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Optimal Configuration and Performance Analysis of Terminal Multi-energy Complementary System AI Introduction
Abstract：In order to establish a typical terminal multi-energy complementary system and know the characteristics of different optimal configurations and influence factors of its performance under different optimization objectives, this paper proposed a terminal multi-energy complementary system that integrates solar energy, wind energy and natural gas. The energy flow characteristics were analyzed based on the bus-bar structure, and an integrated optimization model for the design and operation of the system was established accordingly. Furthermore, the effects of optimization objectives and energy prices on the optimal configuration and performance of the system were studied, and the applicable scenarios of typical equipment such as micro-gas turbine, internal combustion engine and absorption chiller were illustrated, as well as the promoting effects of flexible power supply and energy storage device on the consumption of photovoltaic and wind power. The relationship between annual CO2 emission reduction ratio and fossil fuel saving ratio of the system is consistent, and that between annual cost saving ratio and CO2 emission reduction ratio is contrary under current technical and economic conditions. The most suitable natural gas price to ensure the applicable downward pressure exists and the effect of peak-valley difference of electricity price on system performance is clarified. The results can provide reference for system integration optimization design and energy price policy formulation.Keywords：multi-energy complementary;bus-bar structure;optimal configuration;performance analysis;energy price analysis23|198|0<HTML><L-PDF> <WORD> <Meta-XML>Updated：2025-06-06- Abstract：In the “dual carbon” campaign, adjustable load is an emerging adjustable resource for power grids. 13 power industry standards in the series of “Technical Specifications for Adjustable Load Grid-connected Operation and Control” was organized and carried out by the National Power Transmission Center relying on SAC/TC446 National Power Grid Operation and Control Standards Committee. Based on the standards, in this paper, the overall thinking, positioning and boundary of the 13 adjustable load standards were analyzed by reviewing the recent studies of domestic and foreign adjustable load standards. Then, the research focus and key technologies of the 13 standards were proposed. Finally, combined with typical pilots of load regulation and load participation in the market, the actual situation of application of the standards was analyzed, and the effectiveness of the standard was verified. This work can provide strong support for the improvement of adjustable load regulation capability.Keywords：adjustable load;regulation and control capacity;load assessment;index system;industry standard65|138|0<HTML><L-PDF> <WORD> <Meta-XML>Updated：2025-06-06
Harmonic Influencing Factors and Their Characterization Under Black Start Mode of Floating Power Station AI Introduction
Abstract：When floating power stations use static frequency converters to black-start floating power station units, the harmonic effects are more serious than onshore power stations due to the isolated grid system and the limited electrical structure. There is still a lack of theoretical research on the relationship between the harmonics generated during the black start process of floating power stations and their influencing factors. Firstly, the equivalence circuits on the black-start process of floating power stations were presented. Then, the mathematically analysis of harmonics was carried out on the basis of equivalence circuits, and the expression of the total harmonic distortion on its influencing factors was obtained. Furthermore,a characterization parameter of harmonic influencing factors, namely harmonic interfere coefficient, was proposed, and the physical meaning and application method of harmonic interfere coefficient were discussed. Finally, a simulation example was used to analyze the relationship between the total harmonic distortion and harmonic interfere coefficient. It is concluded that the harmonic interfere coefficient is positively correlated with the total harmonic distortion, which shows the rationality and effectiveness of the harmonic interfere coefficient.Keywords：floating power station;black start;harmonic influencing factors;characterization parameter;harmonic interfere coefficient60|220|0<HTML><L-PDF> <WORD> <Meta-XML>Updated：2025-06-06Research on Digital Transformation Architecture and Path of Power Grid Development Planning Business Under New Power System Blueprint AI Introduction
