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.

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.

Challenges in Designing and Building a 700 MW All-Air-Cooled Steam Electric Power Plant

2011 ◽  
Author(s):  
John T. Langaker ◽  
Christopher Hamker ◽  
Ralph Wyndrum
Keyword(s):  
Power Plant ◽  
Electric Power ◽  
Power Plants ◽  
Combined Cycle ◽  
Air Cooling ◽  
Plant Design ◽  
Auxiliary Equipment ◽  
Turbine Generator ◽  
Plant Equipment ◽  
Dry Cooling

Large natural gas fired combined cycle electric power plants, while being an increasingly efficient and cost effective technology, are traditionally large consumers of water resources, while also discharging cooling tower blowdown at a similar rate. Water use is mostly attributed to the heat rejection needs of the gas turbine generator, the steam turbine generator, and the steam cycle condenser. Cooling with air, i.e. dry cooling, instead of water can virtually eliminate the environmental impact associated with water usage. Commissioned in the fall of 2010 with this in mind, the Halton Hills Generating Station located in the Greater Toronto West Area, Ontario, Canada, is a nominally-rated 700 Megawatt combined cycle electric generating station that is 100 percent cooled using various air-cooled heat exchangers. The resulting water consumption and wastewater discharge of this power plant is significantly less than comparably sized electric generating plants that derive cooling from wet methods (i.e, evaporative cooling towers). To incorporate dry cooling into such a power plant, it is necessary to consider several factors that play important roles both during plant design as well as construction and commissioning of the plant equipment, including the dry cooling systems. From the beginning a power plant general arrangement and space must account for dry cooling’s increase plot area requirements; constraints therein may render air cooling an impossible solution. Second, air cooling dictates specific parameters of major and auxiliary equipment operation that must be understood and coordinated upon purchase of such equipment. Until recently traditional wet cooling has driven standard designs, which now, in light of dry cooling’s increase in use, must be re-evaluated in full prior to purchase. Lastly, the construction and commissioning of air-cooling plant equipment is a significant effort which demands good planning and execution.

An Integrated Steam/Gas Turbine-Generator for Combined-Cycle Applications

1989 ◽  
Author(s):  
J. H. Moore
Keyword(s):  
Steam Turbine ◽  
Gas Turbine ◽  
Power Plants ◽  
Combined Cycle ◽  
Gas Temperature ◽  
Turbine Generator ◽  
Fully Integrated ◽  
Reheat Steam ◽  
Exhaust Gas Temperature ◽  
Steam Cycle

Combined-cycle power plants have been built with the gas turbine, steam turbine, and generator connected end-to-end to form a machine having a single shaft. To date, these plants have utilized a nonreheat steam cycle and a single-casing steam turbine of conventional design, connected to the collector end of the generator through a flexible shaft coupling. A new design has been developed for application of an advanced gas turbine of higher rating and higher firing temperature and exhaust gas temperature with a reheat steam cycle. The gas turbine and steam turbine are fully integrated mechanically, with solid shaft couplings and a common thrust bearing. This paper describes the new machine, with emphasis on the steam turbine section where the elimination of the flexible coupling created a number of unusual design requirements. Significant benefits in reduced cost and reduced complexity of design, operation, and maintenance are achieved as a result of the integration of the machine and its control and auxiliary systems.

Transient Torsional Vibration Due to Suddenly Applied Torque

1972 ◽  
Vol 94 (2) ◽  
pp. 595-601 ◽  
Author(s):  
E. I. Pollard
Keyword(s):  
Torsional Vibration ◽  
Degrees Of Freedom ◽  
Transfer Functions ◽  
Short Circuit ◽  
Sudden Change ◽  
Step Function ◽  
Transient Vibration ◽  
Applied Torque ◽  
Compressor Surge ◽  
The Time Domain

Several instances of gear, coupling, or turbine-bucket failures in systems in which the compressors were subjected to extensive periods of heavy surge suggested the possibility that the transient torsional vibration caused by the surge could have contributed to the failures, and led to this investigation. Calculations of transient torsional vibration during acceleration through resonance and for motor or generator sudden short-circuit is treated in reference [1]. The current paper extends this work to the solution of transient vibration resulting from a suddenly applied aperiodic torque. The suddenly applied torque can be a step function representing motor or generator trip-out and compressor surge, or any other aperiodic function of exponential form. Transfer functions for shaft torques due to a sudden change in torque at any point in the system are given for systems with four degrees of freedom. Rules are given for the relatively easy conversion of the transfer functions from the frequency to the time domain. An approximate method of calculating more complex systems is suggested.

