Table of contents

PREFACE

ACPEE 2018 was held in Kitakyushu, Japan during Mar. 22-24, 2018. ACPEE 2018 was organized by Hong Kong Society of Mechanical Engineers, supported by Kitakyushu Convention and Visitors Association, Auckland University of Technology, American University of Madaba (AUM). The conference provides a useful and wide platform both for display the latest research and for exchange of research results and thoughts in broad Power and Electrical Engineering, Renewable Energy and Smart Grid. The participants of the conference were from almost every part of the world, with background of either academia or industry, even well-known enterprise. The success and prosperity of the conference is reflected high level of the papers received.

The proceedings are a compilation of the accepted papers and represent an interesting outcome of the conference. This book covers 3 chapters: Renewable Energy & Smart Grids; Power and Electrical Engineering; Power electronics.

We would like to acknowledge all of those who supported ACPEE 2018. Each individual and institutional help were very important for the success of this conference. Especially we would like to thank the organizing committee for their valuable advices in the organization and helpful peer review of the papers.

We sincerely hope that ACPEE 2018 will be a forum for excellent discussions that will put forward new ideas and promote collaborative researches. We are sure that the proceedings will serve as an important research source of references and the knowledge, which will lead to not only scientific and engineering progress but also other new products and processes.

Prof. Tek-Tjing Lie, Auckland University of Technology, New Zealand

Prof. Moustafa Eissa, Helwan university, Egypt

List of Committees are available in this pdf.

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

In this paper, we propose the idea of the power intelligent test system by combining the concept of Cyber Physical System. And research the ways to organize information to make the intelligent test system of power is more heterogeneous, high degree of autonomy, adaptability and scalability. At the same time, to achieve high utilization and the Intelligence of the test data.

Malaysia has started encouraging renewable energy technology in 7th Malaysia Plan. However, inadequate power distribution in the island makes diesel generator important power sources which cause pollution. Some initiatives have been made by installing wind turbine and solar panel to reduce the dependency on generator. The hybrid PV/wind system is a good combination as solar radiation is high during the Southeast Monsoon, and strong wind during the Northeast Monsoon. Since the wind speed and wave height has a strong tie, during windy season, the wave height can go up to two meters. However, the feasibility of wave energy as power supply hasn't been explored. This paper focuses on the feasibility of using wave energy system to supply electricity to an island using HOMER. The obtained results show that a hybrid wave energy system has lower potential with cost of electricity (COE) is RM 1.303/kWh compared to the most optimal system, hybrid PV-battery generator, with COE is RM 1.262/kWh.

Smart Meters provide detailed energy consumption data and rich contextual information which can be utilized to assist energy providers and consumers in understanding and managing energy use. Here, we present a novel approach using genetic algorithms to infer appliance level data from aggregate load curves without a-priori information. We introduce a theoretical framework to encode load data in a chromosomal representation, to reconstruct individual appliance loads and propose several fitness functions for the evaluation. Our results, using artificial and real world data, confirm the practical relevance and feasibility of our approach.

Hydropower is a natural renewable energy with outstanding technological superiority in short-term operation. Short-term hydro generation operation (SHGO) requires not only lord dispatch in single station, but also the coordination of hydraulic and electric connection for different stations. In this paper, a coordinated peak shaving operation method of cascade hydropower stations is proposed. Firstly, regular pattern of peak load regulation is analyzed using the load characteristics of power grid. The daily power output of cascade hydropower stations should meet the needs of typical load pattern. In order to satisfy comprehensive utilizations of water resources, the outflow of each reservoir should be no less than the demand of water supply or irrigation. To verify the feasibility and effectiveness of the proposed method, an application of Pankou and Xiaoxuan cascade hydropower stations, located in Hanjiang River in China, is presented in this paper. Simulation results indicate that the proposed method can obtain the maximum peak shaving amplitudes and suggested peak shaving amplitudes at the same time, which satisfies different operation demands of cascade hydropower stations.

Due to the fact that Sine Cosine Algorithm(SCA) may easily premature convergence, by taking cultural algorithm as the framework of population space and using chaotic search to lead the evolvement of belief space, a new Chaos Cultural Sine Cosine Algorithm (CCSCA) was present in this paper. And the results of typical benchmark functions show that CCSCA has better global searching ability than SCA to avoid the premature phenomenon. Finally, CCSCA was employed for optimal operation of cascade hydropower stations (OOCHS), and case study showed that CCSCA could get satisfying results with high accuracy and fast efficient, thus providing a new efficient method to solve OOCHS.

Suffering strong El Nino, the middle and lower reaches of the Yangtze River experienced extreme rainfall anomalies during the Bai-U rainy period (19th Jun. to 20th Jul.) in 2016. The 21 reservoirs including Three Gorges reservoir in upper Yangtze River were operated together to control flood. Most of these reservoirs are distributed on Jinsha River, Ya-lung River, Min River, Chia-ling River, and Wu River. They totally offered about 37.3 MAF available storage with 29.2 MAF for flood storage. This paper analysed the operation performance of the 21 reservoirs during the Bai-U rainy period. It evaluated the joint operation performance of 21 reservoirs, and proposed suggestions for multi-reservoir management of Yangtze River upstream in the future. The experience of operating multiple large reservoirs would inspire others to utilize reservoirs crossing multiple rivers solving flood problems in a better way, facing the new challenges from climate change.

Flood control operation is the top priority for the management of the Yangtze River. To improve the timeliness and reliability of operation decision, it is of great significance to establish a set of intelligent decision system for flood control management, which can serve multi-level users. In order to achieve the goal, the key is to modularize the core business functions through the construction of topology relations of river network and control sites for the Yangtze River. In this paper, it would integrate the functions of hydrological forecast, flood propagation, flood control operation and flood risk analysis for the core business. Based on the core business model and information expansion interface, we develop flood control decision support system of the Yangtze River by virtue of GIS visualization and interactive WebService technology. The system can realize the real-time query of water-rainfall information and the fast-time simulation of flood control scheduling scheme, so as to provide the professional, scientific and accurate technical support for the group decision in the flood control.

In order to give full play to the power generation benefits of the Three Gorges Project, this paper based on the concept of floodwater utilization, studied the flood control modes of the Three Gorges Reservoir in flood season by combining the hydrological forecast in the middle and upper reaches of the Yangtze River. The benefit and risk of flood resource utilization was compared. The results show that through the implementation of flood control and utilization scheduling of the Three Gorges Reservoir in flood season, under the controllable of flood risk, the power generating capacity of the Three Gorges Reservoir in flood season can be increased by 933 million kW · h, and power generation overflow decreased 4.1 billion m³ per year, which can effectively raising the power generation benefit of the Three Gorges Reservoir and providing important technical support for the scientific dispatch of the Three Gorges Reservoir.

Due to the increasing energy demand and the lack of comprehensive utilization of water resources, this paper has established a generation-shipping-ecological optimization (GSEO) model to Balance the benefits between shipping, power generation and ecology. then, the Three Gorges Cascade (TGC) is taken as the research object, and the efficiency evaluation methods of shipping and ecological benefits are proposed. Finally, the actual inflows of the abundant, average and dry years are studied as the samples to solve the GSEO model. The simulation results indicate that the model and the benefit evaluation methods proposed in this paper are feasible and effective.

