FORM 2
THE PATENTS ACT, 1970 (39 of 1970)
COMPLETE SPECIFICATION
(See section 10 and rule 13)
1. TITLE OF THE INVENTION
Condition based impedance current limiter
2. APPLICANT(S)
(a) NAME : Larsen and Toubro Ltd.
(b) NATIONALITY: Indian
(c)ADDRESS : L&T House, Ballard Estate, Mumbai-400 001, India.
3. PREAMBLE TO THE DESCRITION
PROVISIONAL COMPLETE
The following specification describes The following specification particularly describes the
invention invention and the manner in which it is to be performed
4. DESCRIPTION (Description shall start from next page)
5. CLAIMS (not applicable for provisional specification. Claims should start with the preamble -
"I/We claim" on separate page)
6. DATE AND SIGNATURE (to be given on the last page of specification)
7. ABSTRACT OF THE INVENTION (to be given along with complete specification on the separate page)
Note:
*Repeat boxes in case of more than one entry
*To be signed by the applicants)or the authorized registered patent agent
*Name of the applicant should be given in full, family name in the beginning
*Complete address of the applicant should be given stating with postal index no. / code, state and
country
*Strike out the column which is/are not applicable

Condition based impedance current limiter
Field of the invention
The present invention generally relates to current limiting technology and particularly it relates to a condition based impedance current limiting technology at room temperature.
Background of the invention
For a healthy and stabilized power system operation it is necessary to have a balance in the power flow i.e. the total power generated shall be equal to the load demand and system losses. With the increase in the load demand, for constant power loss the generation of the power has to be increased otherwise it may call for a load shedding in the power system and in extreme case will lead to complete shutdown. To cope up with the problem of heavy power demand immediate remedial action is to import power from neighbour regional grid through tie lines. However in case this is not possible than the only option left out is to increase the generation capacity of the individual regional power system. This will increase its fault level. The rating of the associated switchgear devices linked with the infinite bus is supposed to increase. This will lead to three major problem viz. Increase in the installation and running cost, reliability as the power system will be in stall condition for long duration and overall size of the system. To overcome the above problem conventional methodology is to split the local network system into parallel path with fault level suitable for the rated short circuit rating of the switchgear devices. Yet few more methods which limit the fault current by means of inserting few turns of incoming cables at the primary distribution circuit; use of high rupturing delayed & fast acting fuses; Inductive and resistive based fault current limiter using super conductor at cryogenic state. In some cases provision is given in the switching device (MCCB) itself by means of reversing the current carrying path; use of slot motor; suitable geometrical shape of the contact button.
Network plitting and coil with incoming cables will increase the installation cost and size of the system. Similarly the fuse will increase the overall power consumption of the utility and ambient temperature of the panel. Its performance is unreliable as the cut off current and let through energy varies for the same manufacturer. Also it can be used only for single operation. The best solution for this is a superconducting based resistive or inductive type fault current limiter, which operates at cryogenic state (<77K). The problem associated with it is high cost cooling system

and special material such as YBCO and BiSCo for current carrying and shielding action. Due to the requirement of cooling system the overall size of the current limiter increases. Several other techniques were adopted using solid state devipe connected in parallel with lumped parameters such as inductor & capacitor. In this case since the rated current is carried by the solid state switch, which owing to high voltage drop will consume more power. This will lead to high resistive loss between the power terminals and hence high temperature of the solid state switch. To avoid this adequate heat sink (with or without fan cooling) with higher panel size will be needed to regulate the temperature and protect the device. Also due to variation in the ambient temperature, reliability of such devices is always in doubt. For all the above said current limiting technology, in the event of a surge with high di/dt during starting of very high inductive load(such as slip or squirrel cage induction motor) which lasts for few ms to 1 second, the current limiting effect is unable to discriminate a fault with a temporary overload or surge condition. This may lead to complete stall of the equipment and will never allow the device to start. In this present scenario what is required is a conditional based impedance current limiting technology which will discriminate between th£ temporary overload and faulted condition. Also it should be less costly and with low resistive loss.
It is also required to provide low voltage drop, watt loss, minimize temperature rise and cost as compared to solid state switch current limiting technology. Also it demands for an arrangement that does not require special cooling unit to maintain cryogenic temperature and a low cost and size as compared to superconducting based current limiter. It is also required to improve the short-circuit capacity of the network and provide switchgear device where magnetic shielding material is much cheaper as compared to YBCO or BiSCo.
US 4158864 discloses a current limiting network which is connected in a power line between an AC power supply and a load, and has a pair of series connected resonant branch circuits, each of which include a capacitance and an inductance tuned to the power supply frequency. Under normal operation virtually no impedance is offered by the network. Each branch circuit has a circuit node between the capacitor and inductor contained therein. A switch, having a resistance in series therewith, is connected between the circuit nodes in the branch circuits. The branch circuits are connected in parallel, and a resistance is connected in parallel with the branch circuits. The switch is responsive to a fault current in the power system and when

