Three tower heliostat field layouts, EB, No blocking-dense, and DELSOL derived from the radial staggered layout and the principle of no blocking loss, were studied. After summarizing the mathematical models of the three heliostat field layouts, combined with some design parameters of Gemasolar power tower plant, the software SolarPILOT was used to model and simulate the heliostat field according to the three layout modes. MATLAB was used to process the coordinate data of the heliostat field obtained by the modeling, and the change curves of radial spacing and azimuth spacing were obtained, so as to verify the rationality of the three layout mathematical models. The layout rules of the heliostat ring were obtained by analyzing the arrangement characteristics of the basic ring and the staggered ring in each heliostat field. At the same time, the performance of different layouts was compared from the number of heliostats, the optical efficiency, the land utilization ratio and the receiving energy of the heliostat field, and their advantages and disadvantages were analyzed. The results show that in the range of 1 000 m radius of the heliostat field, the average annual optical efficiency and land utilization rate of the heliostat field under the No blocking-dense layout are the highest, followed by the EB layout. However, the number of the heliostats and the receiving energy of the heliostat field under the EB layout are the largest, and the performance characteristics of the DELSOL layout are the lowest.

The new generation of artificial intelligence driven by big data has shifted from traditional knowledge representation to deep and autonomous learning. It no longer requires too much human intervention and shows a smarter side. In recent years, deep learning (DL) has become the hotspot of artificial intelligence. This paper focuses on the characteristics, principles and the current application status of DL in the power system. It also analyzes the research trends and problems in the application process of the new generation artificial intelligence, and provides solutions based on distributed machine learning and incremental learning methods. This paper is written for providing references for researchers involved in the field.

The method of urea pyrolysis for ammonia denitrification has been widely used in the denitrification technology of thermal power plants due to the safety of raw materials and the maturing technology. However, crystallization of the pyrolysis furnace occurs frequently. In order to avoid crystallization and environmental events, based on the experience of operation, the judging basis and treatment method of the crystallization of the pyrolysis furnace were introduced. The causes of the crystallization from the point of view of system design and operation adjustment was expounded. The optimization scheme of the system design for the pyrolysis furnace and operation adjustment methods was given. The engineering practice shows that timely and accurate crystallization judgement, effective operation adjustment method and optimized heat release nitrate system can effectively prevent the crystallization of the pyrolysis furnace and eliminate the occurrence of environmental protection events.

Supercritical CO₂ cycle has a high cold end temperature. Optimizing the cold end temperature plays an important role in improving the cycle efficiency. In order to obtain the best annual average efficiency, it is necessary to introduce artificial refrigeration to make the supercritical CO₂ cycle run at a more optimized cold end temperature. For the supercritical CO₂ recompression cycle with parameters of 550℃/20MPa, the annual average cycle efficiency under different cold end temperature of 5 to 35℃, with the combination of natural cooling and artificial refrigeration was analyzed by thermodynamic method, and the feasibility and economic analysis of the cold end temperature optimization method were studied as well. The annual average efficiency of the unit can be improved by choosing the optimal cold end temperature and combining natural cooling with artificial refrigeration. For northern China, the cold end temperature optimization method has better feasibility. The artificial refrigeration increases the investment of unit equipment, but the improvement of operation efficiency brings more power generation revenue and moreover increases the net income of the unit during its life cycle.

Metaverse is a new internet application and social form of virtual reality integration which is produced by integrating a variety of new technologies. With the goal of “carbon peak and carbon neutrality” and the proposal of new power system, the construction of power system in metaverse is the trend in the future. Considering the application of metaverse applications in power systems, this paper used digital twin technology and internet-of-things technology to understand the metaverse, and then analyzed the power systems in the metaverse. Different from the current virtual reality, the metaverse has four characteristics: virtual fusion, diversification, immersion, economic system and civilization. Focusing on the above two means and four characteristics, this paper introduced the metaverse from the perspective of science and engineering, and expounded the framework and functions of power systems. Finally, this paper discussed the potential applications and prospects of metaverse in power systems.

