Power Plant Equipment Research Articles

Neural network for predicting operating modes and calculating energy characteristics of steam turbine plants

The article describes the results of work on the creation of neural networks calculating the technical and economic parameters of all possible modes of operation of a thermal turbine unit with a steam turbine of type PT-60-130/13. In accordance with the objectives set, recommendations for the preparation of training data samples are formulated. The input and output parameters of the condensing and heating modes of operation of the steam turbine are determined. The results of research on determining the most optimal architecture of neural networks for calculating the energy characteristics of steam turbine plants of the heating type are presented. The results of calculations of the mean squared errors of neural network predictions from the results of calculations performed using a verified object-oriented model of a PT-60-130/13 turbine unit are tabulated.Graphs of the dependence of the specific heat consumption for the generation of electrical energy on the power of a PT-60-130/13 turbine unit for condensation and heating modes of operation using neural networks are plotted. The conclusion is formulated about the possibility of using neural networks for the development of energy characteristics and regulatory documentation on fuel use of equipment of thermal power plants.

Steam generator efficiency optimization under uncertainty through multi-fidelity modeling

The steam generator is an essential equipment in power plants, and understanding its behavior with the aid of mathematical models allows for improved decision-making aiming toward better efficiency. Well-calibrated models can help identify new operating conditions that lead to efficiency enhancement. Unfortunately, due to the complexity of steam generators, computationally efficient models based solely on energy-mass balance usually present limiting simplifications. Alternatively, computational fluid dynamics can solve reacting flow phenomena but require a great amount of computational time. Purely data-driven models often extrapolate poorly as they do not necessarily contain the physical equations that drive the system’s behavior. In this scenario, the multi-fidelity approach is an attractive solution because it combines physics-grounded representation with a low computational footprint and allows for mapping the efficiency of the steam generator considering uncertainty propagation. This paper presents a multi-fidelity model that simulates the efficiency of a steam generator from the PECÉM power plant. The model is assembled by the sum of two Gaussian processes, trained using one high-fidelity and one low-fidelity dataset. The high-fidelity dataset is formed by the observed operation of the actual power plant at varying operating conditions. These same operating parameters are the input for the energy-mass balance model built using the EBSILON software to generate the low-fidelity dataset. The observed efficiency of the PECÉM power plant ranged from 82.89% to 84.37%, with a mean value of 83.58%. The resulting multi-fidelity model presents a root mean square error of 0.19%, which is six times lower than the error obtained by the energy-mass balance model. This model is then used for global sensitivity analysis and robust optimization. A Pareto front mapping expected efficiency and its confidence level is built by exploring not yet experimented operational points. Finally, data clustering allowed the identification of efficiencies around 86%, which adds 1.63% to the power plant’s maximum level.

Ведение ВХР с применением реагентов ВТИАМИН на ТЭЦ с сезонным режимом работы

The main equipment of the thermal power plant (TPP) includes a E-120-7.0-500GM steam boiler produced by LLC “Belenergomash – BZEM” with a single-stage evaporation circuit. The operating mode of the thermal power plant has seasonal characteristics. During the period of February to the end of August the equipment is stopped as a reserve. Dosing of AMINAT PK-3 does not provide the required pH level in steam and feed water, so the reagent for water-chemical regime and preservation has been substituted with VTIAMIN KR-33. The complex reagent VTIAMIN KR-33 ensures both the maintenance of the required quality indicators of the coolant along the path and promotes the formation of a protective barrier film on the internal heating surfaces. To check water-chemical regime, the existing automatic chemical control system has been updated. Panels have been installed for automatic chemical control of pH value, electrical conductivity of direct and H-cationized samples. The filter material has been replaced and the mechanical filters have been connected. The first stage of the filter has been replaced, the second stage of the filter and final purification filters Н-OH have been installed. The authors have demonstrated the possibility to use boilers with seasonal operating modes and measuring the electrical conductivity of cooled water and steam samples as a chemical control of water chemistry. It is found out that dosing the VTIAMIN KR-33 reagent with periodic dosing of the VTIAMIN D-8 reagent into the boiler water prevent the precipitation of hardness salts and other impurities coming with the return condensate. Analysis of the indicators of the water chemistry regime at the thermal power plant when dosing the VTIAMIN KR-33 reagent at two points has shown that the pH value of the feed water is in the range of 8,8–9,0 and the indicators of the water chemistry regime in terms of the content of iron, silicic acid and sodium are also within the norm limits. The composition of the reagents is selected. Flexibility of water chemistry management is ensured. It has been shown that the dosage of the amine-containing reagent VTIAMIN neutralizes the negative effects of aggressive gases (carbon dioxide and oxygen) due to their binding and the formation of a protective film of the magnetite-amine type on heating surfaces. Introduction of the water chemical regime when the equipment is stopped as a reserve does not require additional preservation measures.

