CA2143580A1 - Method and apparatus for the substantial elimination of oxidation in transformer insulating oils - Google Patents
Method and apparatus for the substantial elimination of oxidation in transformer insulating oilsInfo
- Publication number
- CA2143580A1 CA2143580A1 CA 2143580 CA2143580A CA2143580A1 CA 2143580 A1 CA2143580 A1 CA 2143580A1 CA 2143580 CA2143580 CA 2143580 CA 2143580 A CA2143580 A CA 2143580A CA 2143580 A1 CA2143580 A1 CA 2143580A1
- Authority
- CA
- Canada
- Prior art keywords
- inert gas
- expansion chamber
- oxidation
- continuous flow
- oil
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Abandoned
Links
Landscapes
- Organic Insulating Materials (AREA)
Abstract
Intimate contact between transformer insulating oils and air results in the oxidation of the oils as well as contamination from moisture and other airborne contaminants, thus reducing the useful lifespan of the oil and increasing maintenance costs. Amethod and apparatus for the substantial elimination of such oxidation is comprised of an inert gas generator mounted in close proximity to a power transformer con-tainment tank and connected to the tank expansion chamber via at least oneconduit. A continuous flow of substantially moisture free inert gas, such as nitrogen, is generated at atmospheric pressure and introduced at one end of the expansion chamber via the conduit. The inert gas flows across the surface of a head of oil contained in the expansion chamber and is evacuated at the opposite end of the expansion chamber where it is dissipated in the surrounding atmoshere.
The continuous flow of inert gas across the oil surface displaces and eliminates all air from intimate contact with the oil, thus substantially eliminating the cause of oil oxidation.
The continuous flow of inert gas across the oil surface displaces and eliminates all air from intimate contact with the oil, thus substantially eliminating the cause of oil oxidation.
Description
21~35~0 This invention relates to the field of dielectric fluids as used in freely breathing, electrical power l,d,lsrur"~ers, more particularly to a method and appardt-Js to sub-stantially eliminate fluid oxidation.
It is well known, although perhaps not so well understood, that inlimale conlac~05 between power tran~rur",er insulating oils and air results in oxidation and degrada-tion of the oil by absor~Jlion of air borne conlaminanls such as moisture.
It is not surprising, then, that considerable inventive ingenuity has been applied to the resolution of this problem, resulting in the design of several transformer oil containment systems specifically intended to reduce or eliminale entirely, inlimale 10 contact between the oil and the air.
Such systems range from the relatively simple, e.g., a sealed tank containing, in addition to the oil, an inert gas under pressure which effectively excludes air from the system, to the moderately complex conservator/diaphragm systems which, as the name implies, utilizes a flexible bladder capable of following the expansion and con-15 traction of the oil.
An example of a sealed tank system is exemplified in Soviet patent number1334196 which issued to Bratus et al in August, 1987 and wherein is disclosed a tank containing dielectric fluid (transformer oil) with the cover of the tank separated from the mirror surface of the fluid by an inert gas (nitrogen~ introduced and captured 20 under pressure.
Another example of a sealed tank system may be found in South African patent number 7701020 which issued to Lampe et al in November, 1977 and wherein is disclosed a method of operating a power transformer within the confines of an oil filled sealed tank with the oxygen content of the oil maintained at less than 300 ppm 25 by continuously de~Assing the oil during operation of the transformer.
Sealed systems, not unlike those described above, are a widely accepted solu-tion to the problem of oil oxidation when applied to relatively small distribution trans-~ 2143~0 formers but are gener~lly regarcled as u"acceptable for use with the mostly freelybreathing, large, very high voltage, power l,~"~rur",ers.
Since the electrical safety of such very high voltage transformers is para",ount, the mechanical systems utilizing sealed tanks or collapsible bladders are of limited os use beG~use of their negative impact on the reliable Gperability of the primary safety device employed in such transformers, i.e., the pressure dirrere"lial responsiveBucholtz relay.
