Table of contents

It is our great honor to welcome you to the 2020 International Symposium on New Energy and Electrical Technology (ISNEET 2020) held on September 18-20, 2020 in Changsha, China. ISNEET 2020 welcomes researchers, engineers, scientists and industry professionals to an open forum where advances in the field of New Energy and Electrical Technology can be shared and examined. The conference is an ideal platform for keeping up with advances and changes to a consistently morphing field. Leading researchers and industry experts from around the globe will be presenting the latest studies through papers and oral presentations.

The meeting consists of two parts: oral presentations and speeches of keynote speakers. More than 50 participants attended the meeting. We were greatly honored to have invited Dr. Thanikaivelan Palanisamy from CSIR-Central Leather Research Institute, India to serve as our Conference Chairs.

In the keynote presentations part, we invited three professors as our keynote speakers. Our beloved Conference Chair, Dr. Thanikaivelan Palanisamy was also invited to present his talk Collagen Derived Advanced Materials for Energy and Environmental Applications. His research proposed new avenues for converting industrial bio-wastes into useful multifunctional advanced materials based on nanoscience approach are scalable and inexpensive thereby minimizing pollution and maximizing environmental sustainability. Dr. Ruomei Li, our second keynote speakers, from Tsinghua University, China presented her latest research: The Role of Human Nature in the Energy Revolution. Her speech had mainly analyzed the negative reactions from different sectors of the energy industry in facing the challenge of energy revolution, and Point out that those are the natural reflection of human nature. The last keynote speaker was Prof. Deng Feng, Changsha University of Science and Technology, China. Her speech topic is: Key technology of high precision real-time monitoring and control in the distribution network. This talk aimed to introduce the key technology of high precision real-time monitoring and control in the distribution network which has promoted significantly the scientific and technological progress in the field of distribution network safety monitoring, which is significant in reducing the hidden danger of personal equipment, reducing power outage, improving the utilization rate of equipment and improving the quality of people's production and life.

ISNEET 2020 is to bring together innovative academics and industrial experts in the field of New Energy and Electrical Technology to a common forum. Therefore, we compiled a lot of excellent papers featuring the latest advanced studies on the following topics: New energy resources, Electrical Systems, Energy Science and Energy Technology, Energy management and other related topics. All the papers have been through rigorous review and process to meet the requirements of International publication standard.

We are really grateful to the International/National advisory committee, keynote speakers, session chairs, organizing committee members, student volunteers and administrative assistance of the management section of University, including accounts section, digital media and publication house. Also, we are thankful to all the authors for contributing a large number of papers in the conference, because of which the conference became a story of success. It was the quality of their presentations and their passion to communicate with the other participants that really make this conference series a great success.

The Organizing Committee of ISNEET 2020

List of Committee member, Conference Chair, Organizing Committees, Technical Committees are available in the pdf.

All papers published in this volume of IOP Conference Series: Earth and Environmental Science have been peer 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.

• Type of peer review: Double-blind

• Conference submission management system: AI Scholar System

• Number of submissions received: 90

• Number of submissions sent for review: 80

• Number of submissions accepted: 53

• Acceptance Rate (Number of Submissions Accepted / Number of Submissions Received X 100): 58.9%

• Average number of reviews per paper: 2

• Total number of reviewers involved: 50

• Any additional info on review process:

• Step 1. Each of selected paper will be reviewed by two/three professional experts in the related subject area.

• Step 2. Review Reports received from the experts will be judged by one of the editors either Review Reports are logical or not?

• Step 3. If not logical, then editor can assign new reviewer or can also judge at his/her own.

• Step 4. If logical, then Review Reports will be sent to authors to modify the manuscript accordingly.

• Step 5. Authors will be required to revise their papers according to the points raised.

• Step 6. Revised version will then be evaluated by the editor for the incorporation of the points raised by the reviewers.

• Step 7. Then the editor will send the revised manuscript to the reviewers again for re-evaluation.

• Step 8. If the reviewers approve the revise version of the manuscript, then will be accepted for publication.

• Contact person for queries:

Xuexia Ye

publication@keoaeic.org

AEIC Academic Exchange Information Centre

With the continuous deepening of the construction of the State Grid, more and more power grid equipment such as substations need to be repaired and maintained in a timely manner, which makes the workload and difficulty of the power grid equipment operation and maintenance personnel more and more difficult. Electricity is a necessity for our daily life and enterprise production. In order to ensure the rapid and stable economic development, reliable power supply must be provided, and the normal operation of power equipment is the key to safe and stable power supply. Due to the rapid development of cities, various problems have begun to appear in some power grid plans, coupled with the upgrading of power grid equipment and the implementation of new power grid plans, making the operation and maintenance of power grid equipment more and more difficult, and more and more challenges high. Therefore, this article first analyzes the process of intelligent state maintenance of power grids, analyzes the key technologies of artificial intelligence in the operation and maintenance of power equipment, and analyzes the application of artificial intelligence technology in the operation and maintenance of power equipment.

