Claims:1. A mechanism for selective addition and subtraction to actuating forces prevailing under different operative conditions of a LV switchgear assembly, the said mechanism comprising at least one main conductor, a first secondary conductor and a second secondary conductor,
wherein a first current is flowed through the first secondary conductor in a first direction and said first current is flowed through the second secondary conductor in a second direction, wherein the first direction and the second direction are opposite to each other, and
wherein the first direction of the first current flowing through the first secondary conductor is similar to that of a direction of a second current flowing through the main conductor to exert a first force necessary to abate a second force, operative in the LV switchgear assembly under an overshoot condition, for a time duration sufficient for the LV switchgear assembly to withstand a transient overshoot in the second current flowing through the main conductor, and
wherein direction of the first current flowing through the first secondary conductor and direction of the first current flowing through the second secondary conductor are reversed to exert a third force to add to the second force, operative in the LV switchgear assembly under the overshoot condition, to open the switchgear assembly to interrupt the second current flowing through the main conductor.
2. A Mechanism for selective addition and subtraction to actuating forces of a LV switchgear assembly, the said mechanism comprising at least one main conductor, a first secondary conductor and a second secondary conductor,
wherein a first current is flowed through the first secondary conductor in a first direction and said first current is flowed through the second secondary conductor in a second direction, wherein the first direction and the second direction are opposite to each other, and
wherein the first direction of the first current flowing through the first secondary conductor is opposite to that of a direction of a second current flowing through the main conductor to exert a first force necessary to abate a second force, operative in the LV switchgear assembly under an overshoot condition, for a time duration sufficient for the LV switchgear assembly to withstand a transient overshoot in the second current flowing through the main conductor, and
wherein direction of the first current flowing through the first secondary conductor and direction of the first current flowing through the second secondary conductor are reversed to exert a third force to add to the second force, operative in the LV switchgear assembly under the overshoot condition, to open the switchgear assembly to interrupt the second current flowing through the main conductor.
3. The mechanism according to any of the preceding claims, wherein the first secondary conductor is shielded, at least in part, by a first magnetic material in a way so that a fourth force exerted by said first magnetic material does not abate any of the first force and the third force.
4. The mechanism according to any of the preceding claims, wherein the second secondary conductor is shielded, at least in part, by a second magnetic material in a way so that a fifth force exerted by said second magnetic material abates any of forces operative when the first current is flowing through the second secondary conductor in the second direction or when direction of the first current flowing through the second secondary conductor is reversed.
5. The mechanism according to any of the preceding claims, wherein the first current flowing through the first secondary conductor and the first current flowing through the second secondary conductor is provided by an auxiliary power source. In another embodiment, the first current flowing through the first secondary conductor and the first current flowing through the second secondary conductor is derived from the main conductor.
6. The mechanism according to any of the preceding claims, wherein direction of the first current flowing through the first secondary conductor and the second secondary conductor is reversed by Dual Pole Double Throw (DPDT) relays. , Description:TECHNICAL FIELD
The disclosure generally relates to the field of power distribution systems. In particular, it pertains to provision of mechanism for achieving selective co-ordination in LV switchgears at user’s discretion.

BACKGROUND
Background description includes information that may be useful in understanding the present invention. It is not an admission that any of the information provided herein is prior art or relevant to the presently claimed invention, or that any publication specifically or implicitly referenced is prior art.
In general, every electrical power supply system must be protected against short circuit conditions and other faulty conditions that may harm the system. In industry, in particular for electrical installations or machines, this protection is achieved by protective devices in the form of fuses or circuit breakers or other overload protection devices which are opened via appropriate tripping units during a short circuit condition.