On February 15 and 16, 2021, a winter storm swept across Texas, causing a destroying rotating blackout. The blackout has affected about 4.5 million residents, and the price on spot power market soared sharply, resulting in a great damage on the economic and social order. On February 24, the Electric Reliability Council of Texas (ERCOT) released its first report of the blackout incident. Based on the report, a brief overview of Texas power grid and the development process of the whole blackout event were introduced firstly. Then, this paper analyzed the causes in detail. Finally, some suggestions on how to construct China power gird with the goal of achieving "carbon peak, carbon neutral" were proposed.

Aiming at the problems of inefficient manual detection of wind turbine (WT) blades and difficult diagnosis of defects, a method of defects detection for WT blades based on unmanned aerial vehicle (UAV) and image processing is proposed. Through the joint development of Halcon 12 and Visual Studio 2015, the functions of image processing flow, test result output and defects playback are realized, including camera calibration, image processing through fast adaptive weighted median filtering and dynamic threshold segmentation. Through the regional processing to identify defects such as cracks and trachoma, the defects are classified and measured, and the analysis report of WT blades quality can be output to finally realize the automatic detection function of the surface defects of the WT blades. The high accuracy and stability of the algorithm of this method in detecting WT blades surface defects are demonstrated experimentally.

The removal efficiency of ammonia in denitrification downstream equipment, concentration and distribution mechanism of ammonia in fly ash and slurry were studied under the condition of high concentration of ammonia escaping from denitrification by selective catalytic reduction (SCR) in coal-fired power plants. Through sampling analysis of 350 MW and 600 MW units, the results show that: the escaping ammonia removal efficiencies of air preheater, electrostatic precipitator and wet desulphurization system are 3.37%-6.63%, 75.14%-83.28% and 36.36%-46.38%, respectively. The ammonia removal efficiencies of these downstream environmental protection equipment are high, and the ammonia concentration at chimney entrance decreases obviously compared with that at denitrification outlet. The ammonia content in fly ash is inversely proportional to the particle size of fly ash. Ammonia concentration in desulfurized flue gas increases with the increase of ammonia concentration in original flue gas. The removal efficiency of ammonia in desulphurization system decreases with the increase of slurry pH value. The results have great significance to the units’ environmental protection and economic running.

As a secondary energy, hydrogen energy will play an important role in the future energy system dominated by renewable energy because of its green, flexible and wide-ranging characteristics. The core of large-scale development of hydrogen energy industry is to realize low-cost and efficient raw material source, storage and transportation. Therefore, a review was made on the key technologies of how to truly realize the clean and efficient utilization of hydrogen energy in the aspects of hydrogen production from renewable energy electrolyzed water and hydrogen storage and transportation. The ideas and progress were summarized in the development of hydrogen energy in Europe and Japan as the leading countries for hydrogen energy utilization, and also the cost factors of hydrogen energy were discussed. The development trend of hydrogen energy in China was analyzed, and the development prospect of China's hydrogen energy industry in the future was also put forward, the suggestions were as follows: establishing a sound legal and policy system; paying attention to the development of hydrogen supply and storage and transportation; actively exploring and developing various ways of hydrogen energy utilization.

High temperature solid oxide electrolysis cell (SOEC) is a new type of high-efficiency electrochemical energy transfer device with high energy transfer efficiency, high reaction rate and wide application scenarios. It has enormous potential in the fields including production of low-cost green hydrogen and carbonaceous product with high added values. Nitrogen oxide treatment _{and ammonia synthesis may also be a promising direction of application. SOEC is expected to play an important role in the low-carbon transformation of energy, chemical industry, transportation and other fields. Based on the latest progress of SOEC in the fields of hydrogen production, oil production, nitride treatment and ammonia production, the development status of SOEC was systematically summarized, and the key directions for future development were prospected.}

The ubiquitous power internet of things(UPIoT) is a complex multi-network system composed of a power system and a combination of intelligent terminal sensors, communication networks, artificial intelligence, and cloud platform technologies. It is with the characteristics of holographic perception, ubiquitous connectivity, open sharing, and fusion innovation. This paper firstly expounded the basic concepts and characteristics of UPIoT, and analyzed its architecture in detail, including the technical architecture, standard architecture, and application architecture. Next, it discussed the key technologies of the ubiquitous power internet of things including intelligent chips, 5G and LPWA, internet of things platform. Afterwards, key difficulties such as business barriers, cyber security, data analytics, and business modes were explored. The actual needs and application prospects of ubiquitous power internet of things were studied.

