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In the process of multi-energy system optimal scheduling, due to the high data processing requirements of the multi-energy devices and loads and the complexity of the operating states of the multi-energy devices, the scheduling optimization of the system is to some extent more difficult. To address this problem, this paper proposes a regional multi-energy system optimal scheduling model based on the theory of cloud-edge collaboration. First, based on intelligent data sensors, a cloud-edge cooperative scheduling framework of the regional multi-energy system is constructed. Then, the physical model of operating state data of multi-energy system equipment and the allocation mechanism of system scheduling tasks are studied. With the cloud service application layer and the edge computing layer as the upper and lower optimization scheduling layers, the double-layer optimization scheduling model of the regional multi-energy system is established. The objectives of the model are optimal scheduling cost and minimum delay of scheduling data transmission. The multi-objective whale optimization algorithm is used to solve the model. Finally, a simulation model is built for verification. The simulation results show that the scheduling model established in this paper can effectively improve the scheduling data processing capability and improve the economy of regional multi-energy system scheduling.
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The development and operation of power grids are now focused on constructing an intelligent, informatized, and diversified new power system with new energy as the primary source, with the goal of achieving “Carbon peak and Carbon neutralization” (
In view of the development and application prospects, some scholars have begun to research the optimization methods of intelligent and informative operation and control of regional multi-energy systems. In (
However, there is a lack of detailed modeling analysis and research on the integration of edge computing technology and cloud-edge collaboration technology into the optimization modeling of regional multi-energy system operation and scheduling. There is a lack of relevant research on how to better improve the efficiency of regional multi-energy system scheduling.
Based on the above analysis, this paper studies a cloud-edge cooperative optimal scheduling model of the regional multi-energy system based on edge computing. By utilizing sensors and controllers distributed at different nodes of the regional multi-energy system for collecting and sending energy equipment data and equipment operation control, a regional multi-energy system scheduling framework is established. A multi-node cloud-edge cooperative scheduling model of the regional multi-energy system is established by coordinating different edge computing scheduling layer base stations and by allocating scheduling tasks to multiple base stations. On this basis, a double-layer scheduling optimization model of the regional multi-energy system is established for optimization, and a scheduling model solution process based on multi-objective whale optimization algorithm is given. Thus, there are three main contributions to this research. (1) A cloud-side coordinated scheduling framework of multi-node energy data information interaction for regional multi-energy systems is established in this paper. The scheduling process of the regional multi-energy system is optimized by dividing it into five service layers and configuring the corresponding computing servers in different scheduling service layers. This improves the data information processing capability of the scheduling calculation and optimization process of the system. (2) The physical model of the regional multi-energy system is established. The operating parameters of the energy supply equipment have been preliminarily clarified, and a method for sensing the operating state data of the equipment of the multi-energy system has been studied. Further, the multi-node scheduling task allocation model of the regional multi-energy systems has been established to optimize scheduling results among the systems in the coverage area of different regional edge computing layer base stations. (3) A double-layer optimization scheduling model of the regional multi-energy system is established, which aims at optimal operational scheduling costs and scheduling task transmission delays. The model is solved using the multi-objective whale optimization algorithm.
Finally, the feasibility and validity of the scheduling model established in this paper are analyzed and verified by obtaining the historical data of power grid operation in a region of Northeast China and building a simulation model.
For the regional multi-energy system, the use of a centralized optimization scheduling method may result in increased energy consumption, scheduling costs, and network latency due to the centralized transmission, processing, computation, and distribution of distributed new energy power supply operation information and load demand information. To mitigate these issues, alternative scheduling methods should be considered. Edge computing technology makes use of various data sensors, data routing and other devices configured in the regional multi-energy system to analyze and process the collected operation information data on the side of each distributed power generation equipment. The calculation results are then transmitted to the cloud service data computing center for centralized coordination and scheduling. Based on this, this paper establishes a cloud-side coordinated scheduling framework of multi-node energy data information interaction for regional multi-energy systems, as shown in
Scheduling framework of the regional multi-energy system.