In order to explore operation scheme of downstream controlling reservoir in water source area for optimized allocation of inter-basin water resources, this paper selected the south-to-north water diversion middle route project in Hanjiang River basin as an instance. The optimized dispatching mode of Danjiangkou Reservoir is built with multiple dispatching objective functions and different dispatching scenarios set, such as maximum water supply during water supply period, minimum discharge, minimum abandoned water and maximum power generation. The simulation results indicate that the model and methods proposed in this paper are feasible and effective.

This paper intends to contribute, presenting a feasibility study for the implementation of a PV hydro hybrid system in Laranjeiras dam, in southern Brazil, with photovoltaic panels on floating structures. The study was carried out using software HOMER, which exported 8 760 annual values of solar radiation for the city of Três Coroas, and the power to be generated by the hydroelectric plant was determined from 8 760 hourly values of the Canastra turbinated flow, which were made available by CEEE. The study determined that the operation of the hybrid system would be optimal, by installing a hydroelectric plant at the foot of the dam, with 1 497 kW of installed capacity, operating with photovoltaic panels on the dam's water mirror, with a minimum capacity of 180 kW installed, and with 400 kW as a limit to purchase and sale energy to grid, to meet consumer demand up to 40 MWh/d. This combination would result in an initial cost of US $ 3 984 885 / kW and an energy cost of US $ 0.026 / kWh.

The electric power of generator P_e and bus voltage of network V have a strong nonlinear coupling relationship with other variables, which results in bad effects on the convergence procedure for the alternating solution method during the power system dynamic simulation using the SDC integration algorithm. Deep research was conducted into this problem. The convergence procedure for P_e and V was illustrated during the simulation, and prediction techniques by applying the Lagrange interpolation to construct a better iterative initial value with smaller error for them was proposed. Based on the SDC simulation method, the proposed method was tested on an IEEE standard 3-generator 9-bus system on the platform of MATLAB, and results show that the prediction techniques performs quite well for the acceleration of convergence procedure P_e for V and and simulation efficiency of SDC integration algorithm.

To measure sustainable loading capacity of photovoltaic/energy-storage system, indexes for sustainable loading power margin and energy margin are defined. With this basis, a dynamic islanding strategy for distribution system with photovoltaic/energy-storage system is proposed. The reliability assessment algorithm of the distribution network is improved based on Monte Carlo Simulation, by considering the fluctuation of PV output and load demand. Finally, it conducts a reliability assessment for modified RBTS Bus6, and results of simulation show that the proposed strategy can ensure continuous and stable operation of important loads within Micro-Grid, and enhance the reliability of distribution network.

In this paper, a kind of PV grid-connected inverter suitable for low voltage ride through is proposed. In order to alleviate the voltage drop at the power grid access point during the fault, the photovoltaic inverter needs to provide a certain amount of reactive power support to the power grid. The orthogonal quantities in the time domain are transformed into direct quantities by the dq rotating orthogonal coordinate system, so that decoupling control of active power and reactive power can be achieved. In order to achieve the smooth switching of the working mode, the parameter design of the PID controller needs to be analyzed according to the controlled object model. The simulation results show that the photovoltaic grid-connected inverter under the decoupling control can realize the reactive power support to the voltage drop at the grid-connected point in time.

Along with the increasing penetration of wind power into power systems, more accurate forecast of wind power becomes more and more important for real-time scheduling and operation. This paper proposes a novel model for short-term wind power forecast based on singular spectrum analysis (SSA) and self-organizing maps (SOM). In order to deal with the impact of high volatility of the original time series, SSA is utilized to extract the mean trend from the original time series. After that, SOM is applied to select the similar segments from mean trend, which are then employed in local prediction by support vector regression (SVR). Simulation studies are conducted on real wind power time series, and the final results indicate that the proposed model is more accurate and stable than other models.

Application of gas-fired units and power-to-gas devices promotes coupling between power system and natural gas system, and hence provides an alternative solution for the wind power integration. Also, the traditional stochastic optimization and robust optimization methods may result in uneconomic or conservative decisions in dealing with the uncertain problems. Thus, a data-driven based distributionally robust dispatch model for the integrated electricity and natural gas system is proposed in this paper, which is constructed in a two-stage optimization fashion. The day-ahead total cost for the integrated system is regarded as the optimization objective in the first stage where the forecast wind power information is also taken into consideration while the output adjustment of thermal generation units and the supply regulation of natural gas source are included in the real-time dispatch (second stage in this study). Besides, the norm-1 and norm-inf are simultaneously combined to constrain the confidence set of wind power probability distribution. Then the model is solved by the Column-and-Constraint Generation algorithm. Finally, numerical results verify the effectiveness of the proposed model.

The increasing integration of high penetration of wind power into power systems have created great challenges for stable operation of the power system. It is important to design a reasonable demand response scheme (DRS) to make decision the optimal load relief, specially, for the wind power suppliers (WPS) and their customers (WPSC). Therefore, this paper proposes a demand response scheme for wind integrated power system based on mechanism design theory. Firstly, we derive the outage cost function and incentive function modeled by the two variables: the customers' type parameter and the location value. Secondly, incorporate customers' type parameter and locational flexibility into the DRS, and based on game theory, a demand response scheme with incentive compatible constraint and participation constraint is designed to maximize the benefit both the wind power suppliers and their customers. The implication of demand response scheme is to design an incentive structure that encourages customers to sign up for the right scheme and reveal their true value of load reduction. Finally, the eight-bus system example can demonstrate the effectiveness of the proposed method.

By researching on the mathematical model of small danielle wind generators, it is easily to find that reasonable load connection and disconnection or changing the load characteristics could control the rotational speed and output power of wind generators. Using the controlling strategy combined with switching braking resistor and three-phase short-circuit braking, the rotational speed of wind generator could be controlled accurately in the scenes of sustainable strong wind or the wind speed continuously increasing. At the same time, users' cost could be ensured. A lot of field experiments had proved the feasibility and practicality of the controlling strategy. The research of this paper would promote the application of small danielle wind generators.

Large-scale grid connected wind farms are the main development trend of wind power in China. In the planning and design stage of wind farms, a simplified equivalent model is often used in wind farm equivalents. It makes the wind farm simply equivalent to a single wind turbine, neglecting the change of wind speed correlation caused by the terrain effect. This makes a large error in estimating wind power. In order to solve this problem, a method based on wind speed correlation is proposed to cluster the wind farm of complex terrain. By using the mixed Copula function with tail characteristics, a wind field correlation model with complex terrain features is built. Based on that, EM function is used to identify the Copula function parameters, and the equivalent clustering method of wind farms is built. Finally, the simulation analysis shows that the complex terrain wind farm clustering equivalent method considering wind speed correlation is verified.

In the new era, the Northeast power grid is facing a series of opportunities and challenges. In this paper, the strategy of "complementary", "transmission" and "mutual benefit" coordinated development of Northeast China Power Grid and national energy grid is formulated based on the relevant national policy planning; Considering the difference of unique geographical location, natural resources, human resources, technology and other factors of the northeast and other areas; taking into account the development situation and future development needs of all regions, formed a coordinated development strategy layout, covering the unified planning, new energy development, peaking capacity construction, power substitution and talent support. It is beneficial to improve the efficiency of the national energy allocation and utilization, and to solve the practical problems faced by the power grid, so as to realize the coordinated development of the Northeast Power Grid and the national energy grid.

