Table of contents

The 2022 2^nd International Conference on Energy, Power and Advanced Thermodynamic Systems (EPATS 2022) was successfully held in Nanjing, China in July 22-24, 2022 in the form of online conference. Energy, along with electricity, has become an indispensable part of our life, and they change the way we live. Under such a background, EPATS 2022 focused on the latest innovations and knowledge in energy and power engineering, stimulated new ideas and promoted collaborations in these areas.

We had the honor of inviting both Prof. Lim Yun Seng from Universiti Tunku Abdul Rahman, Malaysia and Prof. M.Shahidul Islam from Universiti Malaysia Sarawak, Malaysia to serve as our Conference Chairmen. 120 individuals and enterprises all over the world attended the conference. Divided into three parts, the conference agenda covered keynote speeches, oral presentations, and online Q&A discussion. Firstly, keynote speakers were each allocated 30-45 minutes to hold their speeches. Then in the oral presentations, the excellent papers selected were presented by their authors one by one.

During the conference, we were greatly honored to invite four sophisticated keynote speakers to address their speeches. Among them, Assoc. Prof. Sen Guo from North China Electric Power University delivered a thought-provoking speech on the topic: Comprehensive Performance Evaluation of Pumped Storage Power Station in China. In this research, a hybrid novel fuzzy multicriteria decision-making (MCDM) method combining the fuzzy best worst method (BWM) and fuzzy TOPSIS was proposed for the comprehensive performance evaluation of pumped storage power stations in China. Additionally, Prof. Zhenbin Zhang from Shandong University, China presented us his report: Cooperative-Predictive Control of Hybrid Microgrids. This report provided possible control solutions for further MG-based power grid, and presented the latest progress and contribution of his team in this field. Three research aspects were discussed, including predictive control of power converters in the primary layer, cooperative control of multiple distributed generators in the secondary layer as well as cooperative control between the AC and DC heterogeneous sub-grids. The wonderful and dramatic speeches of each keynote speaker had triggered heated discussion. Moreover, every participant praised this conference for disseminating useful and insightful knowledge.

We are glad to share with you that we received lots of submissions from the conference and we selected a bunch of high-quality papers and compiled them into the proceedings after rigorously reviewing them. These papers feature but are not limited to the following topics: Energy Storage Technology, Self-Healing of the Power Grid, Power Grid Coordination, Engineering Thermodynamics, etc. All the papers have been checked through rigorous review and processes to meet the requirements of publication.

On behalf of the conference organizing committee, we would like to express our heartfelt appreciation to all the keynote speakers, peer reviewers, and all the participants. Especially, we would like to acknowledge the Journal of Physics: Conference Series, for the efforts of all the colleagues in publishing this paper volume. We firmly believe that all the attendees have had fruitful discussions and gained valuable knowledge, and will enjoy the opportunity for future collaborations.

Committee of EPATS 2022

List of Committee member is available in this Pdf.

All papers published in this volume have been reviewed through processes administered by the Editors. Reviews were conducted by expert referees to the professional and scientific standards expected of a proceedings journal published by IOP Publishing Publishing.

• Type of peer review: Single Anonymous

• Conference submission management system: Morressier

• Number of submissions received: 81

• Number of submissions sent for review: 72

• Number of submissions accepted: 43

• Acceptance Rate (Submissions Accepted / Submissions Received × 100): 53.1

• Average number of reviews per paper: 2

• Total number of reviewers involved: 20

• Contact person for queries:

Name: Xuexia Ye

Email: xx.ye@keoaeic.org

Affiliation: AEIC Academic Exchange Information Centre

A new solar lithium bromide absorption - compression refrigeration cycle system was proposed for temperature and humidity independent control. MATLAB programming language is used to perform the thermal calculation of the new system, and the cycle characteristics of the typical day of the new system are analyzed. The influence of solar radiation intensity is analyzed. The results show that the new system can realize the cascade preparation and utilization of cooling capacity, and the optimal evaporation temperature makes the new system have higher performance.

