JP4558764B2 - Static induction machine with tap changer when loaded - Google Patents

Description

  The present invention relates to a static inductor containing a flame retardant liquid, which includes a load tap changer and uses a flame retardant liquid insulator as an insulation / cooling medium.

  Conventionally, an insulating oil such as mineral oil has been used as an insulating / cooling medium for a transformer, which is a stationary inductor using an insulating / cooling medium.

  The fire resistance of the transformer can be improved by using a flame retardant silicone liquid as an insulation / cooling medium for the transformer in place of the mineral oil. Along with this, fire resistance is also required for the on-load tap changer for voltage adjustment provided in the transformer.

  The on-load tap changer is mainly composed of a switching switch part and a tap selector part. Patent Document 1 discloses an on-load tap changer using an ester oil or liquid silicone having a flash point of more than 250 ° C. for the switching switch unit and a natural ester oil having a flash point of more than 250 ° C. for the tap selector unit. Is described. Further, it is described that synthetic ester oil is used instead of natural ester oil. Further, a liquid silicone having a flash point exceeding 250 ° C. is used for the switching switch portion, a liquid silicone having a flash point exceeding 250 ° C. is used for the tap selector portion, and a load using a low sliding resistance type tap switch is used. An hour tap changer is described.

  As a tap changer, a vacuum switch type on-load tap changer that prevents arcing in the medium has been proposed and put into practical use.

JP 2006-114615 A

  In the method described in Patent Document 1, when liquid silicone is used for the switching switch part, the liquid silicone is polymerized when an arc is generated, thereby generating an insulator, which may cause poor contact of the switching switch part. In addition, when liquid silicone is used for the tap selector, the metal of the tap selector is worn even when a low sliding resistance type tap changer is used for liquid silicone with poor lubrication characteristics of the sliding part between the metals. there's a possibility that. In addition, when natural or synthetic ester oil is used for the switching switch or tap selector, it is difficult to make a flame-retardant device, and the volume resistivity is low, and the insulation characteristics are reduced due to degradation due to hydrolysis. there's a possibility that.

  An object of the present invention is to provide a stationary inductor having an on-load tap changer that has excellent fire resistance and exhibits stable operability for a long period of time.

The present invention includes a tank, an electromagnetic induction device housed in the tank with a liquid insulator having a flash point exceeding 250 ° C., and a load tap changer that adjusts the voltage of the electromagnetic induction device. The hour tap changer comprises a switching switch part and a tap selection part, and at least as an insulating medium of the tap selection part, a polyol ester having a flash point exceeding 250 ° C. in a ratio of 5 to 30% by weight of the insulating medium weight. The present invention provides a static induction machine with a tap changer at load, which is filled with an added silicone liquid. The polyol ester is a neopentyl glycol polyol ester represented by the formula (1), a trimethylolpropane polyol ester represented by the formula (2), or a pentaerythritol polyol ester represented by the formula (3). And one or more polyol esters selected from the group consisting of dipentaerythritol-based polyol esters represented by formula (4).
_{(R1-CH 2) 2 -C-} (CH 2 -O (CO) -R2) 2 ···· formula (1)
_{R1-CH 2 -C- (CH 2} -O (CO) -R2) 3 ···· formula (2)
C— (CH ₂ —O (CO) —R ₂ ) ₄ ... Formula (3)
_{(R2- (CO) O-CH} 2) 4 -CH 2 -O-CH 2 -C- (CH 2 -O (CO) -R2) 4 ···· formula (4)
(Wherein R1 is hydrogen or an alkyl group having 1 to 3 carbon atoms, and R2 is one or more of an alkyl group having 5 to 12 carbon atoms)

  According to the present invention, an on-load tap excellent in fire resistance that satisfies the insulation characteristics and arc resistance required for the switching switch part and also satisfies the insulation characteristics and sliding characteristics required for the tap selector part. It is possible to provide a static inductor containing a silicone liquid with a switching device.

  Next, an electrical apparatus containing a silicone liquid according to an embodiment of the present invention will be described with reference to the drawings. In addition, it is as follows if embodiment of this invention is illustrated.

