Direct currents in power transformers

Štork, Milan; Mayer, Daniel

doi:10.2478/jee-2019-0010

Cited by 10 publications

(9 citation statements)

References 12 publications

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“…Core and winding heating caused by the induced current , and short-circuit phenomenon may lead to mechanical damage problems, and the reduced working efficiency of the heat sink will also lead to local overheating of the transformer. Based on this, it is necessary to study the effect of coating on the thermal performance of the transformer objects.…”

Section: Resultsmentioning

confidence: 99%

Robust Superamphiphobic Coating Applied to Grease-Proof Mining Transformer Components

et al. 2023

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The iron core and heat sink in a mining transformer are susceptible to damage from oil spills or the harsh mine environment; the deterioration of oil products in the underground environment and transformers produce massive amounts of harmful liquid substances, which may lead to unnecessary economic losses in drilling engineering. To overcome this issue, a convenient and economical way to protect transformer components was developed. Herein, we proposed an air spray technology at room temperature for the preparation of antigreasy superamphiphobic coatings, which are suitable for bulk metallic glass transformer cores and ST13 heat sinks. The addition of polypyrrole powder effectively improves the thermal conductivity and specific heat of the coating in the range of 50–70 °C. More importantly, the fabricated coating has excellent repellency to liquids, such as water, ethylene glycerol, hexadecane, and rapeseed oil. Meanwhile, the coating has excellent physical and chemical resistance and outstanding antifouling features, which provide a feasible solution for combating grease pollution and corrosion in the mine environment. Taking multifaceted stability into consideration, this work contributes to enhancing the application of superamphiphobic coatings in the fields of protecting transformer components in the harsh environment or during transformer operation faults.

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Section: Resultsmentioning

confidence: 99%

Robust Superamphiphobic Coating Applied to Grease-Proof Mining Transformer Components

et al. 2023

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“…If a magnetic storm then arrives in the area of the transmission system, we can measure the GIC directly on the VHV conductors [3,4]. For example, works [5][6][7][8][9][10][11] deal with the calculation of the size of the GIC in the VHV line. Measurements on 400 kV lines showed that in England the GIC reached a value of 10 to 15 A, while in the Nordic countries up to 200 A, with a duration of up to several tens of minutes [12,13].…”

Section: Geomagnetic Induced Currents In Power Transformersmentioning

confidence: 99%

Contribution to the determination of the effect of magnetic storms on the electric power transmission system

Mayer,

Stork

2024

Journal of Electrical Engineering

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When a magnetic storm hits a power transmission system, quasi-stationary geomagnetically induced currents (GIC) are generated in the high-voltage part of the system. These currents cause semi-saturation of the magnetic circuits of power transformers, which induces current overload in their high-voltage windings and subsequently thermal overload, which can lead to system failures. This rather complex phenomenon was described in [11] by a system of nonlinear differential equations and subsequently solved. This very challenging method is replaced in the present work by a simple approach. It allows not only predicting the imminent danger of system collapse, but gives transformer designers valuable information on how they can counteract this danger.

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“…This phenomenon is called semisaturation of magnetic circuits. The theoretical solution [13] and the investigation of faults in practice [7] to [16] show that the current overload can range from 2.5 times to three times the nominal value. Example.…”

Section: Figure 2: Simple Model Of Transmission Systém: 1 -Generator ...mentioning

confidence: 99%

A New Way of Protection of The Transmission Power System Against The Effects of Magnetic Storms

2022

EESRR

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Severe collapses caused by anomalies in the Earth’s magnetosphere, known as geomagnetic storms, have been reported in the operation of transmission power systems. A semi-saturating phenomenon occurs in which geomagnetic induced currents (GIC) are induced in high voltage lines, which cause the power transformers of the system to be overloaded with current and subsequently also thermally. The presented article describes a device that will either completely eliminate or at least significantly reduce the possibility of a power transformer accident. The essence of this device are frequency filters, which are automatically connected in parallel to the high-voltage windings of the power transformers at the beginning of the magnetic storm and are disconnected after the storm subsides. The online information about the effect of the magnetic storm on the system is provided by the indicator to the control workplace. The proposed equipment can be easily implemented into existing transmission systems.

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Direct currents in power transformers

Cited by 10 publications

References 12 publications

Robust Superamphiphobic Coating Applied to Grease-Proof Mining Transformer Components

Robust Superamphiphobic Coating Applied to Grease-Proof Mining Transformer Components

Contribution to the determination of the effect of magnetic storms on the electric power transmission system

A New Way of Protection of The Transmission Power System Against The Effects of Magnetic Storms

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