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 THE INVENTION
A system for controlling a circuit breaker with double trip coils
APPLICANTS
Crompton Greaves Limited, CG House, Dr Annie Besant Road, Worli, Mumbai 400 030, Maharashtra, India, an Indian Company
INVENTORS
Pandharkar Anjani, Rajpal Prashant, Rao Nayana, Ekram Samsul, Shinde Hemant, Kale Subodh, Potnis Shrikant, Namjoshi Yogendra, Kambli Upendra and Patange Rajiv; all of Crompton Greaves Limited; 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 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 and controllers, thereof.
Specifically, this invention relates to a system for a gas circuit breaker and controller for double trip coil, thereof, for a power system.
BACKGROUND OF THE INVENTION:
The term switchgear, used in association with the electric power system, or sub-station or power grid, 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. This type of equipment is important because it is directly linked to the reliability of the electricity supply and the electrical load.
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.
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.

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.
According to the circuit breakers of the prior art, a controller is used to control the actuation of the trip coil or the actuation of the close coil of the circuit breaker. The controller is adapted to give command to only one trip coil which is the main trip coil. Even if there is an auxiliary trip coil, the control to the auxiliary trip coil is not currently provided by the controller, when need be. Therefore, if main trip coil gets damaged, controlled switching with auxiliary trip coil is not possible instantly. Further, if the controller's connections are shifted to auxiliary trip coil the, reconfiguration of controller is required by taking various trials. To take these various trials substation shut down is required. Hence, instantaneous relief is not possible. Also, if uncontrolled switching with auxiliary trip coil is done, then it may produce transients in power system, which can deteriorate the insulation of breaker as well as load.
Therefore, there is a need for a circuit breaker and associated controller which obviates the limitations of the prior art.

OBJECTS OF THE INVENTION:
An object of the invention is to provide controlled switching of circuit breaker
Another object of the invention is to provide a fail-safe controlled switching of circuit breaker.
An additional object of the invention is to control the actuation of tripping coils of a circuit breaker.
Yet an additional object of the invention is to achieve improved reliability and stability of power system.
Still an additional object of the invention is to provide one configuration of a controller which drives or is suitable for fail-safe mechanism of tripping of circuit breaker with respect to its actuation time.
Another object of the invention is to provide a controller with a circuit breaker which provides redundant assembly for actuating both trip coils, under emergency conditions.
Yet another object of the invention is to provide a circuit breaker and controller which does not produce transients in power system.
Still another object of the invention is to prevent deterioration of the insulation of circuit breaker as well as load.

SUMMARY OF THE INVENTION:
According to this invention, there is provided a system for a circuit breaker with double trip coil and controller for double trip coil, thereof, for a power system, said system comprises:
a. main tripping coil adapted to trip said circuit breaker in cases of tripping
command as sensed by a controller, said main tripping coil being powered by a
supply line;
b. auxiliary tripping coil adapted to trip said circuit breaker in cases of pre
determined tripping command as sensed by a controller, said auxiliary tripping
coil functioning as a backup tripping coil to said main tripping coil, said
auxiliary tripping coil being powered by a supply line;
c. close coil adapted to close said circuit breaker in cases of closing command as
sensed by a controller; and
d. controller means adapted to provide actuation control signals to each of said
main tripping coil, said auxiliary tripping coil along with main tripping coil and
further adapted to provide actuation control signals to said close coil based,
each of said control signals to said main tripping coil, said auxiliary tripping
coil, and said close coil being based on sensed load line parameters, a plurality
of input parameters, user-defined parameters and computational models,
thereby providing a single controller means for actuation of at least one tripping
coil within a defined actuation time, said tripping coil being selected from a
main tripping coil and an auxiliary tripping coil, thereby providing improved
reliability and stability of said power system.
Typically, said system includes health monitoring means adapted to monitor health of said main tripping coil, health of said auxiliary tripping coil.

