Electro-thermal coupling system cooperative load recovery method and system considering electric vehicle aggregation charging and discharging

Abstract

The invention discloses an electric-thermal coupling system cooperative load recovery method and system considering electric vehicle aggregation charging and discharging. The method comprises the following steps: step 1, establishing an objective function with the minimum load loss amount of the electric-thermal integrated energy system; 2, constructing an electric-thermal coupling system collaborative load recovery model, wherein the model comprises load recovery stage network topology constraint, power system steady-state operation constraint and regional heat supply system steady-state operation constraint; and step 3, solving by using an interior point method to obtain output of a power distribution network, a regional heat supply system network topology, a transformer substation, a distributed power supply and a cogeneration unit in the electric-thermal coupling system. The method provided by the invention can be practically applied to formulating a toughness improvement strategy of the park-level electro-thermal coupling system, fully exploits the flexibility of an electric vehicle cluster, reduces the overall load loss amount of the system, enhances the ability of the system to cope with sudden faults, and ensures the safe and stable operation of the system.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of operation and control of multi-energy flow coupling systems, and particularly relates to an electric-thermal coupling system collaborative load recovery method and system considering aggregated charging and discharging of electric vehicles. BACKGROUND

[0002] Energy security is one of the most important securities, however, with the increasingly close coupling of electricity, heat, gas and other multi-energy flows in urban integrated energy systems, large-scale cascading failures have increased dramatically, and large-area energy supply interruption accidents have occurred frequently. Therefore, it is urgent to enhance the recovery capability of urban energy systems to deal with low-probability and high-impact emergencies, and to provide support for ensuring urban energy security.

[0003] As the main consumer of urban energy, electric vehicles have natural flexibility potential. The energy demand of electric vehicles under catastrophic conditions is highly coupled with urban integrated energy systems, and deeply affects the recovery period of urban load; at the same time, with the wide application of vehicle-to-grid technology in the automobile field, electric vehicles gradually evolve from one-way energy consumers to two-way energy producers and consumers, which can significantly alleviate the energy supply pressure of urban integrated energy systems. Under extreme conditions, the potential flexible adjustment space and energy supply capacity of electric vehicles can accelerate the self-healing process of the city.

[0004] In summary, it is urgent to tap the collaborative adjustment potential of electric vehicles under different dynamic characteristics, improve the energy supply recovery capability of the city after the disaster, and promote the development of high-resilience urban integrated energy systems. SUMMARY

[0005] The purpose of the present application is to fill the gaps in the prior art, and to provide an electric-thermal coupling system collaborative load recovery method and system considering aggregated charging and discharging of electric vehicles, so as to fully tap the natural flexibility of electric vehicles and improve the energy supply recovery capability of urban integrated energy systems, and to provide support for the safe and stable operation of resilient cities.

[0006] To achieve the purpose of the present application, the technical solutions provided by the present application are as follows:

[0007] First aspect

[0008] The present application provides an electric-thermal coupling system collaborative load recovery method considering aggregated charging and discharging of electric vehicles, comprising the following steps:

[0009] Step 1: Establishing an objective function of minimizing the loss of electric and thermal loads of the electric-thermal integrated energy system:

[0010]

[0011] wherein, represents the number of lost electric and thermal loads of node j, a j , bj T represents the weight of electrical and thermal loads. i Indicates the duration of the quarantine phase, T r p represents the duration of the long-term load recovery phase. s k represents the probability of failure scenario s occurring; S represents all failure scenarios; bus ,k nd This represents the set of nodes in the power distribution network and heating network; t represents time.

[0012] Step 2: Construct a collaborative load recovery model for the electric-thermal coupled system, including network topology constraints, power system steady-state operation constraints, and district heating system steady-state operation constraints during the load recovery phase;

[0013] Step 3: Using the interior point method, under the objective function given in Step 1 and according to the constraints given in Step 2, solve for the distribution network, district heating system network topology, substation, distributed power output, and combined heat and power unit output within the electric-thermal coupling system.

[0014] Second aspect

[0015] This application provides a collaborative load recovery system for an electro-thermal coupling system considering the combined charging and discharging of electric vehicles. The system uses the above-mentioned method and includes the following units: an objective function establishment unit, a model construction unit, and a solution unit.

[0016] The objective function establishment unit is used to establish the objective function that minimizes the load loss of the integrated electric-thermal energy system.

[0017]

[0018] in, Indicates the quantity of electrical and heat load losses at node j, a j b j T represents the weight of electrical and thermal loads. i Indicates the duration of the quarantine phase, T r p represents the duration of the long-term load recovery phase. s k represents the probability of failure scenario s occurring; S represents all failure scenarios; bus ,k nd This represents the set of nodes in the power distribution network and heating network; t represents time.

