Steam Turbine Generator Research Articles

Mathematical Modelling and Parameter Estimation of an Industrial Steam Turbine-Generator Based on Operational Data

In this paper, mathematical modeling and identification of an industrial, 200 MW steam turbine and generator are taken into consideration based on operational data. This data is acquired by the measuring devices and data acquisition systems from precisely designed tests. Due to the significance of power systems dynamic studies, steam turbine-generator as the main part of this system deserves an accurate and consistent dynamical model. After introducing the operation and the main parts of the studied steam turbine-generator, an appropriate mathematical model which best describes the behavior of the real system is proposed. In the next step, parameters of the suggested model and the generator are estimated using the nonlinear least squares (NLS) method. The accuracy of the suggested model with the estimated parameters is investigated by comparing the model response with the real data.

Small-scale steam turbine and electric generation from municipal solid waste

Small-scale steam turbine and electric generation from municipal solid waste

Small-scale steam turbine and electric generation from municipal solid waste

This is a comprehensive study of electric generation through municipal solid waste on Providencia Island, Colombia. It focuses on the benefits that waste-to-energy facilities bring to small communities and even large ones. The importance of the refuse classification and its separation in obtaining the suitable power is considered in the paper. Afterwards the data, such as pressure, mass flow rate and temperature outlet, is used to design and set the basic parameters in the steam turbine, which leads in the election of the best electric generation for this sort of application. The results of this study will show some brief quantification benefits of this way of electric generation in small and probably large populations based on electric demand covered, CO2 emissions, landfilling and money savings with the use of fewer diesels for electric generation. The study comes to the conclusion that the electric generation through municipal solid waste can cover from 7 up to 15% of the electric demand of the population, which gives valuable information on the way that we generate electricity nowadays.

国投北疆电厂汽轮发电机组安装质量管理方法探讨及实践

国投北疆电厂汽轮发电机组安装质量管理方法探讨及实践

Environmentally Friendly Replacement of Mature 200 MW Coal-Fired Power Blocks with 2 Boilers Working on One 500 MW Class Steam Turbine Generator (2on1 Unit Concept)

Abstract The paper covers problems of the owners of a fleet of long-operated conventional power plants that are going to be decommissioned soon in result of failing to achieve new admissible emissions levels or exceeding pressure elements design lifetime. Energoprojekt-Katowice SA, Siemens AG and Rafako SA presents their joint concept of the solution which is a 2on1 concept - replacing two unit by two ultra-supercritical boilers feeding one turbine. Polish market has been taken as an example.

Condition monitoring of a steam turbine generator using wavelet spectrum based control chart

Condition-based maintenance (CBM) is designed to take maintenance actions only when there is an imminent evidence of failure for a monitoring system. The parameters indicating health status of the system are continuously monitored in CBM. This article proposes a condition monitoring scheme based on energy profiles generated from wavelet spectrum analysis. The energy of time series is represented by a wavelet spectrum in scale representations of signals. After deriving wavelet spectrums using a discrete wavelet transform at pre-specified windows, we aim to monitor the system based on multivariate T2 chart for the parameters in the linear energy profiles. The monitoring scheme is applied to temperature signals measured from a steam turbine generator. The proposed T2 chart based on the energy profiles shows a potential in early detecting the abnormality of a monitoring system which is not clearly detectable in original time scales.

EXERGETIC OPTIMIZATION OF PHOSPHORIC ACID FACTORY POWER PLANT

An Energetic and Exergetic Analysis is conducted on a Steam Turbine Power Plant of an existing Phosphoric Acid Factory. The heat recovery systems used in different parts of the plant are also considered in the analysis. Mass, thermal and exergy balances are established on the main components of the factory. A numerical code is established using EES software to perform the calculations required for the thermal and exergy plant analysis. The effects of the key operating parameters such as steam pressure and temperature, mass flow rate as well as seawater temperature, on the cycle performances are investigated. The minimum Exergy Destruction Rates are obtained for the condensers and deaerators followed by the blowers and turbines. The Steam Turbine Generator STGI presents the maximum irreversibility rates of about 4.1 MW. For the explored ranges of HP steam pressure, the energy efficiencies of steam turbine generators STGI and STGII increase of about 1.37 % and 8.8 % respectively. While the exergy efficiencies increase of about 2.46 for STGI and 6.8 % for STGII. In the same way optimum HP steam flow rate values, leading to the maximum exergy efficiencies are defined.