In recent years, the construction of China's electricity market has achieved many results, and the market transaction volume and the proportion of clean energy consumption have increased significantly. With the expansion of the market size and the scope of the main player, the establishment of a clearing model for the electric energy market has been fully studied. This paper first introduces the current research status of foreign clearing models, and then according to the development trend of the electric energy market in the process of new electricity reformation, it summarizes and combs the electricity market clearing models under various market members and different scenarios by domestic scholars in recent years. Finally, it puts forward suggestions and prospects for the research of the future market clearing model, hoping to provide reference for future research.

As the core component of wind turbine energy conversion, the gearbox has been operating under variable frequency and variable load condition for a long time. The repair time is long after its fault, which leads to a large loss of power generation. This paper proposes a gearbox life prediction method. By collecting the design and manufacturing process parameters of gearbox, the gearbox virtual simulation model is established, the gearbox observable damage can be predicted accurately by inputting the actual operation load. According to the results, the maintenance and repair time of the gearbox can be arranged scientifically, which can effectively avoid the occurrence of serious faults, greatly reduce the gearbox replacement rate and unscheduled downtime, the economic benefits are obvious. After field application, the accuracy of this method can be 93.5%, which has a good prospect of application.

With the gradual deepening of power market reform, the top-level design of the market has been basically completed. According to the requirement of "Deepening Design Of National Unified Power Market", the ultimate goal of the power market in China is to establish a national unified operation mechanism of power market, so as to break down inter-provincial barriers, and finally realize the optimize configuration of power resources in a wider range. In this paper, based on the simplified model of national power grid, an optimal clearing model of the unified national power market with the province as the agent is established, and the validity of the proposed model based on practical scenario is verified.

Micro wind harvesting system with piezoelectric structure is an attractive method to power micro electric devices in outdoor field work. Interface circuit is one of the keys to improve the efficiency of harvested energy. A SECE interface circuit is design with microcontroller, which monitors the voltage and generates pulse signal. A simulation is performed in Multisim software to validate the proposed circuit. Results show that the maximum output power of classic interface circuit is 128.118μW at 110KΩ, and it increases to 390μW with proposed SECE interface circuit. It indicates that the efficiency of harvested energy is improved by 200%.

As a kind of special nonlinear load, pulse load (PL) has the characteristics of two typical nonlinear loads. Compared with the traditional rectifier load, the harmonic characteristics of the PL are more complicated. In this paper, the harmonic characteristics of the PL is investigated. By analysing the working mode of the PL, an equivalent circuit model and a switch function model of the PL are introduced. It is analysed that the PL will inject a large number of inter-harmonics and even sub-harmonics in addition to the integer harmonics to the power system, and the harmonics are symmetrically distributed. The experiments were conducted on diesel generator sets (DGS) with PL and public grids with PL. The results show that the established model and analysis method can accurately calculate the harmonic distribution of the system, moreover, the influence of PL mode on harmonic characteristics can be revealed.

Flexible bidding is an emerging electricity trading product in the Nordic spot market, which is different from hourly bidding and block bidding. It provides electricity generation enterprises and users with flexible and changeable electricity generation and consumption options and can reflect the electricity generation and demand-side behavior and habits of electricity generation and consumption, providing reference value for Chinese market participants to participate in the electricity market and demand-side response. This paper firstly introduces the two bidding models of hourly bidding and flexible block bidding; secondly, it introduces the market clearance model of flexible bidding; finally, it compares the differences between these two bidding approach.

Water and mud inrush are easy to occur in the process of karst tunnel driving, in order to reduce the risk of tunnel construction, TETSP is used in the prediction of karst cave, water gushing and mud gushing in a karst area of Longxing tunnel. The characteristics of TETSP geophone, detection principle and arrangement of observation system are introduced. The signal-to-noise ratio of TETSP data under blasting and hammering is compared. The corresponding unfavorable geology abnormal law of TETSP is summarized. Several conclusions are drawn as follow. Firstly, the TETSP geophone with direct coupling method has high installation efficiency and can obtain the original waveform with high signal-to-noise ratio. Secondly, the seismic reflection data collected by blasting is higher quality than that by hammering excitation. Thirdly, the abnormal law of the corresponding TETSP of large-scale karst cave and dissolution fracture zone present as that the P-wave velocity and S-wave velocity are low but Poisson's ratio is high. The prediction results of TETSP are consistent with the actual excavation of the tunnel which provide an important reference for the safe construction of the tunnel.

Under the new reform requirements, the transmission and distribution price pricing model changes, the sales side is liberalized and competition is introduced, the incremental power distribution business investment is liberalized, and the company's permitted income is approved on the basis of effective assets. In this paper, the combination weight TOPSIS theory is used to diagnose and evaluate the physical assets of power grid companies, and the accuracy of the model is verified through analysis, and the system's asset status diagnostic analysis and evaluation research is carried out, and the optimization strategy and evaluation calculation are scientifically proposed to provide a research and analysis basis.

