WO2014131244A1 - Carton comprimé électriquement isolant et dispositif électrique comprenant ce carton comprimé - Google Patents
Carton comprimé électriquement isolant et dispositif électrique comprenant ce carton comprimé Download PDFInfo
- Publication number
- WO2014131244A1 WO2014131244A1 PCT/CN2013/075260 CN2013075260W WO2014131244A1 WO 2014131244 A1 WO2014131244 A1 WO 2014131244A1 CN 2013075260 W CN2013075260 W CN 2013075260W WO 2014131244 A1 WO2014131244 A1 WO 2014131244A1
- Authority
- WO
- WIPO (PCT)
- Prior art keywords
- pressboard
- electrically insulating
- polysulfonamide
- fiber
- fibrid
- 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.)
- Ceased
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Classifications
-
- D—TEXTILES; PAPER
- D21—PAPER-MAKING; PRODUCTION OF CELLULOSE
- D21J—FIBREBOARD; MANUFACTURE OF ARTICLES FROM CELLULOSIC FIBROUS SUSPENSIONS OR FROM PAPIER-MACHE
- D21J3/00—Manufacture of articles by pressing wet fibre pulp, or papier-mâché, between moulds
Definitions
- the present invention relates to an electrically insulating pressboard comprising polysulfonamide fibrid and polsulfonamide fiber and to an electrical device comprising the same.
- Insulation of oil-filled distribution and power transformers may be made from cellulose and polymer pressboard.
- the cellulose pressboards are mainly used in transformers with relatively lower thermal stability requirements, and polymer pressboards are mainly for transformers with relatively higher thermal stability requirements.
- Nomex from Dupont is typical commercially available polymer pressboard.
- cellulose pressboards are more extensively used than polymer ones. The major reason is that the cost of cellulose pressboard is much lower than those made of polymer.
- the combination of cellulose and polymer pressboard are also used for the balance of thermal stability and cost.
- the cellulose and polymer raw materials are converted by machines to pressboard, which is further converted to different insulation elements used in transformers. These elements include spacers, barriers, press rings and strips.
- Cellulose pressboards are mostly made from cellulose pulp fiber.
- the cellulose pulp fiber is prepared and then dried in sheets, by heating and pressing at the same time.
- Polymer pressboards are mostly made of polymer fiber and polymer fibrid.
- the polymer fiber for paper and pressboard preparation is short fiber which is generally made of normal continuous fiber with regular diameter, the short polymer fiber could be treated by further beating to develop their sheetmaking properties.
- the polymer fibrid a type of fibrous particle used for binding, is with irregular shape and made from polymer solution, the normal process for polymer fibrid preparation is to get the polymer solution in a polar organic solvent first, then get the suspension of polymer fibrid by putting the polymer solution into the high shearing coagulation bath with the mixture of water and polar organic solvent as coagulation bath and finally get the fibrid by washing and filtrating the suspension of polymer fibrid in water several times to remove the polar organic solvent and the water.
- the polymer fibrid could be treated by further beating to develop their sheetmaking properties.
- the polymer pressboard contains both polymer fiber and polymer fibrid.
- the Nomex pressboard from Dupont which is made from poly (metaphenylene isophthamide) fiber and poly (metaphenylene isophthamide) fibrid, has been used as key insulation part for transformer and generator successfully where the high thermal stability is necessary.
- Nomex pressboard While there are still some problems with Nomex pressboard, one problem is the moisture absorption of Nomex pressboard is very high, at about 4% or even higher, the transformer and generator manufacturers need long pretreatment time to remove the moisture inside the pressboard, if there is pressboard with lower moisture content, the manufacturers can substantially shorten the pretreatment time of pressboard, which will result in the lower fabrication cost obviously; another problem is the dielectric strength of Nomex pressboard in transformer oil is not so good, the dielectric strength of Nomex T994 after vacuum immersion treatment in transformer oil for 48 hour is about 30kV/mm. A pressboard with low moisture absorption, high dielectric strength in oil and high thermal stability is required in industry.
- CN 101063280A discloses a synthetic fiber paper, which comprises polyester chopped fiber which is necessary for the disclosed paper, nylon chopped fiber, aramid chopped fiber or polysulfonamide fiber, aramid pulp or polysulfonamide pulp, felt fiber and dispersing auxiliary agent.
- polyester could decrease the paper cost while the thermal stability is also deteriorated
- the thermal class of NMN laminates which comprise both polyester and aramid is F with using temperature of 155°C
- the thermal class of Nomex is H with using temperature of 180°C and even higher. Indeed the introduction of other unstable polymer compared to polysulfonamide also will deteriorate the thermal stability of the final material.