Power Output Fluctuation Analysis of Grid-Connected Wind Turbine-Generator System With Limiting Maximum Power Output

2011 ◽  
Author(s):  
Tetsuya Wakui ◽  
Ryohei Yokoyama
Keyword(s):  
Wind Turbine ◽  
Electric Power ◽  
Power Output ◽  
Power Plants ◽  
Fluctuation Analysis ◽  
Electric Power Output ◽  
Turbine Generator ◽  
Generator System ◽  
Wind Turbine Generator ◽  
Fluctuation Characteristic

The reduction in the power output fluctuation of grid-connected wind turbine-generator systems is strongly required to further increase their total installed capacity in Japan. This study focuses on limiting the maximum electric power output by changing the set point of the power output control as a reduction technique. The influence of limiting the maximum electric power output of a 2 MW-system, which adopts the variable speed operation, on the power output fluctuation characteristic is analyzed through numerical simulation conducted by using an observed field wind data. The focus is on the power output fluctuation, which is important for management of commercial power systems including power plants, of the 2 MW-system with six cases of the maximum electric power output. The results show that limiting the maximum electric power output does not have an influence on the power output fluctuation characteristic and control performance during the pitch angle operation at high wind speeds. However, the year-round simulation reveals that limiting the maximum electric power output brings a tradeoff between the reduction in the power output fluctuation and the generating performance.

scholarly journals One solution of main controller in thermal power plants

2008 ◽  
Vol 18 (1) ◽  
pp. 5-8 ◽  
Author(s):  
Nebojsa Radmilovic ◽  
Slavisa Stojakovic ◽  
Goran Kvascev
Keyword(s):  
Power Plants ◽  
Thermal Power ◽  
Electrical Power ◽  
Thermal Power Plants ◽  
Steam Boiler ◽  
Pressure Regulation ◽  
Turbine Generator ◽  
Generator System ◽  
Transport Delay ◽  
Power Regulation

This paper describes functionality between pressure regulation of steam boiler and electrical power regulation of turbine-generator system at thermal power plants. Importans of this control is essentially in coordinate work mode when these complex and non-linear systems have to work as one integrated entity with tendency to produce electrical power at optimal and stable way. Steam generator - boiler is system with long transport delay and here is recommendation for improving pressure regulation. This regulation realized at thermal power plant nominal power 308MW and given working results in real time. Index Terms - boiler control, combustion control, thermal power plants, PID controller.

Characteristic Study of Torsional Vibration on a Full Size Turbine-Generator Unit

1991 ◽  
Author(s):  
Huang Xiuzhu ◽  
Zhang Xueyan ◽  
Sun Daixia ◽  
Gong Qing
Keyword(s):  
Torsional Vibration ◽  
Vibration Characteristics ◽  
Turbine Generator ◽  
Full Size ◽  
Torsional Response ◽  
Shaft System ◽  
Switch Operation ◽  
Shaft Torque ◽  
Generator Unit

Abstract Taking a 200MW turbine-generator unit and its connected transsmision network as a study object, torsional vibration characteristics of the shaft system caused by faulty synchronization, different disturbances in the network and switch operation were analysed and calculated. The effect of intensive excitation and “fast valve closing” on the torsional response is also discussed. It is concluded that large mechanical torque of shaft system would be encountered if there is a 3-phase fault in the network, and the shaft torque would be reduced to a certain extent by giving the “fast valve closing” if the network experience a fault.

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