The elastic coefficient K, a factor affecting the life of capacitive RF-MEMS switch, is selected as the research object. First, we use differential evolution based quantum particle swarm optimization (DE-QPSO) to obtain sparse functions of multiple kernel relevance vector machine (MKRVM), and use the MKRVM algorithm to predict the lifetime of such switches. Then the experimental results show that the method can obtain the health index HI of 3.1043e+06 s, the 3.0657e+06 s. closest to the original data in 0.21 s. At the same time, the conclusion of the longest switching life is obtained when the elastic coefficient is in the range of 4-16 N/m.

Pumped storage power stations have excellent characteristics such as fast start and stop speed, rapid load increase and decrease speed, and low forced outage rate, which can effectively improve the safety and economy of the power grid. This paper proposes a method for economic analysis of pumped storage based on a multi-scenario random unit combination model. In this paper, we build a scenario tree model based on the statistical characteristics of wind power and load forecast errors, and use a scenario modeling method based on associated nodes to build a stochastic unit combination model; Based on the results of system analysis, the economic efficiency of pumped storage power station is calculated, and the feasibility of the model is verified by example analysis, and the difference between calculation results of different models is also analyzed.

The design and manufacture of magnetic components such as inductors need to estimate theoretical parameters based on the working characteristics of circuit on the one hand, and select the magnetic core and winding method by experience to determine the manufacturing plan. The parameters and performance of magnetic components obtained by different winding methods are usually different, so the design results have certain uncertainty. In order to better obtain system indicators, a design method for the design of the tapped inductor of large step-up ratio DC/DC converter is proposed to calculate the key parameters such as the turn ratio and inductance of the tapped inductor. The optimized winding scheme method of the tapped inductor is proposed by combining electromagnetic field simulation and circuit simulation. The simulation results show that the theoretical parameters obtained under the proposed method are correct, and multiple performance indicators of the tapped inductance corresponding to the converter circuit under different winding modes can be obtained, which is convenient for the designer to find the best appropriate production plan according to actual needs.

Caused by the fluctuation of weather conditions, the transmission line ampacity varies with time. For power system operators, the accurate forecast results of overhead transmission lines ampacity are very important and helpful in making planning and control decisions. To assist the system operators in making better use of the transfer capability of transmission lines, it is urgent to improve the ampacity forecast results. In this paper, a novel method based on the extreme learning machine (ELM) is proposed to predict the ampacity. Taking the historical weather and ampacity data as the input data, an ELM-based method can predict the ampacity rapidly and accurately. Numerical simulations based on the recorded actual weather data around a transmission line validate the efficiency of the ELM-based ampacity forecast method.

Micro electric devices have been widely applied in outdoor field work, but the battery power limits its performance. Piezoelectric energy harvesting from wind-induced vibration is an attractive power solution for the micro electric devices in field work. Its output characteristics of proposed system is analysed under different wind speed and direction. Experimental results show that the proposed system can harvest more energy if the incoming flow is parallel to the piezoelectric plate. Its output voltage increases from 2.5V to 10.3V when the wind speed ranges from 9m/s to 21m/s. The output voltage can achieve 8.5V, if the flow direction is vertical to the piezoelectric plate. But the proposed harvesting system outputs very small voltage in case the flow direction from the top. These results show that the piezoelectric energy harvesting system can collect the wind energy from multi-direction, and have potential application to power the micro electric devices.

Aiming at the problem that the wind vane of wind turbines has a deviation to the wind, which damages the power generation efficiency of the unit, a filtering method of abnormal working conditions based on DENCLUE density clustering is proposed, which mainly included two stages of working condition screening and calculation of the angle of the wind deviation. Firstly, the density clustering algorithm based on DENCLUE is used to filter the working conditions of the data and to filter out the working condition data of abnormal power generation. Then, the data is further processed, including data smoothing and wind speed binning. Furthermore, according to the relationship between the output power of the unit and the yaw angle of the wind deviation, a regression model is established to obtain the wind deviation angle of the unit. Finally, the method is verified through the actual operation of SCADA data. The results show that after filtering the working conditions, more stable output can be obtained and the performance of the unit can be obviously improved.

A three-dimensional geometric model of anode contact of vacuum circuit breaker is established. Considering the influence of electrode rotation on vacuum arc and anode thermal process, a physical model of phase transformation process is established for the melting and evaporation of anode surface. The solid-liquid mixing area is treated by the description method of porous media, and the numerical simulation of anode thermal process is carried out. The conclusion is that with the increase of time, the anode surface temperature increases, molten pool development, molten pool depth deepening, in addition, with the increase of electrode speed, the highest temperature on the surface of the contact and the size of the molten pool were reduced, the temperature distribution more uniform. It provides theoretical basis for evaluating the breaking capacity of vacuum circuit breaker.

