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
COMPLETE SPECIFICATION
(See section 10 and rule 13)
TITLE OF INVENTION
Testing tool for testing shunt reactor with auxiliary windings
APPLICANTS :
Crompton Greaves Limited, CG House, Dr Annie Besant Road, Worli, Mumbai 400 030, Maharashtra, India, an Indian Company
INVENTOR (S):
Kumar Santosh Annadurai, Syed Arif Ahammad and Remje Deepak; all of Crompton Greaves Limited, Building No. 3, CG Global R&D Centre, Crompton Greaves Ltd, Kanjur Marg (East), Mumbai - 400042, India; all Indian Nationals
PREAMBLE TO THE DESCRIPTION:
The following specification particularly describes the nature of this invention and the manner in which it is to be performed:

Field of the Invention:
This invention relates to the field of testing systems and transformers.
Particularly, this invention envisages a testing tool for testing shunt reactor with auxiliary windings.
Background of the Invention:
A transformer is a device which transfers energy from once circuit to another. The transformer has a set of coils which perform this function. It is a static equipment. The set of coils are conductors which are inductively coupled. The coils are a set of primary winding coils which are typically connected to a first energy source and a set of secondary winding coils to which the transfer of energy takes place. The windings are wound about a central core.
Some power transformers are immersed in transformer oil that both cools and insulates the windings. The oil may be a highly refined mineral oil that remains stable at transformer operating temperature. The oil provides a dielectric medium and provides capacitance between the core and the transformer housing tank.
A common failure mode for Power Transformers and reactors is consequent to mechanical deformation of core or windings. Core damage is more likely as a result of transportation and winding damage is as a result of short circuit type forces.
Sweep Frequency Response Analysis (SFRA) interpretation guidelines are available of the existing designs of transformers and reactors only. SFRA is an

analysis technique used to assess the mechanical integrity of the Power Transformers, winding displacement and deformation in Power Transformers, during the transportation, installation and post fault conditions.
In recent times, new designs of shunt reactor with auxiliary windings are coming up for rural electrification of small residential habitats in non-accessible areas. Instead of transporting and installing three phase transformer, the existing shunt reactors are modified to be fitted with auxiliary windings (either on the sides, or on top, or on bottom). Shunt reactors may already be installed. Shunt reactors are the most compact and cost-efficient means of compensating capacitive generation in long-transmission high-voltage power lines or extended cable systems. Alternative solutions are more expensive, mean greater losses, require more equipment and demand additional resources.
It is important to check that the core lamination is protected from dielectric stress that can arise from high voltage winding, eliminating the risk of partial discharges on the core surface.
Since this product (shunt reactor with auxiliary winding) is used for locations where transportation is difficult and is prone to damages, it necessitates that the customer assesses the received product at site. Also, since due to the in-born characteristics of lack of high impedance to improve regulation, the winding is prone to short circuit forces which can further cause deformation to the windings. Also, since this product is of new design and new to market, analysis tools and SFRA guidelines are not available for such product. Hence, there are no matching criterion or look-up tables or system for verifying the integrity of the on-site reactor.

Hence there is a need for an interpretation tool and analysis technique for customers as well as OEMs to ensure their product reliability.
SFRA response to find the winding deformation in transformers can be done by comparing the fault response of one phase to another phase with the healthy response. But in a reactor, since it consists of only one winding, the response of this winding can be compared with the auxiliary windings. Hence, it is necessary to provide a tool with SFRA guidelines for shunt reactor with Auxiliary windings.
Objects of the Invention:
An object of the invention is to assess the mechanical integrity of shunt rectors with auxiliary windings.
Another object of the invention is to provide a testing tool to verify reactor integrity and performance criteria.
Summary of the Invention:
According to this invention, there is provided a testing tool for testing shunt reactor having areas including at least a main winding, at least a first auxiliary winding, and at least a second auxiliary winding, said tool comprises:
- input means adapted to receive input from pre-defined areas said shunt reactor, said input being pulses or signals generates at leads of said tool;
- plotting means adapted to plot a Sweep Frequency Response Analysis (SFRA) graph with respect to said received inputs in terms of frequency (F) of said signal and amplitude (dB) of said signal;

