Table of contents

Preface

2018 International Conference on Advanced Technologies in Energy, Environmental and Electrical Engineering (AT3E 2018) was held in Shandong University(Qingdao), China from Oct. 26 to 28, 2018. AT3E 2018 is co-organized by International Society for Environmental Information Sciences (ISEIS), Shandong University, American University of Madaba and APISE, sponsored by South-South Collaborative and Sustainable Development Center, China International Center of Economy and Technology Exchange, United Nations Development Programme, Coco Cola Water Program. The conference provides a useful and wide platform both for display the latest research and for exchange of research results and thoughts in broad Energy, Environmental and Electrical Engineering. 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 achievement of the conference. This book covers 2 chapters: Chapter 1 Energy and Electrical Engineering and Chapter 2 Environmental Engineering.

List of Committies are available in this pdf.

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

The 500kV UPFC demonstration project of Jiangsu Suzhou south grid was put into operation in December 19, 2017. Depending on the State Grid science and technology project "Study on control and protect coordination of 500kV UPFC" and according to the system operation mode and equipment parameters provided by the relevant institutes, the authors had researched on electromagnetic transient modelling and simulation of 500kV Suzhou south grid and 500kV UPFC in earlier period. In this paper, the theoretical analysis and simulation verification of several typical faults in 500kV UPFC station are carried out by using the above model, which is an important part of the project.

Based on the port energy structure and transient energy function, this paper proposed the generator energy transfer function (GETF) of generator port to analysis power system transient stability issue. By calculating the energy transferred between generators, generator port energy and its changing rate, it can quickly identify the critical generator cluster in a short time after the fault cleared and assess transient stability of the power system, also take control measure. Finally, this method was verified through IEEE-140 node system and it proved the effectiveness of the method.

As multi-infeed HVDC systems are integrated into power grid, the operation characteristics of power grid have changed significantly. The problems of the shortage of dynamic reactive power reserve and voltage support need the allocation of dynamic reactive compensation device such as synchronous condenser urgently. This paper researches the influence of installing synchronous condenser on system performance in multi-infeed HVDC power grid. Based on the analysis of the defects of synchronous condenser on HVDC commutation failure under existing conventional control mode, this paper presents the emergency control strategy and system architecture with synchronous condenser. In the end, the effectiveness of the proposed control strategy is verified based on the actual grid simulation.

Nowadays, all nuclear power plants including constructed ones and those under construction are coastal plants in China. Water resources assessment of coastal nuclear power plants in China is based on the Guidelines for Water Resources Assessment of Construction Projects (SL 322). However, the specific guideline for water resources assessment of coastal nuclear power plant projects, the Guidelines for Water Resources Assessment of Coastal Nuclear Power Plant Projects, has not yet issued at present. According to the plans for intake, usage and discharge of water proposed by the owner of coastal nuclear power plants, it was proposed that the general requirements for water resources assessment by considering characteristics of intake, usage and discharge for water. In this study, Tianwan nuclear power plant was chose as the case study. Researches on yields of intake and usage of water, and the impact of water discharge for this nuclear power plant could provide the reference for water intake and usage rationalities, as well as the impact analysis caused by water discharge of coastal nuclear power plants.

The existing analysis methods for SVC fault location almost require the result of tests or lab fault simulation. That is too much time and too high cost. This paper proposed a novel rapid analysis method for SVC fault location without lab tests nor fault simulation. They can quickly identify SVC fault type, locate the fault source, improve the efficiency of fault analysis. Their validity and feasibility were verified by using the proposed methods to locate actual SVC fault.

A abnormal data repairing method based on adjacent power plant and integrated similar days of BP neural network is presented. Some factors influencing power generation such as geographical position, temperature and day type are considered. By means of selecting adjacent power plants with high power correlation to plant to be repaired by Pearson product-moment correlation coefficient and the combination of Grey Relational Analysis and curve similarity is used to select similar days. Finding out the integrated similar days' data of the adjacent power plant that is in conformity with the day to be repaired, corresponding BP neural network model is built, then the diverse learning speed algorithm are employed to repair abnormal data. The actual abnormal data in PV prediction power repairing results for Qinghai district show that the proposed method possesses better repairing accuracy.

Loop closing current may affect the security of power system during loop closing operation. In this study, practical criterion of secure loop closing operation is derived by analysing the relationship between current protection and loop closing current. On the basis of the practical criterion, a decision-making method for loop closing operation in 10kV distribution network considering the probability distribution of electric load is proposed. Based on probabilistic load flow theory, the cumulative distribution characteristic of loop closing current can be obtained by cumulant method. Finally, make a decision on loop closing operation according to the over-limit probability of loop closing current. In addition, a method for calculating cumulants of input variables based on historical load data is proposed, which overcomes the shortcomings of traditional numerical methods. The simulation results of a practical study case verify the effectiveness and practicability of the proposed method.

Partial discharge is one of the main causes of insulation condition assessment. Transient earth voltage (TEV) method is widely used in partial discharge detection of switchgear. This article simulated the actual fault defects in the switchgear. A TEV sensor was designed to measure the TEV signal generated by internal partial discharge. The amplitude and number of triggers of the TEV signal pulse were counted. A method for TEV amplitude-number chart was proposed. The similarities of spectra at different voltages were compared and the support vector machine (SVM) algorithm for verification was used. The results show that the matrix similarity comparison method and support vector machine algorithm can be used to analyze the amplitude-number chart of TEV pulse under different voltages. The partial discharge stage can be recognized by using TEV amplitude-number and the state of the switchgear can be predicted.

