Turbine Power Plant Research Articles

The Applications of Real-Time Data Mining Technology in Fault Prediction of Power Plant Generator

This paper mainly discusses the applications of real-time data mining technology in fault prediction of power plant generator. Massive real-time historical data of thermal power plant turbine generator equipment is stored to realize comprehensive quantitative assessment of thermal power plant turbine generator’s online security status and potential failure Early Warning. It is based on the Real-time data mining analysis and modeling techniques.

Modal characteristics of turbine blade packets under lacing wire damage induced mistuning

Effect of mistuning on turbo machine blade vibration in a packeted blade–disk system has become an important area of research in the recent past, mainly due to the critical applications in aero engines and power plant turbines. It has been shown that even a small mistuning can lead to stress build up through mode localization under forced vibration. Such mistuning can come from initial geometric blade to blade variation due to manufacturing tolerances or from a crack growing in the bladed disk system during operational life stages. The literature review indicates that researchers have mainly considered blade damage as a cause of mistuning. However, lacing wire damage, although not as catastrophic as blade damage, are more frequent in occurrences and often act as a precursor to subsequent blade damage. Detection of lacing wire damage is therefore equally important. Present work has investigated nature of mistuning induced by lacing wire damage and its effect on the characteristic modal properties. A damage severity index has been introduced and effect of damage on the blade group natural frequencies is investigated. Scope of developing a damage identification methodology in packeted blade–disk system is also discussed.

The effectiveness of power-generating complexes constructed on the basis of nuclear power plants combined with additional sources of energy determined taking risk factors into account

The effectiveness of combining nuclear power plants equipped with water-cooled water-moderated power-generating reactors (VVER) with other sources of energy within unified power-generating complexes is analyzed. The use of such power-generating complexes makes it possible to achieve the necessary load pickup capability and flexibility in performing the mandatory selective primary and emergency control of load, as well as participation in passing the night minimums of electric load curves while retaining high values of the capacity utilization factor of the entire power-generating complex at higher levels of the steam-turbine part efficiency. Versions involving combined use of nuclear power plants with hydrogen toppings and gas turbine units for generating electricity are considered. In view of the fact that hydrogen is an unsafe energy carrier, the use of which introduces additional elements of risk, a procedure for evaluating these risks under different conditions of implementing the fuel-and-hydrogen cycle at nuclear power plants is proposed. Risk accounting technique with the use of statistical data is considered, including the characteristics of hydrogen and gas pipelines, and the process pipelines equipment tightness loss occurrence rate. The expected intensities of fires and explosions at nuclear power plants fitted with hydrogen toppings and gas turbine units are calculated. In estimating the damage inflicted by events (fires and explosions) occurred in nuclear power plant turbine buildings, the US statistical data were used. Conservative scenarios of fires and explosions of hydrogen-air mixtures in nuclear power plant turbine buildings are presented. Results from calculations of the introduced annual risk to the attained net annual profit ratio in commensurable versions are given. This ratio can be used in selecting projects characterized by the most technically attainable and socially acceptable safety.

Fault tree analysis of Rukhia gas turbine power plant

The working principle of gas turbine power plant systems (GTPPSs) is very complex in nature. A modelling procedure of GTPPSs on the basis of variations in the component behaviour of the compressor, combustion chamber, turbine, generator and electrical system of a gas turbine power plant is presented in this paper. A fault tree analysis (FTA) is carried out on the GTPPSs to define and enumerate specifically the causes of the system failure modes or “top events” in terms of component failures and human errors, represented by “basic events”. FT quantification also enables the probability of top events to be calculated in addition to cost components of each basic event. The findings can be useful to the designers and operating personnel of GTPPSs.

Эффективность применения парогазовых технологий на АЭС с турбинами насыщенного пара

Эффективность применения парогазовых технологий на АЭС с турбинами насыщенного пара

Off shore Wind Power Plant in the Adriatic Sea: An Opportunity for the Croatian Economy

The significant growth of renewable energy production in the past decades is present mainly due to the global depletion of fossil fuel reserves. One of interesting and well developed renewable energy technologies are wind turbines which are mainly built onshore. Due to more favorable wind characteristics at sea, off shore wind power plants are an interesting and challenging option for meeting future energy demands. In particular, less turbulent wind with higher average velocity enhances energy production and reduces structural fatigue of wind energy structures. In this study, benefits and drawbacks of off shore wind turbine units and power plants are pointed out. Based on the available climate data, sea depths and existing sea traffic routes, two possible wind power plants, i.e. one with fixed and another with floating turbines, are proposed for installation in the Croatian part of the Adriatic Sea. Benefits for the Croatian shipbuilding industry and its economy are pointed out.