- look-up database containing pre-measured parameters of a defined standard shunt reactor with different auxiliary windings, thereby forming multiple look-up tables with values, parameters and shunt reactor areas;
- capturing means adapted to capture peaks and troughs of a plotted SFRA graph at different segmented portions of said graph to obtain captured values;
- comparator means adapted to compare each of said captured values with corresponding values from said look-up tables; and
- notification means adapted to notify the parameter and area from said lookup table where a breach of record in values is found.
Typically, said look-up table includes absolute values adapted to be used by said comparator means.
Typically, said look-up table includes deviation values adapted to be used by said comparator means.
Typically, said predefined areas includes a location selected from a plurality of locations consisting oft least a main winding, at least a first auxiliary winding, and at least a second auxiliary winding and their combinations.
Preferably, said input means includes terminals with means to injects a sinusoidal signal of wide range of frequency 20Hz to 2MHz at one terminal of reactor and measures the response at other terminal.
Preferably, said look-up table includes a reference parameter of 68db magnitude for a healthy condition of said main winding with leads across said main winding.

Preferably, said look-up table includes a reference parameter of 57db magnitude for a shorted condition of said first auxiliary winding with leads across said main winding, thereby resulting in a conclusion that the main winding SFRA response is distorted in mid frequency region due to fault in said first auxiliary winding and said second auxiliary winding.
Preferably, said look-up table includes a reference parameter of 62db magnitude for a shorted condition of said second auxiliary winding with leads across said main winding, thereby resulting in a conclusion that the main winding SFRA response is distorted in mid frequency region due to fault in said first auxiliary winding and said second auxiliary winding.
Preferably, said look-up table includes a reference parameter of 46db magnitude for a healthy condition of said main winding with leads in said main winding,
Preferably, said look-up table includes a reference parameter of 62db magnitude for a shorted condition of 5th and 6th discs of said main winding with leads in said main winding, thereby resulting in a conclusion that the bottom portion of main winding SFRA response is distorted in high frequency region.
Preferably, said look-up table includes a reference parameter of 64db magnitude for a shorted condition of 19th and 21st discs of said main winding with leads in said main winding, thereby resulting in a conclusion that the middle portion of main winding SFRA response is distorted in high frequency region.

Preferably, said look-up table includes a reference parameter of 61db magnitude for a shorted condition of 27th and 29h discs of said main winding with leads in said main winding, thereby resulting in a conclusion that the bottom portion of top winding SFRA response is distorted in high frequency region.
Preferably, said look-up table includes a reference parameter of 23db magnitude for a healthy condition of said first auxiliary winding with leads in said first auxiliary winding.
Preferably, said look-up table includes a reference parameter of 40db magnitude for a shorted condition of said first auxiliary winding with leads in said first auxiliary winding, thereby resulting in a conclusion that the distortion in SFRA response of said first auxiliary winding in mid frequency region is due to fault in said main winding.
Preferably, said look-up table includes a reference parameter of 22db magnitude for a healthy condition of said second auxiliary winding with leads in said second auxiliary winding.
Preferably, said look-up table includes a reference parameter of 31db magnitude for a shorted condition of said second auxiliary winding with leads in said second auxiliary winding, thereby resulting in a conclusion that the distortion in SFRA response of said second auxiliary winding in mid frequency region is due to fault in said main winding.

Preferably, said look-up table includes a reference parameter of 54db magnitude for a healthy condition of placement of said main winding with respect to said first auxiliary winding with leads across said main winding and said first auxiliary winding.
Preferably, said look-up table includes a reference parameter of 40db magnitude for displacement placement of said main winding with respect to said first auxiliary winding due to shorted condition of said second auxiliary winding with leads across said main winding and said first auxiliary winding, thereby resulting in a conclusion that the SFRA response of said main winding and said first auxiliary winding is distorted in mid frequency region due to shorting of said second auxiliary winding.
Preferably, said look-up table includes a reference parameter of 54db magnitude for a healthy condition of placement of said main winding with respect to said second auxiliary winding with leads across said main winding and said second auxiliary winding.
Preferably, said look-up table includes a reference parameter of 40db magnitude for displacement placement of said main winding with respect to said second auxiliary winding due to shorted condition of said first auxiliary winding with leads across said main winding and said second auxiliary winding, thereby resulting in a conclusion that the SFRA response of said main winding said second auxiliary winding is distorted in mid frequency region due to shorting of said first auxiliary winding.

