Integration of enclosure and core for improved structural integrity of an impedance injection unit
Sheet metal construction is described for achieving high strength at low weight for a power reactor and for an impedance injection module incorporating the power reactor. Clamping plates are used to retain the core and the windings of the reactor. Integrated features of a specialized frame of the impedance injection module include flanges for structural rigidity, a convenient yoke plate for lifting by crane, feet for mounting insulators, and sufficient strength to maintain mechanical integrity during normal operation and also during fault conditions. The specialized frame provides a light weight assembly suitable for mounting on power transmission lines as well as on ground assemblies. The specialized frame can reduce the cost of the total enclosure to around 25% of the cost and 50% of the weight of an equivalent conventional enclosure. An insulation topology is also described.
1. An assembly for an impedance injection unit comprising:
a frame having a plurality of sheet metal components, comprising clamping plates and a support bar, arranged for integration of enclosure and core of the impedance injection unit, wherein the frame is to retain an upper laminated core in the shape of a rectangular prism, a central laminated core in the shape of a rectangular prism, a C-shaped laminated core, a toroidal secondary winding surrounding the central laminated core and a toroidal primary winding surrounding the toroidal secondary winding; and
insulation materials; wherein
the plurality of sheet metal components have shapes and bending to provide stiffening and construction having light weight and structural strength sufficient to withstand, without mechanical failure, stress related to a fault current flowing in a series connection of the impedance injection unit in a power transmission line, wherein magnitude of the fault current ranges from 25 kA to 170 kA.
2. The assembly for the impedance injection unit of claim 1 further comprising an attached yoke plate for lifting the impedance injection unit.
3. The assembly for the impedance injection unit of claim 1 further comprising individual feet elements for attaching insulators.
4. The assembly for the impedance injection unit of claim 1 further comprising an attached sheet metal enclosure.
5. The assembly for the impedance injection unit of claim 1 further comprising an attachable corona ring.
6. The assembly for the impedance injection unit of claim 1 further comprising at least one a NEMA (National Electrical Manufacturers Association) connector for connecting to the power transmission line.
7. The assembly for the impedance injection unit of claim 6 , wherein the frame has sufficient strength to maintain mechanical integrity and withstand, without mechanical failure, without mechanical failure a fault current in the power transmission line that creates an induced force exceeding 1,000 pounds at the NEMA connector as a result of the fault current flowing in the series connection having a magnitude that ranges from 25 kA to 170 kA.
8. The assembly for the impedance injection unit of claim further comprising the impedance injection unit, with the frame mechanically coupled to a power transformer of the impedance injection unit, wherein the power transformer comprises:
a top core and an outer core, wherein the top core comprises the upper laminated core;
the central laminated core, magnetically coupled to the top core and to the outer core;
wherein the outer core is the C-shaped laminated core with a left arm and a right arm opposing two sides of the central laminated core, and a bottom arm opposing a base of the central laminated core;
the toroidal secondary winding, surrounding the central laminated core; and
the toroidal primary winding, surrounding the toroidal secondary winding.
9. The assembly for the impedance injection unit of claim 8 wherein the toroidal secondary winding comprises a continuously transposed conductor (CTC) wire with an insulating wrap.
10. The assembly for the impedance injection unit of claim 9 wherein the insulating wrap comprises aramid fibers.
11. The assembly for the impedance injection unit of claim 8 wherein the toroidal primary winding comprises copper foil with an insulation between turns.
12. The assembly for the impedance injection unit of claim 11 wherein the insulation between turns comprises aramid fibers.
13. The assembly for the impedance injection unit of claim 8 wherein the insulation materials comprise insulating sheets disposed between the magnetic core elements and winding elements.
14. The assembly for the impedance injection unit of claim 13 wherein the insulating sheets comprise a flexible laminate having high dielectric strength and high temperature operability.
15. The assembly for the impedance injection unit of claim 14 wherein the flexible laminate comprises FHT Glastic™ material.
16. The assembly for the impedance injection unit of claim 8 wherein the insulation materials comprise an insulating wrap around at least one of the toroidal primary winding and the toroidal secondary winding.
17. The assembly for the impedance injection unit of claim 16 wherein the insulating wrap comprises aramid fibers.