Typically, said controller means includes input means adapted to receive input parameters selected from a group of input parameters consisting of control signals parameters in relation to closing coils of said circuit breaker assembly, station supply input parameters, analog input parameters, digital input parameters, command input parameters, feedback input parameters, 3-phase grid voltage input parameters and 3-phase grid current input parameters.
Typically, said controller means includes a point-on-wave sensing mechanism adapted to control switching of circuit breaker at a particular computed point on current wave, as monitored by a monitoring means adapted to monitor power frequency current and voltage waveform and further includes calculation means adapted to calculate the point on wave (opening time) according to pre-defined compensation parameters for actuating said main tripping coil.
Typically, said controller means includes a point-on-wave sensing mechanism adapted to control switching of circuit breaker at a particular computed point on current wave, as monitored by a monitoring means adapted to monitor power frequency current and voltage waveform and further includes calculation means adapted to calculate the point on wave (opening time) according to pre-defined compensation parameters for actuating said auxiliary tripping coil.
Typically, said controller means includes a point-on-wave sensing mechanism adapted to control switching of circuit breaker at a particular computed point on voltage signal, as monitored by a monitoring means adapted to monitor power frequency current and voltage waveforms and further includes calculation means adapted to calculate the point on wave (opening time) according to pre-defined compensation parameters for actuating said closing coil.

Typically, said controller means includes time delay means in order to incorporate a pre-defined time delay if required for actuation of said main tripping coil.
Typically, said controller means includes time delay means in order to incorporate a pre-defined time delay if required for actuation of said auxiliary tripping coil.
Typically, said controller means includes time delay means in order to incorporate a pre-defined time delay if required for actuation of said closing coil.
Typically, said system includes six trip switches to actuate main and auxiliary tripping coils.
BRIEF DESCRIPTION OF THE ACCOMPANYING DRAWINGS:
The invention will now be described in relation to the accompanying drawings, in which:
Figure 1 illustrates a system for a circuit breaker with double trip coil and controller for double trip coil, thereof, for a power system;
Figure 2 illustrates a controller means of the prior art;
Figure 3 illustrates a controller means of the current invention; and
Figure 4 illustrates another embodiment of the controller means according to this invention.

DETAILED DESCRIPTION OF THE ACCOMPANYING DRAWINGS:
According to this invention, there is provided a system for a circuit breaker with double trip coil and controller for double trip coil, thereof, for a power system.
Figure 1 illustrates a system for a circuit breaker with double trip coil and controller for double trip coil, thereof, for a power system.
In accordance with an embodiment of this invention, there is provided a main tripping coil (MTC) and an auxiliary tripping coil (ATC) in a circuit breaker assembly (CB). The main tripping coil functions as a normal tripping coil. Its actuation is governed by a controller and it serves to trip the breaker in cases of tripping command as sensed by the controller. The auxiliary tripping coil functions as a backup tripping coil whose actuation is also governed by a controller. Close coil of the circuit breaker is represented by reference alphabets CC.
Figure 2 illustrates a controller means (CM) of the prior art used to control a single tripping coil (TC) and a single close coil (CC). Inputs in the form of 3-phase grid voltage (GV) and 3-phase grid current (GC) are supplied. Further, analog inputs (AI), digital inputs (DI), station supply inputs (SSI), command inputs (CI) by a user and feedback inputs (FI) are provided to the controller so that the computational mechanism of the controller is adapted to take the plurality of input signals into account in order to firstly decide actuation criteria of tripping coil (TC) or close coil (CC) along with time of actuation or time delay in actuation or the like parameters which effect an appropriate working of the circuit breaker assembly.
Figure 3 illustrates a controller means of the current invention.

In accordance with another embodiment of this invention, there is provided a controller means (CM) adapted to provide control signals to each of said main tripping coil (MTC) and said auxiliary tripping coil (ATC) in an independent or a co-dependent fashion. The controller means is further adapted to provide control signals to closing coils (CC) of the circuit breaker assembly (CB). It senses a load line (LL) which is connected to the circuit breaker assembly. Inputs are similar to the inputs of the prior art, said inputs being station supply inputs (SSI), analog inputs (AI), digital inputs (DI), command inputs (CI) by a user, feedback inputs (FI), 3-phase grid voltage (GV) inputs and 3-phase grid current (GC) inputs. The controller means is also adapted to provide control signals for actuation of close coils (CC).
The close coil is driven by close coil drivers (CCD) of the controller. Figure 4 illustrates another embodiment of the controller means according to this invention. Reference alphabets A, B, C refer to trip coils across three phases of a first three phase supply (MTC). Reference alphabets D, E, F refer to auxiliary trip coils across three phases (ATC). Reference alphabets G, H, I refer to close coils across three phases (CC). The main trip coil is driven by main trip coil drivers (MTCD) of the controller. The auxiliary trip coil is driven by main trip coil drivers (MTCD) of the controller. The close coi] is driven by close coil drivers (CCD) of the controller.
The controller is further adapted to include a point-on-wave sensing mechanism adapted to control switching of circuit breaker at particular point on current wave, as monitored. The controller means monitors power frequency current and voltage waveform. When manual tripping command is given to the controller, it calculates the point on wave (opening time) according to pre-defined compensation parameters. Time delay means is incorporated so that certain pre-defined delay is