In this paper, variables consisting of power, voltage and current in high penetration energy system are established to solve the matrix equation with energy storage access, taking the power supply of a 5-node system with 30% energy ratio wind power as an instance, the state of each node variable of the system was leveled by mean optimization method based on daily load curve, via calculating power flow, nodes voltage and current and evaluating corresponding output variable variances as evaluation index for optimization. The optimal effects of power flow, nodes voltage and current variables of the system before and after energy storage access were analyzed by simulation, and the variation and improvement of variance parameters were compared to verify the effectiveness and validation of the proposed method.

When pedestal looseness fault occurs, rotor system's vibration signals have non-stationary modulation characteristics. And traditional resonance demodulation method is difficult to determine the filter parameters. According to the fact, a pedestal looseness fault determination strategy of rotor system by using NA-MEMD (Noise-Assisted MEMD) is proposed. We use NA-MEMD to disassemble vibration signal into several stationary components. Envelope demodulation strategy is utilized to analyze each component. The vibration signal's fault message can be acquired through this way. The displayed strategy is utilized to analyze the simulated signal and pedestal looseness fault vibration signal. The comes about appear that the displayed strategy can successfully extricate vibration signal's fault characteristics of pedestal looseness fault in rotating machinery.

Accurate disk anomaly detection is of great significance for maintaining the safe and stable operation of the remote control system of natural gas pipelines. Most disk transfer algorithms use only a single-source domain model for offline transfer learning, resulting in lower classifier performance. This paper proposes a disk online anomaly detection algorithm combining transfer learning and incremental learning. A transfer learning algorithm based on data distribution similarity and dynamic index weighted ensemble is proposed. According to multiple source domain models and target domain model negative data in hyperspace, k neighbour data of each target domain negative data is extracted, and then different test criteria are adopted for each sub-model according to the number of target domain positive data, and index reweighting is performed according to the model detection capability. An incremental learning algorithm based on online automatic annotation is proposed. The data popped up by the sliding window is automatically marked at the current disk state, and the update period of the prediction model is dynamically adjusted according to the false detection rate and the missed detection rate. By setting three different experiments for comparison, the effectiveness and advanced nature of the method proposed in this paper are illustrated.

Comprehensive energy metering and electricity market-oriented transactions under the dual carbon goals put forward higher requirements on the accuracy of metering equipment clocks. The existing inventory of metering equipment has complex specifications, complex communication methods, and difficult management. Because of different production years, the old version of the metering equipment has poor clock retention capability and insufficient automatic time synchronization function. In order to solve the problems of clock accuracy and time management of metering equipment, a wide-area hierarchical collection and synchronization technology of clocks is designed, a technical framework for clock collection and synchronization of equipment at all levels of the system is constructed, and the normal state of system equipment is strengthened and maintained through the method of serial broadcast time calibration. Clock, designed a time-calibration protocol for object-oriented metering equipment. This technology has been applied to the clock management of on-site metering equipment, and the qualified rate of metering equipment clocks has reached more than 95%, which has improved the automation level of metering equipment clock management, the efficiency of time schooling, and the timely rate of time schooling.

With the transformation and upgrading of the energy structure, the installed capacity and power generation of new energy have continued to grow in recent years. Due to the randomness of new energy, the impact on the grid will increase with its large-scale grid connection. Therefore, in order to ensure the stability of the power grid, it is necessary to make a reasonable forecast of the new energy power. So far, there have been many authors using deep methods to perform new energy power forecasting. However, these methods usually assume the errors of the model across different time steps are independent, which is inaccurate because of the temporality of the series. In this paper, a method that combines neural networks with autocorrelation errors is proposed for new energy power forecasting. Through the ablation experiments in difference datasets, we verify the effectiveness of the methods.

Leakage failure of high-pressure superheater for waste heat boiler of gas-steam combined cycle unit was analyzed by metallographic analysis, scanning electron microscope, tensile property analysis and X-ray fluorescence spectrum. The results show that: The main cause of leakage failure of high-pressure superheater is under-deposit corrosion caused in long-term operation process. In view of the under-deposit corrosion causes of high-pressure superheater, preventive measures are put forward.

