A method for improving comprehensive energy resilience of ports considering electric container trucks connected to the power grid

Abstract

The present invention provides a method for improving the comprehensive energy resilience of ports considering the connection of electric container trucks to the power grid, and relates to a circuit device or system for power supply or distribution. The method comprises the following steps: S1, when the port power system is disconnected from the external power grid, an emergency power support period is taken; S2, within the emergency power support period, every second time period is taken as a scheduling time node, and the dispatchable distributed resources in each time node are compared to see whether they meet the load demand of the port, until they are met; S3, a two-layer optimization architecture with the lowest scheduling cost of comprehensive energy equipment and the smallest overall load reduction is constructed; S4, an electric container truck scheduling plan is formulated; S5, the two-layer optimization architecture with the lowest scheduling cost of comprehensive energy equipment and the smallest overall load reduction is solved. The present invention can save electric energy to the greatest extent for the optimal scheduling of the shortest scheduling distance of mobile energy storage in the port area, and more electric energy is fed back to the power grid, which has the best guarantee effect on the overall load recovery of the power grid.

Description

Technical Field

[0001] The present invention relates to a circuit device or system for power supply or distribution, and in particular to a method for improving the comprehensive energy resilience of a port by taking into account the connection of electric container trucks to a power grid. Background Art

[0002] Frequent natural disasters have caused great damage to the operation of the power distribution network, seriously threatening energy security and the stable development of society. Especially for ports, as an important infrastructure for urban development, port microgrids have large energy demand and dense demand points. Once the power system is interrupted by natural disasters, resulting in insufficient power supply and paralysis of loading and unloading equipment, the port will face huge economic losses. In order to better reduce the losses caused by natural disasters to the port power system, with the implementation of mobile energy storage technology and the introduction of various clean energy sources into the port power system, it is necessary to consider the deployment and utilization of various distributed resources in the port to achieve resilience improvement. Summary of the invention

[0003] The present invention provides a method for improving the comprehensive energy resilience of a port by taking into account the connection of electric container trucks to a power grid, so as to at least solve the above technical problems existing in the prior art.

[0004] According to a first aspect of the present invention, a method for improving the comprehensive energy resilience of a port considering electric container trucks connected to a power grid is provided, comprising the following steps:

[0005] S1, when the port power system is disconnected from the external power grid, the first time period is taken as the emergency power support period;

[0006] S2, within the emergency power support period, taking every second time period as a scheduling time node, comparing whether the schedulable distributed resources within each time node meet the load demand of the port until the load demand is met;

[0007] S3, construct a two-layer optimization framework with the lowest comprehensive energy equipment dispatching cost and the smallest overall load reduction, including the upper target model of the resilience improvement strategy, the lower load reduction model of the resilience improvement strategy, the electric container truck dispatching model, and the electric container truck charging and discharging model;

[0008] S4, formulate a dispatching plan for electric container trucks;

[0009] S5, solving the two-layer optimization framework of minimizing the integrated energy equipment dispatching cost and minimizing the overall load reduction.

[0010] In certain embodiments of the present invention, the dispatchable distributed resources include the electric energy stored in the electrochemical energy storage system in the integrated energy system, the electric energy generated by the wind turbines and photovoltaic equipment at the scheduling time node, and the electric energy stored in the electric container truck that is connected to the charging pile for charging.

[0011] In some embodiments of the present invention, the upper target model of the resilience enhancement strategy is as follows: The total cost of port power system operation under the resilience enhancement strategy The cost of purchasing hydrogen , Equipment operating costs of integrated energy systems and load reduction costs It consists of three parts;

[0012] (1)

[0013] (2)

[0014] (3)

[0015] (4)

[0016] In formula (1): is the purchase price of hydrogen, It is the set of time points when the port power system is disconnected from the external power grid. is the hydrogen purchase rate at time t;

[0017] In formula (2): The operation and maintenance costs of photovoltaic power generation, is the photovoltaic power generation power at time t, is the unit power operation and maintenance cost of wind turbine, is the fan operating power at time t, is the unit power operation and maintenance cost of the electrochemical energy storage system, is the charging power of the electrochemical energy storage system at time t, is the discharge operating power of the electrochemical energy storage system at time t, is the unit power operation and maintenance cost of the flexible direct current, is the operating power of the flexible DC at time t, is the fuel cell unit power operation and maintenance cost, is the fuel cell operating power at time t;

[0018] In formula (3), Reduce costs per unit load, is the load reduction of the substation at time t, Assemble for the port substation.

[0019] In certain embodiments of the present invention, the integrated energy system is modeled, including an electrochemical energy storage system model, an electrolyzer model, a hydrogen storage system model, and a hydrogen fuel cell model.

[0020] In certain embodiments of the present invention, the electrochemical energy storage system model is as follows:

[0021] The upper and lower limits of energy storage power and the change of energy storage capacity at the beginning and end of the energy storage scheduling cycle

[0022] (5)

[0023] (6)

[0024] In the formula, represents the charge of the electrochemical energy storage system at time t, and The corresponding electrochemical energy storage systems are The charging power and discharging power at the moment, and It is the charging efficiency and discharging efficiency of the electrochemical energy storage system; is the interval of scheduling time; is the upper limit of charging power and discharging power of the electrochemical energy storage system; variable and is a 0 / 1 variable, When it is 0, it means not charging. When it is 1, it means charging; When it is 0, it means no discharge. When it is 1, it represents discharge;

[0025] (7)

[0026] In the formula, is the capacity limit of the electrochemical energy storage system; Represents the amount of electricity stored in the electrochemical energy storage system at time t; It is the lowest state of charge of the electrochemical energy storage system; It is the highest state of charge of the electrochemical energy storage system.

