Power Plant Equipment Research Articles

ANALYSIS OF THE MAIN APPROACHES TO THE ASSESSMENT OF THE CONDITION OF TPP AND NPP EQUIPMENT

The materials of the article analyze the current state of the energy industry in Ukraine and the countries of the world and analyze the ways to increase the efficiency of thermal power plants and nuclear power plants. The elements of the power unit can be affected by aging processes that occur over time or as a result of long-term use. The negative impact of aging can lead to the degradation of the element, namely to the deterioration of its reliability and, as a result, the safety of the power unit as a whole. The development and implementation of measures to mitigate aging processes and to ensure reliable operation of elements during the reassigned resource period is a mandatory type of activity for managing the aging of thermomechanical equipment and pipelines.Monitoring of the technical condition of the elements is performed by monitoring the established parameters and characteristics that determine the technical condition of the elements, during their operation, during tests, measurements, operational control of metal, repairs and maintenance of the elements. Monitoring should be carried out systematically throughout the entire life of the power unit. In turn, technical diagnostics monitors the current state of all elements, detects abnormal conditions, determines the causes of their appearance, which allows you to assess the situation and take measures to eliminate them. The purpose of the article is to analyze the main approaches to assessing the state of energy equipment of thermal and nuclear power plants.

CARBON FOOTPRINT OF ELECTRICITY PRODUCTION

A methodology for calculating the carbon footprint of electricity production has been developed, which meets the requirements of the ISO 14067 standard and the methods of inventorying greenhouse gas emissions of the Intergovernmental Panel on Climate Change. Calculations of the carbon footprint of electricity production using hard coal and natural gas, as well as its components, were performed for all stages of electricity production: during the construction of power plants, fuel extraction and fuel transportation, production and transportation of electricity, and waste management of its production. A comparison of the calculation results with literature data showed a significant excess of the carbon footprint of electricity production, which is produced using hard coal and natural gas at power stations in Ukraine. The reasons for exceeding the carbon footprint of electricity production in Ukraine relative to values in other countries are explained. It was determined that the reasons for such an excess are not only due to different levels of technical condition of power plant equipment, but also depend on calculation methods, in particular, the use of different limits of the life cycle of electricity production. Also (in the case of using natural gas) using different methods of destribution of fuel costs for the production of heat and electricity in the case of combined production of heat and electricity. Expected that the results of the work will be used in the calculations of the products carbon footprint for which uses electricity. Bibl. 18, Tab. 5.

Seismic Response Effect on Base-Isolated Rigid Structures by Mass Eccentricity in Nuclear Plants

The purpose of this paper is to analyze the seismic response effect caused by the mass eccentricity of individual equipment when conducting base isolation for the improvement of the seismic performance of a nuclear power plant. Recent research has interpreted and confirmed through analysis and testing that base isolation for safety-related equipment in nuclear power plants is an efficient alternative to designing for excessive seismic loads. Depending on the equipment, unavoidable mass eccentricity can occur, which necessitates verification of the response impact caused by eccentricity. In this paper, we analyze the seismic response impact of equipment with mass eccentricity using small base isolators. To do so, sensitivity analysis of the seismic response due to mass eccentricity is conducted for a base-isolated concentrated mass model. Furthermore, three efficient mass eccentricity models suitable for testing are designed and manufactured. Simulation analyses using the finite element method (FEM) models are performed, followed by three-axis shake table tests to validate the seismic response impact of mass eccentricity. In conclusion, it is confirmed that applying small base isolators to equipment with mass eccentricity can affect seismic response impact to some extent when compared for a beyond-design-basis earthquake (BDBE).

THE DEVELOPMENT OF PICO HYDRO POWER PLANT BY UTILIZING IRRIGATION FLOW IN KASAMBANG VILLAGE OF MAMUJU REGENCY

Piko Hydro Power Plant (PLTPH) is one of the power plants that uses water as an energy source. Piko hydro is included in the category of hydropower with small power because there is no need to use too large a water discharge to produce power. The tool developed in this study is a Piko Hydro Power Plant by Utilizing Irrigation Flow. The purpose of the research is to determine the results of the development of Piko Hydro Power Plant equipment, the electrical energy produced, and the response of the community. The research method used is quantitative descriptive with the type of Research and Development (R & D) research and prototype development model consisting of 4 steps, namely needs analysis, building prototypes, installing, and evaluating. The research data obtained by making observations, questionnaires/questionnaires, and documentation. The results showed that the pico hydro power plant worked well, indicated by the excellent product validation value. The waterwheel at the plant has a maximum power of 308 watts. In the development with the application of the MPPT type charger control regulator, results were obtained able to stabilize the electrical energy produced and increase the power capability of the power plant with the help of backup battery supply. For the results of the responses of the people of Kasambang Village, Mamuju Regency as many as 15 respondents, very decent results were obtained.

