Model design and structure research for integration system of energy, information and transportation networks based on ANP-fuzzy comprehensive evaluation

1 Introduction

Establishing global energy Internet to meet global power demands in clean and green manner is an effective way to solve the problem of world energy crisis, environmental pollution and climate change. The integration and development of global energy, information and traffic is based on the successful practice of China UHV power grid and global energy Internet, and puts forward the theoretical innovation to promote the development of global economic transformation. The integration of energy, information and transportation networks plays a major practical role in advancing global economic transformation, promoting innovative development of green energy, Internet economy and intelligent transportation, and stimulating new market demand and new economic patterns. Meanwhile, it will also be a new engine for global economic growth. Currently, the interconnection of information network and transportation network, “nervous system” and “limbs system” of social life respectively, is basically accessible to main countries and major cities worldwide and is gradually extending to rural and remote areas. The energy network is considered as the “vascular system” of social production activity, but the energy interconnections among countries and continents are obviously in a hysteretic and discontinuous state. A globally interconnected energy network platform is not established,so great efforts remain to be made in theoretical research and engineering practice of global energy interconnection.Besides, as an innovative idea, the integration of energy,information and transportation networks fails to effectively guide the practice of integration of energy, information and transportation networks in technology due to few deep researches on system model, system structure and top-level design of three-network integrated system.

At present, there are few researches on integration of the three networks, but as a cross-industry, crossdomain, and multi-form integration concept, the threenetwork integration well matches the idea of smart city.However, there are a large number of technical researches on smart city, some parts of which provide references for technical realization and structural setup of threenetwork integration. Reference [1] depicts the development vision and great value of three-network integration and specifies the major task of accelerating to build global energy interconnection and promote three-network integrated development, providing a new solution to boost sustainable development of the world economy; but there is no discussion on realization of three-network integration technology. Reference [2] makes big data statistics and analysis on relation between traffic distribution and seasonal temperature of Santander City, Spain (a test site) by means of KNIME open source platform and Poisson distribution model to predict the follow-up traffic distribution of cities and provide decision basis for urban traffic management, which has some reference value for fusion analysis of information flow and transportation flow. Reference [3] discusses the network system structure based on small cell (generally referring to flexibly arranged low-power wireless access points in small coverage) in respect of information communication application of smart city, providing a reference for information flow system construction. In Reference [4], a context-aware civic service smart city framework based on cloud architecture is put forward and the contents of data, service, safety and organization that should be included in the framework have been discussed through common scenes of smart city.Reference [5] takes Seoul and San Francisco as examples.From the perspective of city construction, development and design, this reference illustrates that the efficient and sustainable development structure of smart city should include 8 key factors such as data openness and advanced intelligent technology support by classified researches on 6 dimensions like city openness and service innovation as well as 17 quantitative and qualitative sub-dimensions. This reference can be consulted for structure design of threenetwork integration. Reference [6] puts forwards an outline structure of smart city based on big data analysis of cloud,which divides city data into three layers, including layer of data acquisition, analysis and filtering, layer of source data mapping and connection, and layer of interactive browsing.The structure is verified by the public data of Bristol. In Reference [7], a context-aware civic service smart city framework based on cloud architecture is put forward and the contents of data, service, safety and organization that should be included in the framework have been discussed through common scenes of smart city. Reference [8] holds that the government should be designated as the organizer who provides funds and retain qualified personnel to promote multi-disciplinary coordination and cooperation,and establish technical standards and legal norms in terms of government functional orientation against the context of smart city. Reference [9-10] has analyzed the activity of the Chinese vehicles in 2016 from the angle of the traffic trips,and has been able to use the clustering model of traffic trips’ intensity to divide the city’s function zoning. The reference has a certain significance for the point distribution design of energy, and traffic diverting by using information technology. The references above can be consulted for the design of system structure and hierarchical structure of three-network integration.

The paper puts forward a system model and technical structure of three-network (energy, information and transportation networks) integration on the basis of the new idea, strategy and engine of integrated development and in light of their own characteristics and relevant results of smart city researches. It provides technical references for practical implementation of integration of the three networks.

2 Three-network Integrated System Model

The integration of the interdependent energy,information and transportation networks is an innovative mode. The energy dispatching requires information support, and the energy storage dispatching requires transportation support, such as the battery circulation among battery charging & swapping stations. The information delivery and transportation also require energy support. The deeply integration of energy flow, information flow and transportation flow using 5G communication,ultra-high voltage and IOT technologies can fully realize the characteristics and efficiency of energy, information and transportation and provide economic and social development. Therefore, as shown in Fig. 1, with dispatching of energy flow and information flow as a focus,clean energy of wind power and solar power as carrier,battery charging & swapping station as medium and all kinds of transportation flows considered as entity in this paper, a five-in-one three-network integrated system model is proposed by full use of technologies of IOV and IOT.