[0019] The model building unit is used to build a collaborative load recovery model for an electric-thermal coupled system, including network topology constraints, power system steady-state operation constraints, and district heating system steady-state operation constraints during the load recovery phase.

[0020] The solution unit is used to solve for the distribution network, district heating system network topology, substation, distributed power output, and combined heat and power unit output within the electric-thermal coupling system, based on the objective function and constraints, using the interior point method and the aforementioned objective function.

[0021] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0022] The strategy proposed in this application considers the coordinated reconfiguration of the distribution network and the heating network, incorporating the flexibility of electric vehicles to improve the load recovery level of the electric-thermal coupling system. Compared to considering distribution network reconfiguration in isolation, heating network reconfiguration can optimize the heating system's heating structure to match changes in the distribution system network topology, effectively suppressing the spread of faults between systems; through intelligent charge and discharge control participating in system power balance, it fully taps the dispatchable potential of electric vehicles, improving the system's load recovery level. The method provided in this application can be practically applied to the formulation of resilience enhancement strategies for campus-level electric-thermal coupling systems, fully leveraging the flexibility of electric vehicle clusters, reducing the overall system load loss, enhancing the system's ability to cope with sudden faults, and ensuring the safe and stable operation of the system. Attached Figure Description

[0023] Figure 1 This is a schematic flowchart of a method for coordinated load recovery of an electro-thermal coupling system considering the combined charging and discharging of electric vehicles, provided in an embodiment of this application. Detailed Implementation

[0024] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0025] like Figure 1 As shown, this embodiment provides a method for coordinated load recovery of an electro-thermal coupling system considering the combined charging and discharging of electric vehicles, including the following steps:

[0026] Step 1: Establish the objective function for minimizing the load shedding of the integrated electric-thermal energy system:

[0027]

[0028] in, Indicates the quantity of electrical and heat load losses at node j, a j b j T represents the weight of electrical and thermal loads. i Indicates the duration of the quarantine phase, T r p represents the duration of the long-term load recovery phase.s k represents the probability of failure scenario s occurring; S represents all failure scenarios; bus ,k nd This represents the set of nodes in the power distribution network and heating network; t represents time.

[0029] Step 2: Construct a collaborative load recovery model for the electric-thermal coupled system, including network topology constraints, power system steady-state operation constraints, and district heating system steady-state operation constraints during the load recovery phase;

[0030] The network topology constraints during the load recovery phase are expressed as follows:

[0031] (1) Constraints during the fault isolation phase, as follows:

[0032]

[0033] In the formula, k pipe k represents the set of transmission lines in a power distribution system. line This represents the collection of heating pipes in a district heating system; This represents the set of CHP units in the power distribution system; This represents the collection of CHP units in a heating system; f ij,s Indicates the fault status of heating pipelines / power transmission lines (i,j); μ ij,0 Indicates the initial state of the heating pipeline / power transmission line (i,j); χ i,s,t Indicates the region (fault zone / non-fault zone) to which node i belongs in the power distribution / heating system at stage t; χ m,c,t and χ n,c,t This indicates whether the CHP unit in the power distribution / heating system is faulty at time t. ij,0 Indicates the switch configuration status of heating pipelines / power transmission lines (i,j); μ ij,s,t This indicates the connection status of the heating pipeline / power transmission line (i,j) at stage t;

[0034] (2) To ensure the safety of maintenance personnel, the switches / valves configured in the fault area can only be used for fault recovery after maintenance of the pipelines / lines in the fault area. Switches / valves in non-fault areas can be used directly for fault recovery.

[0035]

[0036] In the formula, k pipe k represents the set of transmission lines in a power distribution system. line Indicates the collection of heating pipes in a district heating system; f ij,s Indicates the fault status of heating pipelines / power transmission lines (i,j); z ij,t This represents the initial state of the heating pipeline / power transmission line (i,j);

[0037] (3) The network topology of the power distribution system / heating system must meet the radial constraint:

[0038]

[0039] Where, n ij n s Indicates the number of nodes and root nodes in the distribution network / heating network, a ji,s,t As an auxiliary variable, a represents the parent-child relationship between the nodes at both ends of the line (j, i). ji,s,t =1 indicates that node j is the parent node of node i, d j,s,t This indicates the load status of node j.

[0040] The steady-state operation constraints of the power system include the following:

[0041] (1) Nodal power balance equations:

[0042]

[0043] Where, p j,s,t q j,s,t p represents the active and reactive power injected into node j; js,s,t q js,s,t Represents the active and reactive power flowing from node j to s; r ij x ij Represents the resistance and reactance of line (i,j); This indicates the active and reactive power injected into DGj; This indicates the active and reactive power injected into CHP unit j; This indicates the active and reactive power consumed by SOPj. This represents the active and reactive power consumed by load j. This represents the active and reactive power loss of load j;

[0044] (2) Branch capacity constraints: The power transmitted by an open / faulted transmission line is zero, and the power transmitted by a closed transmission line is not allowed to exceed its limit.

