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
A controller with configurable redundant coil-voltage supply compensation
APPLICANTS :
Crompton Greaves Limited, CG House, Dr Annie Besant Road, Worli, Mumbai 400 030, Maharashtra, India, an Indian Company
INVENTOR (S):
Namjoshi Yogendra, Pandharkar Anjani and Rajpal Prashant; all of Crompton Greaves Ltd, CG Global R&D Center, Crompton Greaves Limited, Kanjur Marg, Mumbai 400 042, Maharashtra, 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 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 controller system for controlled switching of a circuit breaker.
More specifically, this invention relates to a controller system for controlled switching of a circuit breaker with a double trip and a double close coil.
More specifically, this invention relates to a controller with configurable redundant coil-voltage supply compensation.
BACKGROUND OF THE INVENTION:
The term switchgear, used in association with the electric power system, or substation or power grid, refers to the combination of electrical disconnectors, 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 conditions; 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.
The point-on-wave switching is also called as controlled switching or synchronous switching.
According to 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.
Further still, there have been advancements which take into consideration an auxiliary trip coil which results into controllers for double trip coils. The Controller gives command to a single trip coil and close coil or gives simultaneous commands to a double trip coil mechanism assuming single coil-voltage supply compensation. For achieving point-on-wave switching, according to the prior art, compensation resulting from 1) mechanical switching time parameter; 2) SF6 parameter; and 3) voltage parameters are to be taking into consideration.
In such double trip coils, two independent supply sources may also be used. The values of these supply sources may be different at a particular instant, thereby resulting in aberaant point-on-wave switching, if the controller is not able to deduce the exact compensation calculation parameters. Thus, there may be possible Loss of point-on-wave target under circumstances when main coil-voltage supply ceases, and if auxiliary coil-voltage supply is available in substation which is not equal to previous value of main coil voltage.
Similar aberrations could occur even during close operation resulting in inaccurate point-on-wave switching. Under currently available systems and controllers, monitoring of trip coil supervision does not detect failure of main coil-voltage supply. They assume station power supply to be equal to coil-voltage supply, which might not be a case in many substations.

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 or point-on-wave switching of circuit breaker.
Another object of the invention is to provide controller point-on-wave tripping of trip coils of circuit breaker.
Yet another object of the invention is to provide controiler point-on-wave dosing of close coils of circuit breaker
Still 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 point-on-wave actuation of dual tripping colls of a circuit breaker.
Yet an additional object of the invention is to control point-on-wave actuation of dual close coils of a circuit breaker.
Still 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 prevent loss of point-on-wave switching under circumstances wherein main trip coil-voltage supply ceases, and if auxiliary trip coil-voltage supply available in substation is not equal to previous value of main coil voltage.
Still an additional object of the invention is to prevent loss of point-on-wave closing under circumstances wherein main close coil-voltage supply ceases, and if auxiliary close coil-voltage supply available in substation is not equal to previous value of main coil voltage.
Another object of the invention is to provide a controller with a circuit breaker.
Still another object of the invention is to detect failure of main coil-voltage supply.
An additional object of the invention is to provide controlled switching which is more reliable with redundancy at coil-voltage and coil levels.
Yet an additional object of the invention is to provide a power system with improved stability.
SUMMARY OF THE INVENTION:
According to this invention, there is provided a controller, for a circuit breaker assembly, with configurable redundant coil-voltage supply compensation, said circuit breaker assembly comprising a main trip coil and a main close coil adapted to receive supply from a first supply line and an auxiliary close coil and, an

auxiliary close coil adapted to receive supply from a second supply line, said controller comprises:
a. first supply line sensing means adapted to sense first supply line pre-defined
parameters in order to relay it to said controller;
b. second supply line sensing means adapted to sense second supply line pre
defined parameters in order to relay it to said controller;
c. main trip coil health monitoring means adapted to monitor health of said main
trip coil in order to relay it to said controller;
d. auxiliary trip coil health monitoring means adapted to monitor health of said
auxiliary trip coil in order to relay it to said controller;
e. main trip coil health monitoring means adapted to monitor health of said main
close coil in order to relay it to said controller;
f. auxiliary trip coil health monitoring means adapted to monitor health of said
auxiliary close coil in order to relay it to said controller;
g. selection means adapted to select a trip coil and a close coil from a combination
of said main trip coil and main close coil combination or said auxiliary trip coil
and auxiliary close coil depending upon said main trip coil health and said main
close coil health or said auxiliary trip coil health and said auxiliary close coil
health and further adapted to select supply line depending upon said sensed first
supply line parameters and said senses second supply line parameters;
h. point-on-wave switching module adapted to compute point-on-wave switching parameters with respect to each of said main trip coil, main close coil, first supply line sensed parameters and said auxiliary trip coil, auxiliary close coil, second supply line sensed parameters; and
i. actuation means adapted to actuate said selected main trip coil and said main close coil in relation to computed point-on-wave switching parameters or said

