Abstract:Aiming at the problems with low-safety and poor-autonomy existing in the large-scale electric vehicles(EV) during charging transaction, the EV charging transaction model based on blockchain technology is proposed. Under the competition mechanism of "multi-seller and multi-buyer" in power market, the commodity attributes of electricity are restored and the right of users to negotiate pricing is opened by utilizing the characteristics of blockchain technology for decentralization and high security. Firstly, EV charging transaction framework based on the blockchain architecture is established. And then, based on the similar network topology between the blockchain platform and the electricity market, EV charging transaction model under the blockchain architecture is established. Finally, comparatively analyze the charging schemes that meet the requirements of electric vehicle aggregators in the traditional electricity market and the electricity trading market under the blockchain platform. The results of calculation examples prove that the model established can meet the individual claims of electric vehicle aggregators, increase the revenue of new energy power plants, reduce carbon emissions, and provide a new idea for the electric vehicle charging trading market.

Abstract:With the development of energy Internet and 5G communication technology, the scale of power IoT is increasing, and there is a lack of effective authentication means for cross domain data exchange. The requirements of power IoT terminal cross domain authentication are analyzed and the side chain technology and its implementation mechanism in the cross chain technology of blockchain are discussed. Then, a cross domain authentication scheme of power IoT based on side chain technology is proposed. Firstly, the cross chain authentication architecture based on side chain technology is established, and the block data structure and two-way peg authentication information transfer model are designed. The authentication credentials are generated by public key certificate and digital signature, and the timeliness of authentication information is ensured by time stamp. Then, the cross domain authentication process of power IoT terminal based on side chain technology is proposed, which realizes the authentication certificate from application domain to authentication trusted delivery of the domain. Through the interaction and sharing of main chain and side chain data, the authentication scheme has the characteristics of cross domain effective, tamper proof and distributed consensus. Finally, simulation experiments are carried out in the application scenarios of distribution automation system to verify the feasibility of the scheme.

Abstract:With the development of the power internet of things, the distribution network is facing great challenges. As the end of the power system, it directly faces a large number of actual power users, and its customer experience satisfaction and power supply operation reliability have attracted much attention. In LoRa Wide Area Network(LoraWAN), a LoRa gateway based optimization algorithm is proposed for wireless relay, which is associated with HDAF to reduce the signal error transmission and power consumption as the nodes speed increases. In this strategy, gateway is treatedas relay and the distance of the employed nodes is manipulated by symbol error rate(SER), and the transmission power of all nodes is minimized according to the extreme conditionsof Karush-Kuhn-Tucker(KKT). Numerical results show that the SER can be effectively reduced compared with the forward strategies of amplify-and-forward(AF) and decode-and-forward(DF). Moreover, the power consumption of the communication networkemploying our proposed strategy will be less than AF and DF in the distribution network.

Abstract:The user side has a large number of load resources. The load has uneven capacity, scattered distribution, strong response potential and the ability to participate in grid regulation. Based on the difference in characteristics of power and current during load operation, a fingerprint database of load characteristics is established, and a non-invasive low-voltage load composition identification method for residential appliances based on a multivariate Gaussian model is proposed to achieve online decomposition of residential energy use. Based on the similar characteristics of similar electrical appliances, after obtaining the load actions and interruptible types of the bottom residents, an online aggregation monitoring method for the load demand response capability of the platform area from the bottom to the top is proposed. The REDD data set and the topology of a certain station area are used to test. The results show that the method has a better recognition of the residential load, and can better monitor the capacity of load resources participating in demand response. The method explores a way for participating in the intelligent utilization of system peak shaving and frequency modulation.

Abstract:With the development of modern computer technology and internet, the problem of information security has become more and more obvious. Because of the simple network environment in the early times, the traditional power quality terminal is not considered the information security issues, and is weak in resisting illegal access and network attacks. In view of the design defects of traditional power quality terminals, a terminal design and implementation scheme based on information security is proposed. Also, a practical solutions in access authorization, audit record, data integrity and tamper-proof modification, network attack, backup and recovery, and source code security are provided in the scheme. The information security strength of terminal is enhanced effectively. The security test results show that the scheme effectively enhances the terminal information security capability and resists network attack and other risks. The implementation scheme proposed can also be applied to protection relay, bay control unit, PMU, wave recorder and bay layer terminals.