[0045]

[0046] Among them, u i,s,t This represents the square of the voltage value at node j. This represents the upper and lower limits of the transmission capacity of line (i,j);

[0047] (3) Power constraints for cogeneration units: The active and reactive power of cogeneration units in the fault zone is zero, while the active and reactive power of cogeneration units in the non-fault zone are between the set upper and lower limits for safe operation.

[0048]

[0049] in, This indicates the upper and lower limits of the active power output of CHP unit j; This indicates the upper and lower limits of the reactive power output of CHP unit j;

[0050] (4) Distributed power source power constraints: The active and reactive power of the distributed power source in the fault zone is zero, and the active and reactive power of the distributed power source in the non-fault zone is between the set safe operating upper and lower limits:

[0051]

[0052] in, This represents the upper and lower limits of the active power output of the distributed power source j. This represents the upper and lower limits of the reactive power output of the distributed power source j;

[0053] (5) Power Constraints of Parked Electric Vehicles: Charging stations are installed in underground parking lots to meet the travel needs of electric vehicle users. To fully utilize the flexibility of electric vehicle batteries within the parking lot, a mathematical model for variable power charging and discharging of electric vehicles is constructed:

[0054]

[0055] In the formula, Let be the state of charge value of the h-th electric vehicle at time t; κ is the self-loss coefficient; η c and η d These are the charging efficiency and discharging efficiency of electric vehicle batteries, respectively. and These represent the charging power and discharging power of the electric vehicle battery, respectively; Δt is the scheduling time step; E B The capacity of the electric vehicle battery; Boolean decision variables; These are the maximum charging power and maximum discharging power of the electric vehicle's battery, respectively. Each electric vehicle must meet the user's expectations when it leaves.

[0056] (6) Node load loss constraint: All electrical loads in the fault zone will be lost, and the node load loss in the non-fault zone is less than or equal to the node load:

[0057]

[0058] (7) The node voltage of a closed transmission line must meet the branch power flow constraints:

[0059]

[0060] The steady-state operation constraints of the district heating system include the following:

[0061] (1) Thermal power constraint of cogeneration units:

[0062]

[0063] in, This indicates the upper and lower limits of the output thermal power of the combined heat and power unit j. V represents the heat output power of a combined heat and power (CHP) unit. j This represents the upper and lower limits of the ratio of electrical output power to thermal output power of a combined heat and power (CHP) unit. The formula indicates that the thermal output of the CHP unit is zero within the fault zone, and between the set safe operating upper and lower limits within the non-fault zone.

[0064] (2) Heat pump thermal power constraint in district heating system: The heat pump thermal power is zero in the fault zone, and the heat pump thermal power in the non-fault zone is between the set safe operating upper and lower limits:

[0065]

[0066] in, This indicates the upper and lower limits of the heat pump j's output heat power;

[0067] (3) Constraints on the heat loss equation of the heating network pipeline in the district heating system:

[0068]

[0069] in, This refers to the usable thermal power of the circulating water at the beginning of the heating network pipeline, which is the difference between the thermal power contained in the working fluid flow at the beginning of the supply water network and the thermal power contained in the corresponding working fluid flow in the return water network. This refers to the heat power loss of circulating water at the beginning and end of the pipeline.

[0070] (4) Pipeline transmission capacity constraint: The heat power transmitted by a disconnected / faulty pipeline is zero, and the heat power transmitted by a closed pipeline is not allowed to exceed its limit.

[0071]

[0072] in, This is the upper limit of the usable thermal power of the circulating water at the beginning and end of the pipeline;

[0073] (5) Nodal thermal balance constraints:

[0074]

[0075] in, This indicates the output heat power of heat station k. This represents the heat power of load j and the heat power lost;

[0076] (6) Node load loss constraint: All electrical loads in the fault zone will be lost, and the node load loss in the non-fault zone is less than or equal to the node load:

[0077]

[0078] Step 3: Using the interior point method, under the objective function given in Step 1 and according to the constraints given in Step 2, solve for the distribution network, district heating system network topology, substation, distributed power output, and combined heat and power unit output within the electric-thermal coupling system.

[0079] In addition, this embodiment also provides a collaborative load recovery system for an electro-thermal coupling system considering the combined charging and discharging of electric vehicles. The method used in the system includes the following units: an objective function establishment unit, a model construction unit, and a solution unit.

[0080] The objective function establishment unit is used to establish the objective function that minimizes the load loss of the integrated electric-thermal energy system.