added if required and contact separation is done at a pre-determined point on power frequency current wave. Since the trip coil timing of both main and auxiliary is same, the configuration of controller is same for both the coils.
The circuit breaker opening time is based on trip coil characteristics and the speed of operating mechanism. In this invention, the trip coil timing of both main and auxiliary trip coil is ensured to be same so that, the configuration of controller will be common for both the coils.
Thus, a single controller of this invention can be used for switching two trip coils with same actuation time.
The use of this invention provides improved reliability and stability of power system. One configuration is suitable for both trip coil timing. Controlled switching is more reliable as this invention includes two trip coils and a controller for working the same.
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 system for a circuit breaker with double trip coil and controller for double trip coil, thereof, for a power system, said system comprising:
a. main tripping coil adapted to trip said circuit breaker in cases of tripping
command as sensed by a controller, said main tripping coil being powered
by a supply line;
b. auxiliary tripping coil adapted to trip said circuit breaker in cases of pre
determined tripping command as sensed by a controller, said auxiliary
tripping coil functioning as a backup tripping coil to said main tripping coil,
said auxiliary tripping coil being powered by a supply line;
c. close coil adapted to close said circuit breaker in cases of closing command
as sensed by a controller; and
d. controller means adapted to provide actuation control signals to each of said
main tripping coil, said auxiliary tripping coil along with main tripping coil
and further adapted to provide actuation control signals to said close coil,
each of said control signals to said main tripping coil, said auxiliary tripping
coil, and said close coil being based on sensed load line parameters, a
plurality of input parameters, user-defined parameters and computational
models, thereby providing a single controller means for actuation of at least
one tripping coil within a defined actuation time, said tripping coil being
selected from a main tripping coil and an auxiliary tripping coil, thereby
providing improved reliability and stability of said power system.
2. A system as claimed in claim 1 wherein, said system includes health monitoring means adapted to monitor health of said main tripping coil, health of said auxiliary tripping coil.

3. A system as claimed in claim 1 wherein, said controller means includes input means adapted to receive input parameters selected from a group of input parameters consisting of control signals parameters in relation to closing coils of said circuit breaker assembly, station supply input parameters, analog input parameters, digital input parameters, command input parameters, feedback input parameters, 3-phase grid voltage input parameters and 3-phase grid current input parameters.
4. A system as claimed in claim 1 wherein, said controller means includes a point-on-wave sensing mechanism adapted to control switching of circuit breaker at a particular computed point on current wave, as monitored by a monitoring means adapted to monitor power frequency current and voltage waveform and further includes calculation means adapted to calculate the point on wave (opening time) according to pre-defined compensation parameters for actuating said main tripping coil.
5. A system as claimed in claim 1 wherein, said controller means includes a point-on-wave sensing mechanism adapted to control switching of circuit breaker at a particular computed point on current wave, as monitored by a monitoring means adapted to monitor power frequency current and voltage waveform and further includes calculation means adapted to calculate the point on wave (opening time) according to pre-defined compensation parameters for actuating said auxiliary tripping coil.
6. A system as claimed in claim 1 wherein, said controller means includes a point-on-wave sensing mechanism adapted to control switching of circuit breaker at a particular computed point on voltage signal, as monitored by a monitoring means adapted to monitor power frequency current and voltage waveforms and

further includes calculation means adapted to calculate the point on wave (opening time) according to pre-defined compensation parameters for actuating said closing coil.
7. A system as claimed in claim 1 wherein, said controller means includes time delay means in order to incorporate a pre-defined time delay if required for actuation of said main tripping coil.
8. A system as claimed in claim 1 wherein, said controller means includes time delay means in order to incorporate a pre-defined time delay if required for actuation of said auxiliary tripping coil.
9. A system as claimed in claim 1 wherein, said controller means includes time delay means in order to incorporate a pre-defined time delay if required for actuation of said closing coil.
10.A system as claimed in claim 1 wherein, said system includes six trip switches to actuate main and auxiliary tripping coils.