Abstract:Modern power grids are facing grand operational challenges due to highly intermittent and uncertain renewable energies as well as new types of loads, etc. In recent years, the rapid development of artificial intelligence (AI) technology has brought up new solutions for optimal control problems with high dimension, high nonlinearity and high dynamics. Based on deep reinforcement learning (DRL), a novel autonomous control platform is presented, which can realize online learning and decision making for power system dispatch and control. The target of the proposed control platform is to transform massive real-time measurements directly into control decisions within sub-second. In order to fully demonstrate the feasibility of the "grid mind", autonomous voltage control and line flow control are taken as two examples to formulate the methodology of DRL-based power system dispatch and control problem. Finally, both deep-Q-network and deep deterministic policy gradient algorithms are applied to demonstrate the strong learning capability of DRL agents and their effectiveness through extensive simulation results.

Abstract:The research on fault location of overhead line and power cable is reviewed. Firstly the special problems in fault location of hybrid transmission lines are analyzed, and then the research status of fault location methods for hybrid transmission lines is summarized. The existing methods of fault location for hybrid transmission lines mainly include fault analysis, traveling wave method, frequency analysis and intelligent method. Among them, the accuracy of fault analysis method and traveling wave method is mainly affected by the uneven parameters of the hybrid transmission line. For frequency method, whether the natural frequency of fault transient signal can be determined accurately directly affects the fault location accuracy of spectrum analysis. The offline training of the sample set and the storage of a large amount of data is required for the intelligent method. Finally, the future research work is prospected.

Abstract:On August 14 and 15, 2020, rotating outages occurred in California power grid in the United States, affecting approximately 810, 000 people. The rotating outages is summarized and analyzed to provide reference for the safe and stable operation of China power grid. Firstly, the cutting load and rotating outage events caused by the extreme high temperature weather is introduced and the main causes of the rotating outages is summarized. Secondly, according to the actual situation of California power grid, the short-term and long-term countermeasures presented by the relevant institutions of California for this accident are given. Finally, combined with the problems exposed by the rotating outages, the enlightenment to China power grid is summarized from three aspects. Firstly, in the planning and operation of the power grid, more attention should be paid to the variation characteristics of net power load curve in the rapid development of new energy in the province. At the same time, a power planning mechanism that considers the influence of extreme situations should be established. Secondly, the power market construction should be optimized. Thirdly, the flexible control measures and capability of power grid should be improved.

Abstract:Various forms of new energy, a large number of power electronic users are more and more connected to the distribution network, which is the irresistible development trend of distribution network. It leads to more and more reactive, active and harmonic components in the single-phase grounding fault current. The passive arc-suppression technology with arc-suppression coil still has the problem of large reactive component, active component and harmonic component in the single-phase grounding fault residual current. The active arc-suppression technology with active intervention by external injection is an effective way to solve such problems. The research status of active arc-suppression technology for single-phase grounding fault in distribution network is summarized. The structure and control algorithm of active arc-suppression device are mainly described. Firstly, the hardware structure of arc-suppression device is analyzed from the aspects of cost, advantages and disadvantages, connection mode, etc. Secondly, the advantages and disadvantages of voltage arc-suppression algorithm, current arc-suppression algorithm and comprehensive arc-suppression algorithm are compared. Finally, the hardware structure and control algorithm of active arc-suppression technology are prospected, the possible problems and possible research directions are given.

