FORM 2
THE PATENTS ACT, 1970 (39 of 1970)
COMPLETE SPECIFICATION
(See section 10 and rule 13)
1. TITLE OF THE INVENTION
Encapsulated dropper supporting system for vertical bus
A Novel current sensing and associated signal processing technique for reducing measurement error.
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
COMPLETE
The following specification particularly describes the 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 applicant(s)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

Encapsulated vertical bus supporting system Field of the invention
Present invention relates to encapsulated vertical bus supporting system in power distribution modules. More particularly the invention relates to dropper support design which provides for an encapsulated dropper supporting system to prevent access to the live busbars.
Background of the invention
A switchboard is a mechanical structure that encompasses a large variety of switchgear including
power gear and control gear equipments arranged logically in order to enable power distribution
to various loads at the end user premises. In short the switchboard is the heart of the power
distribution system.
An LV power distribution circuit is divided into Power Control Centre (PCC) in the upstream
and Motor Control Centre (MCC) in the downstream.
A very basic MCC panel consists of the following:
(i) Horizontal Busbar (Busbar that runs throughout the length of the panel which consists of
one or more bars placed in parallel planes and are responsible for carrying and delivering
the required current to the individual circuits)
(ii) Distribution feeders or modules (They consist of powergear like MCCB / SDF & controlgear like Contactors and Relays)
(iii) Vertical Busbar or Dropper (Used for feeding current to the individual distribution circuits and are placed such that their thin edges lie in a single plane.)
(iv) Supporting system for Vertical busbar which consists of individual support members that are electrical non-conductive i.e. made of an insulating material which shall provide strength to the vertical bus in case of a short-circuit, at the same time providing sufficient creepage distance between phases.
US Patent 6664478 provides support members for a busbar assembly. The support members include a body formed of an electrically insulating material and at least one receiving formation in the body and configured to receive an electrical conductor. A strengthening insert is located substantially entirely within the body to electrically insulate the strengthening insert from the

electrical conductor. The strengthening insert is a material different from the electrically insulating material of the body. Support structures and busbar assemblies and methods of making the support members are also provided.
Another US Patent 6549428 provides a device for supporting and fix bus-bars in cabinets for switchboards which consists of a first element, constituted by a body made of insulating material, which has a first side provided with means for direct engagement to a supporting frame and a second side provided with a plurality of first seats for coupling to corresponding bus-bars, wherein a protrusion is formed on the surface of the first seats, said protrusion being shaped for snap-together coupling to a corresponding slot of a bus-bar; a second element, constituted by a body made of insulating material which has a shaped side along which a plurality of second seats are provided for coupling to said bus-bars, said first and second elements being mutually connected in order to geometrically couple said first and second seats and to clamp the bus-bars inside the seats.
Yet another US Patent 4822951 provides a busbar arrangement for a switchgear assembly where the load buses pass through apertures in riser supply buses the load buses are supported by the supply buses by insulating grommet blocks occupying the space between the load buses and the inner edges of the apertures. The grommet blocks are held in place by sleeves on the load buses. However the existing system has following limitations:
a) Lower short circuit withstand rating
b) Additional barrier requirement
c) Non-standardization due to different module heights
d) Difficult assembly of insulating supports
e) Poor flexibility of contact fixing
High electro-dynamic forces occur on the conductor during a short circuit and hence supports are provided to withstand these forces and dropper supporting system is required to prevent any damage to the conductor in the event of a short circuit. In existing switchboards, the supporting system can be used for lower short circuit fault ratings only and does not provide for encapsulation which makes use of additional separators mandatory.

Object of the invention:
Object of the present invention is to provide a dropper supporting system is to prevent damage to the conductor in the event of a short circuit. High electro-dynamic forces occur on the conductor during a short circuit and hence supports are provided to withstand these forces.
Another object of the present invention is to provide a unique dropper support design which provides for an encapsulated dropper supporting system such that after the complete assembly procedure of assembling the dropper supports no external barriers/shrouds are required to prevent access to the live busbars.
Another object of the present invention is to provide a unique rib structure which forms the shape of a honeycomb that is a crisscross rib pattern with ribs extending from one boss and moving towards another in all directions providing high strength withstand capability during the event of a short circuit fault.
Summary of the invention:
Supporting arrangement for vertical bus system is provided. The vertical bus is placed in the dropper seat. Semi-circular ribs are provided at equal distances to enhance rigidity during the event of short circuit enabling it to handle the electro-dynamic forces. The entire straight rib as a whole prevents access to the live dropper from the left side. In the region between the second and third rib structures, material filling is done at two locations since that region of the supporting structure is intended to withstand the forces coming from the conductors on two sides instead of one. The same pattern gets repeated for the next set of ribs. The rear side of the support has a honeycomb structure which gives immense rigidity for withstanding the electro-dynamic forces. The ribs extend on all sides symmetrically around the circular for unanimity of rigidness throughout the support.
Description of the Drawings:
Figure 1: Dropper support front view highlighting dropper seats, rib pattern etc. Figure 2: Back side view showing the unique honeycomb pattern with bosses and ribs Figure 3: Two supports assembled depicting encapsulation Figure 4: Dropper assembly showing placement of droppers in the dropper seat