Reconstruction of missing data in multidimensional time series by fuzzy similarity

The present work addresses the problem of missing data in multidimensional time series such as those collected during operational transients in industrial plants. We propose a novel method for missing data reconstruction based on three main steps: (1) computing a fuzzy similarity measure between a segment of the time series containing the missing data and segments of reference time series; (2) assigning a weight to each reference segment; (3) reconstructing the missing values as a weighted average of the reference segments. The performance of the proposed method is compared with that of an Auto Associative Kernel Regression (AAKR) method on an artificial case study and a real industrial application regarding shut-down transients of a Nuclear Power Plant (NPP) turbine.

Enhancing the Economic Competitiveness of Concentrating Solar Power Plants Through an Innovative Integrated Solar-Combined Cycle With Thermal Energy Storage

The present work deals with the thermo-economic analysis of an innovative combined power cycle consisting of a molten-salt solar tower power plant with storage supported by additional heat provided from the exhaust of a topping gas-turbine unit. A detailed dynamic model has been elaborated using an in house simulation tool that simultaneously encompasses meteorological, demand and price data. A wide range of possible designs are evaluated in order to show the trade-offs between the objectives of achieving sustainable and economically competitive designs. Results show that optimal designs of the novel concept are a promising cost-effective hybrid option that can successfully fulfill both the roles of a gas peaker plant and a baseload solar power plant in a more effective manner. Moreover, designs are also compared against conventional combined cycle gas turbine (CCGT) power plants and it is shown that, under specific peaking operating strategies (P-OSs), the innovative concept cannot only perform better from an environmental standpoint but also economically.

Design and Analysis of Cross Flow Turbine for Micro Hydro Power Application using Sewerage Water

The objective of this study endeavor is to describe the design of an environment friendly captive micro hydel power plant at the sewerage treatment plant outlet fall at Lai Nallah located in I-9 Islamabad. It will use sewerage water of CDA as discharge water to run the turbine of the micro hydel power plant to generate electricity. The important phases of the project are to carry out survey for collection of data about hydrology, quantity of flow of water, fall head, geology and design of an efficient turbine. Complete design calculations of turbine have been performed along with static and model analysis of the turbine. Key parameters to increase efficiency of cross-flow turbine are discussed.

Hot Corrosion Behaviors of Cr2alc, Cr3C2, and Al4C3 Thin Film Coatings on Ni-201

Hot corrosion, also known as deposit-induced accelerated oxidation, is an insidious challenge for hardware within high-temperature systems, such as gas turbines in combined cycle power plants and aircraft engines. This hardware, generally consisting of nickel based super-alloys, often requires protective surface coatings to satisfy the requirements of both superior mechanical properties and high-temperature corrosion resistance.Mn+1AXn (abbreviated as MAX, where M is an early transition metal, A is an IIIA- or IVA-group element, and X is C or N) phases have received increasing attention because of their unique combination of properties including excellent thermal shock resistance and damage tolerance. Among them, Cr2AlC has attracted considerable interest because of its excellent high-temperature oxidation and hot corrosion resistance. The main objective of this study is to determine the effectiveness of Cr2AlC, Cr3C2 and Al4C3 thin film coatings for the hot corrosion protection of Ni-201. Different thin film coatings were deposited via magnetron sputtering physical vapor deposition (PVD) before being exposed to air and 2 ppm SO2 at both 700°C and 900°C for up to 200 hours to simulate hot corrosion conditions.Phase compositions of each coating before and after exposure were assessed using x-ray diffraction (XRD) and their corresponding morphologies (surfaces and cross sections) analyzed with a scanning electron microscope (SEM) equipped with an energy dispersive x-ray spectroscopy (EDS) system. The coated specimens exhibited much better oxidation behavior as compared to the bare material. A continuous oxide scale formed on the coating surface during the initial oxidation stages. The oxide scale and coating itself acted as diffusion barriers blocking the further ingress of oxygen and protected the substrate alloy from oxidation. The oxidation mechanisms of the bare alloy and the coated specimens were proposed and compared based on the experimental results. The coating degradation can be attributed to the Al and Cr consumption by surface oxidation and inter-diffusion between the coating and the substrate. Results and interpretations will be presented and discussed in context of improving mechanistic understanding of hot corrosion behaviors of MAX phase materials.

