JP5593273B2 - Insulating material and static induction device using the same - Google Patents

Description

  The present invention relates to an insulating paper, an insulator, and a static induction electric machine using the same, which are used in a mineral oil-containing static induction electric machine using mineral oil as an insulating / cooling medium.

  In general, a static induction appliance such as an oil-filled transformer is composed of an iron core, a coil mounted on the iron core and wound with insulating paper, and a coil insulating paper and an insulating cooling medium such as mineral oil in a tank. A winding provided with an insulator for forming a cooling passage for the insulating medium is immersed.

  When the insulating cooling medium flows by natural convection or pressurization inside such a static induction electric device, charge separation occurs at the interface between the insulating cooling medium and the insulating paper or solid insulator, and the insulating paper or solid insulator Then, electrostatic charging occurs. When the charge density accumulated in the insulating paper or the solid insulator is increased, the DC potential of the portion is increased and electrostatic discharge is generated. When the electrostatic discharge progresses, dielectric breakdown may occur. This phenomenon is generally known as fluid charging. For this reason, there is a demand for the development of a method for suppressing the flow charge of an oil-filled transformer that grasps the charging characteristics of an insulator and suppresses an increase in the degree of charge.

  Patent Document 1 describes the use of a porous low-charge member on the insulating member surface of the cooling passage surface through which insulating oil passes. Patent Document 3 describes that the surface resistance of insulating paper is reduced. Patent Document 2 describes that a part of cellulose constituting insulating paper is etherified, or an ether compound is mixed, internally added, or applied.

JP-A-11-16741 Japanese Patent Laid-Open No. 1-185905 JP-A-53-15518

Electrical Engineering B, Vol.128, No.3, 2008

  In the case of Patent Document 1 and Patent Document 2, since an organic film is attached to the surface of the insulating paper, a film bonding process different from the paper making process is required, and there are problems that equipment and processes increase and costs increase. It was. In the case of Patent Document 4, since a part of cellulose is etherified or an ether compound is mixed, added, or applied, there is a problem that hydrogen bonds in the insulating paper are reduced and strength is lowered.

  An object of the present invention is to provide an insulating paper that can suppress electrostatic charge in a coolant circulation path and an increase in flow charge due to aging in an oil-filled transformer, and insulation made using the insulating paper. It is to provide a body and a transformer using the body.

  An object of the present invention is to provide a coil comprising an iron core and an electric wire wound with insulating paper attached to the iron core in an insulating cooling medium having mineral oil in the transformer body, an insulator for coil insulation, and the insulation. An insulating material including an insulating paper and an insulating material used for a static induction electric device formed by immersing an insulating material constituting a cooling passage of a cooling medium.

