FORM 2
THE PATENTS ACT, 1970
(39 of 1970)
As amended by the Patents (Amendment) Act, 2005
AND
The Patents Rules, 2003
As amended by the Patents (Amendment) Rules, 2005
COMPLETE SPECIFICATION
(See section 10 and rule 13)
TITLE OF THE INVENTION
An extended electronic system and device for automated calibration of point-of-wave switching controllers for circuit breakers.
APPLICANTS :
Crompton Greaves Limited, CG House, Dr Annie Besant Road, Worli, Mumbai 400 030, Maharashtra, India, an Indian Company
INVENTOR (S):
Namjoshi Yogendra of Crompton Greaves Ltd, CG Global R&D Center, Crompton Greaves Limited, Kanjur Marg, Mumbai 400 042, Maharashtra, India; an Indian National.
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 electrical and electronic equipment.
Particularly, this invention relates to the field of switchgear equipment and controllers, thereof.
More particularly, this invention relates to the field of circuit breakers, its controllers, and associated devices, thereof.
Still more particularly, this invention relates to the field of point-of-wave switching controllers for circuit breakers.
Specifically, this invention relates to an extended electronic system and device for automated calibration of point-of-wave switching controllers for circuit breakers.
BACKGROUND OF THE INVENTION:
The term switchgear, used in association with the electric power system, or substation or power grid, or power distribution systems, refers to the combination of electrical disconnects, fuses and/or circuit breakers used to isolate electrical equipment. Switchgear is used both to de-energize equipment to allow work to be done and to clear faults downstream. Switchgear are also typically employed to protect the associated system against abnormal conditions, such as power line fault conditions or irregular loading conditions or transients. This type of equipment is important because it is directly linked to the reliability of the electricity supply and the electrical load.

Different types of switchgear exist for different applications. A fault interrupter is one type of switchgear. Fault interrupters are employed to automatically open a power line upon the detection of a fault condition.
Circuit breakers are one type of switchgear component. A circuit breaker is an automatically operated electrical switch designed to protect an electrical circuit from damage caused by overload or short circuit. Its basic function is to interrupt continuity upon detection of a fault condition to immediately discontinue electrical flow. The circuit breaker must react to fault condition; in low-voltage circuit breakers this is usually done within the breaker enclosure. Circuit breakers for large currents or high voltages are usually arranged with pilot devices to sense a , fault current and to operate the trip opening mechanism. The trip coil that releases the latch is usually energized by a separate battery, although some high-voltage circuit breakers are self-contained with current transformers, protection relays, and an internal control power source.
Once a fault is detected, contacts within the circuit breaker must open to interrupt the circuit; some mechanically-stored energy (using something such as springs or compressed air) contained within the breaker is used to separate the contacts. Small circuit breakers may be manually operated; larger units have coils to trip the mechanism, and electric motors to restore energy to the springs.
To switch on/off current in electrical systems, a set of contacts may be used. The contacts may be either in an open position, resulting in the stopping of current flow, or in a closed position that allows current flow. The circuit breaker contacts must carry the load current without excessive heating, and must also withstand the

heat of the arc produced when interrupting (opening) the circuit. Contacts are made of copper or copper alloys, silver alloys, and other highly conductive materials.
A trip coil is a type of solenoid in which the moving armature opens a circuit breaker or other protective device when the coil current exceeds a predetermined value. A closing coil is adapted to shut the circuit breaker completely.
In its working mode, if a power surge occurs in the electrical system, the breaker will trip. This means that a breaker that was in the "on" position will flip to the "off position and shut down the electrical power leading from that breaker. Essentially, a circuit breaker is a safety device. When a circuit breaker is tripped, it may prevent a fire from starting on an overloaded circuit; it can also prevent the destruction of the device that is drawing the electricity.
For circuit breaker operation controllers, are used for their actuation. These controllers may include point-on -wave switching mechanisms. The aim of point-on-wave switching is to minimize switching transients, over-voltages and current surges, thereby reducing the stress on equipment insulation. To achieve this, it requires a control device that receives a random command for circuit breaker operation, and synchronizes it with a reference signal, such that the circuit breaker operates at a specified point-on-wave (POW). This is achieved with the help of an electronic device i.e. controller along with circuit breaker.
The point-on-wave switching is also called as controlled switching or synchronous switching.

