Real-Time Diagnostic Method of Gas Turbines Operating Under Transient Conditions in Hybrid Power Plants

Author(s):  
Elias Tsoutsanis ◽  
Moussa Hamadache ◽  
Roger Dixon

Abstract The expansion of renewable power plants has transformed the role and operation of gas turbines to a great extent. From the base load operation era, we are moving into a flexible and dynamic engine operation of gas turbines. Advances in computational intelligence have amplified the importance of condition monitoring, diagnostics, and prognostics capabilities in the face of gas turbine operation. Performing diagnostics in transient conditions is beneficial since the gas turbines are now acting as partners of renewables. This article presents a novel diagnostic approach for determining the health of a gas turbine when it works in conjunction with a wind farm in a hybrid power plant. In this article, we propose a model-based diagnostic method without reconstructing component maps according to their degradation. Once the engine model is adapted to its clean condition, it is tuned in real-time to reflect the changes in both the operation and degradation with respect to a benchmark engine model. Time evolving multiple component degradation scenarios are simulated to test the accuracy and efficiency of the proposed method. From a bank of simulated measurements, data trending is performed which facilitates the detection of degradation and provides useful conclusions about the health state of the engine. This diagnostic method is suitable for gas turbines that spend most of their life time in part-load and transient operation and it can be a useful tool for gas turbine operators in planning their assets maintenance in a computational efficient and accurate manner.

Author(s):  
Elias Tsoutsanis ◽  
Moussa Hamadache ◽  
Roger Dixon

Abstract Recent expansion of renewable power plants have transformed the role and operation of gas turbines to a great extent. From the base load operation era we are moving into a flexible and dynamic engine operation of gas turbines. In particular, aero derivative engines that have the capacity to start up, shut down in a short time frame are becoming quite popular for both hybrid power plant arrangements and distributed electricity generation. Advances in computational intelligence, such as digital twins, have amplified the importance of condition monitoring, diagnostics and prognostics capabilities in the face of gas turbine operation. Given the dynamic operating profile of the gas turbines, it is of paramount importance to develop, tune and deploy engine models that are accurate and robust to accommodate their nonlinear behavior. Performing diagnostics in transient conditions has recently gained attention, since the gas turbines are acting as partners of renewables and they have a supporting role. Among a family of diagnostics methods, one that has real time capabilities is based on zero-dimensional engine models. This paper present a novel diagnostic approach for determining the health of a gas turbine when it works in conjunction with a wind farm in hybrid power plant. In contrary to our earlier works, where we have mathematically modeled component maps to derive the health of an engine, in this paper we propose a model-based diagnostic method without reconstructing component maps according to their degradation. Once the engine model is initially adapted to its clean condition, it is subsequently tuned in real time to reflect the changes in both the operation and degradation with respect to a benchmark engine model. Time evolving multiple component degradation scenarios for a gas turbine operating in conjunction with a wind farm, are simulated to test the accuracy and efficiency of the proposed method. From a bank of simulated measurements, data trending is performed which facilitates the detection of degradation and provides useful conclusions about the health state of the engine. This diagnostic method is suitable for gas turbines that spend most of their life time in part-load and transient operation and it forms a simple and useful tool for operators in planning their assets maintenance in a computational efficient and accurate manner.


Author(s):  
Nanahisa Sugiyama

This paper describes a real-time or faster-than-real-time simulation of gas turbine engines, using an ultra high speed, multi-processor digital computer, designated the AD100. It is shown that the frame time is reduced significantly without any loss of fidelity of a simulation. The simulation program is aimed at a high degree of flexibility to allow changes in engine configuration. This makes it possible to simulate various types of gas turbine engines, including jet engines, gas turbines for vehicles and power plants, in real-time. Some simulation results for an intercooled-reheat type industrial gas turbine are shown.


Author(s):  
Uwe Krüger ◽  
Jens Hüren ◽  
Stefan Hoffmann ◽  
Werner Krebs ◽  
Patrick Flohr ◽  
...  