With the increase of population and the development of technology, energy use and pollution emissions continue to increase. While focusing on the development of new energy and renewable energy, electricity will continue to rise in future user energy supply ratios, and electrical alternative technology has become an important way for environmental protection and economic development. This paper takes the Tibetan region as an example to study the electrical alternative technology applicable to the Tibetan region. This paper selects the heat pump technology in the electric energy substitution technology, focuses on the analysis of the principle and unit structure of the heat pump technology, evaluates the performance of the heat pump with the performance coefficient and energy efficiency ratio, and analyses the performance of the heat pump through the T-S diagram and lgp-h diagram. It is concluded that with the improvement of the heating and cooling capacity of the single machine, its efficiency is higher and higher, and its energy-saving effect is also better.

A noise elimination algorithm of hydropower unit swing signals by using complete ensemble EMD (CEEMD) and permutation entropy is presented. The CEEMD is selected to decompose hydropower unit swing signals into several intrinsic mode functions (IMFs). Each IMF's permutation entropy is computed. These IMFs (whose permutation entropy is lower than preset threshold) are reconstructed to denoise these abnormal noises of hydropower unit swing signals. Wavelet transform and CEEMD are used to process noise of hydropower unit swing signals respectively. Noise reduction performance of two methods is compared. The results can be seen that the CEEMD method has better adaptability and denoising capacity. It's perfect for online applications for de-noising hydropower unit swing signals.

With the vigorous development of photovoltaic industry, the research on three-phase photovoltaic grid-connected inverter is deepening. For the problem, in this article, a combination of fuzzy control methods and traditional PI control is proposed to improve the adaptive capability of the system by constructing a composite fuzzy PI control pattern. At the same time, The LCL-type three-phase grid-connected inverter is simultaneously studied and the fuzzy PI control is validated through demonstration experiments. It is shown that the fuzzy PI control method is somewhat feasible in this system.

The large-scale connection of the renewable energy with random and fluctuating output of the grid has a serious impact on the safe and stable operation of the grid. Considering the high cost of energy storage and the fluctuation of load, in this study, an optimization approach for designing the distribution network's energy storage capacity is presented. This paper analyzes the uncertainty of new energy, and constructs a single distribution network energy storage station model based on the analysis results. In this paper, the typical daily total network loss is taken as the objective function for site selection and capacity planning. In this paper, particle swarm optimization algorithm is used to optimize the energy storage and capacity planning of distribution network. The experimental results show that this method can reduce the operating cost of distribution network and restrain the system load fluctuation. This method optimizes the economy and reliability of distribution network system.

the characteristics, advantages and disadvantages of four electric heat sources, as well as the characteristics, advantages and disadvantages of centralized electric heating and decentralized electric heating are compared and analyzed. Combined with the structure and working principle of the central heating electric boiler, the thermal efficiency and heat network loss of the electric boiler are analyzed, and the mathematical model of the total load of central heating is established. Finally, the model is used to budget the heating load.

The parabolic trough heat collection technology was mainly used in the field of high-temperature power generation, and there was less research on the application of medium temperature heat utilization. In view of the huge heat demand in the medium temperature range (120°C-240°C) in the industrial field, trough solar thermal technology for the medium temperature heat energy recovery have unique technical advantages and wide perspective applications. In this study, based on the meteorological resources of Ejina Banner (Inner Mongolia Autonomous Region) and the heat demand, we propose a design for small sized parabolic trough collector, aperture width is 2.55m, focal length is 0.721m, and rim angle is 83°. The optical efficiency of this collector is 77.05% calculated by Monte Carlo ray tracing (MCRT) method, and the heat flux intensity distribution of the collector is simulated by the Soltrace. Finally, the results can provide some support and technical references for the medium temperature application.

A high precision feedback control system with a given excitation current speed vector modulation and an integral saturated PI regulator is proposed for multi-scenario application of induction motor with wide speed and load in machine tool processing. Considering the characteristics of the variable range of voltage and current of the induction motor, the constraints of the excitation current of the motor and the slip frequency and other factors, the angular velocity vector of the induction motor, the given excitation current and the given speed variable are extracted as the adjusting variables of the feedback speed loop, and the transformation is carried out in combination with the relationship between the speed and the voltage of the modulation vector. The speed, torque, flux and three-phase stator current variables of the induction motor under the condition of constant torque, constant speed and torque and speed variables change were observed. By comparing the performance improvement of the proposed method with that of the conventional method, the effectiveness of the proposed method and the optimization characteristics of parameters were verified.