At present, then, it is normal practice to sacrifice the integrity of the insulating oil in favour of electrical safety. Of course, oil inlended for use in power tran~r."",er:j 10 may be, and commonly is, pre-treated with antioxidant in an ~llelllpt to retard the oxidation process which treatment, while undoubtedly an improvement over nothingat all, nevertheless serves only to slow the oxidation process.
The addition of antioxidant - usually in the form of Ditertiary Butyl Para-Cresol and Ditertiary Butyl Phenol - does little or nothing to prevent the occurrence of oxida-15 tion in the first place.
The methods for the prevention of oxidation of transformer insulating oilsheretobefore known suffer, then, from the following sllo, lcor"ings:
a) they require the use of a gas tight, sealed transformer tank thus increasing manu-facturing costs and i,nposi"g a relatively high quality control regime;
20 b) inert gas introduced to the transformer tank under pressure negatively impacts the operability of existing and commonly employed electrical safety devices such as a Bucholtz relay; and c) pre-treatment of the oil with aromatic cor"pounds merely retards oil oxidation but does not prevent its occurrence.
It is an object of the present invention to provide an economically viable, simple, safe and efficient method and apparatus to substantially eliminate insulating oil decay caused by oxidation of the oil in the presence of air.
2143~80 a) to provide a method and apparal.ls to s~hsl~rllially elil"indle oxidation of trans-former insulating oils, thus increasing the useful lifespan of such oils and hence, reducing mainlenance costs to the operator;
b) to provide a melhocl and apparatus to sl ~hsl~"lially eliminate oxid~tion of trans-05 former insulating oils without adverse effects on the oper~bility of existing electrical safety devices cor"",o, lly used in conjunction with power lldnsrur",er~; and c) to provide a method and apparalus to 5~lhsl~nlially eliminate oxidation of trans-former insulating oils which s~lhst~ntially removes the need for pre-treatment of such oils with antioxidant.
Further objects and advantages will become apparent from a consideration of the ensuing description and drawing wherein:
According to one aspect, then, the present invention is a method for the sub-stantial elimination of oxidation of dielectric fluid used in high voltage power trans-formers comprising the steps of:
15 generating a continuous flow of inert gas;
introducing said continuous flow of said inert gas to one end of an expansion chamber of said l,ansror"~ercontainmentvessel; and evacuating said continuous flow of said inert gas at an end of said expansion cham-ber opposite the end wherein the said continuous flow of said inert gas is introduced 20 so that said flow is across the surface of said dielectric fluid and displaces and elimi-nates any air in intimate conlact with said surface of said dielectric fluid.
According to another aspect, the present invention is an apparatus for the sub-stantial elimination of oxidation of dielectric fluid used in high voltage power trans-former comprising:
25 a dielectric fluid filled high voltage transformer containment vessel having an expan-sion chamber connected to an upper end of said containment vessel via a constricted channel, said expansion chamber containing a slight head of said dielectricfluid; and 21~35~0 means for gener~ g a continuous flow of inert gas at al"~ospheric pressure said means located in close proximity to said co"la..,ment vessel and connected by atleast one conduit to said ex~ansion chal,lber so that said continuous flow of said inert gas is introduced via said conduit into said expansion chamber at one end flows 05 across the surface of said ~ielectric fluid and is ev~cl l~ted at the other end of said expansion chamber.
The present invention is desclibed in further detail having rerere"ce to the ac-companying drawing in which;
Figure 1 is a schematic representation of the apparatus showing the flow of gas within a transformer tank expansion chamber.
Nitrogen 16 at aL",ospheric pressure is generaled in a nitrogen generdlor 10 of conventional design and known to those skilled in the art and conveyed to a trans-former tank 24 expansion char"ber 14 via conduit 12 where it enters to one side of the expansion chamber 14 at the top; fills the space between the inner top surface of the expansion chamber 14 and the surface of a transformer insulating oil 20.
The nitrogen 16 still at at",ospheric pressure is preferably eV~cll~te~l from the opposite side of the expansion chamber 14 and returned to the nitrogen generalor 10 via conduit 18.