Abstract：In order to achieve the dual carbon development goals and support the development of new power system, it is necessary to gradually realize the digital transformation of decision-making business. For this purpose, the typical characteristics, development blueprint and digital transformation requirements of the new power system were analyzed, the “three stages” digital transformation system of development business was constructed, and the digital transformation idea of “from far to near, and then from near to far” was proposed. The transformation path deduction scheme based on “informatization-digitization-intellectualization” was formulated. Finally, taking the planning business as an example, the digital transformation path and implementation strategy of the planning business was deduced, the effectiveness of the method was verified. It has reference significance for the promotion of the development of the whole business digital transformation.Keywords：double carbon;power distribution system;new power system;development planning business;digital transformation111|193|0<HTML><L-PDF> <WORD> <Meta-XML>Updated：2025-06-06- Abstract：In order to solve the problem that the current domestic and foreign electrical calculation methods have too high requirements for the input parameters of the planning power grid, the predicted load of the plot was transformed into the electrical calculation load, and the realization method of spatial distribution of the future load of the plot was proposed. On the basis of studying the classical reliability formula, the concept of comprehensive failure rate was proposed. Moreover, a more practical reliability engineering calculation formula was given, which simplifies the use conditions of the classical formula. The core algorithms of electrical integration calculation (including power flow, short circuit, reliability and
Smart Grid
Summary of Differences Between Hydrogen Production From Offshore Wind Power and Direct Outward Transmission of Electric Energy AI Introduction
Abstract：In order to achieve the goals of the proposal of carbon peaking and carbon neutrality, the government is vigorously developing clean energy such as wind power. The large-capacity offshore wind power development is an important direction for the future development of wind power. However, the electrical energy transmission and grid connection of large-capacity offshore wind power has become the main bottleneck restricting the rapid development of offshore wind power. A strategy was proposed to use hydrogen energy instead of wind power for offshore energy transmission, where the electrical energy was converted into hydrogen energy on-site through electrolytic hydrogen production technology and the hydrogen transmission pipelines were constructed to transport hydrogen to land. The technical routes and application status of the traditional transmission method and hydrogen transmission method were introduced, respectively. Comparing the economic and technical differences between the power transmission method and the hydrogen transmission method, the pipeline hydrogen delivery greatly reduces the construction difficulty and construction cost compared with the offshore power transmission. Three application prospects of offshore wind power electrolysis for hydrogen production were analyzed to help achieve the carbon peaking and carbon neutrality goals as soon as possible.Keywords：offshore wind power;electrical energy transmission;pipeline hydrogen delivery;electrolytic hydrogen production51|162|0<HTML><L-PDF> <WORD> <Meta-XML>Updated：2025-06-06- Abstract：The number of turbines in the actual wind farm is large and at different operating wind speeds. It is very complicated to build a sub-synchronous oscillation study model that includes a detailed model of each turbine. Furthermore, it is time-consuming and computationally intensive to apply the model to the sub-synchronous oscillation study. Therefore, it is necessary to simplify the complexity of the sub-synchronous oscillation study by establishing a wind farm equivalent model that retains the sub-synchronous oscillation characteristics of the interaction between the wind farm and the interconnected system. In this paper, the effect of different control strategies on the sub-synchronous oscillation model in different operating wind speed intervals of wind turbines was taken into account, and the wind turbines were clustered using the K-means algorithm based on wind speed indexes. Considering the effects of different current amplitude and phase at the terminal of each wind turbine, a simplified modeling method of the collector system based on power equivalence was proposed. And the relevant wind farm simulation model was built in PSCAD/EMTDC, and the sub-synchronous oscillation modes before and after the equivalence were used to verify the rationality of this equivalence method.Keywords：wind farm;collector system;sub-synchronous oscillation;power equivalence52|113|0<HTML><L-PDF> <WORD> <Meta-XML>Updated：2025-06-06
Comprehensive Optimization of Access Point Selection for Offshore Wind Farm Integrated With Voltage Source Converter High Voltage Direct Current AI Introduction