Brief Description of the Accompanying Drawings:
Figure 1 illustrates a schematic view of the transformer with a core and windings; and
Figure 2 illustrates a schematic view of the shunt reactor with auxiliary windings.
The invention will now be described in relation to the accompanying drawings, in which:
Figure 3 illustrates a schematic view of the SFRA in graphical format;
Figure 4 illustrates a schematic of the testing tool; and
Figure 5 to 14 illustrate various exemplary graphs which are representative of the various permutations and combinations of healthy and faulty conditions of the main winding and auxiliary windings of the shunt reactor.
Detailed Description of the Accompanying Drawings:
Figure 1 illustrates a schematic view of the transformer (10) with a core (12) and windings (14).
Figure 2 illustrates a schematic view of the shunt reactor (20) with auxiliary windings (reference numeral 22 represented by A1-A2 or B1-B2). The auxiliary windings (A1-A2 or B1-B2) may be placed on any one of the shown places (i.e. on the top side or on the bottom side or on the lateral edges).

The design of shunt reactors with auxiliary windings have a main winding (H1-H2) on a central limb and auxiliary windings on the upper or bottom portion of the same limb or even on the side limbs based on the impedance and the regulation targeted.
According to this invention, there is provided a testing tool (40) for testing shunt reactor with auxiliary windings.
Figure 4 illustrates a schematic of the testing tool.
In accordance with an embodiment of this invention, there is provided an input means (42) adapted to receive input from pre-defined locations of the system of shunt reactor with auxiliary winding(s). Pulses or signals are generates at the leads and responses are recorded in the form of frequency (F) of the signal and amplitude (dB) of the signal.
Table 1 below depicts Shunt Reactor winding arrangement and Test Conditions:

Sr. No. Type Red Lead Black Lead Connection shorted
1 Open (self test) B R RB
2 Open H1 H2 NA
3 Open A1 A2 NA
4 Open B1 B2 NA
5 Open H1 A1 NA
6 Open H1 Bl NA
7 Short H1 H2 A1,A2,Gnd
8 Short H1 H2 Bl,B2,Gnd
9 Short A1 A2 H1,H2
10 Short B1 B2 H1.H2
11 Short H1 H2 Disk 5,7

12 Short H1 H2 Disk 19,21
13 Short H1 H2 Disk 27,29
Table 1
This method injects a sinusoidal signal of wide range of frequency 20Hz to 2MHz at one terminal of reactor and measures the response at other terminal.
In accordance with another embodiment of this invention, there is provided a plotting means (44) adapted to plot a Sweep Frequency Response Analysis (SFRA) graph with respect to said received inputs.
Figure 3 illustrates a schematic view of the SFRA in graphical format. The graph is plotted with Frequency (F) on the X-axis with respect to Amplitude (dB) on the Y-axis. Preferably, a first half of the graph correlates to the inductance (L1, L2) of the reactor and a second half of the graph correlated to the capacitance (C1, C2) of the reactor. In relation to the prior art SFRA analyses, it has been observed that L1 relates to the core, L2 relates to the leads, C1 relates to the insulation, and C2 relates to the displacement of the windings in the tank.
In accordance with yet another embodiment of this invention, there is provided a look-up database (46) containing pre-measured parameters of a defined shunt reactor with auxiliary windings. The look-up database, typically, has relatively correct parameters of a variety of shunt reactors with different placement of auxiliary windings, thereby forming multiple look-up tables.
In accordance with still another embodiment of this invention, there is provided a capturing means (48) adapted to capture peaks and troughs of the graph at different segmented portions of the graph to obtain captured values. For each captured peak

