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- Abstract：Aiming to the precision and real-time analysis requirement of transient component in power system fault signal, a new time-frequency correlation analysis algorithm was presented, whose frequency domain segmentation is different from Mallat. This algorithm can run in real time, which makes precision, flexible and focused domain segmentation. At the same time, time-frequency correlation in the full frequency-range is maintained. An FPGA-based example module to implement this algorithm was designed. A MATLAB-based distributed parameter grid simple model was established. Simulation on this module provided 500 kHz-sampled-value sequence of fault signal. The capability and practicability was preliminarily proved by providing the sampled-value sequence to the example module. The application strategy for designing relay protection algorithm was suggested, and prospects of the work associated with this algorithm was provided.Keywords：relaying protection;transient based protection;wavelet transformation;time-frequency correlation analysis;field-programmable gate array (FPGA)25|8|0<HTML><DownloadPDF> <Meta-XML>Updated：2025-06-06
- Abstract：Under the development trend advocated by the new energy policy, the development of new energy vehicles in China has made great progress, and the battery energy density of electric vehicles has increased. The power of the DC charging pile charged by the corresponding electric vehicle power battery is getting higher and higher, so that the charging power of the DC charging pile accounts for an increasing proportion of the total load power of the distribution layer, which brings new challenges to the planning and construction of the distribution network. According to the arbitrarily interruptible charging process of the electric vehicle, it is proposed that when the total scale of the electric vehicle reaches a certain amount, the overall charging power of the electric vehicle can be flexibly controlled, thereby achieving the purpose of peak shaving for the power grid. Through the analysis of the power and control mode of the electric vehicle charging pile, it is concluded that when the number of DC charging piles and their total power in the distribution network load reaches a certain scale, in the cluster control mode, it is more suitable to participate in the peaking of the distribution network layer.Keywords：electric vehicle;distribution network;DC charging pile;cluster control;peak shift18|5|0<HTML><DownloadPDF> <Meta-XML>Updated：2025-06-06
- Abstract：Under the background of energy internet, the scale of renewable energy interconnection is increasing day by day. Due to the strong randomness of renewable energy generation power, the so-called "bilateral stochastic problems" appears in the operation of the power system, which affects the safety and stability. How to manage all kinds of renewable energy economically and effectively is one of the key technologies to realize the energy internet. In order to realize the overall optimization of microgrid operation, a multi-objective optimization model was established for microgrid including various distributed generators (DG) with the lowest comprehensive power generation cost and the best environmental benefits as the optimization objectives. The genetic algorithm is used to optimize the energy management. The simulation results of a microgrid with multiple DGs running on the grid show the effectiveness of the optimization model and algorithm.Keywords：energy internet;micro-grid;distributed generator;energy management26|4|0<HTML><DownloadPDF> <Meta-XML>Updated：2025-06-06
- Abstract：When distributed generator (DG) is connected to the microgrid, the microgrid will change from single source system to multiple source system, which will change the power flow distribution and fault short-circuit current flow of the original network, the sensitivity will decrease, and the phenomenon of false rejection will occur. In this paper, the influence of DG on the protection of microgird is analyzed, and the model is built on the PSCAD. The effect of DG on the protection of microgird is verified.Keywords：distributed generator;microgird;current protection22|4|0<HTML><DownloadPDF> <Meta-XML>Updated：2025-06-06
- Abstract：Voltage source converter based high voltage direct current (VSC-HVDC) transmission systems has the advantages of good active and reactive power control capability and more suitable for multi-terminal transmission system. It is considered as a potential transmission mode. Research on control and stability of VSC-HVDC is an important factor affecting the safety and performance of transmission system. Aiming at the study of control strategies of VSC-HVDC systems, the topologies and decoupling and additional control methods of VSC-HVDC were analyzed. Then it extends from the basic two-terminal topologies to the multi-terminal and hybrid topologies, focus on the droop control, fault ride through capability of VSC-MTDC and control of hybrid direct current transmission system. Next, this paper discussed the stability and control schemes of VSC-HVDC for wind power integration, which will provide reference for future research.Keywords：voltage source converter based high voltage direct current (VSC-HVDC);topology;decoupling control;droop control;fault ride through;wind power integration57|10|0<HTML><DownloadPDF> <Meta-XML>Updated：2025-06-06
- Abstract：The increasing peak-valley load difference, the increasing scale of external power and the priority of new energy consumption in Shanghai required the flexibility of peak load regulation. In this paper, the characteristics of Shanghai power load were analyzed systematically, and the optimization strategy and implementation scheme of Shanghai power supply structure were analyzed in detail from the perspective of enhancing the flexibility of peak load regulation. The results show that the installation of power supply in Shanghai in the future should focus on increasing gas turbine generating unit and improving peak load regulation performance. The strategy of replacing coal-fired generating units with gas turbine for Shanghai's gap capacity consists of the construction of gas turbine at the original site of retired coal machine and the planning construction of gas turbine power points in the city's outskirts. Shidongkou power plant had the construction condition of gas turbine at the original site of existing small coal-fired power plants. Jinshan, Qingpu, Jiading, and Pudong are suitable for the new gas turbine construction.Keywords：power load characteristics;power structure;optimization strategy;gas turbine28|4|0<HTML><DownloadPDF> <Meta-XML>Updated：2025-06-06