In use, circuit breakers are subjected to faults which they are not intended to clear. For instance, the design of an electrical system must incorporate the feature that the protective device nearest to the system fault clears the fault without affecting the protective devices that are upstream from it. The purpose of this discrimination is to disconnect only the faulty load or feeder from the network, while keeping as much as possible of the installation powered up. While these faults are not cleared from the system, the breaker needs to withstand the thermal and mechanical stress imposed by the fault current. In the advent of a short circuit, the circuit breaker interrupts the current flow by opening the current carrying contacts. During opening of current carrying contacts in a circuit breaker, non-continuous current flows between the contacts resulting in electrical breakdown of gas (es) which produces an ongoing plasma discharge or electrical arc. In case of absence of suitable means to subside and extinguish the arc produced between current carrying contacts, it can permanently damage the current carrying contacts and hence, the usability of circuit breaker. One of a determinant factor contributing to the arc production and its sustainability between current carrying contacts is the rate of opening of current carrying contacts. Significant research has been done in this technology area to shorten the time taken to open the current carrying contacts.
PCT publication number WO1986006534A1 discloses a system where an electrical coil is provided to flip the magnetic polarity so as to reverse the force developed.
US patent number 3,550,049 discloses a system where the current passing through the closed contacts is divided into two parallel branches so as to produce an electrodynamic force which tends to increase the pressure of the closed contacts and the swinging movement of the contacts destroys this compensating force and in turn opens the contacts.
US patent number 8,674,793 discloses a system where compensation is performed by means of the electrodynamic attraction effect due to flow of the current taking place in the same direction in the two contact elements. However, the disclosure does not provide for reversing the direction of force as required for circuit interruption.
US patent number 7,081,596 and PCT publication number WO2002054431A1 disclose intensifying the current limiting action of the circuit breaker by increasing the magnetic blowout of arc and automatic current limiting features respectively.
Although, several methods and systems disclosed in the prior-art have succeeded, at least in part, in shortening the time taken to open the current carrying contacts, such systems and methods fail to simultaneously provide means effective to withstand the transient overshoot in the current at the user’s discretion. Essentially, such circuit breakers and/or switchgears open the current carrying contacts whenever the flowing current exceeds a threshold current necessitating the manual/semi-automatic/automatic closing of circuits every time the MCB trips. There is therefore a need in the art for improved switchgears/circuit breakers and means and methods that can enable switchgears to withstand transient overshoot current without necessitating them to withstand undue thermal and mechanical stresses arising from faulty conditions for longer duration that can damage such devices.

OBJECTS OF THE INVENTION
An object of the present disclosure is to overcome disadvantages associated with conventional switchgears and circuit breakers.
Another object of the present disclosure is to provide a mechanism for the circuit breakers and switchgear assemblies to enable them to withstand transient overshoot currents.
Another object of the present disclosure is to provide a mechanism for the circuit breakers and switchgear assemblies that can quickly open the current carrying contacts.
Another object of the present disclosure is to provide a mechanism for the circuit breakers and switchgear assemblies that is economical to produce and finds practical utility.

SUMMARY
Aspects of present disclosure relate to LV switchgear devices. In an aspect, the disclosure provides means to overcome deficiencies of the conventional switchgears wherein, the switchgear can withstand the transient overshoot current and can quickly open the current carrying contacts to achieve selective co-ordination with upstream and/or downstream protective devices at user’s discretion.
In an aspect, the present disclosure provides a mechanism for selective addition and subtraction to actuating forces of a LV switchgear assembly, the mechanism including at least a main conductor, a first secondary conductor and a second secondary conductor,
wherein a first current is flowed through the first secondary conductor in a first direction and said first current is flowed through the second secondary conductor in a second direction, wherein the first direction and the second direction are opposite to each other, and
wherein the first direction of the first current flowing through the first secondary conductor is similar to that of a direction of a second current flowing through the main conductor to exert a first force necessary to abate a second force, operative in the LV switchgear assembly under an overshoot condition, for a time duration sufficient for the LV switchgear assembly to withstand a transient overshoot in the second current flowing through the main conductor, and
wherein direction of the first current flowing through the first secondary conductor and direction of the first current flowing through the second secondary conductor are reversed to exert a third force to add to the second force, operative in the LV switchgear assembly under the overshoot condition, to open the switchgear assembly to interrupt the second current flowing through the main conductor.