of the segmented portion of the graph, there is a comparative 'absolute' value in the look-up tables of the look-up database which is the correct value.
In accordance with an additional embodiment of this invention, there is provided a comparator means (50) adapted to compare each of captured values with the corresponding values from the look-up tables.
In accordance with yet an additional embodiment of this invention, there is provided a notification means (52) adapted to notify the parameter and area from the look-up table where a breach of record in values is found.
SFRA measurements have been carried out on 3 ratings of shunt reactors of healthy and later deformed condition and their commonality is derived to frame the guidelines for the interpretation.
Tests are envisaged to obtain a range of values for each component of the shunt reactor with auxiliary windings. These ranges of values will be the absolute values. Deviation tolerances will be fed in the look-up tables. These will serve as the basis for comparison.
Since this product (shunt reactor with auxiliary winding) is used for locations where transportation is difficult and is prone to damages, it necessitates that the customer assesses the received product at site. Also, since due to the in-born characteristics of lack of high impedance to improve regulation, the winding is prone to short circuit forces which can further cause deformation to the windings. Hence this interpretation tool is necessary for customers as well as OEMs to ensure their product reliability.

According to a non-limiting exemplary embodiment, a shunt reactor with auxiliary winding was taken. A self response test was carried out to ensure calibration parameters of the tool of this invention. The graph, as illustrated in Figure 5of the accompanying drawings, is a self response test graph and the nature of the curve, visible therein, ensures that the calibration of the testing tool was okay and ensured that the test leads and instrument performance were healthy.
According to another non-limiting exemplary embodiment, the testing tool was used on a plurality of shunt reactors with auxiliary windings and main windings with varied status of health conditions of the main windings and auxiliary windings according to various permutations and combinations in order to draw illustrative curves for the SFRA guidelines. Recurrence of such curves on other shunt reactors with auxiliary windings and main windings, using the tool of this invention, shall enable a user to identify and pinpoint pain points or fault areas in the shunt reactor.
Figure 6, of the accompanying drawings, illustrates the SFRA response of the HV (main) winding for a healthy condition, i.e. without fault. The portion of the curve marked, 'healthy', represents that the main winding is in a healthy state of being.
Figure 7, of the accompanying drawings, illustrates the SFRA response of the HV (main) winding (H1H2) with a first short auxiliary winding (A1A2) and a second ground auxiliary winding (B1B2). If fault occurs in the auxiliary winding, that is when the LV windings 1 and 2 are shorted, and then the SFRA response of HV winding is compared with that of a healthy one. The portion of the curve marked, 'healthy', represents that the main winding is in a healthy state of being. The

portion of the curve marked, 'faulty condition in A1A2', represents that the first auxiliary winding is in a faulty state of being. The portion of the curve marked, 'faulty condition in B1A2', represents that the first auxiliary winding is in a faulty state of being.
Figure 8, of the accompanying drawings, illustrates the SFRA response of the first auxiliary winding (A1A2) with the main winding (H1H2) shorted. The graph shows the SFRA response of the first auxiliary winding when the main winding is shorted and the response is compared with that of healthy response. NF represents No Fault condition. SH represents Short condition.
Figure 9, of the accompanying drawings, illustrates the SFRA response of the second auxiliary winding (B1B2) with the main winding (H1H2) shorted. The graph shows the SFRA response of the second auxiliary winding when the main winding is shorted and the response is compared with that of healthy response. NF represents No Fault condition. SH represents Short condition.
Figure 10, of the accompanying drawings, illustrates the SFRA response of the main winding with bottom interdisc shorted. The graph illustrates the SFRA response of the main winding of 'healthy' and 'faulty' condition when 5th, 7th discs are shorted and compared. NF represents No Fault condition. SH represents Short condition.
Figure 11, of the accompanying drawings, illustrates the SFRA response of the main winding with middle interdisc shorted. The graph illustrates the SFRA response of the main winding of 'healthy' and 'faulty' condition when 19th, 21st

discs are shorted and compared. NF represents No Fault condition. SH represents Short condition.
Figure 12, of the accompanying drawings, illustrates the SFRA response of the main winding with top interdisc shorted. The graph illustrates the SFRA response of the main winding of 'healthy' and 'faulty' condition when 27th, 29th discs are shorted and compared. NF represents No Fault condition. SH represents Short condition.
Figure 13, of the accompanying drawings, illustrates the SFRA response of the main winding with respect to the first auxiliary winding when the second auxiliary winding is shorted. The graph illustrates the SFRA response of the main winding at healthy and faulty condition (where second auxiliary winding is shorted) and compared. NF represents No Fault condition. SH represents Short condition.
Figure 14, of the accompanying drawings, illustrates the SFRA response of the main winding with respect to the second auxiliary winding when the first auxiliary winding is shorted. The graph illustrates the SFRA response of the main winding at healthy and faulty condition (where first auxiliary winding is shorted) and compared. NF represents No Fault condition, SH represents Short condition.
The following table, Table 2, illustrates condition status and representative magnitudes in respect of conditions of faults in reference to positioning of test leads at different positions of the shunt reactor (including main windings H1H2, first auxiliary windings A1A2, and second auxiliary windings B1B2).