[0081]

[0082] in, Indicates the quantity of electrical and heat load losses at node j, a j b j T represents the weight of electrical and thermal loads. i Indicates the duration of the quarantine phase, T r p represents the duration of the long-term load recovery phase. s k represents the probability of failure scenario s occurring; S represents all failure scenarios; bus ,k nd This represents the set of nodes in the power distribution network and heating network; t represents time.

[0083] The model building unit is used to build a collaborative load recovery model for an electric-thermal coupled system, including network topology constraints, power system steady-state operation constraints, and district heating system steady-state operation constraints during the load recovery phase.

[0084] The network topology constraints during the load recovery phase are expressed as follows:

[0085] (1) Constraints during the fault isolation phase, as follows:

[0086]

[0087]

[0088] In the formula, k pipek represents the set of transmission lines in a power distribution system. line This represents the collection of heating pipes in a district heating system; This represents the set of CHP units in the power distribution system; This represents the collection of CHP units in a heating system; f ij,s Indicates the fault status of heating pipelines / power transmission lines (i,j); μ ij,0 Indicates the initial state of the heating pipeline / power transmission line (i,j); χ i,s,t Indicates the region (fault zone / non-fault zone) to which node i belongs in the power distribution / heating system at stage t; χ m,c,t and χ n,c,t This indicates whether the CHP unit in the power distribution / heating system is faulty at time t. ij,0 Indicates the switch configuration status of heating pipelines / power transmission lines (i,j); μ ij,s,t This indicates the connection status of the heating pipeline / power transmission line (i,j) at stage t;

[0089] (2) To ensure the safety of maintenance personnel, the switches / valves configured in the fault area can only be used for fault recovery after maintenance of the pipelines / lines in the fault area. Switches / valves in non-fault areas can be used directly for fault recovery.

[0090]

[0091] In the formula, k pipe k represents the set of transmission lines in a power distribution system. line Indicates the collection of heating pipes in a district heating system; f ij,s Indicates the fault status of heating pipelines / power transmission lines (i,j); z ij,t This represents the initial state of the heating pipeline / power transmission line (i,j);

[0092] (3) The network topology of the power distribution system / heating system must meet the radial constraint:

[0093]

[0094]

[0095] Where, n ij n s Indicates the number of nodes and root nodes in the distribution network / heating network, a ji,s,t As an auxiliary variable, a represents the parent-child relationship between the nodes at both ends of the line (j, i). ji,s,t =1 indicates that node j is the parent node of node i, d j,s,t This indicates the load status of node j.

[0096] The steady-state operation constraints of the power system include the following:

[0097] (1) Nodal power balance equations:

[0098]

[0099] Where, p j,s,t q j,s,t p represents the active and reactive power injected into node j; js,s,t q js,s,t Represents the active and reactive power flowing from node j to s; r ij x ij Represents the resistance and reactance of line (i,j); This indicates the active and reactive power injected into DGj; This indicates the active and reactive power injected into CHP unit j; This indicates the active and reactive power consumed by SOPj. This represents the active and reactive power consumed by load j. This represents the active and reactive power loss of load j;

[0100] (2) Branch capacity constraints: The power transmitted by an open / faulted transmission line is zero, and the power transmitted by a closed transmission line is not allowed to exceed its limit.

[0101]

[0102] Among them, u i,s,t This represents the square of the voltage value at node j. This represents the upper and lower limits of the transmission capacity of line (i,j);

[0103] (3) Power constraints for cogeneration units: The active and reactive power of cogeneration units in the fault zone is zero, while the active and reactive power of cogeneration units in the non-fault zone are between the set upper and lower limits for safe operation.

[0104]

[0105] in, This indicates the upper and lower limits of the active power output of CHP unit j; This indicates the upper and lower limits of the reactive power output of CHP unit j;

[0106] (4) Distributed power source power constraints: The active and reactive power of the distributed power source in the fault zone is zero, and the active and reactive power of the distributed power source in the non-fault zone is between the set safe operating upper and lower limits:

[0107]

[0108] in, This represents the upper and lower limits of the active power output of the distributed power source j. This represents the upper and lower limits of the reactive power output of the distributed power source j;

[0109] (5) Power Constraints of Parked Electric Vehicles: Charging stations are installed in underground parking lots to meet the travel needs of electric vehicle users. To fully utilize the flexibility of electric vehicle batteries within the parking lot, a mathematical model for variable power charging and discharging of electric vehicles is constructed:

[0110]

[0111] In the formula, Let be the state of charge value of the h-th electric vehicle at time t; κ is the self-loss coefficient; η c and η d These are the charging efficiency and discharging efficiency of electric vehicle batteries, respectively. and These represent the charging power and discharging power of the electric vehicle battery, respectively; Δt is the scheduling time step; E B The capacity of the electric vehicle battery; Boolean decision variables; These are the maximum charging power and maximum discharging power of the electric vehicle's battery, respectively. Each electric vehicle must meet the user's expectations when it leaves.

