Power Plant Design Research Articles

Planning, Operation, and Design of Market-Based Virtual Power Plant Considering Uncertainty

The power systems of today seem inseparable from clean energy sources such as wind turbines (WTs) and photovoltaics (PVs). However, due to their uncertain nature, operational challenges are expected when WT and PV energy is added to the electricity network. It is necessary to introduce new technologies to compensate for the intermittent nature of renewable energy sources (RESs). Therefore, rationally implementing a demand response (DR) program with energy storage systems (ESSs) in a virtual power plant (VPP) environment is recommended as a way forward to minimize the volatile nature of RESs and improve power system reliability. Our proposed approach aims to maximize social welfare (SW) (i.e., maximization of consumer benefits while minimizing energy costs). Our method assesses the impact of the DR program on SW maximization. Two scenarios are examined, one with and one without a DR program. Stochastic programming theory is used to address the optimization problem. The uncertain behavior of WTs, PVs, and load demand is modeled using a scenario-based approach. The correctness of the proposed approach is demonstrated on a 16-bus UK generic distribution system. Our results show that SW and active power dispatch capacity of WT, PV, and ESS are fairly increased using the proposed approach.

Statistical Analysis of Wind Speed for Energy Potential Estimation in Bahir Dar, Ethiopia using Weibull Distribution Function

In this study, statistical analysis method has been used to assess the wind energy potential in Bahir Dar, Ethiopia. The analysis has been conducted based on the wind speed data collected by National Meteorological Agency (NMA) for the time span of 2006 to 2015. Weibull distribution function has been used as a statistical analysis model to fit the actual data via probability density function and cumulative density function. While estimating the Weibull parameters (shape and scale) in this wind energy potential assessment, three statistical methods, namely, the Graphical method (GM), method of moments (MOM) and standard deviation method (STDM) were used. Comparison of these statistical methods for the good fit was done by the analysis of the relative percentage error (RPE), root mean square deviation (RMSD), mean percentage error (MPE) and coefficient of variance (R 2 ) procedures. The regression coefficient (R 2 ) between the actual wind speeds and the Weibull predicted values ranged between 0.614-0.872. From this result, the method of moment (MOM) is the best efficient method for determining the value of shape and scale to fit the Weibull distribution curves. The annual mean wind speed in Bahir Dar is 6.86m/s, while the mean wind speed and the power density predicted by the Weibull probability density function are 5.97m/s and 11.37kwatt/m 2 respectively. The Weibull distribution function can be used with acceptable accuracy for prediction of wind energy output required for preliminary design and assessment of wind power plants. Keywords: Weibull distribution function, Probability density function, Cumulative density function, Graphical method (GM), Method of moments (MOM), Standard deviation method (STDM), Regression coefficient DOI: 10.7176/APTA/86-02 Publication date: October 31 st 2022

Investigation of the use of steam coil preheater to increase the net efficiency of thermal power plant

Conventionally, regenerative feed water heating is used to increase the net efficiency of a thermal power plant. In this method, extracted steam from the steam turbine is used to increase feed water temperature before feed water is sent to the boiler. Increasing the number of feed water heaters or the mass flow rates of extracted steam causes the net power plant efficiency to increase. However, there is a practical limit of the number of feed water heaters. Furthermore, there is an upper limit of the mass flow rate of extracted steam for a feed water heater. Consequently, there is an upper limit of the net power plant efficiency in a conventional design of power plant that relies only on regenerative feed water heating. In this paper, it is argued that the net power plant efficiency can be increased beyond this limit by using extracted steam to increase air temperature in steam coil air preheater before air enters the boiler. Models of boiler, steam turbine, and steam coil air preheater are used to demonstrate that the net efficiency of 50-MW power plant is increased by 2.32% due to the integration of steam coil air preheater having the area of 500 m 2 .