Technical Language Processing of Nuclear Power Plants Equipment Reliability Data

Operating nuclear power plants (NPPs) generate and collect large amounts of equipment reliability (ER) element data that contain information about the status of components, assets, and systems. Some of this information is in textual form where the occurrence of abnormal events or maintenance activities are described. Analyses of NPP textual data via natural language processing (NLP) methods have expanded in the last decade, and only recently the true potential of such analyses has emerged. So far, applications of NLP methods have been mostly limited to classification and prediction in order to identify the nature of the given textual element (e.g., safety or non-safety relevant). In this paper, we target a more complex problem: the automatic generation of knowledge based on a textual element in order to assist system engineers in assessing an asset’s historical health performance. The goal is to assist system engineers in the identification of anomalous behaviors, cause–effect relations between events, and their potential consequences, and to support decision-making such as the planning and scheduling of maintenance activities. “Knowledge extraction” is a very broad concept whose definition may vary depending on the application context. In our particular context, it refers to the process of examining an ER textual element to identify the systems or assets it mentions and the type of event it describes (e.g., component failure or maintenance activity). In addition, we wish to identify details such as measured quantities and temporal or cause–effect relations between events. This paper describes how ER textual data elements are first preprocessed to handle typos, acronyms, and abbreviations, then machine learning (ML) and rule-based algorithms are employed to identify physical entities (e.g., systems, assets, and components) and specific phenomena (e.g., failure or degradation). A few applications relevant from an NPP ER point of view are presented as well.

Multiobjective optimization of laser welding parameters for P92 steel based on MFO/MOEAD-Kriging

P92 steel is used in steam equipment of thermal power plants and nuclear power plants. It needs to withstand high temperature and high pressure during service, so high-quality welds are required. Laser welding can easily obtain good weld quality and reduce the probability of coarse grains and welding defects in the heat-affected zone. Post-weld deformation, residual stress, and weld hardness are important indexes for evaluating weld quality, which largely depends on the combination of laser welding process parameters. The multiobjective optimization methods of moth-flame optimization (MFO) and multiobjective evolutionary algorithm based on decomposition under the Kriging model were compared in this research. It was found that the MFO algorithm has a faster optimization speed and better overall effect. The Optimal Latin hypercube sampling method was used to design the simulation test. The welding seam-forming process was simulated by the SYSWELD software. The Kriging model was used to make the nonlinear relationship between the process parameters and the weld quality indexes significant. A new data set was designed to evaluate the accuracy of the model. On this basis, the efficiency of the combination of process parameters optimized by the two algorithms was compared. The simulation and experimental results were in good agreement with the multiobjective optimization results of the MFO. In the experimental verification, the optimized weld quality was analyzed from the aspects of microstructure and mechanical properties. The results showed that the multiobjective optimization method quickly and effectively reduces the probability of weld quality defects in actual welding, thereby improving weld quality. This multiobjective optimization method provides valuable research ideas for engineering research and development to effectively shorten its development cycle.

Predictive maintenance system for high-end equipment in nuclear power plant under limited degradation knowledge

To ensure the safe operation of high-end equipment, the three-stage maintenance strategy comprising unplanned shutdown, temporary shutdown, and scheduled shutdown is currently employed in nuclear power plants. However, this strategy hinders the acquisition of degradation knowledge (run-to-failure data or degradation mechanism), thereby impeding the application of traditional predictive maintenance systems. Hence, the responsibility for determining the maintenance stage primarily lies with experienced field engineers, and an incorrect decision could potentially result in an unplanned shutdown. To this challenge, we integrate the three-stage maintenance strategy and prognosis methods to form a predictive maintenance system for nuclear power plants. The system framework is first established, and prognosis methods, including sensor selection, degradation trend prediction for short-term prognosis, and remaining useful life (RUL) prediction for long-term prognosis, are then developed under limited degradation knowledge. Finally, the system is deployed in the circulating water pump of a nuclear power plant utilizing an Internet of Things (IoT) architecture. An industry case study verifies that the proposed system can provide decision-making support and further achieve predictive maintenance for high-end equipment in nuclear power plants.