[0112] (6) Node load loss constraint: All electrical loads in the fault zone will be lost, and the node load loss in the non-fault zone is less than or equal to the node load:

[0113]

[0114] (7) The node voltage of a closed transmission line must meet the branch power flow constraints:

[0115]

[0116] The steady-state operation constraints of the district heating system include the following:

[0117] (1) Thermal power constraint of cogeneration units:

[0118]

[0119] in, This indicates the upper and lower limits of the output thermal power of the combined heat and power unit j. This represents the heat output power of a combined heat and power (CHP) unit, v j This represents the upper and lower limits of the ratio of electrical output power to thermal output power of a combined heat and power (CHP) unit. The formula indicates that the thermal output of the CHP unit is zero within the fault zone, and between the set safe operating upper and lower limits within the non-fault zone.

[0120] (2) Heat pump thermal power constraint in district heating system: The heat pump thermal power is zero in the fault zone, and the heat pump thermal power in the non-fault zone is between the set safe operating upper and lower limits:

[0121]

[0122] in, This indicates the upper and lower limits of the heat pump j's output heat power;

[0123] (3) Constraints on the heat loss equation of the heating network pipeline in the district heating system:

[0124]

[0125] in, This refers to the usable thermal power of the circulating water at the beginning of the heating network pipeline, which is the difference between the thermal power contained in the working fluid flow at the beginning of the supply water network and the thermal power contained in the corresponding working fluid flow in the return water network. This refers to the heat power loss of circulating water at the beginning and end of the pipeline.

[0126] (4) Pipeline transmission capacity constraint: The heat power transmitted by a disconnected / faulty pipeline is zero, and the heat power transmitted by a closed pipeline is not allowed to exceed its limit.

[0127]

[0128]

[0129] in, This is the upper limit of the usable thermal power of the circulating water at the beginning and end of the pipeline;

[0130] (5) Nodal thermal balance constraints:

[0131]

[0132] in, This indicates the output heat power of heat station k. This represents the heat power of load j and the heat power lost;

[0133] (6) Node load loss constraint: All electrical loads in the fault zone will be lost, and the node load loss in the non-fault zone is less than or equal to the node load:

[0134]

[0135] The solution unit is used to solve for the distribution network, district heating system network topology, substation, distributed power output, and combined heat and power unit output within the electric-thermal coupling system, based on the objective function and constraints, using the interior point method and the aforementioned objective function.

[0136] This strategy considers the coordinated reconfiguration of the distribution network and the heating network, incorporating the flexibility of electric vehicles to improve the load recovery level of the electric-thermal coupled system. Compared to considering distribution network reconfiguration in isolation, heating network reconfiguration can optimize the heating system's heating structure to match changes in the distribution system network topology, effectively suppressing the spread of faults between systems. Through intelligent charge and discharge control participating in system power balancing, it fully taps the dispatchable potential of electric vehicles, improving the system's load recovery level. This method can be practically applied to the formulation of resilience enhancement strategies for campus-level electric-thermal coupled systems, fully leveraging the flexibility of electric vehicle clusters, reducing the overall system load loss, enhancing the system's ability to cope with sudden faults, and ensuring the safe and stable operation of the system.

[0137] Finally, it should be noted that the above embodiments are merely illustrative and explanatory of the present invention, and are not intended to limit the present invention to the scope of the described embodiments. Furthermore, those skilled in the art will understand that the present invention is not limited to the above embodiments, and many more variations and modifications can be made based on the teachings of the present invention, all of which fall within the scope of protection claimed by the present invention.

Claims

1. A method for coordinated load recovery of an electro-thermal coupling system considering the combined charging and discharging of electric vehicles, characterized in that, Includes the following steps: Step 1: Establish the objective function for minimizing the load shedding of the integrated electric-thermal energy system: in, Indicates the quantity of electrical and heat load losses at node j, a j b j T represents the weight of electrical and thermal loads. i Indicates the duration of the quarantine phase, T r p represents the duration of the long-term load recovery phase. s k represents the probability of failure scenario s occurring; S represents all failure scenarios; bus ,k nd This represents the set of nodes in the power distribution network and heating network; t represents time. Step 2: Construct a collaborative load recovery model for the electric-thermal coupled system, including network topology constraints, power system steady-state operation constraints, and district heating system steady-state operation constraints during the load recovery phase; Step 3: Using the interior point method, under the objective function given in Step 1 and according to the constraints given in Step 2, solve for the distribution network, district heating system network topology, substation, distributed power output, and combined heat and power unit output within the electric-thermal coupling system.

