A port comprehensive energy system energy dispatching method based on multi-objective optimization

Abstract

The application provides a port comprehensive energy system energy scheduling method based on multi-objective optimization, comprising: collecting and summarizing the quantity information and operation parameter information of the energy supply equipment and load equipment included in the port comprehensive energy system, and constructing a port comprehensive energy system energy management model based on the port operation characteristics; constructing a port comprehensive energy system energy supply main body topology structure, and solving the optimal energy management strategy of the port by using a completely distributed port energy scheduling algorithm; updating the dynamic weight coefficient by a certain step length based on the optimal energy management strategy, and respectively calculating the comprehensive evaluation indexes of the corresponding energy management strategies; comparing the multiple sets of comprehensive evaluation indexes, selecting the dynamic weight corresponding to the lowest comprehensive evaluation index as the optimal weight at present, and taking the energy management strategy solved based on the optimal weight as the optimal energy management strategy of the port comprehensive energy system at present.

Description

Technical Field

[0001] This invention relates to the field of port integrated energy system management technology, and more particularly to an energy dispatching method for port integrated energy systems based on multi-objective optimization. Background Technology

[0002] The shipping industry, as a key link in promoting the sustainable development of global economy and trade, accounts for more than 80% of international trade volume and more than 70% of international trade value. However, the booming development of the shipping industry has had extremely serious negative impacts on the marine environment. According to relevant surveys, the shipping industry's annual carbon emissions accounted for 3%-5% of global total emissions over the past decade. To curb the adverse effects of pollution emissions from the shipping industry and reduce emissions of sulfur and nitrogen compounds, the International Maritime Organization (IMO) spearheaded the development of the International Convention for the Prevention of Pollution from Ships (MARPOL Convention).

[0003] Current research on port energy management primarily focuses on optimizing the overall economic efficiency of the port energy system, aiming to achieve a balance between supply and demand while ensuring the safe operation of energy supply equipment. Existing studies have neglected greenhouse gas emissions from the operation of energy supply and load equipment, contradicting the clear international requirements for sustainable marine development. Furthermore, due to the complexity of the port environment, port communication bandwidth is severely limited; therefore, research on energy dispatching in integrated port energy systems should adjust real-time communication strategies among various port equipment. Summary of the Invention

[0004] The specific technical solution of this invention includes the following steps:

[0005] Collect and summarize information on the number of energy supply equipment and load equipment included in the port's integrated energy system, as well as their operating parameters. Based on the port's operating characteristics, construct an energy management model for the port's integrated energy system.

[0006] Construct the main energy supply topology of the port's integrated energy system, and use a fully distributed port energy dispatching algorithm to solve for the optimal energy management strategy for the port.

[0007] Based on the optimal energy management strategy, the dynamic weight coefficients of port economic benefits, port environmental benefits and port carbon trading are updated at a certain step size, and the comprehensive evaluation index of the corresponding energy management strategy is calculated respectively.

[0008] By comparing multiple sets of comprehensive evaluation indicators, the dynamic weight corresponding to the lowest comprehensive evaluation indicator is selected as the current optimal weight. The energy management strategy based on the optimal weight is the current optimal energy management strategy for the port's comprehensive energy system.

[0009] Furthermore, the port integrated energy system energy management model includes an objective function for port integrated energy system energy management that synergistically considers port economic benefits, environmental benefits, and carbon trading:

[0010] min{F C ,F E ,F T}

[0011] Among them, F C F represents the port's economic benefit function; E F represents the port's environmental benefit function; T This represents the port carbon trading function.

[0012] Furthermore, the three objective functions F C F E F T They are represented as follows:

[0013] F C =(C P +C H +C G )-U

[0014] F E =E P +E H +E G

[0015]

[0016] Among them, C P C H C G Represent the operating cost functions of the electricity, heat, and gas power supply equipment, respectively; U represents the operating benefit function of the port load equipment; E P E H E G Represent the sulfur and nitrogen series emissions from the operation of electric, heat, and gas-powered equipment, respectively; C Fixed Indicates the fixed operating costs of carbon capture and storage (CFS) equipment; ε Tax This indicates the price per unit of carbon dioxide emitted, i.e., the carbon tax price. This indicates the amount of carbon dioxide from electric, heat, and gas-powered equipment that has not been absorbed or captured by carbon capture and storage (CCS) devices.

