Electrical insulating oil composition

• US 5,015,793 A
• Filed: 09/04/1987
• Issued: 05/14/1991
• Est. Priority Date: 09/04/1986
• Status: Expired due to Term

• Current Assignee: Nippon Petrochemicals Co., Ltd. (ENEOS Holdings, Inc.)
• Original Assignee: Nippon Petrochemicals Co., Ltd. (ENEOS Holdings, Inc.)
• Inventors: Sato, Atsushi, Endo, Keiji, Kawakami, Shigenobu, Dohi, Hideyuki
• Primary Examiner(s): Pal, Asok
• Application Number:
  US07/093,803
• Time in Patent Office: 1,348 Days
• Field of Search: 585/6.3, 585/6.6, 585/24, 585/25, 361/315, 361/323, 361/327, 252/570
• US Class Current: 585/6.3
• CPC Class Codes: H01B 3/22 hydrocarbons
• CPC Class Codes: H01B 3/44 vinyl resins; acrylic resins silicones H01B3/46
• CPC Class Codes: Y10T 29/43 Electric condenser making

Abstract

An electrical insulating oil composition having good low temperature characteristics which comprises at least 4 members selected from the group consisting of (a) m-ethylbiphenyl, (b) p-ethylbiphenyl, (c) o-benzyltoluene, (d) m-benzyltoluene, (e) p-benzyltoluene, (f) 1,1-diphenylethane, and (g) 1,1-diphenylethylene; and is characterized in that the proportion of solid phase at a temperature of -40° C. of the electrical insulating oil composition is not more than 45% by weight and the proportion of the total quantity of solid phase is calculated according to the following general equation of solid-liquid equilibrium: ##EQU1## wherein X_i is the equilibrium mole fraction of a component i in the liquid phase of the composition, ΔH_i^f is the heat of fusion (cal.mol^-1), T_i^f is the melting point (K), t is the temperature (K), and R is the gas constant (cal.mol^-1.K^-1).

Claims

1. An electrical insulating oil composition having good low temperature characteristics which composition comprises at least 4 members selected from the group consisting of the following 7 components:

(a) m-ethylbiphenyl,

(b) p-ethylbiphenyl,

(c) o-benzyltoluene,

(d) m-benzyltoluene,

(e) p-benzyltoluene,

(f) 1,1-diphenylethane, and

(g) 1,1-diphenylethylene

and is characterized in that the proportion of solid phase at a temperature of -40°

C. of said electrical insulating oil system is not more than 45% by weight and the proportion of the total quantity of solid phase is calculated according to the following general equation of solid-liquid equilibrium;

##EQU3## wherein X_i is the equilibrium mole fraction of a component i of said 7 components in the liquid phase of said composition,

Δ

H_i^f is the heat of fusion (cal.mol^-1) of said component i as a pure substance,

T_i^f is the melting point (K) of said component i as a pure substance,

T is the temperature (K) of the system, and

R is the gas constant (cal.mol^-1. K^-1).

2. The electrical insulating oil composition as claimed in claim 1, wherein said temperature of the system is -50°

C.

3. An oil-filled electrical capacitor which is impregnated with an electrical insulating oil composition having good low temperature characteristics;

said composition comprises at least 4 members selected from the group consisting of the following 7 components;

(a) m-ethylbiphenyl,

(b) p-ethylbiphenyl,

(c) o-benzyltoluene,

(d) m-benzyltoluene,

(e) p-benzyltoluene,

(f) 1,1-diphenylethane, and

(g) 1,1-diphenylethylene

and is characterized in that, the proportion of solid phase at a temperature of -40°

C. of said electrical insulating oil system is not more than 45% by weight and the proportion of the total quantity of solid phase is calculated according to the following general equation of solid-liquid equilibrium;

##EQU4## wherein X_i is the equilibrium mole fraction of a component i in the liquid phase of said composition,

Δ

H_i^f is the heat of fusion cal.mol³¹

     1) of said component i as a pure substance,

T_i^f is the melting point (K) of said component i as a pure substance,

T is the temperature (K) of the system, and

R is the gas constant (cal.mol^-1.K^-1).

4. The oil-filled electrical capacitor according to claim 3, wherein said capacitor has a rolled plastic film.

5. The oil-filled electrical capacitor according to claim 4, wherein said plastic film is a polyolefin film.

6. The oil-filled electrical capacitor according to claim 5, wherein said polyolefin film is polypropylene film.