Wireless sensor networks are self-organizing networks composed of a large number of energy-limited sensor nodes. Due to the factors such as distributed power, energy storage equipment, power load density, operation mode and geo-environment in the microgrid region of the new energy grid, each device in the new energy microgrid has multiple regions and diversified forms, So it is difficult to carry out a unified real-time monitoring. Therefore, this paper designs to integrate the detailed operation status of the independent new energy power supply network into the existing station monitoring system through the wireless sensor network to implement unified energy management. According to the real-time acquisition, immediately to take appropriate measures to greatly improve work efficiency.

Wireless sensor network (WSN) is a self-organizing network composed of a large number of energy limited sensor nodes. As the wireless sensor network in new energy micro grid environment may be close to the node receiving station due to the amount of traffic and the first run out of energy, resulting in shorter life cycle, part of the micro network environment for many sensor nodes, working environment and other factors can not be timely replacement of batteries, the reliability of sensor network is difficult to guarantee. Therefore, this paper optimizes the design of LEACH routing algorithm. The simulation results show that the improved routing algorithm has obvious advantages in prolonging the lifetime of sensor networks.

In traditional wireless sensor networks, the node battery capacity is very limited, which seriously restricts the sensor network long time monitoring operation. Therefore, how to improve the life cycle of WSN has always been the focus of research. In order to ensure the normal operation of WSN as long as possible, the energy of nodes must be utilized to the maximum extent. in this paper, Based on the wireless transmission technology, the mobile wireless charging equipment, energy supplement of rechargeable sensor nodes deployed in the complex environment, solve the network energy bottleneck problem essentially, effectively reduce the node failure rate, greatly improves the network lifetime, has broad prospects and research value.

The channel environment of the new energy microgrid is worse than the traditional power line. On the one hand, the grid connection and switching of a large number of energy terminals in the new energy microgrid will change the impedance characteristics of the power grid and thus affect the transmission characteristics of the power line carrier communication. At the same time, the new energy terminal grid-connected devices make extensive use of power electronic devices, making the noise of the power grid more complicated and greatly different from the noise distribution in the traditional power distribution network, which makes it difficult to detect the carrier communication signal. This article broadband PLC system uses OFDM technology as an effective way to overcome the multipath fading modulation. Although broadband powerline OFDM systems represent the direction of broadband PLC technology, the communications capabilities and quality of service currently provided by the technology are far from broadband telecommunications service standards and require further optimization.

The rapid development of electric vehicles (EVs) and distributed generations (DGs) has brought new challenges to the safe and economical operation of power system. This paper mainly works on how to optimize the management of plug-in EVs in the distribution system with fixed DGs, in order to achieve the economic and stability in power grid. Firstly, the management characteristic of EV is discussed and classified to obtain the access probability model. Secondly, being in distribution network investors' shoes and considering the constraints of distribution network, DG, ESS and EV, the economic management of EV optimization bi-level model is established with the objective function of maximum annual income and minimum fluctuation of output power of equivalent load. Then the genetic algorithm(GA) is used to solve this model. Finally, the experimental results of 33-bus system with DGs and EVs verifies the effectiveness of the proposed method, and the influence of different penetration of EV on the annual income of distribution network is also analysed to provide a new idea for the future development of distribution network.

Preventive maintenance of wind turbine can effectively improve the reliability of wind turbine. This paper firstly set single component reliability of wind turbine as constraint condition, single component minimum unit time maintenance cost as objective function to obtain optimal maintenance cycle and maintenance times. On this basis, repairing component which meet certain conditions, then build opportunistic maintenance model of wind turbine. Lastly, set the minimum total cost under opportunistic maintenance as objective function, the wind turbine availability as constraint condition, then solve this model to obtain optimal threshold of opportunistic maintenance and minimum total maintenance cost using genetic algorithm. The example analysis shows that the model can effectively save the total maintenance cost. This study has some reference significance for the maintenance department to make the maintenance plan.

Nowadays, the transient overvoltage occurs in offshore wind farms has aroused widespread concern. To improve the existing offshore wind farm model's accuracy in high frequency conditions, this paper proposes a high frequency model of the vacuum circuit breaker as well as a shunt reactor model considering the influence of stray capacitance. After that, a model of a typical offshore wind farm is constructed for the purpose to analyze the overvoltage occurring at bus bars and wind turbine transformers in the process of connecting a shunt reactor. Simulations show that connecting a shunt reactor in offshore wind farms cause overvoltage of high peak and high steepness compared than with those in onshore wind farms.

Electric Vehicles (EVs) are one of the renewable energy sources that can bring significant positive impacts to power system during their charging and discharging operations. According to this research an educational tool has been created to show students/users the Electric Vehicle's behavior when integrated to the distribution grid. This research helps students/users to develop new algorithms for renewable energy and energy storage applications. A Matlab/Simulink module has been utilized to implement the integrated systems with simple, easy and flexible Graphical User Interface (GUI) for experimentation purposes. Furthermore, the developed educational tool aims to show that EVs can be efficiently charged by renewable energy sources connected to the grid with reduced charging costs. In addition, users can understand how those results can be sustainable for further studies and development. Unlike commercial wise tools, such a tool would add a promising methodology for the research methods and educational systems due to availability and user friendly approach.

This paper presents an improved technique to generate damped AC voltage for on-site PD detection on distribution power cables. The proposed technique is based on conventional frequency-tuned series resonant system and two additional high-speed switches. In order to reduce the size and weight of the proposed damped AC test system, electric simulation by Simulink and heat simulation by ANSYS are carried out to determine the system parameters. High-voltage test on two 10kV XLPE cable segments was conducted to validate the proposed technique.

To provide a more convenient and efficient method for detecting partial discharge (PD) on XLPE cables, this paper describes a 0.1 Hz cosine-square wave testing system, which can output peak voltage up to 30 kV. Due to L-C series resonance principle, the wave of discharge process is in cosine form which can be equivalent to AC voltage. Therefore, PD detection can be conducted under the rising and falling edges. The vital component of the proposed system is high-voltage semiconductor switch which consists of several series connected IGBTs. Based on the idea of compactness, a prototype system is integrated in the lab. Withstand test and PD detection test are also carried out to validate the proposed system. The experiment result shows that the system is effective to detect PD signal in power cables and has certain development prospects on insulation condition assessment of XLPE cables.

The corestructure of inverter DC-link bus film capacitor is too complex, it is more urgent to build the simulation model oncapacitor core loss. Thus, in this paper, the current distribution and the loss distribution of thin film capacitor metal plate were analyzed, and then the mathematical expressions with current distribution and loss distribution were derived on the capacitorplate. On this basis, the concept of equivalent resistivity is put forward, and thelossmodel of equivalent capacitor core was established. By this method, the simulation model with capacitor core was simplified and verified by simulation. At the same time, the structure model of thin film capacitor core was established, and the influence of different core terminals and core shape were analyzed in thefilm capacitor.

The reliability of active distribution system is important for power system operation and users convenient. In order to evaluate the reliability of distribution system quickly and effectively, this paper established the output model of photovoltaic generation system and wind turbine generators considering more random factors. Then considering that the calculating complexity bring by above model and Monte Carlo method, this paper provided network simplification method based on feeder partition. Then this paper designed parallel calculation project for reliability evaluation to improve calculating efficiency. At last, simulation example verified the effectiveness of active distribution system reliability evaluation.