With the rapid development of the national economy, the system cabling rate continues to improve, the system capacitive current continues to increase, and the arc suppression coil grounding method is more and more widely used. Among them, the pre adjustable turn adjustable arc suppression coil accounts for the highest proportion. How to accurately, quickly and real-time measure and calculate the capacitive current of the system is the foundation to realize the automatic tracking and compensation of the arc suppression coil, It is also the key to reliably extinguish the arc and reduce the influence range of the fault when the single-phase grounding fault occurs in the system. Based on the analysis of the variation law of the capacitive current in the distribution network neutral grounding system through the arc suppression coil, this paper proposes a new method for measuring the capacitive current based on the resonance point curve fitting, which is suitable for the pre adjustable turn adjustable arc suppression coil grounding system, and verifies its reliability and accuracy through simulation.

To solve the problem of mixed integer nonlinear programming in dynamic reactive power optimization of distribution networks, a two-stage dynamic reactive power optimization model is used to reduce the size of the reactive power optimization calculation.The first stage is nonlinear planning, with the objective of minimizing the combined system network loss and node voltage offset. The second stage is a mixed-integer planning, with the objective of minimizing the incremental power system network loss on the basis of satisfying the constraints such as the number of equipment regulation throughout the day. In view of the fact that the conventional penalty function method to deal with the constraints will result in improper selection of penalty factors, an improved quantum state transfer algorithm with mixed filter technique is proposed. The algorithm adopts a two-population parallel search approach, and the individual adaptation degree and constraint violation degree are constituted as filter pairs as evaluation metrics to replace the penalty functions. Finally, the proposed algorithm, the traditional state transfer algorithm and Colony Algorithm are solved separately for the model using the IEEE 14 system as examples, and the correctness of the proposed model and algorithm is verified by comparing and analyzing the simulation results.

In the single-phase two-stage AC/DC converter system, the inherent power fluctuation of double frequency will lead to the double frequency fluctuation of DC bus voltage, which will affect the stable operation of the converter. In addition, this fluctuation will also raise the current stress of the double active bridge. This makes it more difficult to design DC bus capacitance parameters. In this paper, a design method of DC bus capacitors based on high ripple operation is proposed, and the theoretical limit of DC bus voltage ripple is analyzed. On the premise of considering stable operation and current stress of converter, the capacitance of DC bus is reduced to improve the power density of the system. The design of capacitance parameters has a theoretical basis to follow. Finally, the correctness and effectiveness of the method are verified by examples.

In order to solve the problem of distribution terminal layout in rural distribution automation planning, a scientific planning method for distribution automation terminal layout including microgrid is proposed. Firstly, the principle of distribution automation terminal configuration is analyzed, and the reliability evaluation method of distribution network considering distribution automation is studied. On this basis, an optimization model with the goal of minimizing the sum of the investment cost, operating cost, abandonment cost and power failure cost of the distribution terminal is established, and the genetic algorithm is used to solve the optimization model, so as to determine the distribution network Layout planning of automation terminals. The result of the improved IEEE RBTS Bus6-F4 example show that the method can obtain reasonable distribution automation terminal layout result.

The development of renewable energy sources such as solar and wind based on distributed generators are growing rapidly in the face of the global energy crisis. As a connection between distributed generation and the main grid, microgrids are also growing rapidly. However, due to the randomness and uncertainty of the output of the solar and wind power, as well as the bidirectional characteristic of current flow, the faults in microgrids are difficult to identify using the traditional fault detection methods. To address this problem, this paper proposes a machine learning-based fault identification method for microgrids. First, the modified K-means algorithm is implemented to cluster the voltage data. Then, FP-growth algorithm is using to extract the association rules. Third, the mini-batch gradient descent (MBGD) algorithm is using to train the fault identification model based on machine learning theory. To verify the validity of this method, a case study considering single-phase short-circuit fault and two-phase phase short-circuit fault is simulated. The method presented in this work is with a high accuracy according to the simulation results.

This paper proposes a distributed power supply consumption metering assessment index system and method for rural energy internet, which can be used in the dispatch and design departments of power companies. The method can solve the problems that exist in the existing distribution system, such as the lack of basis for siting and capacity determination and access of large-scale distributed power units, and the single and one-sided assessment index of distributed power consumption capacity. Firstly, analysing the characteristics of the new rural power grid, considering the impact of the uncertainty of distributed power supply output, organically combine the influencing factors of power quality, power supply reliability and operational safety and establish a multi-dimensional index evaluation system to measure the ability of distributed power sources to consume. Finally, the improved fuzzy estimation is used to determine the consumption capacity of the rural grid. The data of a rural grid operation is analysed by case study to accurately assess the consumption capacity of distributed power sources in the area.