Abstract：With the large-scale development of offshore wind power, the suitable access point to power grid for offshore wind farm is more beneficial for voltage source converter high voltage direct current (VSC-HVDC) power transmission. Aiming at large scale offshore wind farm integrated by the VSC-HVDC, the evaluation indexes of wind power accommodation capability, grid voltage stability, grid-connected point vulnerability and construction cost were proposed by analyzing the main influencing factors of grid-connected. Based on the theory of information entropy and fuzzy analytic hierarchy process, a combination weighting model was established to determine the index weights, , and a comprehensive optimization method of access point selection was proposed. Simulation results of eastern Shandong power grid of China integrated with offshore wind farm demonstrate that the proposed method enhances the capability of wind power accommodation and improves the security and stability of power grid.Keywords：offshore wind power;voltage source converter high voltage direct current (VSC-HVDC);access point selection;fuzzy analytic hierarchy process;security accommodation65|82|0<HTML><L-PDF> <WORD> <Meta-XML>Updated：2025-06-06Preparation and Its Performance of Catalyst for CO Removal From Hydrogen Rich Gas Mixture AI Introduction
Abstract：Alumina supports with different structures and properties were prepared by precipitating aluminum nitrate solution with different concentrations of ammonium carbonate solution, and then cobalt was loaded on them to obtain a catalyst for removing CO from hydrogen rich gas. The characterization and evaluation results show that the phase composition of alumina precursor can be simply and efficiently controlled and optimized, the structure, morphology, texture properties and pore size distribution of alumina can be adjusted, and thus the particle size, reduction, dispersion and surface chemical properties of loaded cobalt can be adjusted, by changing the concentration of ammonium carbonate. Finally, the catalytic performance of CO removal from hydrogen rich gas can be optimized, and the residual amount of CO is only 0.2 nmol/L, fully meeting the use requirements of Pt electrode fuel cell.Keywords：fuel cell;pore size distribution;cobalt particle size;CO removal;alumina;cobalt-based catalyst70|154|0<HTML><L-PDF> <WORD> <Meta-XML>Updated：2025-06-06
New Energy
Effect of Co-firing Ammonia on Coal Volatile Flame Characteristics and Particulate Matter Formation Behaviours AI Introduction
Abstract：Co-firing “zero-carbon, hydrogen rich, high nitrogen” ammonia (NH3) fuel in coal-fired power plant is an important technical route to mitigate CO2 emission. To explore the impacts of co-firing ammonia fuel on coal combustion and pollutant formation behaviour, the coal-ammonia co-firing experiments were carried out on a McKenna type flat-flame burner system. Combined with visible-light camera, flue gas analyser and thermophoresis probe sampling system, the influence of co-firing ammonia on the flame properties, gaseous pollutant and particulate matter formation was explored. The results show that the ammonia fuel ignites ahead of coal, and the additional heat released from ammonia combustion promotes the pyrolysis of coal and the release of volatile. Thereafter, it promotes the ignition and combustion of volatile, resulting in the increase of flame height and temperature. The added NH3 is partially converted into NO in the volatile flame, resulting in a notable increase in NO concentration. Adding NH3 improves the equivalent ratio of gaseous fuel, which promotes the conversion of volatile to soot, and finally increases the yield of soot particles.Keywords：coal-fired power plant;carbon emission;ammonia fuel;volatile flame;particulate matter;soot89|202|0<HTML><L-PDF> <WORD> <Meta-XML>Updated：2025-06-06Retrofitting Strategy and Operating Technology of Pure Burning Zhundong Coal in a 135 MW Circulating Fluidized Bed Boiler AI Introduction
Abstract：Zhundong coal is rich of alkali metals, and coal ash contains large amounts of Na and K element, which can easily lead to slagging and contamination problems, and affect the normal operation of the boiler. This paper focused on the slagging characteristics of the 2×135 MW circulating fluidized bed (CFB) boilers in the actual operation burning Zhundong coal, and proposed the corresponding renovation plan and operation technology through mechanistic analysis. The results show that increasing the gas velocity at the separator inlet can improve the separation efficiency and circulating rate; increasing the area of platen heating surface and improving the efficiency of separator help to achieve the cooling of the furnace chamber; diluting alkali metal content with pulverized coal boiler ash can reduce the formation of alkali metal sulfate. After the optimization, the target boiler was put back into operation at the original load for about 8 months. The comparison with the operation effect before modification shows that the staining and slagging problems are significantly improved while burning pure Jundong coal at high efficiency and low cost, which verifies the feasibility of the proposed technical solution and also provides a reference for other Jundong coal utilization engineering projects.Keywords：circulating fluidized bed (CFB) boiler;Zhundong coal;contamination;slagging;cyclone efficiency improvement94|121|0<HTML><L-PDF> <WORD> <Meta-XML>Updated：2025-06-06Analysis on Combustion Instability Characteristics of Model Swirl Combustor With Gas Fuel AI Introduction
