Error Considerations for Turbine-Generator Torsional Vibration Monitoring

2020 ◽  
Author(s):  
Jindrich Liska ◽  
Jan Jakl ◽  
Sven Kunkel
Keyword(s):  
Power Systems ◽  
Torsional Vibration ◽  
Gas Turbines ◽  
Measurement Errors ◽  
Power Plants ◽  
Signal To Noise Ratio ◽  
Vibration Monitoring ◽  
Turbine Generator ◽  
Turbine Generators ◽  
Incremental Encoder

Abstract Turbine-generator torsional vibration is linked to electrical events in the power grid by the generator air-gap torque. Modern power systems are subject to gradual transformation by increasing flexibility demands and incorporation of renewable resources. As a result, electrical transient events are getting more frequent and thus torsional vibration is getting more and more attention. Especially in the case of large steam and gas turbines torsional vibration can cause material fatigue and present a hazard for safe machine operation. This paper freely builds on previous work, where a method for torsional vibration evaluation using an incremental encoder measurement was presented, in that it supplements error considerations to this methodology. Measurement errors such as precision of the rotor encoder manufacturing, choice of the proper sensor, its signal to noise ratio and the error of instantaneous velocity computation algorithm are analyzed. The knowledge of these errors is essential for torsional vibration as there is an indirect and relatively complicated path from the measurement to the final torsional vibration results compared to other kinds of vibration. The characteristics of particular errors of the processing chain are validated both on experimental data from a test rig as well as field data measured on turbine-generators in power plants.

Applying Combined Pinch and Exergy Analysis to Closed-Cycle Gas Turbine System Design

1995 ◽  
Vol 117 (1) ◽  
pp. 47-52 ◽  
Author(s):  
V. R. Dhole ◽  
J. P. Zheng
Keyword(s):  
Power Systems ◽  
Gas Turbine ◽  
Gas Turbines ◽  
Power Plants ◽  
Exergy Analysis ◽  
Energy Savings ◽  
Design Guidelines ◽  
Closed Cycle ◽  
Practical Design ◽  
Pinch Technology

Pinch technology has developed into a powerful tool for thermodynamic analysis of chemical processes and associated utilities, resulting in significant energy savings. Conventional pinch analysis identifies the most economical energy consumption in terms of heat loads and provides practical design guidelines to achieve this. However, in analyzing systems involving heat and power, for example, steam and gas turbines, etc., pure heat load analysis is insufficient. Exergy analysis, on the other hand, provides a tool for heat and power analysis, although at times it does not provide clear practical design guidelines. An appropriate combination of pinch and exergy analysis can provide practical methodology for the analysis of heat and power systems. The methodology has been successfully applied to refrigeration systems. This paper introduces the application of a combined pinch and exergy approach to commercial power plants with a demonstration example of a closed-cycle gas turbine (CCGT) system. Efficiency improvement of about 0.82 percent (50.2 to 51.02 percent) can be obtained by application of the new approach. More importantly, the approach can be used as an analysis and screening tool for the various design improvements and is generally applicable to any commercial power generation facility.

Vibration Monitoring and Fault Diagnosis System of Turbine-Generator

2007 ◽  
Author(s):  
Dongmei Du ◽  
Qing He ◽  
Hong Li
Keyword(s):  
Fault Diagnosis ◽  
Power Plants ◽  
Vibration Monitoring ◽  
Turbine Generator ◽  
Diagnosis System ◽  
Java Applet ◽  
Java Technology ◽  
Fault Diagnosis System ◽  
The Difference ◽  
Batch Data

It is very important to monitor vibration and diagnose fault for the operating safety of turbine-generator. The remote monitor and diagnosis via the cyber-based technology is a necessity. The difference between browser/server mode and client/server mode is discussed. There are many advantages of applying Java technology. Using Java, a vibration monitoring and fault diagnosis system of turbine-generator based on browser/server mode is developed. The functions as well as the structure of the whole system are analyzed. Online transmission of batch data via Internet is presented, especially for different program languages. Java Applet technology is used to develop client program. With double-buffer method, a lot of graphic interfaces of dynamic making online are presented, which are not blinking. It is proved that the system is already adopted and functions well in several power plants.

scholarly journals Advanced Aeroderivative Gas Turbines in Coal-Based High Performance Power Systems (HIPPS)

1998 ◽  
Author(s):  
F. L. Robson ◽  
D. J. Seery
Keyword(s):  
Power Systems ◽  
Gas Turbine ◽  
Gas Turbines ◽  
High Performance ◽  
Power Plants ◽  
Performance Standards ◽  
Combined Cycle ◽  
Advanced Technology ◽  
Early 21St Century ◽  
Near Term