Structural and Economic Approach to the Selection of Peak Regulating Capacities at Thermal Power Plants

The output of power unit No 2 of the Belarusian NPP to the level of neutron power development of 100 % of the nominal level has changed the structure of generation of the Unified Energy System (UES) of Belarus. At the current loads of the inter-heating period of 2023, the share of a nuclear power plant with two power units operating at full capacity in the daily generation structure of the Republic is about 50 %. In order to balance the UES of Belarus during the operation of two power units of a nuclear power plant at night, the application of adjustment regulatory measures that exceed the available capabilities is required. The almost complete use of the adjusting range of the CHP will forcibly cause, on a larger scale, to the shutdown of the blocks during the load failures at night, followed by the start-up from the non-cooled and hot statuses. These operating modes of generating equipment are inevitable in the current conditions of the electricity market, which has led to the emergence of most complex tasks to assess the economic and technical efficiency of involving or another equipment of power plants in such modes. The paper proposes an approach to solving the problem of achieving an effective combination of reliability and efficiency of energy systems on the example of gas turbines and CCGT power units. A generalized desirability function has been obtained, which includes a number of parameters for choosing a rational relationship and mutual influence between the reliability and efficiency of electricity production with the participation of thermal power plant equipment in regulating the daily load schedule. The proposed mathematical model is an effective means of analyzing the suitability of equipment for use in the required operating modes.

К вопросу использования контрольных электродов для технического диагностирования протекторов морских судов

The world statistics of fleet accidents indicate that the most dangerous type of damage to engineering structures are fragile destructions that occur suddenly and spread at high speed. The causes of brittle fractures are defects such as corrosion-fatigue cracks, which often occur due to active corrosion processes. Seawater contains a large number of microorganisms that contribute to the acceleration of corrosion and fouling of metal structures in contact with water. The main method of corrosion protection of systems and mechanisms of marine fishing vessels is tread protection. To increase the effectiveness of tread protection, it is necessary to improve the methods of technical diagnostics of treads in order to use new methods at ship repair plants and marine vessels. It is proposed to use control electrodes made of stainless steel for technical diagnostics of marine vessel protectors. Laboratory tests of a stainless steel electrode and a standard silver chloride reference electrode were performed. The experiment took place at the installation for technical diagnostics of marine protectors, which was specially developed at the Department of “Power Plants and Electrical Equipment of Ships” of the Kamchatka State Technical University. Control measurements of the potential of the working protector were performed for five days, while 50 single control measurements of the working potential of the protector were performed daily using each electrode. The accuracy of the measurement results was evaluated using a mathematical and statistical method. The results of diagnosing the potential of the tread, obtained using an electrode made of stainless steel, comply with regulatory requirements. The proposed type of electrode can be used by ship crews for technical diagnostics of marine vessel protectors.

ANALISA PERAWATAN INTAKE PUMP DENGAN MENGGUNAKAN METODE RISK BASED MAINTENANCE (RBM)

Intake Pump is one of the important equipment in the steam power plant of 3x10 MW electrical generator which functions to supply raw water to production of demin water, domestic water and service water. In the process of producing water through the intake pump there are several components of the intake pump that often experience damage, this can be a loss for the company, therefore requiring additional processing. In this study, the Risk Based Maintenance (RBM) method was carried out to achieve optimal maintenance by knowing the impact and risk of failure according to important intake pump components, namely impeller, bearing and shaft. Based on the analysis results of the RBM calculation, the consequences of risks accepted is low to 0.05% by the company that achieved to 221,498,196.507 Indonesian rupiah it’s to 0.13% of production capacity per year. This value exceeds the acceptance risk tolerance of 0.13% which has become a company provision. Therefore, it is necessary to plan the proposed maintenance period from the existing policy, which is carried out 48 times a year for each critical component such to reducing the number of consequences and risks to 198,002,597 Indonesian Rupiah or equal to 0.01%.