Insulators are important power grid equipment and key components to ensure electrical insulation performance. Porcelain insulators with reduced insulation performance are generally low or zero, and are broken down under lightning overvoltage or even normal operating voltage. The thermal effect generated by the strong power frequency fault current flowing through the porcelain insulator will often cause deterioration of the porcelain insulator. The iron cap exploded, causing serious accidents such as stringing of insulators and grounding of wires. If there are continuous multiple pieces of zero-value insulators in the insulator string, the voltage of the insulators around the zero-value insulators will increase compared to normal conditions, and the normal insulators farther from the zero-value insulators will be less affected. If there are multiple consecutive zero-value insulators at different positions in the insulator string, if the number of zero-value insulators in the insulator string is large enough, and the distribution positions are more diffuse, the voltage of the entire string of insulators in the insulator string will be biased as a whole high.

In a strong electromagnetic environment, there is a great demand for the parameters needed to monitor the operation of lines or substation equipment, and the reliability of the monitoring device is a problem that needs to be researched. According to the need for heat dissipation and assembly of the cavity of the wire penetration monitoring device, for the high-voltage and high-current wire access point and the hole structure inside the device, this paper establishes a cavity model with a ring-shaped gap through a wire and derives the analytical formula of the electromagnetic field in the cavity, then the influence of plane wave pitching angle, the structure parameters of the conductor and the position of the wire on the internal resonance characteristic transformation of the through wire cavity are analyzed. The simulation analysis results can be used for the structure and shielding design of the wire penetration monitoring device under the electromagnetic environment of transmission lines and substations.

In the process of power transmission, power quality disturbance is caused by the phenomenon of "excitation inrush current" and "leakage resistance" of the core equipment AT in the power supply system. Harmonic signals contain higher harmonics. In this paper, the power supply system under AT mode is modeled, and a damping trapezoidal algorithm is proposed to suppress the numerical oscillations caused by the coupling between AT windings. A new orthogonal matching pursuit algorithm for multi-spectral interpolation correction is proposed. (OMP-MIC), reconstructing the occurrence of higher harmonic signals, improving reconstruction efficiency and accurately recovering the original signal; finally, verifying the validity of the model and the superiority of the reconstruction algorithm through simulation.

Voltage sag, as a prominent problem among many power quality problems, has always plagued power grids and users. To reduce the loss caused by the voltage sag and provide a basis for the prevention of the voltage sag, it is important to accurately and efficiently predict the risk of the voltage sag. This paper analyses the related factors of voltage sag risk from multi-directional and multi-dimensional, obtains the data of the influence factors of voltage sag risk in various information systems of the power grid, constructs voltage sag multi-source data, and uses Elman neural network to construct voltage sag risk prediction model. Through the training and learning of multi-source data, the model realizes the voltage sag risk assessment of each node in the power grid. Finally, the feasibility and validity of voltage sag risk prediction model are verified by case study of historical monitoring data in Fujian Province, which provides a method for voltage sag risk prediction.

As there is no special engineering software for simulating voltage sags caused by grid faults, this paper compares the differences between the existing BPA and PSCAD simulation software in the voltage sag simulation process, and analyzes the applicability. First, analyze the similarities and differences between the transient and steady-state characteristics of the basic devices in BPA and PSCAD, as well as the parameter conversion method; Secondly, based on actual grid data, two sets of software are used to model and simulate the voltage sag caused by grid faults. Finally, through the comparison and analysis of simulation results, the different applicability of the two sets of simulation software in voltage sag simulation is summarized.

The temperature rise caused by three-phase short current at stator side of doubly fed induction generator (DFIG) may damage DFIG and its adjacent electrical equipment. By using the step-by-step integration, the thermal effect may be quantified, but the contribution of periodic component and aperiodic component of thermal effect cannot be distinguished, and the amount of calculation is large. In this paper, the steady-state component of rotor flux is considered to reduce the error of analytical expression of short current. The components of short current are decomposed and the square of the short current is integrated. The calculation method of equivalent duration of aperiodic component of thermal effect is proposed, and the effect of equivalent duration on different crowbar resistance and stator voltage drop ratio is quantified. The simulation results are provided to validate the accuracy of the proposed models.

In order to prevent power electronic devices from causing harmonic pollution to the power grid, PFC technology is widely used between power electronic devices and the power grid. Therefore, the improvement of system power factor and robust performance has become a research focus today. This paper is aimed at dual Boost bridgeless PFC (power factor correction) converters, establishes a mathematical model in virtual dq mode, and a new nonlinear control strategy based on Lyapunov stability is proposed. The MATLAB simulation results show that the input current can better track the input voltage in the steady state, and when the load or output voltage changes, the system can quickly enter stability, and the system has strong anti-disturbance ability.

Based on the characteristics and design concept of the IR46 intelligent IoT electric energy meter (hereinafter referred to as the IoT electric energy meter), from the perspective of verifying its design, practicability, and quality, a hardware detection device solution that satisfies the IoT electric energy meter is proposed. It satisfies its multi-core modular hardware detection requirements, can effectively guarantee the network access detection of IoT electric energy meters, improve detection efficiency, and reduce the difficulty of development of electric energy meter manufacturers. A reasonable hardware detection device solution is provided for the implementation of IR46 electric energy meters in China.

