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 INVENTION
An integrated winding system for superconductor transformer
APPLICANTS
Crompton Greaves Limited, CG House, Dr Annie Besant Road, Worli, Mumbai 400 030, Maharashtra, India, an Indian Company
Ramakichenan Vaithiyanathan and Arun Dattatraya Yargole, of Product Technology Centre, CG Global R&D Centre, Crompton Greaves Limited, Kanjur (E), Mumbai 400042, Maharashtra, India, both Indian Nationals
PREAMBLE TO THE DESCRIPTION
The following specification describes the invention


The invention relates to an integrated winding system for superconductor transformer.
In principle, transformer windings are subjected to radial and axial forces under short circuit condition. When transformer windings are made of superconductor tape, then the forces may damage the superconductor winding when adequate mechanical support is not provided. The prior arts US5107240 discloses coils that are secured to tank for withstanding radial forces thereby avoiding quenching deviation is in terms of (i) Ridges with axially-extending channel instead of perforations on former for cooling transformer Another prior arts WO 1995024048 discloses the structural support to react all electromagnetic forces with cooling of coils Deviation is in terms of (i) Focus is on self support superconducting magnetic energy storage (SMES) system. The prior art Patent US7193825 discloses a superconductor fault limiting device with two AC coils surrounding the first arm and second arm. However, there is no disclosure of either material of the AC coil or the aspect relating to reduction of magnetic flux.
In the proposed invention. The advantages of sharing current by two windings under short circuit or fault condition thus providing reduced magnitude of force to the superconductor winding. Thus the superconductor winding is subjected to very less electromagnetic force which it could support without exceeding its limit during the short circuit condition of transformer. Hence the sufficient mechanical strength is ensured for superconductor winding during the dynamic operating condition.
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It is an object of the invention to provide a copper winding connected in series with superconductor winding.
It is an object of the invention to provide a shorting link made of superconductor across the copper winding.
It is an object of the invention to provide a copper winding to be located on the inner surface of the inner winding and outer surface of the outer winding.
The integrated winding systems consist of superconductor and copper winding in series and are placed adjacent to each other. A shorting link made of superconductor winding of suitable design is connected across the copper winding. Under normal operating condition only superconductor winding will be active and copper winding will be inactive. This is done by providing a shorting link made of superconductors which are connected across the copper winding. Under normal condition, the current will pass into the superconductor winding via shorting link connected at the neutral end of the winding. Under short circuit condition, the impedance of the shorting link increases and provide a path for current into the copper winding. Therefore under short circuit condition, both superconductor winding and copper winding is in series and reduce the effective impedance of the coil and hence the current and therefore the short circuit force decreases. In this arrangement, the high low gap under fault condition increases which increases the short circuit impedance and decrease magnitude of the short circuit current further. These two winding reduce the magnitude of the current under short circuit or
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fault condition of transformer and hence the magnitude of the force acting on the two winding will be less than the single winding made of superconductor. The major benefit in this invention is that the requirement of superconductor tape is halved and the superconductor winding is protected from huge mechanical force during the dynamic condition of transformer.
The invention is described in detail herein, a partial cross-sectional view of the winding assembly of a superconducting transformer which consists of a superconductor winding in series with a copper winding and a shorting link made of superconductor is connected across the copper winding. The copper winding is placed on the outer surface of the high and low voltage superconductor winding. The shorting link act as a open circuit under short circuit condition and the large current will flow through the copper winding. The copper winding will limit the short circuit current due to its reactance in series the main winding made of superconductor. Therefore the short circuit current and force on the superconductor winding tape is limited and therefore the protected the superconductor winding against mechanical damage under fault condition or short circuit condition of transformer. In addition to that one halve of the requirement of superconductor tape length is saved due to this arrangement according to an embodiment of the invention. The winding assembly comprises a plurality of layers of inner winding and a plurality of layers of outer winding made of superconducting material wire that are wound on non¬magnetic material inner winding and outer winding formers. A copper windings are connected in series with inner superconductor winding and outer superconductor winding respectively. The copper winding is located before the inner superconductor winding and
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the copper winding is located after the outer superconductor winding. A shorting link made of superconductor material is connected across the copper windings
In accordance to the present invention an integrated winding system for superconductor transformer comprises a copper winding connected in series with the superconductor winding and the said copper winding is located at the inner surface of the inner superconductor winding and the outer surface of the outer superconductor winding and a shorting link is provided across the copper winding and the said link will act as a open circuit during fault condition of the transformer and divert the fault current into the said copper winding. Therefore the fault current is limited by the total impedance of the superconductor and copper winding and protects the superconductor winding from high mechanical force and save half the superconductor material required in the design considering the dynamic operation of transformer.
In accordance to the present invention, said copper winding is connected in series with the superconductor winding to reduce the fault current of the transformer under fault condition.
In accordance to the present invention, said copper winding is placed at the inner surface of the inner superconductor winding and outer surface of the outer winding to increase the radial distance and to increase the short circuit impedance of the transformer under fault condition.
5

In accordance to the
resent invention a shorting link made of superconductor material is connected in parallel with the said copper winding to divert the fault current into the said copper winding.
Dated this 19th day of March 2009

(Ivan Bernard Fuller)
ofKhaitan&Co
Agent for the Applicants
6,