2018, 42(1):1-7. DOI: 10.7500/AEPS20170518001
Abstract:With the construction of ultra-high voltage(UHV)AC/DC interconnected power grid, the advancement of new energy and the deepening of electricity market reform, significant changes have taken place in the operation of power grid in China, which makes higher requirements on the dispatching and control functions. Based on the integrated distribution and concentration deployment scheme of application functions, this paper gives an overview of the new features of the application function, i. e. , global, rapid and accurate, analyzes the technological support to realize such application functions, and points out the urgency of promotion basic work such as power grid model, operation data and management rules.
2017, 41(16):1-11. DOI: 10.7500/AEPS20170219004
Abstract:Considering the new developmental tendency of the state grid including hybrid AC/DC power grids, the access of clean energy, and the power electronics dominated power systems, the changed fault characteristics of modern power systems are analyzed, meanwhile, the challenges and development situation faced by relay protection technology are proposed. Based on this, the principles to be persevered for relay protection technology development are summarized. The emphatic development directions are discussed in detail, namely, the plug-and-play outdoor installation protection, the optimally configured back-up protection, the intelligent operation and maintenance system, three technical supporting platforms of relay protection; the control and protection of high voltage direct current(HVDC)transmission; the forward technologies of relay protection.
2017, 41(9):36-43. DOI: 10.7500/AEPS20170112013
Abstract:With the rapid development of wind power and solar power generation as well as steady development of AC and DC transmission lines, China's power system exhibits two important characteristics and trends: high proportion of renewable energy and AC/DC hybrid power grid in recent years. Based on an analysis of the present development and existing problems concerning collaborative optimization operation of AC/DC hybrid system with a high proportion of renewable energy, the key technologies demanding prompt research in four aspects are proposed, respectively. That is, situation awareness of AC/DC hybrid system under dual uncertainties of source and load, coordinated control of large renewable energy clusters considering the broadband stability constraints, flexible reconfiguration and cooperative operation with the interaction of source-grid-load in distribution systems with a high proportion of renewable energy, and multi-scale operation optimization and decision making in AC/DC hybrid system with a high proportion of renewable energy integrated. Difficulties and challenges are previewed.
2017, 41(19):1-11. DOI: 10.7500/AEPS20170417007
Abstract:The state-of-the-art and typical characteristics of the energy interconnection system(EIS)and microgrid are reviewed from the interpenetration and interrelation perspective of the two systems. Six “cell” functions of microgrids to facilitate the future EIS, namely, improving power quality, enhancing reliability and resilience, coordinating energy dispatch among different areas, achieving load active control and bidirectional information flow, and promoting resources utilization efficiency, are further analyzed from the six features of microgrid including deployment localization, source/load diversification, structural diversity, operational flexibility, controllability, and interactivity. In addition, several typical microgrid interconnection types are presented. Finally, key technologies and equipment to promote EIS development in the future are presented and predicted.
2017, 41(14):2-9. DOI: 10.7500/AEPS20170218001
Abstract:The increasing peak-valley differences, air conditioners and renewable energy sources bring new challenges to the smart grid in China. Demand response(DR)is regarded as one of the most important solutions to the above problems. A new round of electricity market reform is being carried out in China, which provides a good opportunity for developing DR. Under this background, this paper analyzes the development of DR in different electricity market environments. A business model and a market framework of DR, which suit to China's national conditions, are put forward. There are two stages: in the first stage, an ancillary service market which contains DR and is relatively separate with the energy market should be developed; in the second stage, an ancillary service market which contains DR and is collaboratively optimized with the electricity market should be developed. Moreover, product types, price clearing methods, assessment methods and settlement methods of DR are analyzed separately in the two stages. With the development of electricity market in China, DR will play more important role to the stability and economy of the power system.
2017, 41(19):164-175. DOI: 10.7500/AEPS20170126001
Abstract:The research on power grid fault diagnosis is reviewed comprehensively. The sources and characteristics of its data, and the ways and importance of data preprocessing are analyzed. The principle, features and shortcomings of various intelligent diagnosis algorithms are briefly treated, the improvement of research results in recent years are discussed and future study directions are proposed. Then according to engineering practice, the architectural design in the online diagnosis system is summarized. Finally, the problem of power grid fault diagnosis in the background of big data in power grid dispatch and control is discussed, while the development trends are elucidated in the new situation.
2019, 43(3):205-215. DOI: 10.7500/AEPS20180508006
Abstract:Direct current (DC) power grid is effective in solving the problems when high penetration of renewable energy is integrated into the power system. However, the construction of the DC power grid will face challenges in the aspects of technology, equipment and standards. Based on the technical characteristics of DC power grid, three typical application scenarios such as high-penetration renewable energy grid connection, offshore wind power grid connection and DC distribution network are analyzed. The latest research progress of key technologies and core equipments of DC power grids is elaborated. The development direction of DC power grid technology is proposed. The key technologies for the development of DC power grids are analyzed. The future development of DC power grid basic theory system, breakthrough in key technologies and core equipment are pointed out. The above research indicates that DC power grid technology will play a greater role in the global interconnected energy network.