A novel fault detection system taking into account uncertainties in the reconstructed signals

A typical fault detection (FD) system comprises: (1) a model that reconstructs the values of the measured signals in normal conditions, (2) a technique for the analysis of the differences (residuals) between the measured and reconstructed values, and (3) a decision strategy for defining when the monitored situation is to be detected as anomalous, i.e., reflecting a fault. Traditional techniques for this task, like threshold-based methods and the Sequential Probability Ratio Test (SPRT), show difficulties in setting their parameters and in providing information on the confidence of the FD system outcomes. In this context, the objective of the present work is to develop a novel, non-parametric, sequential decision strategy to decide whether the component is in normal or abnormal conditions that takes into account the quantified uncertainty on the reconstructions in the form of Prediction Intervals (PIs). The Auto-Associative Kernel Regression (AAKR) method is adopted to build the empirical model of signal reconstructions. The novel FD system has been tested using an artificial case study representing the monitoring of a component during typical start-up transients and it is validated using a real industrial case concerning 27 shut-down transients of a nuclear power plant (NPP) turbine. The obtained results show that the approach is able to guarantee low false and missing alarm rates and, hence, provide the decision makers with robust information for establishing whether a maintenance intervention is required or not.

Exergy Based Parametric Analysis of a Heat Recovery Steam Generator

Increasing the performance of a Heat Recovery Steam Generator (HRSG) through efficient utilization of energy associated with flue gases coming out of gas turbines in combined cycle power plants is finding a significant place in research. Amongst different approaches the second law analysis is well suited for finding out the loss of exergy at various locations, its type, and magnitude. Such information is of use in the design of new HRSG technologies and to reduce the inefficiencies in existing HRSGs. This paper presents the exergy analysis of the HRSG for calculating exergy losses, heat transfer and pressure losses for different physical components. Study indicates that various sub sections of heat recovery steam generator having different physical parameters like fin density, fin thickness, fin height, tube diameter and fin spacing show a noticeable effect on exergy loss minimization.

Fretting fatigue crack analysis of the turbine blade from nuclear power plant

The root cause of the failure of a cracked blade in the low pressure turbine of a nuclear power plant was investigated. The low clearance between the blade and the disk caused a sliding motion, which led to fretting wear during in-service operations. The crack in the blade was determined to have initiated under fretting wear and propagated with high cycle fatigue by means of analyzing the fracture surface of the failed blade. Micro oxide particles were detected from the Electron Dispersive Spectroscopy data analysis at the fatigue initiation position as typical evidence of fretting wear. The stress distribution on the blade in normal service was calculated with a non-linear elastic–plastic finite element method. The analysis results show that the crack initiation location was different with the location of the highest Mises stress. The fretting fatigue crack initiated under a combination of fretting wear and relatively high Mises stress. Designed fretting fatigue experiments were performed with the results that the fatigue life was greatly reduced by the interaction of the loading history and local fretting wear.

Coordinated optimization of the parameters of the cooled gas-turbine flow path and the parameters of gas-turbine cycles and combined-cycle power plants

In the present paper, we evaluate the effectiveness of the coordinated solution to the optimization problem for the parameters of cycles in gas turbine and combined cycle power plants and to the optimization problem for the gas-turbine flow path parameters within an integral complex problem. We report comparative data for optimizations of the combined cycle power plant at coordinated and separate optimizations, when, first, the gas turbine and, then, the steam part of a combined cycle plant is optimized. The comparative data are presented in terms of economic indicators, energy-effectiveness characteristics, and specific costs. Models that were used in the present study for calculating the flow path enable taking into account, as a factor influencing the economic and energy effectiveness of the power plant, the heat stability of alloys from which the nozzle and rotor blades of gas-turbine stages are made.

Resource recycling of superalloys and hydrometallurgical challenges

Superalloys are high melting temperature, excellent creep resistance, anti-corrosive, and oxidation resistant alloys; they are predominantly used in gas turbines of aircraft engines and power plants. Today, a series of superalloys is available according to their composition and applications. The tough nature of superalloys makes it difficult to recycle them after they are formed; this increases the demand and shortage of the energy-critical elements that are their raw materials and makes their processing one of the most demanding form of recycling today. A few processes are available, and some of these unique recycling systems are in use; however, a lack of data and/or information exists for two reasons: (i) scrap recycling is most frequently performed by superalloy manufacturers themselves (not always by the same unit) by recharging them into molten charges, and (ii) the recycler does not want to produce business for their rivals. This article presents an overview of the processes investigated to recycle superalloys, including the advantages and disadvantages of each. The available processes are not very technologically or economically feasible; therefore, further efforts are necessary to explore these processes and to make a value-added product by recycling superalloys rather than just re-melting them. Considering the continuously increasing number of alloyed elements in advanced superalloys, this paper also notes to the challenges associated with hydrometallurgical recycling of superalloys and the need for future studies on this topic.