  (1) A tank, an electromagnetic induction device housed in the tank with a liquid insulator having a flash point exceeding 250 ° C., and a load tap changer that adjusts the voltage of the electromagnetic induction device. The tap changer includes a switching switch part having a vacuum switch and a tap selection part, and the flash point exceeds 250 ° C. at a rate of 5 to 30% by weight of the insulation medium weight as the insulation medium of at least the tap selection part. It is a static induction machine with a tap changer at the time of loading filled with a silicone liquid to which a polyol ester is added.

(2) The synthetic ester oil is preferably one or more polyol esters selected from the group consisting of the following formulas (1) to (4), that is, hindered type polyol esters.
_{(R1-CH 2) 2 -C-} (CH 2 -O (CO) -R2) 2 ···· formula (1)
_{R1-CH 2 -C- (CH 2} -O (CO) -R2) 3 ···· formula (2)
C— (CH ₂ —O (CO) —R ₂ ) ₄ ... Formula (3)
_{(R2- (CO) O-CH} 2) 4 -CH 2 -O-CH 2 -C- (CH 2 -O (CO) -R2) 4 ···· formula (4)
(Wherein R1 is hydrogen or an alkyl group having 1 to 3 carbon atoms, and R2 is one or more of an alkyl group having 5 to 12 carbon atoms)
(3) The silicone liquid is a dimethyl silicone in which the side chain of the polysiloxane represented by the following formula (5) is a methyl group, and the methyl phenyl silicone in which a part of the side chain of the polysiloxane represented by the formula (6) is a phenyl group. One or more selected from the group consisting of

(4) It is preferable that the kinematic viscosity coefficient of the silicone liquid at 25 ° C. is 50 mm ² / s or less.

(5) On-load tap switching having a tank, a stationary inductor housed in the tank with an insulating medium containing silicone liquid, a switching switch unit for adjusting the voltage of the stationary inductor, and a tap selector unit The load tap changer is a vacuum switch, and the insulation medium of the tap selector part of the load tap changer is represented by the formulas (1) to (4) whose flash point exceeds 250 ° C. A static induction electric appliance with a tap changer on load, which is a silicone liquid to which one or more synthetic polyol esters selected from the group are added.
_{(R1-CH 2) 2 -C-} (CH 2 -O (CO) -R2) 2 ···· formula (1)
_{R1-CH 2 -C- (CH 2} -O (CO) -R2) 3 ···· formula (2)
C— (CH ₂ —O (CO) —R ₂ ) ₄ ... Formula (3)
_{(R2- (CO) O-CH} 2) 4 -CH 2 -O-CH 2 -C- (CH 2 -O (CO) -R2) 4 ···· formula (4)
(In the formula, R1 is hydrogen or any one or more of alkyl groups having 1 to 3 carbon atoms, and R2 is any one or more of alkyl groups having 5 to 12 carbon atoms)
(6) The silicone liquid is preferably one or more selected from the group consisting of silicones represented by the following formulas (5) and (6).

(7) The content of the synthetic polyol ester is preferably 5 to 30% by weight of the insulating medium.
(8) It is preferable that the kinematic viscosity coefficient at 25 ° C. of the silicone liquid is 50 mm ² / s or less.

  Hereinafter, the present invention will be described in detail with reference to examples.

(Examples 1-5), (Comparative Examples 1-5)
The on-load tap changer 16 is roughly composed of a change-over switch unit 17 and a tap selector unit 18. In Examples 1 to 5, a vacuum switch type on-load tap changer using a vacuum switch was used as the switching switch unit 17. FIG. 2 shows a schematic diagram of the vacuum switch type on-load tap changer. 1 and 2, a transformer in which a primary winding 3 and a secondary winding 4 are wound around an iron core 2 is housed in a tank 1 that houses a liquid insulation / cooling medium. The winding is inserted into the insulating cylinder 5. The iron core 2 is firmly fastened by insulators 11, 12, 13, and 14 at the upper and lower ends of the windings and the fasteners 10a and 10b. In the LTC chamber, dry air using a breather, or for the purpose of disaster prevention, the LTC chamber is a sealed space that is cut off from the outside air, and an inert gas (nitrogen gas, SF6 gas, CF3I gas) is enclosed.

