Torsional Robustness of the Combined Cycle Power Train Arrangement: Application of Statistical Methods to Accelerate Shaft-Line Design Cycles

2017 ◽  
Vol 139 (8) ◽  
Author(s):  
Mateusz Golebiowski ◽  
John Ling ◽  
Eric Knopf ◽  
Andreas Niedermeyer
Keyword(s):  
Statistical Methods ◽  
Design Space ◽  
Short Circuit ◽  
Probabilistic Approach ◽  
Combined Cycle ◽  
Power Train ◽  
Shaft Line ◽  
Main Challenge ◽  
Severe Constraint ◽  
Line Design

This article presents the application of statistical methods to guide the rotordynamic design of a turbogenerator shaft-line. One of the basic requirements is all shaft components must survive the event of a short circuit at the terminals of the generator. This is typically assessed via a transient response simulation of the complete machine train (including generator's electrical model) to check the calculated response torque against the allowable value. With an increasing demand of a shorter design cycle and competition in performance, cost, footprint, and safety, the probabilistic approach is starting to play an important role in the power train design process. The main challenge arises with the size of the design space and complexity of its mapping onto multiple objective functions and criteria which are defined for different machines. In this paper, the authors give an example demonstrating the use of statistical methods to explore (design of experiment (DoE)) and understand (surface response methods) the design space of the combined cycle power train with respect to the typically most severe constraint (fault torque torsional response), which leads to a quicker definition of a turbogenerator's arrangement. Further statistical analyses are carried out to understand the robustness of the chosen design against future modifications as well as parameters' uncertainties.

Torsional Robustness of the Combined Cycle Power Train Arrangement: Application of Statistical Methods to Accelerate Shaft-Line Design Cycles

2016 ◽  
Author(s):  
Mateusz Golebiowski ◽  
John P. C. W. Ling ◽  
Eric Knopf ◽  
Andreas Niedermeyer
Keyword(s):  
Statistical Methods ◽  
Design Space ◽  
Short Circuit ◽  
Probabilistic Approach ◽  
Combined Cycle ◽  
Power Train ◽  
Shaft Line ◽  
Main Challenge ◽  
Turbo Generator ◽  
Line Design

This article presents the application of statistical methods to guide the rotordynamic design of a turbo-generator shaft-line. One of the basic requirements is all shaft components must survive the event of a short circuit at the terminals of the generator. This is typically assessed via a transient response simulation of the complete machine train (including generator’s electrical model) to check the calculated response torque against the allowable value. With an increasing demand of a shorter design cycle and competition in performance, cost, footprint and safety, the probabilistic approach is starting to play an important role in the power train design process. The main challenge arises with the size of the design space and complexity of its mapping onto multiple objective functions and criteria which are defined for different machines. In the presented paper, the authors give an example demonstrating the use of statistical methods to explore (Design of Experiment) and understand (Surface Response Methods) the design space of the Combined Cycle Power Train with respect to the typically most severe constraint (fault torque torsional response), which leads to a quicker definition of a turbo-generator’s arrangement. Further statistical analyses are carried out to understand the robustness of the chosen design against future modifications as well as parameters’ uncertainties.

Rotordynamic Investigation of Spiral Vibrations: Thermal Mode Equation Development and Implementation to Combined-Cycle Power Train

2014 ◽  
Author(s):  
Mateusz Golebiowski ◽  
Rainer Nordmann ◽  
Eric Knopf
Keyword(s):  
Heat Exchange ◽  
Heat Input ◽  
Hot Spot ◽  
Quantitative Description ◽  
Combined Cycle ◽  
Thermal Mode ◽  
Power Train ◽  
Thermally Induced ◽  
Shaft Line ◽  
Slip Ring

Rotation of vibration vector caused by thermally induced unbalance changes is a frequently observed phenomenon in large rotating machinery. The heat arising from the friction losses, which are generated at the interfaces between rotating and statoric components of the machine, is partly absorbed by the shaft. This heat input is typically not uniform around the shaft circumference and the resulting temperature difference causes the rotor to bow. The excitation resulting from the sum of mechanical unbalance and thermal bow will lead to a slowly rotating (in the synchronously rotating coordinates system) whirl vector, whose magnitude can decrease or increase in time. A generic understanding of this effect (B.L. Newkirk in 1926, [4]) had been followed by a number of physical models representing specific heat exchange mechanisms (W. Kellenberger [3], J. Schmied [6], P. Morton [11]). A hot spot on the shaft surface can be generated at various locations of a shaft-line. Typical components responsible for thermally induced modulation of vibration vector are journal bearings, seal rings, labyrinth seals (in case of a soft rubbing). Furthermore carbon brushes sliding on the slip ring, supplying the DC current to the field winding of the generator rotor, were identified as a source of nonuniform heat input that may excite spiral vibrations (L. Eckert and J. Schmied in [7], [8]). These local heat input phenomena affect consequently the vibration behavior of the overall shaft train. This paper provides a new approach to the quantitative description of a heat exchange mechanism which leads to the hot spot generation on the surface of a slip ring. A new thermal equation has been formulated, which determines the stability and frequency of the thermal mode. Characteristics of spiral vibration are discussed based on the analytical solution of the Jeffcott rotor model coupled with the proposed thermo-elastic equation. The implementation of the described method to a full shaft-line model of a combined cycle, single shaft power train was done using the Finite Element Method. The results of this calculation were validated against measurement data. The paper shows how the applied computational approach can be used to extend stability margin of the spiral vibration in turbo-generator shaft trains.