An innovative approach in fault diagnostics of steam turbine performance using ANN and M-SVM algorithms

In this study, an artificial neural network (ANN) and multi-support vector machine (M-SVM) models are developed to predict seven kinds of faults associated with turbine of thermal power plant. Information about changes with respect to base (design / performance guaranteed) values in seven key parameters/indices namely throttle flow, throttle pressure, first stage pressure, hot reheat pressure, cross-over pressure, HP efficiency and IP efficiency enable proper interpretation of different faults such as solid particle erosion (SPE ) in HP turbine, IP turbine, deposits and peening in HP turbine, deposits and peening in IP turbine, deposits in IP turbine, rubs in IP turbine and deposits and damages in IP turbine. All the fault types are diagnosed based on observation of seven process parameters/ indices over a long time. The trends of changes - either increasing or decreasing direction – with respect to base values are fed as inputs to the networks and their output identifies the type of fault. A comparison between the classifier models is discussed with the proposed action plan to improve the smooth running of the machines

POWER SYSTEM OF THE FUTURE. THE CONCEPT OF SMART GRID. SPECIFICITY OF REALIZATION IN UKRAINE

Work is dedicated to a perspective of electrical power systems creation of the future. All modern strategic directions of generation sources development of the electrical power and power supply systems as a whole are in details considered. Special item in work is allocated to power supply systems of the Smart Grid conception with a big share of renewable energy sources, and also specificity of their realization in Ukraine. The project of educational scientific center «Smart Grid – DonNTU» constructed in Donetsk National Technical University in which the physical model of an «intellectual» power system is realized is considered. The power part of «Smart Grid – DonNTU» laboratory represents block structure in which in the blocks form such models are realized: physical model of a thermal power plant, a real solar power plant, wind turbines models, energy stores, reactive power compensators. The special bench for detailed studying of modern digital relay protection of the SiprotecTM series of Siemens® production is also realized. The physical model of the condensation turbine of a thermal power plant, and also models of wind-generating installations are executed by means of induction electrical motors with the short-circuited rotor, established on one shaft with generators of AC current. The solar power plant realized in laboratory, represents fifty five modern solar panels of the Ukrainian production with a total power of 10 kW. As model of hydrogen installation with hydrogen fuel cells in the project was accepted the educational station «Nexa® Lernsystem» with a rated power of 1,2 kW was created. This installation is equipped with necessary monitoring and optimization systems, and also built-in system of power management. At creation of laboratory installation the principle of maintenance in node constant value of reactive power due to use of dynamical reactive power compensators that will allow providing the maximum speed of the compensator is assumed as a basis and to increase its efficiency. By means of the PROFIBUS data bus all elements of physical model is integrated into the general control system of laboratory. In total this laboratory allows to model physically different normal, abnormal and emergency conditions of power supply systems of the Smart Grid conception work

Transients Analysis of a Nuclear Power Plant Component for Fault Diagnosis

We analyze signal data collected during 148 shut-down transients of a nuclear power plant (NPP) turbine for fault diagnosis. The aim is to identify groups of transients with similar characteristics, under the conjecture that faults and malfunctioning of the same type lead to a similar behavior of the measured signal transients. The fault diagnosis method is based on the combined use of an original fuzzy-based slope and similarity analysis with spectral clustering.

Geometric Modularity in the Thermal Modeling of Solar Steam Turbines

To optimize the start-up schedules of steam turbines operating in concentrating solar power plants, accurate predictions of the temperatures within the turbine are required. In previous work by the authors, thermal models of steam turbines have been developed and validated for parabolic trough solar power plant applications. Building on these results, there is an interest to increase the adaptability of the models with respect to different turbine geometries due to the growing trend of having larger steam turbines in parabolic trough and solar tower power plants. In this work, a modular geometric approach has been developed and compared against both the previous modeling approach and 96h of measured data from an operational parabolic trough power plant. Results show a large degree of agreement with respect to the measured data in spite of the different detail levels. The new model allows for simple and fast prediction of the thermal behavior of different steam turbine sizes and geometries, which is expected to be of significant importance for future concentrating solar power plants.

Thermal Testing of 255-MW Gas Turbine of a Single-Shaft Combined-Cycle Power Plant

Thermal tests of a single-shaft CCPP are conducted. A procedure for processing the test data is developed. Characteristics of turbomachinery at load N GT ≥ 0.4N r are determined. The high temperature of the exhaust gases (650°C) is provided by adjusting the inlet guide vanes.