According to the circuit breakers of the prior art, the point-on-wave switching controllers for circuit breakers need to be calibrated for various compensations in factory and on-site. This means that a dual calibration is required. This required human intervention and equipment at both placed. Calibration parameters include, but are not limited to, the following parameters: 1) mechanical switching time parameter (delay) for close coil; 2) mechanical switching time parameter (delay) for trip coil; 3) mechanical delay time for actual tripping and mechanical switching time for actual closing; 4) SF6 pressure parameter; 5) air pressure parameter; 6) grid frequency; and 7) voltage parameters.
Inaccurate point-on-wave switching provides accurate and synchronous working of the circuit breaker.
. Therefore, there is a need for a circuit breaker and associated controller which obviates the limitations of the prior art relating to dual calibration.
OBJECTS OF THE INVENTION:
An object of the invention is to provide calibration of point-of-wave switching parameters of a controller for switching of circuit breaker.
Another object of the invention is to provide automated calibration of point-of-wave switching parameters of a controller for switching of circuit breaker.
Another object of the invention is to provide automated single calibration of point-of-wave switching parameters of a controller for switching of circuit breaker.

Yet another object of the invention is to provide automated calibration of point-of-wave switching parameters of a controller for switching of circuit breaker at accurate co-ordinates after two or more switching operations.
Still another object of the invention is to provide automated calibration of point-of-wave switching parameters of a controller for switching of circuit breaker taking into consideration all the parameters of the controller.
An additional object of the invention is to provide a feedback based automated calibration of point-of-wave switching parameters of a controller for switching of circuit breaker.
Another object of the invention is to provide a feedback based automatic calibration controller for point-on-wave tripping of trip coils of circuit breaker.
Yet another object of the invention is to provide feedback based automatic calibration controller for point-on-wave closing of close coils of circuit breaker
Still another object of the invention is to provide a fail-safe feedback based automatic calibration controller for switching of circuit breaker.
SUMMARY OF THE INVENTION:
According to this invention, there is provided an extended electronic system and device for automated calibration of point-of-wave switching controllers for circuit

breakers,
I. said device comprises:
a. extension unit adapted to acquire waveforms similar to an oscilloscope unit
adapted to receive current and defined test parameter values in order to be
plotted for graphical and numerical comparison to obtain a comparative
analysis data in relation to threshold (defined) parameter values and
feedback (current) parameter values;
b. extension unit further adapted to store concluded parameters relating to
point-of-wave switching controllers;
c. Power supply unit;
d. 3-phase AC supply unit; and
e. DC supply unit;
II. said system comprises:
i. calibration parameters set-up mechanism adapted to set up at least one calibration parameter from a group of calibration parameter values in relation to said circuit breaker operation;
ii. threshold defining means adapted to define threshold parameter values for each of said selected calibration parameters;
iii. actuation means adapted to actuate said circuit breaker through said system and device;
iv. feedback means with inputs associated with each of said calibration parameters selected by said calibration set-up mechanism; and
v. processing means adapted to receive each threshold value for each calibration parameter from said calibration parameters set-up mechanism and said threshold defining means and to receive feedback parameter values at each switching cycle from said feedback means, said processing

means further adapted to process said received inputs in order to obtain optimum calibration parameter values for each of said selected parameters whose feedback is being received during the switching cycles in order to obtain point-on-wave switching of the circuit breaker that is to be calibrated.
Typically, said calibration parameters set-up mechanism includes selection means adapted to select calibration parameters from a group of parameters consisting of mechanical switching time parameter (delay) for close coil; mechanical switching time parameter (delay) for trip coil; mechanical response time parameter to electrical signals; SF6 pressure parameter; air pressure parameter; grid frequency parameter; and voltage parameters.
Typically, said threshold defining means includes determination means adapted to determine threshold parameter values by a human, based on empirical data and mechanical and electrical characteristics of the circuit breaker associated with said system and device.
Typically, said actuation means includes means to actuate said circuit breaker dependent upon said calibrated parameters.
Typically, said actuation means includes means to actuate / operate the circuit breaker through two or more switching operations.
Typically, said feedback means includes means to relay parameter values through a feedback loop to said calibration set-up mechanism.