Proton exchange membrane fuel cells take advantages of high efficiency, no pollution and good fuel adaptability. The green energy network formed by combining fuel cells with reliable hydrogen production is an effective way to achieve carbon neutrality. It is expected to promote the technological research and upgrading of new energy vehicles, unmanned air vehicles, ships and other industries those use fuel cells as electricity and thermal power source. However, a safe and stable hydrogen supply technology is a major bottleneck limiting the development of fuel cell power generation applications in mobile scenarios. Hydrogen production by in-situ methanol reforming is hopeful to make a breakthrough in mobile hydrogen source technology based on fuel cell. In this paper, the research progress of methanol reforming hydrogen production, the research progress of reactors for methanol reforming hydrogen production and the application of methanol reforming fuel cell power generation system were reviewed to provide reference and guidance for promoting the commercial development and application of methanol reforming fuel cell in the field of new energy.

Aimed at the phenomenon of wind turbine blade icing, which is easy to occur in the cold areas, a method of icing detection of wind turbine blades using SCADA data was proposed. When the blades are icing, the power loss of generator will be increased, thus the method picks two variables, wind speed and power. Principal component analysis (PCA) was used to construct the projection feature on non-principal component direction which is sensitive to icing and active power of network. By choosing the optimal threshold, the logistic regression classifier is suitable for unbalanced classification. The effectiveness of this method was verified by the data of China Industrial Big Data Innovation Competition.

The concept of "environmental protection island" was proposed in view of the current situation of environmental protection of thermal power plants. The "environmental protection island" of thermal power plants includes the environmental protection of "gas-water-solid-noise" four pollutant groups happened in the field of thermal power plants. It was thoroughly combed the relationship between the production and control of various pollutants and technical means, thus, an in-depth comparison of the key technologies were made which involved in the transformation and operation. Several corresponding technical routes and technical viewpoint was put forward, and the concept of "environmental protection island" for thermal power plants was formed. It is a good reference for the environmental protection work of thermal power plant.

Solar photovoltaic/thermal (PV/T) technology is the integration of PV modules and solar collectors, which can simultaneously generate electricity and provide thermal energy. The overall efficiency and the space utilization efficiency will be improved simultaneously by the combination of two modules. The types of PV/T technology and related theoretical researches were summarized firstly in this review. By focusing on the heat loss and overtemperature problem of flat-panel PV/T technology, the design progress has been reviewed and analyzed. The state-of-art study on integration of phase change materials with PV/T (PV/T-PCM) technology was comprehensively summarized. The deficiencies in the research and the future development tendency were also prospected in order to provide theoretical guidance for further development of PV/T systems.

Based on the finite volume method in computational fluid dynamics, the performance of the trough solar thermal power collector with Al₂O₃/Syltherm800 oil nanofluid as heat transfer fluid was studied. A three-dimension model of the vacuum collector was established, optical simulation and heat transfer numerical simulation were carried out and verified by experiments. Under the condition of non-uniform heat flux distribution, the influence of inlet temperature and inlet velocity on the heat transfer performance of the trough collector with nanofluid was studied. The simulation results show that the heat transfer performance and heat efficiency of the trough collector are improved with the increase of Al₂O₃ volume fraction. The heat transfer performance of the collector is greatly influenced by the inlet temperature and the inlet velocity. With the increase of inlet temperature and the decrease of inlet velocity, the influence of the nanofluid on the heat transfer performance increases gradually.

Accurate estimation of state of charge (SOC), battery state of health (SOH) and prediction of battery remaining useful life (RUL) of lithium-ion battery are important contents of battery management. It is of great significance to prolong battery life and ensure the reliability of battery system. Researchers all over the world have done a lot of research on battery state evaluation and RUL prediction methods, and proposed a variety of methods. This paper first introduced the definition of SOC and SOH and the existing estimation methods and compared them. Then, the definition of RUL was introduced and the main methods were classified and compared. Finally, the challenges of lithium-ion battery state estimation and RUL prediction were summarized, and the future development direction was proposed.