Project delay analysis of HRSG

Completion of HRSG (Heat Recovery Steam Generator) fabrication project sometimes is not sufficient with the targeted time written on the contract. The delay on fabrication process can cause some disadvantages for fabricator, including forfeit payment, delay on HRSG construction process up until HRSG trials delay. In this paper, the author is using semi quantitative on HRSG pressure part fabrication delay with configuration plant 1 GT (Gas Turbine) + 1 HRSG + 1 STG (Steam Turbine Generator) using bow-tie analysis method. Bow-tie analysis method is a combination from FTA (Fault tree analysis) and ETA (Event tree analysis) to develop the risk matrix of HRSG. The result from FTA analysis is use as a threat for preventive measure. The result from ETA analysis is use as impact from fabrication delay.

Nonlinear Synergetic Governor Controllers for Steam Turbine Generators to Enhance Power System Stability

This paper proposes a decentralized nonlinear synergetic governor controller (NSGC) for turbine generators to enhance power system stability by using synergetic control theory and the feedback linearization technique. The precise feedback linearization model of a turbine-generator with a steam valve control is obtained, at first, by using a feedback linearization technique. Then based on this model, a manifold is defined as a linear combination of the deviation of the rotor angle, speed deviation, and speed derivative. The control law of the proposed NSGC is deduced and the stability condition of the whole closed-loop system is subsequently analyzed. According to the requirement of the primary frequency regulation, an additional proportional integral (PI) controller is designed to dynamically track the steady-state value of the rotor angle. Case studies are undertaken based on a single-machine infinite-bus system and the New England system, respectively. Simulation results show that the proposed NSGC can suppress the power oscillations and improve transient stability more effectively in comparison with the conventional proportional-integral-derivative (PID) governor controller. Moreover, the proposed NSGC is robust to the variations of the system operating conditions.

Analytical study of power generation efficiency of WtE systems operating in Tokyo special ward district

This paper attempts to present a fundamental system analysis for the performances of currently operating waste-to-energy incinerators in Tokyo special ward district. Firstly, it is stated that the gross thermal efficiency η G of any steam turbine generation system could be expressed as a product of four parameters: the boiler efficiency η b, turbine steam utilization fraction R t, heat cycle constant R h, and turbine generator chamber efficiency η tg. Secondly, reliable heat inputs to waste-to-energy systems were established by the ideal boiler efficiencies η b,ids which are based on the versatility of the standardized combustion gas properties, to avoid totally depending on the conventional low calorific value measurements of the fed-waste which occasionally include dubious results. Thirdly, the achievement of technological progress of power generation in waste-to-energy systems over the past 3 decades was reviewed. The advantage of 4 MPa class incinerators (installed after 2001) over 3 MPa class incinerators (installed before 1999) in η G by 33.1% on average was clarified. Fourthly, the difference in operational modes which affects the η G was studied to seek for the optimum operation in terms of energy recovery. In conclusion, this paper evaluated that the overall η G of the 20 incinerators in FY2015 proved to be 15.0%.

The Trapezoid Counterweight Method in Dynamic Balance of Symmetric Flexible Rotor

Steam turbine generator unit, water pump and other high speed revolution symmetric flexible rotor were regarded as research objects in this paper. According to variation characteristic of rotor shaft in rigid and flexible working mode, nine-reel high pressure water pump rotor was analyzed. The former four-order intrinsic frequency of flexible rotor was obtained by modal analysis and harmonic response analysis. The methods of reaction force response and unbalance response were been studied after first order and second order resonance region eliminating in different modes of simple harmonic exciting force. Based on above theoretical research results, trapezoid counterweight method was proposed for dynamic balance of flexible rotor. This method solved problem that rigid dynamic balance of low speed rotor was destroyed after first order and second order resonance region counter weight in dynamic balance of flexible rotor. The dynamic balancing techniques of flexible rotor could be improved the qualities of rotor and its relative products by this method, eliminating the vibration of unbalance mass of products radically.