[0027] In certain embodiments of the present invention, the electrolytic cell model is as follows:

[0028] The electrolyzer uses electric current to decompose water to produce hydrogen and oxygen. The power supply from the power grid to the electrolyzer has the following relationship:

[0029] (8)

[0030] Where: is the operating power of the electrolyzer at time t, is the power input to the electrolyzer from the electric energy converted from renewable energy at time t, is the efficiency of the electrolyzer in utilizing grid electricity;

[0031] Electrolyzer hydrogen production power The hydrogen production rate of the electrolyzer The relationship is as follows:

[0032] (9)

[0033] (10)

[0034] Where: is the hydrogen production coefficient of the electrolyzer; is the Faraday efficiency; is the number of electrolyzers in the electrolyzer array, is the number of moles of electrons transferred in the hydrogen reaction; is the Faraday constant; A constant terminal voltage maintained for the AC / DC converter.

[0035] In certain embodiments of the present invention, the hydrogen storage system model is as follows:

[0036] The hydrogen storage system is used to store the hydrogen generated by the electrolysis of the electric energy converted from clean energy through the electrolyzer. The energy equation stored in the tank is as follows:

[0037] (11)

[0038] Where: is the maximum capacity of the hydrogen storage system, is the hydrogen energy state of the hydrogen storage system at time t; represents the hydrogen production rate of the electrolyzer at time t, is the hydrogen consumption rate at time t, represents the hydrogen purchase rate at time t, Indicates the hydrogen consumption rate of the hydrogen fuel cell;

[0039] The charge state constraint range of hydrogen storage during operation is as shown in formula (12):

[0040] (12)

[0041] Where: and are the lower and upper limits of the equivalent state of charge of the hydrogen storage system, respectively;

[0042] Hydrogen injection rate of hydrogen storage system With restrictions as shown in formula (13):

[0043] (13)

[0044] In the formula, Indicates the upper limit of the hydrogen injection rate of the hydrogen storage system.

[0045] In certain embodiments of the present invention, the hydrogen fuel cell model is as follows:

[0046] When a hydrogen fuel cell outputs hydrogen energy, the hydrogen energy and output power are as shown in formula (14):

[0047] (14)

[0048] Where: is the output power of the hydrogen fuel cell at time t; is the number of moles of electrons transferred in the hydrogen reaction; is Avogadro's constant; is the molar mass of hydrogen; is the number of electrons per coulomb; is the rated output voltage at time t; is the fuel cell conversion efficiency;

[0049] During operation, the operating power of the hydrogen fuel cell needs to meet the following upper and lower limit constraints:

[0050] (15)

[0051] Where: and They are respectively the lower and upper limits of the output power of hydrogen fuel cells.

[0052] In certain embodiments of the present invention, the lower load reduction model of the resilience enhancement strategy is as follows:

[0053] (16)

[0054] (17)

[0055] (18)

[0056] (19)

[0057] (20)

[0058] Where: is the importance weight of the load in the area controlled by each substation, For the substation collection in the port, Represents the node To Node The maximum power flow of the distribution line is Flow to Node , ,otherwise, ; and Represents the slave nodes The collection of nodes pointing outward and inward to the node, Represents the busbar at time t The phase angle at Representative Node To Node The reactance of the distribution line, Represents time t The amount of load reduction on the node.

[0059] In some embodiments of the present invention, the electric container truck scheduling model is as follows:

[0060] Taking the port plane as the object, a two-dimensional coordinate system of the port is established, and the distance between the electric container truck and the charging pile is calculated as follows:

[0061] (twenty one)

[0062] Where m=1, 2, 3...n is the number of electric container trucks in the port area, k=1, 2, 3...a is the number of idle charging piles in the port area; The shortest driving distance from the electric truck to the nearby charging station in each area, , are the horizontal and vertical coordinates of the electric container trucks in each area, , is the horizontal and vertical coordinates of the location of each charging pile, is the relationship variable of the electric container truck from the pth area to the jth area. According to the driving rules of the electric container truck in the port area, the following matrix Decide:

[0063]

[0064] is the variable of the right boundary of the area where the charging pile and electric truck are located, satisfying formula (22)

[0065] (twenty two)

[0066] After obtaining the relative position of the electric container truck and the charging pile by establishing a two-dimensional coordinate system, the working status of each charging pile is read, and the SOC of each electric container truck is read at the same time, which is recorded as (m=1,2,3,…,n), n is the total number of electric container trucks in the port area; The power required for the electric truck to travel to the charging station is calculated as shown in formula (23):

[0067] (twenty three)

[0068] In the formula, It is the amount of electricity from when the electric truck receives the instruction to when it goes to the charging pile. is the shortest path distance for the electric truck to reach the nearest charging station. is the average electric energy consumed per kilometer traveled by the electric container truck, Represents the maximum battery capacity of the electric container truck. It is the battery power level when the electric container truck reaches the charging station.

