AU2018100702A4

AU2018100702A4 - Improved electrical recloser

Info

Publication number: AU2018100702A4
Application number: AU2018100702A
Authority: AU
Inventors: Joni Sahak Tortian
Original assignee: NOJA POWER SWITCHGEAR Pty Ltd
Current assignee: NOJA POWER SWITCHGEAR Pty Ltd
Priority date: 2013-10-15
Filing date: 2018-05-24
Publication date: 2018-06-28
Anticipated expiration: 2022-10-07
Also published as: AU2014240335A1

Abstract

A recloser (100) for use in an electrical circuit, the recloser including: a housing (102) formed of one or more housing panels (202a, 202b, 202c); and one or more reinforcement panels (200a, 200b, 200c) for reinforcing said one or more housing panels, wherein the reinforcement panels (200) are mounted internal to the housing (102) and in facing relation to said housing panels (202) to shield the housing panels from damage by internal electrical arcing. Suitably, the reinforcement panels (200) are mounted to the ends, sides, bottom and/or roof of the housing (102) and arranged to impede the internal electrical arc from contacting the housing panels (202). (Figs 2a-2c) ~I6. 22o fl4*~~ Ft7~ 2

Description

IMPROVED ELECTRICAL RECLOSER TECHNICAL FIELD

[0001] The present invention generally relates to electrical switchgear, particularly reclosers.

BACKGROUND

[0002] The reference to any prior art in this specification is not, and should not be taken as, an acknowledgement or any form of suggestion that the prior art forms part of the common general knowledge.

[0003] Reclosers are medium voltage circuit breakers used outdoors on overhead power lines and substation applications usually between 10-38kV. Reclosers operate to detect over current faults on a line, and then break the current path, to thereby interrupt power supplies. After the over current has passed, the recloser closes again, thereby restoring the current path.

[0004] This operation is typically performed multiple times, to allow transient faults such as lightning strikes, to be interrupted, thereby preventing damage to power lines and distribution equipment. Typically the fault is interrupted within 200 milliseconds and supply is restored within 500 milliseconds to several seconds.

[0005] In general, all reclosers include a switching element contained within a housing. The switching element is at line voltage and may experience over voltage during faults, accordingly, it is necessary to have the switch insulated. This is typically achieved by mounting the switching element in a housing, and then filling the housing with either oil or SF6 gas to insulate the switch. However, this suffers from a number of disadvantages.

[0006] In particular, both oil or SF6 gas are dangerous to the environment. When an arc fault occurs the oil or gas is heated rapidly, causing the oil or gas to expand. This can lead to the housing being ruptured, releasing the oil or gas into the environment. In addition to this, the oil or gas can be released at high temperatures and pressures. This can lead to ignition of fires, as well as injury to any individuals in the vicinity.

[0007] An improved recloser is proposed in EP-A-1,017,142, which describes a recloser formed from a vacuum switch contained within a solid dielectric polymeric insulation material. The vacuum switch and the polymeric isolation material are enclosed within an air filled housing.

[0008] Whilst the solid dielectric overcomes the problem of using hazardous dielectric, such as oil or gas, a number of drawbacks still exist.

[0009] In particular, if an arc fault occurs within the switching element, the energy released will typically cause rapid heating and therefore rapid expansion of air within the housing. Such rapid expansion is likely to cause the housing to fail at its weakest point, thereby releasing superheated air in to the surrounding environment. As the weakest point in the housing is typically the fastened base plate, the occurrence of an arc fault will typically result in superheated air being expelled in a downward direction. In the event that an operator is in the region of the switching device this can result in serious injury to the operator. An allied problem is the burning caused by direct contact of the electrical arc with internal components of the recloser including the walls of the housing and consequent risk of melting and/or burn-through caused by elevated temperatures of the associated high energy plasma.

[00010] AU 2003244542 provides an improved recloser with a vent through which pressurized fluid in the housing can be vented to maintain the integrity of the housing.

[00011] The preferred embodiment of the present invention provides further improvements to the recloser of AU 2003244542 which, in turn, is incorporated herein by reference.

SUMMARY OF THE INVENTION

[00012] According to one aspect of the present invention, there is provided a recloser for use in an electrical circuit, the recloser including: a housing formed of one or more housing panels; and one or more reinforcement panels for reinforcing said housing panels, wherein the reinforcement panels are mounted internal to the housing and in facing relation to said housing panels to shield the housing panels from damage by internal electrical arcing.

