Study of Analysis and Experiment for Ability to Withstand DC Bias in Power Transformers

Chen, Dezhi; Feng, Zuren; Wang, Qingpeng; Fang, Liwei; Bai, Baojun

doi:10.1109/tmag.2018.2844208

Cited by 25 publications

(7 citation statements)

References 9 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The core is an important aspect in a transformer and not to mention it has to go through diverse circumstances, with magnetostriction being an inherent property of the material; vibration and noise are embedded with it [3,4]. The harmonic currents induced due to DC bias results in saturation, increased leakage flux, temperature rise in the core leading to local overheating, dielectric breakdown and vigorous electromagnetic vibration in the transformer [1,2]. The magnetic flux in the core varies with variation in the magnitude of DC bias injected to it, which ultimately leads to vibration.…”

Section: Introductionmentioning

confidence: 99%

“…Despite the aforementioned virtues, they are vulnerable to many issues during practical implementation. One of them being introduction of DC bias in the converter transformer arising due to the coupling of AC/DC, imbalance in gating of converters, valve side harmonic disturbances and at times due to geomagnetic storms which may lead to permanent failure [1,2]. Thus, the analysis of the effect of DC bias in converter transformer has become indispensable with the growth of HVDC transmission in modern power systems.…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Modelling of magnetostrictive vibration and acoustics in converter transformer

Yadav

Mehta

2021

IET Electric Power Appl

View full text Add to dashboard Cite

The converter transformers are susceptible to more noise and vibration when compared to power transformers due to the presence of DC bias in the DC transmission line. DC bias occurs mostly due to inaccuracies in valve firing resulting in a small residual DC oscillating around zero. Measurement of magnetostriction becomes significant as it influences the vibration and noise from the core. Hence, a magnetostrictive model of a high-voltage DC converter transformer has been developed. This work analyses the vibration and noise acoustics under such an occurrence. First, the core of the transformer model is designed in the stepped configuration for 240 MVA; then, magnetostrictive vibration is analysed by using suitable modules of COMSOL Multiphysics at different magnitudes of DC bias. The physics of noise has been interfaced using the Acoustics Module, and the results are recorded. Finally, artificial neural network model is developed for the prediction of vibration and noise characteristics of the model. The fitting process of neural network was then remodelled using various optimisation techniques, namely teaching-learning-based optimisation, particle swarm optimisation, biogeography-based optimisation, simulated annealing and binary coded genetic algorithm, and their results were compared to obtain the best-suited method using % mean-squared-error evaluation. This is an open access article under the terms of the Creative Commons Attribution License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited.

show abstract

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Modelling of magnetostrictive vibration and acoustics in converter transformer

Yadav

Mehta

2021

IET Electric Power Appl

View full text Add to dashboard Cite

show abstract

“…The DC withstand voltage test may be adequate for identifying insulation deterioration and detecting leakage currents. In the past, DC withstand voltage tests have been used for the efficient diagnosis of paper insulated cables [4,5,6]. However, as XLPE insulated cables are mainly used now, the VLF tan delta and PD diagnostic methods have been subsequently recommended by the IEEE.…”

Section: Introductionmentioning

confidence: 99%

Cable fault and assessment using multiple frequency autoencoder regression-based reflectometry

Jeon

Joung

Lee

et al. 2022

IEICE Electron. Express

View full text Add to dashboard Cite

The distribution cable may be considered the most critical element for power system operation through the key functions of electricity supplement and control and instrumentation signal transmission. Hence, there is a growing need for cable diagnostic techniques that enable accurate condition monitoring and fault detection in cables where external artifact signals are to be continuously measured. This research presents a technique for detecting cable faults based on autoencoder regression-based reflectometry with multiple frequency sinusoidal signals. Estimations of the reflected signal and preliminary test results of a non-faulty cable are used to train the time-series signal reconstruction and anomaly detection, allowing the distinguishment between a fault-induced reflected signal and various artifacts resulting from noise, input mismatch, or other factors. Experiment results on fault location in bypass cable and the reflected signal discrimination on branched network cable have validated the usefulness of the proposed algorithm.

show abstract

“…By analyzing feedback results from the field operation, numerous studies have conducted in-depth researches in dc bias suppression, including impacts of dc blocking capacitors on the power grid protection [15], [16], dc bias tolerance ability of transformers [17]- [19], and resistor-capacitor combined dc bias protection [20]. In terms of optimal placements and combinations of dc bias suppression devices, Ref.…”

Section: Introductionmentioning

confidence: 99%

A System-Level Suppression Method for DC Bias Based on Reverse Unbalanced Currents in the Same Transmission Section

Lin

et al. 2021

IEEE Access

View full text Add to dashboard Cite

Conventional dc bias suppression strategies mainly rely on a single type of device, such as blocking capacitor or blocking resistance. However, these methods are passive palliatives and cannot restrain dc bias currents from the sources. In the light of this, a system-level suppression method for dc bias is proposed in this paper. The average value of currents flowing through the earth is offset by actively generating unbalanced current through other dc projects in the same transmission section, which will reduce the currents flowing into the neutral transformers and alleviate the negative impacts of dc bias. First, the feasibility of the same section dc continuous power support is analyzed. Then the dc bias suppression strategy based on reverse unbalanced currents is elaborated. By scanning all the theoretical operable solutions of unbalanced current generation modes and the possible switching combinations of blocking capacitors, the optimal dc bias suppression solution is output considering the number of adjusted dc projects, the overload margin of dc projects and neutral dc currents of transformers. The effectiveness and superiority of the proposed method are verified by comparative case studies of the East China power grid. INDEX TERMS DcBias; System-level Suppression Method; Reverse unbalanced currents.

show abstract

Study of Analysis and Experiment for Ability to Withstand DC Bias in Power Transformers

Cited by 25 publications

References 9 publications

Modelling of magnetostrictive vibration and acoustics in converter transformer

Modelling of magnetostrictive vibration and acoustics in converter transformer

Cable fault and assessment using multiple frequency autoencoder regression-based reflectometry

A System-Level Suppression Method for DC Bias Based on Reverse Unbalanced Currents in the Same Transmission Section

Contact Info

Product

Resources

About