CA1258505A - Insulating support column with operating member - Google Patents

Abstract

ABSTRACT

An insulating support column is provided for driving interrupting units and includes an insulator having a longitudinal bore extending therethrough, a trans-lational operating member extending through and outside of both ends of the insu-lator, and sealing arrangements between the operating member and the insulator to retain insulating material within the insulator and to seal the bore from the external environment. The insulating support column is disposed substantially vertically during operation to drive the interrupting unit. The operating member includes a first portion of insulative material and metallic portions that are affixed at each end of the first portion. The lower metallic end portion of the operating member includes a connector that is driven by a power train and the upper metallic end portion includes a connector that is connected to drive an interrupting unit. An end fitting is affixed to each end of the insulator. Each of the end fittings includes a central bore and a sealing arrangement within the bore. The upper sealing arrange-ment operates with respect to the first, insulative portion of the operating member and the lower sealing arrangement operates with respect to the lower metallic portion. The lower sealing arrangement is arranged with respect to the mounting surface such that the lower metallic end portion of the operating member does not extend into the insulator beyond the end fitting. The dielectric withstand capability of the insulating support column is not reduced by the presence of the operating member for any position of the operating member along its translational path.
Accordingly, if excessive voltage should cause an electrical discharge to occur between the end fittings of the insulator, the flashover will take place external to the insulator.

Description

5 ~ A
SC-51gS-C

INSULATING SUPPC)RT COLUMN WlTH OPERATING MEMBER

Cross Reference to Related Applications This application is directed to an improved insulating support column including a translational operating member disposed therethrough as disclosed in commonly-assigned Canadian application Serial Nos. 485,637, 485,631 (now Canadian Patent No.
1,243,086), and 485,639 filed on June 27, 1985 in the names of L-V- Chabala et al.

Field of the Invenffon The present invention relate~ generally to the fiedd of insulating support c~lumns for driving interrupffng units o~ high voltage circ~t protecffonarrangements and more particularly to sn improved insulating support column including a tran~lationat operaffng member that elctends a~ially through and outside of both ends of the ins~ating support column.
Description of the Re~ated Art Various drive linkage ~rrangements ~re known for high-voltage circuit breake~; and for highvoltage interrupffng Ullits. One category of drive linkage arrangement include insulating columns with pressurized gas or oil that carry trans-laffonal operaffng members that are driven in various manners; commorly by pivotal linkage members that enter the sealed, insulated column through an "O" ring seal or the like. Other types of dfive linkage arrangements in this category can be described as using a crank with a rotary shaft seal; or example as shown in Sprecher ~ Schuh 30 publications 42Ft enfftled '~IGF 100 SF6 Outdoor Circuit Breaker Seriesn, 41F5 entitled "HP506-A New Eîficient Circuit E~reaker ~or Distribution Switchgear", 4120 ~.~e lZ5~3~5~)5 entitled "Low Oil Content Circuit Breaker for 52. . . 72.5kV Indoor Installation"
(October 1975), 4150 entitled "Low Oil Content Circuit Breaker for Outdoor Stations 10 . . . 82.5kV" tDecember 1977), and Sprecher News, March 1980. Another type ofdrive linkage arrangement in this category utilizes a pneumatically- or mechanically-driven operating rod that extends into a pressurized column; seals being provided between the translational operating rod and the pressurized column. Arrangementsof this type are shown in ASEA Pamphlet LA36-102E entitled "SF6 Circuit-Breaker Type HPL", AEG brochure entitled '~F6 Circuit-Breaker for Rated Voltages of 72.5kV up to 765kV", and BBC Brown, Boveri ~ Company Publication No. CH-A083 10 322 E entitled "SF6 Circuit-Breaker Type ELF and Type ELI".