  When the switching switch unit 17 is a vacuum switch, it is not necessary to enclose an insulating / cooling medium in the switching switch unit.

  A circuit diagram when a vacuum switch is used as a switching switch is shown in FIG. In the figure, vacuum switches 22a and 22b are accommodated in a switching switch unit 17a, and vacuum switches 22a and 22b and a current limiting resistor 21 are connected in series, and a tap switching unit 18 and a tap winding 20 are connected to them. Connected in parallel.

  FIG. 3 shows a schematic configuration of a resistive load tap changer as a switch part, and an insulating / cooling medium 19a is enclosed in a tank of the change switch part 17b. The contact is opened and closed between the movable arc contact 24 and the fixed arc contact 23. Other configurations are substantially the same as those shown in FIG. However, in the case of FIG. 3, since an arc may be generated when the contact is opened and closed, the insulation / cooling medium 19a is required to have arc resistance.

  With respect to the transformer, the insulation / cooling medium is circulated using the cooling pipes 9a and 9b. The medium 6 is heated from the upper part of the tank and drawn out, and the medium cooled by the cooler 8 is returned to the tank through a pipe 9b below the tank.

  An oil passage 15 is provided in the central portion of the iron core 2, and the cooled medium ascends the oil passage while cooling the iron core.

  The tap selector portion is filled with an insulating medium 19. As the insulating medium, a silicone liquid in which a polyol ester is mixed (dissolved) is used. The polyol ester to be mixed is synthesized from a polyhydric alcohol and a monovalent fatty acid, and is excellent in thermal stability and hydrolysis resistance. A hindered type is preferred.

  Examples of the polyhydric alcohol include neopentyl glycol, trimethylolpropane, and pentaerythritol. Monovalent fatty acids include pentanoic acid, hexanoic acid, heptanoic acid, octanoic acid, 2-methylbutanoic acid, 2-methylpentanoic acid, 2-methylhexanoic acid, 2-ethylhexanoic acid, isooctanoic acid, 3, 5, 5 -There are trimethylhexanoic acid and the like, and one or more of them can be used.

In the present invention, a polyol ester represented by the formula (1), (2), (3) and / or (4) having at least two ester groups in the molecule is used. Formula (1) is neopentyl glycol polyol ester, Formula (2) is trimethylolpropane polyol ester, Formula (3) is pentaerythritol polyol ester, and Formula (4) is dipentaerythritol polyol ester. These polyol esters may be used alone or in combination of two or more. The amount of the polyol ester in the insulating medium 19 is more preferably 5% by weight or more and 10% by weight or more. If it is less than 5% by weight, sufficient lubrication characteristics cannot be obtained, and even if it is added in an amount of 30% by weight or more, no significant improvement in lubrication characteristics is observed. On the other hand, since the heat of combustion of polyol ester is larger than that of silicone liquid, it is better to add as little polyol ester as possible. Accordingly, the amount of the polyol ester is preferably 30% by weight or less, and more preferably 20% by weight or less.
On the other hand, the silicone liquid is preferably a dimethyl silicone represented by the formula (5) or a methylphenyl silicone liquid represented by the formula (6).

  A material having a flash point exceeding 250 ° C. is used as the insulating medium, and it is preferable that the flash point exceeds 250 ° C. for both the silicone liquid and the polyol ester to be mixed.

  The insulating medium 19 may be mixed with an antioxidant, an acid scavenger, an antifoaming agent, a metal deactivator, and the like. In Examples 1 to 5 and Comparative Examples 1 to 5, Table 1 shows insulating media used for the tap selector section.

In Examples 1 to 5, all of the insulating media used in the tap selector section had a flash point exceeding 250 ° C. and a volume resistivity of 1.0 × 10 ¹³ Ω · cm or more at 80 ° C. It was found to have characteristics. Moreover, it turns out that the lubrication characteristic is also excellent.

  When a vacuum switch is used as the tap switch part of the tap switch, the arc and the cooling medium do not come into contact with each other. Therefore, an arc of the switching switch is generated in the vacuum part inside the vacuum valve, but no arc is generated outside the vacuum valve. It has a structure. In addition, it is preferable to use a silicone liquid as an insulating / cooling medium sealed in a tank containing an induction device such as a transformer, but other insulating / cooling medium such as mineral oil can also be used. However, this configuration is not preferable for incombustibility.