The main configuration of the present invention is shown below.
(1)
A stationary induction that is a pulp-based insulating material used by being immersed in mineral oil used as an insulating cooling medium, and at least the amount of Ca ions on the surface of the insulating material is reduced to 0.06 wt% or less. Insulation material for electrical appliances.
(2)
In the above (1), the amount of Ca ions on the surface of the insulating material is reduced to 0.06 wt% or less, and the total amount of Na ions, K ions, Ca ions, and Mg ions is reduced to 0.1 wt% or less. Insulation material for static induction machines. The total amount of Na ions, K ions, Ca ions, and Mg ions is also the amount of the surface of the insulating material. The surface of the insulating material is a region from the surface of the insulating material to a depth of 100 μm.
(3)
In the above (1), the amount of Ca ions from the surface of the insulating material to a depth of 100 μm is reduced to 0.06 wt% or less, and the total amount of Na ions, K ions, Ca ions, and Mg ions is 0.1 wt%. Insulating material for static induction equipment that has been reduced to less than%.
(4)
In any one of the above (1) to (3), the insulating material is an insulating paper wound around an electric wire constituting a coil attached to an iron core of a static induction electric appliance, and an insulating cooling medium of the static induction electric appliance. An insulating material for a static induction electric appliance which is either or both of the insulators constituting the cooling passage.
(5)
Insulating paper for static induction appliances in which the amount of Ca ions on at least the surface of insulating paper containing pulp as a main material is reduced to 0.06 wt% or less.
(6)
In the above (5), the amount of Ca ions on at least the surface of the insulating paper is 0.06 wt% or less, and the total amount of Na ions, K ions, Ca ions, and Mg ions is 0.1 wt% or less. Insulating paper for electrical appliances.
(7)
In the above (6), the amount of Ca ions from the insulating paper surface to a depth of 100 μm is reduced to 0.06 wt% or less, and the total amount of Na ions, K ions, Ca ions, and Mg ions is 0.1 wt%. Insulation paper for static induction machines reduced to the following.
(8)
An insulator for static induction electric appliances in which the amount of Ca ions contained in at least the surface of an insulating pressboard material mainly composed of pulp is reduced to 0.06 wt% or less.
(9)
In the above (8), the amount of Ca ions on at least the surface of the press board material is 0.06 wt% or less, and the total amount of Na ions, K ions, Ca ions, and Mg ions is 0.1 wt% or less. Insulator for induction machine.
(10)
In the above (8), the amount of Ca ions from the surface of the insulating press board material to a depth of 100 μm is reduced to 0.06 wt% or less, and the total amount of Na ions, K ions, Ca ions, and Mg ions is reduced to 0. .Insulator for static induction appliances reduced to 1 wt% or less.
(11)
In an insulating cooling medium having mineral oil in the transformer body, an iron core, a coil made of an electric wire wound with insulating paper attached to the iron core, a coil insulating insulator, and a cooling passage for the insulating cooling medium are provided. In a static induction electric appliance formed by immersing a constituent insulator, the insulating paper and / or the insulator is mainly made of pulp, and at least the surface of the insulating paper and / or the insulator has an amount of Ca ions of 0.06 wt. The static induction device is reduced to less than%.
(12)
In the above (11), the insulating paper and / or the insulator is such that the amount of Ca ions on at least the surface of the insulating paper is 0.06 wt% or less, and the total amount of Na ions, K ions, Ca ions, and Mg ions. Is an insulating paper that is 0.1 wt% or less.
(13)
In the above (11), the amount of Ca ions from the surface of the insulating paper and / or insulator to a depth of 100 μm is reduced to 0.06 wt% or less, and Na ions, K ions, Ca ions, Mg A static induction device in which the total amount of ions is reduced to 0.1 wt% or less.

The insulating material in the present invention is made of pulp and is subjected to treatment such as impregnation of varnish as necessary. However, it is usually composed only of a pulp material in order to maintain insulating properties. Insulators are used to form a flow path for the cooling medium of static induction appliances. Many sheets of insulating paper manufactured as wet paper are laminated, dried and pressed to be integrated (laminated product), or kraft pulp. Etc. are made thick and pressed and dried. This may be treated with a treatment material such as varnish as necessary. This insulating material is well known as a press board.
The insulating paper according to the present invention has pulp as a main material and at least the amount of Ca ions contained on the surface thereof is reduced to 0.06 wt% or less. The insulator according to the present invention is obtained by laminating and integrating the above insulating papers. Therefore, the distinction between insulating paper and insulator is, in a normal sense, an article having a thickness that can be wound around a conductor to form a coil is relatively thicker than insulating paper and insulating paper, and has a certain shape maintaining property. What has it is called an insulator.

  Further, the amount of Ca ions contained in the insulating paper or insulator is reduced to 0.06 wt% or less, and the total amount of Na ions, K ions, Ca ions, and Mg ions is reduced to 0.1 wt% or less. It is characterized by.

  Furthermore, the amount of Ca ions from the surface of the insulating paper or insulator to a depth of 100 μm is reduced to 0.06 wt% or less.

  Furthermore, the amount of Ca ions from the surface of the insulating paper or insulator to a depth of 100 μm is reduced to 0.06 wt% or less, and the total amount of Na ions, K ions, Ca ions, and Mg ions is 0.1 wt% or less. It is characterized by having been reduced.

  A static induction electric appliance according to the present invention includes an iron core, a coil formed by winding an insulating paper attached to the iron core in an insulating cooling medium having mineral oil in the transformer body, an insulator for coil insulation, In a static induction electric appliance formed by immersing an insulator constituting a cooling passage of the insulating cooling medium, the amount of Ca ions on at least the surface of the insulating paper is 0.06 wt% or less, preferably Na ions, K ions, The total amount of Ca ions and Mg ions is 0.1 wt% or less, and the insulator is obtained by laminating and integrating the insulating paper.

