Power Plant Components Research Articles

Renewable energy trading: Assessment by blockchain

Renewable energy trading could be considered the next step in power trading's development. It is probable that individuals currently involved in power trading will need to upgrade their data collection, processing, and reporting systems. This article provides a comprehensive evaluation of renewable energy trading utilizing Blockchain technology. Initially, the paper examines country-specific renewable energy trading with a focus on India, China, the US, France, and Germany's renewable energy policies. Moreover, the paper presents potential renewable energy trading markets such as peer-to-peer, over the grid, and partially or fully independent microgrid's. This paper shows the appraisal of bond, commodity, derivative, and algorithm-based renewable energy trading using different Blockchain methods, including Ethereum and R3 Corda. It is find out during the renewable energy trading, proposers of bid, also include capital cost of the renewable energy power plant, salvage value after useful life of different component of renewable energy power plant. It is also find out proper trading is to be done with offering subsidies of up to 70 % of the capital cost, and with a 30 % viability gap finance (VGF) at this cost.

Creep strain prediction in power plant material via ANN modelling of nonlinear ultrasonic test results

ABSTRACT Reliable and accurate prediction of the creep life of power plant components is crucial for both economic and safety reasons. Existing prediction models, based on creep test data, can be complex and time-consuming. Nonlinear ultrasonic (NLU) is a widely-accepted non-destructive testing (NDT) technique for evaluating damage progression in crept specimens. The information from NLU measurements alone is insufficient to forecast the life of any component. In real-time applications, intelligent NDT protocols are needed to enable fast and accurate life prediction of such components. A methodology for creep life prediction using artificial neural networks (ANN) has been introduced based on NLU test results of crept P92 steel specimens. The technique involved creep tests of P92 specimens exposed to a temperature of 625⁰C with applied stress ranging from 120MPa to 160MPa, NLU measurements at each step load, and prediction of creep life of the material with a ANN trained with creep strain and NLU test data. The technique involves prediction from previously generated historical data, thus saving both cost and time of conducting continuous experiments. This approach for ANN modeling of NLU data can be considered a reliable, time-saving, and effective technique for assessing creep damage progression in power plant components.

UTILIZING DETONATION SPRAYING IN THE PROCESS OF FORTIFYING COMPONENTS WITHIN POWER PLANT TECHNOLOGY

The article addresses challenges related to enhancing the performance characteristics of power plant components. Research conducted by different authors demonstrates that when aiming to enhance the operational qualities of these parts, detonation spraying yields superior outcomes owing to its low porosity, high strength, and strong adhesion of the coatings produced. Also benefits of employing Ni-Cr-Al-based coatings as high oxidation resistant coating. The study involves the acquisition of Ni-Cr-Al-based gradient structured coatings using detonation spraying techniques. Investigated their phase composition and microstructures. By modifying the technological parameters during spraying, we achieved control over the properties of the resulting gradient coatings. Analysis of the elemental composition via the EDS method revealed that the Ni–Cr–Al gradient coatings possess a structured gradient, wherein the aluminum concentration progressively rises from the substrate towards the surface of the coating. The Ni–Cr–Al gradient coating thereby obtained the presence of phases NiCr with a surface of NiAl that has a high hardness and wear resistance.

Validated assessment of power plant components with flaws and defects operating under long-term creep and isothermal creep-fatigue loading

An extensive database of frequently used heat-resistant steels 1 %Cr, 9–10 %Cr and 12 %Cr steels at application-typical temperatures was evaluated using the Nikbin-Smith-Webster model. Influencing factors, such as the initial plasticization and the specimen thickness, were investigated in the evaluation of the fracture mechanics material characteristic values. A thickness influencing factor fB for crack initiation is proposed, which improves the crack initiation estimation using the NSW model and reduces its over-conservatism notably. It could be shown that the crack initiation and especially the crack growth under creep loading can be described with sufficient accuracy by the modification of the NSW model. The limitation in the application of the C*-parameter could also be shown and explained by the Two-Criteria-Diagram (2CD). It should be applied to crack geometries with predominant crack tip damage. The 2CD is shown as preferred method for a more precise, material-related understanding and assessment of the crack initiation process.Based on the recalculation of fracture mechanics tests on CT und DENT specimens, the analytical approaches for the description of crack initiation and growth under creep and isothermal creep-fatigue loading could be validated in the long-term range by comparison with the experimental results up to 100,000 h.Finally, the transferability of these approaches from CT und DENT specimens to large components was investigated by calculating cracked components under practical creep and isothermal creep fatigue loading using these methods. It has been shown that the load level and the duration of holding time are decisive for the crack initiation and the crack growth under isothermal creep-fatigue loading. In the case of high stress and shorter holding times, the damage is predominantly influenced by fatigue. With lower stress and longer holding times, creep plays a more important role.