In this paper, dual tree complex wavelet transform (DT-CWT) is used to decompose UHF partial discharge (PD) signal in multi-scale. The optimal decomposition level of complex wavelet is solved. The wavelet energy features of real part and imaginary part of UHF-PD signal under the optimal decomposition scale are extracted. Fisher linear discriminant method is used to select the features of energy features and to identify the PD types. The results show that the optimized real part and imaginary part high frequency wavelet energy features can effectively identify four kinds of typical insulation defects, and the recognition rate can reach to 92.5%. Meanwhile, the optimal complex wavelet energy (OCWEF) feature has better sensitivity and recognition effect in PD type identification.

The traditional phase locked loop (PLL) is realized by analog circuit. Compared with PLL realized by traditional analog circuit, digital phase locked loop (DPLL) has the advantages of high precision, not affected by temperature and voltage, adjustable loop bandwidth and center frequency, and easy to construct high-order PLL. With the rapid development of communication technology and integrated circuit technology, DPLL will be more widely used. In this paper, the PLL macroblock is used to design and realize the functions of frequency division, frequency doubling and phase locking in Quartus II development environment. The validity of the design and application of the DPLL is verified by practical verification.

Through the introduction of a partial discharge fault event at the end of 110kV cable, through on-site inspection and on-site acoustic-electrical test, it is determined that the partial discharge at the end of 110kV cable is abnormal, and there are defects of suspension discharge or insulation discharge; Based on the phase analysis of high-frequency current signal and UHF time series data, the fault location analysis is carried out. The analysis shows that the cable A and B have the same insulation discharge defects. According to the reason of the defect, it is suggested to carry out the overhaul of the air chamber of the interval cable immediately to prevent the cable accident caused by the defective operation. It also proposes to standardize the cable terminal installation process and strengthen the cable quality supervision, focusing on and checking the equipment of the same manufacturer and model to prevent similar defects. This study can be used to guide the operation and maintenance of partial discharge in cable terminal.

Aiming at the current situation of serious economic losses caused by lightning shielding on the collection lines of wind farms in mountainous areas. First, this paper uses the horizontal section location map of the collection line to extract the terrain parameters, Then use the catenary equation to determine the spatial position of the conductor and ground of any section of the collector line along the pitch direction, and obtain the height of the conductor and the ground to the ground. Finally, complete the modeling calculation analysis of the three-dimensional electrical geometry model (EGM) of the entire collection line. The calculation results show that, when the thunderstorm day, the arrangement of the collection line and the structure of the tower are the same, the SFFOR of the collection line of the wind farm in mountainous terrain is 0.487 times/100 km/year, and the plain terrain is 0.167 times/100 km/year, that is, mountainous area is 2.9 times of plain terrain; It is recommended to use double lightning protection poles with small protection angles on the collection lines of wind farms in mountainous areas, or install lightning arresters for poles that are prone to flashover to meet the design requirements of line lightning protection.

With the advancement of computer and sensor technology, visualization research has been more and more widely used in the industrial field, especially for arc plasma research of high energy fields. During the electrical breaking process, the DC arc energy distribution directly affects the working performance of the switchgear. A single voltage and current monitoring method is difficult to characterize the complex energy evolution process of the arc. Therefore, the visualization of the arc energy distribution is particularly important. In this paper, the arc energy distribution of the arc combustion process is visualized as the main research content. The arc characteristic detection platform is built, and the voltage, current, contact displacement value and arc image between the contacts are synchronously collected. According to the spectral characteristics of the color CCD image sensor, the colorimetric temperature measurement formula with calibration coefficient is derived to establish the relationship between the pixel and the arc temperature. The acquired arc image is processed by matlab image processing technology to visualize the two-dimensional energy distribution characteristics of the arc in the horizontal projection direction during the breaking process.

In recent years, with the development of economy and the rapid growth of electricity consumption, the number and length of medium and high voltage cable lines have increased rapidly. As an important part of the power transmission and distribution network, to ensure the safe and reliable operation of cable lines and reduce unplanned power outages. Based on the field test and analysis of the abnormal ground current of the 110kV Luoyong line, it is found that the cross interconnection system has many defects such as phase sequence error and identification plate indication error. It is recommended that the cable cross interconnection system carry out a segmented insulation resistance test to exclude cables. Hidden dangers such as damage to the protective layer and damage to the protective layer.

Compared to AC system, DC power system is more likely to be damaged by short current, because in DC system the fault current increases faster and doesn't have zero crossing point. The DC current limiter (FCL) can limit the rise of the current, thus it is efficient to use FCL to improve the reliability of the power system. Based on the previous research, we proposed an improved topology, established its mathematical model and analyzed its working processes. Besides, parameter design methods of solid-state DC current limiter are proposed by combining modeling and image analysis. And the control strategy of DC transformer short circuit fault crossing and recovery is put forward. Simulation and experiment results proved the effectiveness of topology and control strategy we proposed.