[0017] Furthermore, the constraints of the energy management model for the port integrated energy system are as follows:

[0018] Port supply and demand balance constraints: Ensuring compliance with supply and demand balance constraints at all times in port energy management is specifically expressed as follows:

[0019]

[0020] in, They represent the lth i Electric, thermal, and pneumatic energy output at the node; P Ca This indicates the electrical energy consumed by carbon capture equipment to capture carbon dioxide emissions from electric, heat, and gas-powered equipment; P St This indicates the electrical energy consumed by the carbon sequestration equipment in storing carbon dioxide emitted from electrical, heat, and gas-powered equipment.

[0021] Safe operation constraints: Ensure that all energy supply equipment within the energy supply entity is within the safe operating range, specifically expressed as:

[0022]

[0023] in, These represent the minimum power output of the electric, heat, and gas power supply equipment, respectively. These represent the maximum power output of the electric, heat, and gas power supply equipment, respectively.

[0024] Furthermore, when solving for the optimal energy management strategy for the port: a comprehensive evaluation index is constructed based on dynamic weight coefficients, and the objective function of the port's integrated energy system energy management is reconstructed as follows:

[0025] min{a·F C +b·F E +c·F T}

[0026] Where a, b, and c represent the port's economic benefits F, respectively. C Port environmental benefits F E and port carbon trading F T The dynamic weight coefficients;

[0027] Among them, the port economic benefits F C Port environmental benefits F E and port carbon trading F T The dynamic weight coefficients satisfy a+b+c=1.

[0028] Based on the reconstructed port energy management objective function and an event-triggered mechanism, the communication strategy triggering conditions among energy supply entities within the port integrated energy system are expressed as follows:

[0029]

[0030] in, As an auxiliary variable, For the l i Measurement error at the node;

[0031] Based on the event-triggered mechanism, when the triggering condition is met, the marginal cost at that time is reported and broadcast to each energy entity, and the control protocol of the energy supply equipment is updated, as shown below:

[0032]

[0033] in, and They represent the lth i Node and l j The marginal cost of the node at the time of its most recent trigger;

[0034] When the triggering conditions are not met, the marginal cost of each energy entity will be based on the value at the time of the previous event trigger.

[0035] This invention provides an energy dispatching method for integrated port energy systems based on multi-objective optimization. Targeting an electricity-heat-gas coupled integrated port energy system, this invention constructs a multi-objective integrated port energy management model that synergistically considers port economic benefits, environmental benefits, and carbon trading. In addition to incorporating renewable energy supply equipment, this model integrates carbon capture and storage technologies, focusing on port carbon dioxide emissions to reduce greenhouse gas emissions. Furthermore, this invention provides a fully distributed port energy optimization dispatching method based on an event-triggered mechanism for integrated port energy systems. Attached Figure Description

[0036] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0037] Figure 1 For the structural framework of the port's integrated energy system;

[0038] Figure 2 Test the physical and communication topology of the port's integrated energy system;

[0039] Figure 3 The power output trajectory and incremental cost of the port's integrated energy system were tested to measure the power network output of the system.

[0040] Figure 4 The power and incremental cost output trajectory of the thermal network of the port integrated energy system were tested.

[0041] Figure 5 The power output trajectory and incremental cost of the gas energy network of the port integrated energy system were tested.

[0042] Figure 6 Output trajectories for event triggering at certain nodes of the port integrated energy system test system;

[0043] Figure 7 To test the power output of each node in the port integrated energy system under different scenarios;

[0044] Figure 8 Scoring of various aspects of the port integrated energy system test system under different weighting coefficients;

[0045] Figure 9 The numerical trajectory of the comprehensive score of the port integrated energy system test system under different weighting coefficients. Detailed Implementation

[0046] To enable those skilled in the art to better understand the present invention, the technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention. 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 skilled in the art without creative effort should fall within the scope of protection of the present invention.