2.1 Dispatching Center

Dispatching center, mainly composed of energy dispatching and information dispatching, is the central system of three-network integration. The former mainly includes dispatching of clean energy to realize balanced dispatching of energy flow in power generation and load.The latter mainly includes delivery of information to support information interaction. The energy dispatching and information dispatching complement each other. The latter provides dispatching basis for operation of energy flow and the former supplies energy complement for live transmission of information flow.

2.2 Energy Supply System

Energy supply system consists of clean energy such as wind power, solar power, hydropower and biomass power.

The mismatches between the power generation and the load are balanced by the large-scale energy storage station. If sufficient clean energy is supplied, the energy can be stored; if there is insufficient clean energy and large load, the system shall be supplemented energy.Through ultra-high voltage transmission line or other power transmission mode, the clean energy is transmitted to all load zones by uniform dispatching of energy dispatching center.

Fig. 1 Design of System Model of Three-network Integration

2.3 Battery Charging & Swapping System

Battery charging and swapping system, consisting of battery charging & swapping stations and charging piles at all places, is the medium for integration of energy and transportation. The swapping battery pack of the system can serve as energy storage system, a make-up system for energy balance. Through intelligent distribution network, the battery charging & swapping system, which is connected to the energy supply side through dispatching of energy dispatching center, realizes energy storage or supplement and provides clean energy for information flows of electric vehicles, shore power along the port and rail transportation by battery charging and swapping.Meanwhile, under the condition of uniform battery interface and specification, battery dispatching among battery charging & swapping stations can be realized through information processing technology such as transportation flow analysis and prediction. The station with sufficient battery energy storage can be dispatched to the station with much swapping of battery to make full use of energy and guarantee smooth transportation flow.

2.4 Transportation Flow System

Transportation flow system consists of electric vehicles,port ships, metro & bullet train, and auxiliary power unit(APU) replacement equipment of airport. It is mainly characterized by utilization of clean energy. In regional transportation system, the energy supply is achieved through regional battery charging & swapping stations.The electric vehicles, port ships and other traffic vehicles constitute a regional IOV system through IOV technology,deeply integrating the transportation flow, energy flow and information flow.

2.5 IOT System

Regional IOV systems are linked through information flow and the mobile equipment, security and protection monitoring equipment and other sensors to form a whole IOT system. The energy flow and information flow of the whole system can be better dispatched to meet the energy and information demands for system operating through real-time interaction between IOV system or IOT system and energy dispatching center & information dispatching center to form a five-in-one closed-loop system of threenetwork integration.

In order to further research and verify the rationality of the system, we use analytic network process (ANP) method and fuzzy comprehensive evaluation method to evaluate the system structure.

The basic model of ANP is as follows:

In ANP, the control layer element set is {B1, B2, …,Bm},the network layer element set is {C1, C2, …, Cn}, where the Cj has the element ejk(k = 1,2, ..., NJ). The elements in the element set of Cj are analyzed according to their influence on ejk, the judgement matrix is constructed under control criteria. Then the sorting vectoris obtained by the feature root method. If the abovementioned eigenvectors pass the consistency test, then they are written in the form of a matrix, which gives a local weight vector matrix:

If elements in Cj are not affected by elements in Ci,wij=0. By comparing the internal and external relationships among the elements of the other element set,

that Ws are composed of sorting vectors of each element interacting with each other in the network layer.

Under the control layer BS criterion, the importance of the network layer elements to Cj(J = 1, ..., N) is compared to obtain a normalized sorting vector Hj

Then we can create a weighted matrix H

Multiply matrix H with W, we can get a weighted super matrix To get steady, calculate the relative ordering vector of each super matrix.

The prerequisite, which the value of the original matrix corresponding to the stable weight of each evaluation index,is limit convergence and unique. Through the calculation,we can get the weight of each index.

The basic model of the Fuzzy Comprehensive Evaluation is as follows:

Set the judging object to P: its factor set U = {u1,u2,u3… um}, Assessment Set V={v1,v2,…,vm}. The evaluation matrix is obtained by making a fuzzy evaluation of each factor in U according to the grade index of the Assessment Set:

Among them, rij indicates UI about the degree of VJ affiliation.