In recent years, the ablation damage of overhead insulated conductor on the top of insulators has posed a threat to the safe and stable operation of distribution network. In this paper, a three-dimensional model including insulator, binding wire and conductor is established in the finite element simulation. Then analyse the influence of the existence of binding wire and the diameter of binding wire on the electric field distribution of conductor. Providing a theoretical basis for the cause and prevention of the ablation damage of conductor insulation layer. The simulation results are as follows: When binding wire exists, electric field distortion will occur in the insulation layer and surface air around the conductor. The maximum electric field intensity of the surface air around conductor reaches 15.5kV/cm, which is about 690% higher than that without a binding wire. The maximum electric field intensity of the insulation layer reaches 4.3kV/cm, which is 980% higher than that without binding wire. In addition, as the diameter of the binding wire increases, the maximum electric field intensity in the insulating layer decreases and the maximum electric field intensity in the air on the surface around the conductor has small change.

The economic development of East China is in a leading position in China, the demand for electricity is growing rapidly, and the load peak-to-valley ratio continues to increase. During the 14th five-year Plan period, as the amount of new energy access continues to increase, the pressure on peak shaving in the region will continue to rise. Based on peak-regulating demand, this paper calculates the investment economic level of pumped storage power stations in east China under different utilization hours and different capacity electricity prices, so as to provide reference for investment and cost control of pumped storage power stations at various stages, and puts forward suggestions on the coordinated development of pumped storage power stations and new energy installations.

"Distributed generation and Energy storage technology" has become a widely promoted operation mode to ensure reliable power supply when the distributed generation connected to the grid. In order to realize the unified regulation of energy storage, this paper summarizes the auxiliary operation function, market profit model and market operation mechanism of energy storage from three sides of generation, grid and users. The Distributed Energy Storage Operation Platform constructed through the strategy of "Hierarchical and Partitioned". The good interaction between energy storage users and power grid realized through the comprehensive services of the platform. Several types of user categories and incentive mechanism under the interaction mode of grid and users sides summarized. Finally, the operation mechanism of distributed energy storage market summarized and prospected.

Chile was one of the first countries in the world to successfully reform its electricity market. Limited by the dilemma of energy dependence on imports, Chile's electricity price fluctuates greatly. Therefore, in recent years, Chile has been committed to the transformation of the new energy structure and introduced a series of policies to promote its energy development. This paper analyzes the current situation, the reform process, and the operation mechanism of the electricity market in Chile, Focused on the characteristic mechanisms and policies in Chile's energy transition. Finally, combined with the current situation of China's electricity market, draw lessons from Chile's electricity market construction highlights and put forward relevant thinking and suggestions.

In recent years, the planning and operation of integrated energy system has received extensive attention. The traditional two-stage nonlinear model of planning and operation has problems such as inability to reach the global optimum and low solution efficiency. By linearizing the nonlinear constraints, this paper introduces a coordinated optimization model of planning and operation of integrated energy system based on mixed integer programming, which takes the minimum annual cost as the objective function and considers the coupling characteristics of electrical, thermal, and cooling load. The model achieves the optimal capacity configuration and operating scheme at the same time. Results of the testing data verify the effectiveness of the model.

With the vigorous development of wind power generation worldwide, the problem of stress concentration at the position of the main shaft shoulder of the wind turbine has become increasingly prominent. Therefore, a finite element model was established for the main shaft of a wind turbine, and the stress field of the main shaft of the wind turbine under the limit load condition was simulated and calculated, and the influence of the position of the shoulder on the flange side on the stress concentration under different radii of curvature was analyzed. It provides important guidance for the manufacture and inspection of the main shaft of the wind turbine.

In order to harvest the acoustic energy in the environment, an electromagnetic acoutic energy harvest system is proposed based on Helmholtz resonator, coil, permanent magnet and interface circuit. When the sound wave is injected into the resonator, it causes the upper surface permanent magnet to vibrate and outputs electrical energy from the coil. The resonant frequency of the resonator is simulated and analysed by finite element method, the interface circuit is simulated and analysed, the acousto-electric conversion principle is analysed theoretically. The output characteristics of the system under different frequencies and sound pressure levels are studied by experiments, and the output characteristics of the system after using the interface circuit are studied. The experimental results show that the system can harvest the acoustic energy of different frequencies, and the power generation effect is better when the acoustic frequency is near 98Hz and 140Hz, which is close to the first two resonant frequencies of the system. The output voltage and power of the system increase with the increase of the sound pressure level. When the sound pressure level is lower than 105dB, the output voltage and power of the system under the acoustic frequency of 95Hz is higher, and when the sound pressure level is greater than 105dB, the output voltage and power of 140Hz acoustic frequency is higher. After using the interface circuit, the maximum open-circuit voltage is 13.65V when the sound pressure level is 110dB and the frequency is 98Hz, and the maximum output power of the system can reach 0.625mW when the sound pressure level is 110dB and the frequency is 140Hz.

The traditional finite-control-set model predictive control (FCS-MPC) of three-phase active power filter (APF) has the problems of low compensation precision and long control delay. In order to address this problem, this paper proposes a multistep prediction compensation control method for the FCS-MPC of APF, it does not require modulation of PWM link. By utilizing the discrete mathematic model of three-phase parallel APF and keeping the advantages of traditional FCS-MPC, the prediction model is established based on the structural model of traditional FCS-MPC, the predictive controller is designed for predictive control of DC-side voltage. AC-side current and fixed switching frequency, and simulation study is also conducted. The simulation results show that the multi-step predictive control method can effectively track and compensate harmonic, reduce the harmonic component of power grid, and increase the compensation precision of parallel APF.