[0047] It should be noted that the terms "first," "second," etc., in the specification, claims, and accompanying drawings of this invention are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such data can be interchanged where appropriate so that the embodiments of the invention described herein can be implemented in orders other than those illustrated or described herein. Furthermore, the terms "comprising" and "having," and any variations thereof, are intended to cover a non-exclusive inclusion; for example, a process, method, system, product, or apparatus that comprises a series of steps or units is not necessarily limited to those steps or units explicitly listed, but may include other steps or units not explicitly listed or inherent to such processes, methods, products, or apparatus.

[0048] The overall structure of the port integrated energy system described in this invention is shown in the attached figure. Figure 1 As shown, the system includes an electrical network, a thermal network, and a gas network, and can be divided into m energy entities according to the port's operational nature. Each energy entity has both energy supply and consumption characteristics. The energy supply equipment in the port's integrated energy system includes primary energy supply equipment, such as internal combustion engine units, gas turbine units, and energy storage equipment; renewable energy equipment, such as wind turbine units and photovoltaic units; electrical and thermal energy storage equipment; mechanical drive and daily life load equipment; carbon capture and carbon sequestration equipment; combined heat and power (CHP) equipment and P2G equipment for electrothermal and electrical conversion; and several transmission lines.

[0049] The port integrated energy system can be divided into four parts according to the port's operational characteristics: heterogeneous energy supply and load center, heterogeneous energy conversion center, data processing center, and heterogeneous energy management center. The heterogeneous energy supply and load center includes traditional primary energy supply equipment, renewable energy equipment, energy storage equipment, and load equipment. The data processing center collects data in real time, including real-time data collection of heterogeneous energy supply output, real-time data collection of load equipment energy consumption, and real-time data collection of energy storage equipment energy storage. The calculations on the data include the calculation of the total output and total energy consumption of the heterogeneous energy supply and load center, the calculation of dynamic weighting coefficients, the calculation of optimal energy dispatch strategies, the calculation of economic benefit objective functions, the calculation of environmental benefit objective functions, and the calculation of total carbon trading volume.

[0050] This embodiment uses a 33-node system as an example, which is divided into 6 energy entities. Their physical structure and communication topology are shown in the attached figure. Figure 2 As shown. The power network, thermal network, and gas network have 12, 11, and 10 nodes respectively. This invention provides an energy dispatching method for a port integrated energy system based on multi-objective optimization, the technical solution of which includes the following steps:

[0051] Step 1: Collect and summarize information on the number and operating parameters of energy supply and load equipment in the port's integrated energy system, and construct an energy management model for the port's integrated energy system based on the port's operating characteristics.

[0052] Furthermore, the energy management model for the integrated port energy system constructed in step 1 includes:

[0053] Step 1.1: The energy management objective function of the port integrated energy system, which synergistically considers the port's economic benefits, environmental benefits, and carbon trading, can be expressed as:

[0054] min{F C ,F E ,F T}

[0055] Among them, F C F represents the port's economic benefit function; E F represents the port's environmental benefit function; T Let F represent the port carbon trading function. Further, the three objective functions F... C F E F T They can be represented as:

[0056] F C =(C P +C H +C G )-U

[0057] F E =EP +E H +E G

[0058]

[0059] Among them, C P C H C G Represent the operating cost functions of the electricity, heat, and gas power supply equipment, respectively; U represents the operating benefit function of the port load equipment; E P E H E G Represent the sulfur and nitrogen series emissions from the operation of electric, heat, and gas-powered equipment, respectively; C Fixed Indicates the fixed operating costs of carbon capture and storage (CFS) equipment; ε Tax This indicates the price per unit of carbon dioxide emitted, i.e., the carbon tax price. This indicates the amount of carbon dioxide emitted by electric, heat, and gas-powered energy supply equipment that is not absorbed or captured by carbon capture and storage (CCS) equipment.

