Microgrid In China Research Articles

Bio-inspired distributed load frequency control in Islanded Microgrids: A multi-agent deep reinforcement learning approach

To prevent errors in load frequency control (LFC) decision-making in an islanded microgrid and reduce the waste of frequency regulation resources, a fully distributed “starfish” load frequency control method is proposed. For this method, a novel deep reinforcement learning algorithm called the distributed decomposed multirole multiagent deep deterministic policy gradient (DDMR-MADDPG) algorithm is introduced. This algorithm treats each unit as an agent, enabling centralized training of all the agents. Through the coordination and control of multiple agents, a global optimal strategy can be obtained. During online application, the algorithm employs a distributed implementation strategy, enabling each unit to make decisions autonomously. This decision-making strategy is akin to the distributed neural network of a starfish, and it can fundamentally improve the efficiency and correctness of decision-making. In addition, it employs multiple techniques, including value function decomposition, multirole learning, imitation learning, and curriculum learning approaches. The performance of the proposed method compared with 24 existing methods is demonstrated on a simulated LFC model of the Zhuzhou Island microgrid in China.

Multiple criteria analysis for electrifying off-grid island using renewable energy microgrid or submarine cable

Renewable energy microgrids are a new option for powering remote islands. To explore the feasibility of constructing island microgrid in China, based on the failed Dongfushan Island Demonstration Microgrid Project caused by equipment failure, low economic benefits, low residents' satisfaction, and poor power supply stability, this paper compares two power supply methods, microgrid and submarine cable. A systematic multiple criteria analysis method is established to compare these two methods, including economic analysis, risk assessment, energy spilled and energy shortage. Net present value and the life-cycle cost method are used to establish the economic cost model. Fuzzy analytic hierarchy process is used to establish the risk assessment model. Additionally, the simulation using PVsyst software is used to calculate the energy spilled and energy shortage. Furthermore, future trends are predicted with data to provide suggestions for decision-makers. Multiple criteria analysis results showed that energy spilled and shortages are inevitable for the use of microgrid on seasonally tourist islands like Dongfushan Island, with energy spilled and shortages rate as high as 50.11% and 37.57% in the worst case. The microgrid risk level is relatively low risk, higher than the lowest risk level for submarine cables. At full capacity, the cost of microgrid (34.03 million yuan) is comparable to submarine cables (30.31 million yuan), making the latter more suitable for power supply due to its better reliability.

Operational Strategy and User Price Preference Analysis of China’s Microgrids: Based on An Evolutionary Game Model

As an effective supplement to the power grid, microgrid systems can make full use of renewable energy and solve the problem of grid connection and absorption of renewable energy. However, microgrid faces the challenges of benefit fluctuation caused by fixed pricing mode with unstable renewable energy supply and changing user’s demand. A well-designed pricing mode is necessary while yet to be fully discussed. To solve this problem, this paper introduces flexible operational strategies and pricing mechanism due to the regional differences in resource endowment, microgrid technology mix, user demand and electricity price of external grid. The evolutionary game method is used to explore the operational strategy and pricing mechanism applicable to microgrids with different characteristics and users with different demands, so as to provide valuable reference for pricing standardization of microgrids in China. Based on the theoretical model, we deduce the equilibrium strategy of microgrid facing stable users and flexible users, and discusses the operational strategy and pricing mechanism of microgrid facing different user demands by using numerical simulation method. The results indicate that: (1) Considering the technical characteristics and economic performance, most of the microgrids tend to be connected to the grid and use real-time pricing mode. (2) The initial price between the microgrid and the user, the proportion of independent power generation when the microgrid is connected to the grid, and the tariff of the external grid are the key factors affecting the equilibrium point of the game between the microgrid and the users.

A Critical-analysis on the Development of Micro Grid in China

With the combination of Internet, information technology and energy, micro grid plays an important role in the adjustment of energy structure with its abundant resources and friendly environmental benefits. This paper introduces the status of micro grid and renewable Energy of the status quo, In the second part, the development status of the micro-grid is introduced in the second part. In the third part, the future development trend of micro-grid is given. The conclusion of this paper and the suggestion of micro-grid development are given.