With the continuous development of electric vehicles, a large number of electric vehicles have connected to the grid. This impacts the security and economic operation of power systems deeply. When large-scale electric vehicles are charging, it will bring the problem of electricity load growth and cause the peak-valley difference of power grid. The paper analyzes the impact of electric vehicles quick charge on power quality. According to Monte Carlo method, the daily load curve of quick charging mode in Beijing in 2030 is set up. Newton Raphson method and forward-backward substitution method are used to analyze the voltage deviation and power loss of each node in the typical power system.

Nowadays, alarm information collected by dispatching and control systems is increasing substantially and the problem of frequent and false information happens occasionally, which may influence the operation status analysis of power grid and the following work of big data mining and cloud-computing. Thus this paper proposed an optimal D5000 alarm data platform, using the intelligent techniques like alarm restraining, information folding, etc. Besides, assessment index system was also established to analyse the optimized effect of the alarm data processing system, adopting the fishbone diagram and improved Grey incidence approach. The practical results show that the optimal platform is practical and valuable in following aspects: eliminating redundant and interference information, reducing the man-made missing or judging problem of urgent and important information, improving the big data analysis and management, and so on.

Aiming at the problem of the increasing voltage over limit risk by a large number of distributed PV access network, firstly by analyzing the volatility and time-series property of the PV output, a probability model of PV output based on the clearance model is established in this paper. Then the risk assessment index of system voltage exceeding the limit based on the probability and severity of node voltage at each time interval is established. Based on this, using the hybrid approximation to solve the ultimate capacity of distributed PV access network is proposed. Finally, a typical IEEE 33-node power distribution system is taken as an example to analyze the risk of system voltage under different load characteristics, load levels and line types. From these three aspects, the ultimate capacity of distributed PV access network is evaluated.

Rapid increase of wind power installation brings new issues and challenges for grid security operation and one of the most important key issues is reactive power and voltage control capability of wind farms. This paper proposes a coordinated voltage control strategy for power system with wind farm based on equivalent input disturbances (EID) compensation. Firstly, the voltage control model of power system with wind farm based on doubly fed induction generator (DFIG) is established. The power system adopts reactive power compensation device for voltage control, and the wind farm connected to the grid adopts frequency converter of DFIG to adjust reactive power output. They can coordinate each other to realize voltage stability control of the wind farm connected to the grid. Moreover, when the system is subjected to load disturbance or wind speed disturbance, the proposed method based on EID compensation also can keep the voltage stability of power system with wind farm. Finally, the simulation results show the feasibility and effectiveness of the proposed voltage coordinated control method in voltage regulation.

In order to solve the problem of single-phase grounding fault judgment in non-solid-earthed distribution network, the power flow in non-solid-earthed distribution is analyzed. The steady-state current value in the upstream fault phase will be abruptly changed, and the current in the downstream fault phase will keep the load current constant. The steady-state current values in other non-faulty phases and non-faulty lines do not change abruptly. A single-phase grounding fault judgment method based on steady-state current characteristics is proposed. The power supply path real-time current matrix, the power supply path history current matrix, the power supply path mutation current matrix and the power supply path mutation current logical matrix are established. The problem of the single-phase grounding fault judgment is transformed into the matrix operation problem. The detailed calculation formulas are given. The simulation results show that the method proposed in this paper has a good adaptability to the permanent grounding fault and it is worth popularizing.

Cable accessories, as an important part of cable system, we often only focus on its initial acquisition costs and ignore the late costs in its life cycle. In order to maximize the economic benefits and to play the use of cable accessories, we need to introduce an equipment life cycle cost management (LCC) for 110kV cable accessories. In this paper, a life cycle cost management of 110kV cable accessories is studied, and an evaluation model of cable accessories purchase based on LCC is established. The LCC theory is applied to the bidding and purchasing of cable accessories, which can make the purchased and managed reasonably, and save the social resources effectively.

This paper, for the first time, compares the probabilistic optimal power flow (POPF) models targetingdifferent objectives -- minimizing the expected generation cost (EGC) and all-side risk (AR) or down side risk (DR)simultaneously. In the POPF models, wind power generation isconsidered in dispatching, the uncertainty of which can be explained by building a model to describe the stochasticcharacteristic of the forecast error. The distribution of the forecast error can be obtained by sampling from the historical error time series. The POPFsaresolvedusinggroup search optimizer with multiple producers (GSOMP), and a decision-making method TOPSIS is used to select the most suitablesolution. Simulation studies are conducted on a modified IEEE 118-bus power system with wind farms integrated, and the results show that the EGC-DR modelfind better solution compared tothe EGC-AR model.

In this paper, the objectivity and unpredictability of the three-phase load unbalance (TPLU) for the rural distribution network are proposed. Firstly, the influences of TPLU on the power quality and power loss are analyzed. And then, based on the common managements and governance measures of TPLU, whose typical problems are also introduced. Furthermore, based on the fast phase selection, the concept of the three-phase load balance is defined to describe the basic structure and complementation principles in detail. Lastly, the operating points and control strategies of the commutation equipments are proposed. The verification results show that proposed method is accurate and effective.

The output of the controllable distributed generation (DG) is determined by the economic dispatch strategy of the active distribution network (ADN). When we calculate the load supply capability (LSC) of ADN, the influence of the economic dispatch results must be taken into account. This paper proposes a bi-level optimization model for maximum power supply capacity of ADN based on chance constrained programming. The upper level model is used to calculate the LSC, and the lower level considers the economic dispatch of controllable DGs. Based on the improved IEEE-33 distribution system, the results show that the model can get the maximum power supply capacity that meets the economic operation requirements of ADN.

Real time human action recognition is to recognize the human motion type based on skeleton movement in real time and is always a challenging task. In this paper, a novel method is proposed to accomplish the classification by using Spiking neural network (SNN) which is biology oriented neural network dealing with precise timing spikes. First, a new temporal encoding scheme is used to encode the real time motion capture data into a series of spikes and the according type of the motion is represented by a spike time. Second, a two-layered spiking neural network is initiated and trained through a gradient descent learning algorithm. The experimental results show that this method achieves a good learning precision and generalization.

In this paper, a new method for real-time prediction of building energy consumption is proposed, this method solves the problem that the kinds of energy consumption are not distinguished and the prediction accuracy is low in the current energy consumption prediction algorithms. This paper divides the total energy consumption into four sections. Firstly, three main influencing factors of building energy consumption are extracted using PCA to realize real-time prediction; Secondly, the method of lighting energy consumption prediction based on time series analysis is constructed, the lighting energy consumption of the building is predicted in real time. Finally, the energy consumption prediction model based on BP network is established to predict the air conditioning, power and special energy consumption of the building. The experimental results show that the prediction model can predict energy consumption in every part of a building more accurately and effectively.

A novel double closed-loop control of VIENNA rectifier based on sliding-mode of fuzzy approaching law is proposed in this paper. This new control strategy improves dynamic response and steady accuracy of system, chattering phenomenon of the sliding-mode is eliminated. Combined with sliding-mode and fuzzy approaching law, a new type of inner loop power control is proposed to replace traditional current inner ring. Without coordinate transformation and phase-locked-loops(PLL), control algorithm is simple. Under unbalanced three-phase power grid, output voltage still maintains small voltage ripple, network side harmonic suppression and dynamic response perform well. Sliding-mode based on fuzzy approaching law can eliminate the chattering phenomenon of the system, the overshoot produced by load transition can be reduced. The outer ring adopts voltage PI control with real time current compensation, dynamic response performs good and the control algorithm is simple.