An efficient authentication protocol with privacy-preserving for virtual power plant

As an important manifestation of the current development and transformation of the world’s power and energy industries, the virtual power plant is an important foundation for optimizing the layout of energy resources. However, since there are many open channels in the virtual power plant, adversaries can implement eavesdropping, replay, impersonation, forgery, and other attacks to access the virtual power plant, and even publish false data in the virtual power plant to disrupt the operation of the virtual power plant. In addition, it is easy for an adversary to deduce key information such as the layout of virtual power plant equipment through the identity of the device. In this context, to ensure the security and privacy of devices when accessing the platform, in this paper, we propose an efficient authentication protocol based on the elliptic curve cryptography and zero-knowledge proof, which requires only two information exchanges. Security analysis shows that the proposed protocol can meet security features such as mutual authentication, key agreement, perfect forward secrecy, and device anonymity. Performance analysis indicates that the proposed protocol achieves a reasonable balance between computational and signaling overhead, and it is more suitable for achieving efficient device authentication and privacy protection in virtual power plants.

Unbalanced force analysis on valve core clamping in hydraulic spool valves

Hydraulic systems are widely used in nuclear power plant equipments. The reliability and stability of hydraulic systems can be seriously impacted by the valve core clamping resulting from unbalanced forces. This paper investigates the unbalanced force characteristics of hydraulic spool valve cores to identify the mechanisms behind such failures. Numerical models are established for hydraulic spool valve cores using sliding mesh technology with varying control face structures and space angles between the inlet and outlet, which are validated by experiments. The turbulent flow is modeled using the RNG k-ε model. Simulation results reveal that larger openings weaken the unbalanced force distribution while the larger inlet flow rates exacerbate the unbalanced force distribution, and control face structures significantly impact force distribution by altering the throttling effect of the throttle orifice. Furthermore, the impact of the space angles between the inlet and outlet is little compared with other parameters. These findings provide a reference for designing and optimizing hydraulic spool valves, contributing to higher reliability and stability of hydraulic systems.

Boiler Combustion Adjustment and Economic Operation Affect Boiler Combustion Factors

Thermal power generation, as the most stable power output in China, plays a rather crucial role in the construction of China's economy. The most important power generation equipment of thermal power plant is the boiler, only good control of the boiler operation of the power plant, in order to better enable it to participate in the power generation work. Combined with the Linfen Thermal Power Co., Ltd. related boiler unit operation status, combustion adjustment optimisation content analysis, give the corresponding recommendations, so as to make the boiler operation more stable, safe, environmentally friendly, power plant power generation to make the corresponding contribution.

Relevance of monitoring residual stresses and the need to reduce them

The objective of the study is to show the significant impact of taking into account the actual values of residual stresses on the strength and resource of safe operation of nuclear power facilities. Generally accepted approaches of strength physics and fracture mechanics were used to determine strength and service life. The degree of influence of residual stresses on the strength and service life of pipeline elements in the case of a cyclically acting load, under static load, when there is a danger of brittle fracture, and in the case of corrosion is investigated. The objects of the study were pipelines of nuclear power plants. It is noted that the current state of science and technology has made it possible to create a technique for non-destructive testing of mechanical stresses acting in metal structures based on the use of the acoustoelasticity method. Currently, on the basis of this method, a method for measuring residual welding and installation stresses in pipelines has been developed and certified for use in the field of atomic energy use. The measurement technique provides for the determination of membrane and bending stresses in annular sections located on rectilinear sections of pipelines. The values of stresses in the structural elements of pipelines and residual welding stresses in the deposited metal of welded joints are determined using ratios based on the use of the balancing principle. The relevance of introducing into the procedure for monitoring the technical condition of pipelines and equipment of nuclear power plants the procedure for determining the actual level of residual stresses, which significantly increases the reliability of the assessment of their strength and service life, is shown. It is proved that in order to implement the procedure for determining the actual level of residual stresses, it is necessary to use a non-destructive testing system for residual welding and installation stresses using the acoustoelasticity method based on a measurement technique that allows determining the actual values of residual stresses with established error characteristics.

