Characteristics Of Power Plant Research Articles

Modeling of thermal power plants in the study of reliability of power supply and energy security

RELEVANCE. Maintaining the required level of energy security (ES) and reliability of fuel and energy supply is one of the priority tasks in the management of the energy sector. In the functioning of the fuel and energy complex various threats are possible, which can lead to the violation of the reliability of fuel and energy supply and the emergence of shortages ofvarious types of energy resources. To assess the level of energy security, approaches are considered to form a mathematical model of the FEC, which combines all sectors of the energy sector. Despite the trends of transition to low-carbon energy sources associated with energy transformation, thermal power plants remain one of the main sources of heat and electricity.Due to the ability to generate large amounts of heat only thermal power plants can be a source of centralized energy supply of large territories. In this regard, when modeling the fuel and energy complex, it is necessary to develop mathematical models of TPPs, which will correctly reflect the technological processes that affect the reliability of energy supply. OBJECT. Development of mathematical models of interaction of electric power, heat supply and fuel systems within the framework of thermal power plants designed to study energy security and reliability of fuel and energy supply. METHODS. Mathematical modeling of fuel consumption dependences on electrical and thermal load at thermal power plants is used as methods. To obtain analytical dependencies, the least squares approximation of the consumption characteristics of thermal power plants was carried out. RESULTS. As part of the work, analytical dependences of fuel consumption on thermal and electrical load for various types of thermal units were obtained. For all considered steam turbines, linear dependences of theamount of heat supplied to the turbine on its load (electrical and / or heating depending on the type of turbine) were obtained. For boilers, an approximation of the dependence of efficiency on thermal load was carried out. According to the results of the approximation, a linear dependence is assumed. For gas turbine installations, an approximation of the dependence of the efficiency on the load was carried out, according to the results of which a second-order polynomial was obtained. CONCLUSION. The paper investigates the problem of mathematical modeling of the interconnected operation of fuel, heat and power and electric power systems within the framework of the functioning of the energy sector. Analytical dependences are obtained for different types of generating equipment, including boilers, steam turbines and gas turbine installations. The obtained dependences are necessary for the analysis of energy security and reliability offuel and energy supply. The models of thermal power plants presented in the paper are the most suitable for the analysis of energy security and reliability of fuel and power supply, as they provide the necessary accuracy of calculations and take into account the specifics of various generating equipment, without dropping to the level of microparameters.

Can China achieve carbon neutrality without power shortage? A substitutability perspective

The thermal power sector is responsible for more than 40% of China's carbon mitigation targets, making it critical in achieving carbon neutrality. However, the adoption of the “one-size-fits-all” discontinuation and “campaign-style” mitigation, driven by mandatory national regulatory constraints, has triggered pressing livelihoods and economic shocks such as electricity restrictions and shortages. To balance the carbon mitigation targets with electricity security in China, this study utilizes Morishima elasticity of substitution to identify heterogeneous production strategies for each plant under carbon neutrality. More specifically, how thermal power plants respond to carbon reduction targets. Results indicate that almost half of the thermal power plants could reconcile national targets with corporate profits, while the remaining plants could only meet national binding targets by reducing production. Additionally, about 20% of inefficient plants will opt to transfer emissions, such as increasing weakly regulated emissions, to secure revenue. The basic characteristics of thermal power plants under different production strategies are also analyzed. Finally, this study discusses how to develop electricity-carbon synergies and prevent productive speculation under the carbon neutrality transition from the perspectives of corporate production and tax deferment policy, and propose corresponding policy suggestions.