The pipelines of the EH oil system of the steam turbine are connected to the oil supply system, emergency shutoff system and the implementing agency to form the entire circuit. As the transmission channel of the oil medium, once a leak occurs, it will directly cause the unplanned outage of the generator set, which will result in huge losses of economic benefits and social benefits for the enterprise. A few typical cases of EH oil pipeline leakage occurred in thermal power generation units recently. In this paper, several types of failure mechanisms that are common to EH oil pipelines were summarized from the perspective of metal materials. Combined with each typical case, the failure analysis process and its focus were introduced briefly. And from the technical supervision point of view, the paper puts forward the governance and preventive measures importantly, specific to the corresponding inspection methods and inspection contents, which fit the scene for reference.

Due to the randomness, volatility and anti peak characteristics of wind power, a high proportion of wind power penetrating into the power grid will have a great impact on the stability and security of the power system. Therefore, it is necessary to control the active power of the wind farm to reduce the fluctuation and improve the smoothness of the output power. With the increasing installed capacity, a large number of wind curtailment occur, and the control mode of wind farm is changed from the traditional maximum power point tracking (MPPT) mode to the limit power control mode. The necessity of controlling the active power of the wind farm was analyzed, based on the backgrounds of the control requirements of the wind power connected to power grid and curtailment. Starting from the single machine power control and station level power control, taking the station level power control as the emphasis, the research status of active power control of wind power was summarized. The control characteristics and shortcomings of different control methods were summarized, and research directions were prospected.

In the past three decades, China’s power industry has developed rapidly and solved the problem of efficiency and cleanliness to a certain extent. However, the implementation of the “double carbon” target has put forward the requirements of low carbon development for China’s power industry. Improving energy utilization efficiency, increasing the proportion of zero-carbon energy and carbon-neutral energy, and equipping carbon capture, utilization and storage (CCUS) technology are three important ways to achieve carbon emission reduction in the power industry. Based on the carbon neutral formula of power system, the carbon emission reduction history of China’s power industry and the carbon emission reduction contribution of different pathways between 2000 and 2020 were analyzed, and the current situation and routes of CCUS technology development in China were described. The results show that between 2000 and 2011, improving the efficiency of carbon-containing energy utilization made the main contribution to carbon emission reduction in the power industry, and after 2011, the increase of the proportion of zero-carbon energy contributed more to carbon emission reduction in the power industry. To achieve the goal of carbon neutrality in the power industry, CCUS technology is indispensable when the fossil energy cannot be completely replaced. Currently, the high cost and energy consumption of CCUS technology are the main reasons that hinder its promotion. The fuel source capture technology realizes the graded utilization of energy and the enrichment of carbon components, which reduces the energy consumption of CO₂ capture, and the efficiency of fuel source carbon capture system can generally be improved by 5 to 8 percentage points compared with the current mainstream carbon capture technology.

A kind of connection scheme of three-terminal back-to-back (BTB) voltage source converter based HVDC(VSC-HVDC) system in 10 kV distribution network was discussed, which can improve the reliability of power supply and restrain the circulation by the control of VHC-HVDC. With the traditional control strategies, VSC-HVDC system has almost no interia and is hard to be involved in the dynamic regulation of the power system effectively. To improve the stability of the frequency in the receiving system and improve the performance of the system after the breakdown, the control strategy of virtual synchronous generator (VSG) in the application of three terminal back-to-back VSC-HVDC under a medium voltage (10 kV) AC distribution network context was proposed. First three terminal back-to-back VSC-HVDC device was added to the 10 kV system to establish the AC/DC hybrid distribution network, and the mathematical model of the converter under the traditional control and VSG control was established. Then the simulation was carried out by using the PSCAD/EMTDC platform, the operating characteristics of disturbance and fault were obtained in two control modes. The results show that the three-terminal back-to-back VSC-HVDC system can effectively participate in the regulation of power grid system using VSG control, and gain the interia to improve the system's performances of transient states, and the reliability of the grid are effectively improved.

Permanent magnet eddy current heating is a heating form using wind energy. Because of its low requirement on wind quality, relatively simple device structure and high heating efficiency, it is an effective application of distributed energy. Taking the permanent magnetic eddy current heating device as the research object, the input torque of the heating device, which was deduced according to the principle of electromagnetic field, was compared with the input torque of the vertical axis wind turbine. A mathematical model of the relationship between the geometric parameters of different components inside the device was established, and the components of the permanent magnet eddy current heating device were determined, which provides a theoretical basis for the design of a more reasonable permanent magnet eddy current heating device structure.