Different positions of shunt reactor condition Magnitude Shift in magnitude Frequency range conclusion
Across
Main
winding
H1....H2 Healthy condition 68db 30kHz to 100kHz

A1A2 shorted 57db 10db
Main winding SFRA response distorted in mid frequency region

B1B2 shorted 62db 6db
due to fault in first auxiliary winding and second auxiliary winding.
In main winding healthy 46db

5th & 6th
discs
shorted 62db 16db 100kHz to 200kHz Bottom portion of Main winding SFRA response distorted in high frequency region

19th& 21st discs shorted 64db 18db 200kHz to
500kHz Middle portion of Main winding SFRA response distorted in high frequency region

27th & 29th
discs shorted 61db 15db 100kHz to 200kHz Top portion of Main winding SFRA response distorted in high frequency region
First
Auxiliary
winding healthy 23 db 18db 20 kHz to 60 kHz Distortion in SFRA response of first Auxiliary winding i.e. left

(A1A2) HV
shorted 40 db side portion of main winding in mid frequency region due to fault in main winding (H1H2)
Second Auxiliary winding (B1B2) healthy 22 db 9db 50 kHz to 70 kHz. Distortion in SFRA response of second Auxiliary winding i.e. right side portion of main winding in mid frequency region due to fault in main winding(H1H2)

HV
shorted 31 db

Main
winding to first
auxiliary winding HV to LV1 healthy 54 db 14db 40 kHz to 100 kHz. SFRA response of Main winding & first auxiliary winding (LV1) distorted in mid frequency region due to second auxiliary winding (LV 2) shorted

LV2 shorted 40 db

Main
winding to second auxiliary winding HV to LV2 healthy 54 db 14db 30 kHz to 100 kHz. SFRA response of Main winding & second auxiliary winding (LV2) distorted in mid frequency region due to first auxiliary winding (LV1) shorted

LV1 shorted 40 db

While this detailed description has disclosed certain specific embodiments of the present invention for illustrative purposes, various modifications will be apparent to those skilled in the art which do not constitute departures from the spirit and scope of the invention as defined in the following claims, and it is to be distinctly understood that the foregoing descriptive matter is to be interpreted merely as illustrative of the invention and not as a limitation.

We claim,
1. A testing tool for testing shunt reactor having areas including at least a main winding, at least a first auxiliary winding, and at least a second auxiliary winding, said tool comprising:
- input means adapted to receive input from pre-defined areas said shunt reactor, said input being pulses or signals generates at leads of said tool;
- plotting means adapted to plot a Sweep Frequency Response Analysis (SFRA) graph with respect to said received inputs in terms of frequency (F) of said signal and amplitude (dB) of said signal;
- look-up database containing pre-measured parameters of a defined standard shunt reactor with different auxiliary windings, thereby forming multiple look-up tables with values, parameters and shunt reactor areas;
- capturing means adapted to capture peaks and troughs of a plotted SFRA graph at different segmented portions of said graph to obtain captured values;
- comparator means adapted to compare each of said captured values with corresponding values from said look-up tables; and
- notification means adapted to notify the parameter and area from said look-up table where a breach of record in values is found.

2. A testing tool as claimed in claim 1 wherein, said look-up table includes absolute values adapted to be used by said comparator means.
3. A testing tool as claimed in claim 1 wherein, said look-up table includes deviation values adapted to be used by said comparator means.