Slagging-fouling evaluation of empty fruit bunch and palm oil frond mixture with bituminous ash coal as co-firing fuel

The empty fruit bunch (EFB) and palm oil frond mixture, called EFFR, can be utilized as co-firing fuel for coal-fired power plants to reduce carbon emissions. However, the addition of EFFR can influence the ash deposition characteristic of power plant fuel due to its high chlorine and alkali content. This study evaluates the slagging-fouling propensity of EFFR when blended with bituminous ash coal in several compositions. Theoretical methods using indices and the SCK ternary phase diagram, experimental procedure with drop tube furnace combustion, and ash observation methods utilizing visual and instrumental observations are carried out. The results show that co-firing EFFR can effectively reduce ash deposition. The slagging-fouling risk tendency slightly increases, adding up to 15 wt% EFFR has a higher slagging tendency, while the addition of 20 wt% EFFR has a higher fouling tendency. According to a thorough evaluation, co-firing 5–20 wt% EFFR with bituminous coal is still acceptable.

Short-circuit Current Engineering Calculation Method Considering Crowbar Operation Priority Degree of DFIG

When fault occurs in high wind power proportion grid, the control strategy and external characteristics of the wind power plant are affected by voltage drop of grid, so the traditional short-circuit current engineering calculation is difficult to converge. A short-circuit current engineering calculation method for high wind power proportion grid, considering grid node importance evaluation and crowbar protection of DFIG(double-fed induction generator), is proposed. This paper proposes the external equivalent model of the DFIG when fault occurs in grid, considers voltage drop degree and node importance indexes, and determines the weight of each index through Delphi method. The DFIG crowbar operation priority is evaluated to ensure the successful convergence of calculation and the maximum voltage support of wind power plants. The study case shows that proposed method is superior to the traditional method.

Analysis of primary frequency regulation characteristics of PV power plant considering communication delay

With the large-scale development of photovoltaic power generation, photovoltaic power plants (PVPP) are required to participate in primary frequency regulation to maintain the stability of the power system. Existing researches seldom consider the influence of the data communication delay of PVPP on the primary frequency regulation ability of PVPP. From the perspective of the communication system structure and control strategy of PVPP, this paper firstly analyzes the composition of the communication delay involved in the process of primary frequency regulation. Through the simulation of the three-machine nine-bus power system, the frequency regulation performance of PVPP under different time delays are analyzed. Furthermore, the influence mechanism of time delays on the primary frequency regulation results is discussed. Finally, two optimization schemes are proposed, which can reduce the communication delay and improve the tolerance of PVPP to the communication delay, respectively. The research results show that there are mainly two types of delays in the primary frequency regulation process of traditional large-scale PVPP. The longer the delays, the weaker the PVPP’s ability to participate in primary frequency regulation. In addition, the optimization of PVPP communication system and control strategy of inverters can help improve the frequency regulation ability of the PVPP, thereby maintaining the frequency stability of the power system.

Study on refined mathematical model of solar chimney power plant integrated with seawater desalination and the influence of dewing

In order to more accurately evaluate the operation and output characteristics of the solar chimney power plant integrated seawater desalination, a refined mathematical model for unsteady heat and mass transfer was built under consideration of the convection heat transfer mechanism of the collector, dewing phenomenon, and the disturbance to the hot airflow caused by the oblique-toothed flow channel boundary. The influence of nighttime dewing and humid environments on system performance was discussed. The results show that it is feasible and more appropriate to use the forced convection heat transfer coefficient of bellows to consider the influence of the oblique-toothed flow channel boundary; the refined mathematical model is also more accurate and reliable. Due to the effect of seawater heat storage, dewing has little effect on system performance, and the integrated system has a better anti-dewing negative impact characteristic. However, when the ambient humidity reached a higher level, dewing had a greater negative impact on freshwater production. The critical value of relative humidity for dewing to occur is 51 %. When the relative humidity increases from 45 % to 60 %, the daily utilization efficiency of solar energy decreases from 27.4 % to 22.5 %.