Abstract:The establishment of a global energy Internet is an important development direction for large-scale development of new energy and a high proportion of access to the grid. The feasibility and influence of the VSC-HVDC grid across the European AC system is analyzed in this paper. Firstly, the distribution of resource loads in Europe is sorted out, the location and the capacity of the DC converter stations is designed, and DC grid structure is built. Then, based on the electromechanical transient simulation software PSS/E, 51 terminals VSC-HVDC grid is built on the European AC grid. Finally, the stability of the AC grid and the response characteristics of DC grid under multiple scenarios are studied. The simulation results show that the planned VSC-HVDC grid can provide power support, reduce the impact of power fluctuations injected by the converter station, and improve the stability of the European power grid.

Abstract:With the increasing complexity of integrated load structure of power grid, the diversity and volatility of the load increase significantly. Higher generalization ability and accuracy are required for the prediction model. However, the traditional algorithms have inherent defects such as easy overfitting and low accuracy, making it difficult to achieve accurate peak load forecasting under complex grids. To solve above problems, Bayesian optimized XGBoost model for short-term peak load forecasting is proposed. Firstly, the important features are screened through feature importance score to ensure better mapping relationship between input and output. Then, Bayesian optimization algorithm is introduced to determine the hyper-parameters to ensure the best state performance of XGBoost. Effectiveness of the proposed model is verified using power load data of a certain city in China. The results show that Bayesian optimized XGBoost has higher prediction accuracy compared with other machine learning methods.

Abstract:When a unipolar fault occurs on the direct current(DC) side, the DC current of the non-fault pole increases which is caused by the fault pole. In severe cases, commutation failure of the non-fault pole can be caused. When the DC current increases, the existing area-minimum(AMIN) control cannot start an effective emergency trigger at the first time to avoid commutation failure. For the question that the existing strategy cannot accurately calculate real-time commutation margin area, based on theoretical derivation of the existing strategy, the influencing factors that do not achieve the expected effect are analyzed. Then, according to analysis results, improved AMIN control strategy considering DC current change, electric sampling delay compensation and predictive control during commutation is proposed. Finally, based on the PSCAD/EMTDC model which is consistent with actual control and protection procedures, the improved strategy is tested and analyzed. The test results show that the improved strategy can effectively avoid non-fault pole commutation failure caused by the single-pole fault on DC side.

Abstract:For integrated energy systems that couple multiple forms of energy such as electricity, gas, coldand heat. Integrated demand response(IDR) of demand-side resources such as flexible loads, energy storage, and electric vehicles is conducive to tapping the response potential of multi-energy loads, stimulating integrated energy flexibility of the system and improving energy efficiency. Firstly, based on the regional electric-gas integrated energy system, a park-level cold-heat-electric-gas integrated energy system is constructed. Then, an integrated energy system scheduling model is established. The node energy balance equation is used to analyze the node energy price and clarify the dispatch-energy price-integrated demand response transfer relationship of the system. Based on the nodal energy price, the IDR model considering flexible loads, energy storage and electric vehicles as participants is established. Finally, the flexible load, energy storage, and electric power are analyzed through examples. The response of the electric vehicle is analyzed based on the energy prices of the nodes, and the load curves before and after IDR of the multi-energy users in different locations are analyzed. Ther analysis shows that while improving user utility, making full use of flexible load characteristics can effectively reduce operating costs.

Abstract:With the widespread application of energy storage power stations in the power grid, due to the energy relocation of energy storage power stations, the impact of large-scale energy storage power stations on the power purchase characteristics of the power grid is becoming increasingly important. The production simulation program based on mathematical optimization is adopted to study the demand for electricity purchase and the power grid operation condition considering the start and stop of the unit, hydropower cross-week adjustment, pumping and storage cross-day adjustment, solar thermal power station cross-day adjustment. The influence of the power purchase curve mode on the amount of purchased electricity is studied, and the external power purchase mode is determined. Then the impact of the energy storage power station on external power purchase mode is analyzed. The simulation results of an actual power grid in northwest China show that compared with the straight-line power purchase mode, the step power purchase mode can reduce the amount of purchased electricity and new energy abandonment rate, but the maximum power purchase is increased. On the basis of the step power purchase mode, the construction of an energy storage power station can further reduce the amount of external purchased electricity, new energy abandonment rate and the maximum purchased power. It is recommended to adopt step power purchase mode and a 1 200 MW energy storage power station. The research results can provide references for the construction of grid-side energy storage station in high proportion of new energy systems in China.