C can be selected appropriately, making 0 ≤ rij ≤ 1 ,so that (U, V, R) constitutes a fuzzy comprehensive evaluation model. After determining the index of importance of each factor (also known as weight), record A={a1, a2, ..., an} and,

then it is synthesized and normalized, B = {b1, b2, ..., bm},so we can determine the level of P.

Here we select the factor set U = {relevance, feasibility,compatibility, technical maturity}; V = {strong, little strong, medium, weak}; Weight A = (0.2, 0.25, 0.3, 0.25)from ANP method.

The calculation shows that the structure of system is little strong, so the design is reasonable.

To effectively support and promote the practice of the system model, the system structure of three-network integration is researched and designed as follow based on the above mentioned five-in-one closed-loop system model for three-network integration.

3 Research on System Structure of Threenetwork Integration

The three-network integration is a multi-industry, crossdomain and multi-disciplinary complex giant system. The complicated system covers energy, transportation and information industries. In terms of technical aspects, it involves hardware, software and data processing. And from the professional aspects, it involves ultra-high voltage,smart grid, clean energy, energy storage, transportation,computer, sensors and information communication. In essence, the three-network integrated system is a service carrier on the basis of technical development, which caters and promotes social and economic development. Therefore,with a view to the service essence of social and economic development of the three-network integration and logic structure of technical realization, this paper constructs a system structure of the three-network integration consisting of fundamental guarantee layer, transmission support layer,storage and transfer layer and application service layer, as is shown in Fig. 2.

Fig. 2 System Structure of Three-network Integration

3.1 Fundamental Guarantee Layer

The fundamental guarantee layer is the underlying support layer of the three-network integrated system,consisting of clean energy guarantee, information communication guarantee and transportation guarantee.Clean energy guarantee refers to energy supply guarantee by wind power generation, hydropower generation, solar power generation and biomass power generation and other clean energy. Information communication guarantee refers to effective information collection guarantee through various sensors, microwave, satellite, camera, RFID label and other equipment. Transportation guarantee refers to guaranteeing efficient operation of transportation through air-sea-land transportation means such as auto, port, and airport.

3.2 Transmission Support Layer

The transmission support layer is a middle passage connecting the fundamental guarantee layer and the storage and transfer layer. It mainly guarantees stable, safe and efficient transmission of information flow and energy flow among various media. The energy flow transmission is guaranteed mainly through ultra-high voltage, smart grid,submarine cable, superconducting transmission and various transformer, substation and power distribution equipment.The information flow is safely transmitted through 5G communication in Fig. 3, optical fiber communication,Internet, IOT and wireless communication. The energy flow and information flow integrate and support each other.

3.3 Storage and Transfer Layer

The storage and transfer layer, is the middle layer which achieve energy dispatching balance and data storage & processing. It is also an important link to guarantee smooth service application of the threenetwork integration. The layer mainly includes energy storage and information storage. The energy is mainly stored through electromagnetic energy storage, pumped storage, electrochemical energy storage, physical energy storage and compressed-air energy storage. The clean electric energy can also be supplied through dispatching.The information storage means that various information retrieval and analysis services are provided through storage of basic database, business database and service database and analysis and processing of various big data.

3.4 Application Service Layer

The application service layer specifically embodies the integration of the three networks. It mainly provides various practical applications of the three-network integration, including electric vehicle application, electric boat, electric aircraft, electric railway and unmanned vehicle. Meanwhile, along with the development of the three-network integration, it can expand and promote the development of smart transportation, smart energy,smart part, smart city, shore power along port and other Internet integration projects as well as the electric power replacement development.

4 Conclusion

Fig. 3 5G systems

Energy, information and transportation, as three pillar industries of entity economy, play a core and leading role in economic development. The three-network integrated development is an important item of global infrastructure interconnection and economic globalization, the objective requirement of social productivity development and necessary result of technical progress. It is of great significance to promote global economic transformation and sustainable development. The development planning and top-level design of the three-network integration provides important theoretical and technical guidance for deepening research on major strategic issues in fields of world energy, information and transportation and establishing the working mechanism of joint participation in research by government, relevant industrial enterprises and organizations. The system model and technical structure of three-network integration put forward in the paper promotes the implementation, development and actual fusion of three-network integration, drives the innovative idea of three-network integration to be applied in actual conditions and provides a reference for research institutions and personnel.

Acknowledgements

This work was supported by National Key Research and Development Program of China (2017YFB0903000).