Modeling and control method of combined heat and power plant with integrated hot water storage tank

To enhance the flexibility of conventional power plants, a dynamic mathematical model of a combined heat and power unit is developed and verified in this study using field data, and the maximum relative error is less than 5%. Subsequently, the dynamic characteristics of the coal-fired power plant with the hot water storage tank are studied, and the temperature distribution curve inside the hot water storage tank is obtained. Finally, a new coordinated control system with an integrated hot water storage tank is designed. The new coordinated control system reduces the fluctuation in the heating load caused by the unit in the process of changing the load. The integral of absolute value of the error criterion and integral of time multiplied by the squared error criterion results for unit loads at different variable load rates are at least 200 and 50,000 lower compared to conventional control methods. This study provides a new solution to the problem that the current conventional turbine and boiler coordinated control system cannot address the difficulty of renewable energy power consumption, which is important for the safe and stable power grid operation after the large-scale grid connection of renewable energy power.

Discrete impedance method for the oscillation analysis of pumped-storage power plants

As the proportion of new energy increases in modern power systems, pumped-storage power plant attaches significance to balancing power supply and demand. Its operational stability has attracted extensive attention. Since the hydraulic characteristics of the pumped-storage power plant with a complicated conduit system are rather complex, it is difficult for the traditional continuous impedance method to obtain analytical solutions to the frequency responses directly. Therefore, an equivalent circuit modeling-based discrete impedance method is proposed to address this problem. The discrete impedance method possesses accurate modeling precision and is applied to the oscillation analysis of a pumped-storage power plant with a complex hydraulic network. Furthermore, the influences of the pump-turbine impedance and the pipe friction loss on the oscillation characteristics have been discussed. Numerical results indicate that the variations of the pump-turbine impedance and pipe friction loss impact the decay coefficients of different oscillation orders, thus influencing the system’s stability. However, they can hardly affect the eigen frequencies of the system. The proposed discrete impedance provides an alternative to the complex frequency analysis of complicated hydraulic systems.

Emergency evacuation time model of nuclear power plant pedestrians

The construction of nuclear power plant is usually multi-phase. In the coexisting period of operation and construction, the types of pedestrian in nuclear power plant are complicated. Like Fukushima accident, nuclear power plant accident is dangerous and easy to cause mass panic. In order to improve the efficiency of emergency evacuation in nuclear power plant and accurately obtain the evacuation time of nuclear power plant pedestrians, a pedestrian evacuation time model is established. Firstly, by studying the general layout characteristics of nuclear power plant, nuclear power plant is divided into three areas, protected area, management area and construction area. Secondly, the pedestrian flow movement monitoring data of nuclear power plant are analyzed to obtain the pedestrian movement characteristics and speed-density curves of different locations(facilities) in different areas of the plant, which will provide data support for establishing the pedestrian evacuation time model of nuclear power plant. Thirdly, the evacuation time of nuclear power plant is divided into three parts: pedestrian reaction time, pedestrian walking time and pedestrian waiting time. The evacuation time model of nuclear power plant pedestrian is obtained by analyzing and modeling these three parts respectively. Finally, taking a nuclear power plant as an example, three types of evacuation areas are set up according to the layout characteristics and construction status of nuclear power plant. The model was used to calculate the evacuation time of different types of areas. Based on multi-agent pedestrian flow simulation method, emergency pedestrian flow simulation of three types of evacuation areas is obtained. The results of the model are compared with the simulation results, and it is found that the model has good matching in different nuclear power plant areas, which verifies the rationality and accuracy of the model.

Research on Technical supervision of Steam turbine in nuclear power plant

Based on the technical characteristics of nuclear power turbine, the technical differences between nuclear power turbine and thermal power turbine are analyzed. Based on the premise of nuclear safety and combined with the characteristics of nuclear power plants, the feasible supervision mechanism of conventional island turbine and the daily management responsibilities of nuclear power supervision are studied. Extensive research and collection of nuclear power related data, including technical specifications, operation procedures, maintenance procedures, etc., through the analysis and collation of these data, the technical supervision content of nuclear power conventional island turbine is studied, highlighting the differences with thermal power turbine technical supervision.