Abstract:The current research work is mainly based on the decomposition of the total load of the family house into the electrical level load, and less research on the bus load of the high voltage level. To solve this problem, ia bus load composition decomposition algorithm based on bi-directional long short-term memory(Bi-LSTM) is proposed. Firstly, Bi-LSTM is constructed on the basis of LSTM. Secondly, bus load and its corresponding external information sources (such as date type, weather, et al) are used as input of Bi-LSTM after training. Finally, taking the mean relative error between the predicted value and the target value of the building power load decomposed by the network as the evaluation index. The experimental results show that the method can effectively identify the bus load with unknown components. Compared with the traditional recurrent neural network and long-term and short-term memory network, the proposed algorithm has better identification ability.

Abstract:Non-intrusive terminal overcomes the problems of high cost, complex installation and inconvenient maintenance of the traditional intrusive terminal, and is widely used. However, the non intrusive terminal load identification ability is only evaluated by electricity index, and the evaluation system is single presenly. Therefore, multi-dimensional indicators are selected to comprehensively measure the terminal's ability to identify electrical loads, and a hierarchical multi group evaluation model of non-intrusive terminals is construct based on it. Entropy weight and analytic hierarchy process(AHP) combination evaluation technology is used to get the combination weight of indicators. On this basis, by using the grey technique for order preference by similarity to an ideal solution(TOPSIS) evaluation method, the electric appliance identification ability of the electric appliance combination cases are classified and sorted, so as to objectively obtain the overall identification ability level of the terminal and the quality of the terminal identification ability in different cases. Finally, four typical electrical appliances are selected from the non intrusive terminal demonstration platform of Jiangsu Electric Power Research Institute to verify that the scheme solves the problem of incomplete evaluation index data. Combined with the terminal identification ability verification of practical projects, the scientificity and effectiveness of the non-invasive load identification terminal identification ability evaluation are improved.

Abstract:To solve the problem of voltage distortion and unbalance caused by non-linear and unbalanced load, several inverters connected in parallel to micro-grid bus are used to control the bus quality. Taking a single inverter as an example, the causes of the output voltage quality degradation caused by the nonlinear unbalanced mixed load are analyzed. A master-slave control strategy is proposed, in which the master inverter acts as the voltage source and the slave inverter acts as the current source. The remaining available capacity of the slave inverter is used to compensate the harmonic and negative sequence current of the load, while the fundamental current and zero sequence current of the load are shared by the master-slave inverter. The control strategy effectively reduces the distortion rate and unbalance degree of the output voltage of the inverter, and embeds the power quality control function into the slave inverter, which avoids adding additional power quality control devices and reduces the system cost. Finally, the effectiveness and feasibility of the proposed control strategy are verified by building a simulation model in PSCAD environment.

Abstract:Gas insulated metal enclosed transmission line(GIL) is alternative to cable and overhead line because of its large transmission capacity, small floor space and low transmission loss. Metal particles of GIL will take off under electric field, which threatens the insulation performance of GIL. To better collecting metal particles, it is necessary to investigate the force analysis and motion characteristic of metal particles of GIL. Firstly, the force and motion characteristic of metal particles between coaxial cylinder electrodes is analyzed, under the condition that the influence of the basin-type insulators on the axial electric field strength is ignored. The resonant frequency of metal particles is used to characterize the activity of metal particles under DC voltage, and the influences of voltage and particle radius on the resonant frequency of metal particles are analyzed. Then, considering the influence of the basin-type insulator on the axial electric field intensity of GIL, several typical motion trajectories of metal particles are obtained. Finally, some suggestions for the layout of particle traps are given. The results show that it is necessary to arrange metal particle traps under the convex side of basin-type insulator.

