A controlled switching methodology for transformer inrush current elimination: Theory and experimental validation

Reis, Ana Carla Bittencourt; Oliveira, José Carlos de; Apolonio, R.; Bronzeado, H.S.

doi:10.1109/epqu.2011.6128821

Cited by 10 publications

(5 citation statements)

References 7 publications

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“…Particularly in high voltage scenarios, the deliberate activation of circuit breakers featuring independent pole operation effectively minimizes inrush currents to an insignificant scale, thus eliminating voltage fluctuations within the grid. Similarly, in medium voltage applications, the utilization of controlled switching technology, (10) featuring simultaneous pole operation in switchgear, yields optimal mitigation of inrush currents. Although the presence of considerable residual flux within the core amplifies the inrush current observed during random energization of power transformers, the application of Controlled Switching Device (CSD) technology produces a contrary outcome.…”

Section: Strategy Of Inrush Current Mitigationmentioning

confidence: 99%

Eliminating Inrush Current in Transformers using a Residual Flux Control Algorithm

Taha,

Aboalhawa,

Al Badri

2024

Salud, Ciencia y Tecnología - Serie de Conferencias

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Transformers in general turned on by changing the state of the circuit breakers at several times. Usually, the circuit breakers are closed at various times to turn on the transformers. This process results in high inrush currents due to the asymmetric flux produced in the coil. In light of these facts, the purpose of this study is to provide a method for controlling the switching instant that take place during the inrush of a power transformer.The general idea is to calculate the pre-existing magnetic fluxes remaining on the base legs in terms of the three phase voltages. Then, using these data and equations, the optimal operating time is calculated to ensure that the inrush currents are reduced, and adjustment parameters are determined within the controller to obtain the least time difference between the control signals. The system was completely simulated within the MATLAB environment, and the fluxes and currents were shown without and with the controller, the results showed that the method used reduced the effect of the inrush currents with time differences of the order of milliseconds.

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Section: Strategy Of Inrush Current Mitigationmentioning

confidence: 99%

Eliminating Inrush Current in Transformers using a Residual Flux Control Algorithm

Taha,

Aboalhawa,

Al Badri

2024

Salud, Ciencia y Tecnología - Serie de Conferencias

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“…The magnitude of the inrush current value is influenced by various things, one of which is the ignition angle. The magnitude value of the inrush current will be the maximum value when energized with the ignition angle of 0 degrees, 136 and will be the minimum value when energized with the ignition angle of 90 degrees [9].…”

Section: Inrush Currentmentioning

confidence: 99%

Pre-energize Analysis on 3 Phase Transformer by Considering Each Phase Flux

Septiawan

Negara

Pamuji

2019

JAREE

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Inrush current is a transient phenomenon that occurs when a transformer is first energized to a voltage source at no-load conditions. It causes a very high inrush current. Inrush currents can adversely affect the electric power system and can cause improper work of a relay protection errors. The purpose of this study is to determine the amount of inrush current and minimize the amount of inrush current by using the pre-fluxing method.In this study, a test was carried out using a 3-kVA core type 3 phase transformer. This test is done by giving DC flux before the transformer is connected to the voltage source, then the three transformer phases are energized simultaneously at a certain voltage angle so that the inrush current may could be minimized. The test results show that the transformer that is given a DC flux always has a relatively small inrush current. In this test the inrush current is reduced to a minimum value at an ignition angle of 90 degrees with an inrush current value of 0.74 A in phase R, 3.41 A in phase S, and 3.80 A in phase T.

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“…Several solutions external to the toroidal transformers had been proposed for inrush current mitigation such as; use of Negative Temperature Coefficient (NTC) thermistors in primary winding [6], pre-insertion resistors [7], and controlled switching [8]- [10], but all of them will increase the complexity of the system whilst reducing the reliability. Therefore, the robust transformer based solutions are always desirable in the industry [2].…”

Section: Engineermentioning

confidence: 99%

In-Rush Current Mitigation on Toroidal Transformers with Composite Cores

Perera¹,

Karunadasa

Zoysa³

et al. 2019

Engineer

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Toroidal transformers are high performance transformers used in high end applications. The unique toroidal construction drives them for such performance levels, but the gap less core construction itself makes them lag in controlling high inrush currents. Transformer based solutions are always favourable in the industry over the external solutions, but most of the existing transformer based solutions weaken the toroidal transformer's typical superior performance while mitigating the inrush current. This paper investigates an effective inrush current mitigating method with composite cores, while protecting the performance level of typical toroidal transformers and being competitive in the market. The proposed method has two cores made with different steel types which are positioned concentrically, where the inner core is uncut, but the outer core is cut with an air-gap. This paper investigates on the optimum air-gap that should be maintained to minimize the inrush current based on the transformer size and the particular two steel types. Further, this paper describes on the inrush current calculation on composite cores together with the formulae and derived characteristic curves. The results and formulae presented in this paper are verified with laboratory experiments with real transformers, built with composite cores.

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A controlled switching methodology for transformer inrush current elimination: Theory and experimental validation

Cited by 10 publications

References 7 publications

Eliminating Inrush Current in Transformers using a Residual Flux Control Algorithm

Eliminating Inrush Current in Transformers using a Residual Flux Control Algorithm

Pre-energize Analysis on 3 Phase Transformer by Considering Each Phase Flux

In-Rush Current Mitigation on Toroidal Transformers with Composite Cores

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