In an aspect, the present disclosure provides a mechanism for selective addition and subtraction to actuating forces of a LV switchgear assembly, the mechanism including at least a main conductor, a first secondary conductor and a second secondary conductor,
wherein a first current is flowed through the first secondary conductor in a first direction and said first current is flowed through the second secondary conductor in a second direction, wherein the first direction and the second direction are opposite to each other, and
wherein the first direction of the first current flowing through the first secondary conductor is opposite to that of a direction of a second current flowing through the main conductor to exert a first force necessary to abate a second force, operative in the LV switchgear assembly under an overshoot condition, for a time duration sufficient for the LV switchgear assembly to withstand a transient overshoot in the second current flowing through the main conductor, and
wherein direction of the first current flowing through the first secondary conductor and direction of the first current flowing through the second secondary conductor are reversed to exert a third force to add to the second force, operative in the LV switchgear assembly under the overshoot condition, to open the switchgear assembly to interrupt the second current flowing through the main conductor.
In an embodiment, the first secondary conductor is shielded, at least in part, by a first magnetic material in a way so that a fourth force exerted by said first magnetic material does not abate any of the first force and the third force.
In an embodiment, the second secondary conductor is shielded, at least in part, by a second magnetic material in a way so that a fifth force exerted by said second magnetic material abates any of forces operative when the first current is flowing through the second secondary conductor in the second direction or when direction of the first current flowing through the second secondary conductor is reversed.
In an embodiment, the first current flowing through the first secondary conductor and the first current flowing through the second secondary conductor is provided by an auxiliary power source. In another embodiment, the first current flowing through the first secondary conductor and the first current flowing through the second secondary conductor is derived from the main conductor.
In an embodiment, direction of the first current flowing through the first secondary conductor and the second secondary conductor is reversed by Dual Pole Double Throw (DPDT) relays.
Various objects, features, aspects and advantages of the inventive subject matter will become more apparent from the following detailed description of preferred embodiments, along with the accompanying drawing figures in which like numerals represent like components.

BRIEF DESCRIPTION OF THE DRAWINGS
The accompanying drawings are included to provide a further understanding of the present disclosure, and are incorporated in and constitute a part of this specification. The drawings illustrate exemplary embodiments of the present disclosure and, together with the description, serve to explain the principles of the present disclosure.
FIG. 1 illustrates an exemplary diagram of positioning of magnetic materials and secondary conductors or coils in attraction mode in accordance with embodiments to the present disclosure.
FIG. 2 illustrates an exemplary diagram of positioning of magnetic materials and secondary conductors or coils in repulsion mode in accordance with embodiments to the present disclosure.

DETAILED DESCRIPTION
The following is a detailed description of embodiments of the disclosure depicted in the accompanying drawings. The embodiments are in such detail as to clearly communicate the disclosure. However, the amount of detail offered is not intended to limit the anticipated variations of embodiments; on the contrary, the intention is to cover all modifications, equivalents, and alternatives falling within the spirit and scope of the present disclosure as defined by the appended claims.
Each of the appended claims defines a separate invention, which for infringement purposes is recognized as including equivalents to the various elements or limitations specified in the claims. Depending on the context, all references below to the “invention” may in some cases refer to certain specific embodiments only. In other cases it will be recognized that references to the “invention” will refer to subject matter recited in one or more, but not necessarily all, of the claims.
As used in the description herein and throughout the claims that follow, the meaning of “a,” “an,” and “the” includes plural reference unless the context clearly dictates otherwise. Also, as used in the description herein, the meaning of “in” includes “in” and “on” unless the context clearly dictates otherwise.
All methods described herein can be performed in any suitable order unless otherwise indicated herein or otherwise clearly contradicted by context. The use of any and all examples, or exemplary language (e.g. “such as”) provided with respect to certain embodiments herein is intended merely to better illuminate the invention and does not pose a limitation on the scope of the invention otherwise claimed. No language in the specification should be construed as indicating any non-claimed element essential to the practice of the invention.