Abstract:Insulated operating sticks are important operating tools in live work. Whether they are in good insulation state is of great significance to ensure the safety of live working personnel and equipment. Typical defects of insulated hot stick are detected by different measurement methods, and the effectiveness of the high-resistance defect detection is verified by the dielectric spectrum and creeping discharge characteristic tests. The results show that in the environment of temperature 25 ℃ and relative humidity 68.1%, the surface insulation resistance value of the insulated hot stick in the wet state is 60.1% lower than that in the dry state. The dielectric loss factor of the insulated hot stick in the dry state is less than 0.01. Use graphite to simulate the effect of different carbonization positions on creeping discharge voltage. It is obtained through creeping discharge test that when there is a penetrating defect in the two electrodes, creeping discharge voltage drops severely. Based on the research results, method of evaluating the insulation performance of an operating stick based on its surface resistance or dielectric loss characteristics has important engineering application value.

Abstract:Gas insulation switcher(GIS) is important equipment in power system. It plays an important role in the power transmission, and is of great significance to the safe and stable operation of the power system. The method of detecting mechanical faults using sweeping frequency characteristics of power equipment has attracted wide attention, but there is few research about the magnetic field and electromagnetic force distribution of the GIS under sweeping frequency currents. In order to solve above problems, finite element model of 110 kV three-phase common type GIS is established. And the distribution characteristics of the magnetic field and electromagnetic force of the GIS under different current frequencies are simulated. The results show that with the change of current frequency, the distribution of magnetic field in the GIS and the distribution of the electromagnetic force on the GIS shell and the conductive rod do not change. However, the magnitude of magnetic field in the GIS and the magnitude of electromagnetic force on the GIS shell change with the current frequency change. Research results provide foundation for detecting mechanical faults by using frequency sweeping characteristics of the GIS.

Abstract:Capacitive high-voltage bushing is one of the most important power equipment in substations, and their insulation status is very important for safe and stable operation of the power system. During the production and operation, insufficient drying or impregnation and ingress of external moisture may result in the humidified and unreliable insulation of bushings. Due to the particularity of the structure of the bushing, moisture is usually unevenly distributed in the capacitor core, especially in the case of external moisture intrusion. Therefore, a numerical simulation model of oil-paper-insulated double-unit laminated and 110 kV capacitor bushing is established. Frequency domain spectroscopy(FDS) characteristics under non-uniform moisture conditions are simulated. The results show that when the moisture is uneven, the tan δ-f curve shows obvious dielectric loss peaks. The frequency corresponding to the loss peaks goes up with the increase of the unevenness of moisture distribution. The FDS is sensitive to the insulation thickness and the moisture content in the final screen, and is basically not affected by the uneven axial moisture of the bushing.

Abstract:As a key component of modular multi-level converter (MMC), metallized film capacitor has the advantages of good reliability, high energy storage density and high working field strength. The failure of capacitors will affect the safe operation of the converter and even the even VSC-HVDC transmission systems. AC and DC accelerated aging test platforms are set up, and get aging samples through accelerated aging test. The aging characteristics of metallized film capacitors under different electrical stress are obtained by scanning electron microscope and confocal microscope. The results show that due to the different degradation mechanism of capacitors under different kind of voltages, the rule of capacitance value′s ruducing and the morphology of degradation point are obviously different. Through accelerated aging test, the typical morphology characteristics of the degradation point of capacitors under AC and DC voltage are obtained, which can further analyze the degradation mechanism of metallized film capacitors. The research has practical value.

Abstract:The terminology word recognition in power domain lays the foundation for a profound language understanding of power documents and the intelligent knowledge graph construction. By incorporating the morphology of the power domain vocabulary, an unsupervised approach to recognizing new terminology words in documents is proposed. Firstly, the common dictionary is used to segment the corpus. Then segmented words are combined with terminology feature-based sliding window of different sizes constituting candidate words. Furthermore, four statistics including accessor variety, information entropy, point-wise mutual information, and word frequency are computed. Finally, based on the linguistics statistics and three types of word-formation grammatical rules, those words are screened generating the last electric new words. Experimental results on a public dataset demonstrate the effectiveness of our proposed method.