2. The method for coordinated load recovery of an electro-thermal coupling system considering the combined charging and discharging of electric vehicles according to claim 1, characterized in that, The network topology constraints during the load recovery phase are expressed as follows: (1) Constraints during the fault isolation phase, as follows: In the formula, k pipe k represents the set of transmission lines in a power distribution system. line This represents the collection of heating pipes in a district heating system; This represents the set of CHP units in the power distribution system; This represents the collection of CHP units in a heating system; f ij,s Indicates the fault status of heating pipelines / power transmission lines (i,j); μ ij,0 Indicates the initial state of the heating pipeline / power transmission line (i,j); χ i,s,t Indicates the region (fault zone / non-fault zone) to which node i belongs in the power distribution / heating system at stage t; χ m,c,t and χ n,c,t This indicates whether the CHP unit in the power distribution / heating system is faulty at time t. ij,0 Indicates the switch configuration status of heating pipelines / power transmission lines (i,j); μ ij,s,t This indicates the connection status of the heating pipeline / power transmission line (i,j) at stage t; (2) To ensure the safety of maintenance personnel, the switches / valves configured in the fault area can only be used for fault recovery after maintenance of the pipelines / lines in the fault area. Switches / valves in non-fault areas can be used directly for fault recovery. (1-f ij,s )(z ij,s,t-1 -s ij,0 )≤z ij,s,t ≤(1-f ij,s )(z ij,s,t-1 +s ij,0 ), In the formula, k pipe k represents the set of transmission lines in a power distribution system. line Indicates the collection of heating pipes in a district heating system; f ij,s Indicates the fault status of heating pipelines / power transmission lines (i,j); z ij,t This represents the initial state of the heating pipeline / power transmission line (i,j); (3) The network topology of the power distribution system / heating system must meet the radial constraint: |a ji,s,t |≤z ij,s,t n ij , Where, n ij n s Indicates the number of nodes and root nodes in the distribution network / heating network, a ji,s,t As an auxiliary variable, a represents the parent-child relationship between the nodes at both ends of the line (j, i). ji,s,t =1 indicates that node j is the parent node of node i, d j,s,t This indicates the load status of node j.

3. The method for coordinated load recovery of an electro-thermal coupling system considering the combined charging and discharging of electric vehicles according to claim 2, characterized in that, The steady-state operation constraints of the power system include the following: (1) Nodal power balance equations: Where, p j,s,t q j,s,t p represents the active and reactive power injected into node j; js,s,t q js,s,t Represents the active and reactive power flowing from node j to s; r ij x ij Represents the resistance and reactance of line (i,j); This indicates the active and reactive power injected into DGj; This indicates the active and reactive power injected into CHP unit j; This indicates the active and reactive power consumed by SOPj. This represents the active and reactive power consumed by load j. This represents the active and reactive power loss of load j; (2) Branch capacity constraints: The power transmitted by an open / faulted transmission line is zero, and the power transmitted by a closed transmission line is not allowed to exceed its limit. ||2p ij,s,t 2q ij,s,t l ij,s,t -u i,s,t ||2≤l ij,s,t +u i,s,t , Among them, u i,s,t This represents the square of the voltage value at node j. This represents the upper and lower limits of the transmission capacity of line (i,j); (3) Power constraints for cogeneration units: The active and reactive power of cogeneration units in the fault zone is zero, while the active and reactive power of cogeneration units in the non-fault zone are between the set upper and lower limits for safe operation. in, This indicates the upper and lower limits of the active power output of CHP unit j; This indicates the upper and lower limits of the reactive power output of CHP unit j; (4) Distributed power source power constraints: The active and reactive power of the distributed power source in the fault zone is zero, and the active and reactive power of the distributed power source in the non-fault zone is between the set safe operating upper and lower limits: in, This represents the upper and lower limits of the active power output of the distributed power source j. This represents the upper and lower limits of the reactive power output of the distributed power source j; (5) Power Constraints of Parked Electric Vehicles: Charging stations are installed in underground parking lots to meet the travel needs of electric vehicle users. To fully utilize the flexibility of electric vehicle batteries within the parking lot, a mathematical model for variable power charging and discharging of electric vehicles is constructed: In the formula, Let be the state of charge value of the h-th electric vehicle at time t; κ is the self-loss coefficient; η c and η d These are the charging efficiency and discharging efficiency of electric vehicle batteries, respectively. and These represent the charging power and discharging power of the electric vehicle battery, respectively; Δt is the scheduling time step; E B The capacity of the electric vehicle battery; Boolean decision variables; These are the maximum charging power and maximum discharging power of the electric vehicle's battery, respectively. Each electric vehicle must meet the user's expectations when it leaves. (6) Node load loss constraint: All electrical loads in the fault zone will be lost, and the node load loss in the non-fault zone is less than or equal to the node load: (7) The node voltage of a closed transmission line must meet the branch power flow constraints:

4. The method for coordinated load recovery of an electro-thermal coupling system considering the combined charging and discharging of electric vehicles according to claim 3, characterized in that, The steady-state operation constraints of the district heating system include the following: (1) Thermal power constraint of cogeneration units: in, This indicates the upper and lower limits of the output thermal power of the combined heat and power unit j. This represents the heat output power of a combined heat and power (CHP) unit, v j This represents the upper and lower limits of the ratio of electrical output power to thermal output power of a combined heat and power (CHP) unit. The formula indicates that the thermal output of the CHP unit is zero within the fault zone, and between the set safe operating upper and lower limits within the non-fault zone. (2) Heat pump thermal power constraint in district heating system: The heat pump thermal power is zero in the fault zone, and the heat pump thermal power in the non-fault zone is between the set safe operating upper and lower limits: in, This indicates the upper and lower limits of the heat pump j's output heat power; (3) Constraints on the heat loss equation of the heating network pipeline in the district heating system: in, This refers to the usable thermal power of the circulating water at the beginning of the heating network pipeline, which is the difference between the thermal power contained in the working fluid flow at the beginning of the supply water network and the thermal power contained in the corresponding working fluid flow in the return water network. This refers to the heat power loss of circulating water at the beginning and end of the pipeline. (4) Pipeline transmission capacity constraint: The heat power transmitted by a disconnected / faulty pipeline is zero, and the heat power transmitted by a closed pipeline is not allowed to exceed its limit. in, This is the upper limit of the usable thermal power of the circulating water at the beginning and end of the pipeline; (5) Nodal thermal balance constraints: in, This indicates the output heat power of heat station k. This represents the heat power of load j and the heat power lost; (6) Node load loss constraint: All electrical loads in the fault zone will be lost, and the node load loss in the non-fault zone is less than or equal to the node load:

5. A coordinated load recovery system for an electro-thermal coupling system considering the combined charging and discharging of electric vehicles, said system using the method as described in any one of claims 1-4, characterized in that, It includes the following units: objective function establishment unit, model construction unit, and solution unit; The objective function establishment unit is used to establish the objective function that minimizes the load loss of the integrated electric-thermal energy system. in, Indicates the quantity of electrical and heat load losses at node j, a j b j T represents the weight of electrical and thermal loads. i Indicates the duration of the quarantine phase, T r p represents the duration of the long-term load recovery phase. s k represents the probability of failure scenario s occurring; S represents all failure scenarios; bus ,k nd This represents the set of nodes in the power distribution network and heating network; t represents time. The model building unit is used to build a collaborative load recovery model for an electric-thermal coupled system, including network topology constraints, power system steady-state operation constraints, and district heating system steady-state operation constraints during the load recovery phase. The solution unit is used to solve for the distribution network, district heating system network topology, substation, distributed power output, and combined heat and power unit output within the electric-thermal coupling system, based on the objective function and constraints, using the interior point method and the aforementioned objective function.

6. A coordinated load recovery system for an electro-thermal coupling system considering the combined charging and discharging of electric vehicles, as described in claim 5, is characterized in that... The network topology constraints during the load recovery phase are expressed as follows: (1) Constraints during the fault isolation phase, as follows: In the formula, k pipe k represents the set of transmission lines in a power distribution system. line This represents the collection of heating pipes in a district heating system; This represents the set of CHP units in the power distribution system; This represents the collection of CHP units in a heating system; f ij,s Indicates the fault status of heating pipelines / power transmission lines (i,j); μ ij,0 Indicates the initial state of the heating pipeline / power transmission line (i,j); χ i,s,t Indicates the region (fault zone / non-fault zone) to which node i belongs in the power distribution / heating system at stage t; χ m,c,t and χ n,c,t This indicates whether the CHP unit in the power distribution / heating system is faulty at time t. ij,0 Indicates the switch configuration status of heating pipelines / power transmission lines (i,j); μ ij,s,t This indicates the connection status of the heating pipeline / power transmission line (i,j) at stage t; (2) To ensure the safety of maintenance personnel, the switches / valves configured in the fault area can only be used for fault recovery after maintenance of the pipelines / lines in the fault area. Switches / valves in non-fault areas can be used directly for fault recovery. (1-f ij,s )(z ij,s,t-1 -s ij,0 )≤z ij,s,t ≤(1-f ij,s )(z ij,s,t-1 +s ij,0 ), In the formula, k pipe k represents the set of transmission lines in a power distribution system. line Indicates the collection of heating pipes in a district heating system; f ij,s Indicates the fault status of heating pipelines / power transmission lines (i,j); z ij,t This represents the initial state of the heating pipeline / power transmission line (i,j); (3) The network topology of the power distribution system / heating system must meet the radial constraint: |a ji,s,t |≤z ij,s,t n ij , Where, n ij n s Indicates the number of nodes and root nodes in the distribution network / heating network, a ji,s,t As an auxiliary variable, a represents the parent-child relationship between the nodes at both ends of the line (j, i). ji,s,t =1 indicates that node j is the parent node of node i, d j,s,t This indicates the load status of node j.