[0060] Furthermore, the numerical values ​​for each model in step 1.1 are as follows:

[0061] (1)F E The greenhouse gas emissions from the port's internal electrical, thermal, and gas energy networks, representing the port's environmental benefit function, can be expressed as follows:

[0062] E P =0.649*p 2 -2.7*p+2*e 0.03*p +0.041

[0063] E H = (0.00050 + 0.0080) * h

[0064] E G = (0.00055 + 0.0074) * g

[0065] Among them, E P E H E G p, h, and g in the equation represent the sum of the output power of the corresponding energy network power supply equipment.

[0066] (2) It can be represented as:

[0067]

[0068]

[0069]

[0070] Among them, the capture efficiency of carbon capture equipment All are 0.85; CO2 emission coefficients per unit of electrical energy, heat energy, and gas energy consumed. Both are 0.7.

[0071] Furthermore, the operating cost models for each energy supply device, energy storage device, and energy conversion device in step 1.1, the operating benefit model for load devices, and the operating cost model for carbon resupply and carbon sequestration devices are shown below:

[0072] Fuel-fired power supply equipment: C FP =0.35*p 2 +2.85*p+32

[0073] Oil-fired heating equipment: C FH =0.12*h 2 +4.55*p+100

[0074] Cogeneration equipment: C CHP =0.0345*p 2 +12.5*p+0.03*h 2 +4.2*h+0.031*p*h+230

[0075] P2G equipment: C P2G =0.05*75*p

[0076] Renewable power supply equipment: C RP =0.12*p+310*e [-1.2*(120-p) / (120-90)]

[0077] Renewable heating equipment: C RH =0.065*p+350*e [-1.2*(150-p) / (150-50)]

[0078] Energy storage devices: C PS =0.43*(p+0.08) 2 +0.085*|p|

[0079] Thermal storage equipment: C HS =0.44*(h+0.09) 2 +0.085*|h|

[0080] Gas-fired power supply equipment: C GP =1.5*10 -6 *g 3 +0.006*g 2 +50g+5

[0081] Load equipment (electric): U EL-P =0.4*p 2 +40.6*p+75

[0082] Load equipment (heat): U EL-H =0.4*p 2 +50.3*p+40

[0083] Load equipment (gas): U EL-G =0.5*p 2 +20.6*p+60

[0084] Step 1.2: Physical constraints to ensure safe port operation, including:

[0085] (1) Port supply and demand balance constraint: In order to ensure the daily operation of the port, it is necessary to ensure that the supply and demand balance constraint is always observed in port energy management, which can be specifically expressed as:

[0086]

[0087] in, They represent the lth i Electric, thermal, and pneumatic energy output at the node; P Ca This indicates the electrical energy consumed by carbon capture equipment to capture carbon dioxide emissions from electric, heat, and gas-powered equipment; P St This indicates the electrical energy consumed by carbon sequestration equipment to store carbon dioxide emitted from electrical, heat, and gas-powered equipment.

[0088] (2) Safety Operation Constraints: To ensure the safe and reliable operation of the port, it is necessary to ensure that all power supply equipment within the power supply entity is within the safe operating range, which can be specifically expressed as:

[0089]

[0090] in, These represent the minimum power output of the electric, heat, and gas power supply equipment, respectively. These represent the maximum energy output of the electric, heat, and gas power supply equipment, respectively. In this embodiment, the operating cost models for each power supply device, energy storage device, and energy conversion device, the operating benefit model for the load equipment, and the output constraints for carbon replenishment and carbon sequestration equipment are as follows:

[0091] 50≤P≤220, 50≤h≤220, 100≤g≤1000

[0092] Step 1.3: Based on the port's operational characteristics, the port's integrated energy system is divided into multiple energy entities. Therefore, the objective function is modeled using these energy entities as the smallest unit. At this point, the port integrated energy system energy management objective function in Step 1.1 can be rewritten as:

[0093]

[0094]

[0095]

[0096] Among them, l i This represents the i-th node in the l-th energy entity of the port integrated energy system; all other characters represent the l-th node. i The corresponding physical quantities of the nodes.

