A proposal for the study of voltage sag in isolated synchronous generators caused by induction motor start-up

Silva, Fernando Bento; Vanço, Wagner E.; Gonçalves, Felipe A. da Silva; Bissochi, C.A.; Carvalho, Daniel Pereira de; Guimarães, Geraldo Caixeta

doi:10.1016/j.epsr.2016.05.008

Cited by 18 publications

(12 citation statements)

References 14 publications

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“…However, the negative phase sequence currents will produce, in the air gap, an m.m.f that is moved at the opposite speed to the rotor, with an angular velocity of (−ω). By considering the magnetomotive force of the fundamental component between the stator and the rotor, [24]- [26] is able to mathematically describe this effect:…”

Section: Unbalance In Synchronous Machinesmentioning

confidence: 99%

A Study of the Impacts Caused by Unbalanced Voltage (2%) in Isolated Synchronous Generators

2019

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This paper presents an analysis of the oscillations caused by unbalanced loads in salient pole synchronous generators that operate in isolation under steady state. The oscillatory disturbances, arising from the second-order harmonics, may have or have the potential to cause electromechanical damage to the salient pole synchronous generator. In this paper, the goal is to identify and quantify the magnitude of the electromagnetic torque, which assumes an oscillatory form due to the current component from the negative sequence, caused by unbalanced currents. The self-same analysis was included for second-harmonic voltage oscillations in the qd0 domain, the currents induced on the damper windings together with the oscillation of the load angle and on the field current. These oscillations situated on the synchronous generator are analyzed for a degree of voltage unbalance close to 2% which is an acceptable value according to international regulations for power supply from distribution networks, and this same degree of tolerated voltage unbalance will be used herein for isolated synchronous generators.

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Section: Unbalance In Synchronous Machinesmentioning

confidence: 99%

A Study of the Impacts Caused by Unbalanced Voltage (2%) in Isolated Synchronous Generators

2019

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“…The case of isolated synchronous generator and effect of direct starting-up of asynchronous motor on the magnitude of voltage dip is considered in [11]. The author proposes to use commutated capacitors for reduction of the magnitude and duration of voltage dips, but this does not take into account the influence of other motors and generators, which may be connected to the network.…”

Section: Analysis Of Publications On Research Topicmentioning

confidence: 99%

Development of the system of preemptive control over excitation of a synchronous generator to reduce voltage dips when starting-up asynchronous motors

Al-Suod¹

2018

ELECTROTECHNICAL REVIEW

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The necessity of preliminary estimation of the value of voltage dip arising at starting-up of asynchronous motor commensurate in power with operating diesel-generator sets as part of the ship electric power system is justified. The model of ship electric power system with a modified in real-time mode configuration is developed. The process of direct starting-up of asynchronous motor is simulated, and the values of voltage dips for various values of voltage and time of excitation boost of the synchronous generator are determined. It is established that there are optimum values of the magnitude and time of boosting of excitation voltage of the synchronous generator, where voltage dip in the network is minimal. The obtained results enable assessing in the process of monitoring and management of ship electric power system of the possible consequences of direct starting-up of asynchronous motor on the network voltage under current conditions, and based on them deciding on whether to connect the additional diesel generator to the network or disconnect the least essential consumers of electricity from the network to provide generated capacity reserve. Streszczenie. Zbadano możliwości zapadu napięcia w systemie okrętowtm generatora współpracującego z silnikiem diesla. Symulowano generator asynchroniczny podłączony do sieci dla różnych warunków startu. Określono optymalna wartość napięcia wspomagającego zapewniającą minimalne zapady napięcia. System wyprzedzający sterowania wzbudzeniem generatora synchronicznego umożliwiający zredukowanie zapadów napięcia podczas startu silnika asynchronicznego

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“…Also, they consume a high amount of reactive power during start-up period. As a result, a voltage dip is produced which its amount is directly related to the reactive power need of the motor during start-up [13]. This voltage dip causes a reduction of the motor torque the during start-up period and repeated tripping for relays especially in separated power systems [14].…”

Section: Introductionmentioning

confidence: 99%

“…In a specific installation in which the major load is a 3-phase IM and directly online start-up method is used, the generator rating is sized to the apparent power that is consumed by the motor during the start-up period. Hence, in order to meet the IM power requirements, the generator rating must be sized up to 8-9 times the capacity of the motor power [13]. Hence, high cost is required for the electrical system equipment such as transformers, cables, and circuit breakers as they require to be scaled to the value higher than the required value at steady-state condition to sustain the motor start-up requirements [14].…”

Section: Introductionmentioning

confidence: 99%

Starting of induction motor fed with stand-alone DFIG

et al. 2021

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This paper presents dynamic simulation and control of stand-alone doubly fed induction generator (DFIG) loaded with 3-phase induction motors (IMs). The study reveals that direct on-line starting of large IMs causes a large voltage sag across the generator terminals as the starting current drawn reaches up to 8-9 times the rated load current. Traditionally, this problem has tackled by oversizing of the generator or employment of special starters, under the pretext of mitigating voltage sag. This work explores ways that the starting current can be reduced economically by applying constant V/f control side by side with indirect field-oriented control (FOC) applied on the rotor side converter of the DFIG. This methodology enables starting of larger IMs and mitigation of voltage sag that occurs during the start-up period. Two different rating of IMs loaded with speed-squared mechanical torque are mainly considered. Simulation results of the system behavior under study confirm the capability of the proposed control.

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A proposal for the study of voltage sag in isolated synchronous generators caused by induction motor start-up

Cited by 18 publications

References 14 publications

A Study of the Impacts Caused by Unbalanced Voltage (2%) in Isolated Synchronous Generators

A Study of the Impacts Caused by Unbalanced Voltage (2%) in Isolated Synchronous Generators

Development of the system of preemptive control over excitation of a synchronous generator to reduce voltage dips when starting-up asynchronous motors

Starting of induction motor fed with stand-alone DFIG

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