[00013] The reinforcement panels may be mounted to the ends, sides, bottom and/or roof of the housing and arranged to impede the internal electrical arc from contacting the housing panels. The reinforcement panels may be removably fastened, for example bolted, to respective housing panels.

[00014] The recloser may further include an internal wall defining a space for passage of fluid moving toward a vent in the housing. The internal wall may form part of a bracket through which one or more poles of a recloser switch extend.

[00015] The recloser may further include one or more reinforcement ribs for reinforcing respective corners of the housing. Preferably, the ribs are curved. The ribs may extend from a panel which is fastened relative to the housing.

[00016] According to another aspect of the present invention, there is provided a recloser including: a housing; and a wall for locating within the housing and defining a space through which fluid moving toward a vent in the housing can pass.

[00017] According to another aspect of the present invention, there is provided a wall for locating within a housing of a recloser and defining a space for passage of fluid moving toward a vent in the housing.

[00018] According to another aspect of the present invention, there is provided a recloser including: a housing; and one or more reinforcement members for reinforcing respective corners of the housing.

[00019] According to another aspect of the present invention, there is provided a panel for mounting to a housing of a recloser, the panel including: one or more reinforcement members for reinforcing respective corners of the housing.

[0019A] According to a further aspect of the invention, there is provided a method of reinforcing an eiectrical circuit recloser housing formed from one or more panels against damage by electrical arcing, the method comprising the steps of: providing one or more reinforcement panels for reinforcing said housing panels; mounting the reinforcement panels internal to the housing and in facing relation to said housing panels; wherein, in use, the mounted reinforcement panels shield the housing panels from damage by internal electrical arcing.

[00020] Any of the features described herein can be combined in any combination with any one or more of the other features described herein within the scope of the invention.

BRIEF DESCRIPTION OF THE DRAWINGS

[00021] Preferred features, embodiments and variations of the invention may be discerned from the following Detailed Description which provides sufficient information for those skilled in the art to perform the invention. The Detailed Description is not to be regarded as limiting the scope of the preceding Summary of the Invention in any way. The Detailed Description will make reference to a number of drawings as follows: [00022] Figure 1a is a plan view of a recloser in accordance with an embodiment of the present invention; [00023] Figure 1 b is an end view of the recloser of Figure 1 a; [00024] Figure 2a is an end view of a recloser housing with reinforcement panels in accordance with an embodiment of the present invention; [00025] Figure 2b is a bottom view of the recloser housing of Figure 2a; [00026] Figure 2c is a side view of the recloser housing of Figure 2a; [00027] Figure 3 is a perspective view of a pole mounting bracket of the housing of Figure 2a; [00028] Figure 4a is a bottom view of a base panel for mounting to the housing of Figure 1; and [00029] Figure 4b is a side sectional view of the base panel sectioned though line ΛΑ in Figure 4a.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

[00030] According to an embodiment of the present invention, there is provided a recloser 100 as shown in Figure 1. The recloser 100 includes a housing 102 formed of generally planar panels, and a recloser switch having three sets of bushings 104 extending though the housing 102. The recloser 100 includes several features described in detail below which protect the housing 102 from adverse effects of internal arcing. The recloser 100 was successful type tested at 12.5kA for 1 second (which is 5 times the standards requirements in terms of duration).

[00031] Turning to Figure 2, the housing 102 includes three reinforcement panels 200a, 200b, 200c for reinforcing respective end, bottom and side roof panels 202a, 202b, 202c of the housing 102. The reinforcement panels 202 are mounted with bolts internal to the housing 200. The housing 102 is formed from 1.5mm stainless steel.

Each reinforcement panel 200 is sized to cover substantially the whole internal face of a respective housing panel 202 and formed from 2mm mild steel to thereby act as an electrical shield to impede the arc from reaching the housing 102 within a specified time. Whilst the interna! reinforcement panels 200 can suffer damage from the effects of arcing and associated burning upon contact by high temperature plasma, the panels 202 of housing 102 remain comparatively intact and in one piece.