A single-leader and multiple-follower stackelberg model for the look-ahead dispatch of plug-in electric buses in multiple microgrids

Plug-in electric buses have great potential to enhance the profits of operators in multiple-microgrid systems via the use of vehicle-to-grid technology. In contrast to stationary energy storage units, a plug-in electric bus can move among different microgrids to provide not only passenger transportation service but also energy transportation service. In this paper, a single-leader and multiple-follower model based on the Stackelberg game method is proposed for the look-ahead dispatch of bus routes and power allocation in microgrids. First, a time-space trip model for a fleet of plug-in electric buses was established, and the total costs of the plug-in electric bus operator were optimized as a leader-level problem. Then a rolling energy management strategy was formulated as a follower-level problem to optimize the total costs of each microgrid operator and to deal with the prediction error of the distributed energy resources and loads. Next, the proposed bi-level optimization problem was transformed into a single-level mixed-integer linear programming problem. Finally, case studies were carried out on three real microgrids in China and on BYD-K9 plug-in electric buses. The simulation results indicated that the costs for a plug-in electric bus operator would decrease by 33.35% in the proposed bi-level model compared with the fixed charging model, and the costs for an isolated MG would decrease by 24.16% compared with the model regardless of the plug-in electric buses.

Microgrid in China: A review in the perspective of application

Abstract The paper aims to explore key factors for the development of microgrid from the perspective of application and put forward some new proposals for promoting the microgrid projects in China through the review and extension researching combined approach. The main drivers of microgrid in China are promoting the local consumption of renewable energy, improving the ability to resist emergency, and saving power transmission loss. An overview of experiences with microgrids policies in China shows that optimal capacity planning for microgrid, energy storage technologies, and incentive market policy are key factors to promote the application of microgrid in China.

Research on Microgrid Optimization Based on Simulated Annealing Particle Swarm Optimization

Based on the pursuit of different goals in the operation of the microgrid, it is not possible to meet the lowest cost and the least pollution at the same time. From the perspective of economy and environmental protection, a microgrid model including photovoltaic power generation, wind power generation, micro gas turbine, fuel cell and energy storage device is proposed. This paper establishes a comprehensive benefit objective function that considers both microgrid fuel cost, maintenance management cost, depreciation cost, interaction cost with public grid and pollutant treatment cost. In order to avoid the defect that the traditional particle swarm optimization algorithm is easy to fall into the local optimal solution, this paper uses the combination of simulated annealing algorithm and particle swarm optimization algorithm to compare with the traditional particle swarm optimization algorithm to obtain a more suitable method for microgrid operation. Finally, a typical microgrid in China is taken as an example to verify the feasibility of the algorithm.

Development of smart microgrid powered by renewable energy in China: current status and challenges

ABSTRACTDuring the ‘13th Five-Year Plan period’ (2016–2020), one of the main targets for China's energy strategy is to develop a new generation of power system, integrating high shares of renewable energy sources. This implies that the technology industrialisation of microgrid powered by distributed generation of renewable energy is becoming crucial. This paper carries out a comprehensive study of the status and challenges of developing microgrid, based on case studies of demonstration projects of microgrid in China during different developmental stages. The focus is on the effects of government policies, technical innovations and changes in the business model of electricity market on the promotion of microgrid in China and the reformation of electricity market in China. The ultimate target for the reformation of power system in China is to finish the transformation from a linear business model of centralised power system.

Performance Analysis of the Combined Operation of Interconnected-BCCHP Microgrids in China

From the Internet of Energy point of view, adjacent building combined cooling, heating and power with microgrids (BCCHP microgrids) should be interconnected, which will generate better benefits, both economically and environmentally, from scarce energy resources through intelligent coordination. The interconnected-BCCHP (IBCCHP) microgrids will not only support energy with each other but also bring better benefits compared to the non-interconnected-BCCHP (NBCCHP) microgrids. A mixed-integer linear programming (MILP) economic dispatching approach incorporating piecewise linear efficiency curves model is proposed to compares the performance of IBCCHP microgrids and NBCCHP microgrids. Three buildings with CCHP microgrids in Shanghai are studied as an example, and simulation results are presented to demonstrate that the primary energy consumption (PEC), the carbon dioxide emissions (CDE) and the operation cost of the proposed IBCCHP microgrids are better than the NBCCHP microgrids, and the overall lifetime of the complete battery is improved. Furthermore, a sensitivity analysis is presented to provide various policy recommendations to promote the interconnection among buildings with the change of electricity prices and gas prices.