scholarly journals Conceptual Mean-Line Design of Single and Twin-Shaft Oxy-Fuel Gas Turbine in a Semiclosed Oxy-Fuel Combustion Combined Cycle

2013 ◽  
Vol 135 (8) ◽  
Author(s):  
Majed Sammak ◽  
Egill Thorbergsson ◽  
Tomas Grönstedt ◽  
Magnus Genrup
Keyword(s):  
Mach Number ◽  
Gas Turbine ◽  
Mass Flow ◽  
Rotational Speed ◽  
Gas Turbines ◽  
Combined Cycle ◽  
Fuel Gas ◽  
Power Turbine ◽  
Exit Mach Number ◽  
Line Design

The aim of this study was to compare single- and twin-shaft oxy-fuel gas turbines in a semiclosed oxy-fuel combustion combined cycle (SCOC–CC). This paper discussed the turbomachinery preliminary mean-line design of oxy-fuel compressor and turbine. The conceptual turbine design was performed using the axial through-flow code luax-t, developed at Lund University. A tool for conceptual design of axial compressors developed at Chalmers University was used for the design of the compressor. The modeled SCOC–CC gave a net electrical efficiency of 46% and a net power of 106 MW. The production of 95% pure oxygen and the compression of CO2 reduced the gross efficiency of the SCOC–CC by 10 and 2 percentage points, respectively. The designed oxy-fuel gas turbine had a power of 86 MW. The rotational speed of the single-shaft gas turbine was set to 5200 rpm. The designed turbine had four stages, while the compressor had 18 stages. The turbine exit Mach number was calculated to be 0.6 and the calculated value of AN2 was 40 · 106 rpm2m2. The total calculated cooling mass flow was 25% of the compressor mass flow, or 47 kg/s. The relative tip Mach number of the compressor at the first rotor stage was 1.15. The rotational speed of the twin-shaft gas generator was set to 7200 rpm, while that of the power turbine was set to 4800 rpm. A twin-shaft turbine was designed with five turbine stages to maintain the exit Mach number around 0.5. The twin-shaft turbine required a lower exit Mach number to maintain reasonable diffuser performance. The compressor turbine was designed with two stages while the power turbine had three stages. The study showed that a four-stage twin-shaft turbine produced a high exit Mach number. The calculated value of AN2 was 38 · 106 rpm2m2. The total calculated cooling mass flow was 23% of the compressor mass flow, or 44 kg/s. The compressor was designed with 14 stages. The preliminary design parameters of the turbine and compressor were within established industrial ranges. From the results of this study, it was concluded that both single- and twin-shaft oxy-fuel gas turbines have advantages. The choice of a twin-shaft gas turbine can be motivated by the smaller compressor size and the advantage of greater flexibility in operation, mainly in the off-design mode. However, the advantages of a twin-shaft design must be weighed against the inherent simplicity and low cost of the simple single-shaft design.

Use of Unconventional Fuels in Gas Turbines

2000 ◽  
Author(s):  
Dilip K. Mukherjee
Keyword(s):  
Heavy Oil ◽  
Gas Turbines ◽  
Power Plants ◽  
Operating Experience ◽  
Combined Cycle ◽  
Oil Refinery ◽  
Power Train ◽  
And Control ◽  
High Degree ◽  
By Products

In several industrial processes, various hydrocarbons, such as low BTU blast furnace gas, syngas, Naphtha, heavy oil and condensate, are available as by-products or residues. Burning such unconventional fuels for combined cycle power generation can be attractive in certain countries due to their low prices or availability compared to natural gas or distillate. In this paper, design and operating experience of combined cycle power plants burning such unconventional fuels, e.g. Bao Shan in China burning LBTU gas, GVK in India burning Naphtha and Api in Italy burning medium Btu gas from heavy oil (refinery bottom) gasification etc. are discussed. The high degree of manufacturers’ ability to develop such projects and design the required equipment — burners/combustors, CC power train and control systems — is illustrated. In addition, the development of Naphtha and condensate burner for GT13E2 is described in short.

scholarly journals Reliable IPTV Service Delivery Using PIM-SSM Routing

2009 ◽  
Vol 1 (3) ◽  
pp. 495-507 ◽  
Author(s):  
A. Qadir ◽  
M. T. Arefin ◽  
H. E. Sandström
Keyword(s):  
Design Space ◽  
Internet Protocol ◽  
Service Level Agreement ◽  
Service Level ◽  
Routing Algorithms ◽  
Iptv Service ◽  
Main Challenge ◽  
Multicast Traffic ◽  
Internet Protocol Television