Various terms as used herein are shown below. To the extent a term used in a claim is not defined below, it should be given the broadest definition persons in the pertinent art have given that term as reflected in printed publications and issued patents at the time of filing.
Aspects of present disclosure relate to LV switchgear devices. In an aspect, the disclosure provides mechanisms to overcome deficiencies of the conventional switchgears wherein, the switchgear can withstand the transient overshoot current and can quickly open the current carrying contacts to achieve selective co-ordination with upstream and/or downstream protective devices at user’s discretion.
In an aspect, the present disclosure provides a mechanism for selective addition and subtraction to actuating forces of a LV switchgear assembly, the mechanism including at least a main conductor, a first secondary conductor and a second secondary conductor,
wherein a first current is flowed through the first secondary conductor in a first direction and said first current is flowed through the second secondary conductor in a second direction, wherein the first direction and the second direction are opposite to each other, and
wherein the first direction of the first current flowing through the first secondary conductor is similar to that of a direction of a second current flowing through the main conductor to exert a first force necessary to abate a second force, operative in the LV switchgear assembly under an overshoot condition, for a time duration sufficient for the LV switchgear assembly to withstand a transient overshoot in the second current flowing through the main conductor, and
wherein direction of the first current flowing through the first secondary conductor and direction of the first current flowing through the second secondary conductor are reversed to exert a third force to add to the second force, operative in the LV switchgear assembly under the overshoot condition, to open the switchgear assembly to interrupt the second current flowing through the main conductor.
In an aspect, the present disclosure provides a mechanism for selective addition and subtraction to actuating forces of a LV switchgear assembly, the mechanism including at least a main conductor, a first secondary conductor and a second secondary conductor,
wherein a first current is flowed through the first secondary conductor in a first direction and said first current is flowed through the second secondary conductor in a second direction, wherein the first direction and the second direction are opposite to each other, and
wherein the first direction of the first current flowing through the first secondary conductor is opposite to that of a direction of a second current flowing through the main conductor to exert a first force necessary to abate a second force, operative in the LV switchgear assembly under an overshoot condition, for a time duration sufficient for the LV switchgear assembly to withstand a transient overshoot in the second current flowing through the main conductor, and
wherein direction of the first current flowing through the first secondary conductor and direction of the first current flowing through the second secondary conductor are reversed to exert a third force to add to the second force, operative in the LV switchgear assembly under the overshoot condition, to open the switchgear assembly to interrupt the second current flowing through the main conductor.
In an embodiment, the first secondary conductor is shielded, at least in part, by a first magnetic material in a way so that a fourth force exerted by said first magnetic material does not abate any of the first force and the third force. In another embodiment, the second secondary conductor is shielded, at least in part, by a second magnetic material in a way so that a fifth force exerted by said second magnetic material abates any of forces operative when the first current is flowing through the second secondary conductor in the second direction or when direction of the first current flowing through the second secondary conductor is reversed.
In an embodiment, the first current flowing through the first secondary conductor and the first current flowing through the second secondary conductor is provided by an auxiliary power source. In another embodiment, the first current flowing through the first secondary conductor and the first current flowing through the second secondary conductor is derived from the main conductor.
In an embodiment, direction of the first current flowing through the first secondary conductor and the second secondary conductor is reversed by Dual Pole Double Throw (DPDT) relays.
In accordance with embodiments of the present invention, any conventional LV switchgear assembly known to a person skilled in the art including but not limited to switchgear assemblies operating through electromagnetic and/or magnetic forces to open and/or close the circuit, switchgear assemblies operating through electromechanical forces to open and/or close the circuit and the like can be provided with the advantageous mechanism, realized in accordance with embodiments of the present disclosure, for selective addition and subtraction to actuation forces prevailing under different operative conditions of the LV switchgear assembly to achieve selective co-ordination with upstream and/or downstream protective devices at user’s discretion.