In order to reduce influence of the total inertia of the system on the system stability, the virtual synchronous generator(VSG) technology is becoming a research hotspot for the penetration of distributed power supply with high permeability. Due to the existence of the current limiter in the inverter, the transient energy function which is constructed by first integral (TEF) derivative is not monotonous. It may make using TEF method to obtain the critical clearing time and system stability error. This paper proposes an improved TEF method using the tangent function to replace the saturation one. Firstly, the relationship between the virtual power angle and the power angle of the traditional system is analyzed after the improvement of the inverter current saturation link. Then, the first integral method is used to construct the TEF with improved saturation. Finally, it simulates to a single machine infinite bus system and IEEE three-machine-nine-bus system by MATLAB/Simulink, and the results show that the improved TEF is proposed, it can effectively evaluate the VSG strategy and the transient stability of AC system inverter current limiting.

The most existing short-term nodal load forecasting methods only focused on the application of separate historical data, ignoring the abundant redundant information in power system. In this paper a new nodal load forecasting method considered physical redundancy and measurement redundancy was proposed. Firstly, the effect of redundant information on short-term nodal load forecasting was analysed and the forecasting principle was given. Secondly, in order to form additional state variable measurement equations, two kinds of existing redundant information between state variable and measured values were analysed deeply. Then based on the forecasting principle and the analysis results, the forecasting model mainly imitated the form of state estimation was established and the specific forecasting process was given. Case studies demonstrated that compared with traditional support vector machine model, the proposed method could effectively decrease forecasting errors and improve forecasting results.

A power grid reactive power optimization algorithm was proposed in this paper to ensure that distribution network systems run efficiently, which is called the opposition-based chaos shuffled frog leaping algorithm (OCSFLA). A mathematical model of reactive power optimization was established based on the consideration of the constraint conditions. The initial swarm of the model was optimized based on the opposition strategy. The leading role changed gradually from the shuffled frog leaping algorithm to chaotic search in the iterative process by setting the appropriate chaotic variables. Thus, the global optimal solution was searched more quickly. In the simulation tests of the IEEE30 system, the results show that a better compensation effect was obtained when the reactive power compensation was performed in nodes 12 and 24. After completing the reactive power optimization based on the improved leapfrog algorithm, the active network loss value of the system was reduced by 13.85%. The algorithm was more efficient compared with other traditional optimization algorithms because OCSFLA can avoid falling into local optimization.

The smart substation adopts the network communication rather than the traditional electric cable, which makes the traditional secondary electric circuit terminal into a loop of virtual terminal and then the entire secondary system became a "black box", thus causes a lot of problems and difficulties into the operation and maintenance of smart substation. However, little attention has been paid to the visualization of secondary safety circuits for smart substations. In this paper, a portable device based on the characteristics of the secondary circuits and needs of the current secondary safety measures for smart substation was designed to realize the visualization of the device information, the control circuits and the safety circuits. Finally, the secondary security measures of smart substation were normalized and illustrated based on the first set protection of 220 kV line space.

The authors describe the mobile cyclic accelerator based on the ironless pulsed betatron. The possibility of such accelerators application as a part of mobile radiographic complexes is illustrated. These complexes are intended for the radiography of dynamic objects with large optical thicknesses located in the explosion-proof chamber (EPC). Such complexes allow optimizing the radiography geometry in the hydrodynamic experiment at the expense of the possible location change of the radiator and recorder relative to the investigation object. The geometry optimization allows increasing the X-ray radiation intensity in the recorder plane at least twice if compare with the active Russian radiographic complexes. The authors provide the output parameters of the mobile cyclic accelerator at its testing powering on the test bench. The value of a capacitive storage of the pulsed powering system of the betatron electromagnet was C=900µF (C_max=1800 µF). The thickness of the lead test object examined with X-rays was ≈100 mm at 4 m from the tantalum target; the dimension of the target was 6×6 mm². The full width of the output gamma pulse at half maximum in a single frame mode was ≈100 ns. The dimension of the radiation source was ≈ 6×3 mm².

Electricity is the foundation of the national economy, and the influence on the social and economic development is self-evident. At the same time, the power industry is also deeply affected by the economy and society. Firstly, this paper introduces the new environment faced by Northeast power industry from four aspects: power system reform, bilateral stochastic system, technological innovation and related policies; then It deeply analyzed the impact of the new environment on the development of the Northeast Power Industry from the above four angle; finally, the opportunities and challenges of the new environment for the future development of the Northeast power industry are summarized. To pave the way for the formulation of Northeast power grid development planning, and it is also helpful to improve and scientificity and accuracy of the Northeast Power Grid Planning.

Based on the analysis of smart grid features and business requirements and using the existing research results of heterogeneous networks for reference, this paper designs a heterogeneous network model and functional architecture that adapt to the smart grid environment. Based on this, according to different network resource status, the paper analyzes and compares the network discovery, network selection and connection management mechanism in multi-network environment which includes multi-level, heterogeneous network environment to support the transmission diversity common link layer processing technology; and business multi-network collaborative bearer technology to improve the flexibility of access to a variety of services in power communications.

As the carrying network of electric energy, the power grid is the foundation of the national industry. For the implementation of the "Internet plus" strategy, there is an urgent need for a new network communication technology to improve the traditional power communication network, and to make up for the original defects. This paper mainly analyzes the new demands of new intelligent power business of communication network. Then, the limitations of existing power communication network and power distribution equipment are explored. At last, It put forward the basic scheme of using SDN technology to improve the existing power communication network, which provides a train of thought for the design of intelligent power distribution system based on SDN Technology.

Aimed to improve the ability of EON (Elastic Optical Networks) to support multiple services brought by Energy Internet, this paper proposes a Echo-State-Network Based Services Awareness schem of EON system for Energy Internet. The proposed scheme is able to be aware of characteristics of multiple services and to match their requirements with better quality. Thus, resources allocation optimization is enabled by the proposed scheme in each edge node. Simulation results show that this proposed approach can greatly improve the supporting ability for multiple services of Energy Internet with better performance from aspects of both packet loss rate and time delay performances.

In view of the traditional electric power communication network terminal access to the lack of unified management and control of the situation, based on the analysis of heterogeneous network management technology and channel protection technology of current mainstream access network communication methods in resource dynamic changes of frequency, time slot and cyber source; smart grid multi services in heterogeneous network integration under the bearing design scheme and choose to create favorable conditions for the optimization of communication terminal access.

The large-scale access of the distributed photovoltaic power supply to the grid will bring great challenge to the safe operation of power grid, thus adversely affecting the further development of distributed photovoltaic. First of all, from the aspects of structure, power quality, network loss and relay protection, this paper summarizes the influence of distributed photovoltaic system on distribution network. Secondly, the distributed photovoltaic output is summarized and summarized from two aspects of distributed photovoltaic output performance analysis and output forecast. In addition, from the perspective of photovoltaic user demand response can improve the photovoltaic extinction rate, this paper also combs the analysis and research of PV user demand response modelling and electricity price mechanism. Finally, some suggestions on the key areas for future research are put up.