Abstract：Combustion instability is easy to occur under lean combustion of gas turbine. Analyzing and predicting the characteristics of unstable combustion is of great significance to ensure the normal operation of combustion chamber. The flame describing function (FDF) of combustion chamber was obtained by numerical simulation, and the thermoacoustic instability characteristics of combustion chamber were predicted by combining the low-order thermoacoustic network model. Firstly, the operating conditions and main frequency of oscillating combustion were obtained through the self-excited oscillation experiment of model swirler combustor.Secondly, by using large eddy simulation (LES), the response characteristics of heat release rate of flame combustion under different inlet disturbances were obtained, and the FDF was fitted. Finally, the low-order thermoacoustic network model of the combustion chamber was established, and the instability characteristics of the combustion chamber were analyzed. The results show that the oscillation characteristics predicted by the model are consistent with the experimental data, indicating that the model can predict the combustion instability characteristics from the mechanism.Keywords：gas turbine combustor;combustion instability;thermoacoustic network model;large eddy simulation (LES);flame describing function (FDF)51|74|0<HTML><L-PDF> <WORD> <Meta-XML>Updated：2025-06-06Study on Variable Working Condition Characteristics of 600 MW Direct Air Cooling Condenser AI Introduction
Abstract：The coal consumption of direct air cooling unit is higher than that of wet cooling unit, and its back pressure is easily affected by environmental factors. Therefore, it is of great significance to study the exhaust pressure characteristics of air condensing unit under variable working conditions for the safe and economic operation of the unit.The ε-NTU method was used to establish the mathematical model of the 600 MW direct air cooling unit under the condensing condition. The characteristic curves of the condenser under the condensing condition were calculated. The effects of the face wind speed, ambient temperature and exhaust flow rate on the exhaust pressure were analyzed. The conclusions are as follows: When the ambient temperature is higher and the exhaust steam flow is constant, the back pressure economy is better when the head wind speed is 2.5 m/s. During the period of high temperature in summer, the exhaust steam pressure of condenser increases significantly with the increase of exhaust steam flow and the decrease of head-on wind speed. It is necessary for the unit to operate under limited load and appropriately increase the fan speed to reduce the back pressure. When the ambient temperature is low, the exhaust steam flow rate and the face wind speed have little influence on the exhaust steam pressure of the condenser, so it is necessary to take anti-freezing measures. Appropriately increasing the exhaust steam pressure of the condenser is beneficial to the safe operation of the air-cooled island.Keywords：direct air cooling;condenser;variable working condaton;characteristic curve;run advice57|154|0<HTML><L-PDF> <WORD> <Meta-XML>Updated：2025-06-06- Abstract：With the development of society, severe energy situation, as well as higher and higher environmental protection requirements, how to improve energy efficiency and achieve sustainable development of society has become the research goal of more and more scholars. The cascade utilization based on energy grade and multi-energy complementary distributed energy system are the important development direction of energy technology in the future. One of them is the combined cooling and electricity cycle, which combines the organic Rankine cycle with the ejector refrigeration cycle. The ejector is the key component in the combined cycle of cooling and electricity. The ejector was modeled by the most commonly used one-dimensional isobaric mixing model. The thermal efficiency and exergy efficiency of the cycle were analyzed. The effects of condensation temperature, evaporation temperature, outlet temperature of steam generator and exhaust pressure on the cycle performance were analyzed. The analysis of the system shows that the greatest loss occurs in steam generator, condenser and ejector.Keywords：combined cooling and power cycle;ejector;thermodynamic analysis;thermal efficiency;exergy efficiency32|46|0<HTML><L-PDF> <WORD> <Meta-XML>Updated：2025-06-06
Fault Diagnosis of Power Plant Induced Draft Fan Based on PNN-WNN-DS Information Fusion AI Introduction