With the rapid development of China's national economy, the length of transmission lines is increasing steadily, and the operating status of high-voltage transmission lines is directly related to the operational safety and efficiency of the entire power grid, but the sensors of transmission lines can only monitor one type of fault, and the fault analysis has limitations, which makes it impossible to comprehensively judge the operating status of transmission lines. This paper designs a transmission line online monitoring system based on multi-source data fusion, which adopts the improved Kalman filter algorithm. The data collected by the front-end system is fused, analyzed and shared in real time through the edge computing fusion terminal, so as to achieve a comprehensive judgment on the operation of transmission lines and improve the safe and stable operation level of transmission lines.

As the power market reform continues to deepen, microgrid plays an increasingly important role in promoting the local consumption of new energy and environmental protection. Therefore, it is of great significance to study the power market transaction with the participation of multiple microgrids.Blockchain technology is being used in many industries due to its decentralized and reliable data.This paper analyzes the advantages of the application of block chain in the micro-grid market, combines the advantages of block chain with the micro-grid market, and proposes a transaction architecture of the micro-grid market based on block chain technology.At the same time, this paper proposes a two-level optimization method.Finally, in this paper, through the simulation analysis method in promoting micro network market transactions, to improve the validity of the participants income by using the immune particle swarm optimization (PSO) algorithm to solve the model analysis.

The interruptible cost benefit of large industrial users is an important factor to decide whether to participate in interruptible load management, which has a direct impact on users' interruption and the choice of interruption strategy. Different industrial users have different production processes and electricity consumption characteristics. This paper first analyzes the production and power consumption characteristics of users, then analyzes the cost and benefit of large industrial users participating in interruptible load response, as the basis for judging whether users are willing to participate in interruptible load response. Finally, the case study can provide some guidance for enterprises to formulate the response strategy of interruptible load.

Fault location of the distribution network is an important direction in the construction of distribution automation. For the problem of slow convergence of intelligent optimization algorithms and easy to fall into local optimality, the multi-population particle swarm optimization algorithm is proposed. The algorithm is compared with single population particle swarm algorithm on IEEE69 node model, it is proved that the new algorithm can find fault location faster. Then the effectiveness of the algorithm in a variety of distribution network fault location scenarios is verified, including single fault location and multiple fault location, and the algorithm can also accurately locate when the input information is distorted which shows good fault tolerance.

As more and more distributed generation (DG) are added to the distribution network, the safe and reliable operation of the distribution network is challenged. Firstly, in order to quantify the benefits of energy storage improving distribution network reliability, a value model of energy storage improving distribution network reliability is established. Then, in order to calculate the load range that can be supplied by the energy storage when the failure occurs, a probability distribution model of the remaining energy storage when the failure occurs is established, and islands are divided according to the output of wind power and photovoltaic. Then, based on the sequential Monte Carlo simulation method and Latin hypercube sampling, the reliability of wind storage and distribution network is evaluated. Finally, the influence of different energy storage capacity on the reliability of distribution network is obtained through simulation calculation.

This paper presents a high-power medium-frequency hybrid full-bridge (FB) three-level (TL) DC-DC converter with crossing auxiliary capacitors. In this converter, two auxiliary capacitors are deployed between phases a and b, replacing the flying capacitor. The converter's three-level leg switches are with low voltage stress, while the two-level leg switches are with high voltage stress. The topology and modulation method, as well as the switching characteristics of the hybrid FBTL DC-DC converter with crossing auxiliary capacitors are described. The feasibility and performance of the above-mentioned converter is validated by a laboratory prototype. Based on the mechanism analysis and experiments, the zero-voltage switching (ZVS) and zero-switching loss (ZSL) of power switches, self-balance of the clamped capacitors voltages, and the voltage self-balance of the switches in the three-level leg can be achieved.

