Shaft Torsional Stress Due to Asynchronous Faulty Synchronization

Mitsche, J.V.; Rusche, P. A.

doi:10.1109/tpas.1980.319835

Cited by 31 publications

(6 citation statements)

References 3 publications

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“…Synchronizing the generator to the other ac power system is very important, considering that an out-of-step breaker closure generates a short-circuit current and high vibrations from the torsional oscillation of the shaft and, finally, goes to the trip condition [6], [7]. Even though there is no detectable physical damage, assuming that the protection system worked properly, the loss of life of the generators and electric equipment is still anticipated [8]. Because of its importance, dual or triple redundancy level of synchronizing protection is often used for large power plants [9].…”

Section: B Synchronization Of Generatorsmentioning

confidence: 99%

Active Synchronizing Control of a Microgrid

Cho

Jeon

Kim

et al. 2011

IEEE Trans. Power Electron.

217

104

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A microgrid is an aggregation of multiple distributed generators (DGs), such as renewable energy sources, conventional generators, and energy storage systems that provide both electric power and thermal energy. Typically, a microgrid operates in parallel with the main grid. However, there are cases in which a microgrid operates in an islanded mode, or in a disconnected state. Islanded microgrid can change its operational mode to gridconnected operation by reconnection to the grid, which is referred to as synchronization. Generally, a single machine simply synchronizes with the grid using a synchronizer. However, the synchronization of microgrids that operate with multiple DGs and loads cannot be controlled by a traditional synchronizer. It is needed to control multiple generators and energy storage systems in a coordinated way for the microgrid synchronization. This is not a simple problem, considering that a microgrid consists of various power electronics-based DGs as well as alternator-based generators that produce power together. This paper proposes an active synchronizing control scheme that adopts the network-based coordinated control of multiple DGs. From the simulation results using Simulink dynamic models, it is shown that the scheme provides the microgrid with a deterministic and reliable reconnection to the grid. The proposed method is verified by using the test cases with the experimental setup of a practical microgrid pilot plant.Index Terms-Energy storage system, microgrid, microgrid central controller (MCC), network-based control, static transfer switch (STS), synchronization.

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Section: B Synchronization Of Generatorsmentioning

confidence: 99%

Active Synchronizing Control of a Microgrid

Cho

Jeon

Kim

et al. 2011

IEEE Trans. Power Electron.

217

104

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“…During synchronization or paralleling of generators, dangerous operational faults can occur if any of the synchronization requirements are not fulfilled [4].…”

Section: Introductionmentioning

confidence: 99%

Instantaneous Specific Protection Method Against Faulty Synchronizations of Synchronous Machines

et al. 2021

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The probability of faulty synchronization of a generator is very small, but not impossible. The main cause of a faulty synchronization is due to wiring errors caused during maintenance or commissioning when voltage transformer and synchronizing equipment are connected or reconnected wrongly. Faulty synchronizations of synchronous generators cause overcurrent and high electromagnetic torque values that can severely damage, not only the generators their selves, but also prime movers and step-up transformers. Moreover, they produce disturbances on the power system such as power oscillations and voltage sags that can end up collapsing the system if it is not cleared quickly. Despite that, conventional synchronous generator protection systems have not a specific function against faulty synchronizations. This paper presents and analyzes a new and specific protection method against faulty synchronizations. The method is based on an instantaneous low setting overcurrent protection that is only activated during synchronizations. Once the synchronization ends, the protection gets disabled in order to allow the increase of the generator power output. Consequently, it minimizes the damages and the disturbance in the power system through rapid detection and tripping. The method has been successfully validated by computer simulations for a thermal power plant 362 MVA turbo-generator, and by experimental tests on a 5 kVA laboratory generation unit.

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“…In this case, material property analysis, analytical stress calculation, and stress concentration analysis allowed the authors to conclude that high stress concentration and scratches produced by rubbing with an annular ring were the main causes of failure. Several researchers have studied shaft torque, even under transient conditions generated during transient electrical phenomena, and have evaluated its effect on shaft fatigue [3][4][5][6][7][8][9][10][11][12][13].…”

Section: Introductionmentioning

confidence: 99%

Structural component fatigue analysis of a hydrogenerator rotor

Casanova

Gutierrez²,

Viveros³

2020

DYNA

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This paper presents a fatigue life calculation for the pole, the rotor rim, and the rotor spoke of a 100 MW hydro-generator. Mechanical and electrical parameters during unit start, with the hydro-generator working at several power levels, and during a load rejection from 100 MW were measured. The measured loads together with centrifugal force, gravity, and magnetic pulling force were included in finite element models to quantify stresses. Also, stresses produced during over-speed, phase-to-ground failure, and phase-to-phase failure were evaluated. A stress history for each element was obtained by fitting the calculated stresses, with the power generation history collected hourly during one year of operation of the machine. Fatigue life calculation was performed by using the stress history along with the Wang-Brown multiaxial fatigue model.

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Shaft Torsional Stress Due to Asynchronous Faulty Synchronization

Cited by 31 publications

References 3 publications

Active Synchronizing Control of a Microgrid

Active Synchronizing Control of a Microgrid

Instantaneous Specific Protection Method Against Faulty Synchronizations of Synchronous Machines

Structural component fatigue analysis of a hydrogenerator rotor

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