Abstract:As an important bridge between the rectification module and the high-frequency inverter module in the wireless charging system of electric vehicles, the power factor correction(PFC) device not only has a serious impact on the power grid, but also causes irreversible damage to the back-end high-frequency inverter module. Therefore, fast and accurate fault detection is needed. Traditional fault detection methods have long detection time and low detection accuracy. Therefore, a fault detection method of PFC device in the wireless charging system of EVs based on hidden Markov model(HMM) is proposed. Firstly, the model is initialized. Then Baum-Welch algorithm is used for fault model training. Finally, Viterbi algorithm is used for fault detection. Simulation results show that the accuracy of PFC device fault detection using HMM is about 40% higher than that of neural network and support vector machine, which is a fast and accurate method. Therefore, HMM is used to effectively identify the type of PFC device fault in the wireless charging system of electric vehicles.

Abstract:In order to make full use of the information of the intelligent substation, help the operation and maintenance personnel to locate the faults of the secondary system of the intelligent substation more quickly and accurately, so as to ensure the safe and stable operation of the power system, a fault diagnosis method for secondary system of intelligent substation based on multi classification support vector machine(SVM) is proposed, and particle swarm optimization(PSO) algorithm is used to optimize the parameters automatically. The expert database is built according to the historical state data of the long-term operation of the intelligent substation and the processing results of the maintenance personnel. The original signal of the secondary system of the intelligent substation is a large number of {0, 1} state variables. The data group is defined in the form of switching value coding, and the data dimension of the signal is reduced by using the principal component analysis method. Finally, the fault diagnosis model of the secondary system of the intelligent substation based on the information of the terminal is constructed. The results of the comparison between the diagnosis model and the expert manual judgment show that the method proposed has excellent accuracy and applicability.

Abstract:The high-performance current loop is an important guarantee and basis for improving the performance of the permanent magnet synchronous motor servo system. In the control process, the current loop is usually susceptible to factors such as delay, sampling error so that it needs to have strong anti-disturbance capability. So an improved deadbeat current control algorithm with current correction is proposed. This method is based on the traditional deadbeat current control algorithm and improves the current sampling link. The current sampling value at time k and the current prediction value at time k are weighted to serve as a new current feedback value, and then deadbeat control is performed. In order to suppress the influence of sampling error on the current control, and then improve the anti-disturbance ability of the current in the steady state process. The simulation and experiments of a permanent magnet servo system prototype are carried out in Matlab to verify the correctness and effectiveness of the proposed method.

Abstract:As the main starting mode of pumped storage unit, the static frequency conversion starting mode has the advantages of controllable starting current, frequent starting and wide speed regulating range. When the rotor is in low speed state, the speed calculated according to the terminal voltage is not accurate. So the output electromagnetic torque error is large with the traditional control method. Firstly, the working principle of the static frequency converter system of synchronous motor is introduced. Then an improved control method of the static frequency converter(SFC) is put forward. In the low-speed phase, the open-loop control of the trigger delay angle is adopted in the rectifier circuit, so that the SFC can continuously provide sufficient acceleration torque, and the rotor can rise according to a certain acceleration. Feedforward and feedback control are adopted in the inverter circuit to make the direct current(DC) current rise rapidly and maintain at a certain level. In the high-speed phase, the double closed-loop control rectifier circuit is used to trigger the delay angle, and the inverter circuit uses the load commutation method to realize the commutation. The parameter design method of the closed-loop controller is also given, which improves the stability of the DC loop and the dynamic performance of the static inverter system. Finally, the correctness and effectiveness of the control strategy are verified by simulation.