Internet Protocol Television (IPTV) is a service where digital TV signal data is delivered by using Internet protocol (IP). Telecom and network operators focus on IPTV service for its fastest growth, lower price for operators and market economy. With the improvement of broadband connection and technology, IPTV will get more and more importance. Main challenge for IPTV service is resiliency and Quality of Service (QoS) to meet the users Service Level Agreement (SLA). The design space for IPTV service in terms of resilient backbone design, routing algorithms and fast failure restoration shall be explored. It is described from DSL FORUM and leading IPTV service-providing companies. In the context of this work, the PIM-SSM was configured and QoS was implemented for tagged VLAN of multicast traffic. IPTV traffic is analysed in ACREO testbed and Norrksen network.Keywords: IPTV; QoS; Multicast; PIM; PIM-SM; PIM-SSM; VLAN.© 2009 JSR Publications. ISSN: 2070-0237 (Print); 2070-0245 (Online). All rights reserved. DOI: 10.3329/jsr.v1i3.2633                 J. Sci. Res. 1 (3), 495-507 (2009) 

scholarly journals Load Flow and Transient Stability Analyses for an Integrated Solar Combined Cycle Station in Iraqi Southern by Using ETAP

2021 ◽  
pp. 5-16
Author(s):  
Ahmed Z. Abass ◽  
Dmitry A. Pavlyuchenko ◽  
Alexandr V. Prokopov ◽  
Saadallah Hussain Zozan
Keyword(s):  
Voltage Stability ◽  
Reactive Power ◽  
Short Circuit ◽  
Power Grid ◽  
Load Flow ◽  
Combined Cycle ◽  
Optimal Position ◽  
Grid Voltage ◽  
Voltage Instability ◽  
Capacitor Banks

Analyses of a power system are important for designing and operating phase execution monitoring and to ensure reliable grid operations by sufficient protection projects settings. In this paper, electrical model of a 340 MW integrated solar combined cycle (ISCC) located in the south of Iraq, is developed by Electrical Transient Analyzer Program (ETAP) and load flow, voltage stability and short circuit analyses are performed. Impact of power grid voltage instability on system buses of the power plant is estimated. Using load flow analysis that use Newton-Raphson algorithm, buses operating at under voltage due to power grid voltage instability are specified and their voltages are improved according to given voltage limitation that are based on buses criticality with regard to loads. On-load tap changers and reactive power compensation are used to improve steady state voltage stability. Optimal position for capacitor banks placement and number of capacitor banks are proposed by using optimal capacitor placement module of ETAP. The use of modern technology and advance planning have a big impact on reducing losses. The article shows that the lack of planning is one of the main causes of energy losses. The parameters of the module also indicate the voltage limits, bus voltage and ratings of available capacitor banks. The voltage limit is set at 95% ≤ V ≤ 110%, and it is global for all buses

A Design Methodology Enabling the Efficient High-Fidelity Design of Combined Cycle Power Plants

2009 ◽  
Author(s):  
Matthew A. Prior ◽  
Ian C. Stults ◽  
Matthew J. Daskilewicz ◽  
Scott J. Duncan ◽  
Brian J. German ◽  
...  
Keyword(s):  
Power Plant ◽  
Conceptual Design ◽  
Design Variable ◽  
Power Plants ◽  
Design Space Exploration ◽  
Design Space ◽  
Space Exploration ◽  
Combined Cycle ◽  
High Fidelity ◽  
Run Time

The demand for greater efficiency, lower emissions, and higher reliability in combined cycle power plants has driven industry to use higher-fidelity plant component models in conceptual design. Normally used later in preliminary component design, physics-based models can also be used in conceptual design as the building blocks of a plant-level modeling and simulation (M&S) environment. Although better designs can be discovered using such environments, the linking of multiple high-fidelity models can create intractably large design variable sets, long overall execution times, and model convergence limitations. As a result, an M&S environment comprising multiple linked high-fidelity models can be prohibitively large and/or slow to evaluate, discouraging design optimization and design space exploration. This paper describes a design space exploration methodology that addresses the aforementioned challenges. Specifically, the proposed methodology includes techniques for the reduction of total model run-time, reduction of design space dimensionality, effect visualization, and identification of Pareto-optimal power plant designs. An overview of the methodology’s main steps is given, leading to a description of the benefit and implementation of each step. Major steps in the process include design variable screening, efficient design space sampling, and surrogate modeling, all of which can be used as precursors to traditional optimization techniques. As an alternative to optimization, a Monte Carlo based method for design space exploration is explained conceptually. Selected steps from the methodology are applied to a fictional but representative example problem of combined cycle power plant design. The objective is to minimize cost of electricity (COE), subject to constraints on base load power and acquisition cost. This example problem is used to show relative run-time savings from using the methodology’s techniques compared to the alternative of performing optimization without them. The example additionally provides a context for explaining design space visualization techniques that are part of the methodology.

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