[0069] In some embodiments of the present invention, the charging and discharging model of the electric container truck is as follows:

[0070] The electric trucks are charged and discharged by charging piles connected to the port power grid. The power of the electric trucks in the port is calculated as follows for each time interval:

[0071] (twenty four)

[0072] (25)

[0073] In the formula, and They represent the charging power flow and discharging power flow of the electric container truck respectively, and They represent the battery charging efficiency and discharging efficiency of the electric container truck respectively. Represents the total energy stored in the battery of each electric container truck at each research time point; and It is a 0-1 variable, indicating the charging and discharging status of the electric container truck;

[0074] During the charging and discharging process, the state of charge cannot exceed the upper and lower limits specified by the battery. The SOC of the electric container truck can be expressed as:

[0075] (26)

[0076] (27)

[0077] In the formula, Indicates the state of charge of the battery of the electric container truck at time node t; and They respectively represent the lower and upper limits of the charge state of the electric container truck during the charging and discharging process.

[0078] Compared with the prior art, the present invention has the following beneficial effects:

[0079] In extreme cases caused by disasters, the port power system is disconnected from the external power grid to form an island. By optimizing the dispatchable distributed resources, the resilience of the port power grid can be effectively improved. The optimal dispatch of the shortest dispatch distance for mobile energy storage in the port area can save energy to the greatest extent, and more energy can be fed back to the power grid, which has the best guarantee effect on the overall load recovery of the power grid. At the same time, the importance of the port load is weighted, and the demand nodes of the first-level load are preferentially connected and supplied, which can provide better protection for the first-level load.

[0080] It should be understood that the contents described in this section are not intended to identify the key or important features of the embodiments of the present invention, nor are they intended to limit the scope of the present invention. Other features of the present invention will become easily understood through the following description. BRIEF DESCRIPTION OF THE DRAWINGS

[0081] The above and other objects, features and advantages of the exemplary embodiments of the present invention will become readily understood by reading the following detailed description with reference to the accompanying drawings, in which several embodiments of the present invention are shown by way of example and not limitation.

[0082] In the drawings, the same or corresponding reference numerals represent the same or corresponding parts.

[0083] Figure 1 A port power system architecture diagram according to an embodiment of the present invention is shown.

[0084] Figure 2 A schematic diagram of driving route planning for an electric container truck in a port area according to an embodiment of the present invention is shown.

[0085] Figure 3 A simulation diagram of improving the toughness of a section of busbar in the first vehicle dispatching scenario of the present invention is shown.

[0086] Figure 4 A simulation diagram of the toughness improvement of a two-section bus in the first vehicle dispatching scenario of the present invention is shown.

[0087] Figure 5 A simulation diagram of the toughness improvement of hydrogen energy flow in the first vehicle dispatching scenario of the present invention is shown.

[0088] Figure 6 A simulation diagram of improving the resilience of the power system in the first vehicle dispatching scenario of the present invention is shown.

[0089] Figure 7 A simulation diagram of improving the toughness of a section of busbar in the second vehicle dispatching scenario of the present invention is shown.

[0090] Figure 8 A simulation diagram of the toughness improvement of a two-section bus in the second vehicle dispatching scenario of the present invention is shown.

[0091] Fig. 9 A simulation diagram of the toughness improvement of hydrogen energy flow in the second vehicle dispatching scenario of the present invention is shown.

[0092] Fig.10 A simulation diagram of improving the resilience of the power system in the second vehicle dispatching scenario of the present invention is shown.

[0093] Fig.11 A simulation diagram of improving the toughness of a section of busbar in the third vehicle dispatching scenario of the present invention is shown.

[0094] Fig.12 A simulation diagram of the toughness improvement of the two-section bus in the third vehicle dispatching scenario of the present invention is shown.

[0095] Fig.13 A simulation diagram of the toughness improvement of hydrogen energy flow in the third vehicle dispatching scenario of the present invention is shown.

[0096] Fig.14 A simulation diagram of improving the resilience of the power system in the third vehicle dispatching scenario of the present invention is shown. DETAILED DESCRIPTION

[0097] In order to make the purpose, features and advantages of the present invention more obvious and easy to understand, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative work are within the scope of protection of the present invention.

[0098] like Figure 1As shown, the port of this embodiment is divided into several areas during the actual production and operation process, and the number of electric container trucks distributed in the port area is positively correlated with the area of ​​the area. The battery capacity of the electric container trucks is equal and the battery capacity state needs to be kept within the specified range. The comprehensive energy of the port includes renewable energy systems, power facilities, electrochemical energy storage, flexible DC interconnection equipment, and hydrogen energy systems. Among them, the renewable energy system includes wind turbines and photovoltaic equipment. Power equipment includes field bridges, quay bridges, ship shore power, street lights, etc. The hydrogen energy system uses electrical energy to decompose water into an electrolyzer, a hydrogen storage system, and a hydrogen fuel cell that converts hydrogen energy into electrical energy. A flexible DC interconnection device 3 connecting a section bus 1 and a section bus 2 is provided in the substation to adjust the energy balance between a section bus 1 and a section bus 2. A section bus 1 and a section bus 2 are distributed in different areas of the port and are respectively connected to an external power grid 4. The entire port is equipped with two wind turbines connected to bus section 1 and bus section 2 respectively, and the electrolyzer, rooftop photovoltaic and electrochemical energy storage are connected to bus section 1. The hydrogen fuel cell is connected to bus section 2. There are 6 charging pile areas in the port area, distributed on bus section 1 and bus section 2, and each area has a total of 5 charging piles available.