In Comparative Examples 1 and 2, two types of dimethylsilicone liquids having different viscosities were examined as insulating media used in the tap selector section, but the flash point exceeded 250 ° C. and the volume resistivity was 1.0 × at 80 ° C. Although it was 10 ¹³ Ω · cm or more, sufficient lubrication characteristics were not obtained.

  In Comparative Examples 3 and 4, methyl ricinoleate, which is a linear fatty acid ester represented by Formula (7), and a fatty acid ester of glycerin represented by Formula (8) were examined. Although 5% by weight of the ester was mixed with respect to the total amount of the insulating medium, only 2% by weight of methyl ricinoleate was dissolved, and the total amount (5% by weight) of the fatty acid ester of glycerin was not dissolved. The methyl ricinoleate and the fatty acid ester of glycerin represented by the formula (8) did not dissolve up to 5% by weight with respect to the insulating medium mainly composed of silicone liquid, and sufficient lubrication characteristics were not obtained.

  As described above, by using a vacuum switch as a load tap changer, non-flammability can be achieved by preventing an arc from being generated in the medium, and as an insulating medium for the tap selector section. A synthetic polyol ester represented by the formula (1), (2), (3) and / or (4) having a flash point exceeding 250 ° C. (wherein R1 is hydrogen or an alkyl group having 1 to 3 carbon atoms) , R2 is filled with a silicone liquid mixed with one or more alkyl groups having 5 to 12 carbon atoms), thereby satisfying the insulating characteristics and sliding characteristics required for the tap selector section and improving fire resistance. be able to.

(Examples 6 to 9)
In Examples 6-9, in the transformer with a load tap changer which is one embodiment of the present invention of FIG. 1, a resistive load tap changer using a current limiting resistor as the switching switch unit 17 is provided. Using. A schematic diagram of a resistive load tap changer is shown in FIG. In the resistive load tap changer, an insulating medium 19 a is used for the change-over switch unit 17. In Examples 6 to 9, polyol ester oil was used as an insulating medium in the tap selector section. Table 2 shows the insulating medium used for the tap selector section, and Table 3 shows the insulating medium used for the switching switch.

In Examples 6 to 9, all of the insulating media used in the tap selector section had a flash point exceeding 250 ° C. and a volume resistivity of 1.0 × 10 ¹³ Ω · cm or more at 80 ° C. It can be seen that it has characteristics. It was also found that the lubricating properties were excellent.

In addition, all the insulating media used for the switching switch part have a flash point exceeding 250 ° C. and a volume resistivity of 1.0 × 10 ¹³ Ω · cm or more at 80 ° C., and have sufficient insulating properties. Recognize.

(Example 10), (Comparative Examples 5 to 9)
The flammability of the insulating medium was evaluated by the cone calorimeter method. Table 4 shows the results of measuring the maximum heat generation rate when each insulating medium was loaded with a radiant heat amount of 50 kW / m ² .

  It can be seen that the maximum exotherm rate of the synthetic polyol ester is lower than that of the mineral oil, and the maximum exotherm rate of the silicone liquid is even lower.

  As an example, Table 4 shows the results of measuring the maximum heat generation rate of a system obtained by adding 10% by weight of a pentaerythritol-based branched-chain mixed fatty acid ester C to a dimethyl silicone liquid. Reflecting the flame retardancy of dimethyl silicone fluid, it can be seen that the maximum heat generation rate is very small.

  Since the maximum heat generation rate is considered to be almost the same depending on the type of the synthetic polyol ester, it is considered that the maximum heat generation rate of the system in which the synthetic polyol ester is added to the silicone liquid is not significantly different from the values in Table 4.

  As described above, the polyol ester represented by the formula (1), (2), (3) and / or (4) whose flash point exceeds 250 ° C. as an insulating medium of the tap selector section (wherein R1 Is required for the tap selector part by filling a silicone liquid mixed with hydrogen or any one or more of alkyl groups having 1 to 3 carbon atoms, and R2 is any one or more of alkyl groups having 5 to 12 carbon atoms. Insulating properties and sliding properties can be satisfied, and fire resistance can be improved.