Temperature homogenization control of parabolic trough solar collector field based on hydraulic calculation and extended Kalman filter

Parabolic Trough Collector fields serve as the heat-absorbing components in large-scale commercial solar trough power plants. However, they frequently encounter challenges related to uneven spatial distribution of solar irradiation and heat transfer fluid flow. These disparities often lead to temperature inhomogeneity across the field, thereby jeopardizing both the safety and economic efficiency of the collector field. To address these issues, this study first introduces a proportional-integral and feedforward based flow control strategy designed to stabilize the fluid outlet temperature in the collector field. Subsequently, a flow allocation scheme aimed at achieving temperature uniformity across individual collector loops is presented. This scheme relies on the effective irradiation estimates for each collector loop, calculated using the extended Kalman filter algorithm and a suggested hydraulic model. Simulation results demonstrate that these control strategies not only stabilize the outlet temperature of the collector field at the desired set value but also significantly diminish temperature variances among individual collector loops, with reduced computational overhead. The maximum temperature difference between loops can be reduced from 126.3 °C to 12.7 °C under uneven radiation intensity, ranging from 563 W/m2 to 885 W/m2, by the proposed temperature homogenization control strategy.

The analysis of operation and failures of a power plant on high-speed vessels with semi-submersible propellers

Over the past century, shipbuilding has been closely linked to solving the most acute problem of increasing the speed of ships. Builders of high-speed vessels habitually justify this struggle for speed in connection with the requirements of the modern market. In Russia, as well as all over the world, there is a need for modern, high-speed, maneuverable and economical vessels. To meet this need, Almaz Central Design Bureau has developed, the Rybinsk Vimpel Plant has launched a high-speed vessel with semi-submersible propellers of project 12150 "Mongoose". Currently, about 75 ships have been launched [1]. This article analyzes the work of foreign and domestic engines accumulated during the operation of high-speed engines MTU 10V2000M93 (manufactured in Germany), ZVEZDA M470MK-M3 (manufactured in Russia) installed on high-speed vessels of project 12150. In particular, information on the most characteristic failures of the components of the main power plants and the propulsion system as a whole, as well as on the possible causes of the occurrence and development of typical engine failures installed on these high-speed vessels, which allow us to assess the advantages and disadvantages of the power plant used.

Real-time stress field reconstruction method using online monitoring parameters for thick-walled power plant components based on gappy proper orthogonal decomposition

The three-dimensional stress distribution information of in-service components is of great significance for the intelligent operation and maintenance of power plants. A real-time stress field reconstruction method based on the gappy proper orthogonal decomposition (POD) and prediction function is proposed for condition monitoring of high-temperature pressured thick-walled components. Based on the “snapshots” method, the standard POD orthogonal basis is extracted from the high-fidelity data obtained from finite element analysis under various hot start load conditions to capture the main features of the stress fields. The complete stress field is reconstructed by the linear combination of the standard POD basis, and the modal coefficients are calculated using the discrete node stresses through the gappy POD procedure. Since only the online monitoring parameters of steam are available in practical operations, the prediction function is used to establish the mapping relationship between the monitoring parameters and node stress. The discrete nodes are determined by the trial-and-error method. The small global relative errors between the reconstructed stress fields and numerical solutions indicate the high accuracy of the proposed method. The spatial error of the entire stress field and the temporal error of the maximum stress were also evaluated. The computation time of the reconstruction process is significantly shorter than the sampling time step. The performance of gappy POD on different numbers of snapshots and modes was also presented.

Fault diagnosis of nuclear power plant sliding bearing-rotor systems using deep convolutional generative adversarial networks

Sliding bearings are crucial rotating mechanical components in nuclear power plants, and their failures can result in severe economic losses and human casualties. Deep learning provides a new approach to bearing fault diagnosis, but there is currently a lack of a universal fault diagnosis model for studying bearing-rotor systems under various operating conditions, speeds and faults. Research on bearing-rotor systems supported by sliding bearings is limited, leading to insufficient fault data. To address these issues, this paper proposes a fault diagnosis model framework for bearing-rotor systems based on a deep convolutional generative adversarial network (TF-DLGAN). This model not only exhibits outstanding fault diagnosis performance but also addresses the issue of insufficient fault data. An experimental platform is constructed to conduct fault experiments under various operating conditions, speeds and faults, establishing a dataset for sliding bearing-rotor system faults. Finally, the model's effectiveness is validated using this dataset.