The localization of multiple partial discharges based on UHF signal is difficult to accomplish due to the excessive localization error. A virtual array extension method based on four-order cumulant and signal sparse decomposition is proposed in this paper. The virtually extended array has higher directional resolution and it could detect partial discharge sources with higher accuracy. The 2×2 UHF array that commonly used in existed partial discharge localization methods is virtually extended to 3×3 and 5×5 array. The virtual array extension is accomplished by extending the corresponding steering vector matrix of PD signal spatial spectrum to a overcomplete dictionary, which is then used to realize the sparse decomposition of the PD signal. Eventually the DOA estimation of multiple partial discharge sources is achieved. Simulation and field test results show that the virtually extended UHF array can detect and locate two PD sources simultaneously. The directional angel estimation error is about 6° and the pitch angle error is lower than 4°, which has proved the feasibility of the proposed method.

Control stability when Multi-level STATCOM is applied on weak power system is discussed in this paper. In order to research the stability of weak system quantitatively, the current inner open-loop transfer function with system impedance is presented. Nyquist curve is used to demonstrate the relationship between the system impedance and the system control performance. Then a new control strategy - adding the current's proportion-differential (PD) to the feed forward voltage, is proposed. This control strategy can eliminate the positive feedback action caused by system impedance. Finally, test result proves that the above theoretical analysis is correct.

Magnetic valve controllable reactor (MVCR) is a kind of reactive power compensation equipment with good control flexibility and high reliability, which as a result making MVCR being applied more and more widely. Therefore it is crucial to improve the performance of MVCR. In this paper, a method is presented for reducing the fringing effect by dividing one single magnetic valve of MVCR into several series-connected parts, which will reduce the corresponding inductance of AC winding. Consequently the equipment will generate more reactive power with the same working voltage and the control voltage as well as improving its performance. By theoretical analysis and simulation with software ANSYS, an optimal separation of MVCR's iron-core is presented in this paper which calculates the number of magnetic valves and the space length between every two of them. The validity of this design has been fully confirmed by specific experiments that under the same working voltage and control voltage, the current of the AC winding increases by 7.4% when a single magnetic valve is divided into two parts.

In the power system, the phase-check is a simple but very important work. The newly built, transformed and expanded power plant, transformer substation electrical equipment and power transmission lines before put into operation must be carried out phase-check test, in order to ensure voltage phase sequence and phase correct. At present, there are some limitations of traditional phase-check technology in China. In this paper, we study the method of unified reference source based on synchronized phasor measurement technology. Through the GPS time synchronization signal to realize synchronous sampling of source voltage signal in different regions, by comparing to the phase of a fixed reference source signal in the power network to determine the phase relationship between any two different power points, and thus to complete the work of phase-check. The unified reference source phase-check method based on the synchronized phasor measurement technique is simple, easy to operate, and has high efficiency, which has unique advantages. And wide area power grid phase-check can be realized.

Because of the complicated structure of cooling system, the heat radiation principle and top-oil temperature prediction of the split transformer is attracting more and more attention. This paper proposes a top-oil temperature prediction method for split transformer based on PSOGSA. Based on the thermal circuit of ordinary transformers, a thermal circuit for split transformers is proposed taking the heat radiation principle into account. Besides, the model is modified with the consideration of the non-linear heat resistance, load ratio and oil viscosity. Further, the parameters of the model are optimized by PSOGSA. Finally, the method proposed is tested by on-site temperature-rise experiment. The test results prove that the method could provide a high-precision prediction result of the top-oil temperature for split transformer.

The impulsive discharge characteristics of the air gap is one of the main bases for the design of the external insulation of high-voltage electrical equipment; meanwhile, air gap discharge characteristics at different altitudes have been of concern for a long time. In this paper, the impact discharge tests of rod-rod gaps at different altitudes were carried out to study the influences of elements such as electrode shape, voltage polarity, altitude and temperature. It can be found that, with the increase of the gap distance, the 50% impulse voltage of the switching impulse tends to be saturated, and the discharge characteristic curve can be fitted by exponential function. The 50% impulse voltage of the lightning impact and the gap distance shows a good linear relationship which can be fitted by the linear function. This is no direct relationship with temperature and altitude. The saturation tendency of switching impulse's 50% discharge voltage decreased with the decrease of temperature. With the increase of the altitude and the decrease of the 50% impulse discharge voltage, the polar effect of the air gap between the rod-rod and the rod-plate decreases. The results are of great reference value for Insulation configuration of electrical equipment in high altitude.

With the higher controllability and power supply reliability, VSC-HVDC transmission technology can support the grid connection of offshore wind power and other distributed energy resources, which conforms to the trend of energy revolution. For investors, the technical-economy effect of VSC-HVDC transmission project is the most attractive issue, and furtherly, the influencing factors are necessary when analyzing the technical-economy effect level of a certain project. To help investors identify the main influencing factors, arrange the internal relationship of influencing factors, and make investment decisions, this paper firstly builds an influencing factor set of technical-economy effect of VSC-HVDC transmission system using brainstorming method, and then proposes an improved ISM method to divide the hierarchical structure of influencing factors. The result shows that influencing factors can be divided into 9 categories and four levels, of which design requirements, equipment requirements and project features are superficial factors, while natural environment and policy environment are fundamental factors. The case study proves that improved ISM method is applicable and practicable for influencing factor analysis.

3 burning accidents of electromagnetic voltage transformer of Qinghai power grid in the southern high altitude area was introduced in this paper, and the cause of the accident was analyzed, which is due to a phase grounding line, then the other two phases voltage rising caused voltage transformer damaged; occurrence of Ferro resonance over-voltage, which resulting in serious core saturation, and the over-current caused voltage transformer damaged; due to open delta is short circuit, when the single-phase grounding fault occurred, because the voltage output of 100 V from open delta winding, a very large current is formatted, and a lot of heat is made, also led to the current in primary side very large, resulting in burning TV. In view of these three reasons, the corresponding prevention measures are put forward to ensure the normal operation of the power system.

The traditional distribution network reconfiguration method does not consider the impact of switching operations, resulting network equipments voltage instability and user blackouts in actual implementations. In this paper, the loop operation security constraints have been fully taken into account as establishing distribution network reconfiguration model by introducing constraints into the traditional model. The greedy random adaptive search procedures (GRASP) is adopted to obtain optimal solution and detailed steps of reconfiguration scheme and switching operation for distribution network, which ensures the solution is realized without network equipments voltage instability and user blackouts. After IEEE 14-bus system verification, this method shows its better adaptability and practical value, which fully combines actual work statues to improve distribution network reliability.

The performance of the smart electric energy meter deteriorates during the operation, which will affects the accuracy of energy metering. In order to estimate the smart meter's error during the operation, a method based on parameter degradation model is proposed. The meter's degradation parameters and degradation acting parameters are determined, aiming at building parameter degradation model and putting forward error estimation constraint. Big data analysis methods are adopted in the process of solving degradation network. As the data are of multiple categories and data changing rates are variable, pre-processing method of differential normalized data is employed. Additionally, feed-forward neural network is adopted to approximate degradation characteristics, because elementary function is incapable of describing degradation network. Therefore, the smart meter's error can be estimated according to the error estimation constraint, assuming degradation acting parameters pre-determined. Case analysis results show that estimation results using the proposed method is in accordance with operating state in short time, and absolute error is less than 0.1%, demonstrating that the error of smart meters can be estimated with this method effectively and dynamically.

