An inrush current reduction technique for multiple inverter-fed transformers

Chen, Yu-Hsing; Yeh, Ming-Yang; Cheng, Po-Tai; Liao, Steven; Tsai, Charles

doi:10.1109/ecce.2011.6064030

Cited by 5 publications

(5 citation statements)

References 8 publications

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“…IEC 60076-3, [17]). In [18], the effectiveness of the sequential prefluxing strategy is experimentally verified for a UPS system feeding multiple transformers.…”

Section: A Synchronous Prefluxing With Power Electronic Convertermentioning

confidence: 99%

Transformer inrush current mitigation concept for hybrid transformers

Burkard

Biela

2017

2017 19th European Conference on Power Electronics and Applications (EPE'17 ECCE Europe)

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Large inrush currents can occur when power transformers are connected to the grid. In the past, a wide range of countermeasures has been developed whereof the application of power electronic converters recently received more attention. With hybrid transformers combining a conventional transformer with a power electronic converter, the elimination of inrush currents can be realized without considerable additional hardware effort. For such hybrid transformers, a novel mitigation procedure is proposed, which is based on the injection of a synchronous core flux before the transformer is connected to the grid. In addition, dedicated demagnetization strategies applicable for grid connected converters with filter elements are presented. The effectiveness of the proposed procedure is verified by comprehensive simulations and a comparison to a conventional method.

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“…IEC 60076-3, [17]). In [18], the effectiveness of the sequential prefluxing strategy is experimentally verified for a UPS system feeding multiple transformers.…”

Section: A Synchronous Prefluxing With Power Electronic Convertermentioning

confidence: 99%

Transformer inrush current mitigation concept for hybrid transformers

Burkard

Biela

2017

2017 19th European Conference on Power Electronics and Applications (EPE'17 ECCE Europe)

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“…Higher-order harmonics present in the inrush current can significantly damage susceptible power electronic devices connected to the system. Consequently, scholars have placed considerable emphasis on mitigating inrush current [4][5][6].…”

Section: Introductionmentioning

confidence: 99%

A Soft-Start-Based Method for Active Suppression of Magnetizing Inrush Current in Transformers

et al. 2023

Electronics

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The occurrence of high-amplitude magnetizing inrush current during the energization of a transformer without load poses significant challenges to the stable operation of both the transformer and the power grid, potentially leading to malfunctions in relay protection devices. This paper analyzes the underlying mechanisms of transformer inrush current and presents a novel approach utilizing a soft-start-based method for effectively suppressing inrush currents. The proposed method employs an inrush current suppressor comprising anti-parallel thyristors and filters to mitigate the adverse effects caused by the inrush current. A comparative study is conducted to evaluate the filtering efficacy of three types of filters incorporated in the inrush current suppressor: an LCLC damping filter, a high-order single trap filter and a high-order double trap filter. Through careful analysis and optimization, the high-order double trap filter with parallel RC damping damper is selected as the optimal configuration. To ensure effective suppression, it is necessary to incorporate a filter at the termination point of the anti-parallel thyristor. Additionally, a closed-loop control strategy is implemented to ensure a smooth start and actively suppress the magnetizing inrush current. To validate the effectiveness of the proposed method, comprehensive simulations are performed using Matlab/Simulink. The results demonstrate the successful suppression of inrush current and the maintenance of stable operation for the transformer. This inrush suppression method does not require considering the influence of residual magnetism and the grounding mode of the transformer’s neutral point. It is also suitable for various transformer structures and wiring methods, which makes it highly applicable.

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“…Although the equipment in critical applications operates around the clock, some auxiliary loads may switch on and off during the day depending on the product production and scheduling. Consequently the transformers in front of them are also switched on and off [2]. A significant transient inrush current, which often occurs when the transformer is energized, can readily be observed during the energizing of these auxiliary loads and causes a temporary voltage drop which could trigger the over-current protection of the UPS system.…”

Section: Introductionmentioning

confidence: 99%

“…Alternatively, a method involving maintenance of the flux linkages of the main and auxiliary load transformers through closed-loop flux compensation [2] could be adopted. However the inrush current phenomenon still persists although with a reduced magnitude.…”

Section: Introductionmentioning

confidence: 99%

An Inrush Current Elimination Technique for Line-interactive UPS Systems During Switching-in of an Auxiliary Load While Feeding a Main Load

Bukhari

Kwon

Lipo

2014

7th IET International Conference on Power Electronics, Machines and Drives (PEMD 2014)

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Most industrial facilities involve use of various types of auxiliary loads in addition to a main sensitive load. Each of these loads are generally accompanied by load transformers. As these auxiliary loads are switched-in, their transformers also become energized. An inrush current often develops when the transformer is switched-in. This paper proposes an inrush current elimination technique for line-interactive UPS systems during the switching-in of auxiliary load transformers by utilizing a fast acting current regulated voltage source inverter. The proposed inrush current elimination technique is validated by simulation results.

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An inrush current reduction technique for multiple inverter-fed transformers

Cited by 5 publications

References 8 publications

Transformer inrush current mitigation concept for hybrid transformers

Transformer inrush current mitigation concept for hybrid transformers

A Soft-Start-Based Method for Active Suppression of Magnetizing Inrush Current in Transformers

An Inrush Current Elimination Technique for Line-interactive UPS Systems During Switching-in of an Auxiliary Load While Feeding a Main Load

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