Turbo Generator Research Articles

Damping Shaft Torsional Oscillations in Dual Excited Turbo Generators

Technical advantages of utilizing the two field systems of the Dual Excited Synchronous Generator (DESG) for damping inertial and unstable torsional modes of steam turbo-generators (T-G) are considered. This is achieved by adding two auxiliary controllers, one on each field system. The d- axis auxiliary controller is designed to enhance the stability of the inertial oscillatory mode while the q-axis controller is designed to damp the unstable torsional modes. A comparison is made between using either generator or high-pressure turbine speed deviations as the stabilizing signals for the two controllers. The study is conducted on system-1 of the second IEEE benchmark for the simulation of the sub-synchronous oscillations. A rigorous state space mathematical model has been developed and simulated using MATLAB to carry the sought investigations. The pole placement method is used to determine the controller parameters. The results indicate that coordination of the two controllers can significantly increase the power system damping for the inertial and torsional oscillatory modes.

End winding deformations in different turbo generators during 3-phase short circuit and full load operation

The measurement and calculation of end winding deformations for different turbo generators is presented. The measurements have been realized on three turbo generators of ratings from 94 MVA to 550 MVA. They have been done both for full load operation and for a three phase short circuit and were compared with calculation results. The nonlinearity and the influence of temperature on amplitudes and frequencies of the deformations is investigated.

Theoretical analysis of lateral response due to torsional excitation of geared rotors

This paper is concerned with lateral response of geared rotors due to torsional excitation. Usually torsional response is determined due to excitation torque, such as short circuit torque, to determine the safety of a turbo generator set and the coupling of bending and torsion in such an analysis is ignored. Such an analysis gives an accurate prediction only when the bending natural frequencies are not close to the spin speed and its higher as well as lower orders. In this work, the coupling between bending and torsion due to gears as well as the effect of axial torque on bending vibrations is taken into account to determine the coupled lateral and torsional response due to torsional excitation. Examples are given which illustrate the importance of such coupling mechanism giving rise to large amplitudes of bending vibrations which may be harmful to the operation of geared turbine rotors. The effect of axial torque is shown to be less significant, even when the rotor runs at the bending natural frequency and is subjected to a short circuit torque.

Aspects of the Hard- and Software Environment of Transputer Based Non Linear Real Time Observers for Control and Diagnostics of Large Turbo Generator Sets

The introduced paper illustrates the main aspects of the software- and hardware structures of a distributed realized transputer based state reconstuction system for large turbo generator sets. The complete system makes use of the distributed computing power of a transputer network, data acquisition hardware and a suitable software concept. It consists of 7 transputers on which several parallel processes are distributed, like: structured data handling, solving and integration of non linear differential equation systems, control of coloured visualisation and animation schemes, preparation and upgrading of measured and reconstructed states. This system has been tested successfully in a combined gas an steam power station (CGS).

Production and characteristics of high-current superconductors

High-current (10–50 kA) superconductors are needed for large magnet systems especially in nuclear fusion research and high energy accelerators but also for other applications like turbo generators, MHD and SMES. A survey is given on the design and fabrication of conductors for these applications. The conductors are built up from many individual strands by cabling processes. The strands have to be tailor made to accommodate the operational conditions e.g. by using fine filaments and/or resistive barriers. Fully transposed cables are mainly based on the flat cable concept or on the bundle type cable. Additional stabilizers may be incorporated in the cable design to provide protection in case of a quench. For very large magnets reinforcing members are required. In case of internally cooled conductors the outer conduit can be used simultaneously as reinforcement.

Life estimation of gear transmission unit in a turbine generator set due to short circuits

This paper is concerned with the dynamic analysis of a gear transmission system in a turbo generator set and life estimation of the gears due to short circuits in the generator. The dynamic analysis of a turbo generator set is first briefly outlined to determine the torsional natural frequencies and mode shapes. An equivalent three mass system is derived for obtaining the transient response. The description of torque generated due to short circuits in the generator is then briefly presented. The response obtained as a function of time due to a sudden short circuit is then presented. Using a typical turbo generator set, the performance of gears in the transmission unit under normal torque conditions is first studied regarding their satisfactory performance. The transient response of the gear box is then taken into account to determine the number of electrical short circuits the turbo generator set can withstand. The methods used in this analysis are briefly described during the procedure.