As the basic assistive device of substation equipment maintenance, the movable workshop in substation plays an important role to ensure the security of power system construction and the reliable operation of the substation equipment. In order to meet the actual needs of on-site maintenance of substation equipment, this paper designs a kind of movable and self-enlargement workshop, which has the characteristics of low cost, one-touch control, excellent insulation, easy operation as well as high security. The finite element model of the workshop is elaborated under the circumstance of wind, snow and other extreme condition; then the maximum displacement and ultimate stress of the workshop are calculated considering the extreme condition. The results indicate that the designed workshop greatly meets the security and reliability in substation under severe environment.

Due to the uncertainty of renewable energy and complex construction of distribution network, the wind-solar power integrated distribution network is one of the most difficult optimization problems in operational planning of power system. This paper proposes a risk-based credibility assessment (RbCA) model for stochastic distribution network planning (SDNP) with wind-solar power penetration to obtain the optimal planning from the perspective of risk aversion. In the proposed model, the uncertain wind power and solar power are designed as credibility interval variables, and the operation risk of SDNP is measured by the credibility assessment of wind-solar power. In addition, in consideration that the SDNP is a constrained non-convex and multi-modal optimization problem, and the particle swarm optimization (PSO) is easily trapped into premature convergence in dealing with this kind of problems, a dynamic PSO with escaping prey (DPSOEP) has been developed to increase the diversity of the population and then obtain the optimal planning of distribution network. Simulation results obtained based on the modified IEEE 33 nodes distribution system show that the proposed model and algorithm are reasonable and effectiveness in dealing with the SDNP with uncertain wind-solar power penetration, considering the integration of various inequality and equality constraints.

In order to improve the dynamic performance and robustness of permanent magnet synchronous motor (PMSM) servo system, the moment of inertia identification based on model reference adaptive algorithm is studied. According to the problem that the stability and convergence response speed of the model reference adaptive identification (MRAI) algorithm can not be combined at the same time, the particle swarm optimization (PSO) algorithm is used to optimize the model reference adaptive gain coefficient to realize the fast and stable identification of the moment of inertia. The simulation results showed that the method has strong optimization ability, fast convergence speed, small oscillation amplitude and good stability.

In this paper, the GTEM cell electric field using to UHF sensor calibration is simulated by HFSS software. According to the simulation results, the field uniformity of the total electric field strength in the "1/3 area" of the GTEM cell can meet the requirements before being placed in the UHF sensor. However, the field uniformity of the total electric field strength has been greatly changed after the UHF sensor is placed. In addition, the maximum amplitude of the field strength change in the UHF sensor test area exceeds 10 dB compared to that before the UHF sensor is placed. It has a great influence on the calibration accuracy of UHF sensors. Through the simulation study of the electric field of GTEM cell, it provides a reference for further improving the calibration accuracy of UHF sensor.

An internal over-voltage identification method based on atomic decomposition(AD) and Support Vector Machine(SVM) is proposed. Firstly, the three-phase voltages of bus are decomposed by AD algorithm to get the optimal atoms. According to the atom frequency, the optimal atoms are constructed as characteristic atom matrix, which can reflect the time-frequency characteristics of the over-voltage signal. Features are obtained from the characteristic atom matrix by singular value decomposition. Finally, the features are input into the SVM to achieve the identification of seven types of internal over-voltages. The proposed method is verified on the simulation platform. The results show that the proposed method has high accuracy.

10kV switchgear bus arc protection based on current lockout criterion has the disadvantage of insufficient sensitivity when single-phase fault occurred. This paper proposes a new type of 10kV switchgear arc protection on the basis of voltage lockout. The electrical characteristics of 10kV ungrounded systems of various short-circuit fault are analyzed by simulation calculation. Analysis results show that the new 10kV switchgear voltage lockout arc protection has a higher sensitivity than arc protection based on the current lockout.

This paper takes the output of the switched reluctance generator as the research object and analyzes the main factors affecting the output voltage ripple. In order to optimize the output voltage of the switched reluctance generator at high speed, This paper proposes an angle position control strategy based on improved fuzzy control. When the load changes, the initial value of the turn-on angle of the fuzzy control adjustment is adaptively identified. Adaptive value of turn-off angle input to the system. This method quickly and accurately changes the conduction angle so that the output voltage is optimized. The simulation results show that compared with the fuzzy control, the improved fuzzy control strategy can effectively optimize the output voltage and reduce the voltage ripple.

In actual operations, the surface insulation strength of metal oxide line arrester can be thus decreased due to inevitably dirt and icing, and the flashover voltage can be significantly reduced, which threatens the operation safety of the entire transmission line. Therefore, in this paper, the internal and external electric field and potential distribution of a 35kV line arrester under operating voltage are studied quantificationally. ANSYS and COMSOL finite-element software was used to calculate the field and potential distribution of the arresters under clean, polluted and icing condition. Based on the analysis of the electric field distribution, the main influence factors of the electric field and potential distribution as well as the equivalent calculation method under different environmental conditions of the arrester are obtained, which can give help to the design and application of line arresters under different environmental conditions.