The scheduling framework shown in (1) The equipment entity layer is composed of various energy equipment and equipment operation control module. The main task is to use each energy equipment to generate electricity, heat, gas and other energy supply to the consumer. Through the equipment operation control module, it controls and adjusts the operation status of energy equipment. (2) The state data perception layer is composed of various intelligent energy data collection and measurement modules. Its main task is to assist the edge computing layer and cloud service application layer in perceiving the operating state of each energy equipment in the system. (3) The edge computing layer is composed of edge computing modules and data storage. Its main task is to calculate the optimal operation scheme for each energy equipment in the regional energy system. This includes determining the optimal output of energy equipment, energy supply, and transaction prices. (4) The data network communication layer is composed of data routing, wireless modules, etc., Its main task is to facilitate the communication and transmission of energy data, scheduling data, and control commands between the state data perception layer, edge computing layer, cloud service application layer, and other layers. Its goal is to ensure quick and lossless data transmission. (5) The cloud service application layer serves as the energy management center for power generation, transmission, and supply in the regional multi-energy system. It is composed of servers and centralized scheduling centers, and its main task is to provide data storage, reading, computation, analysis, and dynamic display services for the centralized regulation and control of the regional multi-energy system. Through computation and analysis, the optimal supply scheme for a regional multi-energy system is calculated to realize the optimal scheduling of regional multi-energy system.
As shown in
Topology of the multi-energy system.
Taking doubly-fed wind turbine as an example, the physical model of the wind turbine can be described by Eq.
Therefore, there are 14 operational parameters needed to be sensed by the wind turbine, which can be expressed by Eq.
The physical model of the photovoltaic cell can be described by Eq.
Therefore, there are 10 physical parameters of the photovoltaic cell, which can be described by Eq.
The operating status of the gas turbine is mainly limited by its operating efficiency and intake volume. The physical model of the gas turbine can be described by Eq.
The physical parameters of the gas turbine can be described by Eq.
The relationship between energy input-output of a gas boiler is described by Eq.
The physical parameters of the gas boiler can be described by Eq.
The relationship between electrical energy consumption and natural gas output in the PtG equipment can be described by Eq.
The physical parameters of the gas turbine can be described by Eq.
The regional multi-energy system utilizes electricity storage batteries, gas storage equipment, and heat storage equipment for charging and discharging, which serve to regulate the output of the regional multi-energy system. Therefore, it can be described by Eqs
Assuming that the regional multi-energy system being studied includes
The edge computing layer base station provides data support and scheduling calculation services to energy consumption users and the cloud service layer. This is achieved according to the edge computing module, data storage and communication module, data routing and other equipment deployed in the system. At the same time, the base station can transmit the calculated data and collected data to the neighboring base station. Then, by allocating the computation tasks to be completed by its own base station, it realizes the cooperative computation of multiple edge computing base stations to better complete the edge node scheduling optimization in the regional multi-energy system. If the edge computing layer base station is responsible for a small amount of computation tasks, the current base station can be used to complete the scheduling tasks.
If all energy equipment and energy consumption users in the scheduling process of the regional multi-energy system perform system scheduling optimization at the same time, all the computation tasks of the edge computing layer base station are allocated according to Eq.
Meanwhile, at least one base station in the edge computing layer must perform all computational tasks while satisfying the constraint of Eq.
When performing optimized scheduling computation tasks for the regional multi-energy system, each task requires energy for computation and data communication, as well as incurs transmission delays. Therefore, the cost and transmission delay consumed by the edge computing layer and the cloud service application layer can be expressed by Eq.
In the actual optimization scheduling process, the computing process of multi-node cloud-edge cooperative scheduling in the regional multi-energy system is shown in
Multi-node cloud-edge collaborative scheduling computing process.
The state data sensing layer collects the operating state data and ledger data of each energy equipment in the equipment entity layer and stores them in the databases of the edge computing layer and the cloud service application layer. Then, the optimization scheduling task begins at each energy equipment and energy consumption user. It is then uploaded to the edge computing layer, where the computing task is allocated based on Eq.
To fully utilize the multi-node cloud-edge collaborative scheduling capability in the optimization and scheduling process of the regional multi-energy system, the double-layer optimization scheduling model of the regional multi-energy system is established as shown in
Double-layer optimization scheduling model of the regional multi-energy system.
The objective function of the upper-layer scheduling optimization model for the cloud service application layer can be described by Eq.
The objective function of the lower-layer scheduling optimization model for the edge computing layer can be described by Eq.
In addition to the consideration of system operating costs, the regional multi-energy system to perform scheduling calculations is also required to consider the scheduling task transmission delay under the multi-node cloud-edge collaborative scheduling strategy, and minimize the data transmission delay of the scheduling optimization calculation process, which can be expressed by Eq.
The supply balance constraints for electricity, gas, and heat in the regional multi-energy system can be described by Eq.
The operation constraints of multiple energy equipment in the regional multi-energy system can be described by Eq.
Data transmission constraints in the multi-node cloud-edge cooperative scheduling framework. The relevant equations can be found in Eqs
The regional grid operations flow constraints can be described by Eq.
