Protection of arc furnace supply systems from switching surges

Soysal, Oguz

doi:10.1109/pesw.1999.747355

Cited by 10 publications

(5 citation statements)

References 4 publications

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“…From Fig. 19, the busbar inductance at 500 kHz is estimated as 5 . Taking into account a transformer bushing capacitance of approximately 1 nF, and making use of the measured transformer impedance from Table IV, one can easily derive a transformer inductance of 72.…”

Section: Discussionmentioning

confidence: 99%

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Experimental and Theoretical Analysis of Vacuum Circuit Breaker Prestrike Effect on a Transformer

Popov

Smeets

Sluis

et al. 2009

IEEE Trans. Power Delivery

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Experimental and theoretical analysis of vacuum circuit breaker prestrike effect on a transformerPopov, M.; Smeets, R.P.P.; Sluis, van der, L.; Herdt, de, H.; Declercq, J. Document VersionPublisher's PDF, also known as Version of Record (includes final page, issue and volume numbers) Please check the document version of this publication:• A submitted manuscript is the author's version of the article upon submission and before peer-review. There can be important differences between the submitted version and the official published version of record. People interested in the research are advised to contact the author for the final version of the publication, or visit the DOI to the publisher's website.• The final author version and the galley proof are versions of the publication after peer review.• The final published version features the final layout of the paper including the volume, issue and page numbers. Link to publication Citation for published version (APA):Popov, M., Smeets, R. P. P., Sluis, van der, L., Herdt, de, H., & Declercq, J. (2009). Experimental and theoretical analysis of vacuum circuit breaker prestrike effect on a transformer. IEEE Transactions on Power Delivery, 24(3), 1266-1274. DOI: 10.1109/TPWRD.2009 General rights Copyright and moral rights for the publications made accessible in the public portal are retained by the authors and/or other copyright owners and it is a condition of accessing publications that users recognise and abide by the legal requirements associated with these rights.• Users may download and print one copy of any publication from the public portal for the purpose of private study or research.• You may not further distribute the material or use it for any profit-making activity or commercial gain • You may freely distribute the URL identifying the publication in the public portal ? Take down policyIf you believe that this document breaches copyright please contact us providing details, and we will remove access to the work immediately and investigate your claim. I. INTRODUCTION IT IS well known that during switching highly inductive loads like transformers and motors, under specific conditions, multiple restrikes in the circuit breaker can occur. Multiple restrikes are fast voltage surges which proceed along the cable and reach transformer or motor terminals. Because of different surge impedances at terminals, a wave reflection and absorption takes place. Voltage oscillations which proceed toward windings are continuously superposed by new voltage waves from new upcoming surges. Hence, voltage waveforms along the transformer winding within a particular time interval can have very different amplitude and rate of rise. Their oscillations contain a broad frequency range which can be from a few kilohertz up to a few megahertz. These are unwanted phenomena [15]. This model is based on the measured frequency admittance matrix of the transformer, the elements of which are admittances measured from any provided measuring point in the transformer windings [16]. The advantage o...

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Section: Discussionmentioning

confidence: 99%

“…Taking into account a transformer bushing capacitance of approximately 1 nF, and making use of the measured transformer impedance from Table IV, one can easily derive a transformer inductance of 72. 5 . This implies a frequency of 591 kHz.…”

Section: Discussionmentioning

confidence: 99%

Experimental and Theoretical Analysis of Vacuum Circuit Breaker Prestrike Effect on a Transformer

Popov

Smeets

Sluis

et al. 2009

IEEE Trans. Power Delivery

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“…However, some actions can be taken right at the design level [10][11] to improve the response of the windings against oscillatory system waves. Some of the known methods of controlling winding resonance are:…”

Section: Remedymentioning

confidence: 99%

Effects of low amplitude oscillatory switching transients on EHV grid transformers

Mitra¹,

Chakrabarti

2011

2011 Annual IEEE India Conference

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A section of the Eastern Regional Power Grid in India has been simulated in this paper using Alternative Transient Program (ATP) for the purpose of defining high frequency transient voltages which may occur during various switching events. The investigation reveals that such oscillatory voltages could excite natural frequencies of a 400/220/132 kV power transformer which closely match with the terminal excitation frequencies. Short Time Fourier Transform (STFT) has been used to analyze the frequency contents of the voltage response of the windings. Results of the STFT confirmed the presence of resonant frequency in the 400 kV main winding of the transformer. Reduction in winding voltage stresses under resonance is possible by deploying some remedial measures which have also been suggested in this paper.

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“…Like the conventional RCs, the basis of the PCBRCs is Faraday's law, and a similar set of equations can be derived for the sensor parameters like self-inductance, mutual inductance, quality factor etc. [18][19][20][21][22][23]. Therefore, the induced voltage across the PCBRC is a linear function of the rate of change of the magnetic flux with respect to time, generated by the EAF's transformer current.…”

Section: Introductionmentioning

confidence: 99%

Designing and manufacturing of electric arc furnace currents measurement system in Mobarakeh Steel Company by printed circuit board‐type Rogowski coils

Sadeghi

Samet

Ghanbari

et al. 2022

IET Science Measure & Tech

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This paper deals with the utilization of printed circuit board Rogowski coils (PCBRCs) for differential protection of electric arc furnace (EAF) transformers in Mobarakeh Steel Company (MSC), Isfahan, Iran. Because of a high level of current (in the range of 100 kA) in the EAF transformers in the MSC, employment of differential protection is quite challenging. Conventional current transformers (CTs) cannot offer reliable performance for very high current levels. The PCBRCs are a branch of Rogowski coils (RCs) that can be manufactured with high precision using computer-aided design approaches and have the capability for the measurement of very large currents. In this study, we have designed and manufactured two sets of PCBRCs to measure current in the primary and secondary sides of the EAF's transformers in the MSC. The PCBRCs are followed by a signal condition circuit (SCC) which includes a low-pass filter, amplifier, and voltage-to-current (V-to-I) converter block. Thanks to the SCC, the high current of the transformers can be properly sensed and transmitted over a long cable that connects the PCBRCs to the relay. Furthermore, a novel model is suggested for the EAF that includes characteristics of both time and frequency domain models. The suggested model is developed using a large number of recorded data from the MSC and can model the non-linear and time-variant behaviours of the EAF. The proposed PCBRCs, SCC, and EAF modelling are evaluated by some simulations and experiments in the MSC.

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Protection of arc furnace supply systems from switching surges

Cited by 10 publications

References 4 publications

Experimental and Theoretical Analysis of Vacuum Circuit Breaker Prestrike Effect on a Transformer

Experimental and Theoretical Analysis of Vacuum Circuit Breaker Prestrike Effect on a Transformer

Effects of low amplitude oscillatory switching transients on EHV grid transformers

Designing and manufacturing of electric arc furnace currents measurement system in Mobarakeh Steel Company by printed circuit board‐type Rogowski coils

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