Aller"alely the nitrogen 16 may be simply vented from the expansion chamber 14 at the opposite end of the chamber 14 from the inlet conduit 12 and dissipated in the surrounding atmosphere.
It will be understood that the flow of nitrogen 16 into and out of the expansionchamber 14 is continuous while the maintenance of the flow at atmospheric pressure ensures the unimpaired operability of a Bucholtz relay 22 in the event of electrical failure.
It will be seen then that the present invention offers a safe simple efficient and cost effective means for the substantial elimination of oxidation of transformer insulat-ing oils as commonly used in freely breathing high voltage power transformers byproviding within the transformer tank expansion chamber a continuous flow of inert ~ 21~3580 gas at atmospheric pressure across the surface of the transformer oil thereby dis-placing and eliminating air from inlimdle conlacL with the oil surface while leaving the operability of electrical safety devices unimpaired.
The description contained herein should not be construed as limiting the scope 05 of the invention but rather as an illusl~dlion of the presently prerer,ed embodiment.
Thus the scope of the invention should be dete""ined by the appended claims and their legal equivalent.
It is well known, although perhaps not so well understood, that inlimale conlac~05 between power tran~rur",er insulating oils and air results in oxidation and degrada-tion of the oil by absor~Jlion of air borne conlaminanls such as moisture.
It is not surprising, then, that considerable inventive ingenuity has been applied to the resolution of this problem, resulting in the design of several transformer oil containment systems specifically intended to reduce or eliminale entirely, inlimale 10 contact between the oil and the air.
Such systems range from the relatively simple, e.g., a sealed tank containing, in addition to the oil, an inert gas under pressure which effectively excludes air from the system, to the moderately complex conservator/diaphragm systems which, as the name implies, utilizes a flexible bladder capable of following the expansion and con-15 traction of the oil.
An example of a sealed tank system is exemplified in Soviet patent number1334196 which issued to Bratus et al in August, 1987 and wherein is disclosed a tank containing dielectric fluid (transformer oil) with the cover of the tank separated from the mirror surface of the fluid by an inert gas (nitrogen~ introduced and captured 20 under pressure.
Another example of a sealed tank system may be found in South African patent number 7701020 which issued to Lampe et al in November, 1977 and wherein is disclosed a method of operating a power transformer within the confines of an oil filled sealed tank with the oxygen content of the oil maintained at less than 300 ppm 25 by continuously de~Assing the oil during operation of the transformer.
Sealed systems, not unlike those described above, are a widely accepted solu-tion to the problem of oil oxidation when applied to relatively small distribution trans-~ 2143~0 formers but are gener~lly regarcled as u"acceptable for use with the mostly freelybreathing, large, very high voltage, power l,~"~rur",ers.
Since the electrical safety of such very high voltage transformers is para",ount, the mechanical systems utilizing sealed tanks or collapsible bladders are of limited os use beG~use of their negative impact on the reliable Gperability of the primary safety device employed in such transformers, i.e., the pressure dirrere"lial responsiveBucholtz relay.
At present, then, it is normal practice to sacrifice the integrity of the insulating oil in favour of electrical safety. Of course, oil inlended for use in power tran~r."",er:j 10 may be, and commonly is, pre-treated with antioxidant in an ~llelllpt to retard the oxidation process which treatment, while undoubtedly an improvement over nothingat all, nevertheless serves only to slow the oxidation process.
The addition of antioxidant - usually in the form of Ditertiary Butyl Para-Cresol and Ditertiary Butyl Phenol - does little or nothing to prevent the occurrence of oxida-15 tion in the first place.
The methods for the prevention of oxidation of transformer insulating oilsheretobefore known suffer, then, from the following sllo, lcor"ings:
a) they require the use of a gas tight, sealed transformer tank thus increasing manu-facturing costs and i,nposi"g a relatively high quality control regime;
20 b) inert gas introduced to the transformer tank under pressure negatively impacts the operability of existing and commonly employed electrical safety devices such as a Bucholtz relay; and c) pre-treatment of the oil with aromatic cor"pounds merely retards oil oxidation but does not prevent its occurrence.