Environmental compatibility requires low emission burners for gas turbine power plants. In the past, significant progress has been made developing low NOx and CO burners by introducing lean premixed techniques in combination with annular combustion chambers. Unfortunately, these burners often have a more pronounced tendency to produce combustion-driven oscillations than conventional burner designs. The oscillations may be excited to such an extent that the risk of engine failure occurs. For this reason, the prediction of these thermoacoustic instabilities in the design phase of an engine becomes more and more important. A method based on linear acoustic four-pole elements has been developed to predict instabilities of the ring combustor of the 3A-series gas turbines (Krüger et al. (1999b)). The complex network includes the whole combustion system starting from both compressor outlet and fuel supply system and ending at the turbine inlet. The flame frequency response was determined by a transient numerical simulation (step-function approach). Based on this method, possible improvements for the gas turbine are evaluated in this paper. First, the burner impedance is predicted theoretically and compared with results from measurements on a test rig for validation of the prediction approach. Next, the burner impedance in a gas turbine combustion system is analyzed and improved thermoacoustically. Stability analyses for the gas turbine combustion system show the positive impact of this improvement. Second, the interaction of the acoustic parts of the gas turbine system has been detuned systematically in circumferential direction of the annular combustion chamber in order to find a more stable configuration. Stability analyses show the positive effect of this measure as well. The results predicted are compared with measurements from engine operation. The comparisons of prediction and measurements show the applicability of the prediction method in order to evaluate the thermoacoustic stability of the combustor as well as to define possible countermeasures.


Author(s):  
Elias Tsoutsanis ◽  
Nader Meskin ◽  
Mohieddine Benammar ◽  
Khashayar Khorasani

In fossil fuel applications, such as air transportation and power generation systems, gas turbine is the prime mover which governs the aircraft’s propulsive and the plant’s thermal efficiency, respectively. Therefore, an accurate engine performance simulation has a significant impact on the operation and maintenance of gas turbines as far as reliability and availability considerations are concerned. Current trends in achieving stable engine operation, reliable fault diagnosis and prognosis requirements do motivate the development and implementation of real-time dynamic simulators for gas turbines that are sufficiently complex, highly nonlinear, have high fidelity and include fast response modules. This paper presents a gas turbine performance model for predicting the transient dynamic behavior of an aeroderivative engine that is suitable for both mechanical drive and power generation applications. The engine model has been developed in the Matlab/Simulink environment and combines both the inter-component volume and the constant mass flow methods. Dynamic equations of the mass momentum and the energy balance are incorporated into the steady state thermodynamic equations. This allows one to represent the engine model by a set of first order differential and algebraic equations. The developed Simulink model in an object oriented environment, can be easily adapted to any kind of gas turbine configuration. The model consists of a number of subsystems for representing the gas turbine’s components and the thermodynamic relationships among them. The components are represented by a set of suitable performance maps that are available from the open literature. The engine model has been validated with an established gas turbine performance simulation software. Time responses of the main variables that describe the gas turbine dynamic behavior are also included. The proposed gas turbine model with its dynamic simulation characteristics is a useful tool for development of real-time model-based diagnostics and prognostics technologies.


Author(s):  
Hossein Ghezel-Ayagh ◽  
Robert Sanderson ◽  
Jim Walzak

FuelCell Energy Inc. (FCE) is developing ultra high efficiency Direct FuelCell/Turbine® (DFC/T®) hybrid power plants. Present activities are focused both on the demonstration of the DFC/T concept in small packaged hybrid power generation units for distributed generation, and the design of multi-megawatt (Multi-MW) hybrid systems for the wholesale electric power market. The development of Multi-MW DFC/T systems has been focused on the on the design of power plants with efficiencies approaching 75% (LHV of natural gas). The design efforts included thermodynamic cycle analysis of key gas turbine parameters such as compression ratio. The power plant designs were studied for near-term deployment utilizing the existing commercially available gas turbines and long-term deployment requiring advanced gas turbine technologies. A new fuel cell cluster concept was developed for mechanical design of Multi-MW systems. The concept utilizes the existing one-MW fuel cell modules as the building block for the Multi-MW hybrid systems.


2000 ◽  
Vol 123 (3) ◽  
pp. 557-566 ◽  
Author(s):  
U. Kru¨ger ◽  
J. Hu¨ren ◽  
S. Hoffmann ◽  
W. Krebs ◽  
P. Flohr ◽  
...  