2017, 41(4):48-55. DOI: 10.7500/AEPS20160414005
Abstract:In order to make an accurate assessment of the risk level of urban distribution network, a risk assessing model of distribution network is established and a risk assessment method is proposed. The risk assessing model of distribution network is created in two aspects of operation risk and grid risk. The operation risk reflects the risk level of the current operation state of the distribution network, while the grid risk reflects the potential risks resulting from the defects of the grid structure. Then the corresponding risk assessing index system of distribution network is set up, and the risk quantized values and risk rating are calculated according to the index values. The comprehensive risk level of distribution network is figured out based on the above calculation results, and the variable weights and logarithm compound method are used in the process of calculation. Finally, a numerical example shows that the proposed risk assessment model is feasible and the risk assessment method is effective. The proposed risk assessment model has successfully been adopted by a power supply bureau.
2018, 42(6):1-8. DOI: 10.7500/AEPS20170617001
Abstract:The construction of large ultra-high voltage AC/DC hybrid power grid in China has greatly improved the ability to optimize the large-scale allocation of resources, but it also poses new challenges to the power grid dispatch and control system. This paper analyzes the development situation and characteristic variety of power grids, and new demands for power grid dispatch and control technology support. On this basis, the architecture of a dispatch and control system with the characteristics of physical distribution and logical integration is put forward. Also, the core technologies of basic support, model cloud, big data, dispatch and control based on source-grid-load interaction, integrated security risk prevention and control of large power grid, test verification, and system operation & maintenance, are analyzed in detail.
2017, 41(13):182-191. DOI: 10.7500/AEPS20161123001
Abstract:High penetration of distributed generators, controllable loads, such as electric vehicles, energy storage systems, and access and application of sheer number of measuring devices present the state estimation program of active distribution network with many challenges in accuracy and efficiency. Firstly, this paper briefly summarizes the existing research results of traditional distribution network state estimation. Then the research status of examining state estimation technique in active distribution network is comprehensively presented, including the modeling of novel pseudo-measurements, the efficient improvement of the state estimation algorithm and the optimal meter placement. Finally, several aspects that should be focused on in future development of state estimation of active distribution networks are outlined.
2017, 41(24):184-192. DOI: 10.7500/AEPS20170609003
Abstract:The future distribution system will have the significant characteristics such as high density integration of distributed generations, interconnection of AC/DC hybrid system. Therefore, the fault analysis for distribution system will face new challenges. As the integration of high density distributed generation and power electronic equipments, the fault response presents the property of nonlinear temporal-spatial correlation, and the fault response interaction influences between AC/DC system further increase the difficulty of fault analysis. In this paper, the current research status of the distribution system fault analysis is summarized, and the key issues to be studied in the future are proposed including the analysis and decoupling modeling of distributed generations for the temporal-spatial correlation characteristics, the equivalent modeling of AC/DC hybrid distribution system, and the effective convergence algorithm.
2018, 42(21):10-20. DOI: 10.7500/AEPS20180331006
Abstract:As the link of the energy and electric power system, the effective state evaluation of the power equipment is a powerful guarantee for the stable operation of power system. Based on the existing research results and the perspective of data science, this paper makes an in-depth analysis of the methods in the field of state evaluation of power equipment. Firstly, the paper introduces the new characteristics of state evaluation of power equipment in the context of data science. Then, with the current well-known data science analysis method based on data analysis technology as the starting point, the paper presents the key issues of the state evaluation of power equipment in data preprocessing, calculation and analysis, storage, and visualization. In addition, the paper systematically expounds the specific application, bottleneck and future development of data science in the field of state evaluation of power equipment. Finally, the paper discusses the challenge of data science in the state evaluation of power equipment and anticipates some directions of future research work in this field.
2017, 41(17):148-154. DOI: 10.7500/AEPS20161223004
Abstract:After the characteristics and functional demands for network management in the new generation smart substation are analyzed, the overall framework and function deployment scheme of the communication network management system are proposed by cutting down the architecture and functional model of the telecommunication network management system. The key technologies of the network topology automatic mapping, service of automatic discovery and creation, visualization of physical loop and virtual loop are also developed. With the Fengqiao substation project in Shaoxing City as an example, the feasibility of the proposed scheme is verified. After the scheme is widely used, the capabilities are enhanced and the costs are reduced in the operation and maintenance management system.
2018, 42(22):2-10. DOI: 10.7500/AEPS20180502008
Abstract:During the development transition period of China's ultra-high voltage(UHV)power grid, the characteristics of power grid continue to change significantly. The traditional defense technologies and measures on security and stability are difficult to adapt, thus the security prevention and control system is needed to improve. The necessity and demand of “system protection” to adapt to construct UHV AC/DC power grid is put forward based on the characteristic-changes of power grid. The design of system protection is proposed, including design ideas, overall composition and specific measures. Then the key technologies of system protection are put forward, and the requirement and framework of panoramic state perception, real-time decision-making and coordinated control as well as precision load control technology are focused on. Finally, the implementation scheme of system protection construction for State Grid Corporation of China is briefly illustrated, which provides a solution for the safe and stable operation control of large-scale UHV AC/DC power grid.