It is an object of the present invention to provide an economically viable, simple, safe and efficient method and apparatus to substantially eliminate insulating oil decay caused by oxidation of the oil in the presence of air.
2143~80 a) to provide a method and apparal.ls to s~hsl~rllially elil"indle oxidation of trans-former insulating oils, thus increasing the useful lifespan of such oils and hence, reducing mainlenance costs to the operator;
b) to provide a melhocl and apparatus to sl ~hsl~"lially eliminate oxid~tion of trans-05 former insulating oils without adverse effects on the oper~bility of existing electrical safety devices cor"",o, lly used in conjunction with power lldnsrur",er~; and c) to provide a method and apparalus to 5~lhsl~nlially eliminate oxidation of trans-former insulating oils which s~lhst~ntially removes the need for pre-treatment of such oils with antioxidant.
Further objects and advantages will become apparent from a consideration of the ensuing description and drawing wherein:
According to one aspect, then, the present invention is a method for the sub-stantial elimination of oxidation of dielectric fluid used in high voltage power trans-formers comprising the steps of:
15 generating a continuous flow of inert gas;
introducing said continuous flow of said inert gas to one end of an expansion chamber of said l,ansror"~ercontainmentvessel; and evacuating said continuous flow of said inert gas at an end of said expansion cham-ber opposite the end wherein the said continuous flow of said inert gas is introduced 20 so that said flow is across the surface of said dielectric fluid and displaces and elimi-nates any air in intimate conlact with said surface of said dielectric fluid.
According to another aspect, the present invention is an apparatus for the sub-stantial elimination of oxidation of dielectric fluid used in high voltage power trans-former comprising:
25 a dielectric fluid filled high voltage transformer containment vessel having an expan-sion chamber connected to an upper end of said containment vessel via a constricted channel, said expansion chamber containing a slight head of said dielectricfluid; and 21~35~0 means for gener~ g a continuous flow of inert gas at al"~ospheric pressure said means located in close proximity to said co"la..,ment vessel and connected by atleast one conduit to said ex~ansion chal,lber so that said continuous flow of said inert gas is introduced via said conduit into said expansion chamber at one end flows 05 across the surface of said ~ielectric fluid and is ev~cl l~ted at the other end of said expansion chamber.
The present invention is desclibed in further detail having rerere"ce to the ac-companying drawing in which;
Figure 1 is a schematic representation of the apparatus showing the flow of gas within a transformer tank expansion chamber.
Nitrogen 16 at aL",ospheric pressure is generaled in a nitrogen generdlor 10 of conventional design and known to those skilled in the art and conveyed to a trans-former tank 24 expansion char"ber 14 via conduit 12 where it enters to one side of the expansion chamber 14 at the top; fills the space between the inner top surface of the expansion chamber 14 and the surface of a transformer insulating oil 20.
The nitrogen 16 still at at",ospheric pressure is preferably eV~cll~te~l from the opposite side of the expansion chamber 14 and returned to the nitrogen generalor 10 via conduit 18.
Aller"alely the nitrogen 16 may be simply vented from the expansion chamber 14 at the opposite end of the chamber 14 from the inlet conduit 12 and dissipated in the surrounding atmosphere.
It will be understood that the flow of nitrogen 16 into and out of the expansionchamber 14 is continuous while the maintenance of the flow at atmospheric pressure ensures the unimpaired operability of a Bucholtz relay 22 in the event of electrical failure.
It will be seen then that the present invention offers a safe simple efficient and cost effective means for the substantial elimination of oxidation of transformer insulat-ing oils as commonly used in freely breathing high voltage power transformers byproviding within the transformer tank expansion chamber a continuous flow of inert ~ 21~3580 gas at atmospheric pressure across the surface of the transformer oil thereby dis-placing and eliminating air from inlimdle conlacL with the oil surface while leaving the operability of electrical safety devices unimpaired.