A 3D Reynolds-averaged Navier-Stokes (RANS) model was refined in the paper based on the $k-\varepsilon -\bar{{v}^{\prime} {}^{{}^{2}}}-f$ turbulence model to simulate the drag reduction (DR) flow in the tube. The influence of elastic parameters on the drag reduction effect was studied using this numerical model and validated by the DNS data. The results showed that DR effect increased with both the relaxation time λ and the maximum extensibility of molecule L . DR effect had an upper limit with the increasing of the maximum extensibility of molecule L . and the growth of relaxation time λ also could enhance that upper limit.

In order to research the discharge properties of the direct carbon fuel cell (DCFC) with a molten metal anode, the experimental system with a reactor is designed and constructed. The reaction mechanisms at both anode and cathode are analyzed. The molten Sn and Sb are used as the anodic material for comparison. The cell performance of DCFC is tested before and after discharging in the battery mode and the carbon fuel mode, respectively. In the battery mode, due to the different states of metallic oxides, the current density is not degraded after discharging with the molten Sb anode, but sharply decreases with the molten Sn anode. On the contrary, the cell performance with Sb is much worse than that with Sn after discharging in the carbon fuel mode, which is result from the volatility of Sb together with the reduction of its oxide. The above studies will help to thoroughly understand the underlying mechanism of DCFC with a molten metal anode.

The existing AVC system uses the expected voltage value as the control command value of the continuous adjustable reactive power source. However, the phenomenon of "grabbing reactive power", which is caused by the difference in the adjustment speeds of various continuous adjustable reactive power sources, is not conductive to safe, economical and high-quality operation of the power grid. To solve this problem, a method of selecting AVC control command is proposed, in which the expected voltage value as control command is delivered to the continuous adjustable voltage source with high sensitivity and fast adjustment speed and the expected reactive power is delivered to the rest. This method, combined with the existing AVC system, forms an AVC control command selection system to effectively solve the problem of "grabbing reactive power" and ensure safe, economical and high-quality operation of the power grid.

Low-frequency oscillations occur frequently in many interconnected power grids around the world. In severe cases, even system-wide chain reactions are triggered, resulting in system unwinding and large-scale blackouts. In this paper, a FFT-based forced power oscillation disturbance source localization method is introduced. Using the active power and frequency of the steady-state oscillation phase of the low-frequency oscillation, the dominant component of the oscillation is obtained by the fast Fourier transform (FFT), and then the disturbance source is automatically positioned according to the energy function. Taking the low-frequency oscillation accident occurring in Hunan power grid as an example, the energy function based on FFT and the traditional energy function method are compared, which shows that the proposed method can locate the disturbance source more accurately.

The multi-interrupter SF6 circuit breakers are widely used in High Voltage Direct Current (HVDC) station. The AC filter circuit breakers play an important role on the reliability of the grid. In this paper, the voltage distribution of the multi-interrupter circuit breaker is researched and the regulation method is obtained. First, the equivalent model of four-interrupter SF6 circuit breaker is established. The equivalent circuit is composed of controlled post-arc sources, post arc resistors and equivalent capacitors. The equivalent capacitance and stray capacitance across each interrupter were calculated by using finite element analysis software (ANSYS). Then voltage distribution was simulated under the condition that different measures were adopted. The measures include paralleling resistance, capacitance and resistance-capacitance. Comprehensive comparison of various voltage-sharing measures, paralleling capacitance and resistance is suitable for multi-break SF6 circuit breaker at the present condition. At last, experimental system was built based on Weil synthesis circuit to seek suitable scheme. The test results verify the simulation analysis, which indicates that the grading resistance-capacitance is suitable voltage regulation method.

Electromagnetic Transients (EMT) simulation is an effective approach to study the dynamic behavior of complex AC/DC power grids. However, with increasing applications of the electronic equipment and the expansion of power grid, conventional EMT simulation tools are facing significant challenges with regard to simulation speed and scale. In order to improve the performance of EMT simulation, some approaches have been proposed. A time domain transformation methodology [1] has recently been proposed. In this paper, based on the large time step EMT algorithm, an electromagnetic transient simulation program has been developed and is used to study large scale power system dynamic behaviors. The result shows that the new EMT algorithm can not only guarantee the simulation accuracy, but also effectively improve the speed of full electromagnetic transient simulation of large scale complex power grids.

The comprehensive excavation face is the most seriously polluted place in the underground of coal mine. Using FLUENT software to simulate the influence of the diameter change of the suction air inlet of the extraction duct on the airflow field in the long pressure short draft ventilation system, the roadway in the comprehensive excavation was taken as the research object. From the simulation results, it can be seen that the diameter of the air intake directly affects the air flow distribution in the roadway, the change of the diameter of the suction nozzle will interfere with the inrush jet, Which has the greatest influence on the wind speed within the range of 0-10m from the excavation end. At the same time, it has obvious influence on the vortex in the roadway. When the diameter of the suction air outlet increases from 0.5m to 0.6m, the vortex area decreases, and when the diameter increases from 0.6m to 1.0m, the vortex area gradually expands.