actuated, detunes the series resonant branch circuits to thereby present impedance to the power line. The parallel resistance reduces the level of any transient surges and the time of any oscillation appearing on the capacitors when the switch is actuated by a fault current. However, the current limiting effect in the above patent is obtained by means of tuning the L and C parameter, which needs oversized inductor and capacitor bank along with huge punch grid resistor to dissipate the heat developed due to continuous rated current flowing through the resistors (R3-R4-R5). Neither this technology reveals about conditional operation of the device to discriminate the fault with temporary overload or surge current which lasts for few micro-seconds.
In WO/1999/05 3 5 90A direct grounding system prevents the instantaneous voltage drop known as the problem with the conventional grounding system, while utilizing the advantages of conventional direct grounding system. An inventive direct grounding system comprises a current limiter (3) that limits the ground-fault current on a downstream side of a breaker (10). The current limiter (3) may include a parallel circuit of normally closed commutation device and current-limiting impedance. When the electric current flowing through a distribution line exceeds a set value, the commutation device is opened to direct the current to the current-limiting impedance. Alternatively, the current limiter may be a superconducting device, semiconductor device or current-sensitive fuse that has a resistance value increasing with ground-fault current but zero resistance during normal operation. This patent discloses about a current limiter which limits the ground fault current using special superconducting device, semiconductor device or fuse. In case the limiter is with superconducting device, it will require a cooling unit to maintain the cryogenic temperature. This will increase the cost and size of the device. Also if the current limiter is fuse based than it will have higher watt loss, voltage drop and inconsistent operation due to variation in its performance. Similarly the semiconducting device owing to higher voltage drop will be subjected to higher watt loss and hence temperature rise even at rated current. To avoid this appropriate heat sink has to be used either with natural cooling or force cooling using fan. This will increase the overall size and cost of the device. There is a particular need to provide a device compact in size and less costly as compared to any other type of current limiter and which will discriminate the fault with temporary overload and short time surges.

US 4467298 a device which comprises of a simple means for holding the contacts apart and insulated from each other after circuit breaking. A screen formed by an insulating plate of small thickness, is placed between two mobile contact levers and is urged by springs against flanges which are integral with the levers and which move apart when short circuit currents appear for allowing this screen to be rapidly projected between the contacts inserts. The patent reveals about two current carrying parts, which separate apart at very high current due to holms and Lorentz repulsion force generated between the contacts. Early separation of the contacts is responsible for limiting the current and during this operation a thin insulating medium appears between the adjacent current carrying parts. As against there is clear need of a dedicated current limiter which will positively discriminate a temporary overload or surge conditions with a fault current and also which is capable of limiting a fault.
US 4164772 discloses a circuitry for limiting the instantaneous peak current, under fault conditions, of an AC power line, includes a high speed circuit breaker in series with a first capacitor in a main current-carrying branch, which branch is paralleled by two additional branches. According to various embodiments these branches contain various combinations of resistance, capacitance and spark gap elements whereby upon occurrence of the excess fault condition, the high speed circuit breaker opens. Thereafter the voltage buildup across the first series capacitor is sequentially commutated to a second branch having a capacitor and spark gap, with a predetermined arc-over voltage, and subsequently to a third resistive branch. The third branch effectively provides the peak current limiting impedance. The patent reveals about a circuitry for limiting the instantaneous peak current under fault conditions by means of commutating the current through several branches till it finally limited by the impedance. Capacitor unit which is in series with the circuit breaker contacts will increase the overall size of the arrangement. Also it calls for a bulkier size spark gap which is placed in the second parallel branch. It is required to provide a compact, less costly device which is capable of limiting a fault and to maintain controlled duration using fast acting switchgear device capable of clearing the fault with in one cycle.
In US2003021074 a modular and scalable Matrix-type Fault Current Limiter (MFCL) that functions as a "variable impedance" device in an electric power network, using components made of superconducting and non-superconducting electrically conductive materials. The