The description contained herein should not be construed as limiting the scope 05 of the invention but rather as an illusl~dlion of the presently prerer,ed embodiment.
Thus the scope of the invention should be dete""ined by the appended claims and their legal equivalent.
Claims (4)
1. A method for the substantial elimination of oxidation of dielectric fluid used in high voltage power transformers comprising the steps of:
generating a continuous flow of inert gas;
introducing said continuous flow of said inert gas to one end of an expansion chamber of said transformer containment vessel; and evacuating said continuous flow of said inert gas at an end of said expansion cham-ber opposite the end wherein the said continuous flow of said inert gas is introduced so that said flow is across the surface of said dielectric fluid and displaces and elimi-nates any air in intimate contact with said surface of said dielectric fluid.
generating a continuous flow of inert gas;
introducing said continuous flow of said inert gas to one end of an expansion chamber of said transformer containment vessel; and evacuating said continuous flow of said inert gas at an end of said expansion cham-ber opposite the end wherein the said continuous flow of said inert gas is introduced so that said flow is across the surface of said dielectric fluid and displaces and elimi-nates any air in intimate contact with said surface of said dielectric fluid.
2. The method of claim 1 wherein said inert gas is nitrogen.
3. The method of claim 1 wherein said continuous flow is maintained at atmospheric pressure.
4. An apparatus for the substantial elimination of oxidation of dielectric fluid used in high voltage power transformer comprising:
a dielectric fluid filled high voltage transformer containment vessel having an expan-sion chamber connected to an upper end of said containment vessel via a constricted channel, said expansion chamber containing a slight head of said dielectric fluid; and means for generating a continuous flow of inert gas at atmospheric pressure, said means located in close proximity to said containment vessel and connected by at least one conduit to said expansion chamber so that said continuous flow of said inert gas is introduced via said conduit into said expansion chamber at one end, flowsacross the surface of said dielectric fluid and is evacuated at the other end of said expansion chamber.
a dielectric fluid filled high voltage transformer containment vessel having an expan-sion chamber connected to an upper end of said containment vessel via a constricted channel, said expansion chamber containing a slight head of said dielectric fluid; and means for generating a continuous flow of inert gas at atmospheric pressure, said means located in close proximity to said containment vessel and connected by at least one conduit to said expansion chamber so that said continuous flow of said inert gas is introduced via said conduit into said expansion chamber at one end, flowsacross the surface of said dielectric fluid and is evacuated at the other end of said expansion chamber.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US20263194A | 1994-02-28 | 1994-02-28 | |
| US08/202,631 | 1994-02-28 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA2143580A1 true CA2143580A1 (en) | 1995-08-29 |
Family
ID=22750681
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA 2143580 Abandoned CA2143580A1 (en) | 1994-02-28 | 1995-02-28 | Method and apparatus for the substantial elimination of oxidation in transformer insulating oils |
Country Status (1)
| Country | Link |
|---|---|
| CA (1) | CA2143580A1 (en) |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US7049922B2 (en) | 2001-12-05 | 2006-05-23 | Insoil Canada Ltd. | Method and apparatus for decreasing gassing and decay of insulating oil in transformers |
| WO2011134050A1 (en) * | 2010-04-26 | 2011-11-03 | Insoil Canada Ltd. | Apparatus and method of dehydration of transformer insulating oil by continuous fluid flow |
-
1995
- 1995-02-28 CA CA 2143580 patent/CA2143580A1/en not_active Abandoned
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US7049922B2 (en) | 2001-12-05 | 2006-05-23 | Insoil Canada Ltd. | Method and apparatus for decreasing gassing and decay of insulating oil in transformers |
| US7205874B2 (en) | 2001-12-05 | 2007-04-17 | Insoil Canada Ltd. | Method and apparatus for decreasing gassing and decay of insulating oil in transformers |
| WO2011134050A1 (en) * | 2010-04-26 | 2011-11-03 | Insoil Canada Ltd. | Apparatus and method of dehydration of transformer insulating oil by continuous fluid flow |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| FZDE | Dead |