In view of the unstable performance of the cold-end system of traditional power plants and the high annual operating cost, a mathematical model based on the heat, resistance, civil construction and annual operating cost calculation of the direct flow cold end system based on negative digging depth was established, and the cold end system configuration was obtained from different conditions outside the tower. The optimal configuration was used to analyze the effect of cooling water for intlet tower water temperature, coagulator area unit price and condenser negative digging depth on the performance of cold end system. The results show that reducing the cooling water for intlet tower water temperature and condenser area unit price can reduce the annual operating cost of cold end system. The performance parameters of the cold end system with a negative digging depth of 3 to 5 m reach the lager value. Therefore, selecting the cold end system configuration according to different weather parameters outside the tower can improve the operating efficiency of the power plant and reduce the annual operating cost of the cold end system.

It will lead to the problem of frequency adjustment when the large-scale new energy integrated in the power grid, and large capacity power energy storage is one of the effective solutions for the problem. By analyzing the types of power energy storage and its application scenarios, this paper points out that there are four large capacity energy storage technologies such as electrochemical energy storage, pumped storage, flywheel energy storage and compressed air energy storage which play a role in the power grid frequency adjustment, introduces the performance feature of the four large capacity power energy storage, and summarizes the properties which participate in grid load adjustment, primary frequency modulation, secondary frequency regulation. The characteristic of peak frequency modulation are compared, and the development tendency of research in the future is pointed out.

Ultra high voltage direct current (UHVDC) projects have been widely constructed in China power grid. A model of the evaluation factor set that affects the operation of UHVDC project was built and the current operation conditions of UHVDC project was evaluate based on this model. Firstly, an evaluation model of UHVDC project was constructed based on the development process of UHVDC project by employing the analytic hierarchy process (AHP) to determine the weight of evaluation factors and contribution weight method to quantify the mutual influence between different development processes. Then, an UHVDC project in Gansu Province was taken as an example to build its evaluation model, expert evaluation method was used for quantitative evaluation according to various specific factors, and the evaluation results with visual and graphical methods were analysed. Based on the problems of the UHVDC project and other UHVDC projects in China, the suggestions for the safe and high-efficient operation of UHVDC projects were proposed aiming to provide reference for the future development of UHVDC in China.

As an important part of carbon capture, utilization and storage(CCUS) technology, CO₂ sequestration in saline aquifers is an effective means to achieve the goal of carbon neutralization. Improving the research scheme of CO₂ sequestration mechanism in saline aquifers is of great significance to accurately evaluate the storage potential. The storage mechanism of CO₂ sequestration in saline aquifers was discussed, the commonly used characterization techniques were summarized, the effects of different parameters on sequestration in saline aquifers were discussed, and the future development of this technology was prospected. According to the study of different storage mechanisms, the characterization technology of sequestration in saline aquifers mainly includes reservoir rock characterization, core flooding experiment, solubility experiment, mineralization reaction experiment and so on. The storage potential of CO₂ sequestration in saline aquifers is affected by many parameters, such as the residual water saturation, residual gas saturation, solubility and salt precipitation. Therefore, it is very important to select appropriate characterization techniques to determine the relevant parameters to ensure the accuracy of storage potential evaluation. In addition, the analysis of the whole process storage mechanism and the research of marine CO₂ sequestration in saline aquifers project are the important research direction of this technology in the future.

Proton exchange membrane (PEM) water electrolysis is a green and sustainable method of hydrogen production. The development of efficient and economical electrocatalysts for anodic oxygen evolution reaction (OER) is the key to its large-scale commercialization. Iridium oxide catalysts supported by different manganese based oxide carriers (IrO _x /Mn₈O₁₀Cl₃, IrO _x /β-MnO₂ and IrO _x /α-MnO₂) were prepared by two-step synthesis method, and the content of iridium is about 55%. Compared with the commercial IrO₂ and other noble metal containing electrocatalysts, the synthesized catalysts have lower overpotential and higher current density. The overpotential of IrO _x /β-MnO₂ is only 228 mV at the current density of 10 mA/cm². The specific mass activity of IrO _x /Mn₈O₁₀Cl₃ reaches 916.7 A/g_Ir at 1.53V. The enhancement of OER activity is attributed to the abundant hydroxyl oxygen defects and Ir^III species on the catalyst surface. The rich crystalline-amorphous interface provides a large number of active sites for the reaction. The iridium oxide/manganese based oxide catalysts reported in this paper provide new insights for the development of efficient and economical catalysts for acidic OER.