Typically, said feedback means includes means to deduce changes in parameter values such that it deduces effect of air pressure on on-wave switching (from maximum to lockout minimum) and SF6 pressure through frequent operations keeping the operating coil-voltage the same.
Typically, said processing means includes iterating means adapted to intelligently obtain optimum parameter values of operation for the associated circuit breaker and controller in correlation with point-on-wave switching, iteratively, through two or more switching cycles.
Typically, said processing means includes modification means to provide modification of operating coil-voltage and deduce effect of air pressure on point-on-wave switching (from maximum DC to minimum DC).
Typically, said processing means includes modification means to provide modification of frequency to keeping 3-phase balance waveforms to deduce the effect of frequency on point-on-wave switching.
Typically, said processing means includes curve fitting means adapted to fit a mathematical curve of a pre-defined order of polynomial in order to provide a working formula for the controller of the circuit breaker.
Typically, said processing means includes curve fitting means adapted to obtain a pre-defined order polynomial which is used to obtain a correlation between the on-constants and variables to control the circuit breaker operation for achieving point-

wave switching.
Typically, said system includes a communication means and channel adapted to download the calibration tables (which have calibrated parameter values) and curve to a main controller which operates said circuit breaker.
BRIEF DESCRIPTION OF THE ACCOMPANYING DRAWINGS:
The invention will now be described in relation to the accompanying drawings, in which:
Figure 1 illustrates a schematic of the system.
DETAILED DESCRIPTION OF THE ACCOMPANYING DRAWINGS:
According to this invention, there is provided an extended electronic system and device for automated calibration of point-of-wave switching controllers for circuit breakers.
The device of this invention includes, among other units, the following units: 1) Extension unit (EU); 2) Power supply unit (PSU); 3) 3-phase AC supply unit (AC); and 4) DC supply unit (DC).
The Extension unit is an electronic device that provides accurate time and amplitude measurements of voltage signals over a wide range of frequencies. Hence, each of the current and defined test parameter values can be plotted by means of an oscilloscope and can be graphically and numerically compared to obtain a comparative analysis. The system of this invention is adapted to use the device of this invention, effectively, to achieve automated calibration parameter

values.
Figure 1 illustrates a schematic of the system.
In accordance with an embodiment of this invention, there is provided a calibration parameters set-up mechanism (CSM) adapted to set up at least one calibration parameter from a group of calibration parameters in relation to circuit breaker (CKB) operation. The Calibration parameters include, but are not limited to, the following parameters: 1) mechanical switching time parameter (delay) for close coil; 2) mechanical switching time parameter (delay) for trip coil; 3) mechanical response time to electrical signals; 4) SF6 pressure parameter; 5) air pressure parameter; 6) grid frequency; and 7) voltage parameters.
In accordance with another embodiment of this invention, there is provided a threshold defining means (TDM) adapted to define threshold parameter values for each of the selected calibration parameters. The threshold parameter values may be determined by a human, based on empirical data and the mechanical and electrical characteristics of the circuit breaker associated with the system and device of this invention.
The EU is engaged to obtain various threshold graphs and numerical parameters as a reference for each of the calibration parameters. The EU is further used by the system of this invention to obtain feedback parameters for pitting against the reference graphs and numerical in order to obtain offsets, variations, and the like parameters.

In accordance with yet another embodiment of this invention, there is provided an actuation means (AM) adapted to actuate the circuit breaker through the system and device of this invention. The actuation of the circuit breaker will be dependent upon the calibrated parameters. In order to achieve the calibration, feedback (in terms of feedback operating values) needs to be obtained from pre-determined outputs of the circuit breaker. The actuation means is adapted to actuate / operate the circuit breaker through two or more switching operations.
In accordance with yet another embodiment of this invention, there is provided a feedback means (FM) with inputs associated with each of the calibration parameters that have been selected by the calibration set-up mechanism. The feedback means relays parameter values through a feedback loop to the calibration set-up mechanism. The feedback means deduces changes in parameter values such that it deduces effect of air pressure on on-wave switching (from maximum to lockout minimum) and SF6 pressure through frequent operations keeping the operating coil-voltage the same.
In accordance with still another embodiment of this invention, there is provided a processing means (PM) adapted to receive each threshold value for each calibration parameter from the calibration parameters set-up mechanism and the threshold defining means. Further, it is adapted to receive feedback parameter values at each switching cycle from the feedback means. The processing means is still further adapted to process these inputs in order to obtain optimum calibration parameter values for each of the selected parameters whose feedback is being received during the switching cycles in order to obtain point-on-wave switching of the circuit breaker that is to be calibrated. Iteratively, through two or more

switching cycles, the processing means is able to intelligently obtain optimum parameter values of operation for the associated circuit breaker and controller in correlation with point-on-wave switching.
Thus, the processing means may provide modification of operating coil-voltage and deduce effect of air pressure on point-on-wave switching (from maximum DC to minimum DC). Further, it may modify the frequency to itself keeping 3-phase balance waveforms to deduce the effect of frequency on point-on-wave switching.
In accordance with an additional embodiment of this invention, there is provided a curve fitting means (CFM) adapted to fit a mathematical curve of a pre-defined order of polynomial in order to provide a working formula for the controller of the circuit breaker. Preferably, a 7th order polynomial is used to obtain a correlation between the constants and variables to control the circuit breaker operation for achieving point-on-wave switching.
In accordance with yet an additional embodiment of this invention, there is provided a communication means and channel (CMC) adapted to download the calibration tables (which have calibrated parameter values) and curve to a main controller (MC).
The advantages of the device and system of this invention can be cited as follows:
1. Easy maintenance through extension device.
2. No human error or intervention.
3. Low requirement of skilled labour on-site.