detection of a fault and subsequent activation of the current-limiting impedance of the MFCL are done passively by built-in matrix design, without assistance of active control mechanisms. The patent reveals about a superconducting & non superconductive electrically conductive material based current limiting technology. However it does not reveal about the conditional based impedance based current limiting technology which positively discriminate a real fault from temporary overload or surges with short duration of the order few micro-second.
In US2006034030 a surge current delay time period is added to a current limit delay time period in order to permit a longer time for a possibly temporary larger-than-steady-state electrical current, such as for a start-up power requirement. A system is described for permitting a legitimate surge current by distinguishing true over-current fault conditions from temporary surges in terms of high current duration time. The patent limits the fault current and provides a delay in limiting that by means of using an electronic circuit whose power circuit is based upon a MOSFET device, which is connected between the line and load. Owing to the limitation of the MOSFET current handling capacity it cannot be stretched for high fault current. Also the delay in current limiting technology is only suitable for short time rated surges. Under normal condition the MOSFET which is connected between the line and load will draw rated current which will lead to higher watt loss and hence temperature. This will demand appropriate heat sink which will increase its cost and overall panel size.
In US 2004/0027738, the invention is concerned with a resistive fault current limiter (FCL) based on thin superconducting films. The FCL comprises constrictions with a reduced critical current, separated by connecting paths. Upon occurrence of a fault current, the former turn resistive simultaneously and build up a resistance which allows the applied voltage to drop entirely only over the constrictions. Only at a later stage, the connecting paths become resistive and dissipate energy. The thickness and width of an electrical by pass determine said normal resistivity of the constructions and the connecting paths. The patent discloses about a resistive fault current limiter based on thin superconducting films. As we know that low temperature superconductor will operate at cryogenic temperature < 77 K. Hence will call for a costly, higher size and complicated cooling system. This will increase the overall cost and size of the device. On contrast to this the patent reveals about a current limiting technology which will operate even at room temperature.

In US 2005/0002152A1 described is a fault current limiting system includes switching means for providing a fast switching operation; a parallel current path comprising a limiting fuse; and a switching system to automatically replace a blown set of fuses with an unblown set of fuses after a fault current limiting operation has occurred. A method of limiting fault current includes providing a fast switching operation; providing a parallel current path comprising a limiting fuse; and automatically replacing a blown set of fuses with an unknown set of fuses after a fault current limiting operations has occurred.
This current limiting technology is based upon fuse sets which are connected in parallel with the fast switch contacts. As earlier pointed out the watt loss and hence temperature is very high even at rated current. Also fuse operation is highly unreliable due to its inconsistent performance.
Object of the invention
One object of the present invention is to provide room temperature conditional based impedance current limiting device, which below its critical current, field intensity and temperature will offer very low impedance in few milliohms so that the net voltage drop of the system is very low.
Another object of the invention is to provide a current limiting device with low voltage drop, watt loss, temperature rise and cost as compared to solid state switch current limiting device, which does not require special cooling unit to maintain cryogenic temperature, also which improves the short-circuit capacity of the network and existing switchgear device and where magnetic shielding material is much cheaper.
Yet another object of the present invention is to provide a current limiting device which discriminates the temporary overload condition with actual fault and which can be easily plugged into its base for ready mounting on panel and easy to manufacture.
Summary of the invention
The conditional based impedance consists of a ferromagnetic core, diamagnetic material sim, bobbin, copper coil, upper and lower terminal plate, DIN type copper terminal, and insulated housing. The ferromagnetic core is surrounded by a diamagnetic material sim, which are

inserted inside the bobbin over which the coil with suitable number of turns is wounded. Over
the bobbin at the top and bottom hallbach array (3 ALNICO based rectangular permanent
magnet adjacent to each other) are placed. The coil, core, sim and the hallbach array is suitably
moulded with start & end winding projecting out. The entire unit is placed inside a moulded
housing with top and bottom terminal plate along with copper current carrying terminal
attached to it. The start and end winding of the coil is welded to the incoming and outgoing
terminal of the impedance.
Description of drawings:
Figure -1 shows the room temperature conditional based impedance current limiter along with
the base.
Figure - 2 shows the current limiter with single winding without mounting upon the base plate
Figure - 3 shows the core of the limiter
Figure - 4 shows a hollow cylinder
Figure - 5 shows the bobbin upon which the coil is wound.
Figure - 6 shows the coil consisting of single layer of copper conductor which is tightly wound
over the insulated bobbin
Figure - 7 shows the epoxy resin cast part (15) of the winding.
Figure - 8 shows rectangular insulated housing
Figure- 9 shows terminal plate
Figure - 10 shows terminal with rectangular shape with wedge provided on side
Figure -11 shows base assembly of the current limiter
Figure -12 shows a base with rectangular insulated bar with two counter shank holes (31)
provided for mounting the base plate.
Figure - 13 shows position of front plate placed at the top and bottom of the base plate.
Figure - 14 shows contact lip above front plate
Figure - 15 shows a circlip
Figure - 16 shows stop plate (L shaped steel sheet) with a bend
Figure- 17 shows the complete assembly of the current limiter with two windings where the
current is shared in parallel
Figure -18 shows single winding (2 SWG copper wire) is used with two layer in series with
each other for higher rated current