Essentially, when the current flowing through the switchgear assembly is below a defined threshold, the circuit (i.e. the stationary and the moving current carrying contacts) is maintained in the closed condition under the influence of any of the magnetic forces, electromagnetic forces, mechanical forces and the like so as to allow uninterrupted flow of current through the switchgear assembly. However, when the current flowing through the switchgear assembly exceeds the defined threshold value, large repulsive or attractive forces are generated, depending on the configuration of the switchgear assembly, to break the circuit (i.e. the stationary and the moving current carrying contacts are opened). Hence, in case of transient overshoot, the switchgear trips, breaking the circuit. It necessitates manual/semi-automatic closing of the circuit to allow uninterrupted flow of current. The present invention is based on the principle and an experimentally established phenomenon that like currents attracts and unlike currents repel. If current is flowing in two parallel conductors in same direction, their magnetic fields interact in such a manner so as to produce a resultant attractive force. Conversely, if the current flows in opposite direction, a net repulsive force is obtained. The Ampere force law gives an expression of the force developed due to magnetic field interaction between the conductors. If we consider two long straight parallel wires separated by a distance d carrying currents I1 and I2, force developed per unit length of wire can be obtained by the equation:
F = μI1I2/2πd
This concept can be applied to generate an attractive force to withstand transient overshoot condition at user’s discretion and to generate repulsive forces to quickly open the electrical contacts. For switchgear assemblies where large repulsive forces are generated to quickly open the electrical contacts, the concept can be applied to generate an attractive force to withstand transient overshoot condition at user’s discretion and to generate repulsive forces to quickly open the electrical contacts. Figure 1 illustrates an exemplary 2d model depicting the generation of attractive forces and Figure 2 illustrates an exemplary 2d model depicting the generation of repulsive forces. In accordance with an embodiment of the present invention, the magnetic material 3 encompasses, at least in part, the secondary conductors or coils as illustrated in Figure 1 and Figure 2. The dot and cross are popular sign convention denoting the current flow direction.
As illustrated in Figure 1, in attraction mode, the magnetic material 150 shields the magnetic flux produced by secondary conductor 130 where the current is flowing in opposite direction to main conductor 110 whereas the conductors having current in same direction i.e. main conductor 110 and secondary conductor 120 are exposed to each other thereby resulting in net attractive force due to magnetic flux interaction between the like currents. The flux linkage between the main conductor and the magnetic materials also contribute to the attractive force amplifying the net attractive forces.
As illustrated in Figure 2, in repulsion mode, the current direction in secondary conductors or coils is reversed and the magnetic material 150 shields the magnetic flux produced by the secondary conductor 130 where the current is flowing in same direction to main conductor 110 whereas the conductors having current in opposite direction i.e. main conductor 110 and secondary conductor 120 are exposed to each other thereby resulting in net repulsive force due to magnetic flux interaction between unlike currents. The flux linkage between the main conductor and the magnetic materials reduces the net repulsive force.
The transition from attraction to repulsion mode or vice versa can be achieved by selectively changing the direction of current in secondary conductors or coils. In an embodiment, a solid state switch (e.g. DPDT relay) can be utilized to reverse the direction of current flowing through the secondary conductors. However, it should be appreciated that any other current direction reversing means known to a person skilled in the art can be utilized to serve its intended purpose.
While the foregoing describes various embodiments of the invention, other and further embodiments of the invention may be devised without departing from the basic scope thereof. The scope of the invention is determined by the claims that follow. The invention is not limited to the described embodiments, versions or examples, which are included to enable a person having ordinary skill in the art to make and use the invention when combined with information and knowledge available to the person having ordinary skill in the art.

ADVANTAGES OF THE INVENTION
The disclosure provides a mechanism for switchgears and circuit breakers to overcome disadvantages associated with conventional switchgears and circuit breakers.
The disclosure provides a mechanism for the circuit breakers and switchgear assemblies to enable them to withstand transient overshoot currents.
The disclosure provides a mechanism for the circuit breakers and switchgear assemblies that can quickly open the current carrying contacts.
The disclosure provides a mechanism for the circuit breakers and switchgear assemblies that is economical to produce and finds practical utility.