Study on Dynamic Response of Torsional Vibration of Turbo-Generator Unit Caused by Short Circuit Fault

2012 ◽  
Vol 566 ◽  
pp. 248-252 ◽  
Author(s):  
Cheng Bing He ◽  
Dong Chao Chen ◽  
Yu Jiong Gu
Keyword(s):  
Torsional Vibration ◽  
Short Circuit ◽  
Dynamic Responses ◽  
Stable Operation ◽  
Two Phase ◽  
Time Frequency ◽  
Turbo Generator ◽  
Complex Morlet Wavelet ◽  
Generator Terminal ◽  
Short Circuit Fault

When short circuit faults happen near power plant or generator terminal, severe transient torque shock will act on the shaft system, which seriously affects the safe and stable operation of the unit. Using the increment transfer matrix method, the dynamic responses of torsional vibrations are calculated in this work. Combined with the complex Morlet wavelet and time-frequency contour map, the time-frequency domain characters of dynamic torque are analyzed. The analyzed results show that the torque value caused by three phase short circuit fault is largest. The order of torque value from high to low is two phase short circuit to ground, two phase interphase short circuit and single phase short circuit. The electric distance between short circuit point and generator is more short, and the torsional vibration is more serious.

scholarly journals Shafting Torsional Vibration Analysis of 1000 MW Unit under Electrical Short-Circuit Fault

2021 ◽  
Vol 11 (19) ◽  
pp. 9205
Author(s):  
Honggang Pan ◽  
Yunshi Wu ◽  
Zhiyuan Pang ◽  
Yanming Fu ◽  
Tianyu Zhao
Keyword(s):  
Short Circuit ◽  
Power Grid ◽  
Two Phase ◽  
Shaft System ◽  
Three Phase ◽  
Speed Fluctuation ◽  
Grid Side ◽  
Generator Terminal ◽  
The Impact ◽  
Short Circuit Fault

Taking a 1000 MW turbine generator as the research object, the short-circuit fault in electrical disturbance is analyzed. Since it is very difficult to carry out fault analysis experiments and research on actual systems, simulation analysis is one of the more effective means of electrical fault diagnosis; the simulation’s results approach the actual behavior of the system and are ideal tools for power system analysis, and can provide an empirical basis for practical applications. The short-circuit fault model of the SIMULINK power system is built to analyze the two types of faults of generator terminals short-circuit and power grid short-circuit. The impact load spectrum, fault current and speed fluctuation between low-voltage rotors were extracted and analyzed. The conclusion is that the impact value of electromagnetic torque at the generator terminal is greater than that on the power grid side. The impact value of a two-phase short-circuit at the generator terminal is the largest, and that of a three-phase short-circuit on the power grid side is the smallest. The transient impulse current of a three-phase short-circuit at any fault point is greater than that of a two-phase short-circuit; the impulse current of the grid side short-circuit is much greater than that of the generator terminal short-circuit; the speed fluctuation and fluctuation difference caused by the three-phase short-circuit in the grid side are the largest. The alternating frequency of the transient electromagnetic force of the four kinds of faults avoids the natural frequency of the torsional vibration of the shaft system, and the torsional resonance of the shaft system in the time domain of the short-circuit fault will not appear. However, after the fault is removed, the residual small fluctuation torque in the system has a potential impact on the rotor system. This research shows an analysis of the structural integrity and safe operation of turbine generator units after a short-circuit fault, which can not only be applied to engineering practice, but also provide a theoretical basis for subsequent research.

Analysis on Torsional Stresses in Turbo-Generator Shafts due to Two-Phase Short-Circuit Fault

2013 ◽  
Vol 397-400 ◽  
pp. 427-430 ◽  
Author(s):  
Yu Jiong Gu ◽  
Jing Xu
Keyword(s):  
Cross Sections ◽  
Safety Management ◽  
Short Circuit ◽  
Target System ◽  
Fe Method ◽  
Two Phase ◽  
Management Level ◽  
Turbo Generator ◽  
Frequency Components ◽  
Short Circuit Fault

Taking a 660MW turbine generator shaft system as a target system, the torsional stresses responses are calculated under two-phase short-circuit fault by the finite element (FE) method which can obtain torsional stresses in local areas accurately. The results show that torsional stresses threaten the safety of shafts appear at the first several cycles of the vibration. And the amplitude of stress in weak cross sections located between the low pressure cylinder and the generator is much greater. In addition, the proportion of torsional stresses frequency components in different sections is distinct. The results are helpful to improve the safety management level of the unit.

scholarly journals Torsional Vibration of a Shafting System under Electrical Disturbances

2012 ◽  
Vol 19 (6) ◽  
pp. 1223-1233 ◽  
Author(s):  
Ling Xiang ◽  
Shixi Yang ◽  
Chunbiao Gan
Keyword(s):  
Transfer Matrix ◽  
Torsional Vibration ◽  
Simulation Analysis ◽  
Short Circuit ◽  
Lumped Mass ◽  
Concentrated Mass ◽  
Dynamical Equations ◽  
Mass Model ◽  
Two Phase ◽  
Turbo Generator

Torsional vibration responses of a nonlinear shafting system are studied by a modified Riccati torsional transfer matrix combining with the Newmark-βmethod. Firstly, the system is modeled as a chain consisting of an elastic spring with concentrated mass points, from which a multi-segment lumped mass model is established. Secondly, accumulated errors are eliminated from the eigenfrequencies and responses of the system's torsional vibration by this newly developed procedure. The incremental transfer matrix method, combining the modified Riccati torsional transfer matrix with Newmark-βmethod, is further applied to solve the dynamical equations for the torsional vibration of the nonlinear shafting system. Lastly, the shafting system of a turbine-generator is employed as an illustrating example, and simulation analysis has been performed on the transient responses of the shaft's torsional vibrations during typical power network disturbances, such as three-phase short circuit, two-phase short circuit and asynchronous juxtaposition. The results validate the present method and are instructive for the design of a turbo-generator shaft.