Another drive linkage arrangement described in U.S. Patent No.
3,566,055 and IEEE paper C 74 17~7 provides for rotation of an insulator 31 ~FIGS. 3 and 4) to operate a T-shaped movable switch component 30. The drive linkage arrangement also provides for rotation of an insulated rotary shaft 51 (FIGS. S and ~
11) that extends upwardly through the insulator 31 into the center section 33. The rotation of the insulated shaft 51 operates mechansims that in turn operate the interrupting device 40 and a bypass device 44. The shaft 51 and the insulator 31 are rotated in timed relationship. Neither the dielectric withstand capability nor the 20 insulating properties of the insulator 31 are addressed. Although the shaft 51 is referred to as an insulated shaft, the shaft 51 is apparently metallic and no pro-visions are disclosed for dielectric consideration of the overall movable switchcomponent 30 and no seals are disclosed between the insulator 31 and the shaft 51.

While these arrangements may be generally suitable for their intended purposes, none of these arrangements provides translational movement of an operating member that extends out the top of an insulating support column, that is driven below the insulating support column, and that includes metallic end portions.

()5 SUMMAR~' OF THE INVENTION

Accordingly, it is a principal object of the present invention to provide Qn insulating support column that includes a translational operating member thatextends through and outside both ends of an insulator and that also extends through one or more sealing arrangements between the operating member and the insulator,the translational operating member having a first portion of insulative material and metallic end portions; the insulating support column having a minimum overall height above a lower mounting surface, exhibiting a dielectric withstand capability that is 10 not degraded by the presence of the operating member, and ensuring that any electrical flashover that might occur will extend and take place external to theinsulator.

It is another object of the present invention to provide a sealed, insu-lating support column of overall minimum height above a mounting surface and having preferred dielectric withstand capabilities, the insulating support column including a translational operating member that extends through and outside bothends of an insulator, the operating member including a first, insulative portion and metallic end portions; the operating member at its upper end moving through seals in 20 contact with the insulating portion of the operating member, and the operating member at its lower end moving through seals in contact with the metallic end portion of the operating member.

Briefly, these and other objects and advantages of the present inven-tion are efficiently achieved by providing an insulating support column for driving interrupting units and including an insulator having a longitudinal bore extending therethrough, a translational operating member extending through and outside of both ends of the insulator, and sealing arrangements between the operating member and the insulator to retain insulating material within the insulator and to seal the 30 bore from the external environment. The insulating support column is disposedsubstantially vertically during operation to drive the interrupting unit. The operating member includes a first portion of insulative material and metallic portions that are affixed at each end of the first portion. The lower metallic end portion of the lZ5~35()5 operating member includes a connector that is driven by a power train and the upper metallic end portion includes a connector that is connected to drive an interrupting unit. An end fitting is affixed to each end of the insulator. Each of the end fittings includes a central bore and a sealing arrangement within the bore. The upper sealing arrangement operates with respect to the first, insulative portion of the operating member and the lower sealing arrangement operates with respect to the lower metallic portion. The lower sealing arrangement is arranged with respect to the mounting surface such that the lower metallic end portion of the operating member does not extend into the insulator beyond the end fitting. The dielectric withstflnd 10 capability of the insulating support column is not reduced by the presence of the operating member for any position of the operating member along its translational path. Accordingly, if excessive voltage should cause an electrical discharge to occur between the end fittings of the insulator, the flashover will take place external to the insulator.

BRIEF DESCRIPTION OF THE DRAWING

The invention both as to its organization and method of operation, together with further objects and advantages thereof, will best be understood by20 reference to the specification taken in conjunction with the accompanying drawing in which:

FIG. 1 is an elevational view partly in section of the insulating support column of the present invention;

FIGS. 2-4 are diagramatic representations of insulating support columns of various configurations to illustrate the considerations that are addressed by the present invention; and FIG. 5 is a diagramatic representation of the insulating support column of the present invention for comparison with the arrangements of FIGS. 2-4.