The Curacao KAE-LT-MED and auxiliary steam turbine project: A model for dual purpose MSF plants replacement

KAE, the water and power company of Curacao, has contracted to replace its older and less efficient MSF plants with a 10,000 m 3/day Low Temperature, Horizontal Tube, Falling Film, Multi Effect Distillation (LT-MED) plant. The plant operates at a top brine temperature of 70 degrees C and requires steam at only 0.34 bar a. However, motive steam is available, as extraction from the power station's turbines, at 2.55 bar a, 155 °C, as required by the higher temperature MSF plant. This excess pressure potential is used to generate 3.1 MW of power in an auxiliary low pressure steam turbo-generator, thereby improving overall economy and lowering desalted water cost to a level unequalled by any other system. The paper describes the power station turbine, auxiliary low pressure turbo generator and LT-MED plant combined scheme, its operational features and economics.

大形排ガスエコノマイザスートファイアの研究と防止対策実施例

On a diesel ship provided with an exhaust gas economizer, there are problems with soot fire which occurs in the economizer itself and safety against fired soot exhausted from the funnel.Not only ship owners and ship builders but also persons concerned have placed great importance on the soot fire and taken preventive measures. It, however, remains an unsolved problem.This report covers;1) investigation of the process of occurrence of soot fire2) preventive measures against soot fire3) the effect achieved by the preventive measuresOn a container ship which has a steam turbo generator plant by a large exhaust gas economizer.The preventive measures against soot fire given in this report is not effective on all kind of exhaust gas economizer plants, but shows a guideline for preventing soot fire.

Contribution of Power System Stabilizers to the Damping of Torsional Oscillations of Large Turbo Generators

ABSTRACT In this paper, the damping torque contributions of power and speed based stabilizers and the effects of these damping torques on the torsional oscillations of large turbo-generators have been investigated under various operating conditions. The results of these investigations show that, in the case of uncompensated power systems, the power based stabilizers introduce almost no damping in the torsional frequency range while the speed based stabilizers contribute large negative damping torques. However, In the case of series capacitor compensated power systems, both power and speed based stabilizers may contribute negative damping in the frequency range of the torsional oscillations of the turbo-generators under certain operating conditions. However, under different operating conditions, power based stabilizers may also contribute relatively large positive damping in the torsional frequency range. The contribution of positive or negative damping by these stabilizers depends on the series capacitor ...

省エネルギ型軸発電動機制御システム

For reducing the operating cost of ships, the turbo generator is an effective measure for utilizing the waste heat energy contained in the exhaust gas of the main engine, which generates the electrical power required on board the ship.The parallel operation of the turbo generator and the shaft generator/motor is applied to utilize this waste heat energy of the main engine to the fullest possible extent. By applying this system, the following merits are obtained.(1) Using the waste heat energy of main engine as much as possible.(2) Operating the shaft generator/motor as the shaft motor, reduce the fuel consumption of the main engine.(3) Operating the shaft generator/motor as the shaft generator, compensate for the shortage electrical power.The energy saving shaft generator/motor control system introduced in this paper is characterized by stepless operation of the shaft generator/motor by means of the steam control valve lift, making it possible to recover the waste heat energy as much as possible.

Effect of Excitation Control on Subsynchronous Resonance in Series-Compensated Transmission Systems

The problem of subsynchronous resonance, which can occur either in the form of higi frequency or low frequency self-excited oscillations, in a typical unregulated series-compensated transmission system is first studied and, subsequently, the feasibility of suppressing these oscillations through excitation control of synchronous machines is explored. Investigations are carried out through the Routh-Hurwitz technique for the unregulated system, whereas, for the regulated system, effective application of the Parameter plane technique is demonstrated. Analysis for both hydro ana turbo generators reveals that although conventional excitation control schemes can completely suppress low frequency self-excited oscillations, they are found to be helpless in suppressing high frequency self-excited oscillations, The performances of different excitation control schemes are also critically examined. Another important contribution highlights that the transformer (p ψ) terms cannot be neglected in the model for the study of self-excited oscillations, since their omission leads to highly optimistic results.