The protection of Multi-terminal DC (MTDC) system is not straightforward. This paper proposes a novel protection technique for the proposed configuration topology of interconnection project between Egypt and Saudi Arabia. The proposed scheme depends on the second derivative of dc line current with the time which represents the acceleration of dc current with the time. A model of three-terminal Line Commutated Converter (LCC) MTDC with polarity reversing availability is used to study fault behavior and apply the proposed algorithm to detect and classify the fault. The proposed scheme is evaluated via an extensive simulation study for 500kV dc transmission network using Matlab©/Simulink©. The suggested algorithm detects a dc fault without communication link between the relays and can respond to different fault resistances and different fault distances in few milliseconds.

Nanosecond IFRA has the potential to realize online detection of power transformer winding deformation and displacement. But this method is not mature even in offline condition, and the reliability, accuracy and repeat ability of which are in doubt. To verify the reliability and accuracy of nanosecond IFRA a comparison experiment is conducted between it and a mature method which is applied widely all over the world, SFRA. In this experiment, three levels of axial displacements are experimentally simulated on a dry-type distribution transformer in the lab and both a nanosecond IFRA system and a commercial SFRA analyser are applied to obtain the frequency responses at each fault level separately. To verify the repeatability of Nanosecond IFRA, two Nanosecond IFRA measurements conducted in a time interval of 30 days with all the test condition remaining the same are compared. The results are analysed by visual inspection and quantitative comparison.

As the source of power line project, line design is a key part of life cycle management. The safety and reliability of line design can provide necessary support for construction, operation and maintenance. This paper proposes a risk-based approach for safety management in line design, decomposing risks into two dimensions, the probability and the consequence. Based on factors, such as risk assessment, number of historical incidents, consequence of historical incidents, qualification of proofreading and auditing, this approach in line design can predict risk status in real time, provide scientific basis for risk control, and minimize safety hazards.

Lightning faults of transmission lines are usually instantaneous faults, and most of them can automatically reclose successfully, but reclosing failure will also occur sometimes. The present paper analyses a reclosing failure of a 500kV transmission line after lightning strike. In this paper, the lightning monitoring system is used to monitor power frequency fault current and lightning transient traveling wave current, and the fault location, the cause identification and the reasons for the reclosing failure are obtained based on the monitoring data. The results show that there are several successive lightning strikes near the fault point of transmission line during the switch to closing period, which makes the fault frequency continuous current unable to return to zero, so the insulation cannot be recovered, which ultimately leads to reclosing failure.

Overhead line is an important asset for power industries. Rising demand in electricity, environmental concerns and cheaper electricity prices are some important factors behind operating the lines at their maximum potential. Replacing overhead lines and/or constructing new lines are not only expensive but also at the same time raise environmental concerns. However, rating overhead lines based on their natural capacity besides being cost effective is a technically feasible solution. In this project, the operational analysis of dynamic line ratings (DLR) is conducted to analyze potential of DLR when practically implemented across overhead line in a sub transmission network. It further guides system operators in fully utilizing the line capacity to its maximum potential. The project also investigates the impact of Flexible AC Transmission System (FACTS) device in the presence of DLR technique to control power flow from wind generators for stabilized and controlled transfer of electricity.

The metallurgical industry in China has developed rapidly, which has caused an increasing amount of exhausted gas emission. After a long period of operation, a layer of metallurgical contamination is deposited on the surface of insulators near the metal work, which may have an effect on the distribution of electric field on the surface of insulator. The chemical test indicates that the metallurgical contamination layer contains particles of Fe₃O₄ with strong conductivity, which may become suspended potential conductor. In this paper, the influence of thickness of contamination layer and diameter, arrangement of conductive particles on the electric field are discussed by the simulation model.

Intensive study of Partial Discharge (PD) phenomenon is of great importance for detecting and distinguishing different types of partial discharge. A portable device for partial discharge generation is designed and developed in this paper, which possesses advantage of miniaturization, dependability and flexibility. Such device is composed of power supply module, PD generating module and PD output interface. An implementing example of the partial discharge generator is given here in detail. Simulated high voltage signal is generated by a waveform generator and applied on physical PD generating model after being amplified by power amplifier and being boosted by a high voltage transformer with high transformation ratio. The generated PD pulse sequence are acquired and further analysed by MATLAB. Point to plane discharge is used as an example and verifies the performances of this device.

Partial Discharge (PD) detection aiming at finding the insulation defects make great effort for ensuring the reliability of the electrical equipment. Thus the performances, such as sensitivity and classification and recognition of PD pattern of PD detector need verified. This paper offers an effective tool to evaluate these performances of PD detectors. Design of the system consists of three modules, including PD pattern simulation module, PD pulse sequence generating module, and high voltage simulation module. Example of realization is also given in detail, which takes advantage of Tesla coil structure to generate programmable pulse sequence under the control of embedded system according to PD pattern. After that, the performance analysis of this proposed evaluation system is discussed, the performance evaluation system can simulate PD pulse sequence with controllability of pulse position distribution and randomness of amplitude in a range referring to PRPD pattern from database.

Driving and protection circuit is an important part of power electronics, which is related to safe and stable operation issues in the power electronics. The driving and protection circuit is designed for the cascaded H-bridge STATCOM in this paper. The circuit can realize flexible dead-time setting, operation status self-detection, fault priority protection and detailed fault status uploading. It can help to improve the reliability of STATCOM's operation. Finally, the proposed circuit is tested and analysed by power electronic simulation software PSPICE (Simulation Program with IC Emphasis) and a series of experiments. Further studies showed that the proposed circuit can realize drive and control the H-bridge circuit, meanwhile it also can realize fast processing faults and have advantage of high reliability.

Starting from the perspective of electric vehicle users, this paper analyzes the service needs of different users for charging electric vehicles and considers various objective conditions of electric vehicles: the remaining electric vehicles, the driving distance from the charging pile / station, the charging of electric vehicles Charging time, the location of the charging equipment, etc., gives several user selection strategies that minimize the energy loss of electric vehicles, minimize the time spent by electric vehicle users, and optimize the comprehensive cost of users. Through the theoretical analysis and experimental simulation results, the advantages and disadvantages of several user selection strategies are compared to provide users with a good charging service for electric vehicles, and at the same time, the optimal choice of charging options for users is realized, The service quality of the car is conducive to the promotion and sustainable development of electric vehicles and charging equipment.

Nowadays, China, as the largest market in the global elevator industry, has become a closely related vertical transportation tool. The intelligence, safety and reliability of elevators are becoming a common concern among the state, elevator manufacturers and users[1-3]. In recent years, due to the excessive reliance on traditional technology, the user has caused casualties in the actual use due to improper operation. However, the use of elevators causes many casualties, which can be avoided from a technical point of view. Therefore, in this paper, on the basis of the traditional Internet technology, increase the microprocessor technology, automatic sensing technology, remote control technology, speech recognition technology and the establishment of the elevator safety operation regulation system, put forward the concept of "intelligent elevator" system, this system in practice, will greatly facilitate People's Daily travel and improve the safety and reliability of the elevator, the elevator more intelligent, better service to the society.