As insulated gate bipolar transistors (IGBTs) become widely used in all kinds of power conversion systems, the demands of power converters to the IGBT's reliability turn to be more stringent. Thus, investigations of the IGBT's internal failure mechanism are very important to guarantee the improvements of device reliability and the optimizations of design and applications. Previous researches concentrate on the external factors of the device failures which are the failure modes. However, it lacks thorough studies of the internal mechanism which ultimately causes the device failure. In this paper, the analysis of the internal mechanism of thermal breakdown, has been presented based on the detailed investigations of the IGBT's structure and operation principles, applying the semiconductor physics theory. In addition, the existing misunderstandings on the IGBT's failure mechanism in the normal applications have been pointed out. Finally, experiments were designed to rebuild the failure process with the online monitoring through the high speed thermal infrared imager. This further verified the proposed conclusion and ascertained the internal failure mechanism of the IGBT chips.

In large-capacity power electronic devices, fully controlled power electronic devices, such as insulated gate bipolar transistors ( IGBT ), which are widely used at present, are the core components to realize high-performance power conversion and control. With the increasingly wide application of IGB, its voltage, current level and working junction temperature are getting higher and higher, and its working environment is also getting worse, putting more and more stringent requirements on reliability, and the reliability of power electronic devices has also become the most important factor determining the safe operation of the whole device. Therefore, finding out the internal mechanism of IGBT failure is an important guarantee for improving the reliability of device operation and realizing optimal design and application. The research that has been carried out mainly focuses on various external factors that cause failure, namely various failure modes of IGBT, and lacks in-depth research on the internal mechanism of final failure. On the basis of in-depth analysis of IGBT's structure and working principle, this paper analyzes the internal mechanism of IGBT's breakdown failure with semiconductor physics theory, finds out the fundamental principle of causing failure, and designs experiments to reproduce the occurrence of failure, thus further verifying the conclusion reached in the analysis.

The reliability and intelligence of intelligent disconnecting switches breaking-closing is one of the key technologies for intelligent substation construction. The tasks of substation operation and maintenance have increased greatly due to the increasing requirements of security operation level and service quality. Only to enhance the intelligent and automatic level of power grid, reliability of smart substation devices operation can be improved. The research condition of breaking-closing position monitoring technology for intelligent disconnecting switches at home and abroad is summarized and the methods are illustrated respectively from the views of their basic idea, characteristics, and disadvantages, including image recognition method, optical sensing method, pressure sensor method, auxiliary contact principle method, attitude sensor method, and so on. Finally, the research tendency in the intelligent disconnecting switches position monitoring field is point out.

The low-voltage distribution system is influenced by ever-increasing harmonics caused by nonlinear loads. A simple and reliable 24-pulse rectifier transformer for high-current and low-voltage is proposed in this paper. The proposed 24-pulse rectifier transformer consists of four secondary windings in which an original delta-extended connection is adopted. First, the existing 24-pulse rectifier system is analyzed. Second, the topology, the phase-shifting principle, the input current and the output voltage of 24-pulse transformer are described. Finally, the simulation results validate the theoretical analysis and the advantages of the new 24-pulse rectifier transformer in multi-pulse rectifier areas.

The motors of new energy vehicles adopt the built-in permanent magnet synchronous motor (PMSM) with high system efficiency. The mainstream control method of electric drive system is space vector PWM (SVPWM) algorithm. The SVPWM algorithm has higher low-order harmonic content in the low-speed segment voltage waveform, large asynchronous motor torque, and large motor iron loss, which makes the electric drive system less efficient in the low-speed segment system. This paper creatively proposes to change the modulation ratio M of the SVPWM waveform by adjusting the bus voltage, switching frequency and different control angles to reduce the harmonic content of the system to improve the overall efficiency of the electric drive system. In this paper, a theoretical model is established for the motor phase voltage harmonics, and various factors and components affecting the harmonic content are analyzed. Combined with the digital signal processor (DSP) based SVPWM vector control algorithm, the motor control SIMULINK simulation system is built. The voltage harmonic analysis of the simulation system is carried out by using the FFT tool in POWERGUI. The electric drive system bench is established for testing, the electric drive system simulation and the test bench test data are analyzed, and a clear method and means are proposed to reduce the harmonic content.

How to determine the insulation status of transformers reasonably which is very important for the life management of transformers. Electrical data, oil Chromatograph data and oil test data are important parameters for measuring the insulation state of transformer. In this paper, the relationship between electrical, chromatographic and oil test data and transformer operating years in production operation is analyzed by means of regression analysis and hypothesis testing. The results show that the relationship between the absorption ratio, oil breakdown voltage and hydrogen hydrocarbon content is very weak between the operation years of the transformer and the CO and CO₂ gas content is strictly related to the operation years of the transformer. The former mainly reflects the insulation performance of transformer oil, and can effectively identify the integral fault of transformer, but it cannot effectively reflect the residual life of transformer by the influence of filter oil and oil transfer. The latter reflects the state of transformer solid insulation and is an old characteristic of transformer life prediction. An example verifies the validity of the above conclusion.

Three-ratio method is one of the effective methods for latent fault diagnosis of power transformers, but there is a lack of code in this method. According to the DGA data collected in this paper, it is found that the variation trend of the characteristic gas in the same fault samples is the same, and the variation trend of different fault features is obviously different. In this paper, by excavate the changing trend of each data in DGA, using the grey relational theory and using the DGA fault identification method based on grey relational analysis, the fault diagnosis of code absence power transformers in DGA is carried out. It makes up for the deficiency of the three ratio method and improves the accuracy of transformer fault diagnosis. The research results have important theoretical value and practical value of engineering. It can be popularized vigorously and bring great economic benefits to the power system and the society.