[0099] This embodiment provides a method for improving the comprehensive energy resilience of a port considering the connection of an electric container truck to a power grid, including the following steps:

[0100] S1, when the port power system is disconnected from the external power grid, a first time period is taken as an emergency power support period. It is worth mentioning that the first time period can be 2 hours, 3 hours or 4 hours, and 2 hours is preferred in this embodiment.

[0101] S2: During the emergency power support period, every second time period is taken as a scheduling time node to compare whether the schedulable distributed resources in each time node meet the load demand of the port until it is met; similarly, the second time period can be 10 minutes or 15 minutes, and 10 minutes is preferred in this embodiment.

[0102] When the dispatchable distributed resources cannot meet the load demand of the port, the load types covered by the port substation are weighted to represent the importance of the load controlled by the substation.

[0103] In addition, the load demand of the above-mentioned port includes the load demand of the substation on the first bus 1 and the second bus 2. The dispatchable distributed resources include the electric energy stored in the electrochemical energy storage system in the integrated energy system, the electric energy generated by the wind turbine and photovoltaic equipment at the scheduling time node, and the electric energy stored in the electric container truck that is connected to the charging pile for charging.

[0104] S3, constructs a two-layer optimization architecture with the lowest comprehensive energy equipment scheduling cost and the smallest overall load reduction, including the upper target model of the resilience enhancement strategy, the lower load reduction model of the resilience enhancement strategy, the electric container truck scheduling model, and the electric container truck charging and discharging model.

[0105] The following is an introduction to the above-mentioned models one by one.

[0106] The upper-level target model of the resilience improvement strategy is as follows: The total cost of port power system operation under the resilience improvement strategy The cost of purchasing hydrogen , Equipment operating costs of integrated energy systems and load reduction costs It consists of three parts;

[0107] (1)

[0108] (2)

[0109] (3)

[0110] (4)

[0111] In formula (1): is the purchase price of hydrogen, It is the set of time points when the port power system is disconnected from the external power grid. is the hydrogen purchase rate at time t;

[0112] In formula (2): The operation and maintenance costs of photovoltaic power generation, is the photovoltaic power generation power at time t, is the unit power operation and maintenance cost of wind turbine, is the fan operating power at time t, is the unit power operation and maintenance cost of the electrochemical energy storage system, is the charging power of the electrochemical energy storage system at time t, is the discharge operating power of the electrochemical energy storage system at time t, is the unit power operation and maintenance cost of the flexible direct current, is the operating power of the flexible DC at time t, is the fuel cell unit power operation and maintenance cost, is the fuel cell operating power at time t;

[0113] In formula (3), Reduce costs per unit load, is the load reduction of the substation at time t, Assemble for the port substation.

[0114] Formula (4) is the overall operating cost when the port power system and the external power grid are disconnected.

[0115] In this embodiment, the comprehensive energy system is modeled, which mainly includes an electrochemical energy storage system model, an electrolyzer model, a hydrogen storage system model and a hydrogen fuel cell model.

[0116] The electrochemical energy storage system model is as follows:

[0117] The constraints that the electrochemical energy storage system (EESS) needs to meet during operation are shown in equations (5) and (6), including the upper and lower limits of the energy storage power and the change in energy storage capacity at the beginning and end of the energy storage scheduling cycle.

[0118] (5)

[0119] (6)

[0120] In the formula, represents the charge of the electrochemical energy storage system at time t, and The corresponding electrochemical energy storage systems are The charging power and discharging power at the moment, and It is the charging efficiency and discharging efficiency of the electrochemical energy storage system; is the interval of scheduling time; is the upper limit of the charging power and the upper limit of the discharging power of the electrochemical energy storage system; considering that the electrochemical energy storage device cannot be charged and discharged at the same time at any time, the variable and , the variable and is a 0 / 1 variable, When it is 0, it means not charging. When it is 1, it means charging; When it is 0, it means no discharge. When it is 1, it represents discharge; it means that at any time, the electrochemical energy storage system can only be in one of the three states: charging, discharging, or neither charging nor discharging.

[0121] The range of the state of charge of the electrochemical energy storage system during operation is shown in formula (7).

[0122] (7)

[0123] In the formula, is the capacity limit of the electrochemical energy storage system; Represents the amount of electricity stored in the electrochemical energy storage system at time t; It is the lowest state of charge of the electrochemical energy storage system; It is the highest state of charge of the electrochemical energy storage system.

[0124] The electrolyzer model is as follows:

[0125] The electrolyzer uses electric current to decompose water to produce hydrogen and oxygen. The power supply from the power grid to the electrolyzer has the following relationship:

[0126] (8)

[0127] Where: is the operating power of the electrolyzer at time t, is the power input to the electrolyzer from the electric energy converted from renewable energy at time t, is the efficiency of the electrolyzer in utilizing grid electricity;

[0128] Electrolyzer hydrogen production power The hydrogen production rate of the electrolyzer The relationship is as follows:

[0129] (9)

[0130] (10)

[0131] Where: is the hydrogen production coefficient of the electrolyzer; is the Faraday efficiency; is the number of electrolyzers in the electrolyzer array, is the number of moles of electrons transferred in the hydrogen reaction; is the Faraday constant; A constant terminal voltage maintained for the AC / DC converter.