Figure-19 shows the temperature rise of outer body surface.
Figure-20 shows the temperature rise of terminal of the device.
Figure-21 shows the relationship between the rms current and maximum peak current
Figure-22 shows the variation of the resistance, dynamic reactance and impedance of the
device at different fault current.
Figure-23 shows the peak current limited by the conditional based impedance at different
prospective fault current.
Figure-24 shows the temperature rise of outer body surface at 50 A.
Figure-25 shows the temperature rise of terminal of the device at 50 A

Detailed description:
The conditional based impedance consists of a ferromagnetic core (1), diamagnetic material sim (2), bobbin (3), insulated potted copper coil (4), upper and lower terminal plate (5), DIN type copper terminal (6), and insulated housing (7). The core (1) which is coaxially located at the centre of the current limiter is cylindrical in shape and is made out of ferromagnetic material. The core (1) of the limiter is surrounded by a sim (2), which is inserted inside the bobbin over which the coil with suitable number of turns is wounded. The sim (2) is a hollow cylinder and is made out of diamagnetic material. Bobbin (3) is made out of insulating material such as nylon and is cylindrical (10) in shape. It consists of upper (11) and lower (12) flange which is attached with the cylindrical body. The coil is wound on the bobbin. At the upper & lower flange provision has been given by means of a cut (13) to route the start and end winding of the coil to the copper terminal. The coil (4) consists of single layer of copper conductor which is tightly wound over the insulated bobbin and is hollow cylindrical in shape (14). Over the bobbin (3) at the top & bottom (11 & 12) hallbach array (8) are placed. This array is made out of 3 ALNICO based rectangular permanent magnet placed adjacent to each other. The coil, core, sim and the hallbach array (8) is suitably moulded with start and end winding projecting out. The entire unit is placed inside an insulated housing (7) with top and bottom terminal plate (5) along with copper current carrying terminal (6) attached to it. The insulated housing (7) as shown in is rectangular (16) in shape with a hollow cylindrical hole (17) provided at its centre. This is given for easy entry of the epoxy casted impedance. At its upper (18) & bottom (19) surface, four holes (20) for screw fitment of the terminal plate are given. Terminal plate (5) consists of a rectangular sheet made out of steel sheet. At its central axis slot (21) has been provided for easy entry of terminal and copper conductor which is welded with respect to each other. Four holes have been provided upon its surface so as to fit it with the housing. The start and end winding of the coil is welded to the incoming & outgoing terminal of the impedance. The terminal (6) is a rectangular (23) in shape with a wedge (24) provided at both the sides so that it can easily enter into the spring clip of the base. The complete base assembly (9) of the current limiter consists of base (25), contact lip (26), stop plate (27), front plate (28), circlip (29) and terminal assembly (30). The base (25) is a rectangular insulated bar with two counter shank holes (31) provided for mounting the base plate. A rectangular slot (32) is provided at its upper surface (25) so as to fit the front plate