CCS on Offshore Oil and Gas Installation - Design of Post-Combustion Capture System and Steam Cycle

Most of the released CO2 on offshore oil and gas installation originates from the gas turbines that power the installations. For certain offshore installations, CO2 capture and storage (CCS) could be an alternative to decrease the CO2 emissions. When opting for a chemical absorption CO2 capture system, a heat source for the stripper reboiler is needed. Since most offshore installations are powered by simple cycle GTs, there is typically no steam available that could be used for stripper reboiler heat. A compact steam bottoming cycle could, in addition to providing the reboiler steam, partly or fully provide power from a steam turbine generator to the equipment in the CCS system, including CO2 compressors, pumps, and flue gas booster fan. Three different steam cycle configurations were designed, modeled, and simulated. The design of the post-combustion CO2 capture system is also presented but the main focus in the paper is on the steam cycle design. In addition to the energy and mass balance results, a weight assessment of the major equipment was done with the objective to come up with a simplified weight relationship for changes in the oil and gas installation size in terms of changes in total mass flow from the gas turbines. A steam cycle with a back-pressure steam turbine was ultimately selected. The back-pressure option was able to provide all necessary steam and power (with some margin) to the CO2 capture and compression system.

Performance of natural draft hybrid cooling system of large scale steam turbine generator unit

To overcome the shortage of dry cooling technology for large scale steam turbine generator unit in summer, the potential feasibility of hybrid cooling was investigated numerically. The physical model was established for the thermo-flow performances of a hybrid cooling system, which combined the air-cooled heat exchangers and water spray facility in a natural draft cooling tower. The mathematical model included the heat and mass transfer between circulating water and cooling air, as well as the condensation of exhaust steam from turbine. The impacts of cooling modes, operating parameters and ambient conditions of the natural draft hybrid cooling system were investigated accordingly. The results showed that both dry and wet cooling sections determined the thermo-flow performances of hybrid cooling system. Due to the blocking effects of upstream air-flows with medium wind speeds, the hybrid cooling mode may have poorer performance than that of dry cooling system. The large droplet diameter and low spray water flow ratio could deteriorate the thermo-flow performances of hybrid cooling mode, which were even worse than that of dry cooling mode and dry cooling system. The operating parameters obtained and the conditions of cooling mode selection may benefit the future application of the hybrid cooling technology.

Thermal Transport Properties of New Coatings on Steels for Supercritical Steam Power Plants

In order to protect steels from oxidation and corrosion under steam- and fire-side exposures for the next generation of steam turbines, different protective coatings (slurry Al, pack Al, thermal spray CoNiCrAlY, HIPIMS CrN/NbN, sol–gel Al2O3/AlPO4) were assessed on ferritic–martensitic P92 and austenitic HR3C steels. Cyclic oxidation in air at 650 and 700 °C was subsequently conducted for the coatings to grow oxide scales. The thermal transport properties of both the as-deposited and the oxidised coatings were investigated by laser flash analysis till 900 °C to ascertain whether they exhibited any potential harmful insulation to the underlying steel substrate. The results indicated that neither the coatings nor their oxides had any impact on the thermal diffusivity in the temperature range of interest. The thermal diffusivity values were mostly dictated by those of the substrate. It is thus expected that the influence on the thermal transport properties of the coatings under steam conditions will be equivalent than in air.

SS resonance analysis of complex power system incorporating wind power

This study aims to conduct the sub-synchronous (SS) resonance analysis of a multi-machine power system incorporating doubly fed induction generator (DFIG)- or permanent magnetic synchronous generator (PMSG)-based wind farm. The linearised equations involving the dynamics of steam turbine generator, wind farm, shunt capacitor, transmission line, and load are derived, and the detailed state matrix formation process pertinent to each component is presented. Taking the IEEE 16-machine-68-bus test system as example, the eigenvalue analysis along with participation factor is applied to investigate the impacts of the series compensation level of transmission line on the modal frequencies and damping ratios of two groups of oscillatory modes of interest: namely, the SS mode of the series-compensated transmission line and the shaft modes of the studied steam turbine generator before and after one of the un-studied steam turbine generators is replaced by the DFIG- or PMSG-based wind farm. Some useful conclusions and comments are drawn.

Energic, Exergic, Exergo‐economic investigation and optimization of auxiliary cooling system (ACS) equipped with compression refrigerating system (CRS)

Heller main cooling tower as air-cooled heat exchanger is used in the combined cycle power plants (CCPP) to reduce the temperature of condenser. In extreme summer heat, the efficiency of the cooling tower is reduced and it lessens performance of Steam Turbine Generation (STG) unit of Combined Cycle Power Plant (CCPP). Thus, the auxiliary cooling system (ACS) is equipped with compression refrigerating system (CRS). This auxiliary system is linked with the Heller main cooling tower and improves the performance of power plant. In other words, this auxiliary system increases the generated power of STG unit of CCPP by decreasing the temperature of returning water from cooling tower Therefore, in the first step, the mentioned auxiliary cooling system (ACS) as a heat exchanger and compression refrigerating system (CRS) have been designed via ASPEN HTFS and EES code respectively. In order to validate their results, these two systems have been built and theirs experimentally obtained data have been compared with ASPEN and EES results. There are good agreements between results. After that, exergic and exergo-economic analysis of designed systems have been carried out. Finally, the compression refrigerating system (CRS) has been optimized via Genetic Algorithm (GA). Increasing in exergy efficiency (ε) from 14.23% up to 36.12% and decreasing the total cost rate (ĊSystem) from 378.2 ($/h) to 308.2 ($/h) are as results of multi-objective optimization.