Power information systems are important for the operation of power systems. When part of the power information system fails, the loads will be redistributed. Due to network congestions, cascading failures may occur, and additional devices or sub-systems would fail. In this paper, power information system was abstracted to a complex network. The traditional load-capacity model was improved to satisfy the characteristics of power information systems. The improved model also reflects the distribution of power information system nodes. Moreover, two vulnerability indices were established from the perspective of both topological structure and network properties, and the vulnerability assessment process was proposed. Finally, cascading failure process and the impact of redundancy factor were analyzed in case study. The effectiveness and rationality of this method was verified by the results.

The penetration of distributed energy in the distribution network is increasing, which has caused great pressure to the power grid. The combination of energy storage and distributed generation system can reduce unstable electric energy into the network, reduce the impact of photovoltaic power on the power grid and improve the capacity to accept new energy. In view of the necessity of energy storage and the economic problems of projects, a comprehensive life cycle assessment model was established. This method studies the economy of the system from the aspects of project cost, annual income, total profit, static investment recovery period, and evaluates the social benefits of the project. The example shows that the utilization of power generation is high, the annual net income increases obviously, and its economy is less dependent on the electricity price and the degree of electricity subsidies. With the development of photovoltaic and energy storage, systems without energy storage will no longer have economic advantages, and the photovoltaic energy storage system has greater potential for development. Finally, combined with the experience in foreign countries, suggestions are put forward from the benefit feedback, electricity price incentives and financial support, so as to promote the healthy development of distributed photovoltaic industry.

Cabinet A and cabinet B of generator protection group of a power plant respectively reported "protection action of stator zero sequence high voltage section", which caused unit trip. It was found that the generator outlet potential transformer(PT) B phase 5042PT was obviously overheated. The accident process, through the breakdown PT finish straight resistance, insulation, excitation characteristic curve, and no-load current test, PT interturn short circuit are the main reasons of the unit tripping. In view of how to find early export PT insulation fault, the corresponding measures to prevent cracking was proposed. Specification requirements must be strictly according to the forecast to complete generator export PT partial discharge, triple frequency withstand voltage test, etc. In addition, the trend analysis was carried out on the data of various routine pre-test projects to detect the abnormality timely. The analysis of PT turn-to-turn short circuit fault at the generator outlet plays a good role in finding out the safety hidden danger and improving the reliability of the equipment. The regular completion of relevant tests in accordance with the standard requirements and the emphasis on the trend analysis of test data can effectively reduce the occurrence probability of the same type of accidents and reduce the scope of accidents.

The new power system with high proportion of new energy and power electronic equipment is an important means to achieve the goal of “double carbon”, but the new power system will also bring a series of unstable problems. In the new power system, grid-forming control technology (GFM) has the characteristics of voltage support and active inertia, which can replace synchronous machine to realize grid support and maintain power system stability. Therefore, GFM has a broad development and application prospect. Based on this, this paper first briefly introduced the topology of energy storage converter, and selected its type according to the control characteristics of GFM technology. After that, a reasonable summary and analysis of the existing control strategies of GFM was made, the current research difficulties, problems and challenges in the development process and the research prospects were put forward, and the ideas for the construction of grid-forming construction were provided.

China has set a goal of reaching a carbon peak by 2030 and becoming carbon neutral by 2060. Based on the 2050 global energy interconnection (GEI) scenario and backbone grid plan, such issues in the construction of the GEI as high proportion of clean energy, connecting pattern and grid structure, operation control measures, etc. were studied. The proportions of clean energy, implementation path and responding measures to challenges were analysed, the concept of multi-node and multi-loop generalized backbone grid were proposed. The hierarchical and zoning structure was discussed, and intelligent dispatching, stability control, information communication and big data and other operational control measures were proposed. Key technologies such as large-capacity long-distance power transmission, cross-sea power transmission, clean energy power generation, and energy storage were analysed and predicted.