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. An extended electronic system and device for automated calibration of point-of-wave switching controllers for circuit breakers,
I. said device comprises:
a. extension unit adapted to acquire waveforms similar to an
oscilloscope unit adapted to receive current and defined test
parameter values in order to be plotted for graphical and numerical
comparison to obtain a comparative analysis data in relation to
threshold (defined) parameter values and feedback (current)
parameter values;
b. extension unit further adapted to store concluded parameters relating
to point-of-wave switching controllers;
c. Power supply unit;
d. 3-phase AC supply unit; and
e. DC supply unit;
II. said system comprises:
i. calibration parameters set-up mechanism adapted to set up at least one calibration parameter from a group of calibration parameter values in relation to said circuit breaker operation;
ii. threshold defining means adapted to define threshold parameter values for each of said selected calibration parameters;
iii. actuation means adapted to actuate said circuit breaker through said system and device;

iv. feedback means with inputs associated with each of said calibration parameters selected by said calibration set-up mechanism; and
v. processing means adapted to receive each threshold value for each calibration parameter from said calibration parameters set-up mechanism and said threshold defining means and to receive feedback parameter values at each switching cycle from said feedback means, said processing means further adapted to process said received inputs in order to obtain optimum calibration parameter values for each of said selected parameters whose feedback is being received during the switching cycles in order to obtain point-on-wave switching of the circuit breaker that is to be calibrated.
2. An extended electronic system and device as claimed in claim 1 wherein, said calibration parameters set-up mechanism includes selection means adapted to select calibration parameters from a group of parameters consisting of mechanical switching time parameter (delay) for close coil; mechanical switching time parameter (delay) for trip coil; mechanical response time parameter to electrical signals; SF6 pressure parameter; air pressure parameter; grid frequency parameter; and voltage parameters.
3. An extended electronic system and device as claimed in claim 1 wherein, said threshold defining means includes determination means adapted to determine threshold parameter values by a human, based on empirical data and mechanical and electrical characteristics of the circuit breaker associated with said system and device.

4. An extended electronic system and device as claimed in claim 1 wherein, said actuation means includes means to actuate said circuit breaker dependent upon said calibrated parameters.
5. An extended electronic system and device as claimed in claim 1 wherein, said actuation means includes means to actuate / operate the circuit breaker through two or more switching operations.
6. An extended electronic system and device as claimed in claim 1 wherein, said feedback means includes means to relay parameter values through a feedback loop to said calibration set-up mechanism.
7. An extended electronic system and device as claimed in claim 1 wherein, said feedback means includes means to deduce changes in parameter values such that it deduces effect of air pressure on on-wave switching (from maximum to lockout minimum) and SF6 pressure through frequent operations keeping the operating coil-voltage the same.
8. An extended electronic system and device as claimed in claim 1 wherein, said processing means includes iterating means adapted to intelligently obtain optimum parameter values of operation for the associated circuit breaker and controller in correlation with point-on-wave switching, iteratively, through two or more switching cycles.

9. An extended electronic system and device as claimed in claim 1 wherein, said processing means includes modification means to provide modification of operating coil-voltage and deduce effect of air pressure on point-on-wave switching (from maximum DC to minimum DC).
10. An extended electronic system and device as claimed in claim 1 wherein, said processing means includes modification means to provide modification of frequency to keeping 3-phase balance waveforms to deduce the effect of frequency on point-on-wave switching.
11. An extended electronic system and device as claimed in claim 1 wherein, said processing means includes curve fitting means adapted to fit a mathematical curve of a pre-defined order of polynomial in order to provide a working formula for the controller of the circuit breaker.
12. An extended electronic system and device as claimed in claim 1 wherein, said processing means includes curve fitting means adapted to obtain a pre-defined order polynomial which is used to obtain a correlation between the constants and variables to control the circuit breaker operation for achieving point-on-wave switching.
13. An extended electronic system and device as claimed in claim 1 wherein, said system includes a communication means and channel adapted to download the

calibration tables (which have calibrated parameter values) and curve to a main controller which operates said circuit breaker.