Ni-Cd battery pack is an important part of spacecraft, and its performance is easily affected by the changing magnetic field. In order to grasp the anti-magnetic pollution ability of the battery pack, this paper conducted a charge and demagnetization test study on the battery pack in a magnetic field environment simulation site by adjusting the intensity, frequency, waveform and other magnetic parameters to investigate the charging and demagnetizing effect of the battery pack. The results show that the Ni-Cd battery pack has weak resistance to magnetic pollution and is easily magnetized. In addition, when the magnetic strength is 4.5 mT and the frequency is 1.5 Hz, the demagnetization in three directions of the Ni-Cd battery pack can be well accomplished. This study provides a reference for the use of Ni-Cd battery packs in the magnetic environment and the removal of magnetic pollution effects.

The ocean moving target is covered by the vast ocean, and it is highly concealed. In order to effectively detect the moving target in the ocean, based on the theory of magnetic flux induction, the characteristics of the detected target are analysed, the equivalent magnetic model of the target is established, and the rectangular induction coil structure is designed. The coil structure was optimized by studying the effects of coil size parameters and moving target motion parameters on induced electromotive force. Finally, through field trials, using induction coils to collect and analyse the signals of wooden boats, speedboats and kayaks, the feasibility of the detection technology was verified, which provided a new way for the detection of shallow sea moving targets.

In order to provide more accurate and consistent reference current for power system under different loads, the constant current performance of the high-current power amplifier is studied. This paper presents a circuit topology suitable for high-current power amplifier circuits, and analyses the key factors that affect its constant current characteristics. It is found that resistance matching plays a decisive role in the constant current characteristics. Through quantitative analysis and verification, the boundary conditions of the output resistance of the high-current power amplifier under the specified resistance accuracy are also found. Then based on Monte Carlo analysis and worst-case analysis, the previous theoretical derivation afterwards is conducted. Finally, an effective method of resistance matching is brought forward, which is authenticated in the contrast test later.

Power transformer is the core equipment of the power system. Its operation status directly affects the security and reliability of the whole system. Therefore, it is of great significance to evaluate its status timely and accurately. Acoustic imaging technology is first used in medical, communication and other fields, which can effectively sense abnormal sound and locate it accurately, which greatly improves the work efficiency. This paper introduces the application of acoustic imaging technology in live detection of power transformer. The result shows that the combination of acoustic imaging technology and traditional live detection technology can improve the working efficiency of live detection and the accuracy of transformer condition evaluation, which is conducive to maintaining the safe and reliable operation of power grid.

With the rapid development of high-speed rail technology in China, the traction transformers of various types have been used more and more extensively. The differential protection of traction transformers has different differential conversion modes ^[1-2] which are different in their sensitivities. In this paper, taking the YNV traction transformer as an example, by comparing the sensitivities of two different common differential conversion modes and through analysis, it shows that the sensitivities of differential protection are slightly different. The sensitivities of differential protections based on different principles depend on the retention degree of differential current to the positive sequence, negative sequence and zero sequence components in the internal fault current. The sensitivity of phase current minus zero sequence differential is the highest when single-phase grounded, which completely retains all the sequence components in the internal fault current. The sensitivity of interphase differential protection is the highest when interphase fault occurs. The widely used phase current differential and phase current minus zero sequence differential do not reflect the zero-sequence component of internal fault current, which provides the basis for field fault analysis and setting.

In order to identify functional safety property of battery management system, safety integrity level of BMS research is performed by average frequency of a dangerous failure of the safety function. The result shows that: currently, functional safety has been research at home and abroad, through evaluation system of road vehicle and electrical, electronic, programmable electronic safety-related systems. So, safety integrity level could be analyzed quantitatively by a functional relation, which is established among tolerable hazard frequency, demand rate on safety-related protection system, dangerous failure of average frequency and safety integrity level. Based on tolerable hazard frequency and the demand rate on safety-related protection system, safety integrity level of a BMS is evaluated as level II.

Energy storage has the advantages of fast response and accurate power tracking when participates in frequency modulation. By dividing the Area Control Error (ACE) and battery's State of Charge (SOC) into different regions, combining them with four different emergency frequency modulation states, this paper proposes a partition coordinated control strategy for energy storage to participate in frequency modulation. According to the regional interconnected system, the model of energy storage participating in power grid frequency modulation is built in MATLAB/Simulink. Based on the conventional control and the partition coordinated control, the frequency waveform analyzed. The results show that the energy storage participating in frequency modulation can effectively shorten the regulation time and reduce the frequency fluctuation. The fuzzy control used to optimize the partition coordinated control strategy to make the whole link have better frequency modulation ability.

