Current induction to structures due to changing magnetic field
Heimonen, Ville (2019)
Diplomityö
Heimonen, Ville
2019
School of Energy Systems, Energiatekniikka
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Julkaisun pysyvä osoite on
https://urn.fi/URN:NBN:fi-fe2019090326488
https://urn.fi/URN:NBN:fi-fe2019090326488
Tiivistelmä
This master’s thesis has been done for GE Grid Solutions Oy and the aim of the thesis was to analyze magnetic fields created by reactor coils in STATCOM and SVC substations. The focus was especially to study the effects of a changing magnetic field to surrounding structures. The thesis should give better understanding, how close to a reactor coil different conductive structures can exist and determine critical values of the magnetic field regarding to this issue. The induced currents can cause problems such as, generate unnecessary losses and cause heating of the structures.
There are two different instances on how the induction of current can occur and cause problems. The current can induce to a structure that forms a whole loop and large amount of magnetic flux crosses the loop window. Notable eddy currents can form to long ferromagnetic structures that are parallel to the external magnetic field.
Laboratory tests and simulations showed that, the higher the material electrical conductivity, the more induced current and losses would be generated to structures that form whole loops. There are many variables that define whether a loop would become a problem in a substation, such as: loop size, material thickness, material electrical conductivity and angle relative to the magnetic field. For ferromagnetic materials, as carbon steel, the eddy currents proved to be more problematic than the induced circulating current through the loop.
There are two different instances on how the induction of current can occur and cause problems. The current can induce to a structure that forms a whole loop and large amount of magnetic flux crosses the loop window. Notable eddy currents can form to long ferromagnetic structures that are parallel to the external magnetic field.
Laboratory tests and simulations showed that, the higher the material electrical conductivity, the more induced current and losses would be generated to structures that form whole loops. There are many variables that define whether a loop would become a problem in a substation, such as: loop size, material thickness, material electrical conductivity and angle relative to the magnetic field. For ferromagnetic materials, as carbon steel, the eddy currents proved to be more problematic than the induced circulating current through the loop.