  The Ca ion on the surface of the insulating paper or insulator of the static induction device can be 0.06 wt% or less, and the total amount of Na ions, K ions, Ca ions, and Mg ions can be 0.1 wt% or less. Further, the amount of Ca ions from the surface of the insulating paper or insulator to a depth of 100 μm is reduced to 0.06 wt% or less, and the total amount of Na ions, K ions, Ca ions, and Mg ions is 0.1 wt% or less. Can be reduced to a very low level.

  According to the present invention, by reducing the amount of metal ions on the surface of the insulating paper or the insulator, there is no need for a step of film bonding different from the paper making step, and without reducing the strength of the insulating paper. In the oil-filled transformer, it is possible to provide insulating paper that can suppress electrostatic charge in the coolant circulation path and suppress increase in flow charge due to aging, and a transformer using the insulating paper.

BRIEF DESCRIPTION OF THE DRAWINGS The longitudinal cross-sectional view which shows the oil-filled transformer of Example 1 of this invention. The graph which shows the XPS analysis result of the aged press board surface. The graph which shows the XPS analysis result about S amount inside aged press board. The graph which shows the XPS analysis result about Ca content inside an aged press board. The cross-sectional schematic diagram of a press board material.

  Embodiments of the present invention will be described below with reference to the drawings. An oil-filled transformer will be described as an example of a stationary induction device containing mineral oil using mineral oil as an insulating cooling medium to which the flow charge diagnostic method of the present invention is applied. FIG. 1 is a longitudinal sectional view showing an oil-filled transformer.

  An insulating support base 3a is placed on the lower support fitting 2 attached to the lower part of the iron core 1, and inter-coil spacers 4a and disk coils 5a are alternately stacked on the insulating support base 3a to form a low voltage winding 6. ing. An electrostatic shield 7 a is placed on the top of the low-voltage winding 6. A linear spacer 8 is applied to the outside of the low-voltage winding 6, and an insulating paper 9 is wound around the outside to form an insulating cylinder 9. Further, a similar linear spacer 8 and insulating cylinder 9 are arranged outside the main cylinder 10. Is forming.

  A disk coil 5b is formed by winding an electric wire on the outer side of the linear spacer 8 located on the outermost side of the main insulation 10 to form a disk coil 5b, and the disk coil 5b and the inter-coil spacer 4b are alternately stacked to form a high voltage winding 11. It is composed. An electrostatic shield 7 b is provided on the top of the high voltage winding 11.

  The insulating support base 3b is placed on the upper portions of the low-voltage and high-voltage windings 6 and 11 formed in this way, and the upper support fitting 12 with the push bolts 13 mounted thereon is further mounted on the iron core 1. Then, a load is applied to the insulating support 3b with the push bolt 13, and the low-voltage and high-voltage windings 6 and 11 are tightened to constitute the winding body.

  The high-voltage lead wire 14 is pulled out from the upper end of the high-voltage winding 11 and connected to the high-voltage bushing 15. At this time, a support arm 16 having a hole into which the high-voltage lead wire 14 is inserted is taken out from the upper support fitting 12. The high-voltage lead wire 14 is placed in the hole and the middle of the lead wire 14 is supported. In addition, a lead wire barrier 18 is disposed by winding an insulating paper through a spacer 17 in a portion where the insulation distance from the periphery of the high voltage lead wire is small. All of these are housed in a transformer body 20 filled with mineral oil 21 to form a disk winding transformer winding 22.

  As materials for the inter-coil spacers 4a and 4b and the linear spacer 8 used as insulators for insulating and insulating oil cooling passage construction, board materials such as press board made of kraft pulp have been widely used.

  During operation of the oil-filled transformer, mineral oil, which is an insulating cooling medium, flows by convection in the oil-filled transformer, so that solid insulation composed of mineral oil and board materials such as the inter-coil spacers 4a and 4b and the linear spacer 8 is obtained. Charge separation occurs at the interface with the body, and electrostatic charge occurs in the solid insulator.

  Non-Patent Document 1 clearly shows that the charging potential of a pressboard taken from an aged transformer increases, and among the sulfur compounds adsorbed on the surface of the aged pressboard, the amount of sulfide and the increase in the charging potential. While no correlation is observed, it is described that there is a correlation between the amount of sulfoxide and the increase in charged potential.