[0097] Step 2: Based on the equipment information collected and summarized in Step 1, construct the main topology of the port's integrated energy system, and use a fully distributed port energy dispatching algorithm to solve for the optimal energy management strategy for the port.

[0098] Furthermore, the fully distributed port energy scheduling algorithm used in step 2 includes:

[0099] Step 2.1: Construct a comprehensive evaluation index based on dynamic weight coefficients, and reconstruct the energy management objective function of the port integrated energy system as follows:

[0100] min{a·F C +b·F E +c·F T}

[0101] Where a, b, and c represent the port's economic benefits F, respectively. C Port environmental benefits F E and port carbon trading F T The weighting coefficients.

[0102] Furthermore, the dynamic weight coefficients of each objective function in step 2.1 satisfy a+b+c=1.

[0103] Step 2.2: Based on the port energy management objective function reconstructed in Step 2.1, and using an event-triggered mechanism as a foundation, the communication strategy triggering conditions between energy supply entities within the port integrated energy system can be expressed as follows:

[0104]

[0105] in, It is an auxiliary variable. For the l i Measurement error at the node.

[0106] Step 2.3: Based on the event triggering mechanism in Step 2.2, when the triggering condition is met, the marginal cost at this time is reported and broadcast to each energy entity, and the control protocol of the energy supply equipment is updated. This can be represented as:

[0107]

[0108] in, and They represent the lth i Node and l j The marginal cost at the moment the node was most recently triggered.

[0109] When the triggering conditions are not met, the marginal cost of each energy entity will be based on the value at the time of the previous event trigger.

[0110] Furthermore, attached Figure 3 Appendix Figure 4 and attached Figure 5 The output trajectories of power and incremental cost for the electric power network, thermal power network, and gas power network are shown respectively when the dynamic weighting coefficients are [0.40, 0.20, 0.40]. (See attached image.) Figure 6 Record the event trigger times for nodes 1.3, 1.5, 1.6, 4.4, 5.3, 5.5, and 6.1. According to the appendix... Figure 3 -Appendix Figure 6 This invention can verify the effectiveness of the energy scheduling method for port integrated energy systems based on multi-objective optimization proposed in this invention, and fully demonstrate that the invention can effectively address the limitation of port communication bandwidth.

[0111] Step 3: Based on the optimal energy management strategy provided in Step 2, update the dynamic weight coefficients with a step size of 0.05, and calculate the comprehensive evaluation index of the corresponding energy management strategy. The dynamic weight coefficients can be specifically divided into 11 groups according to the step size: [0,1,0], [0.05,0.90,0.05], [0.10,0.80,0.10], [0.15,0.70,0.15], [0.20,0.60,0.20], [0.25,0.50,0.25], [0.30,0.40,0.30], [0.35,0.30,0.30], [0.40,0.20,0.40], [0.45,0.10,0.45], and [0.50,0,0.50].

[0112] Step 4: Based on the dynamic weighting coefficients, a comprehensive evaluation index is constructed. Using the 11 sets of dynamic weighting coefficients set in Step 3, the energy management strategy and its corresponding evaluation index are obtained. (Appendix) Figure 7 This study aims to test the power output of each node in the energy management problem of a port integrated energy system under different scenarios. (Attached) Figure 8 This provides the numerical values ​​for the economic benefits, environmental benefits, and carbon trading objective functions corresponding to the 11 sets of dynamic weight coefficients. (Appendix) Figure 9This is a trajectory graph showing the specific values ​​of the multi-objective energy management comprehensive evaluation index of the test port integrated energy system under 11 sets of dynamic weight coefficients. According to the above analysis, the energy management scheme corresponding to the lowest score, which is the optimal energy management strategy, occurs at the time when the dynamic weight coefficient is [0.45, 0.10, 0.45]. The energy management strategy obtained at this time is the optimal energy management strategy for the port integrated energy system at that moment.