[0132] The hydrogen storage system model is as follows:

[0133] The hydrogen storage system (HESS) is used to store hydrogen generated by electrolysis of electric energy converted from clean energy through an electrolyzer. The energy equation stored in the tank is as shown in equation (11).

[0134] (11)

[0135] Where: is the maximum capacity of the hydrogen storage system, is the hydrogen energy state of the hydrogen storage system at time t; represents the hydrogen production rate of the electrolyzer at time t, is the hydrogen consumption rate at time t, represents the hydrogen purchase rate at time t, Indicates the hydrogen consumption rate of the hydrogen fuel cell;

[0136] The charge state constraint range of hydrogen storage during operation is shown in formula (12).

[0137] (12)

[0138] Where: and are the lower and upper limits of the equivalent state of charge of the hydrogen storage system, respectively;

[0139] Hydrogen injection rate of hydrogen storage system With restrictions as shown in formula (13)

[0140] (13)

[0141] In the formula, Indicates the upper limit of the hydrogen injection rate of the hydrogen storage system.

[0142] The hydrogen fuel cell model is as follows:

[0143] When hydrogen fuel cells output hydrogen energy, they are closely related to the physical parameters of the gas. The hydrogen energy and output power are as shown in formula (14):

[0144] (14)

[0145] Where: is the output power of the hydrogen fuel cell at time t; is the number of moles of electrons transferred in the hydrogen reaction; is Avogadro's constant; is the molar mass of hydrogen; is the number of electrons per coulomb; is the rated output voltage at time t; is the fuel cell conversion efficiency;

[0146] During operation, the operating power of the hydrogen fuel cell needs to meet the following upper and lower limit constraints:

[0147] (15)

[0148] Where: and They are respectively the lower and upper limits of the output power of hydrogen fuel cells.

[0149] The load reduction model of the lower layer of the resilience enhancement strategy is as follows:

[0150] According to the fact that the dispatchable distributed energy in the port area at a certain time point is not enough to fully support the load demand of the port area, measures need to be taken to protect the important load energy demand supporting the port area as much as possible. In this invention, the first consideration is to remove the flexible load, which can support the rigid load of the port to the greatest extent. The DC power flow model is used. Due to its robustness, this model is widely used in transmission systems, distribution systems and vulnerability analysis. The specific model is as follows

[0151] (16)

[0152] (17)

[0153] (18)

[0154] (19)

[0155] (20)

[0156] Where: is the importance weight of the load in the area controlled by each substation, For the substation collection in the port, Represents the node To Node The maximum power flow of the distribution line is Flow to Node , ,otherwise, ; and Represents the slave nodes The collection of nodes pointing outward and inward to the node, Represents the busbar at time t The phase angle at Representative Node To Node The reactance of the distribution line, Represents time t The amount of load reduction on the node.

[0157] The detailed physical explanation of the above constraints is as follows. Formula (16) describes the optimization objective, which is the minimum load shedding assigned according to the load importance of different areas of the port. Formula (17) limits the power flow on the distribution lines of each node of the port to a certain range. Formula (18) and (19) represent the logistics flow equations, which must be satisfied for the load shedding of each node. Formula (20) ensures that the load shedding does not exceed the total load of the node.

[0158] The electric container truck scheduling model is as follows:

[0159] like Figure 2 The figure shows a schematic diagram of the electric container truck of this embodiment having a clear path travel planning during the scheduling process. The charging piles of the port are arranged along the coastline, and each charging area contains five charging piles. In the port, the boundary of the yard is generally divided into multiple areas. When the electric container truck is disconnected from the external power grid during the operation of the port, it is regarded as a mobile energy storage. Port container trucks are divided into internal container trucks and external container trucks. The internal container trucks are driven by electricity, that is, electric container trucks (Electric container trucks, referred to as ECT), which mainly serve the port, and travel between the yard area and the quay crane area for ship loading and unloading. The external container trucks transport containers from the yard to various logistics centers outside the terminal. In order to ensure the efficiency and safety of port operations, the driving roads of the external container trucks and the internal container trucks are separated and planned inside the port. The electric container trucks on the yard side travel from west to east, and can travel in both directions near the quay crane side.

[0160] Based on the above port truck driving rules, the port plane is used as the object to establish a port two-dimensional coordinate system. Since electric trucks can only travel in one direction from left to right in the port yard, if the electric trucks and charging piles are located in different areas, the distance between them will be calculated differently. The distance between the electric trucks and the charging piles is calculated as follows:

[0161] (twenty one)

[0162] Where m=1, 2, 3...n is the number of electric container trucks in the port area, k=1, 2, 3...a is the number of idle charging piles in the port area; The shortest driving distance from the electric truck to the nearby charging station in each area, , are the horizontal and vertical coordinates of the electric container trucks in each area, , is the horizontal and vertical coordinates of the location of each charging pile, is the relationship variable of the electric container truck from the pth area to the jth area. According to the driving rules of the electric container truck in the port area, the following matrix Decide:

[0163]

[0164] is the variable of the right boundary of the area where the charging pile and electric truck are located, satisfying formula (22)

[0165] (twenty two)

[0166] After obtaining the relative position of the electric container truck and the charging pile by establishing a two-dimensional coordinate system, the working status of each charging pile is read, and the SOC of each electric container truck is read at the same time, which is recorded as (m=1,2,3,…,n), n is the total number of electric container trucks in the port area; The power required for the electric truck to travel to the charging station is calculated as shown in formula (23):

[0167] (twenty three)

[0168] In the formula, It is the amount of electricity from when the electric truck receives the instruction to when it goes to the charging pile. is the shortest path distance for the electric truck to reach the nearest charging station. is the average electric energy consumed per kilometer traveled by the electric container truck. Represents the maximum battery capacity of the electric container truck. It is the battery power level when the electric container truck reaches the charging station.