Basic Characteristic Analysis of Self-provided Power Plant in Iron and Steel Industry

Self-provided power plants are set up in order to maintain normal operation in some high energyconsuming industries in the era of power shortage in China. In a specific historical period, it effectively alleviated the problems of insufficient power supply and low reliability of the power grid, and promoted the rapid development of the national economy. The construction of self-provided power plants in the steel industry is to save electricity costs and improve the operational reliability of important units. This paper analyzes the basic production electrical characteristics and equipment load characteristics of the self-provided power plant in iron and steel industry, and summarizes the adjustment ability of the equipment from two aspects of power generation side and load side.

METHODS OF MATHEMATICAL MODELING OF THE POWER CHARACTERISTICS OF A WIND TURBINE

At the moment, the Russian wind energy market uses wind power plants, which have their own range of parameters and characteristics. There are also various methods by which it is possible to calculate electricity generation by nominal capacity and wind potential data for the site where the construction of a wind farm is planned. But for this, it is necessary to have a power characteristic for a particular wind power plant. The nominal wind speed is often used for its construction. (Research purpose) Applied analytical and computational methods, in particular the Binov method, the method of approximation of the function - linear interpolation, this is a way to calculate the intermediate value of the function from its already known several values. (Materials and methods) Applied analytical and computational methods, in particular the Binov method and the linear interpolation method. (Results and discussion) Formulas for calculating wind speed and active power for constructing power characteristics using the Binov method were given. Approaches to modeling the power characteristic and its approximation are described. At the same time, we took into account the features of power management systems, which are divided into active, passive and combined. The results of calculations were presented in tabular form, indicating that cubic polynomials cannot be used with passive and combined control systems due to a large approximation error; this indicates that common methods for determining power and output do not always give accurate results. (Conclusions) Several mathematical models used to analyze the power characteristics of wind power plants have been demonstrated. They have shown that they can be used to predict production for given sites with a known wind regime.

Methodology for lifetime characteristics assessment of mechanical equipment in nuclear power plants. Ageing management of NPP mechanical equipment

In the 20s of the twenty-first century many nuclear power plants around the world have reached the final years of their design lifetime. The technical aspects of Plant Life Extension (PLEX) activities involve tests, in addition to the routinely performed ones, of the materials and structures of reactor units, as well as the carrying out operability analyses. In relation to this, the absence of regulatory and methodological basis becomes apparent, in Bulgaria as well. In recent years, new approaches have been adopted for evaluation of lifetime characteristics of components. The algorithm implemented is based on the active mechanism of degradation of the mechanical properties of materials. This paper discusses PLEX stages and corresponding activities. A methodology has been developed to assess the lifetime characteristics of Nuclear Power Plant (NPP) components such as to suit the stages of plant life extension and long-term operation. The methodology consists of: 1) Equipment classification; 2) Identification of the major degradation mechanisms of the mechanical properties of materials; 3) Determining the degradation effects of the mechanical properties of materials; 4) Identification of methods to control degradation effects (ageing); 5) Development of methodologies for evaluation of the ageing effects.

