ To represent a Boolean variable for day and night, if ξ =1 indicates daytime. ξ =0 indicates nighttime; Ω W and Ω EV They are the set of traffic network nodes and the set of electric vehicles, respectively; Ω T A set of time periods under a fixed period; Trip k For electric vehicles k The set of nodes in the transportation network; Δ l gh For traffic network nodes g To transportation network nodes h The driving distance; Δ T gh For electric vehicles from traffic network nodes g To transportation network nodes h Travel time; p gh,t,t+ΔTgh For electric vehicles from t Time's up t+ Δ T gh Time period determined by traffic network nodes g Drive to the traffic network node h The probability of; a gh,t,t+ΔTgh From t Time's up t+ Δ T gh Time period determined by traffic network nodes g Drive to the traffic network node h The number of electric vehicles; SOC k,t For electric vehicles k exist t Remaining battery power for the specified time period; SOC k,t+ΔTgh For electric vehicles k exist t+ Δ T gh Remaining battery power for the specified time period; χ k For electric vehicles k Electricity consumption per unit distance traveled; For electric vehicles k Battery capacity; Step 1.2: Construct the charging and discharging model of the electric vehicle using equations (6)-(14): (6) (7) (8) (9) (10) In equations (6)-(10): Ω BSS It is a collection of electric vehicle charging and battery swapping stations in an active distribution network; δ k,t For electric vehicles k exist t An auxiliary Boolean variable describing the remaining battery power over a given time period; M and ε These are the two parameters used for linearization; SOC th This represents the minimum remaining battery power of an electric vehicle. For electric vehicles k exist t Is there a need for battery swapping during certain periods? =1 indicates a need for battery swapping. =0 indicates no need for battery swapping; for t Electric vehicles during the time period k At charging and swapping stations m Is it charging? for t Electric vehicles during the time period k At charging and swapping stations m Is it in a discharge state? b m,k,t for t Electric vehicles during the time period k Is it located at a battery swapping station? m ; (11) (12) (13) (14) In equations (11)-(14): for t Time-of-use charging and battery swapping stations m The number of fully charged batteries inside. for t -1 Period Charging and Swapping Station m The number of fully charged batteries inside; for t Time-of-use charging and battery swapping stations m The number of newly added fully charged batteries; for t Time-of-use charging and battery swapping stations m The number of batteries that need to be charged. for t -1 Period Charging and Swapping Station m The number of batteries that need to be charged; for t Time-of-use charging and battery swapping stations m The number of batteries in a discharged state; t C The number of time periods required to fully charge the battery; for t - t C Electric vehicles during the time period k At charging and swapping stations m Is it charging? Step 1.3: Construct the charging and discharging model of the charging and battery swapping station using equations (15)-(17): (15) (16) (17) In equations (15)-(17): for t Time-of-use charging and battery swapping stations m Discharge power to the active distribution network, when When it is negative, it means t Time-of-use charging and battery swapping stations m Obtain electrical energy from the active distribution network to charge electric vehicle loads; For charging and battery swapping stations m Maximum discharge power; P BaC and P BaD The charging and discharging power of electric vehicle batteries.

