Current adaptive reactor structure
A transformer for power line reactance injection that can be adapted in manufacturing to different operating current ranges by interchanging primary windings having one, two, three, four or more laminar turns. Through its use of gaps in the magnetic circuit that are filled with high temperature, high thermal conductivity dielectrics, this transformer has tolerance to very high fault currents, and it can be passively cooled by the use of fins on the exterior walls of the core.
1. A system, comprising:
a plurality of transformers for use in a power line reactance injection system, each transformer comprising:
a laminated ferromagnetic core having a laminated ferromagnetic center post;
one or more secondary windings surrounding the laminated ferromagnetic center post; and
a primary winding surrounding the one or more secondary windings;
wherein the primary winding includes N laminar turns of conductors, each laminar turn having a height and a thickness;
wherein a total conducting cross section of the primary winding is N times a thickness of a laminar turn times a height of the laminar turn, and the total conducting cross section of the primary winding is a constant; and
wherein N is a positive integer.
2. The system of claim 1 wherein for each transformer, the primary winding is rectangular in cross section and has a specified height and a specified width configured to fit within the laminated ferromagnetic core and to be external to the one or more secondary windings.
3. The system in claim 1 wherein for each transformer, a primary operating current of the transformer is inversely proportional to the number N of laminar turns of the primary winding of the transformer.
4. The system of claim 1 wherein the respective primary windings of the transformers include different number of laminar turns from one another, thereby resulting in the transformers having different primary operating currents from one another.
5. The system of claim 1 wherein for each transformer, the laminated ferromagnetic core is a rectangular laminated ferromagnetic core having sidewalls, wherein the center post is separated from the sidewalls by gaps at each end of the center post, the gaps being filled with alumina, borosilicate glass, papers made of aramid with inorganic fillers, or glass composites having thermal conductivities in excess of 0.2 W/(mK°).
6. The system of claim 1 further comprising a plurality of enclosures, wherein each transformer is disposed within an enclosure, the enclosure having cooling fins on at least one external surface of the enclosure and being adjacent to at least one sidewall of the laminated ferromagnetic core for passive convection cooling of the laminated ferromagnetic core.
7. The system of claim 1 wherein for each transformer, the laminated ferromagnetic center post of the laminated ferromagnetic core has a plurality of gaps in a magnetic circuit defined by the laminated ferromagnetic core and the laminated ferromagnetic center post.
8. The system of claim 7 wherein the gaps in the laminated ferromagnetic center post are filled with dielectric materials having thermal conductivities in excess of 0.1 watt/(mK°).
9. The system of claim 7 wherein the gaps in the laminated ferromagnetic center post are filled with alumina, borosilicate glass, papers made of aramid with inorganic fillers, or high temperature glass composites useable to temperatures of at least 220° C.