Photovoltaic power generation is the most significant way to utilize solar energy in the world today. Facing the severe fossil energy crisis and environmental crisis facing the world today, photovoltaic power generation has obvious advantages from the perspective of resource sustainability and environmental friendliness. The access of distributed photovoltaic power sources will change the power flow distribution in the distribution network. If the grid-connected load of photovoltaic access is light, the photovoltaic capacity is large. After the photovoltaic is connected, the distribution network will become a multi-source network, and the photovoltaic output will be large. During this period, the line is prone to reverse current flow, which increases the line voltage and affects the power quality of the distribution network. Thence, it is essential to consider adopting strategies to control the voltage of the distribution network to ensure the safe and steady operation of the distribution network.

The effect of indeterminacy of distributed generation should be fully considered in the planning of active distribution network. Based on the conventional load forecasting, the trusted output model of distributed generation connected to active distribution network is built. Thinking the influence of load demand side response on the forecasted load results, a distribution network load forecasting model considering the multiple synergistic interaction effect of source, load and storage is proposed. Based on the results of load forecasting, a double-deck multi-objective programming model of active distribution network is established. The upper deck function is the problem of power grid optimization planning, and the goal is to minimize the annual network comprehensive cost; The lower level programming model determines the active power output of manageable resources such as energy stored based on the typical daily system operation economy under the grid achieved by the upper part planning. Through the optimization solution, the distribution network planning scheme and the location and capacity scheme of energy storage under the active management mode are obtained. In result, we use an active distribution network in Shanghai to prove the scientificity and effectiveness of the proposed programming method

With the problem of worldwide energy and environment become more and more serious, the method that increasing power sources and the investment of substation construction is difficult to meet the rapidly growing power demand. From the theory of comprehensive resource strategic planning and the perspective of the whole society, consider the generalized power supply such as the photovoltaic power supply and interruptible load, establish double-deck programming model for areal energy optimal allocation in active distribution network. The upper planning takes the construction of generalized power supply and the minimizing the total cost of power generation and pollution control as target, improve installed volumn of various power supplies; The lower target is minimizing the net loss, and select address and determine capacitance for generalized power supply. In result, this paper use simplex method and improving PSO algorithm to calculate it. The result of a 33 bus system's simulation say that the method has the more obvious effect of energy conserving and emissions reducing than the traditional method.

Uneven energy distribution and "hotspot" phenomenon are bottlenecks restricting the development of the microwave heating industry. The formation of high-intensity electric field aggregation areas can be effectively repressed by optimizing the reaction cavity structures. With a box-type microwave reaction cavity as the study object and a built-in convex spherical as the induction device, the influences of the structural parameters of different devices on the microwave local field distribution were analytically explored through the simulation technology, and a "hotspot" early warning method was proposed. This study provides a reference for inhibiting the "hotspot" phenomenon on microwave fields and optimally designing microwave reactors.

Based on the need for energy-saving and consumption reduction in industrial applications, the effect of an internal concave structure on a heat exchanger tube with a right-angle trapezoidal cross-section and changing the flow direction on the heat transfer and flow characteristics in the tube was investigated. CFD techniques were used to study the effect of the inner concave structure with 15mm and 30mm center spacing and 1.88mm and 3.75mm radius of curvature on the heat transfer and flow characteristics of air under turbulent flow conditions in the range of Re13349 to 57847, and the heat transfer law was explored in terms of the combined heat transfer performance PEC and the coefficient of variation of the convective heat transfer coefficient and verified to be consistent with the field The effect of the variation of the synergy angle was confirmed. The results show that the PEC of the pipe is enhanced with the increase of the inner concave radius and the decrease of the inner concave center spacing.

With the goal of carbon neutralization put forward, new energy units have gradually become the main power supply, and its volatility has brought great challenges to the control and optimization of the system, especially the distribution network. In order to solve the reactive power problem caused by the high proportion of renewable energy connected to the distribution network, a source network load storage centralized optimal dispatching model considering reactive power optimization and multi energy collaborative interaction is proposed. The model aims at the optimal operation cost, minimum network loss and minimum carbon emission of the multi energy system, and considers reactive power compensation, energy storage regulation and energy conversion, so as to realize the safe and low-carbon economic dispatching of the electrical interconnection system. The switching capacity of the discrete reactive power compensation device is linearized, and the model is transformed into a mixed integer second-order cone programming problem for solution. The simulation results show that the proposed method can effectively compensate the reactive power required by the wind turbine parallel network, coordinate the energy interaction between electricity and gas, and improve the stability and flexibility of the distribution network after large-scale renewable energy access, According to the charging and discharging power and charge state, and the automatic adjustment of the gears of on load voltage regulating transformer and compensation capacitor bank, this paper shows that the system has safe and stable operation performance.