  On the other hand, as a result of intensive studies on the surface condition of insulating paper such as pressboard, Ca is present in a high concentration on the surface of the aged pressboard after washing with hexane and removing oil components, etc., compared to a new pressboard It was also found for the first time that the Ca concentration had a high correlation with the surface S (sulfur) concentration.

  Fig. 2 shows the result of analyzing the surface with XPS (X-ray Photoelectron Spectroscopy) after washing the new press board and the press board taken from an aged transformer with hexane to remove oil components. It is shown in 2. Moreover, the XPS analysis result inside an aged press board is shown to FIG. 3A and FIG. 3B.

  FIG. 2 shows that the Ca content on the surface of the aged press board has a good correlation with the S content. Since it wash | cleans with hexane in order to remove an oil component, it is thought that the S component which remains on the surface is interacting strongly with Ca. That is, low-polarity components such as sulfides are considered to elute together with oil components by washing with hexane, which is a non-polar solvent, and sulfoxides that are considered to have a strong interaction with ionic components such as Ca. It is thought that it remains on the surface of the press board.

  On the other hand, from FIG. 3B, it was found that the internal Ca concentration was low compared to the surface of the aged press board, and that the inside of the depth of 100 μm or more from the surface was almost the same as a new press board. Further, as shown in FIG. 3A, the internal S concentration is lower than that of the surface of the aged press board, and the concentration is about 1/6 of the surface within the depth of 100 μm from the surface, and the inner depth of 500 μm from the surface. So, like a new press board, it was found that XPS could not detect it.

  The detailed mechanism by which Ca on the surface of the pressboard increases is unknown, but one possibility is that a few metal ions dissolved in the insulating oil were adsorbed on the pressboard surface. In addition, when a highly polar compound such as sulfoxide generated by aging is adsorbed on the surface of the press board, Ca ions are attracted to the sulfoxide and the like, causing Ca to move and diffuse from the inside of the press board to the surface. The concentration may be increased.

  The accumulation of ionic Ca on the surface is thought to increase the charging potential on the surface of the press board over time. Therefore, by reducing the amount of Ca ions on the surface of the insulating paper or the insulator, in the oil-filled transformer, it is possible to suppress electrostatic charge in the coolant circulation path and to suppress increase in flow charge due to aging.

  From the results of FIGS. 3A and 3B, it can be seen that the insulating paper or the pulp material itself of the insulator does not contain so much Ca ions, Na ions, and the like. However, if Ca ions or Na ions adhere to the surfaces of the insulating paper or press board in the manufacturing process, the metal ion concentration on the surface of the insulating material is considered to be higher than the inside. Conventionally, it has been considered that dielectric breakdown of insulating materials is caused by cutting of cellulose molecules due to aging of insulating materials or accumulation of metal ions, etc., so that the initial surface condition of insulating materials, especially metal ions, has not been considered. Conceivable.

  Insulating paper used for transformers is manufactured from kraft pulp, and kraft pulp contains hydroxyl groups and some carboxyl groups. For this reason, it is considered that metal ions such as Ca are captured by these polar groups in the process of producing insulating paper. As metal ions, it is efficient to reduce the amount of Ca ions contained most in the insulating paper, but the insulating paper contains metal ions such as Na, K and Mg in addition to Ca. ing. Therefore, the amount of these metal ions may be reduced. Similarly, in the oil-filled transformer, it is possible to suppress electrostatic charge in the coolant circulation path and to suppress increase in flow charge due to aging. In particular, Na ions are known to lower the insulating properties of insulating paper, and are usually reduced to about 0.05 wt% or less, but there are insulating papers with a lot of Na ions depending on the difference in raw kraft pulp used, In this case, reducing Na ions has a great effect of suppressing electrostatic charging.

  As a method for reducing the amount of metal ions in the insulating paper, kraft pulp or insulating paper can be washed with water. The lower the conductivity of the water used, that is, the smaller the amount of ionic impurities, the greater the effect of reducing the amount of metal ions. The conductivity of water is preferably 10 μS / cm or less. In addition, the greater the number of washings, the greater the effect of reducing metal ions.

  A more effective method for reducing the amount of metal ions is to wash with an acid such as acetic acid. When washing with an acid such as acetic acid, care must be taken not to reduce the strength of the paper.