Application of Solar Energy to Producing Operations of Oil and Gas Fields

Using solar energy to generate limited electrical power for cathodic protection of well casing in the Hugoton and Panoma Council Grove fields protection of well casing in the Hugoton and Panoma Council Grove fields of southwestern Kansas has proved effective. The feasibility of a similar power source for supervisory control systems is being tested in Wattenberg power source for supervisory control systems is being tested in Wattenberg Field, CO. Introduction The basic problems wereto provide better cathodic protection for the casing of 516 old (drilled before 1948) protection for the casing of 516 old (drilled before 1948) Hugoton Field and 125 new Panoma Council Grove Field gas wells than was possible with magnesium anodes, andto provide die supervisory control system used for deliquefying the gas wells with limited electrical power. Cathodic Protection Cathodic protection is required in the Hugoton and Panoma Council Grove fields in Kansas to eliminate Panoma Council Grove fields in Kansas to eliminate corrosion of bare well casing exposed to the highly corrosive water of the Glorietta formation. The cathodic protection cur-rent provided by the magnesium anode protection cur-rent provided by the magnesium anode beds during the past 20 years was not completely adequate. The casing-leak history curve (Fig. 1) shows that casing-leak frequency was reduced by 1963 after magnesium anodes had been installed on 505 wells. However, even though the leak frequency was reduced (64 leaks were experienced instead of the 105 forecast), the 23 leaks experienced during 1963-76 indicated the magnesium anodes were inadequate. This was partially because anodes degrade with time to a zero output in about 10 years. Thus, the level of protective current ranges from an initial high of 1 down to 0 A, with a lifetime average of 0.35 to 0.5 A. Casing-potential profile surveys indicated that the wells actually required a minimum of 1.5 A of current for adequate cathodic protection and confirmed our conclusion drawn from the casing-leak history curve that the magnesium anode beds were inadequate. In 1974, a study was made to determine if an alternative source of direct current power was available, since a major portion of the original magnesium anode beds was expended. Most locations lacked electrical power; if power for a conventional rectifier-powered power; if power for a conventional rectifier-powered cathodic protection system could be brought in, the minimum monthly charge for 5 years would have been as much as $30 for less than $1 worth of power. Thus, an alternative was needed. Thermoelectric generators had been tried unsuccessfully; wind chargers would require excessive maintenance; and a successful turbo generator operated by low gas flow had not been developed. Thus, silicon-cell solar panels with lead-acid storage batteries appeared to be the logical solution, if economically feasible. Comparing solar costs with magnesium anode beds for a 30-year period (Table 1) indicated that solar power systems were economically feasible and could power systems were economically feasible and could provide adequate cathodic protection, thus eliminating provide adequate cathodic protection, thus eliminating casing leaks and the resulting costs to repair or replace the wells. Therefore, a 6-month test of 30 solar-powered cathodic protection systems began Oct. 1974. These installations performed flawlessly after initial problems were corrected. JPT P. 151

Superconducting generator technology-an overview

Application of superconducting technology to the field windings of large ac generators provides virtually unlimited field capability without incurring resistive losses in the winding. Several small-scale superconducting generators have been built and tested demonstrating the feasibility of such concepts. For machines of much larger capacity, conceptual designs for both 300 MVA and 1200 MVA have been completed. The results of those studies lend credence to the viability of such technology on the larger scale. The development of large, superconducting generators will require a substantial, sustained effort to produce a machine with performance and reliability equal to, or greater than that of conventional generators. However, the potential benefits include increased efficiency, improved steady-state and transient stability, potential for higher voltage machines, improved I <inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</inf> <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> t capability, potential for growth to higher ratings and voltages, reduced size and weight, as well as reduction or elimination of onsite generator fabrication. The Electric Power Research Institute (EPRI) will fund a 300 MVA generator. Designed, engineered and fabricated as a turbo generator, the superconducting machine is to be installed in a powerplant, tested and operated in concert with a prime mover, the steam generator and the auxiliary support systems of the powerplant. This method of demonstration will eliminate the more conventional method of evaluating new generator technology and will provide answers to the viability of operating a superconducting machine and its cryogenic handling systems in a fulltime, demanding environment.

The use of glass fibre/epoxy laminates in large turbo generators

Glass fibre/epoxy laminates are used in large turbogenerators (up to 1300 MW), in particular to support the end windings. The mechanical, thermal and electrical properties depend on the choice of resin, preferably cycloaliphatic, and the use of glass mat or cloth or a mixture between them. The optimum fibre content, 74% by weight, is particularly high. The laminates can be tailored to fit the complex stress systems applied to them. Bolts, rivets and springs must all be made of insulating material and are particularly difficult to design. The manufacture of these laminates and the components is described, together with the long-term behaviour and creep properties.

The Empirical Assumptions of Ricardo's 93 Per Cent. Labour Theory of Value

Over broad long term historical trends, the labour theory of value does retain its essential contact with reality. . . after all, and contrary to (the) weight of received opinion, are the deficiencies of the theory as a general guide to the determination of prices, anything like so grave as they have been alleged to be? After all, the deflection of prices of production from values as determined by man hours ... is not very wide. It remains true that 'in equilibrium' the number of man hours ... is the predominant determinant of the ratios at which these will in the long run tend to exchange.... If this were not so, if say jet liners on which an enormous amount of man hours had been directly and indirectly expended sold for less than bicycles, or if electric kettles fetched more than turbo generators, then we shall have to say the labour theory of value had no contact with reality.2

Dedication of the Parsons Memorial Window

On Thursday, 5 October, Sir Robert Robinson, O. M. , President of the Royal Society, invited the Dean of Westminster to dedicate a Memorial Window, designed by Sir Ninian Comper, to commemorate Sir Charles Parsons, O.M. , F. R. S. , the great scientist who gave us the steam turbine which has led to the turbo generators of present day electric power stations and the turbines which drive the biggest ships of the Royal Navy and the Mercantile Marine. Sir Charles Parsons was born in 1854 and after his death in 1931 the Royal Society set up a committee to arrange an appropriate memorial of which the Window in Westminster Abbey is one outcome. Another is the Parsons Memorial Lecture delivered annually. A third was the contribution of £10,000 towards the Parsons Memorial Library at London House, Bloomsbury, which was opened by H.M. Queen Mary on 3 December 1937. Sir Frank Smith, Chairman of the Royal Society Committee and himself the first Parsons Memorial Lecturer, delivered the Memorial Oration at the Abbey.