Determination of Angstorm Coefficients with curve fitting method by using Matlab Program

For the sustainable development of nations and to lessen the negative environmental effects of fossil fuels, more clean and renewable energy sources are now required. One of the most significant energy sources is solar energy. To utilize solar energy more efficiently in a particular area, it is crucial to be aware of the solar radiation levels. Furthermore, it's critical to accurately calculate solar energy for study into climate change, one of the biggest global challenges. Systems that utilize solar energy are frequently used nowadays to address the rising global need for energy. The high geographical and temporal resolution, global, diffuse, and direct sunlight data needed for the design and effective operation of solar power plants are now provided by satellite-based solar radiation predictions. In this work, satellite-based forecasting models were used to estimate diffuse solar radiation for the chosen region. In this study, the solar radiation irradiance values of the chosen region were estimated using the curve fitting approach. Angstorm coefficients were determined using the Matlab program for this investigation. Various statistical error analysis tests were used to evaluate how well the constructed model performed. The findings collected unequivocally demonstrate that the provided prediction models perform well.

Staff Training and Scientific Research Activities on the Basis of the Moscow Power Engineering Institute’s Renewable Energy Sources Educational and Experimental Site

The Institute of Hydropower and Renewable Energy Sources at the National Research University Moscow Power Engineering Institute is the only one in the Russian Federation that unites departments implementing educational programs in the areas of electric power engineering, electrical engineering, and power machinery design and construction, with placing focus on power and hydraulic engineering facilities. The need of training high-skilled personnel with broad knowledge in the design and operation of hydroelectric, wind and solar power plants has led to the development of a unique laboratory complex. The article gives a retrospective review of the process through which the Joint Laboratory of the Institute of Hydropower and Renewable Energy Sources was established.

Trading mode design for a virtual power plant based on main-side consortium blockchains

To stimulate the market vitality of distributed resources, the virtual power plant (VPP) has gradually transformed from a third-party profit organization to a service-oriented trading platform, and the transaction has shown a trend of decentralization. In this case, a new VPP trading mode is designed to solve the difficulties in multi-layer coordination and the lack of trust between market entities from the same layer. First, the consortium chain is combined with the multi-agent system to build a VPP internal transaction framework. In order to match the characteristic of the VPP with multi-layer market entities, the main-side chain governance structure is adopted to form data barriers and ensure the scalability of the transaction framework. Second, the existing consensus protocol is improved in accordance with the feature of VPP main chain, and the consensus reputation is introduced to maintain the operation efficiency of the blockchain. In order to improve the execution quality of distributed transactions and the VPP operation stability, the trading reputation closely related to the transaction result is introduced to constrain the trading behavior of aggregators, and a feasible bidding strategy is provided. Finally, the specific trading process of VPP based on the main-side chains is analyzed, and the main functions of smart contracts are designed in combination with internal market rules. The simulation results prove the feasibility and effectiveness of the proposed VPP trading mode.

Experimental and numerical investigation of the yaw moment of a downwind coned wind turbine rotor

AbstractThe yaw moment of wind turbine rotors has never been in the focus of wind turbine aerodynamics. With the increasing activities in the development of support structures for Floating Offshore Wind Turbines (FOWT), which passively align with the wind, the interest has shifted, as an accurate determination of the yaw moment is a crucial issue for a successful design of such power plants. A downwind coned rotor is a promising option to increase the yaw moment and therefore the self‐alignment capability of a passively yawing FOWT. Unfortunately, experimental and numerical studies on the estimation of the yaw moment of wind turbine rotors are rare. This is especially the case for downwind coned rotors. The aim of the present work is to provide reliable knowledge in this field. For this purpose, an extensive experimental and numerical study is carried out to determine the yaw moment of a downwind coned rotor. The results obtained from measurements in the wind tunnel are compared to those of simulations using a high fidelity RANS method and a blade element momentum theory (BEMT) method. BEMT is widely applied and can be considered as state of the art for predicting aerodynamic loads on FOWTs. However, the basic assumptions of BEMT do not account for a realistic influence of the skewed wake, so that the application of a correction method is necessary. In this work, the frequently used wake skew correction method based on Pitt and Peters is utilised and its influence on the calculation of the yaw moment is investigated. It is shown that this correction method yields a significant overprediction of the yaw moment in comparison to the measurements and consequently even impairs the quality of the simulation in this case. In contrast to this, the wake‐resolving RANS method is capable of reproducing the measurements with reasonable accuracy and provides valuable insight into the role of the lateral force for the measurement of the yaw moment.