  TECHNICAL FIELD The present invention relates to a static inductor containing a silicone liquid, which includes a tap changer at load and uses a silicone liquid as an insulating / cooling medium, and relates to a method for improving fire resistance, arc resistance, and sliding characteristics. It can be applied to electrical equipment using silicone fluid such as an input transformer.

It is an embodiment of the present invention, satisfies the insulation characteristics and arc resistance required for the switching switch part, and satisfies the insulation characteristics and sliding characteristics required for the tap selector part, and has excellent fire resistance. Schematic of transformer with silicone liquid with tap changer at load. The schematic diagram of the tap switch at the time of the vacuum switch type load to which this invention is applied. The schematic diagram of the tap switch at the time of resistance type to which this invention is applied.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Tank, 2 ... Iron core, 3 ... Primary winding, 4 ... Secondary winding, 5 ... Insulation cylinder, 6 ... Insulation cooling medium, 7 ... Nitrogen, 8 ... Cooler, 9a, 9b ... Cooling piping, 10a, DESCRIPTION OF SYMBOLS 10b ... Fastener, 11, 12, 13, 14 ... Insulator, 15 ... Oil guide, 16 ... Tap selector at load, 17, 17a, 17b ... Switching switch part, 18 ... Tap selector part, 19, 19a DESCRIPTION OF SYMBOLS ... Insulation medium, 20 ... Tap winding, 21 ... Current limiting resistor, 22a, 22b ... Vacuum switch, 23 ... Fixed arc contact, 24 ... Movable arc contact.

Claims (6)

  A tank, an electromagnetic induction device housed in the tank with a liquid insulator having a flash point exceeding 250 ° C., and a load tap changer for adjusting a voltage of the electromagnetic induction device, the load tap changer Comprises a switching switch part and a tap selection part, and at least as an insulating medium of the tap selector part, a flash point of a synthetic polyol ester having a flash point exceeding 250 ° C. at a rate of 5 to 30% by weight of the insulating medium weight. A static induction appliance with a tap changer at the time of use, characterized in that is dissolved in a silicone liquid exceeding 250 ° C. A tank, an electromagnetic induction device housed in the tank with a liquid insulator having a flash point exceeding 250 ° C., and a load tap changer for adjusting a voltage of the electromagnetic induction device, the load tap changer Comprises a switching switch and a tap selector, and at least as an insulating medium of the tap selector, a silicone liquid having a flash point of more than 250 ° C. is represented by the formula (1), formula (2), formula (3) and formula With a load tap changer characterized by using one or more synthetic polyol esters selected from the group represented by (4) dissolved in a proportion of 5 to 30% by weight of the total amount of the insulating medium Static induction machine.
(R 1 —CH ₂ ) ₂ —C— (CH ₂ —O (CO) —R ₂ ) ₂ ... (1) R 1 —CH ₂ —C— (CH ₂ —O (CO) —R ₂ ) _3. equation _{(2) C- (CH 2 -O} (CO) -R2) 4 ···· formula _{(3) (R2- (CO)} O-CH 2) 4 -CH 2 -O-CH 2 - C— (CH ₂ —O (CO) —R ₂ ) ₄ ... Formula (4)
(Wherein R1 is hydrogen or an alkyl group having 1 to 3 carbon atoms, and R2 is one or more of an alkyl group having 5 to 12 carbon atoms) 3. The static induction appliance with a tap switching device when loaded according to claim 1, wherein the switching switch is a vacuum switch. 3. The static induction electric appliance with a tap switching device when loaded according to claim 1, wherein the silicone liquid is at least one selected from the group consisting of silicones represented by the following formulas (5) and (6): .

3. The static induction appliance with a tap switching device when loaded according to claim 1, wherein the silicone liquid has a kinematic viscosity coefficient at 25 [deg.] C. of 50 mm < ² > / s or less. The static induction | guidance device with a tap switching apparatus at the time of a load in any one of Claims 1-5 whose compounding ratio of the said synthetic polyol ester is 10 to 20 weight%.

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