To achieve optimal computation and control of regional multi-energy system scheduling under the framework of edge computing and cloud-edge collaborative scheduling, this paper proposes a multi-objective whale optimization algorithm, which is used to solve the optimal scheduling scheme of the regional multi-energy system.
The whale optimization algorithm is a heuristic, single-objective optimization algorithm that simulates the feeding behavior of whale groups (
In the first phase, the whale gradually approaches the prey through an encirclement approach. Assuming that the current optimal solution is the target prey, the positions of other individuals in the group are moved to the position of the optimal solution, and updated as Eq.
There are two ways to describe the feeding behavior of whales: the shrinking encirclement mechanism and the spiral updating position. a) Shrinking encirclement mechanism: It is realized by constantly encircling the prey by the value of the convergence factor b) Spiral updating position: The algorithm first calculates the distance between the current individual and the optimal solution position. Then, it approaches the optimal solution position in a spiral manner. The mathematical model can be expressed as Eq.
Both above methods have a certain probability to appear in the actual whale hunting process. Therefore, the algorithm sets the selection probability coefficient
When |
In a multi-objective optimization problem with
This paper proposes the idea of multi-objective particle swarm algorithm, which takes the global optimal solution as the target of bubble net attack, and the local optimal solution as the target of prey search. To achieve a local optimal solution, select the individual that dominates the current local optimal solution after moving positions. If the individual after moving position and the current local optimal solution do not dominate each other, randomly select both as the local optimal solution to ensure solution distribution and non-domination. The process of whale moving position fully uses the information obtained in the process of whale moving position, and the global optimal solution is selected according to the hierarchical analysis method, which ensures the effectiveness and objectivity of the global optimal solution selection process.
The distribution of the solution set of the algorithm uses the results of the crowding degree ranking in this paper as the standard for updating the solution set in the iterative process. The crowding degree is calculated using Eq.
The algorithm uses the crowding degree, which can visualize the distribution of solutions. A larger crowding degree indicates a better distribution of solutions, while a smaller crowding degree indicates a worse distribution. Therefore, during the iteration process of updating the solution set, larger solutions can be filtered based on the size of the crowding degree, and smaller solutions can be eliminated to maintain diversity and distribution of solutions.
(1) Initialize parameters, such as the output population size and iteration number, for each equipment in the regional multi-energy system. Randomly initializing the position of each individual in the output population, and initializing the local optimal value of each equipment in the regional multi-energy system. (2) Calculate the objective function value for each individual in the initial population, which represents the output power of each device in the regional multi-energy system. (3) Use the hierarchical analysis method to select the global optimal solution from the entire output population of equipment and guide the position of the equipment power output population in the desired direction. (4) To update the position of each individual of the output population of each equipment in the multi-energy system, use Eqs (5) Update the local optimal solution in the power output population of each equipment in the multi-energy system using the optimal solution domination principle of Eqs (6) Check if each individual in the equipment output population has been traversed. If not, go back to Step (4). (7) Check if the maximum number of iterations has been reached or if the algorithm iteration has met the end condition. If yes, output the optimal scheduling result of the regional multi-energy system and end the algorithm. Otherwise, go back to Step (3).
Solving algorithm.
Using the model established in this paper, the historical operation data of new energy units and the historical load data of a regional power grid in Northeast China on a typical operation day are selected. The topology shown in
The parameters of the electricity/heat/gas multi-energy system are shown in
Simulation parameters
Parameter | Value | Parameter | Value |
---|---|---|---|
Turbine efficiency of the gas turbine | 0.8 | Hydrogen storage efficiency | 0.9 |
Compressed air efficiency of the gas turbine | 1.3 | Hydrogen discharge efficiency | 0.85 |
Compressed natural gas efficiency of the gas turbine | 1.3 | Charging efficiency | 0.85 |
Hydrogen methanation efficiency | 0.75 | Discharging efficiency | 0.85 |
Gas turbine power generation costs/($/MWh) | 74.14 | Gas Storage Efficiency | 0.85 |
Gas boiler heat production costs/($/MWh) | 45.72 | Heat Storage Efficiency | 0.8 |
PtG Operating Costs/($/MWh) | 78.57 | Natural gas prices/($/m3) | 0.39 |
Photovoltaic and wind power output data.
Load data.
The regional power grid is divided into
The scheduling optimization result of the edge computing layer of the region 2 multi-energy system are given in
Electricity energy optimized scheduling results of Region 2.
Heat energy optimized scheduling results of Region 2.
Gas energy optimized scheduling results of Region 2.