SOLAR POWER PLANT PLANNING FOR HOUSEHOLD SCALE BY THE AID PVSYST PROGRAM

Geographically, Indonesia is located on the equator, so it is very rich in solar energy sources with an average solar radiation intensity of around 4.8 kWh/m2 per day throughout Indonesia. The main component contained in solar power plants is solar cells which function to convert sunlight into electrical energy This research discusses the Planning of Solar Power Plants for Household Scale Assisted by the PVsyst Program. The purpose of this research is to determine how many solar modules, batteries, solar charger controllers, and inverters are needed for planning solar power plants in households with 900 VA and 1300 VA power. Based on manual calculations and simulations of the PVsyst program, 10 Luxor Ecoline Half Cell 280 Wp polycrystalline modules, 12 Narada EosG 2000 Ah batteries, 1 Victron Energy Mppt 250/100 solar charge controller, and 1 Victron Multiplus Compact 24/1200/25 inverter. The capacity of the solar power plant components for 900 VA and 1300 VA household loads is approximately the same, this is because the average daily energy usage is only slightly different. In 900 VA households, the number of occupants of 6 people uses 7088 Wh/day of energy, while in 1300 VA households with 4 occupants uses 7274.5 Wh/day of energy.

Creep Resistance and Structure of 10% Cr–3% Сo–2% W–0.29% Cu–0.17% Re Steel with Low Nitrogen and High Boron Contents for Unit Components of Coal Power Plants

Creep Resistance and Structure of 10% Cr–3% Сo–2% W–0.29% Cu–0.17% Re Steel with Low Nitrogen and High Boron Contents for Unit Components of Coal Power Plants

Evaluation of Worker Radiation Exposure during the Kori Unit 1 Steam Generator Dismantling Process

Kori Unit 1 was permanently shut down on June 18, 2017. Since then, Korea is actively preparing for the decommissioning of the nuclear power plant. Because decommissioning work is performed in a radioactive environment, worker radiation exposure is a significant consideration. In this study, worker radiation exposure is evaluated during the steam generator, one of the heavy components of nuclear power plant, dismantling process. A radiation evaluation for the dismantling process is performed using the code RESRAD-BUILD. A steam generator dismantling scenario and optimal cutting method are designed to evaluate worker radiation exposure, considering pipe dimensions, cutting tool speed, and experience in steam generator replacement. The evaluation results are derived for each work type and year. As a result of the evaluation, worker radiation exposure is 7.5 man-mSv at the year of planned decommissioning.

Detection of abnormal operation in geothermal binary plant feed pumps using time-series analytics

In this study, we investigate potential pump cavitation events in circulating feed pumps deployed in a geothermal binary power plant using feature-based time series analytics and machine learning. The feed pumps have been in operation for over a decade but have been experiencing episodes wherein the pumps were drawing in lower power even while pump speeds were maintained at the same levels.A workflow combining time-series analytics and first-principle thermodynamics was applied to characterise potential drivers of the abnormal events in the feed pumps. An approach based on systematic time-series feature engineering and semi-supervised machine learning was used to fully annotate the input data and identify twenty (20) undocumented occurrences of the target event. Time-series features extracted from the fully labelled dataset were then used to train forecasting models to identify potential drivers of the target events. Forecasting models trained using pump data outperformed those trained on times-series data from other power plant components (Matthew’s correlation coefficient score of 0.490 vs 0.255). This result indicates that the abnormal events are primarily driven by operating conditions local to the feed pump system. This finding was confirmed by Bayesian A/B testing, showing that the target events were more likely to occur by 22% when four (4) feed pumps were running compared to when only three (3) pumps were in operation. Furthermore, thermodynamic analysis of the state of the working fluid across the feed pumps shows irregularities at the pump inlet, where indications of partial vaporisation of the working fluid have been identified.