selected auxiliary trip coil and said auxiliary close coil in relation to computed point-on-wave switching parameters.
Typically, said controller 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 includes parameter input means for said point-on-wave switching module, said parameters selected from a group of parameters consisting of mechanical time (idle time) parameter, coil-voltage (main and auxiliary) parameter, SF6-gas-pressure parameter, air-pressure parameter, grid frequency parameter.
Typically, said controller includes sensing command input means adapted to allow user-defined parameters for providing a programmable option to a user to associate parameters in relation to sensing.
Typically, said controller includes actuation command input means adapted to allow user-defined parameters for providing a programmable option to a user to associate parameters in relation to actuation.

BRIEF DESCRIPTION OF THE ACCOMPANYING DRAWINGS:
Figures 1 and 2 illustrate controller means of the prior art.
The invention will now be described in relation to the accompanying drawings, in which:
Figure 3 illustrates a schematic representation of the coils of the circuit breaker assembly;
Figure 4 illustrates a controller means; and
Figure 5 illustrates a flowchart of the working of the controller of the invention.
DETAILED DESCRIPTION OF THE ACCOMPANYING DRAWINGS:
Figure 1 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 2 also illustrates a controller means of the prior art wherein a main trip coil and an auxiliary trip coil are deployed in a circuit breaker assembly. There is provided a main tripping coil (MTC) and an auxiliary tripping coil (ATC) in a circuit breaker assembly. The main tripping coil functions as a normal tripping coil fts actuation is governed by a controffer and ft 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. Hence, 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. l\ senses a load line 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 clos^ coils (CC).
Two supply lines may be used; one for the main trip coil and another for the auxiliary trip coil. For point-on-wave switching computations in relation to supply line parameters need to be incorporated. The controller, of the prior art, is adapted to give command to single trip coil and close coil or to give simultaneous commands to doubly trip coil assuming single coil-voltage supply compensation, which may be erroneous and may result in inaccurate or faulty point-on-wave switching.

According to this invention, there is provided a controller (CMC) with configurable redundant coil-voltage supply compensation.
Figure 3 illustrates a schematic representation of the coils of the circuit breaker assembly in accordance with this invention.
In accordance with an embodiment of this invention, a main trip coil (Tl), an auxiliary trip coil (T2), a main close coil (CI), and an auxiliary close coil (C2) in a circuit breaker assembly. The main trip coil (Tl), and main close coil (CI) are powered by a first coil voltage supply (DC1). The auxiliary trip coil (T2) and the auxiliary trip close coil (C2) are powered by a second coil voltage supply (DC2). For point-on-wave switching, parameters relating to mechanical switching time, SF6 parameters, and voltage parameters need to be considered.
Supply line (DC1, DC2) parameters may differ. Hence, it is necessary to include sensing means for the supply lines. Further, the controller needs to sense the health of each of the trip coils (Tl, T2) and each of the close coils (CI, C2).
In accordance with another embodiment of this invention, there is provided a first supply line sensing means (SMI) adapted to sense first supply line (DC1) predefined parameters in order to relay it to a controller.
In accordance with another embodiment of this invention, there is provided a second supply line sensing means (SM2) adapted to sense second supply line (DC2) pre-defined parameters in order to relay it to a controller.

In accordance with yet another embodiment of this invention, there is provided a main trip coil health monitoring means (TCH1) adapted to monitor health of said main trip coil. The sensed condition is relayed to the controller.
In accordance with yet another embodiment of this invention, there is provided an auxiliary trip coil health monitoring means (TCH2) adapted to monitor health of said auxiliary trip coil. The sensed condition is relayed to the controller.
In accordance with still another embodiment of this invention, there is provided a close trip coil health monitoring means (CCH1) adapted to monitor health of said main close coil. The sensed condition is relayed to the controller.
In accordance with still another embodiment of this invention, there is provided a close trip coil health monitoring means (CCH2) adapted to monitor health of said auxiliary close coil. The sensed condition is relayed to the controller.
In accordance with an additional embodiment of this invention, there is provided a selection means adapted to select a trip coil and a close coil from a combination of said main trip coil and main close coil combination or said auxiliary trip coil and auxiliary close coil depending upon said main trip coil health and said main close coil health or said auxiliary trip coil health and said auxiliary close coil health and further adapted to select supply line depending upon said sensed first supply line parameters and said senses second supply line parameters.
In accordance with yet an additional embodiment of this invention there is provided an actuation means adapted to actuate said selected main trip coil and said main close coil in relation to computed point-on-wave switching parameters or