3. The active distribution network restoration method according to claim 2, characterized in that, Step two is to proceed as follows: Step 2.1: Construct an islanding model for the active distribution network using equations (18)-(26): (18) (19) (20) (21) (22) (23) (24) In equations (18)-(24): Ω DG Ω is the set of nodes in an active distribution network that are equipped with distributed generation sources. B and Ω L It is the set of nodes and the set of distribution lines in an active distribution network; S A collection of distribution islands; Ω loop For the collection of loops in an active distribution network; x i,t,s For nodes in an active distribution network i exist t The recovery status during the period, if x i,t,s =1 indicates restoration; if x i,t,s =0 indicates that it has not been restored; y ij,t,s For nodes in an active distribution network i With nodes j The power distribution lines between ij exist t The recovery status during the period, if y ij,t,s =1 indicates restoration; if y ij,t,s =0 indicates that it has not been restored; s-root For deploying distributed power sources with black-start capability in distribution islands s Potential root nodes of the distribution network; x s-root,t,s For nodes in an active distribution network s-root exist t Is the time period treated as a distribution island? s The root node; | l |For the ring road l The number of power distribution lines in the system; (25) (26) In equations (25)-(26): and For nodes in an active distribution network i and power distribution lines ij exist t The actual recovery status during the time period; Step 2.2: Construct an active distribution network power flow model based on branch power flow using equations (27)-(31): (27) (28) (29) (30) (31) In equations (27)-(31): BBS( i (to connect with nodes in the active distribution network) i A collection of interconnected charging and battery swapping stations; and These are nodes in an active distribution network. i Distributed power sources at the location t The active and reactive power output during each time period. and These are nodes in an active distribution network. i exist t Reactive load and active load during a given time period; κ ij,t For power distribution lines ij exist t Failure probability over a given period; and For nodes in an active distribution network i exist t The active and reactive power of electricity restored during the time period; and They are power distribution lines ij exist t Time period is determined by nodes i To the node j The active and reactive power transmitted; and They are power distribution lines ij exist t Time period is determined by nodes z To the node i The active and reactive power transmitted; for t Time-of-use power distribution lines zi The square of the current in the medium; R ij and X ij They are power distribution lines ij Resistance and reactance; V i,t and V j,t They are respectively t Nodes in a time-sensitive active distribution network i and nodes j The square of the voltage; I ij,t for t Time-of-use power distribution lines ij The square of the current in the medium; Step 2.3: Construct the operating constraints of the active distribution network using equations (32)-(31): (32) (33) (34) (35) In equations (32)-(35): and These are nodes in an active distribution network. i The maximum active and reactive power that the distributed power source at the location can output; and These are nodes in an active distribution network. i Distributed power sources at the location t The active and reactive power output during the -1 time period; and These are nodes in an active distribution network. i The ramp rate of active and reactive power output of the distributed power source at the location; (36) (37) (38) (39) In equations (36)-(39): For power distribution lines ij The maximum apparent power that it can withstand; U min and U max These represent the minimum and maximum values ​​of node voltage in an active distribution network.

4. The active distribution network restoration method according to claim 3, characterized in that, Step three is to proceed as follows: Step 3.1: With the goal of minimizing power outage load, number of switching operations, and distribution island size, construct the objective function of the active distribution network recovery model using equation (40): (40) In equation (40): Ω S_close and Ω S_open These are respectively the set of sectionalizing switches and the set of tie switches in an active distribution network; ϖ loss , ϖ sw and ϖ sca These are the objective function weighting coefficients for power outage load, number of switching operations, and distribution island size, respectively. w i For nodes in an active distribution network i The load weighting coefficient; Step 3.2: Construct power distribution line fault rate constraints using equations (41)-(44): (41) (42) (43) (44) In equations (41)-(44): m ij and C ij For power distribution lines ij Mass per unit length and specific heat capacity; τ ij,t For power distribution lines ij exist t Operating temperature during the specified time period; μ and A These are the temperature coefficient of resistance and the convective heat dissipation coefficient; τ ref and τ env The actual ambient temperature and the rated ambient temperature; For power distribution lines ij exist t The conductor diameter expansion rate over a given period; and For power distribution lines ij The initial conductor radius and in t The amount of conductor diameter expansion during the time period; v wind and p rain For wind speed and probability of rainfall; and For power distribution lines ij Horizontal and vertical load parameters; For power distribution lines ij Design load; a 1 , a 2 , b 1 , b 2 and b 3 It has 5 constant coefficients; Step 3.3: Construct the standby constraints of the active distribution network using equations (45) and (46): (45) (46) In equations (45)-(46): γ This refers to the reserve rate of the active distribution network.

5. An electronic device, comprising a memory and a processor, characterized in that, The memory is used to store a program that supports the processor in executing the active distribution network restoration method according to any one of claims 1-4, and the processor is configured to execute the program stored in the memory.

6. A computer-readable storage medium storing a computer program thereon, characterized in that, When the computer program is run by the processor, it performs the steps of the active power distribution network restoration method according to any one of claims 1-5.

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