With the rapid development of power grid, the equipment of power grid is more and more intensive, and the requirement of reliability is higher and higher. Oil-immersed transformer is one of the most critical equipment in power system. Its operation reliability is directly related to the safety and stability of the whole power grid. When transformer fault occurs, even under the same external operating environment, the hot spot temperature is different from the normal hot spot temperature. Generally, when the transformer overheat fault occurs, the hot spot temperature is usually higher than the normal hot spot temperature, and different fault modes will also cause different temperature variations of the transformer hot spot. By analyzing the variation law of the transformer hot spot temperature under different faults, it is helpful to evaluate and predict the load capacity of the transformer in real time and ensure the safety operation of the transformer. Hot spot temperature is a factor of measuring transformer performance, and it is also the most important limiting factor of transformer load capacity. It is also related to transformer safety and reliability, service life and manufacturing cost. Therefore, accurate calculation and prediction of the hot spot temperature has great significance for reasonable using transformer. Therefore, a support vector machine thermal calculation model based on gradient descent method is proposed in this paper. The validity and feasibility of the model are verified by the comparison of calculation and experiment results.

2,6-di-tert-butyl-p-cresol (T501) is the most commonly used antioxidant for insulating oils. It has been found that the amount of T501 added to the insulating oil affects the physical and electrical properties of the insulating oil. In this paper, the effects of antioxidants on insulating oils at different concentrations were studied. The research focused on acid value, water-soluble acid or alkali, flash point, kinematic viscosity, volume resistivity and interfacial tension. An aging test was conducted at 115°C to test changes in acid value, sludge, and volume resistivity. Add the same quality insulating paper to the oil sample with the blank oil and T501 added in the amount of 1% (mass fraction), and isolate the oxygen to the effect of furfural before and after the addition of the antioxidant after aging at 130 °C. The results show that with the increase of the amount of antioxidant T501, the interfacial tension, acid value and electrical resistivity will decrease its performance index, but the effect on flash point, viscosity and pour point is not obvious. The aging test by heating the open cup shows that the antioxidant has an obstructive effect on the acid value and the sludge, delays the aging of the insulating oil, but accelerates the aging hydrolysis of the insulating paper. Therefore, it is recommended that the antioxidant content in the insulating oil should not be excessively added. In the insulating oil, the proportion of the antioxidant in the insulating oil should be reduced on the premise that the oxidation resistance can be achieved, and the T501 part consumes the logistics.

In this paper, the structural characteristics of large synchronous condensers and the working principle of static frequency converter are studied firstly. Intermittent commutation and natural commutation are adopted by the inverter on the machine side in low-speed and high-speed stage respectively. Second, methods of sensorless control in different conditions are proposed. The initial rotor position is estimated through two methods, the terminal voltage method and the rotor-flux-oriented method. And similar methods are used in low-speed stage. Besides, phase-locked loop is used in high-speed. Finally, simulation models are established in PSCAD/EMDTC. The rotor-flux-oriented method used in standstill condition and low-speed stage shows better accuracy. And the phase-locked loop is also effective in high-speed stage. Therefore, the sensorless control methods are feasible.

This paper presents a comprehensive analysis of the Electric Vehicles (EVs) charging behaviour based on the data collected from the UK flagship demonstration project - Low Carbon London. Data of seventy residential charging facilities over one year are processed and analysed. The charging behaviour of the cluster of charging facilities and selected charging facilities are analyzed respectively. Based on the in-depth analysis, the potential of the EV charging facilities for joining the demand side management program are further investigated. To evaluate the performance of using charging facilities to join Demand Side Management (DSM) program, numerical analysis based on different DSM programs are presented.

Foamy oil phenomenon is of great significance for the exploitation of some heavy oil reservoirs. Many researchers have conducted a lot of research on foamy oil, but there is still no systematic research on why foamy oil phenomenon only appears in some special heavy oil reservoirs. Therefore, it is of great significance to study the formation of foamy oil in depth. This paper simulates the process of three kinds of heavy oil solution gas drive processes with different types of heavy oil under the formation conditions in an etched glass micromodel, and the flow characteristics of gas bubbles in the micromodel were observed. The results show that the location of gas bubbles nucleation was mainly distributed in the main channel and the rock surface of the micromodel. Compared with gas bubbles in the foamy oil, the dispersed gas bubbles in the conventional heavy oil had a shorter existence time and no obvious foamy oil phenomenon, the size of gas bubbles in the conventional heavy oil was larger, and the migration, growth and coalescence rate were faster.

The capacity, energy, internal resistance and open -circuit voltage are key indicators to represent the performance of lithium ion batteries. The battery rate characteristic refers to the battery charge and discharge performance; the higher rate battery can withstand higher discharge current. This paper researched the influencing factors for consistency performance of Lithium ion batteries which were tested at 1/3C, 1.5C and 2C charge and discharge. The result shows that the charge and discharge voltage of the series-connected cell group is different slightly, and the basic electric performance (capacity, internal resistance) is not affected basically when the charge rate is less than 1C, the temperature rises slightly when charging the series-connected cell group when the charge rate is larger (higher than 1C), and proposes a method for select the appropriate battery charge and discharge rate, to eliminate the adverse batteries and ensure the good performance of batteries.