According to Figures, the wind turbine and photovoltaic equipment output is consistently high throughout each time, resulting in a higher utilization of new energy in the region. Other power generation equipment is adjusted based on changes in load demand to better meet load requirements. During nighttime hours, electricity prices are low. As a result, the regional grid chooses to purchase electricity from the grid more frequently. Battery storage equipment is charged during these hours to discharge energy during times of high demand. This reduces the operation and dispatching costs of the regional multi-energy system. When demand is high, battery storage equipment will be charged and used to discharge energy when the load is high. This will reduce the operation and scheduling costs of the regional multi-energy system. To meet the heat and gas load demand in the regional multi-energy system, the edge computing layer calculates the optimal heat and gas energy supply arrangement scheme based on the acquired equipment data and load demand data. It then adjusts the operation status of the corresponding energy equipment to meet the heat and gas load demand of users in the region when the load demand is high.
Operating costs
Cost | Before Optimization | After Optimization |
---|---|---|
Equipment operating cost /$ | 236.17 | 181.93 |
Natural gas cost /$ | 146.14 | 167.10 |
Power Purchase Cost /$ | 39.81 | 21.88 |
Power sales revenue /$ | 5.50 | 28.01 |
Total cost /$ | 427.62 | 398.92 |
Optimized scheduling results of the electricity interaction.
This paper also explores the effectiveness of regional multi-energy system scheduling solution under two approaches: multi-node cloud-edge cooperative scheduling and centralized scheduling, and the results are shown in
Operating Costs Solution comparison of scheduling optimization task
Number of regions | Cloud-Edge Cooperative Scheduling Method | Centralized Scheduling Method | |||
---|---|---|---|---|---|
Number of iterations of edge computing layer | Number of iterations of cloud service application layer | Average delay/s | Average delay/s | Number of iterations | |
2 | 106 | 84 | 2.03 | 3.69 | 373 |
4 | 232 | 167 | 2.97 | 6.27 | 583 |
8 | 536 | 241 | 4.12 | 8.95 | 1386 |
16 | 1272 | 501 | 7.62 | 13.28 | 2768 |
Comparison of data information processing and calculation time before and after optimization.
When the edge computing layer has not received the latest inter-regional energy interaction commands from the cloud service application layer, the edge computing layer can perform optimization calculations of energy equipment outputs within the regional multi-energy system by directly utilizing the operating state data and ledger data of each energy equipment in the equipment entity layer collected by the state data perception layer. At the same time, the amount of energy data and equipment operation data that need to be processed is smaller when each edge computing layer performs scheduling optimization calculation compared to centralized scheduling optimization. This reduction in data results in a decrease in the number of iterative calculations required for scheduling optimization solving using the multi-objective whale optimization algorithm. The corresponding results are shown in
The results of system operation data information processing and calculation time are shown in
Based on edge computing technology and cloud-edge cooperative control framework, this paper proposes a multi-node cloud-edge cooperative optimal scheduling strategy of the regional multi-energy system coordinated with multiple edge service layer base stations. The paper establishes a two-layer optimal scheduling model for regional multi-energy systems. The method is simulated and verified through analysis, and the conclusions are presented as follows: (1) The use of the cloud edge cooperative scheduling technology for the perception, monitoring, and optimization of the regional multi-energy system can effectively improve the ability of data information processing and calculation of the multi-energy system. The time of data information processing is reduced by 20.94%, and the time of optimization calculation is reduced by 29.64%. (2) The efficiency of scheduling and optimization of the regional multi-energy system has been improved by allocating the scheduling and optimization tasks of the whole system to the edge computing service layer, and then performing cooperative computation among the multiple edge service layer base stations to reduce the amount of data computation and processing for the execution of the optimization and scheduling tasks of the regional multi-energy system; (3) Through the analysis of the scheduling optimization results of the regional multi-energy system, the double-layer optimal scheduling model of the regional multi-energy system established in this paper can increase the flexible adjustment ability of the system, and realize the economic operation of the multi-energy system.
The original contributions presented in the study are included in the article/Supplementary material, further inquiries can be directed to the corresponding author.
SL: Writing–original draft, Validation, Writing–review and editing. YT: Writing–original draft, Writing–review and editing. SC: Writing–original draft. NX: Writing–original draft. PS: Validation, Writing–original draft. KZ: Writing–review and editing. ZC: Writing–original draft, Writing–review and editing.
The author(s) declare that financial support was received for the research, authorship, and/or publication of this article. This work was supported by the National Key Research and Development Plan (No. 2017YFB0902100).
The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest.
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