Pulverized Fuel-Burning Experiences at Buzzard Point Station

Abstract The Buzzard Point Plant is designed for the ultimate installation of six turbines and six boilers. The initial installation consists of one 35,000-kw single-cylinder, 18-stage turbo generator and two 375,000-lb per hr steam-generating units, each with a capacity of 375,000 lb per hr, fired with unit pulverizers. Particular care was necessary to insure against the emission of dust or cinders from the stacks. A careful analysis of all factors involved, resulted in the selection of pulverized-coal-burning equipment. Operating experience to date has shown, that the gases from the stacks are practically free of dust. Fifty per cent of the ash is caught as slag in the furnace bottom and approximately 50 per cent as fly ash in the electrostatic precipitators. Low-volatile coal from Virginia and West Virginia is burned. These coals require a longer burning time than most other coals. With a furnace heat release of 37,000 Btu per cu ft per hr the combustible material in the fly ash averages 12 per cent. Individual tests at boiler outputs of over 300,000 lb per hr have shown combustible in the fly ash of less than 8 per cent. The combustible in the slag is zero. The combustible loss is, therefore, well below 1 per cent of the coal as fired. The major reasons for this low combustible loss and ability to burn fuel efficiently at such high heat release rates are efficient burners and fine grinding. The mills, which are of the duplex Atrita type, have ground in a single unit mill 25,000 tons of coal without replacement of wearing parts and appear good for several thousand tons more. Detailed performance records are given in the paper. With the duplex-type mill, we have in effect four mills per boiler except for the drive. With one-half of one mill out of service, there is sufficient capacity to operate the turbine at full load and with one mill out, 24,000 kw can be carried. There has been some question in regard to the range of operation attainable with a unit mill installation. Operation of the plant has shown a practical working range of from 35,000-kw nominal load down to 5000-kw nominal load with swings of 5000 kw above the former figure and 2000 kw below the latter figure. The operation at a load of 5000 kw, however, is not without some difficulty. Burners occasionally go out and require very close attention by the operators. Two burners and one-half of one mill are used to carry this load. The combined average for the six-months’ period, January to June, inclusive, shows a boiler steaming efficiency of 84.61 per cent and an overall efficiency of 83.94 per cent. The overall efficiency includes coal for banking, starting, steaming, and unusual operations. Performance and availability records of the boilers are given by months in the paper. Overall plant performance for the six months, January to June, inclusive, was 12,672 Btu per net kilowatthour. Details by months are given in the paper. The plant is designed so that all major operating equipment is confined to two floors with no wall between the boiler and turbine room. This arrangement makes it possible to operate with a watch engineer and three operators. Slag tapping requires an average of one man’s time, four hours every other day.

Reestablishing Excitation of a Loaded Alternator in Parallel with Others

The paper describes operating tests with large turbo generators under load and gives a résumé of answers to a questionnaire, bearing on the phenomena accompanying the interruption of the direct-current excitation supply, followed by reclosing after a short interval. The object of the investigation was to determine, if possible, a reasonably safe operating procedure that could be followed in reestablishing normal conditions on a large turbo generator whose excitation had been interrupted while carrying load. The authors conclude that the reexcitation of a generator without withdrawing it from the bus is a justifiable and safe operating procedure and the one that will restore all conditions to normal in the shortest time. These conclusions have been verified by twelve prearranged tests, five ``experiences'' in the local company and seventeen ``experiences'' by other companies. In all of these cases the field switches have been reclosed without trouble of any kind.

Quick-Response Generator Voltage Regulator Field Tests Made With Oscillograph

This paper describes elaborate and severe field tests made on high-speed excitation equipment used with a 5385-kv-a. turbo generator. Complete oscillograms and curves showing the performance of this equipment are included together with a discussion of the results obtained.

Abridgment of quick-response generator voltage regulator field tests made with oscillograph

This paper describes elaborate and severe field tests made on high-speed excitation equipment used with a 5385-kv-a. turbo generator. Complete oscillograms and curves showing the performance of this equipment are included, together with a discussion of the results obtained.