JPS6110924B2 - - Google Patents

Description

[Detailed description of the invention] This invention relates to oil-filled electrical equipment.

In recent years, 1-phenyl-1-(dimethylphenyl)ethane (hereinafter simply referred to as PXE; the same applies hereinafter) and alkyl phenyl phosphate (APP) have been used for electrical elements such as capacitor elements.
A variety of oil-filled electrical equipment impregnated with insulating oil, either singly or in combination, have been proposed.

However, even with these insulating oils, there are limits to the ability to make this type of oil-filled electrical equipment more compact or more reliable.

The present invention was proposed in view of the above-mentioned circumstances, and includes an electrical element such as 1-phenyl-2-(1-phenyl-2-( isopropylphenyl)
It is impregnated with a mixed oil of ethane (CPE) and the above-mentioned APP. In addition, APPs include tricresyl phosphate (TCP), tricylenyl phosphate, tri(ethyl phenyl) phosphate (TEP), and tri(isopropylphenyl).
Phosphate, etc.

Attached table 1 shows the characteristics of TCP, TEP and CPE
become that way. For comparison, the characteristics of conventional mineral oil and PXE, which has been used recently, are also shown.

As understood from Attached Table 1, although CPE has a slightly higher flash point than mineral oil, both its pour point and viscosity are lower. In addition, CPE has a lower viscosity than PXE, which has been used recently.

Next, Table 2 shows the interaction characteristics with plastic films, such as polypropylene films (PP films), which have recently been widely used in the construction of thin dielectric layers of capacitor elements in oil-immersed electrical equipment, such as oil-immersed capacitors. become that way. In addition, in Attached Table 2, spread refers to the area where the oil spreads when 0.02 cc of oil is dropped onto a PP film, another PP film is gently dropped on top of it from a height of 2 cm, and 20 minutes have passed since then. . In addition, the characteristic values of swelling property and solubility in the same table are all after being kept at 80°C for 30 days.

It can be seen from Attached Table 2 that CPE has superior spreading properties compared to mineral oil and PXE, and is less likely to swell or dissolve in PP film.

Next, Figures 1 and 2 show the relationship between the mixing ratio (weight %) of mixed oils (TCP + CPE, TEP + CPE), viscosity a and spread b, which are mixtures of TCP and CPE and TEP and CPE. . For comparison, the same figure also shows the viscosity a' and spread b' of mixed oils (TCP+PXE, TEP+PXE), which are a mixture of TCP and PXE and TEP and PXE, as dotted lines. Note that the spread was determined by the method described above.

As understood from Figures 1 and 2,
The mixed liquid of TCP and CPE and TEP and CPE tends to have a higher viscosity and a smaller spreading area as the mixing ratio of TCP or TEP, which is APP, increases.
Compared to a mixed oil of TEP and PXE,
Excellent viscosity and spread.

Next, we will discuss the characteristics of oil-immersed capacitors impregnated with a mixed oil of TCP and CPE and TEP and CPE.

In the following explanation, a paper film capacitor is defined as an 18 μm thick insulating paper (density 0.80 g/
cm ³ ) interposed and wound (capacity 12μ)
F), an all-film capacitor is one in which two sheets of PP film with a thickness of 18 μm are wound as a thin dielectric layer (capacitance: 10 μF).

Example: Paper film capacitor with TCP, OPE and
Samples A ₁ to A ₄ were prepared by impregnating TEP and CPE with mixed oil at the mixing ratio shown in Attached Table 3, and for comparison, TCP and PXE and TEP and PXE were impregnated as shown in Attachment 3. Samples B ₁ to _{B 4} impregnated with mixed oil at a mixing ratio were manufactured.

Figures 3 to 6 show these specimens A ₁ to A ₄ and B ₁ to
For B ₄ , the relationship between the heating time and corona onset voltage (CSV) when heated to 70°C to improve the impregnation effect is shown.

Example Samples A ₅ to _{A 8} were manufactured by impregnating all-film capacitors with mixed oil of TCP and CPE and TEP and CPE in the mixing ratio shown in Attached Table 4.
For comparison, test samples B ₅ to B ₈ were prepared by impregnating them with mixed oils of TCP and PXE and TEP and PXE at the mixing ratios shown in Attached Table 4.

Figures 7 to 10 show the heating time and corona temperature for these test samples A ₅ to _{A 8} and B ₅ to B ₈ when heated to 70°C to improve the impregnating effect, as in the previous example. Indicates the connection with the starting voltage (CSV).

As understood from Figures 3 to 10,
Capacitors (specimen A ₁ to _{A 8} ) impregnated with mixed oil of TCP and CPE and TEP and CPE are as follows:
Compared to capacitors impregnated with a mixed oil of TCP and PXE and TEP and PXE (specimens B ₁ to _{B 8} ), the initial value of CSV immediately after completion was higher;
Furthermore, CSV tends to increase due to short-term heat treatment.