4. A testing tool as claimed in claim 1 wherein, said predefined areas includes a location selected from a plurality of locations consisting of t least a main winding, at least a first auxiliary winding, and at least a second auxiliary winding and their combinations.
5. A testing tool as claimed in claim 1 wherein, said input means includes terminals with means to injects a sinusoidal signal of wide range of frequency 20Hz to 2MHz at one terminal of reactor and measures the response at other terminal.
6. A tool as claimed in claim 1 wherein, said look-up table includes a reference parameter of 68db magnitude for a healthy condition of said main winding with leads across said main winding.
7. A tool as claimed in claim 1 wherein, said look-up table includes a reference parameter of 57db magnitude for a shorted condition of said first auxiliary winding with leads across said main winding, thereby resulting in a conclusion that the main winding SFRA response is distorted in mid frequency region due to fault in said first auxiliary winding and said second auxiliary winding.
8. A tool as claimed in claim 1 wherein, said look-up table includes a reference parameter of 62db magnitude for a shorted condition of said second auxiliary winding with leads across said main winding, thereby resulting in a conclusion that the main winding SFRA response is distorted in mid

frequency region due to fault in said first auxiliary winding and said second auxiliary winding.
9. A tool as claimed in claim 1 wherein, said look-up table includes a reference
parameter of 46db magnitude for a healthy condition of said main winding
with leads in said main winding.
10.A tool as claimed in claim 1 wherein, said look-up table includes a reference parameter of 62db magnitude for a shorted condition of 5th and 6th discs of said main winding with leads in said main winding, thereby resulting in a conclusion that the bottom portion of main winding SFRA response is distorted in high frequency region.
11 .A tool as claimed in claim 1 wherein, said look-up table includes a reference parameter of 64db magnitude for a shorted condition of 19th and 21st discs of said main winding with leads in said main winding, thereby resulting in a conclusion that the middle portion of main winding SFRA response is distorted in high frequency region.
12.A tool as claimed in claim 1 wherein, said look-up table includes a reference parameter of 61db magnitude for a shorted condition of 27th and 29h discs of said main winding with leads in said main winding, thereby resulting in a conclusion that the bottom portion of top winding SFRA response is distorted in high frequency region.

13.A tool as claimed in claim 1 wherein, said look-up table includes a reference parameter of 23db magnitude for a healthy condition of said first auxiliary winding with leads in said first auxiliary winding.
14.A tool as claimed in claim 1 wherein, said look-up table includes a reference parameter of 40db magnitude for a shorted condition of said first auxiliary winding with leads in said first auxiliary winding, thereby resulting in a conclusion that the distortion in SFRA response of said first auxiliary winding in mid frequency region is due to fault in said main winding.
15.A tool as claimed in claim 1 wherein, said look-up table includes a reference parameter of 22db magnitude for a healthy condition of said second auxiliary winding with leads in said second auxiliary winding.
16. A tool as claimed in claim 1 wherein, said look-up table includes a reference parameter of 31db magnitude for a shorted condition of said second auxiliary winding with leads in said second auxiliary winding, thereby resulting in a conclusion that the distortion in SFRA response of said second auxiliary winding in mid frequency region is due to fault in said main winding.
17.A tool as claimed in claim 1 wherein, said look-up table includes a reference parameter of 54db magnitude for a healthy condition of placement of said main winding with respect to said first auxiliary winding with leads across said main winding and said first auxiliary winding.

18.A tool as claimed in claim 1 wherein, said look-up table includes a reference parameter of 40db magnitude for displacement placement of said main winding with respect to said first auxiliary winding due to shorted condition of said second auxiliary winding with leads across said main winding and said first auxiliary winding, thereby resulting in a conclusion that the SFRA response of said main winding and said first auxiliary winding is distorted in mid frequency region due to shorting of said second auxiliary winding.
19.A tool as claimed in claim 1 wherein, said look-up table includes a reference parameter of 54db magnitude for a healthy condition of placement of said main winding with respect to said second auxiliary winding with leads across said main winding and said second auxiliary winding.
20.A tool as claimed in claim 1 wherein, said look-up table includes a reference parameter of 40db magnitude for displacement placement of said main winding with respect to said second auxiliary winding due to shorted condition of said first auxiliary winding with leads across said main winding and said second auxiliary winding, thereby resulting in a conclusion that the SFRA response of said main winding said second auxiliary winding is distorted in mid frequency region due to shorting of said first auxiliary winding.