With increasing penetration of distributed generation system and electric vehicles in the distribution network, new active power flow management and economic dispatch are required to cope with uncertainty and intermittence. An electric vehicle (EV) group management agency is introduced in this paper in the context of Chinese electricity market, considering the flexibility of EVs and distributed generations (DGs). An active distribution network (ADN) coordination optimal dispatch model is set up to minimize the generation cost of the distribution network and the charging cost of the electric vehicles in Matlab environment. An IEEE33-bus test system model with electric vehicle group is built up to improve electric vehicle charging and discharging management. The results verify the effectiveness of the proposed method on improving the satiability and safety of the system.

With the trend of increasing dimensions of collected power load data, the data dimension reduction and classification become essential pre-processing steps for data mining and further application. On the basis of adaptive piecewise aggregate approximation(APAA) and k-Shape algorithm, a novel method is proposed. In light of the fluctuation degree and shape characteristics of the original load profiles, the new load dataset with variable temple resolution replace the old one by APAA, and further k-Shape algorithm is adopted for lower dimension load profiles clustering. K-Shape algorithm cluster curves with distance SBD as similarity measurement and also a novel method to extract the representative centroids is mentioned. The experiment testifies that APAA-kShape algorithm has shorter calculating time, higher accuracy and represent better load patterns than other cluster algorithms.

Firstly, the limitations of the existing transformer harmonic models both at home and abroad are analyzed. Based on this, the influence of the skin effect and the proximity effect on the windings under harmonics conditions is considered. Based on the electromagnetic field principle, the paper analyses the distortion characteristics of winding resistance parameters, introduces the AC power group coefficient and establishes of winding harmonic loss model. Compared with the traditional engineering calculation method, we can see that the theoretical model proposed in this paper can improve the accuracy and make the transformer winding loss calculation more accurate, Therefore, the model has certain guiding value for engineering calculation.

The authors provide the development results of one channel of the digital multiframe recording system for the radiography of objects having large optical thicknesses. The recorder is created based on the modern CCD matrix and quick-acting unit that operates as an electron-optical shutter. Scintillators based on the monocrystal LYSO were used to transform the ionizing radiation into the visible spectrum. Spatio-time characteristics of the recording system were investigated in the laboratory; the system operability was also checked. It was shown that the recording system allows recording with time exposure ≥ 100 ns. The unit of the multiframe recording system was tested on the internal polygon of FSUE "RFNC-VNIIEF". Testing powering of the mobile cyclic accelerator (ironless pulsed betatron) was also performed. The X-ray patterns of the static test objects were obtained. The thickness of the X-rayed lead test object was ∼90 mm at 4 m from the target at 11% contrast. The value of a capacitive storage of the pulsed powering system of the betatron electromagnet was C = 900 µF. The dimension of the tantalum target was 6×6 mm; the full width of the output gamma pulse at half maximum in a single frame mode was ∼100 ns.

For many years, it has been difficult to measure the internal temperatures of gas insulated equipments in high voltage apparatuses. This paper presents a method of measuring the internal temperature of UHV DC Voltage measuring device, which uses the temperature sensor of fluorescent decay time optical fiber transmission as the instrument. The method could accurately measure the internal temperature when the device is running. The paper mostly expounds the selecting temperature sensor and arrangement mode of sensor and detailed test method. The test method could determine the internal temperature of UHV DC voltage measuring device, as the same time could also provide references for measuring the internal temperatures of gas insulated equipments in high voltage apparatuses.

Electric vehicle charging network develops rapidly, but now there is still lack of research about business value evaluation of electric vehicle charging network. This paper discusses the business value of electric vehicle charging network based on Internet of vehicles. By analyzing the business evaluation index, a three-dimensional value index system of the two business segments is set up from the aspects of economy, society and environmental benefits, which aimed at improving the business value of electric vehicle charging network.

The measuring accuracy of UHV DC voltage measuring device has a great relationship with the temperature. It is necessary to study the internal temperature distribution of the device to ensure that the operating device could meet the accuracy requirement in the temperature range. Firstly, the device dynamic thermal flow field is analyzed in this paper. The flow field model is established. Through analyzing the calculation model, the internal temperature distributions under different environment temperatures is obtained. And then, the internal temperature rise at the rated voltage is measured directly by experiment. And the validity of the model is verified by the experiment. This paper introduces the details of the method. By studying the internal temperature distribution of the device, the temperature range in which the device is running is gotten. Suitable resistive elements should be chosen during the design so as to meet the measuring accuracy of the device.

In order to ensure the safety of important buildings, the structural safety monitoring of buildings is indispensable. Compared with wired sensor network, wireless sensor network have the advantages of deployment flexibility, lower maintenance cost and higher monitoring accuracy. It has a better application prospect in the safety monitoring application of building structure. This paper studied the application of wireless sensor network in the safety monitoring of buildings by studying the application requirements in the safety monitoring of building structure in important buildings, proposed a routing algorithm to improve the network lifetime, and simulated the routing algorithm. The results show that the algorithm can effectively improve the network lifetime.

With the continuous development and perfection of the power market, the interests of the power system are gradually diversified, and the role of demand-side resources in the competitive market is being reconsidered. This paper briefly introduces three kinds of price demand response projects in European and American countries, sums up and compared the research status of the demand response of industrial users in the Western countries and China, aiming at providing research directions for the research of Chinese demand response.

With the increasing penetration of DG and electric vehicles in distribution network, ADN gradually takes the place of traditional distribution network, which also brings higher requirements to the configuration of distributed ESS; In this paper, we mainly discuss the problem of how to optimize the capacity of wind/photovoltaic/energy storage in ADN with high penetration of DG when the total power connected to the grid of DG is fixed, in order to realize the harmonization of the economic and stable operation in power grid. Firstly, the hybrid system is analysed, which demonstrated the feasibility and rationality of proposed scheme. Secondly, being in distributed network investors' shoes and considering the constraints of distributed network, DG and ESS, the wind/photovoltaic/energy storage capacity configuration bi-level optimization model is established with the objective function of maximum annual income and minimum fluctuation of DG output power. Then the genetic algorithm is used to solve this model. Finally, the experimental results of 33-bus system verify the effectiveness of the proposed method, and the influence of different penetration scenarios on the annual income of distributed network is also analysed to provide a new idea for the economic operation of ADN.

By real-time acquisition information of lithium titanate battery packs and single battery in the auxiliary battery system of rail vehicles, we have extracted the operating condition of the train auxiliary battery system, and emphatically established the battery float charging test under the influence of temperature, voltage and other factors. Then have analyzed the aging state information of the battery. Combined with the thermodynamic and dynamics characteristics of the power battery, established the law of change of the battery characteristic parameter with the battery float charge, and determined the recession mechanism of battery

The rod-rod air gap electric fields are perfectly symmetrical in all kinds of extremely inhomogeneous electric field while the maximum asymmetry exists in the rod-plane air gap electric field. Other types of uneven electric field air gap breakdown characteristics fit in between. The rod-plane air gap electric field is an important reference for the designing of insulation strength. In this paper, the impact tests of rod-plate air gap are carried out in the field environment of different altitudes. Discharge characteristic curves of switching and lightning impulse at different environmental factors were given. The increases of the 50% discharge voltage of the rod-plane air gap switching impulse and rod-plane air gap lightning impact are larger. The influence of altitude on rod-plane air gap lightning impact is tiny. Through the analysis of test results, the influence mechanism of environmental factors on the discharge characteristics is also discussed.