[0113] Step 5: The Heterogeneous Energy Management Center sends the optimal energy management strategy to each energy entity to complete the port energy dispatch for the current stage.

[0114] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. An energy dispatching method for a port integrated energy system based on multi-objective optimization, characterized in that, include: Collect and summarize information on the number of energy supply equipment and load equipment included in the port's integrated energy system, as well as their operating parameters. Based on the port's operating characteristics, construct an energy management model for the port's integrated energy system. Construct the main energy supply topology of the port's integrated energy system, and use a fully distributed port energy dispatching algorithm to solve for the optimal energy management strategy for the port. Based on the optimal energy management strategy, the dynamic weight coefficients of port economic benefits, port environmental benefits and port carbon trading are updated at a certain step size, and the comprehensive evaluation index of the corresponding energy management strategy is calculated respectively. By comparing multiple sets of comprehensive evaluation indicators, the dynamic weight corresponding to the lowest comprehensive evaluation indicator is selected as the current optimal weight. The energy management strategy based on the optimal weight is the current optimal energy management strategy for the port's comprehensive energy system. When solving for the optimal energy management strategy for a port: a comprehensive evaluation index is constructed based on dynamic weight coefficients, and the objective function for energy management of the port's integrated energy system is reconstructed as follows: in, respectively port economic benefits Port environmental benefits and port carbon trading The dynamic weight coefficients; Among them, port economic benefits Port environmental benefits and port carbon trading The dynamic weight coefficients satisfy , Based on the reconstructed port energy management objective function and an event-triggered mechanism, the communication strategy triggering conditions among energy supply entities within the port integrated energy system are expressed as follows: in, As an auxiliary variable, For the first Measurement error at the node; Based on the event-triggered mechanism, when the triggering condition is met, the marginal cost at that time is reported and broadcast to each energy entity, and the control protocol of the energy supply equipment is updated, as shown below: in, and They represent the first Node and the The marginal cost of the node at the time of its most recent trigger; When the triggering conditions are not met, the marginal cost of each energy entity will be based on the value at the time of the previous event trigger.

2. The energy dispatching method for a port integrated energy system based on multi-objective optimization according to claim 1, characterized in that: The port integrated energy system energy management model includes an objective function for port integrated energy system energy management that synergistically considers port economic benefits, environmental benefits, and carbon trading: in, This represents the port's economic benefit function; Represents the port's environmental benefits function; This represents the port carbon trading function.

3. The energy dispatching method for a port integrated energy system based on multi-objective optimization according to claim 2, characterized in that: Three objective functions , , They are represented as follows: in, Let each represent a function representing the operating cost of electrical, thermal, and gas power supply equipment. This represents the port load equipment operation benefit function; These represent the sulfur and nitrogen compounds emitted by electric, heat, and gas-powered equipment, respectively. This indicates the fixed operating costs of carbon capture and storage (CCS) equipment; This indicates the price per unit of carbon dioxide emitted, i.e., the carbon tax price. This indicates the amount of carbon dioxide from electric, heat, and gas-powered equipment that has not been absorbed or captured by carbon capture and storage (CCS) devices.

4. The energy dispatching method for a port integrated energy system based on multi-objective optimization according to claim 2, characterized in that: The constraints of the energy management model for the port integrated energy system are as follows: Port supply and demand balance constraints: Ensuring compliance with supply and demand balance constraints at all times in port energy management is specifically expressed as follows: in, They represent the first The electrical, thermal, and pneumatic energy output at the nodes; This refers to the electrical energy consumed by carbon capture equipment in capturing carbon dioxide emissions from electric, heat, and gas-powered equipment. This indicates the electrical energy consumed by the carbon sequestration equipment in storing carbon dioxide emitted from electrical, heat, and gas-powered equipment. Safe operation constraints: Ensure that all energy supply equipment within the energy supply entity is within the safe operating range, specifically expressed as: in, These represent the minimum power output of the electric, heat, and gas power supply equipment, respectively. These represent the maximum power output of the electric, heat, and gas power supply equipment, respectively.

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