Figure 5: Rib used for encapsulation process Figure 6: Slot for encapsulation Figure 7: Step for preventing access and encapsulation Detailed Description:
The foregoing objects of the present invention are accomplished and the problems and shortcomings associated with the prior art, techniques and approaches are overcome by the present invention as described below in the preferred embodiments.
The present invention applies to LV switchgear and control gear assemblies which are defined as having Input System Voltage < 1000V for ac systems and < 1500V for dc systems. Following important parameters are to be kept in mind while designing and selecting switchboards for a particular application:
(i) Type of application Indoor, outdoor, residential, industrial etc.
(ii) Current rating of Busbars
(iii) Circuit breaker rating
(iv) No. of outgoing (o/g) feeders
(v) Short circuit breaking, making and withstand capacities
(vi) Thermal performance (Temperature rise)
(vii) Internal arc withstand capability (Special Test)
(viii) Seismic withstand capability (Special Test) This arrangement supports the vertical bus system during the event of a short circuit when large electrodynamic forces occur on the system wherein large attractive and repulsive forces occur between two conductors depending on the direction of the current flow. The vertical bus is placed in the dropper seat as shown by 6 in figure 4. The holes for fixing of the vertical bus with the dropper support as shown by 12 in figure 8. Semi-circular ribs are provided as shown by 1 in figure 1 at equal distances to enhance rigidity during the event of short circuit enabling it to handle the electrodynamic forces. The entire straight rib as a whole prevents access to the live dropper from the left side. As shown by 2 in figure 1, in the region between the 2nd and 3rd rib structures, material filling is done at two locations since that region of the supporting structure is intended to withstand the forces coming from the conductors on two sides instead of one. The same pattern gets repeated for the next set of ribs. As shown in figure 2, the rear side of the

support has a honeycomb structure which gives immense rigidity for withstanding the electrodynamic forces. The ribs shown by 3 in figure 2 extend on all sides symmetrically around the circular bosses (shown by 4 in figure 2) for unanimity of rigidness throughout the support. The scooped area ensures equal part thickness to avoid molding difficulties.
Obtaining encapsulation and rear access prevention:
The important features that help in achieving the encapsulation and rear access preventions are shown by 5 in figure 3, the ribs shown by 8 in figure 5, slot shown by 9 in figure 6 and step shown by 10 in figure 7. As shown in figure 5, the ribs fit into the space provided by the slot shown by 9 in figure 6 and the step shown by 10 in figure 7 which ensures that there is no gap remaining after complete mating of the supports.
Obtaining front access prevention:
As shown by 11 in figure 8. 6 numbers of holes are provided for fixing front barriers. Thus,
using this feature, a barrier can be fixed on the insulating support itself and is not required to be
fixed on the structural member or any other region of the switchboard. This can be done using
self-tapping screws which works well for connection of the barrier onto the support.
This provides encapsulation and eliminates use of external separators and sleeving of bus. At present sleeving is used as a safety feature for operator. Wear out of bus sleeving could occur over continuous use, or due to some abnormal heat occurring in the system thereby compromising on operator safety. Complete encapsulation ensures IP4X protection and 100% safety for operator. Also present supporting system uses bolts and nut-plate combination for fixing of vertical bus feeder contacts. In this invention, the insulating support has moulded inserts as shown by 12 in figure 8 which leads to single point fixing for vertical bus as well as feeder contacts thereby eliminating use of nut plate and reducing the assembly time.
Some of the salient features and advantages of the invention are as follows:
1. Insulating Support has a very unique rib structure which forms the shape of a honeycomb, which is a crisscross rib pattern making the support highly rigid in nature.
2. Rigid design makes it suitable for use for short circuit withstand above 50kA.

3. Placing of the supports in the assembly is such that it provides complete encapsulation, thus eliminating the use of additional barriers to prevent access.
4. Moulded inserts used in the support enable single point fixing for the vertical bus and the feeder contacts, giving greater flexibility for feeders.
5. Holes provided on the front enable easy fixing of front barrier using self tapping screws.
6. Stacking of supports one below the other makes the assembly simpler and reduces the overall assembly time as compared to the existing system of vertical bus supporting, thus eliminating the requirement for high skilled labor for assembly.
7. Post assembly encapsulation provides complete IP4X protection enhancing operator safety.

We claim,
1) Encapsulated vertical bus supporting system for low voltage switchgear control
assemblies comprising:
atleast one insulating dropper seat having slot for holding vertical bus, a vertical bus mounted in the said slot in the dropper seat,
rib structure along the edges of said slot in the dropper seat, the rib having alternate semicircular and linear profiles forming honeycomb shape,
wherein, the dropper provides encapsulation to the bus thus preventing access to the live bus system.
2) Encapsulated vertical bus supporting system for low voltage switchgear control assemblies of the claim 1 wherein, moulded inserts are used in the dropper seat enable single point fixing for the vertical bus and the feeder contacts, giving greater flexibility for feeders.
3) Encapsulated vertical bus supporting system for low voltage switchgear control assemblies of the claim 1 wherein, plurality of dropper seats are stacked one above another to provide complete vertical encapsulation
4) Encapsulated vertical bus supporting system for low voltage switchgear control assemblies of the claim 1 wherein, insulating dropper seat has moulded inserts for single point fixing for vertical bus as well as feeder contacts.
5) Encapsulated vertical bus supporting system for low voltage switchgear control assemblies of the claim 1 wherein, in the region between the 2nd and 3rd rib structures, material filling is done at two locations to withstand the forces coming from the conductors.