Forensic Engineering Evaluation of an Allegedly Deficient Steam Turbine Foundation

Forensic engineering as applicable to “construction materials evaluation” was used to investigate a condition where an alleged severe deficiency occurred during placement of concrete for a steam turbine gen-erator (STG) structure in west central Florida. The owner questioned the integrity of the partially completed structure, and demanded removal/replacement of the structure. The author conducted a forensic investiga-tion to determine whether the deficiency was limited to the surface, or if removal and replacement of the structure was warranted.

Mitigation of SSR with STATCOM using Subsynchronous Damping Controller on Series-Compensated Transmission Line

Objective: The phenomenon of Sub Synchronous Resonance (SSR) on series-compensated long transmission line with steam turbine generator results into adverse oscillations. Therefore, occurrence of SSR should be reduced to the lowest possible level. Method/Analysis: In this paper, the use of STATCOM and subsynchronous damping controller (SSDC) is proposed to alleviate SSR. The rotor speed deviation of generator is being captured and given to the STATCOM. The IEEE second benchmark model (IEEE SBM) on SSR is adopted to analyze and validate the proposed controller. For this, the controller is applied on STATCOM, which in turn is regulating the line. Findings: SSR generates due to the presence of frequency other than the nominal frequency in the system. By calculating frequency response and FFT analysis, the resonant frequency present in the system, is calculated. Then conventional STATCOM is applied, which shows that STATCOM with no auxiliary control is not capable of damping the SSR oscillations. But with auxiliary SSDC on same STATCOM, effectively mitigate the SSR. Novelty/Improvement: The SSR alleviation is done by conducting transient simulations using MATLAB environment on detailed three-phase model, which is non-linear in nature. Fast Fourier Transform (FFT) analysis is also performed to demonstrate the capability of proposed controller.

Use of heat pumps in turbogenerator hydrogen cooling systems at thermal power plant

The possible increase in heat power generation efficiency was evaluated through this paper via installation of heat pumps for cooling hydrogen in generator of steam turbine.Using the heat pumps, the biggest part of waste heat from turbogenerator hydrogen cooling systems can be transferred to heat supply system. They are used for heat supply in-house load of a power plant or for any other goal of heat supply as well.All calculations were made for thermal power plant at the branch “Nevsky” “TGC-1” company – CHP-21. The analysis was made for heat pumps with heat capacities of 2 MW and 3 MW. The application of such analysis on CHP was applied by the method of detailed settlement estimation of the impact on CHP operating mode with synchronous calculation of characteristics of heat pump. The analysis was made for different operating mode of CHP. A low potential heat source is the water from hydrogen cooling systems of steam turbine generator.The use of heat pumps for steam turbine generator hydrogen cooling system waste heat salvaging is innovation solution to increase TPP cost-performance ratio. On implementing cycle arrangement with heat pump used for sanitary and service makeup water warming, fuel saving is up to 700 toe/year while heat pump system specified heat power is 3 MW.

A probability uncertainty method of fault classification for steam turbine generator set based on Bayes and Holospectrum

With the rapid development of the machinery and the increasing complexity of the steam turbine generator set, it is a great challenge for the safe and reliable operation of the steam turbine generator set. The uncertainties of fault classification and complicated working conditions become important research fields of steam turbine generator. A probability method on the uncertainty reasoning of fault classification for steam turbine generator is proposed in this paper based on the 2D-holospectrum and Bayesian decision theory. Firstly, Bayesian decision theory is adopted for the preliminary fault estimation on actual risk loss by calculating the loss expectation of each decision. Then, the area ratio of overlap region in 2D-holospectrum and the evidence theory can give the probability of the fault. Framework and model of the uncertainty reasoning are also described in this paper. Finally, the model is verified by the experiment of the rotor vibration on test rig. The results show that the method proposed is feasible for reasoning under imperfect information condition.