Energy Internet
- Abstract：Salt-containing emission of flue gas after coal-fired wet flue gas desulfurization is one of the reasons for large-scale haze in China. The problems in wet desulfurization of coal-fired flue gas were analyzed. The present situation of 'bleaching' and coloured plume management technology was introduced, it is necessary to objectively evaluate the 'bleaching' effect of flue gas from the aspects of investment cost, operation cost and emission index. Dry and efficient desulfurization technology should be researched and developed to reduce the emission of water vapor, flue gas and salt economically and practically, and reduce the haze.Keywords：wet desulphurization;haze;coloured plume20|4|0<HTML><DownloadPDF> <Meta-XML>Updated：2025-06-06
- Abstract：Scaling is one of the main problems affecting the safe and stable operation of limestone gypsum wet flue gas desulfurization (WFGD) system. In a power plant, the scaling of the primary tower and the mist eliminator of 330MW unit was serious, which had affected the normal operation of the flue gas desulfurization system. For this problem, the paper systematically analyzed the absorber and the operation parameters of the desulfurization system. It was found that the fault of the pulse suspension system, the blockage of the mist eliminator nozzle and the fluctuation of the slurry parameters were the main causes of the scaling in the absorber. By strengthening the flushing of the mist eliminator, monitoring and comparing the parameters of the mist eliminator and the slurry pulse pump at the beginning and normal operation, reasonably controlling the slurry density, pH value, oxidation air volume and fluoride ion concentration, the scaling of the primary tower had been effectively alleviated.Keywords：desulfurization;absorber;scaling;preventive measure29|5|0<HTML><DownloadPDF> <Meta-XML>Updated：2025-06-06
- Abstract：A combined numerical simulation is conducted to couple fluid flow between exhaust hood and last-stage blades of a 600 MW steam turbine using the computational fluid dynamics software CFX. Based on quadratic orthogonal regression design, the flow guide device at the top of the exhaust hood is installed. The regression orthogonal equation between the installation parameters of the guide plate and the coefficient of static pressure recovery is obtained. The equation is remarkably unlost with nonlinear relation and there is no influence among the three factors. The optimal solution of the regression equation is solved. The channel vortex is broken and the aerodynamic performance of the exhaust hood is improved obviously after the diversion plate is installed. The static pressure recovery coefficient of exhaust hood outlet is increased by 3.008%, the total pressure loss coefficient is reduced by 5.789% and the standard deviation of the outlet is reduced by 3.043. The static pressure recovery coefficient of exhaust hood outlet under different loads after the optimization is always higher than that before the optimization.Keywords：steam turbine;exhaust hood;flow guide device;quadratic regressive orthogonal experiment;aerodynamic performance31|4|0<HTML><DownloadPDF> <Meta-XML>Updated：2025-06-06
- Abstract：In order to improve boiler efficiency and reduce the emission of boiler pollutants, this paper take a power plant as the research object, the overall optimization of the boiler's air preheater seal device horizontal flue ash blower system and high-pressure economizer.were carried out, chemical cleaning and heat treatment were also carried out for bolier, and the thermal efficiency and pollutant discharge of the boiler ware tested before and after the optimization. Compared with that before the optimization, the efficiency of boiler is increased by 2.3% under different loads and the coal consumption is reduced at the same time. The unburned carbon heat loss and the air leakage rate of air preheater is also greatly reduced. The concentration of NOx discharged from the boiler has reached the requirement. The optimized reform has achieved the expected effect.Keywords：boiler efficiency;fume exhaust temperature;air-preheater;heat loss;optimization and transformation36|4|0<HTML><DownloadPDF> <Meta-XML>Updated：2025-06-06
- Abstract：A low carbon comprehensive evaluation index system was established for coal fired power generation enterprises according to the evaluation principle. The three-tier index system structure model was built based on analytic hierarchy process(AHP), and the importance degree of different indicators could be determined at different levels according to the experience of experts. The weight of each index was determined by using AHP software, each index score was calculated and standardized after determining the benchmark value method. Finally, the comprehensive evaluation of low carbon development of coal-fired power generation enterprises was realized by using weighted scoring method to synthesize the quantitative results of indicators. The low carbon comprehensive level were compared and the results were analyzed taking two power plants in the region as an example. Combined with the analysis results, the corresponding suggestions for low carbon development of coal-fired power generation enterprises in China were given.Keywords：coal-fired power plant;analytic hierarchy process;low carbon evaluation32|5|0<HTML><DownloadPDF> <Meta-XML>Updated：2025-06-06