- CN 101892611A discloses a process to prepare a polysulfonamide paper, the dielectric strength of polysulfonamide paper with thickness of 0.15mm is only 13.5kV/mm, which is not so good, as the dielectric strength of Nomex T410 paper with thickness of 0.13mm is about 27kV/mm and that of Nomex T410 paper with thickness of 0.18mm is about 33kV/mm.
- an electrically insulating pressboard which comprises fiber and fibrid, wherein the fibrid is polysulfonamide fibrid.
- the fibrid in the electrically insulating pressboard may have a specific surface area of 3 m 2 /g to 80 m 2 /g, preferably 10 m 2 /g to 40 m 2 /g.
- the fiber in the electrically insulating pressboard is polysulfonamide fiber.
- the fibers may have a length of 1 mm to 20 mm and preferably 2 mm to 7 mm.
- the polysulfonamide fiber is present in the electrically insulating pressboard in an amount of from 10 to 90 wt , preferably 30 wt to 70 wt
- the polysulfonamide fibrid is present in the electrically insulating pressboard in an amount of from 10 wt to 90 wt , preferably 30 wt to 70 wt , based on the total weight of the electrically insulating pressboard.
- the electrically insulating pressboard may further comprise a nano filler and the said nano filler may be selected from nano silica, nano alumina or their mixtures.
- the pressboard made from polysulfonamide fibrid and polysulfonamide fiber showed excellent dielectric strength in oil and low moisture absorption.
- the pressboard with 60 wt polysulfonamide fibrid and 40 wt polysulfonamide fiber displays excellent performance compared with Nomex pressboard, the dielectric strength in oil is more than 50kV/mm and the moisture absorption is lower than 1%.
- Fig 1 is a schematic flow chart of an embodiment of a method according to the present invention.
- an electrically insulating pressboard comprising fiber and fibrid, wherein the fibrid is polysulfonamide fibrid.
- the fibrid used in the electrically insulating pressboard may have a specific surface area of 3 m 2 /g to 80 m 2 /g.
- the more preferred fibrid may have a specific surface area of 10 m7g to 40 m g.
- the fiber is polysulfonamide fiber.
- the fiber used in the electrically insulating pressboard may have a length of 1 mm to 20 mm, preferably 2 mm to 7 mm.
- the electrically insulation pressboard essentially comprises polysulfonamide fiber and polysulfonamide fibrid.
- the polysulfonamide fiber is present in the electrically insulation pressboard in an amount of from 10 to 90 percent by weight, preferably 30 to 70 wt%.
- the polysulfonamide fibrid can be used in an amount of 10 wt% to 90 wt%, based on the total weight of the electrically insulation pressboard.
- the polysulfonamide fibrid is used in an amount of 30 wt% to 70 wt%, based on the total weight of the electrically insulation pressboard.
- the electrically insulating pressboard may further comprise fillers.
- the fillers are nano fillers.
- the amount of the nano fillers is preferably from 0 wt% to 10 wt%, based on the total weight of the electrically insulation pressboard.
- the specific types of filler There is no limitation to the specific types of filler, provided that better dielectric strength and electrical creepage resistance can be obtained.
- Commonly used nano fillers in the field are nano silica, nano alumina and/or their mixture.
- the pressboard comprises 60% polysulfonamide fibrid and 40% polysulfonamide fiber based on the total weight of the pressboard
- the pressboard showed excellent dielectric strength in oil, and lower moisture content.
- the dielectric strength in oil can be improved to more than 50kV/mm, which is much higher than that of Nomex T994 pressboard, which is about 30kV/mm.
- the pressboard had a moisture content of about 0.9 wt , which is much lower than Nomex T994 pressboard, which is more than 4%.
- the lower moisture content can substantially shorten the pretreatment time of pressboard for transformer application, which results in the lower fabrication cost. With the improved dielectric strength in oil, the transformer could have better performance stability.
- the pressboard according to the present invention has a thickness of higher than 0.9 mm. More preferably, the thickness of the pressboard is 1-12 mm, and most preferably 1-8 mm.
- the pressboard is electrically insulating and is suitable for use as insulation material in an electrical device.
- the pressboard may be, for example, used as electrical insulation in an electrical device, such as in a power transformer, whereby the pressboard may be a high voltage insulation material.
- the electrically insulating pressboard may have especially beneficial electrically insulating properties in an oily environment.
- the electrically insulating pressboard may be at least partly soaked in oil.
- the present invention further provides an electrical device comprising the electrically insulating pressboard according to the present invention.
- the electrical device may be any electrical device which comprises electrical insulation, e.g. an electrical transformer or an electrical motor, which may especially benefit from the pressboard, such as with lower moisture absorption, less pretreatment time is needed for the removal of moisture.
- the electrical device according to the present invention is an electrical transformer.