Abstract:In order to explore the thermal effect of aluminum and pouch lithium iron phosphate(LFP) single cell on surrounding cells under overcharge condition, the thermal propagation behavior of aluminum LFP and pouch LFP under three operating conditions which include only single cell, two cell batteries close to each other, and two cell batteries separated by 1 cm are respectively studied. In the experiment, the 48 A·h pouch cell and 24 A·h aluminum cell are overcharged with a constant current of 0.5 C. Visible light monitoring, infrared monitoring and multi-channel temperature recorders are used to monitor the external appearance, external temperature and battery surface temperature changes in real time. The experimental result shows that during the overcharge, the temperature rise of the aluminum overcharged cell is 65.5 ℃and the average temperature rise rate is 0.039 2 ℃/s. The temperature rise of the pouch overcharged cell is 57.3 ℃and the average temperature rise rate is 0.014 3 ℃/s. The maximum temperature rise of adjacent aluminum cell is 44 ℃and the maximum temperature rise rate is 0.031 2 ℃/s. The maximum temperature rise of adjacent pouch cell is 7.9 ℃and the maximum temperature rise rate is 0.006 3 ℃/s. After overcharged, the expansion force generated by the pouch cell has greater impact on adjacent cellsand the mechanical stress generated by adjacent cells is greater. The experimental results can provide theoretical and experimental references for studying the influence of thermal radiation of aluminum or pouch batteries inside the module.

Abstract:Implementing "the Belt and Road Initiative" to promote the interconnection of cross border power grid is one of the key points of the development of China′s power industry during the "13th Five-Year" period. The implementation of power grid interconnection projects, especially the transnational power grid interconnection projects, will inevitably become an important direction of investment in power grid. In order to evaluate the comprehensive benefits of such investments more fully and improve the accuracy of investment decisions, the comprehensive benefit evaluation index system of such projects is constructed from three aspects:economic, social and environmental benefits. In order to make full use of the subjective and objective information, the combination method of the only reference object comparison judgement and entropy weighting method is used to determine the index weight. At the same time, matter-element extension model improved by gray correlation is used to evaluate the comprehensive benefit of such projects. The research will help improving power grid corp′s decision-making level on transnational investment and lay the foundation for effectively guaranteeing equality and mutually beneficial cooperation among countries.

Abstract:Alkaline residue is an industrial solid waste and pollutant from the process of soda production by ammonia alkali method. Developing its high-value utilizations is of significant economic and environmental benefits. Aimed at developing the application of alkaline residue as the sorbent for wet flue gas desulfurization in coal-fired power plants, the first ever industrial experiment of using the alkaline residue to substitute limestone was carried out on the flue gas desulfurization system of a 1 000 MW coal-fired electricity generation unit designed with a limestone-gypsum wet flue gas desulfurization process. Based on systematical comparison with limestone desulfurization, the performance as well as influences of the alkaline residue for desulfurization was investigated and evaluated. The experiment proves that the alkaline residue is capable to completely replace limestone in the wet flue gas desulfurization system of large-scale coal-fired power unit. Desulfurization of alkaline residue can improve efficiency of flue gas desulfurization and achieve ultra low emission, and has little influence on the quality of by-product gypsum. Alkaline residue replacing limestone as the sorbent can ensure the reliable supply of the sorbent and has the advantages of lower price and electricity consumption and higher flexibility for higher sulfur coals and can achieve good economic benefits. It also achieves using a waste to control pollution and therefore provides significant environmental benefits.

Abstract:In order to effectively analyze the scenario characteristics of wind power output, scenario analysis model based on Latin hypercube sampling(LHS) and backward reduction(BR) for the uncertain characteristics of wind speed is constructed. The model provides an important basis for rapid analysis of wind power output at any time. Firstly, wind speed characteristics are analyzed, and Weibull distribution of wind speed is introduced. Secondly, the parameter values of the Weibull distribution at each moment are calculated and a set of scenario generation methods based on LHS are proposed. Thirdly, the model of BR is used to reduce the scenarios, so that the several curves obtained can represent the change characteristics of the original scenario to greater extent. Finally, the example analysis proves that the proposed method is better than the traditional K-means clustering algorithm in compactness(CP), separation(SP) and Davies-Bouldin index(DBI), which means that the reduced scenario can better replace the original scenario.