[00032] Turning to Figure 3, the recloser 100 further includes a gang plate bracket 300 defining apertures 302 through which respective poles extend, down from bushings 104. The bracket 300 includes an internal wall 304 of the housing 102. The wall 304 defines an aperture space 306 through which pressurized fluid can move from the arc source and toward a vent in the housing 102. The aperture space 306 advantageously permits air flow during arcing which is otherwise restricted if the wall 304 is solid. Whilst aperture 306 is placed between the vent and the arc source, additional apertures 308, 310 also assist with internal airflow.

[00033] Turning to Figure 4, a base panel 400 is provided for mounting with fasteners (e.g. bolts) relative to the underside of the housing 102. The panel 400 includes three protruding reinforcement ribs 402a, 402b, 402c for reinforcing respective corners of the housing 102. Each rib 402 extends from a base plate 404, is curved, and engages with the underside of the housing 102. Reinforcing the housing corners in this manner distributes stresses and impedes the corners from rupturing owing to a rise in internal fluid pressure resulting from electrical arcing.

[00034] A person skilled in the art will appreciate that many embodiments and variations can be made without departing from the ambit of the present invention.

[00035] In compliance with the statute, the invention has been described in language more or less specific to structural features or methodical steps. It is to be understood that the invention is not limited to specific features or steps shown or described since the means herein described comprises preferred forms of putting the invention into effect.

[00036] Reference throughout this specification to ‘one embodiment’ or ‘an embodiment’ means that a particular feature, structure, or characteristic described in connection with the embodiment is included in at least one embodiment of the present invention. Thus, the appearance of the phrases ‘in one embodiment’ or ‘in an embodiment’ in various places throughout this specification are not necessarily all referring to the same embodiment. Furthermore, the particular features, structures, or characteristics may be combined in any suitable manner in one or more combinations.

Claims

The claims defining the invention are as follows:

1. A recloser for use in an electrical circuit, the recloser including: a housing formed of one or more housing panels; and one or more reinforcement panels for reinforcing said one or more housing panels, wherein the reinforcement panels are mounted internal to the housing and in facing relation to said housing panels to shield the housing panels from damage by internal electrical arcing.
2. A recloser as claimed in claim 1, wherein the reinforcement panels are mounted to the ends, sides, bottom and/or roof of the housing and arranged to impede the internal electrical arc from contacting the housing panels.
3. A recloser as claimed in any one of the preceding claims, wherein the reinforcement panels are fastened to respective housing panels.
4. A recloser as claimed in any one of the preceding claims, further including an internal wall defining a space for passage of fluid moving toward a vent in the housing.
5. A recloser as claimed in claim 4, wherein the internal wall forms part of a bracket through which one or more poles of a recloser switch extend.
6. A recloser as claimed in any one of the preceding claims, further including one or more reinforcement ribs for reinforcing respective corners of the housing.
7. A recloser as claimed in claim 6, wherein the reinforcement ribs are curved.
8. A recloser as claimed in either claim 6 or claim 7, wherein the reinforcement ribs extend from a panel which is fastened relative to the housing.
9. A recloser as claimed in claim 3 wherein the reinforcement panels are removably fastened to said housing panels.
10. A method of reinforcing an electrical recloser housing formed from one or more housing panels against damage by electrical arcing, the method including the steps of: providing one or more reinforcement panels for reinforcing said one or more housing panels; mounting the reinforcement panels internal to the housing and in facing relation to said housing panels; whereby, in use, the mounted reinforcement panels shield the housing panels from damage by internal electrical arcing.
11. The reinforcing method of claim 10 wherein the mounting step includes mounting the reinforcement panels to the ends, sides, bottom and/or roof of the housing and arranging the reinforcement panels to impede the internal electrical arc from contacting the housing panels.
12. The reinforcing method of either claim 10 or claim 11 wherein the mounting step includes fastening the reinforcement panels to said one or more housing panels.
13. The reinforcing method of claim 12 wherein the mounting step further includes removably fastening the reinforcement panels to respective housing panels.
14. The reinforcing method of any one of claims 10 to 13 further including provision of one or more reinforcement ribs for reinforcing respective corners of the housing.
15. The reinforcing method of claim 14, wherein the reinforcement ribs are curved.
16. The reinforcing method of either claim 14 or claim 15, wherein the reinforcement ribs extend from a panel that is fastened relative to the housing.