1~5~t~()5 DETAILED DESCRIPTION

Referring now to FIG. 1, the insulating support column 10 of the present invention includes an elongated operating member 12 that is disposed through a longitudinally extending bore 14 of an insulator 16 for translation or movement along a predetermined path, generally referred to at 18. The path 18 may also bereferred to ~s a stroke, the extent of the stroke being illustrated at 19. The opers-ting member 12 also extends out both ends of the insulator 16. An upper flange 20 is affixed to the upper end of the insulator 16 and a lower flange 22 is affixed to the 10 lower end of the insulator 16. An upper end-fitting 24 is affixed to the upper flange 20 and a lower end-fitting 26 is affixed to the lower flange 22. The upper and lower en~fittings 24 and 26 which may also be referred to as seal housings include respe~
tive bores 28,30 for passage of the operating member 12. The lower end-fitting 26 includes suitable seals and bushings at 34 to guide the operating member 12, to seal the bore 14 from the external environment, and to prevent the leakage of insulating material or fluid from the column; the insulating material being referred to at 32 within the bore 14. The upper end-fitting 24 also includes suitable seals and bushings at 36 to guide the operating member 12 and to provide a seal around the operating member 12. In a preferred arrangement, the upper and lower flanges 20 and 22 and20 the upper and lower end-fittings 24 and 26 are fabricated from metal to provide the desired strength. In a preferred embodiment, the upper end-fitting 24 includes an aerator of the type disclosed in U.S. Patent No. 3,696,729. In a specific embodiment, the end-fitting and the flange are provided as a single component.

The operating member 12 includes a first portion 40 fabricated from an insulative material such as glass-reinforced polyester. In specific embodiments, the first portion 40 is either tubular or is a solid rod. The operating member 12 also includes an upper portion 42 fabricated from metal and attached to the upper end of the first portion 40. The operating member 12 also includes a lower portion 44 30 fabricated from metal and attached to the lower end of the first portion 40. The upper portion 42 includes a connector 43 and the lower portion 44 includes a connector 46. In a specific embodiment, the metal portion 42 is secured by threading engagement into the first portion 40. Similarly, in a specific embodiment, the lower 1~5~35()5 portion 44 is secured to the first portion 40 by threading engagement of the fiÆt portion 40 between the lower portion 44.

With the insulating support column 10 mounted vertically, as shown in FIG. 1, gravity slso acts on the ir~ulaffng material 32 between the seals at 34 and the operating member 12. Thus, the seal at the lower end of the insulating support column lû must provide the necessary sealing characteristics in both a dynamic and ststic sense. The sePl at the upper end of the irsulating support column 10 as defined between the se~ls at 36 and the operating member 12 is less eritical than the 10 seal at the lower end of the irsulating support column 10 and is required or~y to present the loss of ir~ulating material 32 during shipment or ~torage as well as to sePl the bore 14 from the external environment; the upper se 1 does not ha~e anystringent, criffc~l dynami~ or static requirements during the actuPl service andoperation of the inslilating support column 10.

The lower portion 44 of the operating member 12 is in contact with the seals at 34 throughout the predetermined path and is required to present a smooth and accurate surface fos engagement with the seals at 34 to provide effective, desired se~ling. ~or uses such as those discussed in the aforementioned co-pending 20 applications, the operating member 12 is sub~ected to suddenly applied tension and compression loads and reciprocates through a definite stroke or predetermined path of travel as indicated at 18. The connectors 43 and 46 ere desirable and necessary for connection to driving and driven members. For example, the lower connector 46 is driven over the trQn~a'donal path 18 by connecffon to a power train and the upper connector 43 is connected to drive an interrupter operator member of an interrupting unit as discussed in more detail in C~nadian application Serial Nos. 485,639 and485,637~ Iiled on June 27, 1985 in the names of Chabala, et al, to which reference may be made. Additionally, the insulating material 32 that is preferred for various uses of the insulating support column 10 is disclosed and claimed in Canadian application Serial No. 485,631 (now Canadian Patent No.
1,243,086), filed on June 27, 1985 in the names of Chabala, et al, to which reference may be made.