СРАВНИТЕЛЬНЫЙ АНАЛИЗ ЭЛЕКТРОСТАНЦИЙ ПО НАБОРУ ИХ ХАРАКТЕРИСТИК

As a result of the analysis of various types of power plants, their disadvantages and advantages were identified in the article, the main quantitative and qualitative characteristics were determined, according to which different types of power plants can be compared. The following are selected as the main quantitative characteristics of power plants: unit cost; installed electric capacity; cost of electricity; utilization factor of installed power plant capacity; service life; efficiency, construction period and the area occupied by the power plant. Qualitative characteristics include: location, financial conditions, time and weather conditions, environmental friendliness, operation of power plants, utilization, carbon footprint. The most common types of power plants are also selected for comparison. The formulation of the problem was carried out and a comprehensive methodology was applied for selecting the best option for power plants based on the totality of its quantitative and qualitative characteristics, including methods of spectral analysis and hierarchy analysis. The combined use of spectral analysis and hierarchy analysis methods when choosing the best option for power plants allows to somewhat reduce subjectivity in decision-making, especially in conditions where a quick assessment of alternative options is required. Based on the methodology, integral quantitative estimates were obtained for each of the power plant options. According to the set of quantitative and qualitative characteristics, a ranked number of power plant options were obtained: nuclear power plants; thermal power plants; hydroelectric power plants; wind power plants; solar power plants. The best is a nuclear power plant. It was established that the greatest influence on the construction of the generalized ranked series of power plants according to the totality of quantitative and qualitative characteristics was exerted by: qualitative characteristics: location and financial conditions; quantitative: unit cost; installed electric capacity; cost of electricity; utilization factor of installed power plant capacity; service life; efficiency of power plants. The complex methodology can be used when making a decision on the choice of a combination of quantitative and qualitative characteristics of the best option and other technical systems.

Study of Peak-load regulation characteristics of a 1000MWe S-CO2 Coal-fired power plant and a comprehensive evaluation method for dynamic performance

In the new power system with large-scale grid-connection of intermittent new energy, the coal-fired power plants (CFPPs) play an important role of the ballast stone. In the process of grid-connection, CFPPs receive variable load instructions in real time. Higher peak-load regulation capacity and more flexible response for CFPPs are needed to provide a stable support to the power grid. The supercritical carbon dioxide (S-CO2) cycle has better variable working condition performance, which may improve the flexibility of the CFPPs peak-load regulation process. To explore the peak-load regulation characteristics of the S-CO2 CFPP, the variable load characteristics of a tri-compressions double-reheating intercooling (TC-DRH-IC) S-CO2 CFPP under five control methods are studied. Furthermore, a comprehensive evaluation method for the dynamic performance is proposed. First, the dynamic model of the TC-DRH-IC S-CO2 cycle with the modified isentropic efficiency of turbo-machineries, the unsteady flow heat transfer model of heat exchangers and a proportion integration differentiation (PID) controller is established. Second, the peak-load regulation characteristics of the TC-DRH-IC S-CO2 cycle are analyzed. A comprehensive evaluation method of dynamic control performance considering load change rate, dynamic response time, load rate variation range and cycle efficiency is proposed. Finally, the inventory control method is improved, which can improve the cycle efficiency at low loads. The results show that the improved inventory control method has a rapid practical load change rate of about 10%/min and a wide range of variable-load regulation from 10% to 100%. And the cycle efficiency is improved by 3.67% at 50% of the rated power. The S-CO2 CFPP has the potential of flexible peak-load regulation.

Energy Characteristics of Spherical and Cylindrical Solar Photovoltaic Power Plants on the Surface of Solar Houses

Energy Characteristics of Spherical and Cylindrical Solar Photovoltaic Power Plants on the Surface of Solar Houses

Optimum economic operation of coordinated power system based on turbulent water flow optimization

ABSTRACT Owing to increase in power demand, generation costs and environmental anxieties, renewable energy needs to be utilized to conserve energy and to reduce atmospheric pollutants. This study aims to present a new physics inspired metaheuristic algorithm, turbulent water flow optimization (TWFO) for scheduling the power generation of hydrothermal power systems incorporating with pumped storage units (PSU). TWFO is inspired by a natural phenomenon of action of whirlpools in water bodies. Different characteristics of power plants including valve point effect, transmission losses and multiple fuel sources are considered. A heuristic constraint handling mechanism is embedded in the proposed method to satisfy all the equality and inequality constraints. To exemplify the effectiveness of the TWFO, the proposed method has been validated on three coordinated power generation scheduling problems with different characteristics, and compared with particle swarm optimization, sine cosine algorithm, Harris hawks optimization, and other state-of-the-art techniques in the literature. Numerical results clearly signify that the TWFO is competent to obtain superior solutions than the other compared approaches, both in the quality of the solutions and the rate of convergence. Moreover, the fuel cost attained by the TWFO addressing PSU is lesser than that without addressing PSU. The proposed work ensures the economic operation of coordinated power system and increases the renewable energy utilization.