In this paper, the performance experiments and simulation studies on air conditioning heating under various fan frequencies were conducted using the air conditioning heating experimental device, and the key factors affecting air conditioning were studied. The experimental study concluded that with the gradual increase of fan frequency, the suction and discharge temperatures of the compressor, the outlet temperature of the heat exchanger, the mass flow of the air duct, and the thermal power consumption showed a gradually increasing trend. From the simulation study, it was found that by simulating the temperature field of the outlet temperature of the heat exchanger under different fan frequencies, and making a relative error with the outlet temperature of the experimental heat exchanger, the relative error is 2.5% at most; while simulating the velocity field of the experimental velocimetry tube flow rate and making a relative error with the experimental velocimetry tube flow rate, the maximum relative error was 1.8%. The research shows that the simulation calculation is highly consistent with the experimental results, which provides a direction and theoretical basis for the study of better air conditioning performance and optimal design.

The interfacial thermal conductivity has always been undetermined, and the discontinuity of temperature gradient at the interface will also cause problems in the study of the driving force of heat transfer. Based on Fourier's law, the generalized Fourier's law is proposed by assigning a subscript to the thermal conductivity, which can describe the unobstructed and blocked state of the heat transfer at the interface. By comparing the phenomena of the heat transfer and waterflow at the interface, it is deduced that the interfacial thermal conductivity always takes the smaller value among the thermal conductivities on both sides of the interface. Through adjusting the thermal conductivity, the temperature gradient is continuous at the interface, which guarantees the driving force of the interfacial heat transfer.

The optimization of structural parameters in ejector design is a problem of optimization of multivariate nonlinear unsteady flow field, in this paper, the numerical model of the ejector is established by using the computational fluid dynamics (CFD) method. The CFD model is used to study the influence law of the structural parameters of the mixing section, diffuser section and fluid inlet of the ejector, optimize the structure of the ejector, and find out the best scheme for the structural optimization design of the hydrogen ejector, so as to broaden the available load range of the ejector.

The construction of power grid infrastructure lags behind the growth rate of installed power capacity, which makes it difficult to deliver clean energy in some areas, and multiple clean energy sources seize power generation channels. Taking the power system in a certain area of Zhejiang Province as the research object, the day-ahead scheduling mechanism suitable for the joint optimization of multiple power sources under the limitation of transmission section is discussed, and an improved comprehensive power generation benefit evaluation system is established. Firstly, the coefficient matrix of objective function is defined, and a mixed linear integer programming model with variable objective function is established. Then, the transmission channel load rate and transmission power smoothness are defined as the social benefits of power generation in this area. Finally, the optimal cooperation strategy and unit output combination are determined by changing the objective function coefficient matrix. The analysis of an example shows that the comprehensive power generation benefit can be optimized by adopting the strategy of the big alliance cooperative game.

There are a large number of multi-dimensional different types sensors in DIoT (Distribution Internet of Things). Based on edge computing function of smart power DIoT terminals, local access and logical operations are realized. Data aggregation will reduce network traffic overhead and improve the real-time performance of edge computing. This paper proposes an asynchronous distributed aggregation layout construction algorithm based on hierarchical clustering. In this algorithm, all nodes are first aggregated according to the distance to construct a collection tree according to hierarchical clustering. And then the optimal number of groups is calculated according to the number of groups. Then the best aggregation node is selected according to the asynchronous distributed strategy. Simulation experiments show that the algorithm can quickly find a data aggregation method with minimal overhead, and improve the perception of power DIoT and edge computing efficiency.

Based on turbulence simulation and thermal radiation theory, the physical and mathematical model of electric heating film heating room is established, the appropriate grid form is selected to be meshed, reasonable boundary conditions are set, and the grid independence test is carried out and combing with the experimental test results, the correctness of the model is verified. The results show that the simulation results are consistent with the experimental results, and the maximum error is 13%, indicating that the simulation model is accurate enough. The simulation model provides ideas for related research in the field of electrothermal film heating.