Development of software for the management of the maintenance of equipment of thermal power plants

The relevance of the use of thermal power plants for the generation of thermal and electric energy on the territory of the Russian Federation is revealed, taking into account its geographical and climatic features. The substantiation of the importance of the process of maintenance and repair in relation to boiler units, which are operated at thermal power plants, is given. Difficulties accompanying the practical implementation of this process are identified. The influence of the identified difficulties on the existing shortcomings in the process of maintenance and repair of boiler equipment and the technological pipelines connecting them and pipelines of steam and hot water is shown. The goal of the study is set, which is aimed at eliminating the identified objective difficulties and the tasks are formulated, the solution of which will contribute to the achievement of the goal. The necessity of developing specialized software for managing the process of maintenance and repair of equipment and pipelines of boiler units of combined heat and power plants is substantiated. The methodology of the work is based on the development of digital models of pipelines and boiler equipment, as well as algorithms aimed at processing the parameters of digital models. The software implementation of the developed models and algorithms is made by means of object-oriented programming in the form of a client-server application for the Windows operating system. The description of the results of software development aimed at solving the set tasks is given. Examples of some dialog boxes accompanying the functioning of the developed software are given, as well as examples of created digital models of boiler equipment and their individual elements. The practical application of the research results contributes to an increase in the degree of digitalization of industrial production in general and energy production in particular. The results obtained in the framework of this work, in the form of software, can be used to accompany the process of maintenance and repair of boiler equipment of combined heat and power plants. With appropriate adaptation, the results obtained can also be applied to boiler equipment, pipelines and apparatus that are used in the chemical, petrochemical and oil refining industries.

Spring-like Triboelectric Nanogenerator for Monitoring Body Vibration State of the Ship Power Equipment

In the navigation process, monitoring the running state of ship power plant equipment is crucial. In bad weather, when the critical equipment is abnormal, it is especially necessary to find out the root cause of the failure as soon as possible. In this case, it is required to use rapid detection equipment to detect and judge the key parameters. This paper proposes a vibration sensor (VS-TENG) of triboelectric nanogenerators based on spring vibration. The sensor adopts the spring structure inside and vibrates with the ship power equipment to collect the low-frequency vibration energy. This paper uses the VS-TENG sensors of two different spring parameters to study the electrical signal output under the excitation conditions of varying vibration frequencies. The results show that in the frequency range of 3–500 Hz, the efficient processing of different vibration excitation frequency signals can be realized, and the vibration frequency can be accurately identified. The error of medium-high frequency identification in VS-TENG is less than 1%. Especially at the resonant frequency, the maximum voltage output value can be achieved. On the PT500 Mini test bench, VS-TENG can reasonably identify the motor frequency and shutdown state. Therefore, VS-TENG can be applied to the condition monitoring of the vibration of the ship’s power plant and has a broad application prospect.

Monte-Carlo method for assessing and predicting the reliability of thermal power plant equipment

Monte-Carlo method for assessing and predicting the reliability of thermal power plant equipment

Study on Unsteady Flow Characteristics of Cooling Water Pump for Nuclear Power Plant Equipment under Low Flow Rate Conditions

During the operation of cooling water pumps, it is necessary to operate them under conditions of low flow rate. In order to improve the unstable performance of the cooling water pump under low flow rate conditions. Taking the cooling water pump as the research object, the internal flow and pressure pulsation characteristics of the cooling water pump under 0.4Q to 0.6Q conditions were investigated, and the influence of different operating conditions on the performance and vibration of the cooling water pump was analyzed. The ANSYS CFX 2022 software and the SST k-ω turbulence model were used to perform a three-dimensional numerical simulation of the cooling water pump. After analyzing the simulation results, the velocity and pressure cloud and streamline diagram within the semi-spiral suction casing and impeller were obtained. The internal flow state of the cooling water pump was then analyzed in detail under low flow rate conditions. At the same time, a series of monitoring points were set up within the impeller, and the pressure pulsation within the impeller was analyzed using the frequency domain diagram and the radial force polar coordinate diagram. The results show that at flow rates between 0.4Q and 0.6Q, a certain amount of vortex has been generated in the suction casing, which affects the flow state when entering the impeller. Furthermore, significant vortices have been generated in the middle and back part of the blade and mainly concentrated in the pump cover of the mid-open pump. At the same time, when in low flow rate conditions, the primary frequency of pressure pulsation is mainly the axial frequency, with three times the axial frequency and blade frequency following. The amplitude of the pressure surface (PS) of the blade is greater than that of the suction surface (SS) and increases as the flow rate decreases. The internal radial force corresponds with the result of pressure pulsation and exhibits a certain pattern. This study outlines the coolant pump’s internal flow and pressure pulsation characteristics under low-flow conditions. It proposes a solution to stabilize the cooling water pump at low flow rates and provides theoretical guidance for optimizing its design.