The primary frequency modulation function of generating units is an important means to maintain the frequency stability of the power grid. The reasonable assessment criteria help to regulate the primary frequency modulation performance of generating units and enhance the enthusiasm of units to participate in frequency modulation auxiliary services. On the basis of mastering primary frequency modulation principle, the response characteristics of the electro-hydraulic governor and the turbine under frequency excursion are analysed in detail. Aiming at the shortcoming of the current primary frequency modulation evaluation standard, an integral electricity algorithm with different weights added according to the contribution of primary frequency modulation is proposed. Finally, based on the concrete example, the correctness and rationality of the improved method are verified.

Regional integrated energy system is a combination designed to connect various energy supply and demand systems based on the in-depth integration of urban regional energy and information communication. With the integrated energy system in a certain industrial park as research object, the paper aims to determine energy constitutions within the integrated energy system and various load curves, calculate operating economic interests and users' energy consumption cost of various subjects under an independent node, analyze cooperation modes of these subjects in cooperation situations, discuss specific economic returns of such subjects under different combination modes and compare theses combination modes, and rationally distribute the total returns of the integrated energy system by Shapley value method, based on which calculate the incremental economic benefits of various subjects.

The reasons of the no-action of conventional protection and arc protection based on current latching up criterion when phase-to-ground fault occurs in the internal of switchgear or external cable resulting in the increase of line voltage which causes switchgear ground discharging and damages with the further development of the fault are analysed in this paper based on the accidents of the 10-kV switchgear in the substation. Therefore, it is concluded that the switchgear should be tripped when single-phase grounding happens and accompanied by arc discharging. On the basis of it, a new type of 10-kV switchgear arc protection based on the principle of voltage latching up is proposed and compared with the arc protection based on the principle of the current latching up. The results demonstrate that the new voltage latching up arc protection has higher sensitivity than arc protection based on the conventional principle of the current latching up in the 10-kV switchgear.

Aiming at the ever-increasing trend of distributed energy resources (DER), this paper proposes a home/community integrated energy management model based on electric energy routers (EER). Firstly, based on the modeling of energy storage and controllable load in home energy Local Area Network (LAN), a home-level collaborative scheduling model is proposed. Then, considering the power interaction between homes, a community dispatching model is established to minimize the electricity charge and improve the utilization ratio of renewable energy. Cplex18.0 is used to solve the daily optimal electricity plan. Finally, the results of the case study verify the effectiveness and economy of the proposed model by comparing community's cost under different modes.

Uncertainties from distributed generations (DGs) make conventional reactive power optimization (RPO) methods difficult to be applied in the distribution network (DN). To settle this issue, a novel two-stage RPO strategy for active distribution network (ADN) based on extreme scenarios is proposed in this paper. Random variables are handled through extreme scenarios, then flexible and inflexible variables are decided in two different stages to adapt to DG's randomness. Firstly, based on second order cone relaxation (SOCR), power flow equations are convexly relaxed to transform original model into mixed integer second order cone programming (MISOCP). Then, extreme scenario method (ESM) is employed to determine DG's deployment. Finally, numerical tests are performed on a modified IEEE 33-bus DN to demonstrate the effectiveness and feasibility of the proposed strategy.

Currently, the bipolar VSC-MTDC has become increasingly popular in practical projects. With the traditional wiring mode, line overload, generator tripping or load shedding may occur if a DC line or converter quits operation. While with a more flexible bipolar wiring mode, power shifting from the faulty network to the healthy one is permitted under same conditions. This paper proposes an active power shifting strategy based on bipolar VSC-MTDC. Since the positive-pole and negative-pole networks can be controlled independently, the transmitted power of the healthy pole network can be increased and that of the faulty pole network can be decreased, which is to avoid power surplus under abnormal operation conditions. This strategy has improved the reliability and transmission capacity of VSC-MTDC system. Then a 4-terminal MTDC simulation is established in PSCAD/EMTDC. The validity of the proposed strategy has been proved by the simulation results.

With the developing of voltage source converter based multi-terminal dc transmission (VSC-MTDC) technology, DC grid of meshed topology is the trend of VSC-MTDC; moreover, it will be widely used for large scale renewable energy integration. For DC grid of meshed topology, the control aspect is of great importance, while the randomness and volatility of renewable energy will affect the stability of DC grid. The control stability of the VSC-MTDC, especially the control of DC voltage, will face new challenges. This paper focus on the developing trend of VSC-MTDC, the control requirements of DC grid of meshed topology and the effects of large scale renewable energy to the VSC-MTDC are analysed. And mainstream coordinating control strategies under the new situation are compared through the way of theoretical analysis. Simulations based on PSCAD/EMTDC are carried out in a five-terminal meshed VSC-MTDC system with an isolated wind farm, a passive network and three ac synchronized power grids, proving the accuracy of theoretical analysis. Then control characteristics and applicability of the coordinating control strategies for meshed VSC-MTDC with large scale renewable energy integration are concluded.

With the integration of large clusters of variable renewable energy, plus the fact that modern power system has appeared great varieties of complicated characteristics. Improvement of safe and stable operation of the grid system has become a research focus in the new situation. Such being the case, a critical node identification method based on the theil entropy theory is proposed. By studying the characteristics of power flow and voltage variation, new methods for system safe operation improvement are explored. Firstly, proceeding from the mechanism of load variation on voltage and power flow, the theil entropy index of voltage growth rate is established to describe the equilibrium of voltage variety and the theil entropy index of weighted flow impact rate to describe the uniformity of power flow variation. Secondly, considering both subjective preferences and objective data, binary feature analysis and entropy weight method are combined to get the comprehensive index which can accurately identify the critical nodes for power grid, At last, the simulation results of IEEE30 node system and a southwest certain area power net-work has verified the validity and efficiency of the model. Further more, evaluation results has provided a reference for the construction of security defense system in modern power system.