(28) upon it by means of screw fitment through the holes (33). At the bottom surface, two oval shape slots (34) are provided, which is meant for resting of the head of the screw which connects the entire front plate assembly with the base plate. In order to save the insulating material and for propare mould flow alternate rectangular slots (35) have been provided on the bottom surface of the base plate. Upon the insulated base plate (25), front plate (28) is placed at the top and bottom of the base assembly. The front plate is a L shaped (36) steel sheet with a projected threaded groove (37) for fitment of the plate with respect to other parts such as contact lip and stop plate. At its bottom surface the profile is slightly tapered (39) and a rectangular cut (38) is given to remove the excess material. This makes the front plate to provide a spring like action for fitment of the current limiter terminal. Above the front plate a contact lip (26) is placed which is made out of ETP Vi hard copper materials. It is L shaped sheet with projected collar (40) at its two adjacent sides so as to get a grip between the front plate & base plate. Similar to that of the front plate, at its bottom surface, is provided with a cut (41 and 42) which allows the current limiter to enter into it. In between the two a circlip is placed. It is made out of spring steel material and is circular disc shaped. At its bottom end an opening cut (43) has been provided for easy entry of the DIN type copper terminal. Also two protrusion (44) is provided, which is meant for providing a grip between the front and contact lip. In order to restrict the motion of the assembly constituting front plate, contact lip and circlip, a stop plate is firmly gripped through a screw fitment. The screw head rest upon the front plate (33) and its length extends up to the stop plate (44). The stop plate is L shaped steel sheet with a bend (45). Similar to that of the front plate and contact lip, a rectangular cut (47) and tapered profile (46) is provided at its bottom surface.
For very low rated current limiter (< 25 A) single winding(9 SWG copper wire) is used whereas for moderate current range (> 25 A < 50 A) two windings(9 SWG copper wire) are connected in parallel closed to each other so that the windings fall one above the other. The space between the layers is sufficiently maintained so as the make the mutual inductance effect as negligible as possible. In one embodiment complete assembly of the current limiter with two windings where the current is shared in parallel. This is done to reduce the temperature of the device. Due to this arrangement the effective inductance is equivalent or slightly less to that of the self inductance of a single winding. For higher rated current limiter (>50A < 100 A) single winding (2 SWG copper wire) is used with two layer in series with each other. In this

type the entire unit consisting of ferromagnetic core, sim, coil, hallbach array, upper, bottom terminal is epoxy moulded so as to fit the entire unit within the same height. The DIN type copper terminals are made suitable to fit into a base (9) for mounting into the panel. At very low current the presence of diamagnetic material surrounding the ferromagnetic core restricts the main flux to enter into the core radially. The flux generated by the outer surface of the top and bottom array will oppose the main flux that is generated by the coil surrounding the ferromagnetic material. So below critical parameter of the device, the main flux is fully opposed by the diamagnetic material and Hallbach array, this makes the resultant flux to be negligible. Due to which the inductance of the conditional based impedance is negligible and the total impedance is offered by its resistive component. Above its critical parameter, the main flux overrides the residual flux generated by the hallbach array and it enters into the ferromagnetic core thereby increasing the dynamic inductance of the device, which is directly proportional to the permeability of the ferromagnetic core and square of the number of turns of the coil. The variation of the inductance & hence the impedance with respect to the fault current is a nonlinear curve similar to that of permeability curve of the ferromagnetic material. While limiting the fault current, the windings of the conditional based impedance is subjected to dynamic electromagnetic force, which may cripple the windings. To avoid this iron core inductor along with the hallbach array is epoxy moulded. Unlike to a fuse which can be used for once, the conditional based impedance is suitable for multiple operations. The current density of the copper conductor is kept near to 3 A/mm2 so that the overall absolute temperature is within its specified limit. The DIN type copper terminals are made suitable to fit into a fuse base for mounting into the panel.
The current limiting technology disclosed overcomes all the problems associated with various types of conventional fault current limiter. It avoids the requirement of a cooling unit to maintain the cryogenic temperature which reduced the overall cost and size of the device. Also it does not require magnetic shielding unit with superconducting material such as YBCO & BiSCo which is very costly. Present low rated MCCB offers a fault level of 10 KA whereas the patent disclosed aids in improvement of the fault level. Due to low voltage drop, the resistive power loss and size of this device is much less as compared to a solid state switch based fault current limiter. Its performance in terms of resistive wattloss, temperature, usage and reliability is much better than a conventional fuse.

