Assessment of Long-Term Life Expenditure for Steam Turbine Shafts Due to Noncharacteristic Subharmonic Currents in Asynchronous Links

Tsai, Jong-Ian; Lin, Chia-Hung; Tsao, Ta‐Peng

doi:10.1109/tpwrs.2003.820704

Cited by 21 publications

(25 citation statements)

References 20 publications

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“…This reveals their proportional relationship to the E/M disturbing torque. To prevent the bearing stress from exceeding the material yielding point following a three-phase fault at the generator terminal, the lowest safety factor for different shaft sections is evaluated in Table 5, which is computed in the same manner from [3]. Also the corresponding working stress in various shafts is listed in the table.…”

Section: Effect Of the E/m Disturbing Torquementioning

confidence: 99%

“…Recently, the impact of small-signal electrical disturbances has received more and more attention [2,3]. Because these small disturbances are sustained and even lead to resonant oscillations, the cumulative long-term damaging phenomena should not be ignored, e.g.…”

Section: Introductionmentioning

confidence: 99%

“…Because these small disturbances are sustained and even lead to resonant oscillations, the cumulative long-term damaging phenomena should not be ignored, e.g. power system unbalance [2], harmonics induced by asynchronous (High voltage direct current) HVDC links [3] or SERIMDs.…”

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Long-Term Fatigue Life Expenditure of Turbine Shafts Owing to Noncharacteristic Harmonics Produced by Slip Energy Recovery Induction Motor Drives

Tsai

2008

JMMP

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In this paper, the long-term effect of noncharacteristic harmonics resulting from a slip energy recovery induction motor drive (SERIMD) on the fatigue life expenditure of turbine-generator shafts is analyzed. A feed-water pump (FP) in power plants is one of the most essential pieces of auxiliary equipment and consumes considerably large quantities of energy. An SERIMD has many advantages and is an adequate candidate for the purpose of variable speed control. However, it gives rise to sustainable variable frequency subharmonics which induce electromechanical subsynchronous oscillations in turbine shafts through proposed deductions. Accordingly, the author has determined that the long-term effect of these subharmonics is a cause of fatigue damage on turbine shafts even under normal operating conditions through fatigue life estimation.

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Section: Effect Of the E/m Disturbing Torquementioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Long-Term Fatigue Life Expenditure of Turbine Shafts Owing to Noncharacteristic Harmonics Produced by Slip Energy Recovery Induction Motor Drives

Tsai

2008

JMMP

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“…Expanding transmission systems utilize series capacitor compensation or high-voltage direct current systems which all increase the risk of torsional vibration induced fatigue damage [1,2]. Operators are required to ensure ever higher levels of reliability and availability in an environment where the reserve margins of installed capacity are decreasing, plant is aging and the opportunity for maintenance is limited.…”

Section: Introductionmentioning

confidence: 99%

A comparative study of finite element methodologies for the prediction of torsional response of bladed rotors

Scheepers

Heyns

2016

J Mech Sci Technol

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The prevention of torsional vibration-induced fatigue damage to turbo-generators requires determining natural frequencies by either field testing or mathematical modelling. Torsional excitation methods, measurement techniques and mathematical modelling are active fields of research. However, these aspects are mostly considered in isolation and often without experimental verification. The objective of this work is to compare one dimensional (1D), full three dimensional (3D) and 3D cyclic symmetric (3DCS) finite element (FE) methodologies for torsional vibration response. Results are compared to experimental results for a small-scale test rotor.It is concluded that 3D approaches are feasible given the current computing technology and require less simplification with potentially increased accuracy. Accuracy of 1D models is reduced due to simplifications but faster solution times are obtained. For high levels of accuracy model updating using field test results is recommended.

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“…The EAF feeder currents in phases-bc can be represented by the equations (5) and (6 ( 6) where, f s is the system frequency, I h and f h are amplitude and frequency of subsynchronous current produced by EAF, β is phase difference between voltage and current at EAF feeder. The components f s +f h and f s -f h in frequency spectrum are obviously super and SSFs, respectively.…”

mentioning

confidence: 99%

Impact of Torsional Resonance in Turbine-Generator Shaft Due to Multiple EAF Operation

Islam¹,

Chowdhury²

2017

IOSR JEEE

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Among the many nonlinear loads, electric arc furnace (EAF) is a potential source of sub-harmonic currents. Again, turbine-generator (T-G) shaft possesses natural frequencies in the sub-synchronous/subharmonic range. If those sub-harmonic frequencies match to natural frequencies there occur amplification of torsional oscillating torques transmitted among the masses of T-G shaft. This may lead to damage rotating shaft, especially T-G shaft, in the system. This paper assesses the severity of amplified oscillating torques on T-G shaft due to multiple EAFs connected to same point of common coupling (PCC). This paper also assesses the impact due to relative location of EAFs from power stations. For this purpose, a lumped-mass model of T-G shaft and mathematical model of electric arc have been considered. EAFs have been connected to the same PCC and their effects on T-G shaft have been measured with/without resonant excitation of torsional modes.

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Assessment of Long-Term Life Expenditure for Steam Turbine Shafts Due to Noncharacteristic Subharmonic Currents in Asynchronous Links

Cited by 21 publications

References 20 publications

Long-Term Fatigue Life Expenditure of Turbine Shafts Owing to Noncharacteristic Harmonics Produced by Slip Energy Recovery Induction Motor Drives

Long-Term Fatigue Life Expenditure of Turbine Shafts Owing to Noncharacteristic Harmonics Produced by Slip Energy Recovery Induction Motor Drives

A comparative study of finite element methodologies for the prediction of torsional response of bladed rotors

Impact of Torsional Resonance in Turbine-Generator Shaft Due to Multiple EAF Operation

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