The Department of Energy’s Federal Energy Technology Center (FETC) is sponsoring the Combustion 2000 Program aimed at introducing clean and more efficient advanced technology coal-based power systems in the early 21st century. As part of this program, the United Technologies Research Center has assembled a seven member team to identify and develop the technology for a High Performance Power Systems (HIPPS) that will provide in the near term, 47% efficiency (HHV), and meet emission goals only one-tenth of current New Source Performance Standards for coal-fired power plants. In addition, the team is identifying advanced technologies that could result in HIPPS with efficiencies approaching 55% (HHV). The HIPPS is a combined cycle that uses a coal-fired High Temperature Advanced Furnace (HITAF) to preheat compressor discharge air in both convective and radiant heaters. The heated air is then sent to the gas turbine where additional fuel, either natural gas or distillate, is burned to raise the temperature to the levels of modern gas turbines. Steam is raised in the HITAF and in a Heat Recovery Steam Generator for the steam bottoming cycle. With state-of-the-art frame type gas turbines, the efficiency goal of 47% is met in a system with more than two-thirds of the heat input furnished by coal. By using advanced aeroderivative engine technology, HIPPS in combined-cycle and Humid Air Turbine (HAT) cycle configurations could result in efficiencies of over 50% and could approach 55%. The following paper contains descriptions of the HIPPS concept including the HITAF and heat exchangers, and of the various gas turbine configurations. Projections of HIPPS performance, emissions including significant reduction in greenhouse gases are given. Application of HIPPS to repowering is discussed.

Operational Experience With a 15-MW Gas Turbine Generator in an Iron and Steel Works

1960 ◽  
Author(s):  
F. K. Konig
Keyword(s):  
Gas Turbine ◽  
Gas Turbines ◽  
Operating Experience ◽  
Operational Experience ◽  
Turbine Generator ◽  
Iron And Steel ◽  
Turbine Generators ◽  
Iron And Steel Works ◽  
Basic Philosophy ◽  
Steel Works

The author states the basic philosophy for the installation of gas turbines burning blast-furnace gas in the power-generating systems of an iron and steel works. A description is given of the two gas-turbine generators at the Huttenwerk Rheinhausen, A.G. and their operating experience.

scholarly journals Fuel consumption of thermal power technologies under maneuvering modes

2020 ◽  
Vol 2020 (4) ◽  
pp. 45-49
Author(s):  
V.S. Kobernik ◽  
Keyword(s):  
Power Systems ◽  
Fuel Consumption ◽  
Fluidized Bed ◽  
Thermal Energy ◽  
Gas Turbines ◽  
Power Plants ◽  
Thermal Power ◽  
Electric Energy ◽  
Coal Fuel ◽  
Fluidized Bed Boilers

A characteristic feature of the present day development of power engineering lies in the increase in the unevenness of power systems schedules. The structure of generating powers of Ukrainian energy engineering is overloaded with basic powers and characterized by a sharp deficit of maneuvering wanes. To cover the uneven load of the power system during the operation of existing and construction of new power plants, it is necessary to take into account the possibility of their operation under maneuvering modes. This paper determines the influence of work of power plants i under maneuvering modes on the specific consumption of conditional fuel on the released electric energy at working on gas or coal fuel. Fuel consumption for starting of a unit depends on its type and downtime in reserve. The use of steam–and–gas facilities and gas turbines helps to enhance the maneuverability of power plants. Alternative options for the development of thermal energy are the introduction of gas–piston power plants and power units with fluidized–bed boilers. We present formulas for the calculations of fuel consumption on by power units for start–ups and specific consumptions depending on the load and degree of their involvement to regulating loads for different thermal energy technologies: steam–turbine condensation and district heating power units; steam–and–gas and gas turbine plants; gas piston installations; power units with fluidized bed boilers. For enhancing the maneuverability of power plants, working on fossil fuels, their modernization and renewal of software are necessary. Quantitative assessment of the efficiency of power units and separate power plants during their operation under variable modes is important for forecasting the structure of generating capacities of power systems, the need to introduce peak and semi–peak capacities, the choice of the most profitable composition of operating equipment at different schedules of electrical loads Keywords: thermal power, power unit, maneuverable mode, electrical load, specific fuel consumption

Measuring Torsional Natural Frequencies of Turbine Generators by On-Line Monitoring

2003 ◽  
Author(s):  
Hans D. Giesecke
Keyword(s):  
Torsional Vibration ◽  
Natural Frequencies ◽  
Low Pressure ◽  
Operating Conditions ◽  
Turbine Generator ◽  
Torsional Mode ◽  
Turbine Generators ◽  
Vibratory Response ◽  
On Line ◽  
Torsional Excitation