A Brief Talk of Structure Designing and Actual Application of Microgrid

Nowadays we advocate low carbon economy, energy conservation and emission reduction, emphasize the harmonious development of human being and the nature. As a result, the clean, efficient microgrid with flexible use mode is widely payed attention to. A microgrid uses natural resources as electric power source, it can effectively relieve burden of the grid, and help to solve the problem of transporting electricity from the grid to remote suburb area. How to design the structure of a microgrid to make it run harmoniously with the grid while using clean energy efficiently and controlling the microgrid reasonably is the key to developing microgrid technique. Based on the construction of microgrids in China, this paper concludes the main key techniques in designing and constructing of microgrid, introduces several typical microgrids in China, and makes an outlook to the designing of microgrid structure and technique development.

Policies and demonstrations of micro-grids in China: A review

Micro-grids are effective concepts and systems to interface renewable and sustainable energy resources into utility, which has been paid significant attention. In this paper, the policies and demonstrations of micro-grids for researches and developments, as well as practical applications in China have been comprehensively reviewed. Many recent policies on renewable energy and micro-grids are summarized, which have been guiding and contributing the development of micro-grids in China. Additionally, the available micro-grids demonstrations in China are also introduced in detail. Finally, the emergency necessaries and trends of micro-grid applications in China have been concluded.

Studies from Establishment of a Chinese Provincial Microgrid Standard

A standard is of great importance to microgrid application and development. So far, there is no published standard specifically for microgrids in China except for the Guangxi provincial standard, which is drafted by the authors. This paper focuses on the lessons that the drafters have learned from the standard establishment. The background of making such a standard is introduced first, and its purposes are clarified, as well as the difficulties in standard drafting. Then the structure of this standard is explained, and one technical specification is detailed as an example. Further studies on planning and design of microgrids, multi-microgrids integration and limitations of this standard are discussed. This work can provide reference for establishing a national microgrid standard, thus can stimulate the standardization of microgrids in China and promote their application.

Research on Microgrid and its Application in China

This paper presents the state of the art research and application of microgrid in China, and then introduces the major concerns for the development of microgrid. The research related to microgrid inChinaarose around 2004, focused on the connection of distributed energy resources (DERs) to grid and its influence on distribution network, and then followed the microgrid concept of Consortium for Electric Reliability Technology Solutions (CERTS). However, the microgrid inChinahas taken a more active path with the development of DER and the encouragement of the development of smart grid and resource and energy needing. Now, nearly every province inChinahas typical researches and applications of microgrid. Besides, there are already two major patterns in the development of microgrid, the institute-domi- nating research and the enterprise-dominating application. Research institutions likeTianjinUniversity, Hefei University of Technology, Xi’an Jiaotong University,InstituteofElectrical Engineering(ChineseAcademyof Sciences), etc., are leading the research on microgrid. The companies like State Grid Corporation of China (SGCC), China Southern Power Grid (CSPG), etc., have accomplished several demonstration projects of microgrid, and give a further boost to its application. At the end of the paper, according to the present situation of the development of microgrid inChina, the facing problems and the way to deal with it are put forward.

A Dual-Processor Based Coordinator for Micro-Grid Control and Protection

With the development of micro-grid, the protection and control technologies for micro-grid have withdrawn broad attention. By analyzing the interactions between the micro-grid and the main grid, a dual-processor based coordinator is proposed in the paper. This coordinator achieves the functions of protection and control through two processors, utilizing the electrical information from the whole network, realizing the wide area data sharing and sound cooperation of the unit protection and regional control in the micro-grid. The proposed method enables smooth transition between grid-connected and islanded operation, which is adaptive to any operational modes. Implemented in a demonstrative project of the micro-grid in china, this novel method is verified to be efficient.

Application Prospect and Advantages of Power Supply System Based on 20kV Power Distribution Network and Microgrid in China

In view of high-load density, abundant in wind power and solar energy resources and well-developed areas in the southeastern coastal areas of China, A great number of power system planning problems have emerged. This paper first analyzes the limitations of electric power supply with 10kV voltage level and the advantages of using 20 kV voltage level in distribution network, and then it introduces the status and disadvantages of regenerative energy power to be incorporated into the large grid along the southeast coast of China at present. Finally it is discussed that the advantages of establishing the power supply system based on 20kV power distribution network and Microgrid according to the new resources distribution and the existing problems of medium voltage power distribution in southeast China.