Integrating Parabolic Trough Solar Fields Into Computerized Maintenance Management Systems

Computerized maintenance management systems for power plants are not well suited for application in solar fields. They work well for tracking maintenance requirements on the hundreds or even thousands of pieces of equipment in conventional power plants, but they do not work as well tracking the maintenance requirements on hundreds of thousands of identical pieces of equipment found in a solar field. A database application, known as a field status program, is being developed for tracking the maintenance and status of collectors and components in parabolic trough solar fields as a complement to the computerized maintenance management system. This system, patterned after a similar system developed by the KJC Operating Company in the 1990s, provides a valuable tool for the O&M of parabolic trough solar fields. This paper describes the development and application of the tool and the new expanded capabilities that are being added to further enhance the O&M of solar fields.

Application of ensemble learning approach on anomaly detection of a dual induced draft fan system

Intelligent monitoring of thermal power plants has been receiving growing interest. As one of the promising technologies in intelligent monitoring, machine learning-based fault detections for auxiliary equipment in the thermal power plant have been widely investigated. In this work, we constructed normal behavior models to predict the current of a dual-induced draft fan system by gradient-boosting tree regression. For anomaly detection, we evaluated the residual by calculating the mean value and meanwhile added a control boundary based on statistical analysis. As a result, we successfully identified the abnormal fan in the dual-induced draft fan system and assisted in the schedule of maintenance work.

Diagnosis and green emission reduction of power plant equipment based on machine learning classification algorithm

Diagnosis and green emission reduction of power plant equipment based on machine learning classification algorithm

Design Process and Advanced Manufacturing of an Aquatic Surface Vehicle Hull for the Integration of a Hydrogen Power Plant Propulsion System

This article presents the design and manufacturing of a hydrogen-powered unmanned aquatic surface vehicle (USV) hull. The design process comprised three stages: (1) defining the requirements for a preliminary geometry, (2) verifying the hydrodynamic hull performance using computational fluid dynamics (CFD) simulations, and (3) experimentally validating the hydrodynamic hull performance and CFD analysis results through experimental fluid dynamics in a calm water towing tank. The manufacturing process utilized additive manufacturing technologies, such as fused granular fabrication and selective laser sintering, to produce the hull and other components, including the propeller and the rudder; thermoplastic materials with carbon fiber reinforcement were employed. The experimental results demonstrate that the optimized trimaran hull exhibited low hydrodynamic resistance (7.5 N), high stability, and a smooth flow around the hull (up to 2 m/s). The design and manufacturing of the USV hull met expectations from both hydrodynamic and structural perspectives, and future work was outlined to integrate a power plant, navigation system, and scientific equipment.

DESIGN OF HIGHLY EFFICIENT WATER PASSAGE OF PUMP-TURBINE

The problem of the need to develop renewable energy sources as a way to save the energy supply and energy independence of Ukraine by changing the consumption of carbohydrates is considered. It is shown that the development of Ukrainian renewable energy must occur in parallel with the development of energy storage systems and balancing of the energy system. The most effective system for storing energy and balancing the energy system is pumped storage power stations (PSPS). The work shows that the design of a highly effective equipment of a hydroelectric power plant depends on the correct selection of the element geometry of the pump-turbine water passage. Therefore, it is possible to ensure the necessary level of energy characteristics of hydraulic equipment. A method of dimensionless average parameters was established, which allows even at the initial stages of designing new reversible hydraulic machines to determine the optimal geometry of the watter passage elements. This method showed good results during the numerical research of Francis hydraulic turbines at a wide range of heads, as well as reversible hydromachines at heads of 300–500 m. Using expressions that establish the connection of hydrodynamic characteristics with dimensionless complexes, three variants of the flow part of the high-pressure pump-turbines (ORO500) were investigated. Based on the obtained results, a significant influence of the geometry on the hydraulic indicators of the machine was noted. The distribution of energy losses in the inlet, blade system and outlet was analyzed. The greatest energy losses occur in the inlet of the pump-turbines. To increase the energy and kinematic indicators of the ORO500 pump-turbines, the geometry of the feed elements, as well as the spiral casing and stator, was changed. Variants for improving the parameters in the elements of the supply of the water passage of the pump-turbine are proposed.