Development of a Diffusion Bonding Route for Joining Oxide-Dispersion-Strengthened (ODS) Steels for Nuclear Applications

Oxide-dispersion-strengthened (ODS) steels are candidate materials for components in current and future nuclear power plants. One of the issues with using ODS steels is the difficulty of joining them without loss of mechanical performance. In this study, austenitic ODS 316L stainless steel was diffusion-bonded to Inconel 718 superalloy. Having optimized the bonding conditions, a number of samples were made at 1200 °C with a bonding time of 1 hour and pressure of 10 MPa. Preliminary mechanical and microstructural analyses indicated the formation of a sound joint interface, despite slight grain growth in the ODS 316L. A post-bonding thermo-mechanical treatment (TMT) was conducted to refine and restore the microstructure of the ODS 316L. Comparative TEM investigations of the parent ODS alloy and the bonded samples (with and without TMT) along with statistical analyses showed that the Y–Ti–O oxide size distribution remains unaffected by the bonding and complementary TMT cycles, indicating stability of such particles even at very high temperatures and suitability of the devised route for joining the ODS 316L steel.

ПЕРЕВАГИ ТА НЕДОЛІКИ АВТОНОМНИХ СОНЯЧНИХ ЕЛЕКТРОСТАНЦІЙ

The article examines the state of research and practice of using autonomous solar power plants, the advantages and disadvantages of their use in everyday life. The main concepts of solar energy, autonomy and components of solar power plants are considered. Current normative documents regarding the researched issue are considered. Solar energy is obtained from solar radiation and can be transformed into electricity or heat. It is freely available, and thanks to advances in technology, we can now use even more of the solar energy that is constantly available to us. Solar energy has the least negative impact on the environment compared to any other energy source. It does not emit greenhouse gases and does not pollute water. Its maintenance also requires very little water, unlike, for example, nuclear power plants, which require 20 times more water. The production of solar energy does not create any noise, which is a big advantage, since many solar installations, such as residential solar panels, are located in urban areas. Solar power plants are quite innovative equipment. Solar energy is one of the most dynamically developing branches of alternative (renewable) energy. Solar energy is developing at an increasing pace and has already turned into a powerful industry in the world's largest economies. In Ukraine, the growth rate of solar energy accelerated this year. Solar energy for residential buildings is a hot topic today.

Online imaging system for component integrity test

A large number of tests have been performed on piping components of Indian Nuclear Power Plants, to study their fracture behavior and generate the fracture properties, and to validate the failure models. The materials of these piping components are carbon steel and stainless-steel welds, and tests were conducted under monotonic/cyclic loading conditions. During these component tests the crack growth data measurements in sync with the applied load and load line displacement (LLD) were required to facilitate post- test calculation of fracture resistance J-R curve. Unlike in small specimens (like CT, TPB, etc.), the compliance function for large components like pipes and elbows are not available. Further, it is known that in these materials the crack growth happens in out- of-plane and, the angle at which it grows cannot be anticipated in advance. This phenomenon imposes further limitation on usage of conventional methods like compliance based / potential drop-based method used for crack growth measurement. Therefore, a new Imaging based technique was developed in-house in 2018 and used to measure crack growth during these tests during 2020-21. In this technique the synchronous images of both the crack tips and related image of computer screen showing values of applied load, LLD, etc. are acquired using single click button. The software required for synchronous acquisition of images from various cameras during fracture experiments was developed. Each image set contains images of both crack tips, and Load and LLD image. Subsequently, the crack tip images were manually analyzed to obtain the magnitude of crack growth with applied loading. This paper narrates the developed imaging system setup followed by a discussion on the software for image acquisition.

Reference Implementation of the PID Controller

The PID controller is the by far most frequently employed type of controller. As you read, billions of digitally implemented PID controllers are running, shaping the dynamic behavior of anything from the fan speed in your laptop to safety-critical components in nuclear power plants. Given the abundance of commissioned PID controllers, it is surprisingly hard to find a single source that provides a well-documented, and motivated reference implementation of the PID controller in text-based code. This work provides one. We use the incremental (velocity) form, motivated by its intrinsic integrator anti-windup and bumpless transfer behavior. In addition, we discuss our implementation in terms of measurement filtering, setpoint handling, and runtime environment, among other implementation aspects. Our reference implementation is a living “document”, and a link to a GitHub repository hosting the latest version is provided.