Under the pressure of power system reform, it is of great significance to study a system and scientific evaluation model of grid development and production management (GDPM) status for effective supervision and competition promotion. Firstly, a hierarchical analysis of indices is incorporated in the overall objective, the criteria layer, and the indicator layer. The "input-output" indicators under each criterion are used to characterize the GDPM level of the distribution enterprises (DE). Secondly, the fuzzy analytic hierarchy process (FAHP) and cluster analysis is adopted in the criteria layer to construct a combined weight judgment model. Then, for the indicators below each criteria layer, the data development cross-analysis (DECA) method is used to calculate the efficiency evaluation value corresponding to each criterion. Finally, the information entropy and the time degree theory are introduced to construct the dynamic weight vector for establishing the dynamic yardstick evaluation model. Taking county DE as the research objects, the research results provide a scientific and accurate management reference for supervisors as well as managers of power enterprises for decision making, which verifies the versatility and practicability of the proposed method.

Power system voltage regulator (PSVR) is a kind of high-voltage side bus voltage control method, which maintains the high-voltage side bus voltage of the power plant at a high level, increases the reactive power limit of the generator, and improves the voltage stability of the power system. In this paper, a PSVR model with gain reduction is introduced. With PCS- 9410 excitation regulator, the semi-physical simulation system is constituted on RTDS. By setting a three-phase ground short-circuit on the high-voltage side transmission line, the time domain dynamic response of automatic voltage regulator (AVR) and PSVR is compared and analyzed in synchronous generator and synchronous condenser mode respectively, simulation results show that PSVR with gain reduction can increase the reactive power response speed of the excitation system in two modes.

Compared to conventional units, the inherent stochastic nature of wind power requires additional flexibility during power system operation. It is necessary to analyze the characteristics of wind power fluctuations. Based on the investigation of the actual operating data of province, this paper presents a comprehensive analysis of the wind power output characteristics from different dimensions, including daily output characteristics, seasonal output characteristics and probability distribution of wind power output. The research results could be available to predominate wind power operation characteristics for the planning and scheduling of the power grid. Analysis shows that the relevance between the output of wind power and the time is weak. And the fluctuation of hour-scale wind power is large, while summation of the outputs from different wind farms regional apart could effectively decrease the fluctuation of wind power. The peak-valley difference also will be increased after the wind farms are connected.

Fire risk assessment is an important part of fire science and system safety engineering. "FRAME" means Fire Risk Assessment Method for Engineering. It is a widely used and comprehensive building fire risk assessment method based on a fixed index system, and compared with other methods, FRAME method can avoid artificial subjective influence, and it is more convincing. The paper discusses the advantages and calculation methods of FRAME, and takes a commercial building in Shijiazhuang as an example. By using the method, the fire risk of the building is evaluated and the strengthened fire protection measures are proposed based on the method.

An experimental model is established by simulating SVE to collect the contaminated soil samples near the wells of Dongying Dongxin oil production plant in Shandong Province as a polluted medium, ethanol, n-propanol, n-butanol as the target pollutant, the controlling variable method and gas chromatographic technique were used to investigate the effect of volatile pollutant species on the removal efficiency of SVE, found that for a single pollutant system, under the same SVE conditions, the removal rate of ethanol after 48h was up to 91.6%, n-propanol 73.5%, n-butanol 66.1%; under the same SVE conditions, the removal rate of ethanol after 48h was up to 88%, n-propanol 78% in the ethanol-n-propanol system, ethanol 84.1%, and n-propanol 64.9% in the ethanol-n-butanol system. It provides a basic reference for the remediation of contaminated soil in the field.

As a lignocellulosic biomass, wild colocasia can be efficiently hydrolyzed into reducing sugar after a certain degree of pretreatment. It is a high-quality raw material for the development and utilization of biomass energy such as fuel ethanol. The three factors of concentration, temperature, time, and solid-liquid ratio were selected as the three-level orthogonal experiment. The effects of acid-base pretreatment on the reduction of sugar in the wild carp were studied. The cell wall of the wild carp was treated by electron microscopy before and after pretreatment. The change. The experimental results show that the cell wall of the wild colocasia is thinner, the pores become larger, and the contact area is increased. The effect of acid pretreatment on the reduction of sugar by the wild colocasia is better than that of alkali pretreatment. When the acid concentration is 0.5% and the temperature is 100°C and solid-liquid ratio is 1:40, and the treatment time is 90min, the concentration of reducing sugar produced is up to 67.32mg/g.

The article describes the importance of microwave digestion system in many different scientific fields, and proposes a calibration method for lack of calibration specification in China. The method focuses on temperature, pressure and output power. It defines their measuring points, technical requirements. An experiment is carried out to calibrate the output power with its expanded measurement uncertainty. The calibration method can be referenced in daily calibration service of such apparatus.