- Abstract：This paper took a 300 MW condensing power plant heating reform as an example. According to the parameters of heat user, two different renovation plans between reheat cold section and reheating section were analyzed. The results show that steam form reheating section through temperature reduction and pressure reduction is more fitting for the heating load and can meet the different heating demand. Furthermore, the economic performance was also analyzed. The unit can reduce the coal consumption of power generation by 7.22 g/(kW·h) under average extraction conditions, equivalent to 11 921 t every year. Considering the income of coal saving, the project investment payback period is 2.94 years, which has good economic benefits.Keywords：industrial heating;reheat cold section;reheating section;pressure and temperature reducing37|6|0<HTML><DownloadPDF> <Meta-XML>Updated：2025-06-06
- Abstract：According to the standard, after the anti-corrosion coating is immersed for a certain period of time, if there is no foaming, cracking, falling off, etc., the evaluation result is qualified. However, the adhesion and the corrosion resistance of some of the qualified coatings are greatly reduced. In this paper, eight kinds of anti-corrosion coatings qualified after soaking were selected, and the dry adhesion and wet adhesion after soaking in acidic environment were tested. The test results showed that the adhesion of some coatings after immersion was greatly reduced or lost, the metal matrix has obvious corrosion characteristics; the adhesion of some coatings was reduced; the adhesion of the two kinds of anti-corrosion coatings cured at room temperature was slightly increased. It can be seen that by comparing the dry/wet adhesion of the coating or tracking the change of adhesion during the coating service, the maintenance performance and development trend of the coating performance can be quantitatively grasped.Keywords：anti-corrosion coatings;wet adhesion;rapid test6|4|0<HTML><DownloadPDF> <Meta-XML>Updated：2025-06-06
Power Generation and Environmental Protection
- Abstract：Randomness, intermittence and fluctuation are features of new energy, which includes wind energy and solar energy, and power forecasting is an effective solution. The characteristics of wind power output and forecasting model are fully considered to propose piecewise support vector machine (PSVM) and neural network (NN) model; the effort of weather condition on photovoltaic is analyzed to optimize the forecasting model. The case studies from several wind farms and photovoltaic power stations prove that the proposed models have higher precision, which offer support for reliability analysis of power output forecasting.Keywords：wind power;photovoltaic;power forecasting;support vector machine;neural network;wavelet analysis41|7|0<HTML><DownloadPDF> <Meta-XML>Updated：2025-06-06
- Abstract：Volumetric solar receiver is one of three main categories of solar receivers. It has great application prospect due to the simple structure, high thermal efficiency, and the air exit temperature can reach above more than 800℃. The porous material is used instead of tube as absorber in volumetric solar receiver to heat the working medium, and the incident radiation can be absorbed gradually from outside to inside. In this study, an one-dimensional volumetric solar receiver calculating model based on porous foam ceramics is constructed. The temperature distributions and radiation absorption efficiencies at different conditions are analyzed. The results show that both the outlet air temperature and the depth for the temperature of air and ceramic solid reaching to stability decreases apparently with decrease of porosity of ceramic foam, but the temperature of front surface of the receiver increases gradually. With decrease of porous ceramic diameter, the air exit temperature decreases gradually, and the depth for the temperature of air and ceramic solid reaching to stability is decreasing, while, the diameter change has little effect on the temperature of front surface. The air exit temperature increases apparently with decrease of air flow rate and rise of inlet air temperature, and increases with increase of incident radiation intensity. The energy absorbing efficiency is decreasing with decrease of air flow rate and rise of inlet air temperature, and decreases with increase of incident radiation intensity.Keywords：foam ceramics;solar receiver;volumetric absorbing;numerical simulation35|4|0<HTML><DownloadPDF> <Meta-XML>Updated：2025-06-06
Research on the Method of Stabilizing the Power Output Fluctuation of Wind Farm by Electric Vehicles
Abstract：Owing to the inherent randomness and intermittency of wind power, the output power of wind farm tends to fluctuate greatly. However, considering the high cost of energy storage device, it is not good for the wind farm to configure energy storage device. This paper studies the fluctuation of output power fluctuation in the wind power field considering the participation of electric vehicles. Firstly, according to the requirement of the national standard of stroke, "active power change", the rate of output power of wind farm is described by the concept of climbing rate. Then, using the robust optimization method to deal with the uncertainty of wind power, wind turbines and electric cars, coordinated control of bi-level optimization model:the upper model decision makers is a wind farm, with wind farms sell electricity utility maximization as the objective function; The lower-level model decision makers are electric car owners, and the cost of electric power costs is minimized to the target function. In addition, this robust optimization model is transformed into a hybrid integer linear programming problem by using the linear programming dual theorem and Karush-Kuhn Tucker (KKT) optimality conditions. Finally, the effectiveness of the proposed model and method is verified by simulation.Keywords：wind farm;electric vehicle;power fluctuation;robust optimization;double layer optimization29|5|0<HTML><DownloadPDF> <Meta-XML>Updated：2025-06-06
New and Renewable Energy