Presently for current limiting and short circuit protection we are using switchgear devices along with fuse. For illustration the inclusion of this device in series with the incoming line will improve the short circuit rating of the switchgear devices. Though it is a simple ferromagnetic core inductor but it consists of a magnetic shielding arrangement, which aids in distinguishing the fault from temporary overload condition. This is obtained due to special composite material consisting of ferromagnetic, diamagnetic and permanent magnet array in the device.
Temperature rise test result at 10,16,20 and 25A:
With the conditional based impedance plugged onto a HB 100 fuse base, temperature rise test conducted at various current level from 10 A to 25 A till the temperature got stabilized. Surrounding ambient temperature of the device maintained at 37°C. Figure - 2 and 3 shows the temperature rise of outer body surface and terminal of the device. The maximum temperature rise of the copper terminal observed to be 25°C which is less than the specified limit (50°C).
Short circuit test result at different fault current
The device is mounted as under normal practice and short circuit test conducted at fault current varying froml KA to 35 KA rms, 240V, 50Hz. Corresponding to this current the peak current is equivalent to 73.5 KA. Figure - 4 shows the relationship between the rms current and maximum peak current as per when the impedance is not inserted between the line and load. However when it is included, the current limiting effect is prominently seen above a critical current of 3 KA.
Below critical current there is no current limiting effect as the ferromagnetic and diamagnetic material combinations along with permanent magnet array magnetically shield the device. The shielding effect is done by means of opposing the main flux to enter into the ferromagnetic core. At this stage the impedance is purely resistive in nature. Beyond the critical current the main flux is sufficient to override the flux (0.12 mT) generated by the permanent magnet array which are placed at the top and bottom of the core. This makes the device to change from resistive to impedance with high dynamic inductance. The inductance and hence the impedance follow the characteristics similar to that of the permeability curve of the ferromagnetic material. This is because the inductance of the conditional based impedance is proportional to permeability of the ferromagnetic material.

Due to the variation in the impedance of the device the peak fault current limited by a maximum of 75%. Peak current limited by the conditional based impedance at different prospective fault current. From the curve it is clear that below critical current of 3 KA the current is not limited as the device is resistive in nature. However beyond 3 KA, since the main flux overrides the critical flux (0.12mT) there is positive increase in the inductance and hence impedance which limited the peak current. This shows the conditional behavior of the impedance similar to that of a superconducting fault current limiter but at room temperature. Presently the technology has been proved by means of passing the current for only 20 ms, which has to be maintained through a protective device which clears the fault within 0.01s. In such a case the device can be used repeatedly for multiple operations without causing any damage to it.
The foregoing descriptions of specific embodiments of the present invention have been presented for purposes of illustration and description. They are not intended to be exhaustive or to limit the present invention to the precise forms disclosed, and obviously many modifications and variations are possible in light of the above teaching. The embodiments were chosen and described in order to best explain the principles of the present invention and its practical application, to thereby enable others skilled in the art to best utilize the present invention and various embodiments with various modifications as are suited to the particular use contemplated. It is understood that various omission and substitutions of equivalents are contemplated as circumstance may suggest or render expedient, but such are intended to cover the application or implementation without departing from the spirit or scope of the present invention.

We claim:
l)Condition based impedance current limiter comprising:
at least one cylindrical bobbin, the bobbin having cavity along its axis;
at least one coil, the coil wound around the said cylindrical bobbin and the coil covered with
epoxy coating;
at least one core, the core made of ferromagnetic material and surrounded by diamagnetic sim
and placed inside the cavity of the said bobbin;
a hallbach array, the array being a permanent magnet placed at the ends of the said bobbin;
an insulated housing, the said housing with top and bottom terminal plate and placing the said
coil-hallbach array assembly inside said housing;
a base plate for mounting the said housing;
Wherein at lower current below set critical parameter value, the diamagnetic material
surrounding the ferromagnetic core restricts the main flux to enter into the core radially and
the flux generated by the outer surface of the top and bottom array will oppose the main flux
generated by the coil surrounding the ferromagnetic material and at higher current above
critical parameter value, the main flux overrides the residual flux generated by the hallbach
array and it enters into the ferromagnetic core and increases the dynamic inductance of the
device.
2) Condition based impedance current limiter of the claim 1 wherein, temporary overload condition is discriminated from the fault condition.
3) Condition based impedance current limiter of the claim 1 wherein, number of coils can be connected in series or parallel based on the rated current value.
4) Condition based impedance current limiter of the claim 1 wherein, below critical current there is no current limiting effect as the ferromagnetic and diamagnetic material combinations along with permanent magnet array magnetically shield the device and beyond the critical current the main flux is sufficient to override the flux generated by the permanent magnet array.
5) Condition based impedance current limiter of the claim 1 wherein, for very low rated current limiter (< 25 A) single winding (9 SWG copper wire) is used for moderate current range (> 25 A < 50 A) two windings (9 SWG copper wire) are connected in parallel and for higher rated current limiter (>50A < 100 A) single winding (2 SWG copper wire) is used with

two layer in series with each other.
6) Condition based impedance current limiter as described in any of the accompanying
drawings.