Research on operational characteristics of coal power centrifugal fans at off-design working conditions based on flap-angle adjustment

The coal power centrifugal fan (CF) is one of the most significant equipment in coal power plants, which usually works at off-design conditions according to the demand of electricity consumption. Consequently, the efficiency of CFs is far lower than the designed maximum efficiency under this condition, causing large amounts of potential energy wasted. A novel flap-angle adjustment (FAA) method is proposed to efficiently solve this problem in the CF system. This manuscript establishes a theoretical model of the flap-angle adjustable centrifugal fan (FAACF). The operating economy of FAACF at both design and off-design conditions is comprehensively studied. The internal flow mechanism of efficient operation is analyzed, which reveals the more stable flow state inside CF impellers at off-design conditions. By comparing with the traditional inlet guide vanes CF (IGVCF), the application of the FAA improves the energy efficiency of the CF system significantly. A wider high-efficiency range is obtained, which is superior to the IGVCF. The numerical results effectively reveal the mechanisms by which flow loss occurs in the FAACF at the outlet of blades. In particular, the energy-saving rate of the G4-73-11 type CF system based on the FAA can reach 20.4 % when the relative flow ratio decreases to 74 %, which proves the positive adjustment potential of energy efficiency and indicates great energy-saving benefits of the FAA application in the CF system.

Power plant induced-draft fan fault prediction using machine learning stacking ensemble

The improvement of fault prediction and diagnosis in industrial systems is crucial to minimize unscheduled shutdowns. However, the predictive performance of current models for thermal power plants is limited due to their reliance on single algorithm approaches. Furthermore, there is a shortage of experiments on thermal fired power plant equipment, as most research focuses on nuclear power plants. In this study, we propose a fault predictive stacking approach for a thermal power plant induced draft fan and evaluate the performance of base learners, including Support Vector Machines (SVM), K Nearest Neighbors (KNN), and Random Forests (RF). Our proposed stacking ensemble approach achieved a prediction accuracy of 99.89 % which demostrated superior prediction performance compared to the base methods.

Problems of Adapting the Operating Thermal Power Plant Equipment to the Technological Emission Indicators Stipulated by the Reference Document on Best Available Techniques 38-2022 “Large Combustion Plants”

Problems of Adapting the Operating Thermal Power Plant Equipment to the Technological Emission Indicators Stipulated by the Reference Document on Best Available Techniques 38-2022 “Large Combustion Plants”

Development and Investigation of the Advanced Oxy-Fuel Power Plants Equipment Preliminary Design

Development and Investigation of the Advanced Oxy-Fuel Power Plants Equipment Preliminary Design

Fault diagnosis of coal mills based on a dynamic model and deep belief network

As the significant ancillary equipment of coal-fired power plants, coal mills are the key to ensuring the steady operation of boilers. In this study, a fault diagnosis model was proposed on the basis of a dynamic model of a coal mill and deep belief network (DBN). First, a dynamic coal mill model that considered the joint influence of drying, ventilation and grinding forces was established. Parameters in the model were identified by designing a two-phase optimization method based on the genetic algorithm. Then, this model was used for simulating the common faults of coal mills under a variety of operating conditions and obtaining extensive data. On this basis, the DBN fault diagnosis model was established and the combination of parameters was optimized by use of an orthogonal experiment. Finally, the validity of the model was verified by using the actual operation data of the coal mill. Compared with the dynamic models built in previous studies, that constructed in this paper can significantly improve the capability to simulate and analyze the coal mill. The convergence rate of the designed two-phase optimization method was improved. The experimental results show that the proposed method of coal mill fault diagnosis based on the dynamic model and DBN has an accuracy of 95%, which proves that this method has excellent application potential.

Improvement of methods for analyzing the technical condition of electromechanical equipment of nuclear power plants

The article analyzes the problem of diagnostics of NPP electric drive valves. Failure of this type of equipment can become the initial event for design or beyond design accident. Therefore, during the period of preventive maintenance at NPPs diagnostics of up to 2000 units of valves is carried out mainly by registration and analysis of the motor current signal during opening and closing. However, the applied statistical and frequency analysis methods do not always provide the necessary quality of diagnostics. The article points out the disadvantage of the applied methods – insensitivity to the dynamics of electromechanical equipment in terms of nonlinear manifestations of defects. As a tool for analyzing these manifestations the phase-plane method is proposed and its theoretical basis is outlined. The diagnostic signal is described as a vector diagram of a harmonic series subjected to amplitude and phase modulation. The most characteristic forms of phase trajectories - cardioids, nephroids, epicycloids – are shown. The main advantages of the phase-plane method over traditional frequency methods – sensitivity, possibility to identify the type of modulation, phase shift, dynamic and chaotic manifestations – are demonstrated by examples of processing diagnostic signals of NPP equipment. An important advantage of signal representation in the form of phase portrait is the visualization of dynamic features of the signal. The result of the work is a new method that allows to extract additional information about the object state by analyzing the non-stationary component of the initial data. It is proposed to introduce the phase-plane method into the practice of processing diagnostic signals of electric drive valves and other electromechanical equipment operated at NPPs.