The results are as shown in Figures 1 and 2.
The viscosity of the mixed oil containing APP and CPE and the compatibility (spreading) with the plastic film are
It is superior to the mixed oil that is a mixture of APP and PXE, that is, the mixed oil that is a mixture of APP and CPE can impregnate the entire inside of the capacitor element in a short time, and the inside of the capacitor element can be impregnated. This is thought to be the result of the absence of unimpregnated areas and the excellent properties of the mixed oil of APP and CPE and the plastic film.

Next, we will discuss the characteristics of oil-immersed transformers impregnated with mixed oil of TCP and CPE and TEP and CPE.

Example: Insulating paper is used to insulate the coils of a transformer,
5000KVA impregnated with mixed oil of TCP and CPE and TEP and CPE in the mixing ratio shown in Attachment 5,
Specimens A ₉ and A ₁₀ for 77KV were manufactured, and for comparison, specimens B ₉ and B were impregnated with mixed oil of TCP and PXE and TEP and PXE at the mixing ratio shown in Attached Table 5. ₁₀ and sample impregnated with current mineral oil
I made MO.

In the right column of Attached Table 5, these specimens A ₉ , A ₁₀ ,
CSV at -30°C and 20°C is shown for B ₉ , B ₁₀ and MO.

As understood from Appendix 5, the transformers (specimens A ₉ and A ₁₀ ) impregnated with mixed oil of TCP and CPE and TEP and CPE are the same as those of TCP and PXE and
Compared to transformers impregnated with mixed oil of TEP and PXE or mineral oil (specimens B ₉ , B ₁₀ , MO), the CSV is higher in both the low temperature and normal temperature ranges.

Next, we will discuss the characteristics of oil-filled power cables impregnated with a mixed oil of TCP and CPE and TEP and CPE.

Example: A mixed oil of TCP (50% by weight) and CPE (50% by weight), and a mixture of TEP (50% by weight) and CPE (50% by weight) was applied to an insulated product made by laminating PP film and insulating paper. A voltage 1.5 times the rated voltage was applied to the oil-impregnated power cable at 70°C. The test cables are 2m short, and the number of test products is 10 each.

As a result, 8 tubes impregnated with mineral oil broke down after 100 days, whereas TCP
For those impregnated with a mixed oil containing CPE and TEP and CPE, no breakdown occurred even after 100 days.

As described in detail above, according to the present invention, the insulation characteristics can be improved without hindering the miniaturization of this type of oil-filled electrical equipment, and the reliability thereof can be significantly improved.

Note that this invention is not limited to the above-mentioned embodiments, and various modifications can be made without departing from the spirit thereof. For example, in the case of plastic film, polyethylene terephthalate film, polyethylene terephthalate film, etc. may be used instead of the above-mentioned PP film.
Polycarbonate film etc. can be used, and if we look at mixed oil, it can be used as APP.
A mixed oil may be prepared by mixing CPE with one or more selected from TCP, TEP, tricylenyl phosphate, and tri(isopropylphenyl) phosphate, or an epoxy compound or phenol may be added to this mixed oil. A small amount (0.5% to 7% by weight) of one or more of system stabilizers or amine stabilizers
% by weight) may of course be added.

Also, the mixing ratio of APP and CPE varies depending on the use and rating of the oil-filled electrical equipment, but
If the mixing ratio is 40% by weight or more, the viscosity will be slightly higher, but this type of oil-filled electrical equipment can be made flame retardant.

[Brief explanation of the drawing]

Figures 1 and 2 are diagrams showing the relationship between the mixing ratio of the mixed oil used in this invention, viscosity, and spread, and Figures 3 to 10 are diagrams showing the relationship between the heating time and the oil-immersed condenser according to the embodiment of this invention. FIG. 3 is a characteristic diagram showing the relationship with corona starting voltage. _A1 to _A8 : Characteristic curve diagrams according to examples of the present invention, _B1 to _B8 : Characteristic curve diagrams according to comparative examples.

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Claims (1)

[Scope of Claims] 1. An oil-filled electrical device characterized in that an electrical element is impregnated with a mixed oil of alkyl phenyl phosphate and 1-phenyl-2-(isopropylphenyl)ethane. 2. The oil-filled electrical equipment according to claim 1, wherein the electrical element has an insulator, and the insulator is insulating paper. 3. The oil-filled electrical equipment according to claim 1, wherein the electrical element has an insulator, and the insulator is a synthetic resin film. 4 Claim 1 in which the electric element has an insulator, and the insulator is insulating paper and synthetic resin film.
Oil-filled electrical equipment as described in section. 5. The oil-filled electrical equipment according to claim 3 or 4, wherein the synthetic resin film is a polypropylene film.