Environmental compatibility requires low emission burners for gas turbine power plants. In the past, significant progress has been made developing low NOx and CO burners by introducing lean premixed techniques in combination with annular combustion chambers. Unfortunately, these burners often have a more pronounced tendency to produce combustion-driven oscillations than conventional burner designs. The oscillations may be excited to such an extent that the risk of engine failure occurs. For this reason, the prediction of these thermoacoustic instabilities in the design phase of an engine becomes more and more important. A method based on linear acoustic four-pole elements has been developed to predict instabilities of the ring combustor of the 3A-series gas turbines. The complex network includes the whole combustion system starting from both compressor outlet and fuel supply system and ending at the turbine inlet. The flame frequency response was determined by a transient numerical simulation (step-function approach). Based on this method, possible improvements for the gas turbine are evaluated in this paper. First, the burner impedance is predicted theoretically and compared with results from measurements on a test rig for validation of the prediction approach. Next, the burner impedance in a gas turbine combustion system is analyzed and improved thermoacoustically. Stability analyses for the gas turbine combustion system show the positive impact of this improvement. Second, the interaction of the acoustic parts of the gas turbine system has been detuned systematically in circumferential direction of the annular combustion chamber in order to find a more stable configuration. Stability analyses show the positive effect of this measure as well. The results predicted are compared with measurements from engine operation. The comparisons of prediction and measurements show the applicability of the prediction method in order to evaluate the thermoacoustic stability of the combustor as well as to define possible countermeasures.


Author(s):  
C. Kalathakis ◽  
N. Aretakis ◽  
I. Roumeliotis ◽  
A. Alexiou ◽  
K. Mathioudakis

The concept of solar steam production for injection in a gas turbine combustion chamber is studied for both nominal and part load engine operation. First, a 5MW single shaft engine is considered which is then retrofitted for solar steam injection using either a tower receiver or a parabolic troughs scheme. Next, solar thermal power is used to augment steam production of an already steam injected single shaft engine without any modification of the existing HRSG by placing the solar receiver/evaporator in parallel with the conventional one. For the case examined in this paper, solar steam injection results to an increase of annual power production (∼15%) and annual fuel efficiency (∼6%) compared to the fuel-only engine. It is also shown that the tower receiver scheme has a more stable behavior throughout the year compared to the troughs scheme that has better performance at summer than at winter. In the case of doubling the steam-to-air ratio of an already steam injected gas turbine through the use of a solar evaporator, annual power production and fuel efficiency increase by 5% and 2% respectively.


2012 ◽  
Vol 2012 ◽  
pp. 1-14 ◽  
Author(s):  
Michele Pinelli ◽  
Pier Ruggero Spina ◽  
Mauro Venturini

A reduction of gas turbine maintenance costs, together with the increase in machine availability and the reduction of management costs, is usually expected when gas turbine preventive maintenance is performed in parallel to on-condition maintenance. However, on-condition maintenance requires up-to-date knowledge of the machine health state. The gas turbine health state can be determined by means of Gas Path Analysis (GPA) techniques, which allow the calculation of machine health state indices, starting from measurements taken on the machine. Since the GPA technique makes use of field measurements, the reliability of the diagnostic process also depends on measurement reliability. In this paper, a comprehensive approach for both the measurement validation and health state determination of gas turbines is discussed, and its application to a 5 MW gas turbine working in a natural gas compression plant is presented.


2016 ◽  
Vol 138 (06) ◽  
pp. 38-43
Author(s):  
Lee S. Langston

This article discusses various fields where gas turbines can play a vital role. Building engines for commercial jetliners is the largest market segment for the gas turbine industry; however, it is far from being the only one. One 2015 military gas turbine program of note was the announcement of an U.S. Air Force competition for an innovative design of a small turbine engine, suitable for a medium-size drone aircraft. The electrical power gas turbine market experienced a sharp boom and bust from 2000 to 2002 because of the deregulation of many electric utilities. Since then, however, the electric power gas turbine market has shown a steady increase, right up to present times. Coal-fired plants now supply less than 5 percent of the electrical load, having been largely replaced by new natural gas-fired gas turbine power plants. Working in tandem with renewable energy power facilities, the new fleet of gas turbines is expected to provide reliable, on-demand electrical power at a reasonable cost.


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