Large turbine generators have torsional modes of vibration that can be excited from the electrical grid by torques applied through the generator. The most significant of these torques has a frequency at twice the grid frequency and is due to the negative sequence current in the generator caused by operation at unbalanced load or during grid transients. When the twisting modes of the low pressure turbine rotors combine with the vibratory modes of the last few stages of blade rows, and the frequency of the combined torsional mode is close to the frequency of the exciting torques, significant vibratory response of the shaft and blades can occur. The accumulated fatigue damage caused by such vibration over time can result in failure of the blades. Since this low damped torsional vibration can not be seen on any of the plant instrumentation, it can result in the loss of low pressure blades with little or no warning. To ensure that the turbine generator is not susceptible to damage from the torsional vibratory response of these modes, it is necessary to confirm that the torsional frequencies are sufficiently removed from the frequency of the exciting torques when the turbine generator is operating. For a large turbine generator, the torsional modes of concern are often between the 15th to 25th mode of vibration. Analysis techniques may not be able to determine the frequency of these modes within the accuracy required to ensure that they are not excited. The only reliable way to determine the natural frequencies of such modes with sufficient accuracy is to measure them directly while the turbine generator is operating. On-line monitoring is often the preferred approach for such measurements since it does not impact the operation of the plant and it determines the torsional natural frequencies at the plant operating conditions. Torsional natural frequencies tend to change as a function of turbine generator speed while the turbine generator is off-line and as a function of power while the turbine generator is on-line. On-line monitoring uses sensitive instrumentation and time averaging techniques to determine the torsional natural frequencies of a turbine generator from random vibration of the shaft while the turbine generator is operating. Identifying the torsional mode that is associated with each measured frequency requires the combination of a good analytic model of the turbine generator and an understanding of how the torsional frequencies react to specific changes in operating parameters. The analytic and measurement techniques that have been developed through experience and implemented during numerous on-line measurements are described in this paper. These techniques have also been used to determine blade stress response levels to torsional excitation in order to evaluate the susceptibility of a specific turbine generator to damage from torsional vibration. In this regard, there is some evidence that the torsional response of the turbine generator can be amplified by the steam flow through the blade path. Finally, these techniques can be used to evaluate any specific transient that occurs during operation of the plant with respect to its impact on fatigue usage of the turbine blades and shaft. If necessary, modifications can be designed to shift the torsional natural frequencies away from the problem torques once the complete response of the turbine generator to torsional excitation is understood.

scholarly journals The Transient Torsional Vibration Behaviour of a Turbine-Generator System Under Short Circuit Excitation

1996 ◽  
Author(s):  
Dennis S. H. Chan
Keyword(s):  
Torsional Vibration ◽  
Power Plants ◽  
Short Circuit ◽  
Sudden Change ◽  
Combined Cycle ◽  
Turbine Generator ◽  
Generator System ◽  
Torsional Response ◽  
System Vibration ◽  
Short Circuits

Turbine-generator systems are subjected to sudden short circuits. The sudden change of electrical characteristics in these systems can incur very high excitation torques on the components. The excitation depends on the types of short circuits and the electrical properties of the generator, etc. Transient torsional vibration due to generator short circuit is investigated in this paper. Typical short circuit excitation functions are discussed. A modern gas turbine / generator / steam turbine system is used to illustrate the effects of modelling inaccuracies and parameter variations. The acceptance standards for such transient short circuit conditions are generally based on maximum torque transmitted or some kind of allowable shear stress. They cannot be accurately predicted by models which use 1–2 disks (stations) to represent a major machine in a train. Either a more refined model or a better reduction method is needed. Flexible couplings affect the transient torsional response and they must be included in the system vibration analysis. Their influence on the peak transmitted torque has been examined. The selection of couplings for turbine-generator systems in modern combined cycle power plants should be emphasized.

Analysis of Cycle Configurations for the Modernization of Combined Heat and Power Plant by Fitting a Gas Turbine System

2004 ◽  
Vol 126 (4) ◽  
pp. 816-822 ◽  
Author(s):  
Tadeusz Chmielniak ◽  
Gerard Kosman ◽  
Wojciech Kosman
Keyword(s):  
Power Plant ◽  
Power Systems ◽  
Gas Turbine ◽  
Gas Turbines ◽  
Power Plants ◽  
Combined Heat And Power ◽  
Entropy Method ◽  
Electric Power Station ◽  
Thermal Electric Power Station ◽  
Steam Cycle

The application of a gas turbine generally allows to increase the number of possible configurations of cogenerated heat and electrical power systems, which became a significant substitute for classic, coal-fired power plants. They are characterized by better thermodynamical, economical, ecological, and operating indexes. Gas turbine units are also the best option for the modernization of existing power plants. This paper discusses the effectiveness of various technological configurations with gas turbines, which are to be applied during modernization projects of already existing conventional combined heat and power plants. In the analysis enthalpy and entropy methods were applied. Algorithms of the entropy method allow to determine the entropy generation in each section of a combined heat and power (CHP) plant. Several criteria were taken into consideration while analyzing the effectiveness of technological cycle configurations with gas turbines. These include the energy effectiveness, the efficiency of the HRSG and the steam cycle, the efficiency of the whole thermal electric power station, the exergetic efficiency of the HRSG and the steam cycle, and the fuel efficiency index. It was assumed that gas turbines operate under their nominal conditions. The composite curves were also taken into consideration while choosing the type of the turbine. The modernization project tends not to eliminate those existing power plant sections (machines and equipment), which are able to operate further. The project suggests that those units should remain in the system, which satisfy the applied durability criterion. The last phase of the optimization project focuses on the sensibility verification of several steam-gas CHP plant parameters and their influence on the whole system.

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