[0169] The charging and discharging model of electric container truck is as follows:

[0170] The electric container truck is charged and discharged through the charging pile connected to the port power grid. The power of the electric container truck in the port is calculated as follows for each time interval (24). It is impossible for any electric container truck to charge and discharge at the same time, and the condition of formula (25) must be met:

[0171] (twenty four)

[0172] (25)

[0173] In the formula, and They represent the charging power flow and discharging power flow of the electric container truck respectively, and They represent the battery charging efficiency and discharging efficiency of the electric container truck respectively. Represents the total energy stored in the battery of each electric container truck at each research time point; and It is a 0-1 variable, indicating the charging and discharging status of the electric container truck;

[0174] During the charging and discharging process, the state of charge cannot exceed the upper and lower limits specified by the battery. The SOC of the electric container truck can be expressed as:

[0175] (26)

[0176] (27)

[0177] In the formula, Represents the maximum battery capacity of the electric container truck. Indicates the state of charge of the battery of the electric container truck at time node t; and They represent the lower and upper limits of the state of charge of the electric truck during the charging and discharging process. Lower than This means that the electric container truck is not suitable for dispatching and realizing power support.

[0178] S4, formulate a dispatching plan for electric container trucks. This embodiment includes the following three dispatching plans.

[0179] Solution 1: An optimization strategy for maximum energy coupling between the mobile energy storage system and the power grid is used to dispatch electric container trucks to the nearest charging pile to transmit electricity to the port power grid node.

[0180] Solution 2: Optimization strategy for coupling mobile energy storage systems with key loads of the power grid. Consider the importance of building substations connected to charging piles in ports and the distance between vehicles and substations. Dispatch electric container trucks to charging piles connected to important load substations and in the target substation coverage area. The implementation method of this patent sets a weight coefficient between the distance between the electric container truck and the charging pile. The larger the weight value, the more important the load controlled by the substation. The comprehensive weight coefficient takes into account the distance between the vehicle and the substation, thereby delivering electric energy to key load nodes.

[0181]

[0182] It is the distance weight between the electric container truck and the charging pile. The specific values ​​are 1 for the first-level load weight, 0.8 for the second-level load weight, and 0.6 for the third-level load weight.

[0183] Solution 3: Mobile energy storage system identification allocation mechanism and grid load coupling optimization strategy. Electric container trucks are arranged to go to fixed charging piles according to vehicle numbers to transmit electricity to port grid nodes.

[0184] S5, using MATLAB to call the Yalmip toolbox and Gurobi solver to solve the two-layer optimization architecture of minimizing the integrated energy equipment scheduling cost and minimizing the overall load reduction.

[0185] In other embodiments, it also includes S6, using resilience evaluation indicators to evaluate the utilization of distributed resources in the integrated energy system and the overall resilience improvement optimization strategy by adding three vehicle scheduling schemes. The resilience indicators used are defined as follows:

[0186] 1) Average loss rate of primary load during the toughness improvement period

[0187] (28)

[0188] In the formula, It is the load reduction amount in each time period in the area covered by the primary load substation.

[0189] 2) Average survival rate of primary load during the toughness improvement period

[0190] (29)

[0191] In the formula, It is the total load demand in each period within the area covered by the primary load substation under normal circumstances.

[0192] 3) Overall load loss rate during the toughness improvement period

[0193] (30)

[0194] In the formula, It refers to the load reduction in the area covered by all substations in the port area at different time periods.

[0195] 4) Average survival rate of overall load during the toughness improvement period

[0196] (31)

[0197] In the formula, It is the total load demand in each period within the area covered by all substations in the port area under normal circumstances.

[0198] The simulation results of using the above three schemes to coordinate the resilience improvement of the port integrated energy system are as follows: Figures 3 to 14 shown.

[0199] Under the optimized scheduling of the above three schemes, the port’s resilience improvement effect under extreme conditions is shown in Table 1.

[0200] Table 1

[0201]

[0202] In the case of only considering the distance between the electric truck and the charging pile, the first-level load loss rate is 37.3858kW / min, the first-level load average survival rate is 94.1576%, the overall load loss rate is 132.7301kW / min, and the overall load average survival rate is 88.3757%. In the second scheme, the importance of the load covered by the port substation and the distance between the electric truck and the target charging pile are considered. The first-level load loss rate is 35.9601kW / min, the first-level load average recovery rate is 95.5148%, the overall load loss rate is 136.3781kW / min, and the overall load average survival rate is 88.0433%. In the third scheme, only the initial assignment of the charging pile position of the vehicle is considered. The first-level load loss rate is 41.8916kW / min, the first-level load average survival rate is 93.466%, the overall load loss rate is 144.8336kW / min, and the overall load average survival rate is 87.2913%.