CONCEPTUAL ISSUES ON ENSURING THE RELIABILITY OF A FORCED DIESEL ENGINES PISTONS DURING A GIVEN RESOURCE

The design of modern power plants involves conducting calculation studies on the compliance of the structure with the established parameters of reliability and resource provision. However, there are cases when the structure, which according to the calculations is operational, fails in operation even before approaching the limit of its resource, and sometimes even at the beginning of operation. Such cases occur due to the fact that the materials used in the construction work at the limit of their strength, and sometimes crossing it, because in recent years there has been a constant increase in the capacity of power plants while maintaining the requirements for their resource. Thus, it becomes necessary to supplement the models to take into account a complex of factors affecting the physical and parametric reliability of the structure. The paper analyzes publications and sets a task for research, analyzes the main problems of loss of physical and parametric reliability of the piston, as one of the most thermally loaded structural elements, analyzes the thermally stressed state of characteristic critical zones of the piston, shows ways to ensure the reliability of pistons through adjusting the temperature state of structures. Based on the results of the analysis, the model for predicting the reliability of heat-stressed zones of parts of the cylinder-piston group was improved, the corresponding scheme of the integrated software complex was proposed, and the requirements for its application were formulated. The basis of the approach is the application of the criterion of physical reliability of structures and two criteria of their parametric reliability - from wear of friction pairs and not exceeding the creep limit of the material. This work makes it possible to obtain a design that is guaranteed to satisfy the requirements for physical and parametric reliability. The need for further work in the direction of expanding information about the properties of materials used in structures is also shown.

Perancangan Automatic Transfer Switch (ATS) Pembangkit Listrik Hybrid Panel Surya dan Generator untuk Bagan Apung

Design of Automatic Transfer Switch (ATS) Hybrid Solar Panel and Generator Power Plant for Floating Fishnet. Fishing business with floating nets has great benefits for small-scale fisheries. The development of the floating fishnet is quite good in Indonesia, especially in terms of production and fishing production. The problem of lack of lighting sources is the main problem faced by fishermen on the floating fishnet because the source of electricity used usually comes from conventional power plants (gasoline generators). Hybrid power plant is one of the power plant innovations that can take advantage of the use of renewable energy and become a solution to produce alternative energy on a floating fishnet. Automatic Transfer Switch (ATS) of hybrid power generation system is designed for automatic switch when the main power generation system has reached the specified voltage limit of 11V and is also designed for automatic switch when the backup power generation system has reached the specified voltage limit of 10V. The results obtained indicate that the main power generation source supplies 240W of load for 44 minutes with an average consumption current of 0.182A, while the backup power source supplies 240W for 28 minutes with an average current of 0.177A.

Availability assessment of a nuclear reactor limitation system by a Timed Petri Net

The constant evolution of instrumentation and control systems (I & C) of nuclear power plants requires a robust reliability assessment, due to the constant interaction between different systems that are demanded under normal operating, transient or accident conditions. Several methodologies have been developed to model the reliability of digital I & C systems and their dynamic behavior to better model the interaction between several equipment. In nuclear power plant design, many I & C systems work together according to priority scales and safety importance. In some designs, a Reactor Limitation System (RLS) has an important function to preserve equipment during transients and because of this, it is classified as safety related. After discussing pros and cons of the available tools for the analysis (including failure mode definition and quantitative data gathering), this paper evaluates the application of a timed Petri net to simulate RLS functions of an analog I & C design with timing on transitions. The reason for doing so is because it is possible in this model to represent the response time of components, maintenance time and periodic test behavior besides the interactions mentioned above.The results for three scenarios modeled by a timed Petri net indicate an RLS availability between 87.38% and 99.99% based on pressure transmitter, pressurizer spray valves and heater features (like component response time, failure characterization, maintenance and periodic test). The results of this work indicate that a timed Petri net can better evaluate the model of pressurizer pressure control by an RLS classified, actually, as an analog system that can be digitalized around the plant lifetime. Two importance risk metrics, namely, Risk Reduction Worth (RRW) and Risk Achievement Worth (RAW) were applied to identify the contributions for safety function failure of each type of RLS component.