Crack growth behaviour of P91 steel under trapezoidal loading at high temperature

The increased incentives to utilize renewable energy sources so as to supplement the energy requirements of the present civilization pose a challenge to the power plants running on fossil fuels, as they are required to operate in a ‘flexible’ manner instead of operating at a constant load as intended during their design and inception. This flexible mode of operation at elevated temperature causes a combined creep and fatigue type of loads to be applied on the components. This allows for a comprehensive and effective understanding of synergistic creep-fatigue crack growth behaviour to assess long term failure of components and accessories in plant. The use of P91 steel has been widely prevalent in power plant components owing to its high creep resistance, superior mechanical properties and excellent thermal conductivity, cost-effectiveness, and minimal coefficient of thermal expansion when compared to austenitic steels and Ni-based alloys. The American Society for Testing and Materials (ASTM) has proposed a standard for experimentally evaluating creep-fatigue crack growth, E 2760-19, wherein compact specimens, C(T) are tested under load-controlled conditions. The creep-fatigue crack growth regime and mode of fracture undergone by P91 steel at 600 °C were studied using C(T) specimens at two different force ratio 0.1 and 0.5 and with two different hold time 10 and 600 sec. The Creep fatigue crack growth behaviour has been characterized using stress intensity factor range parameter ∆K and (Ct)avg parameter to study the effect of hold time and force ratio.

GK-SPSA-Based Model-Free Method for Performance Optimization of Steam Generator Level Control Systems

The Steam Generator (SG) is a crucial component of a Nuclear Power Plant (NPP), generating steam to transfer heat from the primary loop to the secondary loop. The control performance of the Steam Generator Level Control System (SGLCS) plays a crucial role in the normal operation of the SG. To improve the system’s performance, the parameters of the control system should be optimized. However, the steam generator and its corresponding control system are highly complex, exhibiting nonlinearity and time-varying properties. Conventional parameter-setting methods mainly rely on engineers’ experience, and are laborious and time-intensive. To tackle the aforementioned challenges, a Model-Free Optimization (MFO) method based on Knowledge-informed Historical Gradient-based Simultaneous Perturbation Stochastic Approximation (GK-SPSA) is applied to the performance optimization of the steam generator level control system. The GK-SPSA algorithm is a variant of the traditional SPSA algorithm. The fundamental idea of this revised algorithm is to maximize the utilization of historical gradient information generated during the optimization process of the SPSA algorithm, with the aim of enhancing overall algorithm performance in a model-free optimization context. Based on the effective utilization of historical gradient information, the GK-SPSA algorithm exhibits two improvements over the SPSA algorithm. The first improvement is related to the recognition of the online optimization progress, utilizing the state of the optimization progress to dynamically adjust the optimization step size. The second improvement is related to gradient estimation compensation, employing compensation rules to enhance the accuracy of gradient estimation, thus improving the optimization efficiency. Through simulation experiments, it can be observed that there is not much difference in the final iteration values among the GK-SPSA, IK-SPSA, and SPSA methods. However, the iteration count of GK-SPSA is reduced by about 20% compared to SPSA and by 11.11% compared to Knowledge-informed SPSA (IK-SPSA). The results indicate that this method can significantly improve the efficiency of parameter tuning for the liquid level control system of a steam generator.

Remarkable Potential of Cold Spray in Overlay Restoration for Power Plants: Key Challenges, Recent Developments, and Future Prospects

Cold spray has become a prominent deposition technology for coating, repair, and restoration in many industries, such as the aerospace, automotive, and power generation industries. It also has the potential to be used as an alternative overlay restoration for power plant components as it has minimal thermal distortion phase changes, as compared to conventional welding and thermal spray. This article aims to bridge the gap in the scientific literature by presenting a comprehensive review of cold spray in the context of power plant components. Firstly, this review examines the challenges of cold spray and subsequently elucidates effective mitigation strategies. Secondly, the review analyses the recent development of cold spray in the field of coating application. Moving forward, it investigates the integration of cold spray technology in repair applications, focusing on practical implementation and effectiveness. Finally, the review presents the overall impact of cold spray, its current outlook, and discusses future prospects. As such, the review will provide the community with a broad understanding of cold spray applications in the power plant sector.

Non-equibiaxial residual stress evaluation methodology using simulated indentation behavior and machine learning

Measuring the residual stress in the components in nuclear power plants is crucial to their safety evaluation. The instrumented indentation technique is a minimally invasive approach that can be conveniently used to determine the residual stress in structural materials in service. Because the indentation behavior of a structure with residual stresses is closely related to the elastic-plastic behavior of the indented material, an accurate understanding of the elastic-plastic behavior of the material is essential for evaluation of the residual stresses in the structures. However, due to the analytical problems associated with solving the elastic-plastic behavior, empirical equations with limited applicability have been used. In the present study, the impact of the non-equibiaxial residual stress state on indentation behavior was investigated using finite element analysis. In addition, a new nonequibiaxial residual-stress prediction methodology is proposed using a convolutional neural network, and the performance was validated. A more accurate residual-stress measurement will be possible by applying the proposed residual-stress prediction methodology in the future.