[0203] The simulation results show that when the wind and solar power output is greater than the load at a certain time point, it will be charged through the electric energy storage system or the electric container truck connected to the charging pile. Between the first and second busbars, part of the second and third load demands will be eliminated according to the importance, and the energy supply of the first load will be met first, and the electric energy will be connected between the first and second busbars through flexible DC interconnection. The optimal dispatching of the shortest dispatching distance for mobile energy storage in the port area can save energy to the greatest extent, and more energy will be fed back to the power grid, which will have the best guarantee effect on the overall load recovery of the power grid. After considering the weight, the demand node of the first load is accessed first and energy is supplied, which can provide better guarantee for the first load. Through the designated scheme access, since the mobile energy storage goes to various locations of the port with the task work and does not work in a fixed area, more electricity is lost in the state of cross-regional dispatching, resulting in poor recovery guarantee of the overall load of the port.

[0204] It should be understood that the various forms of processes shown above can be used to reorder, add or delete steps. For example, the steps described in the present invention can be executed in parallel, sequentially or in different orders, as long as the desired results of the technical solution of the present invention can be achieved, and this document does not limit this.

[0205] In addition, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include at least one of the features. In the description of the present invention, the meaning of "plurality" is two or more, unless otherwise clearly and specifically defined.

[0206] The above is only a specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Any person skilled in the art can easily think of changes or substitutions within the technical scope disclosed by the present invention, which should be included in the protection scope of the present invention. Therefore, the protection scope of the present invention should be based on the protection scope of the claims.

Claims

1. A method for improving the comprehensive energy resilience of a port considering the connection of electric container trucks to the power grid, characterized in that: The following steps are involved: S1, when the port power system is disconnected from the external power grid, the first time period is taken as the emergency power support period; S2, within the emergency power support period, taking every second time period as a scheduling time node, comparing whether the dispatchable distributed resources within each scheduling time node meet the load demand of the port until the load demand is met; S3, construct a two-layer optimization framework with the lowest comprehensive energy equipment dispatching cost and the smallest overall load reduction, including the upper target model of the resilience improvement strategy, the lower load reduction model of the resilience improvement strategy, the electric container truck dispatching model, and the electric container truck charging and discharging model; S4, formulate a dispatching plan for electric container trucks; S5, solving a two-layer optimization framework for minimizing the comprehensive energy equipment dispatching cost and minimizing the overall load reduction; The dispatchable distributed resources include the electric energy stored in the electrochemical energy storage system in the integrated energy system, the electric energy generated by the wind turbine and photovoltaic equipment at the dispatching time node, and the electric energy stored in the electric container truck that is connected to the charging pile for charging; The upper-level target model of the resilience improvement strategy is as follows: The total cost of port power system operation under the resilience improvement strategy The cost of purchasing hydrogen , Equipment operating costs of integrated energy systems and load reduction costs It consists of three parts; (1) (2) (3) (4) In formula (1): is the purchase price of hydrogen, It is the set of time points when the port power system is disconnected from the external power grid. is the hydrogen purchase rate at time t; In formula (2): The operation and maintenance costs of photovoltaic power generation, is the photovoltaic power generation power at time t, is the unit power operation and maintenance cost of wind turbine, is the fan operating power at time t, is the unit power operation and maintenance cost of the electrochemical energy storage system, is the charging power of the electrochemical energy storage system at time t, is the discharge operating power of the electrochemical energy storage system at time t, is the unit power operation and maintenance cost of the flexible direct current, is the operating power of the flexible DC at time t, is the fuel cell unit power operation and maintenance cost, is the fuel cell operating power at time t; In formula (3), Reduce costs per unit load, is the load reduction of the substation at time t, Assemble for the port substation; The load reduction model of the lower layer of the resilience enhancement strategy is as follows: (16) (17) (18) (19) (20) Where: is the importance weight of the load in the area controlled by each substation, For the substation collection in the port, Represents the node To Node The maximum power flow of the distribution line is Flow to Node , ,otherwise, ; and Represents the slave nodes The collection of nodes pointing outward and inward to the node, Represents the busbar at time t The phase angle at Representative Node To Node Reactance of distribution lines; Represents time t The total load of the node, Represents time t The node's energy storage charging power, Represents time t The node's electrical energy storage discharge power, Represents time t The charging power of the charging pile of the node, Represents time t The charging pile discharge power of the node, Represents time t The node's electrolyzer operating power, Represents time t The load shedding power of the node, Represents time t The photovoltaic output of the node, Represents time t The fan output of the node, Represents time t Flexible DC devices at the node transfer power; The electric container truck scheduling model is as follows: Taking the port plane as the object, a two-dimensional coordinate system of the port is established, and the distance between the electric container truck and the charging pile is calculated as follows: (21) Where m=1, 2, 3...n is the number of electric container trucks in the port area, k=1, 2, 3...a is the number of idle charging piles in the port area; The shortest driving distance from the electric truck to the nearby charging station in each area, , are the horizontal and vertical coordinates of the electric container trucks in each area, , is the horizontal and vertical coordinates of the location of each charging pile, is the relationship variable of the electric container truck from the pth area to the jth area. According to the driving rules of the electric container truck in the port area, the following matrix Decide: is the variable of the right boundary of the area where the charging pile and electric truck are located, satisfying formula (22) (22) After obtaining the relative position of the electric container truck and the charging pile by establishing a two-dimensional coordinate system, the working status of each charging pile is read, and the SOC of each electric container truck is read at the same time, which is recorded as (m=1,2,3,…,n), n is the total number of electric container trucks in the port area; The power required for the electric truck to travel to the charging station is calculated as shown in formula (23): (23) In the formula, It is the amount of electricity from when the electric truck receives the instruction to when it goes to the charging pile. is the shortest path distance for the electric truck to reach the nearest charging station. is the average electric energy consumed per kilometer traveled by the electric container truck, Represents the maximum battery capacity of the electric container truck. The battery power level of the electric truck when it reaches the charging station; The charging and discharging model of electric container truck is as follows: The electric trucks are charged and discharged by charging piles connected to the port power grid. The power of the electric trucks in the port is calculated as follows for each time interval: (24) (25) In the formula, and They represent the charging power flow and discharging power flow of the electric container truck respectively, and They represent the battery charging efficiency and discharging efficiency of the electric container truck respectively. It represents the total energy stored in the battery of each electric container truck at each research scheduling time node; and It is a 0-1 variable, indicating the charging and discharging status of the electric container truck; During the charging and discharging process, the state of charge cannot exceed the upper and lower limits specified by the battery. The SOC of the electric container truck can be expressed as: (26) (27) In the formula, Indicates the battery charge state of the electric container truck at the scheduling time node t; and They respectively represent the lower and upper limits of the charge state of the electric container truck during the charging and discharging process.