Kinetic ballooning modes as a constraint on plasma triangularity in commercial spherical tokamaks

To be economically competitive, spherical tokamak (ST) power plant designs require a high β (plasma pressure/magnetic pressure) and sufficiently low turbulent transport to enable steady-state operation. A novel approach to tokamak optimisation is for the plasma to have negative triangularity, with experimental results indicating this reduces transport. However, negative triangularity is known to close access to the ‘second stability’ region for ballooning modes, and thus impose a hard β limit. Second stability access is particularly important in ST power plant design, and this raises the question as to whether negative triangularity is feasible. A linear gyrokinetic study of three hypothetical high β ST equilibria is performed, with similar size and fusion power in the range 500–800 MW. By closing the second stability window, the negative triangularity case becomes strongly unstable to long-wavelength kinetic ballooning modes (KBMs) across the plasma, likely driving unacceptably high transport. By contrast, positive triangularity can completely avoid the ideal ballooning unstable region whilst having reactor-relevant β, provided the on-axis safety factor is sufficiently high. Nevertheless, the dominant instability at long wavelength still appears to be the KBM, though it could be stabilised by flow shear.

Process design and comprehensive comparison of coal- and biomass-fired oxy-combustion power plant

Oxy-combustion is a promising option to achieve large-scale CO2 emission reduction associated with coal-fired power plants. However, its commercial application is greatly restricted due to the large efficiency penalty and high cost of electricity. In this paper, a novel 1000 MW single reheat oxy-combustion power plant is proposed by adopting the heat capacity flowrate matching method to reduce irreversible loss and increase heat recovery of the overall power plant. A quantitative comparison of novel coal- and biomass-fired cases is conducted. The results show that the net electric efficiency of the novel oxy-combustion power plant improves by 0.85% points with a 1.0% points enhancement in the exergy efficiency and a 1.1 $/(MW·h) reduction in the cost of electricity compared with the reference case. When biomass is selected as the fuel, the net electric efficiency of the novel system increases by 1.1% points, and 4.0 MtCO2 is removed from the atmosphere annually. Exergy analysis reveals the energy-saving mechanism of the novel system. Economic analysis indicates that total investment can be recovered within 1.8 years. This work provides an efficient and economic scheme for the design of oxy-combustion power plants.

PROGRAM KEMITRAAN MASYARAKAT INOVASI RESERVE ENERGY HYBRID (WIND TURBINE, SOLAR CELL DAN GENERATOR) DI PEMERINTAH DESA TEGAL SAMBI KABUPATEN JEPARA

This service activity aims to assist service partners in optimizing the surrounding natural resources and financial efficiency of village government institutions. In addition, this activity also aims to help the central government in order to reduce the use of fossil fuel electrical energy by maximizing the use of solar and wind heat which is very abundant in the village of Tegalsambi Tahunan Jepara. To realize the purpose and purpose of holding this service activity, the team provided several solutions which include the following things 1) making a hybrid solar cell power plant design that will be placed in the Tegal Sambi village hall as an effort to efficiently use PLN electricity so that it is expected to reduce the cost of electricity use at the village service office. This activity is made with five stages, namely analyzing the needs of energy use, designing solar cell power plants, socialization to village governments and communities, installation and installation of solar cell power plants, as well as assistance in use and maintenance. 2) manufacture and installation of wind power plants (wind turbines) on public street lighting (PJU)

Operational Planning and Design of Market-Based Virtual Power Plant with High Penetration of Renewable Energy Sources

Renewable energy sources (RESs) are becoming more prevalent as a source of clean energy, and their integration into the power market is speeding up. The fundamental reason for this is the growing global concern about climate change. However, their weather-dependent and uncertain nature raise questions about grid reliability particularly, when photovoltaics (PVs) and wind turbines (WTs) technologies are used. As a result, rationally managing Energy Storage Systems (ESSs) under the virtual power plant (VPP) setting is being encouraged as a way of minimizing the impact of the uncertain nature of renewable energies. A VPP is comparatively a new concept that aggregates the capacities of dispatchable and non-dispatchable energy sources, electrical loads, and energy storage systems for the purpose of improving energy supply and demand imbalance. It enables individual consumers and producers to participate in the power markets. In this study, a new market-based (MB)-VPP operational planning model is designed and developed with the aim to evaluate the optimal active power dispatched by (WT, PV, and ESS) operating in the day-ahead power market to maximize the social welfare (SW) of the market. SW can be described as the maximization of the consumer’s benefit function minus the cost of energy generation. The optimization process was carried out by using a scenario-based approach to model the uncertainties of renewable energy sources (i.e, WTs & PVs) and load demand. The proposed model and method performance is validated by simulation studies on a 16-bus UK generic distribution system (UKGDS). The simulation results reveal that the proposed approach maximizes overall system social welfare. The capacity of total active power dispatched by (WT, PV, and ESS) has a positive impact on the VPP profit maximization. This empirical study could be used as a reference baseline model for other energy services providers interested in conducting similar research in the future.