7. A coordinated load recovery system for an electro-thermal coupling system considering the combined charging and discharging of electric vehicles, as described in claim 6, is characterized in that... The steady-state operation constraints of the power system include the following: (1) Nodal power balance equations: Where, p j,s,t q j,s,t p represents the active and reactive power injected into node j; js,s,t q js,s,t Represents the active and reactive power flowing from node j to s; r ij x ij Represents the resistance and reactance of line (i,j); This indicates the active and reactive power injected into DGj; This indicates the active and reactive power injected into CHP unit j; This indicates the active and reactive power consumed by SOPj. This represents the active and reactive power consumed by load j. This represents the active and reactive power loss of load j; (2) Branch capacity constraints: The power transmitted by an open / faulted transmission line is zero, and the power transmitted by a closed transmission line is not allowed to exceed its limit. ||2p ij,s,t 2q ij,s,t l ij,s,t -u i,s,t ||2≤l ij,s,t +u i,s,t , Among them, u i,s,t This represents the square of the voltage value at node j. This represents the upper and lower limits of the transmission capacity of line (i,j); (3) Power constraints for cogeneration units: The active and reactive power of cogeneration units in the fault zone is zero, while the active and reactive power of cogeneration units in the non-fault zone are between the set upper and lower limits for safe operation. in, This indicates the upper and lower limits of the active power output of CHP unit j; This indicates the upper and lower limits of the reactive power output of CHP unit j; (4) Distributed power source power constraints: The active and reactive power of the distributed power source in the fault zone is zero, and the active and reactive power of the distributed power source in the non-fault zone is between the set safe operating upper and lower limits: in, This represents the upper and lower limits of the active power output of the distributed power source j. This represents the upper and lower limits of the reactive power output of the distributed power source j; (5) Power Constraints of Parked Electric Vehicles: Charging stations are installed in underground parking lots to meet the travel needs of electric vehicle users. To fully utilize the flexibility of electric vehicle batteries within the parking lot, a mathematical model for variable power charging and discharging of electric vehicles is constructed: In the formula, Let be the state of charge value of the h-th electric vehicle at time t; κ is the self-loss coefficient; η c and η d These are the charging efficiency and discharging efficiency of electric vehicle batteries, respectively. and These represent the charging power and discharging power of the electric vehicle battery, respectively; Δt is the scheduling time step; E B The capacity of the electric vehicle battery; Boolean decision variables; These are the maximum charging power and maximum discharging power of the electric vehicle's battery, respectively. Each electric vehicle must meet the user's expectations when it leaves. (6) Node load loss constraint: All electrical loads in the fault zone will be lost, and the node load loss in the non-fault zone is less than or equal to the node load: (7) The node voltage of a closed transmission line must meet the branch power flow constraints:

8. A coordinated load recovery system for an electro-thermal coupling system considering the combined charging and discharging of electric vehicles, as described in claim 7, is characterized in that, The steady-state operation constraints of the district heating system include the following: (1) Thermal power constraint of cogeneration units: in, This indicates the upper and lower limits of the output thermal power of the combined heat and power unit j. This represents the heat output power of a combined heat and power (CHP) unit, v j This represents the upper and lower limits of the ratio of electrical output power to thermal output power of a combined heat and power (CHP) unit. The formula indicates that the thermal output of the CHP unit is zero within the fault zone, and between the set safe operating upper and lower limits within the non-fault zone. (2) Heat pump thermal power constraint in district heating system: The heat pump thermal power is zero in the fault zone, and the heat pump thermal power in the non-fault zone is between the set safe operating upper and lower limits: in, This indicates the upper and lower limits of the heat pump j's output heat power; (3) Constraints on the heat loss equation of the heating network pipeline in the district heating system: in, This refers to the usable thermal power of the circulating water at the beginning of the heating network pipeline, which is the difference between the thermal power contained in the working fluid flow at the beginning of the supply water network and the thermal power contained in the corresponding working fluid flow in the return water network. This refers to the heat power loss of circulating water at the beginning and end of the pipeline. (4) Pipeline transmission capacity constraint: The heat power transmitted by a disconnected / faulty pipeline is zero, and the heat power transmitted by a closed pipeline is not allowed to exceed its limit. in, This is the upper limit of the usable thermal power of the circulating water at the beginning and end of the pipeline; (5) Nodal thermal balance constraints: in, This indicates the output heat power of heat station k. This represents the heat power of load j and the heat power lost; (6) Node load loss constraint: All electrical loads in the fault zone will be lost, and the node load loss in the non-fault zone is less than or equal to the node load:

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