Optimal selection of parallel pumps running as turbines for energy harvesting in water transmission lines considering economic parameters

The need for energy is growing due to concerns about development and well-being, but the traditional methods of energy production harm people and the environment. This impact can be reduced by using renewable energy sources like hydropower. Since the cost of electromechanical equipment in small hydroelectric power plants accounts for a large percentage of the capital cost, applying the pump as turbine (PAT) is recommended. In this research, an effort has been made to select the optimal arrangement of PATs for a water transmission line without the need for control systems. The selection optimization process involves selecting the model of the pump as turbine and the number of turbines in parallel simultaneously. The optimization process relies on economic parameters, aiming to maximize the Net Present Value (NPV) of the power plant. In addition, the financial analysis of the project has been carried out. As a first step to achieve this objective, a database including single and double-suction pumps based on available pumps is needed. To cover a wider range of heads and flow rates, impeller trimming relationships for the pumps are considered. The Brute-Force algorithm has been used for the optimization process and two different objective functions (OF) have been investigated. First, it is based on economic optimization, and the NPV function is used as the OF; then, the Multi-Criteria Decision Making (MCDM) method is used as the second OF. The case study of this research is a water transmission line between two cities in Iran. A MATLAB code has been developed to perform all the steps of this study. The results demonstrate that by considering impeller trimming for pumps in the database and using NPV as OF, the number of pumps used for the power plant decreased from 12 to 6 and the capital cost decreased by about 10%. By implementing impeller trimming, the NPV and energy production of the PAT power plant are increased. Comparing the two desired objective functions leads to the recommended appropriate OF for applications. It is worth mentioning that the harvested energy from this water transmission line is about 9 GWh/year. The economic analysis results show that the PAT power plant payback period (PP) for this water transmission line is less than one year.

Development of a device for the utilization of drilling rig heat

Drilling wells is an energy-intensive process. Due to the specifics of drilling operations, the distance from industrial centers and their power systems, and the mobility of equipment, energy supply experience does not always allow its application to other industries. When drilling, along with electricity, large quantities of thermal energy are also consumed. This article presents the results of practical research on improving the operation of internal combustion engines of drilling equipment and heat recovery systems of mobile diesel power plants, as well as increasing the efficiency of diesel power plants by improving their design and optimizing operating parameters.

Analysis of Hua Power Plant Beckles Stress Simulation Analysis

The thermal pipeline is important to play an important role in the operation of thermal power plant equipment, and the safe and stable operation of the body and accessories is very important. The elbow, as an indispensable part of the thermal pipeline, directly affects the safety of the unit. On the basis of the GB/T 16507-2013 “Water Pipe Boiler” standard, this article uses the simulation simulation software to analyze the stress of 90 ° elbow under different bending radius. Distribution status. The calculation results show that: under the same wall thickness, the maximum stress is concentrated in the inner arc. As the curved radius R increases, the maximum stress of the inner arc gradually decreases. At the same time Instead, it gradually increased. Under different wall thickness, the maximum stress occurs at the outer arc.

The Exergy and Energy Analysis of Change Phase Steam in Patuha Geothermal Well Production

A Geothermal Power Plant Company in West Java Indonesia have capacity around 55MW. It company have increased the well production quality to keep up the Indonesia's energy demands. The power plant has been operated around ten years, it has ten geothermal production wells and two injection wells. The either of it wells has an abnormality. It wells has water dominated condition so, the separator equipment is required to separate the steam from water and vapor. Previous study indicated that subsurface water entering the broken reservoir pipe. That leaks in reservoir pipe was repaired in 2020. The impact after the pipe have been repaired it made the fluid characteristic of reservoir be vapor dominated. After that a separator as a steam separator is no longer required. The study compares the value energy and exergy power of the power plant. The calculations are performed from the well reservoir and all power plant equipment. According to the results of the energy study, the plant's energy efficiency after the transformation increased by 0.03%, from 19.48% to 19.52%. The exergy value of the brine in either wells (separated steam cycle) is also known to be 2.512,52 kW, beyond which the value will become zero.

Ланцюги постачання в атомній промисловості світу та участь у ньому українських підприємств

The article discusses the supply chain of power equipment (in particular, nuclear power plant equipment), which will allow Ukraine to rebuild its economy more efficiently and integrate into the global market for the production of equipment that will help fulfill the commitments to decarbonize the world's economies. The author analyzes the structure of the supply chain in the global nuclear industry and considers the challenges faced by the industry in connection with the introduction of the latest small modular reactor (SMR) technologies and the climate commitments made by countries in accordance with the goals of sustainable development. The expediency of integrating Ukrainian nuclear industry enterprises into the global supply chain is substantiated and the priority steps for this integration are identified.