Improvement of conventional design of lignite-fired thermal power plant by integrating steam-air preheater and flue gas dryer

The conventional design of thermal power plant uses regenerative feed water heating to increase the overall power plant efficiency. This method is limited by the number of feed water heaters and the amount of extracted steam supplied to each feed water heater. It is proposed in this paper that the improvement of the conventional design is possible by integrating steam–air preheater and flue gas dryer into the power plant. Extracted steam is used to increase air temperature in steam–air preheater before air is sent to boiler. Due to increased air temperature at the boiler inlet, flue gas temperature at the boiler outlet is increased. Flue gas dryer is used to decrease exhaust flue gas temperature to 150 °C. In doing so, the fuel moisture content is reduced, which results in increased boiler efficiency and increased overall power plant efficiency. A case study of the design of a 500-MW lignite-fired subcritical power plant is considered to demonstrate that the integration of steam–air preheater and flue gas dryer increases the overall power plant efficiency. Furthermore, this integration is shown to be economically justified because of a low value of levelized cost of electricity.

STUDY OF SAFETY FOR UNDERGROUND NPP

STUDY OF SAFETY FOR UNDERGROUND NPP. Human growth has consequences for land use. The construction of facilities and industries to meet human needs makes the availability of land for natural ecosystems, and agriculture tends to decrease. One land use in the energy sector includes constructing a Nuclear Power Plant (NPP). Therefore, NPP developers have currently developed several designs of nuclear power plants with small sizes, namely Small Modular Reactor (SMR), Micro Modular Reactor (MMR), and underground NPP. In addition to saving space, underground nuclear power plants have several advantages, namely increased security, strengthened containment, and protection from external events. On the other hand, safety issues must still be the main focus of this NPP design. Based on Government Regulation 54 of 2012, safety is a provision that must be met by business entities wanting to carry out construction, operation, and decommissioning. Therefore, this paper is prepared to elaborate on what must be considered for this NPP design. The study was carried out based on the design catalog of the Super-Safe, Small, and Simple Reactor (4S) nuclear power plant developed by Toshiba and combined with other references related to underground building structures. The results of the study found that several things must consider for the design of an underground NPP hydrology, soil properties, the possibility of accidents due to debris, maintenance, and response to nuclear emergencies. Keywords: NPP, Underground NPP, Safety, NPP Design

Advances in Process Modelling and Simulation of Parabolic Trough Power Plants: A Review

The common design of thermal power plants is fundamentally oriented towards achieving a high-process performance, with market demands necessitating enhanced operational stability as a result of ongoing global support for renewable energy sources. Indeed, dynamic simulation represents one useful and cost-effective choice for optimizing the flexibility of parabolic trough power plants (PTPP) in a range of transient operating conditions, such as weather changes, resulting again in variations of the output load as well as varying start-up times. The purpose of this review is to provide an overview of steady-state and dynamic modelling for PTPP design, development, and optimization. This gives us a greater opportunity for a broad understanding of the PTPPs subjected to a variety of irradiance solar constraints. The most important features of the steady-state and their uses are reviewed, and the most important programs used in steady-state modelling are also highlighted. In addition, the start-up process of the plant, thermal storage system capacities and response dynamics (charging and discharging modes), and yearly electricity yield can be analyzed using dynamic modelling. Depending on the dynamic simulation, specific uses can be realized, including control loop optimization, load estimation for critical in-service equipment, and emergency safety assessment of power plants in the event of an outage. Based on this review, a detailed overview of the dynamic simulation of PTPP, and its development and application in various simulation programs, is presented. Here, a survey of computational dynamic modelling software commonly applied for commercial and academic applications is performed, accompanied by various sample models of simulation programs such as APROS, DYNAMICS, DYMOLA, and ASPEN PLUS. The simulation programs generally depend on the conservation equations of mass, momentum, species, and energy. However, for the equation of equilibrium, specific mathematical expressions rely on the basic flow model. The essential flow models involved, together with the basic assumptions, are presented, and are supplemented through a general survey covering popular simulation programs. Various previous research on the dynamic simulation of the PTPP are reviewed and analyzed in this paper. Here, several studies in the literature regarding the dynamic simulation of the PTPP are addressed and analyzed. Specific consideration is given to the studies including model verification, in order to explore the effect of modelling assumptions regarding the simulation outputs.