Abstract：Aiming at the problems of complex operating conditions of induced draft fan, harsh working environment, and easy failure of power plant induced draft fan, a fault diagnosis method of the improved dempster-shafer evidence theory was proposed. In this method, the probabilistic neural network (PNN) and wavelet neural network (WNN) were used for preliminary diagnosis, and the evidence bodies were formed according to the output of PNN and WNN. Then the improved D-S fusion method was used for fusion diagnosis. The improved D-S method distributes conflict information according to the trust degree of the evidence and the focal element, so that the support rate of the focal element with high trust degree is strengthened, and the focal element with low trust degree is weakened, which makes the fusion diagnosis result more reasonable. The simulation results show that the proposed method can effectively diagnose the vibration fault of induced draft fan, avoid misdiagnosis, improve the accuracy of diagnosis, and reasonably distribute conflicting information.Keywords：power plant induced draft fan;focal element;fault diagnosis;improved D-S evidential theory51|54|0<HTML><L-PDF> <WORD> <Meta-XML>Updated：2025-06-06Research on Aerodynamic and Strength Performance of Last Stage in High-Pressure Cylinder of Steam Turbine Under Variable Working Conditions AI Introduction
Abstract：Using the one-way fluid-structure interaction method, the aerodynamic and strength performance of the last stages in high-pressure cylinder of a steam turbine were numerically investigated at four extraction percentages (0%, 8%, 15% and 20% of the total mass flow rate in stages). The aerodynamic efficiency of last stages, as well as the aerodynamic loads on the blades, was obtained under design and off-design conditions. With the computed aerodynamic loads, the strength performance of the last rotor blade was analyzed, and the maximum stress and deformation in rotor blade at various conditions were derived. The results show that the power output of last two stages is nearly linearly decreased with the increase of extraction percentage. If the extraction percentage equals to 20%, the power output is reduced by 44% as compared with the design case. As the extraction percentage increases, the total temperature at last stage outlet is gradually increased. With 20% extraction rate, the total temperature at last stage outlet is increased by about 10 ℃ compared with the design case. The extraction rate has a significant influence on the leakage performance in the tip and hub labyrinth seals of last stage, resulting in the variations of total-total isentropic efficiency, reaction degree and outlet flow angle distributions along the spanwise direction in the off-design conditions. The influence region in the last stage is mainly existed within 30% blade span near hubs due to varied extractions. Compared with the original design case, the total-total isentropic efficiency, reaction degree and outlet flow angle in the last stage are varied by 3.8%, 1.6% and 2.4° at most as the extraction percentage varies from 0 to 20%. With the centrifugal and aerodynamic forces, the maximum stress in the last stage rotor blade is occurred at the upstream side bottom fillet of T-shape root, and the maximum displacement in blade tip is 0.443 mm. As the extraction percentage increases, the maximum stress and maximum displacement in last stage rotor blade are almost linearly decreased.Keywords：steam turbine;aerodynamic performance;blade strength;high-pressure cylinder44|104|0<HTML><L-PDF> <WORD> <Meta-XML>Updated：2025-06-06- Abstract：In order to meet the requirements of peak regulation, the power load of the steam turbine unit changes greatly. The heating parameters of the steam extraction from the reheated steam pipe also fluctuate greatly. The intermediate pressure (IP) cylinder regulating valves of the steam turbine participate in the regulation to stabilize the heating parameters. For a 300 MW steam turbine adopting such heating mode, the regulation characteristics of the IP cylinder regulating valves was studied experimentally under power load of 250 MW and extraction steam flow of 52.20-53.94 t/h. The results show that, as the opening of regulating valves decreases, the inlet steam flow of the IP cylinder decreases gradually, and reheated steam pressure increases gradually. When the minimum opening of the IP cylinder regulating valves is 24.97%, the inlet steam pressure of the IP cylinder is 3.44 MPa, and pressure of the main extraction steam pipe is 3.13 MPa. The maximum pressure ratio of the high pressure (HP) cylinder is 3.13 and the minimum value is 2.65, decreasing gradually. The exhausting steam temperature of the HP cylinder increases gradually, the highest is 331.76 ℃, the lowest is 312.97 ℃. The efficiency of the IP cylinder is gradually reduced, from 93.37% to 84.78%. The steam enthalpy drops of the HP cylinder and the IP cylinder do not change a lot. However, the first stage extraction steam pressure and the HP cylinder exhausting steam pressure increase. The flow rate of the HP and IP cylinders is reduced, and the work capacity of the HP and IP cylinders is reduced, resulting in the decrease of power load of 9.79 MW. The safety operation index of the unit shaft system remains stable.Keywords：combined heat and power units;heating retrofit;steam turbine;intermediate pressure cylinder regulating valve;regulation characteristics58|84|0<HTML><L-PDF> <WORD> <Meta-XML>Updated：2025-06-06
Power Generation and Environmental Protection