8~i()5 Since the ins~ating support column 10 serves as an insulator in its various applications in circuit protection device config~lraffons, the insulating support column 10 must meet dielectric requirements including impulse voltage ratings and 60 Hz voltage withstand capabilities; the magnitudes of which depend on the voltage ratings of the specific configuration~ In various circuit protection device configurations in which the insulaffng support column finds application and use, it is desirable to minimize the overall height of the insulating support column 10 above a mounffng surface 48 of the lower end-fitting 26 and also to appro~mate the height of standard insulators of corresponding rated voltage. Accordingly, it is desirable to 10 minimize the overall height of the insulaffng support column 10 without reducing or degrading the dielectric withstand capability of the insulating support column 10 due to the presence and translation of the operaffng member 12 along with any metallic portions or connectors of the operating member 12. Accordingly, any flashover induced by various testing or abnormally high service voltages, if such should occur, should take place outside the insulator 16. Thus, it is desirable to avoid encroach-ment by the metal portions of the operating member 12 into the dielectric gap of the insulating support column 10 such thflt movement of the operating member 12 overthe path 18 does not degrade the dielectric withstand capability of the assembled insulating support column 10.
Referring now to FIG. 2, graphically depicted is an insulating support column 120 having a different configuration than that of the insulating support column 10 of the present invention as illustrated in FIG. 1. In FIG. 2, the operating member 121 includes first portion 122 having a diameter Dl that is selected for buclcling strength. The upper and lower metallic portions 123 and 124 are fabricated and selected for adequate strength and simple mechanical considerations wit respective dimensions D3 and D2 which are significantly less than Dl. When the operaffng member 121 is at the uppermost position of its translational path as shown in FIG. 2, the dimension P defines the penetration into the column of the lower 30 metallic portion 124 beyond the height H of the lower nange 22. Similarly, P' repre-sents the penetration into the column of the upper metallic portion 123 when theoperaffng member 121 is moved to the lowermost position of its translational travel.

, ... . . . .

~5~3505 In FIG. 3, ~ere i~ ~lustrPted An operating member 131 having metal1ic portions 133 and 134 of similar lengtl~ to those o~ FIG. 2, but of equ~l diameter to the first, centr~l section 132 o~ the opersting member 131 such that Dl = D2 ~ D3.
The uniform diameter of the operating member 131 i~ desirable to prevent churning acffon of the insulaeing material within the column which may be caused by the tran~lationaI movement of sn opers~ng membe~ that ha~ a no~uniform diameter such as the operating member 121 of FIG. 2. However, the metallic portions 133 and 134 penetrate within the column beyond the upper and lower flanges to the same extent as shown in FIG.

2; the arrangement in FIG. 3 beingillustrated with the operating 10 member 131 at the uppermost point of travel of its translational movement, In FIG. 4, the position of the operating member 131 is illustrated at the lowest position with the maximum penetration of the portion 133 within the column. With the arrangements of FIGS. 2-4, the axial positioning of the metallic end portions of the operating member beyond the flanges is undesirable in that any electrical flashovers that are induced might not be constrained to take place external to the insulator. For example, internal dielectric breakdown or flashover can permanently damage or degrade the insulating material 32 and the operating member 12, and may cause incidental degradation or reduction of the withstand capacity.
Considering the ~eatures OI the pr~nt invention o~ the in~ulating support column 10 of FIG. 1 and r~erring now additiona31y to FIG. S, the lengtl~ of the metallic end portior~ 143,144 o~ the operating member 141 are limited so as not to extend beyond the end n~ge~ snd into the insulstor 145 to ensure that any n~sh-over that occurs will tske plsce externAl to the insulator 145. The ingulating support column 140 of ~IG. 5 and the in~ulaffng support column 10 of FIG~ 1 achieve the features of the present invention by providing a minimal-length, meta~ic upper porffon 143 and a metallic lower portion 144 that does not extend into the insulator 145 beyond the depth o~ the lower nange 22 such that the ~ t portion 142 o~ the operaffng member 141 that is fabrieated ~rom insulative material is greater in length 8~ compared to that of the operating members of FIGS. 2-4; the increase in length being defined a~ depicted by the dimen~ion lS0 at the upper end and by the dimen~ion t)S

152 at the lower end of the column 140. Accordingly, the length of the first portion 142 is at least equal to or greater in length than the sum of the separation between the upper end fitting 24 and the lower end fitting 26 and the length 19 of the stroke or predetermined path of translation.