- the electrically insulating pressboard may be in the form of a spacer, barrier, strip or press ring for insulation of an electrical device, such as an electrical transformer.
- the electrically insulating pressboard has electrically insulating properties which may be useful in any electrical device but the electrically insulating pressboard may be especially advantageous in an oily environment, such as in an electrical transformer.
- the electrically insulating pressboard may be used for making electrically insulating spacers in a transformer winding.
- an improved electrical device is obtained by using the electrically insulating pressboard in accordance with the present invention.
- the electrically insulation pressboard displays lower moisture absorption and improved dielectric strength in oil.
- Fig 1 is a schematic flow chart of an embodiment of a method 1 according to the present invention for producing polysulfonamide based electrical insulation pressboard, e.g. for an electrical transformer.
- Fibrids are provided, see 2, and fibers are also provided, see 3.
- the fibrids and fibers are then mixed with each other, see 4.
- a pressboard press, multi-daylight hot press of the like, is then used for pressing the mixture to provide a pressboard see 5.
- the pressing also comprises heating, see 6, and drying the mixture, see 7, as well as pressing the mixture to the pressboard, see 8.
- the pressboard was then cooled, see 9.
- the cooled pressboard may then be cut into desired insulation parts, for example, for use in a transformer or any other electrical device. For instance, a spacer, barrier, strip or press ring for insulation of an electrical transformer, can be produced from the pressboard from this invention.
- An electrically insulation pressboard according to the present invention which is comprising polysulfonamide fibrid and polysulfonamide fiber, was produced and tested for its properties under the IEC (International Electrotechnical Commission) standard 60641-2.
- a pressboard was made according to the process in Figure 1.
- the solid materials used in the making of this pressboard were 60 weight percent of polysulfonamide fibrid (Shanghai Tanlon Fiber Co., Ltd) and 40 weight percent of polysulfonamide fiber (Shanghai Tanlon Fiber Co., Ltd).
- This pressboard had a basic weight of 1160 g/m , a thickness of 1 mm and a density of 1.16 g/cm 3 .
- the weight reduction of the final pressboard is 0.93%, 0.94%, 0.94% and 0.94% after drying for 24h, 48h, 168h and 288h respectively according to IEC 60641-2, item 13, and the weight reduction of Nomex T994 is 3.08%, 3.31%, 3.97% and 4.1% after drying for 24h, 48h, 168h and 288h respectively. It is clear that the moisture content of invented pressaboard is much lower than that of the commercialized Nomex pressboard T994, the transformer manufacturers can substantially shorten the pretreatment time of pressboard, which will result in lower fabrication cost obviously.
- the dielectric strength of the invented pressboard in oil is 53kV/mm, while the dielectric strength of Nomex T994 is about 30kV/mm which is much lower than that of the invented pressboard.
- the 5% decomposition temperature of the invented pressboard determined by thermogravimetry analyzer (TGA) in air with heating rate of lOoC/min is about 432°C and that of the Nomex T994 pressboard is about 421 °C.
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- Engineering & Computer Science (AREA)
- Manufacturing & Machinery (AREA)
- Organic Insulating Materials (AREA)
Abstract
L'invention concerne un carton comprimé électriquement isolant présentant une excellente rigidité diélectrique dans l'huile et une faible absorption de l'humidité. L'invention concerne également un dispositif électrique comprenant ce carton comprimé; le carton comprimé étant réalisé à partir de fibrides de polysulfonamide et de fibre de polysulfonamide.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CNPCT/CN2013/072068 | 2013-03-01 | ||
| CN2013072068 | 2013-03-01 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| WO2014131244A1 true WO2014131244A1 (fr) | 2014-09-04 |
Family
ID=51427501
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| PCT/CN2013/075260 Ceased WO2014131244A1 (fr) | 2013-03-01 | 2013-05-07 | Carton comprimé électriquement isolant et dispositif électrique comprenant ce carton comprimé |
Country Status (1)
| Country | Link |
|---|---|
| WO (1) | WO2014131244A1 (fr) |
Citations (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US20040180185A1 (en) * | 2002-05-02 | 2004-09-16 | Tatsushi Fujimori | Heat-resistant synthetic fiber sheet |
-
2013
- 2013-05-07 WO PCT/CN2013/075260 patent/WO2014131244A1/fr not_active Ceased
Patent Citations (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US20040180185A1 (en) * | 2002-05-02 | 2004-09-16 | Tatsushi Fujimori | Heat-resistant synthetic fiber sheet |
Non-Patent Citations (1)
| Title |
|---|
| RUI, JINGKANG ET AL., PRACTICAL ELECTRICAL MATERIALS GUIDE, February 2003 (2003-02-01), pages 17 - 20 * |
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