TITLE: A DEVICE FOR MOUNTING OF CONDUCTOR IN ISOLATED PHASE
BUSDUCT (I.P.B) WITH THE HELP OF THREE INSULATORS. 120°
DEGREE APART OUTSIDE THE CONDUCTOR.
FIELD OF THE INVENTION
The present invention generally related to a '120 degree three insulator out side
conductor mounting' for Isolated Phase Busduct device. More particularly, the
present invention relates to a 120 degree three insulator conductor mounting
device for isolated phase bus duct (IPB) with mechanical stability even in the
event of failure of one of the insulator.
BACKGOUND OF THE INVENTION
IPB device is adaptable in between Generator and Generator Transformer of
power generating plant up to a capacity of 250 MW. The busduct is a conductive
device which carries current at high voltage [HV] as well as at medium voltage
[MV]. The isolated phase busduct conductor is of round/ rectangular or
octagonal cross sectional shape. The conductor is housed in round enclosure.
The mounting of conductor with its enclosure is to be accomplished, keeping in
view of the parameter like over all safely, the short circuit forces, the minimum
electrical clearances requirements and the creepage requirements as per KV
class of busduct. Isolated phase busduct [IPB] is connected between Generator
and Generator Transformer in a Power Generating Station. In between a
Generator and Generator Transformer tap off busduct from main busduct is
connected to various power plant equipment like SPVT cubicle, NG Cubicle,
Excitation Transformer, Unit Auxiliary Transformer etc.
The manufacturers of busduct are making very simple and conventional
mounting arrangement since long period. But over the years many practical
problems were observed and addressed by various design changes. Still there
were many scope for enhance features which have been implemented in the
present invention.
Earlier and existing mounting arrangement were not addressing;-
a. The supporting deficiency at rigid mounting locations due to thermal
expansion/ contraction.
b. The requirement lateral alignment of conductor during short circuit force
condition.
c. The issue of standardization in hardware length.
d. The higher level and duration of short circuit fault level as at present.
e. The stringent requirement of air leakage within 5% approx and also
meeting air and water tightness requirement as per standard.
f. Capability of Busduct conductor mounting arrangement to sustain
seismic excitation.
g. Providing mechanical stability with 120° three insulator conductor
mounting even in the event of failure of one insulator.
OBJECTS OF THE INVETION
It is therefore, an object of the present invention to propose improvements in
conductor mounting device of isolated phase busduct which eliminates the
deficiencies in prior art.
Another object of the present invention is to propose a sliding and rigid
conductor mounting device of isolated phase busduct which is perfectly and
centrally fitted with the enclosure and 120° three insulator conductor mounting
remains mechanically stable even in the event of failure of one insulator.
A still another object of the present invention is to propose a sliding and rigid
conductor mounting device of isolated phase busduct wherein air/water leakages
are within permissible limit.
A future object of the present invention is to propose a sliding a rigid conductor
mounting device if isolated phase busduct sustains forces generated in the event
of short circuit in the power plant.
A still future object of the present invention is to propose a sliding and rigid
conductor mounting device of isolated phase busduct which provides flexibility in
axial direction for expansion and contraction due to change in temperature.
An yet further object of the present invention is to propose a sliding and rigid
conductor mounting device of isolated phase busduct with its enclosure which
standardizes hardware irrespective of enclosure sizes.
A still unique object of the present invention is to be propose 120 degree three
insulator conductor mounting device for Isolated Phase Busduct to provide
mechanical stability even in the event of failure of one of the insulator which is
not existing in the present arrangement used world wide as they are only press
fit.
SUMMARY OF THE INVENTION
One common type of conductor mounting device [rigid/sliding] is installed for all
the three phases of the busduct and throughout the entire length of busduct.
Three insulators are placed and disposed at 120° apart between first Insulator to
second Insulator and again 120° apart from second Insulator to third Insulator.
The mechanism for mounting arrangement with busduct enclosure is common
for all the three insulator position as shown in figure -1 which are 120° apart.
The mounting device at insulator top with the conductor comprising
A. Belleville washers in series stacks.
B. Guide pin for locating & retaining in position.
Conductor is fastened with the insulator through Belleville washers in series
stacks and tide with guide pin as shown in figure 3. The conductor has slots
along the length of the conductor to permit expansion/ contraction to temp
variation.
TEST CONDUCTED
The specimen type test assembly of busduct meeting to requirements of IS:
8084 has been validated by type tests and have successfully passed the tests
for:
a. Short circuit fault level of 168 KA rms for 1 sec/421 KA peak as per IS:
8084. at CPRI, Bhopal.
b. Simulated seismic excitation independently along vertical and two
orthogonal horizontal axes, +/-0.3 g horizontal for a minimum duration of
30 sec. In each case at IIT. Madras per IS: 1983.
c. Air and water tightness tests as per IS: 8084 appendix-F
BRIEF DESCRIPTION OF THE ACCOMPANYING DRAWING
Fig-1 Shows a schematic diagram for three insulators conductor mounting with
120° placements.
Fig- 2 & 4 shows an enlarged schematic diagram for 120° conductor mounting
device for LP. Busduct enclosure with insulator's bottom and conductor with
insulators Top . This is common for other insulators also.
Fig-3 Shows a schematic diagram for 120° conductors mounting for LP. Busduct
with Belleville washer stacks and guide pin arrangement.