In aeeord~nce with the pre~ent invention, the ir~ating portion 142 of the operaffng member 141 operate~ in the upper se~ 3fi oP the upper end-fitffng 24 such that the met~c upper porSion 143 never extend~ beyond the fl~nge 20 and, in~act, never even e~ctends to the be~ ng oi the nang~ 20 since the porffon 143 does 10 not extend beyond the seQls 36 at any point o~ the translatlonRI path ~.e. the upper portfon 1~3 never mo~res below the posifforl 151 OI ~IG. 5). Purther, the metallic, upper portion 143 o~ the operaffng member 141 doe~ not de~rade the dielectric withst~nd capability o~ the ir~affng support column 140. SimiIsrly, the low location o~ the Selll9 34, vrith respect to the nange 22 ~nd the mounting sur~ace 48, provides for continuous enBgement Or the seal~ 34 by the metallic~ lower portion144 o~ the operating member 141 throughout the truslational path while æl50 eliminsffng ~y extension :into the irsu~ator 145 o~ the metallic, lower portion 144 abov~ the e~tent oi the n~g~ 22; the ~arthest e~tendon of travel o~ the metallic, lower portion 144 being depfc~ed at 160. Thu~, the in~ula'dng support colwnn 140 o~
2 0 FIG. S and the ins~at{ng ~upport column 1 0 oi FIG. 1 provide appropriate sealing fQr the ir~ulatlng material 32 while mainteining a de~ired dielectric withstand capQbility without degrad~tion due to the translatlon~l operating member 141 that includes metallic end portionY. Purther, these desirable chQracteristics ere schieved without an incre~se in the height o~ the insulaffng support column 10 above the mountingsur~ace 48; the lower seQls 34 being ~!apable o~ being repo~dffoned as shown in FIG. 5 with respect to that o~ the arrangements in PIGS. 2-4 while the mounting sur~ace 48 for the insulating support column remains the same. As can be seen from FIG. 5, the seals 34 are positioned below the top end of the flange 22 by a distance that is approximately equal to the length 19 of the predetermined path.

1~5~5~)5 The operating member 141 o~ the ins~Qting support column 140 o~ PIG.
5 depic~ a speci~le embodiment o~ the pre~ent inven'don wherein the operating member 141 includes a uniform cro~ ~ecffon while the operating member 12 o~ the insulsting support column 10 o~ FIG. 1 depic~ a sp~eifle embodiment wherein the opersffng member 12 is of non-uniiorm ~ ecffon. In a ~peeiflc embodiment where the end iitting~ 24 and 2~ ~ ins~ative, the ~eal~ 34 and 3B can be posiffoned cla~er to the bore 114 but thes~ podtlon3 must o~ course be consbtent with the dedred po~i'dor~ o~ the m~at~lic end portions 143,144 or 42,44. While the opera'dng member 12 of the irsldating ~upport ~olumn 10 o~ PIG. 1 i~ cussed a~ being 10 ~!apable of tru~ ffoR with re~pect to the insulator 1~, in a ~pecific embodiment, the operating member 12 is also capable of rotational movement with respect to the insulator i6 as dise1Osed in the aforementioned application Serisl No. 485,639.

While there have been illustrated and described various embodiment~ of the present invenffon, it will be apparent that various ~hanges and modifications will occur to those sldlled in the art. It is intended in the appended claims to cover all such changes and modificaffons as fall within the true spirit ~nd scope of the present invention.