With the gradual deepening reform of the power system and the gradual improvement of the power market trading mechanism, it provides a new opportunity for the development of energy storage technology, and the energy storage technology presents a good trend of diversified development. The establishment of an auxiliary service compensation mechanism has accelerated the penetration of energy storage systems in the auxiliary service field. The auxiliary service market has become one of the main application directions of energy storage technology. The participation mechanism was investigated, the status of energy storage technology in auxiliary services were researched, and the application scenarios and main research directions of energy storage technology in power system auxiliary services were summarized. At the same time, combined with the construction of the ubiquitous power internet of things, the business model of energy storage participating in auxiliary services in China was discussed.

According to electric power development the 13th five-year plan and related national policies and legislations, we analyzed coal-fired power units' design technology trend in China in the future and concluded that the core of coal-fired power units' development would be clean coal power generation in the next five years and focusing on low carbon coal power generation research at the same time. During the 13th five-year plan, ultra supercritical coal-fired power generation with higher parameter, ultra-low emission reconstruction in fault coal-fired plants, flexibility and energy saving reconstruction, deep water conservation and biomass co-combustion in large coal-fired boilers have certain development space, and more suggestions are emphasized on technology research areas.

Artificial intelligence was widely used in power systems. It has improved the security, reliability and operation ability of power systems. The related work in the early, middle and late stages was summarized including expert system and neural network and so on in the 1980s and 1990s and relevance vector machine in the early 21st century. The characteristics, principles and application in power systems of relevant vector machines were mainly introduced.

This paper reviewed the current development research of China’s offshore wind power industry in the field of integrated design of wind turbine, tower and foundation. This paper explored the feasibility of integrated design from the aspects of load reduction optimization technology, structural optimization technology and engineering exploration and application, and discussed the key technologies and implementation methods of integrated design that can be adopted under the optimization goal of lightweight offshore wind turbine support structure. The research shows that China’s offshore wind power industry needs to be gradually implemented from three levels: providing the prerequisites for integrated design, using the technologies that can be adopted at the current stage,and exploring the next research directions. In the context of offshore wind power moving towards grid parity, owner-engineers and third-party certification bodies need to play a greater role in promoting the integrated design method.

Aiming at the problem of excessive vibration of the stator end winding of the imported large turbo-generators, an active frequency modulation control method of the stator end winding vibration based on the change of temperature field was proposed. Taking the fixed-hinged straight beam as an example, the influence mechanism of temperature field on natural frequency of structure was studied, and a test plan was designed. The results show that by adjusting the temperature of the stator cooling water and cold hydrogen, the natural frequency of the stator end winding is far away from the electromagnetic excitation frequency and the resonance region is avoided, thereby effectively reducing the vibration of the stator end winding. Finally, the active frequency modulation control logic module based on temperature field thermal stress was developed, which provides a new method for controlling the vibration of the stator end winding of turbo-generator.

Direct at the problem of only one turbine's waste heat can be recovered in typical double-units configuration power plant, the waste heat quantity of the wet cooling unit and the present technologies' ability to recover waste heat were analyzed quantitatively. A heat supply system that absorption heat pumps in series low pressure cylinder with bare-shaft to recovery waste heat from circulating water was presented. And the system to recover waste heat of steam turbine driving feed water pump was also proposed. With the system, all the two units' waste heat could be recovered to supply district heat for the typical double-units configuration power plant.

Hydrogen energy has broad development prospects as a clean, carbon-free, flexible and efficient secondary energy and industrial raw material. Although the technologies of hydrogen production by water electrolysis, hydrogen storage and hydrogen supply have been relatively mature, the technology chain of hydrogen production-storage-supply is still in its infancy. It is of great importance to explore the technology chain in power system for the cooperative utilization of hydrogen energy and traditional electricity. This paper firstly introduced the basic principles, classifications, advantages and disadvantages of the technologies including hydrogen production by water electrolysis, hydrogen storage and hydrogen supply, and summarized the development of hydrogen production by water electrolysis, hydrogen storage and hydrogen supply technologies in the United States, Japan and the European Union. Then, the current status of above technologies in China was analyzed, and three possible application modes of hydrogen production by water electrolysis, hydrogen storage and hydrogen supply in power system in China were discussed. Finally, based on the current situation, the suggestions for promoting the development of hydrogen production by water electrolysis, hydrogen storage and hydrogen supply in power system in China were put forward, which provide a reference for optimizing the development of the whole technology chain of hydrogen energy production-storage-supply-use.