The magnetic field of a three-phase power line with an ordinary and triangular arrangement of wires

This paper analyzed the influence that divided conductor to electrical fast transient burst. Divided conductor may change the magnetic field distribution around the conductor, but accordingly increased conductors electrical susceptance. The mechanism that the disconnecting switch cut off the power line when the no-load current is at peak and electric arc distinguished when the current pass zero and accordingly restraining measure is proposed. The outcome showed that the model can simulate the electrical fast transient burst in capacitive power line and makes it easy to analysis complex power system problems based on simple model. The method is proved to be correct and enforceable by validation of protective measures.

Download Full-text

Procedure for Verifying Population Exposure Limits to the Magnetic Field from Double-Circuit Overhead Power Lines

Electricity ◽

10.3390/electricity2030021 ◽

2021 ◽

Vol 2 (3) ◽

pp. 342-358

Author(s):

Marco Landini ◽

Giovanni Mazzanti ◽

Riccardo Mandrioli

Keyword(s):

Magnetic Field ◽

Three Dimensional ◽

Field Measurements ◽

Power Line ◽

Power Lines ◽

Population Exposure ◽

Exposure Limits ◽

General Validity ◽

The Magnetic Field ◽

Circuit Power

The verification of the limits of the population’s exposure to the magnetic field generated by double-circuit power lines from field measurements carried out on site is not trivial. It requires knowledge of the power line current instant values during the measurement period, the determination of the relationship between current and field at the measurement points (made more complex by the double-circuit overhead line configuration) and the use of that relationship to extrapolate the field values. Nevertheless, the verification of exposure limits for double-circuit power lines from on-site measurements is often conducted with rough, or not particularly stringent, procedures. A practical and straightforward procedure of general validity for non-optimized double-circuit lines is proposed here. No specific measurement position or conductors disposition knowledge is required as well as no complex three-dimensional finite element method code is necessary. The procedure, potentially also applicable to high- and extra-high-voltage lines, is validated on a medium-voltage (15 kV) double-circuit overhead power line study case. Exposure limits assessment suggests that if the line is operated at its rated capacity (230/285 A), the 3 μT quality target is missed. Results are provided with a 95% confidence interval ranging from ±100 nT to ±140 nT in all the cases.

Download Full-text

Rheology and Behavior of Magnetic Fluids in Alternating/Rotating Magnetic Fields

Volume 2: Symposia, Parts A, B, and C ◽

10.1115/fedsm2003-45039 ◽

2003 ◽

Author(s):

Carlos Rinaldi ◽

Xiaowei He ◽

Adam Rosenthal ◽

Thomas Franklin ◽

Cory Lorenz ◽

...

Keyword(s):

Magnetic Field ◽

Magnetic Fields ◽

Magnetic Fluids ◽

Rotating Magnetic Fields ◽

Magnetic Field Rotation ◽

Three Phase ◽

Field Rotation ◽

And Behavior ◽

The Magnetic Field ◽

Cylindrical Test

The rheology and behavior of magnetic fluids in the presence of time-varying magnetic fields is illustrated through three sets of experiments. The first involves measurements of ferrofluid torque on a cylindrical spindle under applied uniform rotating magnetic fields. We measure the torque required to restrain a stationary cylindrical test wall in contact with aqueous ferrofluids subjected to the rotating uniform magnetic field generated by a three-phase AC 2-pole motor stator winding. The torque is found to scale linearly with volume, and to be a function of the applied magnetic field amplitude, frequency and direction of rotation. Measurements show that for ferrofluid entirely inside the cylindrical test wall the torque points in the same direction as the magnetic field rotation pseudovector, whereas for ferrofluid entirely outside the cylindrical wall the torque points in the direction opposite to the field rotation pseudovector. The second set of experiments explores the formation of ordered ferrofluid structures in the gap of a Hele-Shaw cell subjected to simultaneous vertical DC and in-plane horizontal rotating magnetic fields. Finally, the third set of experiments illustrates the effect of applied DC fields on the shape of ferrofluid jets and sheets.

Download Full-text