2018, 42(2):1-10. DOI: 10.7500/AEPS20170625002
Abstract:Power transmission of high voltage, large capacity and long distance, adverse meteorological environment, AC/DC fault coupling propagation, a large number of application of power electronic equipments and other factors have brought new challenges to power system protection and security control. Firstly, the causes and the types of transmission and trans-formation equipment faults, as well as the difference in fault consequences are analyzed in this paper, and the technical system of pro-active protection and control(PPC)of power equipment is proposed. Then, the concepts of security region, dynamic security margin and tolerance time for safety of power transmission and transformation equipment are proposed to describe the safety of equipment as the main features. The technical architecture of pro-active protection and control is further proposed cored on the prediction of security region and security parameters of equipments. Finally, main technical directions of the pro-active protection and control are analyzed in this paper, and feasibility of the corresponding key technology, and prospect of the pro-active protection and control are discussed.
2018, 42(6):106-112. DOI: 10.7500/AEPS20170614011
Abstract:Firstly, a typical topology structure and node classification of flexible DC distribution network(FDCDN)are described. Secondly, a hierarchical coordinated control architecture for FDCDN is proposed. The system-level control adopts elite strategy based non-dominated sorting genetic algorithm with the embedded probabilistic load flow and the converter-level control uses multi-stage DC voltage margin control. The source-load-level control adopts the “quasi-cocktail” source-load response strategy to minimize the terminal power control error. Finally, a simulation model of FDCDN is established on the RTDS&dSPACE combined simulation platform. The effectiveness of the proposed hierarchical coordinated control strategy is proved by simulation.
2018, 42(2):84-91. DOI: 10.7500/AEPS20170320005
Abstract:With the rapid development of UHV AC/DC power grid, the connections between power sending-side and receiving-side, AC and DC, and the upper and lower levels of the dispatch center are becoming closer and closer. The risks that local faults spread to the whole power grid are increasing, and the difficulty of dispatching real-time operation control is significantly also increasing. In this context, the paper analyzes the challenges and needs of real-time operation control of UHV AC/DC power grid, and combs out the problems and shortcomings of previous dispatching control system for supporting the operation control of UHV power grid. On this basis, the overall goal, the overall framework and the main modules of the integrated operation monitoring and fault co-processing application of the UHV interconnected power grid application function are proposed. Then, the related key technologies are analyzed and demonstrated, such as the operation status of the UHV power grid with the same monitoring of different dispatch centers, the coordination fault diagnosis of cross-regional power grid, the multi-level fault disposal joint implementation, fault information integration and multi-screen linkage display, “generation-grid-load” optimization coordination, provincial and prefectual power grid load coordination control and so on. Combined with the engineering practice in the relevant dispatch center of the UHV sending side and receiving side, the practical application effect is introduced. Finally, the future development directions and key technologies in the field of dispatching control of UHV power grid are discussed.
2018, 42(7):2-22. DOI: 10.7500/AEPS20180209010
Abstract:With the increasing demand for the controllability and flexibility of primary equipment in power system and the fast development of power electronic technology, more and more power electronic equipment is applied. In this paper, power electronic primary equipment in power system is collectively called flexible primary equipment. From this point of view, this paper firstly reviews the research progress and engineering applications of flexible primary equipment and their key technologies in flexible AC transmission system, flexible DC transmission system, renewable energy power generation, power energy storage, active distribution system and microgrid. Then the key generic technologies of flexible primary equipment are analyzed, and its development trend is prospected.
2018, 42(3):149-159. DOI: 10.7500/AEPS20170320007
Abstract:The concept of power system high-performance computing mode is illustrated. Following the evolution direction of off-line computation to on-line cooperation, the high-performance computing modes of parallel computation, distributed computation and cloud computation are mainly analyzed to improve the calculation speed and reliability, and provide the computing service. From the aspects of decomposition coordination methods, numerical parallel computing, hard-computing architecture and soft-computing mode, the overview of state estimation, power flow calculation, and online dynamic security analysis(DSA)including the transient stability computation and static safety analysis function are summarized. Three evolution phases to realize on-line computing cooperation roadmap are described, and the key technologies including assignment-mapping mechanism, decomposition-coordination computing service, module service interface and data interaction format are discussed in detail to support the on-line cooperation computation mentioned above. In the end, the on-line cooperation analysis computing scenario and state estimation service mode are designed in the cloud computing environment, which provides a reference for the cloud computing based design and development of dispatching control system.
2018, 42(18):1-7. DOI: 10.7500/AEPS20171124001
Abstract:The new challenges facing grid monitoring and control in its own development needs and changes in the external environment are teased out. The new requirements of surveillance control, such as global awareness of the power grid, prevention and control of global risks, unified and coordinated control at multiple levels and flexible adaptation to external environment changes are clarified. In view of the new challenges and new demands, a new mode of global supervision and control of large power grid is proposed, which points out that it needs a wider range of surveillance, more types of surveillance content, more powerful real-time data processing capability, higher data real-time and consistency and other specific content. Based on the concept of “physical distribution and logical unification”, the overall framework of global monitoring is designed, and the key technologies that need to be further studied to realize the new mode are given.