Photovoltaic power station, as an emerging energy source, has been widely concerned by the industry at home and abroad, and has become a hot topic. It is also a task that cannot be ignored in the development of renewable energy at present. For photovoltaic power station, it has the advantages of simple and convenient power generation process, no need to use mechanical rotating parts, short construction cycle, simple operation and maintenance, unattended, convenient installation and expansion, and low maintenance cost, and has a good prospect of technology development. In order to promote the development of photovoltaic power station, this paper discusses the current basic situation of photovoltaic power station, and collects and analyzes its operation and maintenance data. The results show that the power generation during the operation and maintenance of the photovoltaic power station studied exceeds the theoretical level, confirming the feasibility of the photovoltaic power station operation and maintenance.

In this paper, the in-cylinder mixture formation process of a two-stroke spark-ignition direct-injection(SIDI) diesel engine is simulated and analyzed. The effects of the shape of the combustion chamber, the injection time and the initial temperature of the engine on the mixing process and the performance of the SIDI diesel engine are analyzed. The simulation results show that the offset combustor can obviously improve the fuel economy of the SIDI diesel engine. Under the premise of constant fuel injection quantity, there is an optimal fuel injection time to make the power performance and economy of the SIDI diesel engine optimal. Increasing the initial temperature is beneficial to the atomization of diesel oil and the formation of diesel mixture in cylinder. The results will guide the engineering design of SIDI diesel engine.

With the emergence and development of smart grid, digital meters have been widely used in substations, so the research on digital energy metering error has become a research hotspot. The purpose of this paper is to analyze the error of digital power measurement based on FPGA, mainly take the analog input fusion module and digital power meter in the digital power measurement system as the research object, and analyze the source of measurement error. An FPGA-based energy metering error detection platform is built to analyze the energy metering error when there are harmonics in the full energy metering method currently used by most digital energy meter manufacturers. The comparative analysis of numerical integration algorithms shows that the asymmetric distortion rates of the simulated waveforms are approximate. The results of measurement error analysis under harmonic conditions show that when the number of sampling points per cycle is 60, the power measurement errors of the 2nd to 4th harmonics are equivalent. The magnitude of the measurement error is still consistent with other low-order harmonics, and the simulation results are consistent with the theoretical analysis results.

Gasification kinetic parameters of coal char based on the random pore (RPM) model are obtained with CO₂ and H₂O using a high-pressure thermogravimetry analysis (TGA) under atmospheric pressure and 4.0 MPa pressure, considering the influence of internal diffusion and particle structure varying with carbon conversion. The Chemical Percolation Devolatilization (CPD) model is used to modify the actual volatile content. Through the coupling of the gasification kinetic reaction model, a comprehensive numerical simulation method of the entrained flow gasification process is established. This method is used to simulate the typical gasifier of HTL (a gasification technology of Changzheng Engineering Co.) in an industrial plant. The research shows that the intrinsic reaction parameters obtained by TGA under high pressure can give a more reasonable reaction state of coal char particles in the gasifier than that measured under atmospheric pressure, and the simulation results are in good agreement with the industrial data. In addition, HTL adopts a single top-fired burner and multi-channel swirling feed type. The particles are entrained and mixed with swirling oxygen, and the combustion reaction is completed quickly in the upper part of the gasifier. In contrast, the gasification reactions are relatively slow and mostly dominate in the recirculation zone and pipe flow zone, leading to high carbon conversion.

Most of the transmission poles and towers are built in the wild, and are often subjected to various loads such as wind, rain, ice and snow, especially the collapse of the tower caused by wind disasters. In order to study the response characteristics and disaster risk of towers under the wind field, this paper takes a 110kV transmission line as an example, and builds a "three towers and two lines" model based on ANSYS. Relevant specification parameters are calculated for the tower and conductor loads in this wind field, and the wind pressure time history is generated; based on the ANSYS transient analysis, the load wind pressure time history is used to analyze the dynamic response of the tower line, and the model is obtained in the static and dynamic wind field. Under the stress and displacement results, the response characteristics were analyzed. The research results can provide reference for tower design and line disaster prevention and mitigation.