Two-Stage Optimization Scheduling of Virtual Power Plants Considering a User-Virtual Power Plant-Equipment Alliance Game

Distributed renewable energy, loads, and power sources can be aggregated into virtual power plants (VPPs) to participate in energy market transactions and generate additional revenue. In order to better coordinate the transaction relationships among various entities within VPPs, this paper proposes a two-stage optimization model for VPPs that considers the user-VPP-equipment alliance. Firstly, starting from the basic structure of VPP, it is proposed to divide the alliances in VPP into two alliances: demand-side user-VPP and supply-side equipment-VPP. And a VPP optimization framework considering the cooperative game of the user-VPP-equipment alliance has been established. Then, a two-stage optimization model for VPPs was established considering the cooperative game of user-VPP-equipment alliance. The day-ahead optimization model takes economic and social benefits as the dual objectives, and the intraday optimization model aims to minimize the cost of deviation penalties. Secondly, taking into account the risk levels and comprehensive marginal benefits of various entities within the VPP, a profit distribution method combining improved Shapley values and independent risk contribution theory is adopted to allocate the total revenue of the VPP. The case results show that the operating cost has been reduced by 5.75%, the environmental cost has been reduced by 4.46%, and the total profit has increased by 29.52%. The model can improve the overall efficiency of VPPs.

Fault Detection of Rotor Bars in Inverter-Fed Induction Motors Based on Current Signature Analysis Technique

Induction motors, which are one key piece of equipment for power plants, waterworks facilities, and factories, must be maintained appropriately for reliable operation. A motor current signature analysis (MCSA) technique, which monitors and detects problems in motors and diagnoses devices, has already been marketed by some companies. Recently, applications of inverter-fed motors have increased for greater energy conservation. However, a fault-detection method in inverter-fed motors has been inadequately studied despite the risk of misdetection due to inverter noise. This paper shows our results that detected a broken rotor bar in an inverter-fed motor based on a MCSA technique. An abnormal motor with a broken rotor bar and a normal motor are driven by an inverter. The current supplied to both motors is measured and the frequency spectra results are compared. In the measurements, the inverter’s drive frequency is varied from 120 to 10 Hz in 10 Hz increments. In each drive frequency, the slip is varied in a range of 0-5% by adjusting the load connected to the motor. The results of comparing the current spectra show significant reinforcement of the signal intensities in abnormal motors. Some signals are reinforced by both inverter noise and a component that originated in the broken bar. The superposition that may lead to a misdiagnosis in inverter-fed motors is avoided by identifying the normal spectrum shapes of the target equipment in advance.

Degradation analysis of horizontal steam generator tube bundles through crack growth due to two-phase flow induced vibration

A correct understanding of vibration-based degradation is crucial from the standpoint of maintenance for Steam Generators (SG) as crucial mechanical equipment in nuclear power plants. This study has established a novel approach to developing a model for investigating tube bundle degradation according to crack growth caused by two-phase Flow-Induced Vibration (FIV). An important step in the approach is to calculate the two-phase flow field parameters between the SG tube bundles in various zones using the porous media model to determine the velocity and vapor volume fraction. Afterward, to determine the vibration properties of the tube bundles, the Fluid-Solid Interaction (FSI) analysis is performed in eighteen thermal-hydraulic zones. Tube bundle degradation based on crack growth using the sixteen most probable initial cracks and within each SG thermal-hydraulic zone is performed to calculate useful lifetime. Large Eddy Simulation (LES) model, Paris law, and Wiener process model are considered to model the turbulent crossflow around the tube bundles, simulation of elliptical crack growth due to the vibration characteristics, and estimation of SG tube bundles degradation, respectively. The analysis shows that the tube deforms most noticeably in the zone with the highest velocity. As a result, cracks propagate more quickly in the tube with a higher height. In all simulations based on different initial crack sizes, it was observed that zone 16 experiences the greatest deformation and, subsequently, the fastest degradation, with a velocity and vapor volume fraction of 0.5 m/s and 0.4, respectively.