Regional and temporal variability in water use intensity for thermoelectric power plants in the contiguous United States

Water is crucial for power generation and understanding how much water is needed in the process becomes the key when ensuring water and energy security. Water use intensity has been estimated in the United States based on reported water use and electricity generation data. However, the water use intensity has been often estimated using a single year of records without comprehensive consideration of regional and seasonal variations. This study is thus focused on quantifying the water withdrawal intensity (WWI) and water consumption intensity (WCI), considering the power plant characteristics as well as regional and seasonal variations. The spatiotemporal variations are evaluated using the public records provided by the Energy Information Administration (EIA) of 234 thermoelectric facilities in the contiguous United States (CONUS) for the period 2010 to 2019. The median and range of WWI and WCI for CONUS are estimated for 26 cooling-engine combinations, which is valuable for assessing water security and energy security. The results demonstrate that WCI for power plants using cooling systems with cooling ponds is more variable regionally. The seasonal impact is more significant for recirculating cooling with natural draft systems. The median WCI for CONUS is 1.22 L/kWh. The results also confirm that facility, regional and seasonal factors are important and should be considered when estimating the water use by thermoelectric power plants.

Experimental research on the operation characteristics of solar chimney power plant combined with distillation (SCPPCD)

In this paper, a comprehensive test platform for solar chimney power plant combined with distillation (SCPPCD) that can realize water-electricity cogeneration was designed and built. Experimental research on SCPPCD was carried out under actual meteorological conditions to explore the system operation performance and the laws of freshwater production and power generation. The interaction mechanism between parameters such as seawater temperature, airflow temperature, temperature difference between seawater and solar still cover, freshwater yield and generated power was revealed. The results show that the daily water yield of solar stills decreases from the heat collector inlet to the chimney. Solar stills are recommended to be arranged in the area from collector inlet to the one-third radius of the collector. The high-water yield period occurs between sunset and 1–3 a.m., and it contributes most of the freshwater produced. Temperature difference is the main factor affecting water production during the rising period of freshwater production, and seawater temperature is the main factor affecting freshwater production during the decline period. The maximum temperature rise of airflow in the chimney is 17 ℃, and the temperature rise is maintained above 5 ℃ at night. The variation of generator power is similar to that of airflow temperature rise, and the maximum power reaches 0.71 mW. This study provides detailed experimental data and theoretical reference for future mathematical simulation research and commercial application of SCPPCD.

An integrated framework to assess climate change impacts on water use for thermoelectric power plants

Climate variability and change impact both water demand and water availability for power generation because of the interconnected relationship between water and thermoelectric power generation. To assess the impacts of climate change on water demand by thermoelectric power plants, this study developed a framework that integrates the characteristics of power plants and the results of the Integrated Environmental Control Model (IECM) and the General Circulation Model (GCM) to simulate the water demand. This study contributed a novel tool to assess climate change impacts on water demand based on local climate conditions. This framework was applied to thermoelectric power plants in Illinois to explore the water demand at daily, monthly, and annual temporal resolutions. The results demonstrated that water use is more sensitive at shorter timescales. Thus, it is important to examine the water-energy nexus at a finer temporal resolution. Results also indicated that water consumption is more sensitive to climate change than withdrawal; power plants with a wet cooling tower are more sensitive than ones with a once-through cooling system; and natural gas-fired power plants are more sensitive than coal-fired plants. The case study demonstrated the novel framework is capable to assess climate change impact on water demand of thermoelectric power plants at varying temporal resolutions and the framework is easily applicable to other parts of the world.