said selected auxiliary trip coil and said auxiliary close coil in relation to computed point-on-wave switching parameters. Referring to Figure 3 of the accompanying drawings, Dl refers to drive means for main trip coil, D2 refers to drive means for auxiliary trip coil, D3 refers to drive means for main close coil, and D4 refers to drive means for auxiliary close coil.
Controlled switching is achieved by opening the breaker at particular point-on-current wave. The controller of this invention achieves point-on-wave switching on switchgear through compensation on variation of parameters such as mechanical time (idle time), coil-voltage (main and auxiliary), SF6-gas-pressure, air-pressure, grid frequency and adaptively senses error for future switching.
There may be two coil-voltage supplies (DC1, DC2) for exciting coils which initiates the mechanical assembly of the switchgear/circuit breaker. The controller of this invention takes advantage of this redundant [and generally isolated] power supply from substation and also takes into account its compensation as well. The controller also monitors both coil-voltage supplies and can initiate command based on greater coil voltage among both. It monitors coil health through internal hardware and software and provides a programmable option to the substation engineer to detect trip coil health of both coils and intelligently excite only one coil at a time or both simultaneously, as discussed above and as explained in Figure 5 (flowchart) of the accompanying drawings. It also provides a programmable option to the substation engineer to associate above feature with double-close coil as well with redundancy at close-circuitry level as well.
Figure 4 illustrates a controller means (CMC) of the invention. Three-phase grid voltage (GV), three-phase grid current (GC), feedback and digital input (FI, DI),

and analog inputs (Al) are standard inputs. Further, station supply inputs (SSI), and coil voltage supplies (DC1, DC2) from first and second sensing means (SMI, SM2) are provided. Health status (TCH1, TCH2) of each of the trip coils (TCI, TC2) and health status of (CCH1, CCH2) of each of the close coils (CC1, CC2) are received', in relation to the health status of trip coifs, close coifs, and suppfy fines and in relation to user-defined command inputs (CI), actuation signals are given to the trip coil and close coil combination. Computations in relation to point-on-wave switching are performed by a point-on-wave switching module in the controller means.
Thus, the controller intelligently detects coil health and coil-voltage health and provides point-on-wave switching on the both coil assemblies for failure of coil (burning of coil) or failure of station supply. This results in controlled switching which is more reliable with redundancy at coil-voltage and coil levels. Also, power system stability is improved.
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 controller, for a circuit breaker assembly, with configurable redundant coil-voltage supply compensation, said circuit breaker assembly comprising a main trip coil and a main close coil adapted to receive supply from a first supply line and an auxiliary close coil and an auxiliary close coil adapted to receive supply from a second supply line, said controller comprising:
a. first supply line sensing means adapted to sense first supply line pre
defined parameters in order to relay it to said controller;
b. second supply line sensing means adapted to sense second supply line
pre-defined parameters in order to relay it to said controller;
c. main trip coil health monitoring means adapted to monitor health of said
main trip coil in order to relay it to said controller;
d. auxiliary trip coil health monitoring means adapted to monitor health of
said auxiliary trip coil in order to relay it to said controller;
e. main close coil health monitoring means adapted to monitor health of
said main close coil in order to relay it to said controller;
f. auxiliary close coil health monitoring means adapted to monitor health of
said auxiliary close coil in order to relay it to said controller;
g. selection means adapted to select a trip coil and a close coil from a
combination of said main trip coil and main close coil combination or
said auxiliary trip coil and auxiliary close coil depending upon said main
trip coil health and said main close coil health or said auxiliary trip coil
health and said auxiliary close coil health and further adapted to select
supply line depending upon said sensed first supply line parameters and
said senses second supply line parameters;

h. point-on-wave switching module adapted to compute point-on-wave switching parameters with respect to each of said main trip coil, main close coil, first supply line sensed parameters and said auxiliary trip coil, auxiliary close coil, second supply line sensed parameters; and
i. actuation means adapted to actuate said selected main trip coil and said main close coil in relation to computed point-on-wave switching parameters or said selected auxiliary trip coil and said auxiliary close coil in relation to computed point-on-wave switching parameters.
2. A system as claimed in claim 1 wherein, said controller 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.
3. A system as claimed in claim 1 wherein, said controller includes parameter input means for said point-on-wave switching module, said parameters selected from a group of parameters consisting of mechanical time (idle time) parameter, coil-voltage (main and auxiliary) parameter, SF6-gas-pressureparameter, air-pressure parameter, grid frequency parameter.
4. A system as claimed in claim 1 wherein, said controller includes sensing command input means adapted to allow user-defined parameters for providing a programmable option to a user to associate parameters in relation to sensing.

5. A system as claimed in claim 1 wherein, said controller includes actuation command input means adapted to allow user-defined parameters for providing a programmable option to a user to associate parameters in relation to actuation.