  In addition, since the surface condition greatly affects the increase in the charging degree of insulating paper, even if the insulating paper is washed with water or acid and the metal ions on the surface are removed, the electrostatic charge can be suppressed, There is an effect of suppressing an increase in flow charge due to aging.

First, insulating papers or insulators according to examples and comparative examples of the present invention will be described.
(1) Reduction of the amount of metal ions in kraft pulp (Examples 1-2), (Comparative Examples 1-2)
By washing the kraft pulp with acid, the amount of Ca ions, and Na ions, K ions, and Mg ions were reduced. As kraft pulp, two types of unbleached kraft pulp A and kraft pulp B used in the manufacture of kraft insulation paper specified in JISC2300-1 and made of only coniferous pulp by the kraft method are 1 / 10N acetic acid. After washing with a solution, washing was performed with water having an electrical conductivity of 5 μS / cm to obtain a Kraft pulp A washed product and a Kraft pulp B washed product in which the amount of Ca ions and the amount of Na ions, K ions, and Mg ions were reduced.

As comparative examples, two types of untreated kraft pulp A and untreated kraft pulp B were used.
(2) Production of insulating paper and insulator (board material) (Examples 3 to 6), (Comparative Examples 3 to 6)
Insulating paper and an insulator (board material) were produced from the four types of kraft pulps of Examples 1-2 and Comparative Examples 1-2 by the following procedure. Wet paper is formed by wet papermaking from an aqueous slurry of kraft pulp, this wet paper is laminated, dried, re-dried with a dryer, and heat calendered to obtain four types of insulating paper with a thickness of about 100 μm. It was. Further, wet paper is formed from the aqueous slurry of the kraft pulp by wet papermaking, and 19 sheets of the wet paper are stacked and integrated by heating and pressing and drying with a hot press at a temperature of 140 ° C. and a pressure of 4 MPa. Four types of board materials of 6 to 1.7 mm were obtained.

(Examples 7 to 8)
Wet paper was formed by wet papermaking from the aqueous slurry of two types of kraft pulp before washing in Comparative Examples 1 and 2, and 15 sheets of this wet paper were stacked on both sides before washing in Comparative Examples 1 and 2. After two wet paper sheets formed by wet papermaking from an aqueous slurry of kraft pulp with reduced metal ion amounts of Examples 1 and 2 corresponding to each of the two types of kraft pulp, were stacked at a temperature of 140 ° C. and a pressure of 4 MPa. Two types of board materials (laminated products) having a thickness of about 1.6 to 1.7 mm, in which the amount of metal ions on the surface was reduced, were integrated by heating and drying by hot pressing.

(Examples 9 to 12)
Two types of insulating paper of Comparative Examples 3 to 4 and two types of board materials of Comparative Examples 5 to 6 prepared with two types of untreated kraft pulp A and untreated kraft pulp B, After soaking in a 10N acetic acid solution, it is soaked in water with a conductivity of 5 μS / cm and washed to reduce the amount of Ca ions on the surface and the amount of Na ions, K ions, and Mg ions. Insulating paper and two kinds of board materials were obtained. The cross-sectional schematic diagram of Examples 7-12 is shown in FIG. In FIG. 4, the press board is formed by laminating a number of wet paper webs 24 and integrating them under pressure, and the press board of the present invention has a layer with reduced Ca ions and the like on its surface.
(3) Measurement of amount of metal ions in kraft pulp, insulating paper and insulator Ca and Mg were analyzed by high frequency inductively coupled plasma emission spectroscopy (ICP-AES) according to the method described in JISK0116. Na and K were analyzed by atomic absorption spectrophotometry (AAS) according to the method described in JISK0121.

  Table 1 shows the analysis results of Examples 1-2 and Comparative Examples 1-2.

  It can be seen that the pulp A and pulp B of Comparative Examples 1 and 2 contain the largest amount of Ca and contain Na, K, Mg, and the like. Compared to Pulp A, Pulp B has slightly less Ca and more Na. The kraft pulps of Examples 1 and 2 obtained by washing with an acetic acid solution of pulp A and pulp B 1 / 10N and then washing with water having a conductivity of 5 μS / cm all have reduced amounts of Ca, Na, and Mg. It can be seen that Ca is 0.06 wt% or less, and the total amount of Na ions, K ions, Ca ions, and Mg ions is 0.1 wt% or less.