The energy storage technology is one of the advanced technologies to solve the problems of modern power system, and also an indispensable key technology for the construction of smart city power grid. A mechanical elastic energy storage (MEES) technology is proposed in this context. As a new physical energy storage technology, the MEES is still in the principle verification stage compared with other physical energy storage technologies researched and developed for many years. In this paper, the MEES system is introduced from the composition, the principle of energy storage/power generation, and the key technical parameters of energy storage. The advantages and disadvantages of MEES system are pointed out, and the future development direction of the MEES technology is clear.

In order to harvest low frequency acoustic energy, a novel hybrid piezoelectric-electromagnetic micro-power generator was developed with Helmholtz resonator, piezoelectric patch, coil and permanent magnet. When the sound waves enter Helmholtz resonator, piezoelectric patch and coil will be vibrated then the electric energy are generated from them. With Multisim software, the circuit of proposed micro-power generator was simulated and its output performance was analysed. Results show that there is always an optimal resistance to maximize the output power of the novel hybrid piezoelectric-electromagnetic micro-power generator. Especially when the sound waves at 82Hz, the output power of proposed hybrid generator can more than the sum of independent piezoelectric and electromagnetic micro-generator. It indicates the power generation efficiency is significant significantly improved by the proposed hybrid method.

Weathering steel material has good corrosion resistance and mechanical properties. Compared with galvanized steel tower, weathering steel has longer operation life and lower operation and maintenance cost. With the pilot operation of weather resistant angle steel tower on the transmission line, its electrical performance has been widely concerned. The impact impedance of the tower is an important parameter to evaluate the lightning strike back performance of the tower. The rust layer formed on the surface of the weathering steel material will cause large lap resistance, which may increase the lightning strike back risk of the tower. In this paper, the impulse impedance test of a 220kV weathering angle steel tower in Fuyang, Anhui Province of China is carried out, and the circuit calculation of the test results is carried out to verify the rationality of the test data. The results show that: the zero frequency resistance of 220kV weathering angle steel tower is 1.027Ω, and the low frequency inductance is 311.94μH. The impact impedance results of the tower not only depend on the size, material and model of the tower, but also related to the impact waveform; the test results are in good agreement with the circuit simulation results.

To improve the micro-positioning accuracy of piezoelectric bimorph actuators, a driving power was designed with filter compensator. Amplifier modular was designed with high-voltage operational amplifier, and filter compensator modular is responsible for charge signal. Simulation results show that the output of filter compensator modular is proportional to the electric charge on the actuator. Experimental results indicate that the maximum error is 10μm without filter compensator modular, and reduced to 5μm with proposed driving power.

In this paper, the method of molecular dynamics simulation is used to study the Cu-Ar nanofluid. It is found that when Cu nanoparticles of different volume fractions are added to liquid Ar, the thermal conductivity of the nanofluid can increase by 32.1%; adding different sizes of Cu nanoparticles. In the case of particles, the thermal conductivity of nanofluids can increase by 15.2%. On this basis, the strengthening mechanism of the thermal conductivity of the nanofluid was analyzed from a microscopic point of view, and it was found that the microstructure of the base fluid has changed after adding nanoparticles. The degree of change of the microstructure of the base fluid is greatly affected by the size of the nanoparticles. The closer to the nanoparticle base fluid, the more significant the microstructure changes. The thickness of the adsorption layer was calculated by dividing the surface of the nanoparticle and tracking the movement trajectory of Ar atoms in these areas and counting changes in the number of argon atoms. It was found that the adsorption layer was a key factor leading to the improvement of the thermal conductivity of nanofluids.

GIS is the significant equipment in UHV network. However, after the UHV GIS busbar switch is opened, there will be a higher residual voltage on the GIS busbar, which causes the basin insulator flashover during the commissioning of the substation, which seriously affects the insulation and safety performance of the power system. It is very necessary to study the residual voltage on the GIS busbar. Therefore, we established a set of the GIS busbar residual voltage measurement system. Based on electric field measurement method, the GIS busbar residual voltage is measured in sulfur hexafluoride gas. The decay characteristics of the GIS busbar residual voltage under different polarity, different amplitude voltage and different temperature are studied. Research shows that the GIS busbar residual decays exponentially, and the decay of residual voltage is closely related to amplitude, temperature; at 26 °C and 0.4 MPa SF6 gas, the decay time of the GIS busbar residual voltage is as long as 22 hours after applying +450kV DC voltage, and the decay time constant is about 10⁴ s order of magnitude.

In recent years, the reform of China's pension system has aroused widespread concern in the society. Whether it is to provide for the elderly in housing, delay the retirement period, or increase the pension insurance, these are nothing more than the pressure problems faced by China's aging population. Indoor environment is the place where the old people who live in old-age facilities spend the longest time in a day, so its reasonable design is even more important. From the perspective of the overall design of space environmental art, this paper discusses the design method of indoor art wood based on the influence of environmental art design based on environmental science on the indoor environment of Jiangnan old-age building. According to the physiological and psychological characteristics of the elderly, some problems in the indoor environment design of old-age facilities are deeply analyzed and discussed, so as to create a good living environment for the elderly.