DETAILS DESCRIPTION OF A PREFERRED EMBODIMENT OF THE
INVENTION
The invention will now be described with the help of the accompanying drawing
which depict an exemplary embodiments of the invention. However, there can be
several other embodiment, all of which are deemed covered by this description.
Fig - 1 Shows the position of all the three insulators (3) mounting for conductor
(1), one at middle/ bottom (Middle) and other two disposed at 120 degree (LHS
& RHS) around the busduct enclosure and conductor.
Fig - 2 Shows the enlarged view of one of the insulator mounting arrangement
between enclosure and conductor.
The enclosure (E) has 200 mm dia holes at 120° apart to accommodate insulator
support base sub assembly (8). The enclosure sealing is achieved by sealing
gasket (5). The sealing confirms to air water tightness requirements.
Eight numbers of hex head screw [7] of adequate length are provided with
gasket (5) on the insulating support base plate (8). Further circular cast/ rolled
block is welded over enclosure on which this insulator base is tightened with
above hardware. Towards conductor side the insulator (3) is fixed with Belleville
washer (2) and guide pin (1)
The whole assembly as shown in Fig-2, now acts as resilient and air/ water proof
arrangement for busduct conductor support.
Fig - 3 shows the arrangement of mounting of the conductor [C] with insulation
[3] top. Belleville washer stacked with guide pin is provided at the top. This
device offers a firm grip to the conductor (C) with insulator (3).
Fig - 4 shows the insulator (3) mounting with enclosure (E). In this
arrangement 200 dia. Hole on enclosure (E) cut-out. On this a sub assembly of
insulator supports plate (8) with gaskets (4 and 5) and hardware (6 and 7) are
fixed.
KEY FEATURES
Reference Items/features
Figure
Character
1 Guide pin 1,2,3
2 M20 Belleville washers 1,2
4 Rubber gasket 1,2,4
5 Gasket 1,2,4
9 Aluminium cast/rolled block 1,2,4
6 Washer Spring M-16 1,2,4
6 MCD Washer M-16 1,2,4
6 Hex.HD. Screw Steel M 16 1,2,4
7 Hex. Head Screw M10 1,2,4
7 Spring Washer. M10 1,2,4
7 Machined Washer, M10 1,2,4
3 Support Insulator 1,2,3,4
Reference character Items/Features Figure
C Al.alloy conductor 1,3
E Al.alloy enclosure 1,4
L Left side insulator 1
R Right slid insulator 1
M Bottom insulator 1
WE CLAIM
1. A Device for mounting of conductor in isolated phase busduct (IPB) with
the help of three insulators, 120 degree apart outside the conductor.
- a plurality of insulators (3) mounting for conductor (c);
- a plurality of insulators support base sub assembly (8) to
accommodate support insulator;
- an enclosure (E) for conductor & insulator with a plurality of holes
at 120° apart;
- a plurality of sealing gasket (5) along with a plurality of hexagonal
head screens (7) provided for enclosure sealing;
- a circular cast/rolled block, welded over enclosure (E) on which this
insulator base is tightened with above hardware;
- a plurality of Belleville washers (2) and
guide pin (1), to fix the insulator (3) towards the conductor side,
wherein the mounting arrangement with placement of identical
insulators at 120° apart from each other between conductor &
enclosure with Belleville waster stacks & grid pin, provides
mechanical stability herein the event of failure of one of the
insulators.
2. The device as claimed in claim 1, wherein insulators (3) are identical and
fixed at 120° apart, keeping one at the middle or bottom and other two
disposed at 120° (LHS and RHS) around the busduct enclosure (E) and
conductor (C).
3. The device as claimed in claim 1, wherein the enclosure (E) has holes of
200 mm dia at 120° a part to accommodate insulator support base sub
assembly (8).
4. The device as claimed in claim 1, wherein the gasket (5) is provided for
enclosure sealing from water and dust.
5. The device as claimed in claim 4, wherein said enclosure sealing is done
with gasket (5), provided with eight numbers of hexagonal head long
screws (7) on the insulating support base plate (8).
6. The device as claimed in claim 1, wherein said fixing of insulator (3)
towards the conductor side with Belleville washer stacks & providing
guide pin which gets into insulator on top side & into slot provided in the
conductor at other end.
7. The device as claimed in claim 1, wherein the conductor (C) has slots
along the length of the conductor to permit expansion/ or contraction
due to temperature.
8. The device as claimed in claim 1, wherein the guide pin is provided for
locating & retaining in position.
9. The device as claimed in claim 1, wherein said conductor (C) mounted is
centrally disposed with the enclosure.

A Device for mounting of conductor in isolated phase busduct (IPB) with the help of three insulators, 120 degree apart outside the conductor, a plurality of insulators (3) mounting for conductor (c); a plurality of insulators support base sub assembly (8) to accommodate support insulator; an enclosure (E) for conductor & insulator with a plurality of holes at 120° apart; a plurality of sealing gasket (5) along with a plurality of hexagonal head screens (7) provided for enclosure sealing; a circular cast/rolled block, welded over enclosure (E) on which this insulator base is tightened with above hardware; a plurality of
Belleville washers (2) and guide pin (1), to fix the insulator (3) towards the conductor side, wherein the mounting arrangement with placement of identical insulators at 120° apart from each other between conductor & enclosure with
Belleville waster stacks & grid pin, provides mechanical stability herein the event of failure of one of the insulators.