  Moreover, Table 2 shows the analysis results of Examples 3 to 6 and Comparative Examples 3 to 6.

Comparative Examples 3 to 6, which are insulating papers and insulators (board materials) prepared from the kraft pulps of Comparative Examples 1 and 2, contain Na, K, Mg, and the like. Slightly less and more Na. On the other hand, in the insulating paper and the insulator (board material) Examples 3 to 6 produced from the kraft pulp of Examples 1 and 2, the amounts of Ca, Na and Mg are all reduced, and Ca is 0.06 wt%. Hereinafter, it turns out that the total amount of Na ion, K ion, Ca ion, and Mg ion is 0.1 wt% or less.
(4) Measurement of the amount of metal ions and sulfur on the insulating paper and the insulator surface It was measured using Shimadzu / KRATOS X-ray photoelectron spectrometer AXIS-HS. The press board in the state of mineral oil impregnation was measured after being immersed in hexane to wash and remove the mineral oil.

  Table 3 shows the XPS measurement results of the manufactured insulating paper and insulator.

  Analysis results of Examples 3 to 6 and Comparative Examples 3 to 6, and measurement results of the board material (laminated product) of Examples 7 to 8, the insulating paper of Examples 9 to 12, or the board material (surface cleaning product) Is shown together.

  The amounts of Ca and Na on the surfaces of the insulating paper and the insulator (board material) in Examples 3 to 12 could not be detected by XPS, or were about 0.1 at% of the detection limit. The amounts of Ca and Na within 100 μm from the surfaces of the insulating paper and the insulator (board material) of Examples 7 to 12 could not be detected by XPS, or about 0.1 at% of the detection limit. Further, K ions and Mg ions could not be detected by XPS.

Further, Table 3 shows XPS measurement results after the insulating papers and insulators (board materials) of Comparative Examples 3 to 6 and Examples 3 to 12 were heated and deteriorated in mineral oil at 140 ° C. for 60 days. . It can be seen that the amount of Ca in Comparative Examples 3 to 6 increased compared to the initial value, whereas the amount of Ca in Examples 3 to 12 hardly changed from the initial value. For Comparative Examples 4 and 6, it was found that the amount of Na also increased.
(5) Measurement of mechanical strength The tensile strength of the produced insulating paper was cut into 15 mm x 250 mm, measured with an AUTOGURAP DSS5000 manufactured by SHIMAZU at a span interval of 180 mm and a tensile speed of 200 mm / min.

The measurement results of Examples 3 to 4, Comparative Examples 3 to 4, and Examples 9 to 10 are shown together in Table 3. The tensile strength of Comparative Example 3 and Comparative Example 4 was set to 100. It was found that all of Examples 3 to 4 and Examples 9 to 10 were almost the same as the tensile strengths of Comparative Example 3 and Comparative Example 4.
(6) Measurement of charging degree The charging degree of the manufactured insulating paper and the insulator was measured by a mixed flow method.

  Table 4 shows the measurement results of the degree of electrification at the initial stage of the insulating paper and the insulator (board material) of Comparative Examples 3 to 6 and Examples 3 to 12 and after heat deterioration.

  For the insulating paper, the initial charging degree of Comparative Example 3 was set to 100. Further, the initial charge of the insulator (board material) in Comparative Example 5 was set to 100.

  The charge of the insulating paper and the insulator (board material) in Examples 3 to 12 is lower than the charge of the insulating paper and the insulator (board material) using the same kraft pulp in Comparative Examples 3 to 6, respectively. . In addition, although the degree of charging after thermal deterioration increases, it is confirmed that the rate of increase in the degree of charging of the insulating paper and the insulator (board material) of Examples 3 to 12 is lower than that of Comparative Examples 3 to 6. did.

  As described above, by using the insulating paper and the insulator (board material) of Examples 3 to 12, in the oil-filled transformer, the electrostatic charge of the coolant circulation path is suppressed, and further, the increase of the flow charge due to aging is suppressed. can do. As for the insulating paper and the insulator (board material), it is possible to produce one having a thickness changed as necessary by the same method. In addition, an insulator having a complicated shape can be manufactured by using a mold or the like. When producing with a mold or the like, the raw material pulp may be washed to reduce the amount of Ca ions and the amount of Na ions, K ions, and Mg ions, and the produced insulator surface may be washed to produce Ca ions. The amount of Na ions, K ions, and Mg ions can also be reduced.