The Comparative Analysis of SVC and STATCOM on Subsynchronous Oscillation Mitigation

2013 ◽  
Vol 756-759 ◽  
pp. 245-249 ◽  
Author(s):  
Jian Zhang ◽  
Xiang Ning Xiao ◽  
Ben Feng Gao ◽  
Chao Luo
Keyword(s):  
Short Circuit ◽  
Time Domain Simulation ◽  
Subsynchronous Oscillation ◽  
Damping Coefficients ◽  
Torque Coefficient ◽  
Electrical Damping ◽  
The Time Domain ◽  
Generator Terminal ◽  
Short Circuit Fault ◽  
Signal Method

The methods for subsynchronous oscillation mitigation based on SVC and STATCOM are analyzed in this paper. According to the IEEE first benchmark model, the electrical damping coefficients respectively provided by SVC and STATCOM connected at the generator terminal, as well as positive damping condition, are deduced by complex torque coefficient approach. Correlative factors which influence the two positive dampings are compared. The analysis results indicate that the positive damping provided by SVC is proportional to the size of system voltage. The positive damping provided by STATCOM is not affected by the size of system voltage, which is mostly proportional to the subsynchronous voltage produced itself. The controllers of SVC and STATCOM are designed and the positive dampings separately offered by SVC and STATCOM are optimized by phase compensation with test signal method. The time domain simulation reveals that STATCOM has stronger damping ability than SVC in the case of short circuit fault.

Analysis on Torsional Fatigue Life of Turbo-Generator Shafts

2011 ◽  
Vol 467-469 ◽  
pp. 1858-1863 ◽  
Author(s):  
Yu Jiong Gu ◽  
Tie Zheng Jin
Keyword(s):  
Fatigue Life ◽  
High Cycle Fatigue ◽  
Low Cycle Fatigue ◽  
Circuit Simulation ◽  
Short Circuit ◽  
Cycle Fatigue ◽  
Two Phase ◽  
Torsional Fatigue ◽  
Turbo Generator ◽  
The Impact

Both low-cycle fatigue and high-cycle fatigue exist during torsional vibrations, but the impact of high-cycle fatigue has rarely been considered. In this paper, a torsional fatigue life analyzing method used for torsional vibration of turbo-generator shafts has been developed based on Manson-Coffin equation and high-cycle fatigue theory. The method has been used to estimate the torsional fatigue life in the most dangerous section of the shafts in a power plant. The cumulative torsional fatigue damage under two-phase short circuit simulation has been predicted.

scholarly journals Fault Detection of Stator Inter-Turn Short-Circuit in PMSM on Stator Current and Vibration Signal

2018 ◽  
Vol 8 (9) ◽  
pp. 1677 ◽  
Author(s):  
Hong Liang ◽  
Yong Chen ◽  
Siyuan Liang ◽  
Chengdong Wang
Keyword(s):  
Fault Detection ◽  
Wavelet Packet ◽  
Short Circuit ◽  
Permanent Magnet Synchronous Motor ◽  
Vibration Signal ◽  
Frequency Method ◽  
Time Frequency ◽  
Stator Current ◽  
Three Phase ◽  
Short Circuit Fault

The stator inter-turn short circuit fault is one of the most common and key faults in permanent magnet synchronous motor (PMSM). This paper introduces a time–frequency method for inter-turn fault detection in stator winding of PMSM using improved wavelet packet transform. Both stator current signal and vibration signal are used for the detection of short circuit faults. Two different experimental data from a three-phase PMSM were processed and analyzed by this time–frequency method in LabVIEW. The feasibility of this approach is shown by the experimental test.

Fault Diagnose of Rotor Winding Inter Turn Short Circuit in Generator

2013 ◽  
Vol 321-324 ◽  
pp. 1290-1294
Author(s):  
Hai Yan Xiao ◽  
Xue Wu Wang ◽  
Deng Feng Chen
Keyword(s):  
Short Circuit ◽  
Reference Wave ◽  
Magnetic Characteristics ◽  
Wave Form ◽  
Fault Diagnose ◽  
Turbo Generator ◽  
Half Wave ◽  
Wave Forms ◽  
Rotor Winding ◽  
Short Circuit Fault

Based on magnetic characteristics of inter turn circuit of rotor windings in turbo generator, and analysis the principles of detecting coil method. Based on the symmetry of generator structure and magnetic character between stator and rotor, three fault diagnose methods are presented in this paper: Wave form limitations, Half-wave sliding superposition and Reference wave forms. The application example shows that Reference wave forms method is capable of diagnosing inter turn fault, its severity, and especially locating the inter turn short circuit fault.

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