Atmospheric non-methane hydrocarbons were measured continuously for one month in east urban area of Jinan in September, 2017. A total of 46 kinds of non-methane hydrocarbons were determined, and studies were performed on their concentration level, diurnal variations, chemical reactivities, and sources as well. The results showed that the total non-methane hydrocarbons concentration was 15.44 ppbv, among them alkanes, alkenes, aromatic hydrocarbons, and acetylene were the major components and their concentration also ranked by this order. The diurnal variation showed bimodal trend and two peaks appeared at 7:00-10:00 and 19:00-21:00, respectively, while the lowest value appeared at 14:00-16:00. Non-vehicle emission sources contributed 86%, 15% and 62.5% to ethylene, methylbenzene and xylene, respectively. Alkenes had higher atmospheric chemical activity and contributed the most to L^OH and OFP and the second most contributors were aromatics and alkanes, while the contribution from acetylene was almost zero.

With global warming, it is having a significant impact on the variation of precipitation and temperature. Both of them bring extreme discomfort to human's life and social development. The city of Xingtai in China, have suffered from many high temperatures and floods, which are resulted from climate change. Therefore, the purpose of this paper is to study the influence of climate change (precipitation and temperature) on water resources in Xingtai city by using the Statistical Downscaling Model (SDSM). SDSM is a coupled downscaling method based on multivariate regression and weather generator, which can effectively solve the spatial scale mismatch problem of small-scale hydrological response and large-scale climate information. Compared with other statistical methods, SDSM can be operated more simply and easily, and its results would be much better. The results show that: (1) the performances of calibration SDSM model are basically acceptable; (2) SDSM can better simulate the trend of precipitation and temperature; (3) The determination coefficients (R²) of measured and simulated values about minimum temperature, maximum temperature, average temperature and precipitation in the verification period can be above 95%, 94%, 93% and 64% respectively.

In order to study the influence of shape of cross section on hydrodynamics of gas-solid fluidization in the fluidized bed, five fluidized beds with the shapes of cross sections of circle, regular hexagon, square, rectangle and regular triangle were proposed. The fluidization characteristics and pressure drops in the fluidized beds with different shapes of cross sections were numerically investigated by Computational Particle-Fluid Dynamics (CPFD) models. The simulation results show that the shapes of cross sections affect strongly the particles distributions and the fluidized gas distributions due to strong wall effects, but affect slightly the pressure distributions and the pressure drops in the fluidized beds.

In the bivariate hydrologic correlation analysis framework, the correlation analysis between rainfall and runoff in Xiangxi River is constructed using Archimedean Copula method. Results show that: (1) the monthly rainfall and runoff in Xiangxi River water shed has a relatively strong positive correlation based on Kendall and Spearman's rank correlation coefficients; (2) the Frank Copula can be able to model the joint distributions of monthly rainfall and runoff according to goodness-of-fit statistic test. The obtained joint distribution can be used to simulate streamflows of Xiangxi River watershed according to the historical and predicted rainfall data, which can provide a basis for watershed water resources development.

A method of detecting dimethylamine (DMA) and diethylamine (DEA) was developed by HPLC with pre-column derivatization and fluorescence detection in this paper. Two fluorescent derivatization reagents were chosed to used in the method including o-phthalaldehyde (OPA) and 7-chlore-4-nitrobenzo-2-oax-1,3-diazole (NBD-Cl). Aliphatic amines in the natural water were labeled in two steps, the water samples were firstly reacted with OPA to eliminate aliphatic primary amines interferences, and then NBD-Cl could be used to selective detection of secondary amines, including dimethylamine and diethylamine. The detection limits of the method were 0.1 nmol/L and 10 nmol/L for DMA and DEA. Both of the linear ranges were 0.0005-0.1mol/mL with correlation coefficients above 0.9978 and 0.9988. This method is repeatable, sensitive and accurate for the detection of DMA and DEA in natural water samples.

With the acceleration of urbanization in China, the demand for water is increasing, and the consequent problem of drinking water safety is attracting more and more attention. This experiment is aim to learn about the water quality in Xiamen, and the water quality of water resources, the waterworks and users were collected and analyzed. The results showed that the water quality of water sources is reach to class II of the national water quality standards. The chromaticity, turbidity, conductivity, residual chlorine and bacterial colony of the water from both the waterworks and users were lower than the national standard. The total number of E. coli, cadmium and lead were not detected in domestic water in Jimei district. Based on the analysis of the water quality from the waterworks and the users, it may deduce that the pipe material in this area met the relevant requirements and did not cause secondary pollution.

In recent years, the ecological environment of the Yangtze River Basin has become increasingly prominent, and the sustainable development of regional economy, society and environment is facing severe challenges. As an important means to alleviate the contradiction between environment and economic development, the ecological compensation mechanism is an important link in the ecological protection of the Yangtze River Economic Belt. Therefore, doing a good job of cross-border ecological compensation in the Yangtze River Basin is of great significance to the construction of the Yangtze River Economic Belt. Many foreign countries, such as the European Union countries, the United States and Australia, have extensively established and implemented the basin ecological compensation mechanism, which has achieved good results in practice, and its experience is worth to learn. In view of the transboundary characteristics of the Yangtze River Basin, through the combing of the three major river basin profiles, management models and ecological compensation related practices, the article summarizes the ecological compensation models of three international transboundary basins by comparing the three typical transboundary basins (Rhine River Basin, Tennessee River Basin, Murray-Darling River Basin). The experience of ecological compensation promotes the establishment and implementation of the ecological compensation mechanism in the Yangtze River Basin.