Claims (13)

The embodiments of the invention in which an exclusive property or privilege is claimed are defined as follows:

1. An insulating support column comprising:
an elongated insulator having a longitudinal bore extending therethrough;
upper and lower fittings affixed to said insulator, each of said fittings including a central bore;
an elongated operating member extending through said bore of said insulator and through said upper and lower fittings, said elongated operating member including a first portion having a predeter-mined length and being fabricated from insulative material, said elongated operating member further including metallic end portions affixed at the ends of said first portion, said elongated operating member being arranged for translation over a predetermined longitudinal path with respect to said insulator, said first portion of said elongated operating member being greater in length than the sum of the separation between said upper and lower fittings and the length of said predetermined longitudinal path; and a lower sealing arrangement provided within the bore of said lower fitting for cooperation with said elongated operating member, said lower sealing arrangement being carried within said bore of said lower fitting, the longitudinal positioning of said lower fitting and said elongated operating member being determined along with the length of said lower metallic end portion so that said lower sealing arrangement acts on said lower metallic end portion throughout said predetermined longitudinal path and such that the dielectric withstand capability of the insulating support column is not degraded by said elongated operating member for any position of said elongated operating member along said predetermined longitudinal path.

2. The insulating support column of claim 1 further comprising insulating material disposed within the bore of said insulator.

3. The insulating support column of claim 2 further comprising an upper sealing arrangement provided within the bore of said upper fitting for cooperation with said elongated operating member, said upper sealing arrangement and said elongated operating member being longitudi-nally positioned so that said upper sealing arrangement acts on said first portion of said elongated operating member throughout said predeter-mined longitudinal path.

4. The insulating support column of claim 3 wherein said longitudinal positioning of said upper sealing arrangement with respect to said lower fitting is the minimum distance that is consistent with the separation between said upper and lower fittings.

5. The insulating support column of claim 3 wherein said lower fitting defines a reference plane for the mounting of the insulating support column, and wherein the top of said lower sealing arrangement is longitudinally positioned below said top end of said lower fitting by a distance that is approximately equal to the length of said predetermined longitudinal path.

6. The insulating support column of claim 3 wherein said elongated operating member is longitudinally positioned in said insulator such that said lower metallic end portion of said elongated operating member does not extend into said insulator beyond the extent of said lower fitting at any point of said predetermined longitudinal path, said lower sealing arrangement being longitudinally positioned such that it is below the top end of said lower metallic end portion of said elongated operating member when said elongated operating member is at the lowermost position of said predetermined longitudinal path.

7. The insulating support column of claim 1 wherein said elongated operating member is tubular.

8. The insulating support column of claim 1 wherein said elongated operating member is a solid rod.

9. The insulating support column of claim 1 wherein the cross sections of said first portion and said lower metallic end portion of said elongated operating member are of substantially identical shape and dimensions.

10. The insulating support column of claim 1 wherein said elongated operating member extends out both ends of said insulator and said upper and lower fittings throughout said predetermined longitudinal path.

11. The insulating support column of claim 1 wherein said upper and lower fittings are metallic.

12. An insulating support column comprising:
an elongated insulator having a longitudinal bore extending therethrough;
upper and lower fittings affixed to said insulator, each of said fittings including a central bore and a sealing arrangement disposed within said bore; and an elongated operating member extending through said bore of said insulator and said bores of said upper and lower fittings, said elongated operating member being arranged for translation over a predeter-mined longitudinal path with respect to said insulator, said sealing arrangements cooperating in sealing engagement with said elongated operating member throughout said predetermined longitudinal path, said elongated operating member including a first portion having a predeter-mined length and being fabricated from insulative material, said elongated operating member further including metallic end portions affixed at the ends of said first portion, the longitudinal position of said sealing arrangements of said upper and lower fittings and said length and longitudinal positioning of said first portion and said metallic end portions being defined such that said sealing arrangement of said upper fitting engages said first portion of said elongated operating member throughout said predetermined longitudinal path, such that said sealing arrangement of said lower fitting engages said lower metallic end portion throughout said predetermined longitudinal path, and such that said metallic end portions never extend longitudinally into said insulator past the extent of said upper and lower fittings.

13. The insulating support column of claim 12 wherein said upper and lower fittings are metallic.