Design of a stand‐alone 1000‐kW biogas power plant from codigestion of organic waste and microalgae grown in a tubular photo bioreactor at Bomaka‐Buea

The cover image is based on the Research Article Design of a stand-alone 1000-kW biogas power plant from codigestion of organic waste and microalgae grown in a tubular photo bioreactor at Bomaka-Buea by Fonge Emmanuel Nchindia et al., https://doi.org/10.1049/rpg2.12524.

Review of Design Extension Conditions Experiments and Analyses for Non-degraded Core

The second generation nuclear power plants were designed and built to withstand without loss to the systems, structures, and components necessary to ensure public health and safety during design basis accidents (DBAs). In the transient and accident analysis the effects of single active failures and operator errors were considered. There are also accident sequences that are possible but were judged to be too unlikely and therefore were not fully considered in the design process of second generation reactors. In that sense, they were considered beyond the scope of design-basis accidents that a nuclear facility must be designed and built to withstand. Such accident sequences have been analysed in the past to fully understand the capability of a design. The requirements to analyse such sequences for existing reactors have been introduced after Fukushima Dai-ichi accident. In 2012 the design extension conditions (DECs) were introduced in the International Atomic Energy Agency (IAEA) requirements for the design of nuclear power plants (NPPs). Western European Nuclear Regulators Association (WENRA) requirements of existing reactors for DEC were introduced in 2014. The purpose of considering DEC is to further improve safety by enhancing the plant’s capability to withstand the conditions generated by accidents that are more severe than DBAs. This concept by IAEA and WENRA (WENRA definition of DEC is consistent with IAEA definition from 2012, in which DEC with prevention of core melt is called DEC A) is not completely new, since some multiple failures have already been considered in the design of existing reactors, for example anticipated transients without scram and station blackout. The research for beyond design basis accidents with non-degraded core (i.e. DEC A) for existing reactors has been already done in 80’s and 90’ of the previous century. The purpose of this paper is to review that research. The tests performed include total loss of feedwater, station blackout, small break without high pressure safety injection, steam generator tube rupture with no high pressure safety injection etc. Besides review of experiments performed on integral test facilities, examples of DEC A tests, which have been analysed at Jožef Stefan Institute using RELAP5 or TRACE computer code in the last three decades, will be presented too.

Methodology for Assessing Meteorological Observation Data to Account for Wind Potential in The Design of a Wind Power Plant

The development of clean renewable energy sources is a strategic task to ensure the balance of energy supply to territories. When implementing a policy of reducing dependence on or abandoning fossil fuels, the use of renewable energy sources is an obvious competitive solution. And for territories remote from power supply networks, the development of renewable energy sources is generally the only alternative. Wind energy is increasingly being used to generate electricity. In this sense, accurate accounting of the influence of wind potential on the energy balance is the basis of energy-saving architecture. From a thermodynamic point of view, wind is a high-quality source of energy. Its high efficiency makes it possible in principle to convert into other types of energy. However, the wind energy flow is unstable – the performance of wind power plants is due to their extremely high sensitivity to the conditions of their location. In this situation, the reliability of the initial data on wind energy resources is a criterion of paramount importance. Therefore, the development of a methodology for evaluating data from long-term meteorological observations of wind speed and direction is of important empirical importance. To design a wind power plant, it is not enough to enter ready–made data on the value of specific power and specific wind energy in the territory into economic calculations - the data deviation is too large. It is necessary to calculate the technical potential of the wind power plant for each prospective location option. Both the approach to accounting for wind potential and the approach to scaling the data of the observation station to remote territories ensure the reliability of the initial data for the design of a wind power plant. The proposed methodology highlights all these aspects and offers an algorithm for evaluating the data of long-term ground-based meteorological observations on the territory of Russia.