FORM 2
THE PATENTS ACT, 1970
(39 OF 1970)
As amended by the Patents (Amendment) Act, 2005
&
The Patents Rules, 2003
As amended by the Patents (Amendment) Rules, 2006
PROVISIONAL SPECIFICATION
(See section 10 and rule 13)
TITLE OF THE INVENTION
High temperature superconducting transformer winding arrangement for perpendicular
flux reduction
APPLICANTS
Crompton Greaves Limited, CG House, Dr Annie Besant Road, Worli, Mumbai 400 030, Maharashtra, India, an Indian Company
INVENTOR
Vaithiyanathan Ramakichenan, of Product Technology Centre, CG Global R&D Centre, Crompton Greaves Ltd , Kanjur (E), Mumbai 400042, Maharashtra, India, an Indian National
PREAMBLE TO THE DESCRIPTION
The following specification particularly describes the nature of this invention:

FIELD OF INVENTION:
This invention relates to high temperature superconducting (HTS) transformer for
perpendicular flux reduction.
This invention also relates to a method of reducing Alternating current losses in HTS
transformer.
BACKGROUND OF INVENTION:
In the HTS transformer, the liquid nitrogen contacts on one side of the first layer of the HTS coil in a solenoidal winding, which is less than the other side of the layer. This is due to the first layer placed directly on the former and is in contact with the former, which will result in bad cooling of the superconductor tape of that layer. In general, the perpendicular flux density at the edge of the winding is more than the parallel flux density. Superconductor would reduce the current carrying capacity and increase the A.C. losses, if such perpendicular flux density is penetrating the broader surface of the tape. Because of the above two reasons, the first layer and the successive layer of the winding is subjected to high thermal stress. Therefore, there is a need to improve the current carrying capability and cooling of the first layer facing the former and the other layers, and hence corrugated type of former or a grooved type of former is made which is more cumbersome and difficult to make and construct the winding. This invention would ease the cooling of the first layer of the HTS coil and so on by the disclosed arrangement.


Normally, the edge turns of the coil are subjected to perpendicular / radial flux penetration through the broad surface of the superconducting tape.
OBJECTS OF INVENTION:
An object of the invention is to provide a top and bottom winding of the first layer in a solenoidal winding of the HTS coil is reduced by a certain percentage of height of the largest height of the layer of that particular HTS coil (step 1).
Another object of the invention is to provide a top and bottom of the successive layers in a solenoidal winding of the HTS coil is reduced by a certain percentage of height, which is less than the largest height of the layer of that particular HTS coil and upto the largest height of the layer of that HTS coil (step 2).
Another object of the invention is to provide at least the first layer in a solenoid winding of the HTS coil should follow step 1 (step 3).
Another object of the invention is to provide the first layer mentioned in step (1) and step (3) would come immediately next to the former of that particular HTS coil (step 4).
Another object of the invention is to provide no other layer would precede the first layer in a solenoidal winding mentioned in step (1), (3) and (4) of that particular HTS coil


DETAILED DESCRIPTION OF THE INVENTION:
This is a winding arrangement for the reduction of perpendicular flux density that penetrates into the first generation superconducting tape i.e., BISCCO tape and enhances the current capability of the HTS tape, which in turn reduces the ac loss of the winding. The proposed invention is to increase the critical current capacity of the total winding and to reduce the perpendicular flux at the edge turns of the windings and also to improve the cooling of the winding layer next to the former which are otherwise prevented to have adequate cooling on one side of this layer. This results in the HTS coil protected from damage due to hot spot temperature occurs in this particular portion of the winding and the invention of above will ensure safe operation of the HTS coil.
According to the present invention, the top and bottom winding of the first layer in a solenoidal winding of the HTS coil is reduced by a certain percentage of height of the largest height of the layer of that particular HTS coil (step 1).
In accordance to the present invention, the top and bottom of the successive layers in a solenoidal winding of the HTS coil is reduced by a certain percentage of height of the largest height of the layer of that particular HTS coil and upto the largest height of the layer of that HTS coil (step 2).
In accordance to the present invention, at least the first layer in a solenoid winding of the HTS coil needs to follow step 1 (step 3).


In accordance to the present invention, the first layer mentioned in step (1) and step (3) would come immediately next to the former of that particular HTS coil (step 4).
In accordance to the present invention, no other layer would precede the first layer in a solenoidal winding mentioned in step (1), (3) and (4) of that particular HTS coil.