2. A method for improving the comprehensive energy resilience of a port considering the connection of electric container trucks to the power grid according to claim 1, characterized in that: The comprehensive energy system is modeled, including an electrochemical energy storage system model, an electrolyzer model, a hydrogen storage system model and a hydrogen fuel cell model.

3. A method for improving comprehensive energy resilience of ports considering electric container trucks connected to the power grid according to claim 2, characterized in that: The electrochemical energy storage system model is as follows: The upper and lower limits of energy storage power and the change of energy storage capacity at the beginning and end of the energy storage scheduling cycle (5) (6) In the formula, represents the charge of the electrochemical energy storage system at time t, and The corresponding electrochemical energy storage systems are The charging power and discharging power at the moment, and It is the charging efficiency and discharging efficiency of the electrochemical energy storage system; is the interval of scheduling time; is the upper limit of charging power and discharging power of the electrochemical energy storage system; variable and is a 0 / 1 variable, When it is 0, it means not charging. When it is 1, it means charging; When it is 0, it means no discharge. When it is 1, it represents discharge; (7) In the formula, is the capacity limit of the electrochemical energy storage system; Represents the amount of electricity stored in the electrochemical energy storage system at time t; It is the lowest state of charge of the electrochemical energy storage system; It is the highest state of charge of the electrochemical energy storage system.

4. A method for improving comprehensive energy resilience of ports considering electric container trucks connected to the power grid according to claim 2, characterized in that: The electrolyzer model is as follows: The electrolyzer uses electric current to decompose water to produce hydrogen and oxygen. The power supply from the power grid to the electrolyzer has the following relationship: (8) Where: is the operating power of the electrolyzer at time t, is the power input to the electrolyzer from the electric energy converted from renewable energy at time t, is the efficiency of the electrolyzer in utilizing grid electricity; Electrolyzer hydrogen production power The hydrogen production rate of the electrolyzer The relationship is as follows: (9) (10) Where: is the hydrogen production coefficient of the electrolyzer; is the Faraday efficiency; is the number of electrolyzers in the electrolyzer array, is the number of moles of electrons transferred in the hydrogen reaction; is the Faraday constant; A constant terminal voltage maintained for the AC / DC converter.

5. A method for improving comprehensive energy resilience of ports considering electric container trucks connected to the power grid according to claim 2, characterized in that: The hydrogen storage system model is as follows: The hydrogen storage system is used to store the hydrogen generated by the electrolysis of the electric energy converted from clean energy through the electrolyzer. The energy equation stored in the tank is as follows: (11) Where: is the maximum capacity of the hydrogen storage system, is the hydrogen energy state of the hydrogen storage system at time t; represents the hydrogen production rate of the electrolyzer at time t, is the hydrogen consumption rate at time t, represents the hydrogen purchase rate at time t, Indicates the hydrogen consumption rate of the hydrogen fuel cell; The charge state constraint range of hydrogen storage during operation is as shown in formula (12): (12) Where: and are the lower and upper limits of the equivalent state of charge of the hydrogen storage system, respectively; Hydrogen injection rate of hydrogen storage system With restrictions as shown in formula (13): (13) In the formula, Indicates the upper limit of the hydrogen injection rate of the hydrogen storage system.

6. A method for improving comprehensive energy resilience of ports considering electric container trucks connected to the power grid according to claim 5, characterized in that: The hydrogen fuel cell model is as follows: When a hydrogen fuel cell outputs hydrogen energy, the hydrogen energy and output power are as shown in formula (14): (14) Where: is the output power of the hydrogen fuel cell at time t; is the number of moles of electrons transferred in the hydrogen reaction; is Avogadro's constant; is the molar mass of hydrogen; is the number of electrons per coulomb; is the rated output voltage at time t; is the fuel cell conversion efficiency; During operation, the operating power of the hydrogen fuel cell needs to meet the following upper and lower limit constraints: (15) Where: and They are respectively the lower and upper limits of the output power of hydrogen fuel cells.

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