DESCRIPTION OF SYMBOLS 1 ... Iron core, 6 ... Low voltage winding, 8 ... Linear spacer, 9 ... Insulating cylinder, 10 ... Main insulation, 11 ... High voltage winding, 17 ... Spacer, 20 ... Transformer main body, 21 ... Mineral oil, 22 ... Transformer Winding, 23 ... Part with reduced amount of metal ions

Claims (13)

It is used by dipping in mineral oil used as an insulating cooling medium, and is an insulating material mainly composed of pulp,
The insulating material is composed of insulating paper whose main material is pulp,
An insulating material for a static induction appliance, wherein at least the amount of Ca ions on the surface of the insulating material is reduced to 0.06 wt% or less.   In Claim 1, the amount of Ca ions on the surface of the insulating material is reduced to 0.06 wt% or less, and the total amount of Na ions, K ions, Ca ions, and Mg ions is reduced to 0.1 wt% or less. Insulating material for static induction appliances.   2. The amount of Ca ions from the surface of the insulating material to a depth of 100 μm is reduced to 0.06 wt% or less, and the total amount of Na ions, K ions, Ca ions, and Mg ions is 0.1 wt%. An insulating material for a static induction machine, characterized by being reduced to the following. In claim 1, wherein the insulating material constitutes a wound insulating paper loaded coil to the core of the stationary induction apparatus, the cooling passages of the stationary induction apparatus of the insulating coolant insulation An insulating material for a static induction device, characterized by being either or both of a body. Insulating paper for stationary induction equipment used by being immersed in mineral oil used as an insulating cooling medium,
Insulating paper for static induction appliances characterized in that the amount of Ca ions on at least the surface of insulating paper mainly composed of pulp is reduced to 0.06 wt% or less.   6. The amount of Ca ions on at least the surface of the insulating paper is 0.06 wt% or less, and the total amount of Na ions, K ions, Ca ions, and Mg ions is 0.1 wt% or less. Insulating paper for static induction machine.   6. The amount of Ca ions from the insulating paper surface to a depth of 100 μm is reduced to 0.06 wt% or less, and the total amount of Na ions, K ions, Ca ions, and Mg ions is 0.1 wt% or less. Insulating paper for static induction appliances, characterized in that An insulator for a static induction appliance used by being immersed in mineral oil used as an insulating cooling medium,
An insulator for static induction appliances, characterized in that the amount of Ca ions contained in at least the surface of an insulating pressboard material mainly composed of pulp is reduced to 0.06 wt% or less.   The amount of Ca ions on at least the surface of the press board is 0.06 wt% or less, and the total amount of Na ions, K ions, Ca ions, and Mg ions is 0.1 wt% or less. Insulator for static induction equipment. According to claim 8, wherein the amount of Ca ions to a depth of 100μm from the surface of the insulating pressboard reduced below 0.06 wt%, One or, Na ions, K ions, Ca ions, the total amount of Mg ions 0. An insulator for static induction appliances, characterized by being reduced to 1 wt% or less.   In an insulating cooling medium having mineral oil in the transformer body, an iron core, a coil made of an electric wire wound with insulating paper attached to the iron core, a coil insulating insulator, and a cooling passage for the insulating cooling medium are provided. In a static induction electric appliance formed by immersing a constituent insulator, the insulating paper and / or the insulator is mainly made of pulp, and at least the surface of the insulating paper and / or the insulator has an amount of Ca ions of 0.06 wt. A static induction device characterized by being reduced to less than%. 12. The insulating paper and / or insulator according to claim 11, wherein the amount of Ca ions on at least the surface of the insulating paper is 0.06 wt% or less, and the total amount of Na ions, K ions, Ca ions, and Mg ions is A static induction machine characterized by being an insulating paper of 0.1 wt% or less. 12. The total amount of Na ions, K ions, Ca ions, and Mg ions in claim 11, wherein the amount of Ca ions from the surface of the insulating paper and / or insulator to a depth of 100 μm is reduced to 0.06 wt% or less. Is a static induction electric appliance characterized by being reduced to 0.1 wt% or less.

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