JPS6286681A - Molding method for cross-linked polyethylene insulated power cable connections - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

Detailed Description of the Invention (Industrial Field of Application) The present invention relates to cross-linked polyethylene insulating capacitor C below CV
This invention relates to a method of molding an insulating reinforcing layer of a connection part (referred to as a cable).

(Prior art) As a method of molding a reinforcing insulating layer at the connection portion of a Cv cable, an uncrosslinked polyethylene tape containing a crosslinking agent is wound around the conductor connection portion of the cable, or an uncrosslinked polyethylene tape containing a crosslinking agent is wrapped around the conductor connection portion of the cable. A reinforcing insulating layer formed by extruding a polyethylene resin composition was placed inside a mold tube, and was pressurized and heated from the outside to crosslink it and mold it into one piece.

FIG. 2 is an explanatory diagram showing the upper half of the conventional molding method. In the drawing, (C) is a CV cable, (1) is a cross-linked polyethylene insulation layer, ■ Conductor, 1
(3) is a conductor connection sleeve. Conductor connection sleeve (
A reinforcing insulating layer (Φ) is provided over the end of the cross-linked polyethylene insulating layer (4) on the conductor connection part connected by (3). It is formed either by using a polyethylene tape or by extruding an uncrosslinked polyethylene resin composition containing a crosslinking agent using a separate mold.

The above reinforcing insulating layer (Φ) is included, and a heating heater (
There is a metal molded tube (2I) in which 22) is placed.
Using the heating heater (22) as an M source, the conductor connection sleeve (3) is heated to a predetermined temperature and reinforced with a reinforced camphor (4).
Crosslink and mold. At this time, the inside of the molded tube (2I) is reinforced with insulation V! 5 to 10 to prevent foaming of J(2)
A pressurized atmosphere with an inert gas of about k(/c♂) is created.

(M, problem to be solved) According to the conventional molding method described above, a heater (22) placed inside the mold tube (21) is used as a heat source, and heat from the surface of the connection reinforcing insulating layer (2) is used as a heat source. Because of conduction, there is a problem in that it takes a considerable amount of time to raise the temperature of the conductor connection sleeve (3), which has a large heat capacity, to the temperature required for molding.

(Means for Solving the Problems) The present invention provides a method for molding a Cv cable connection part that solves the above problems. In addition to heating, the molded tube is made of a non-metallic, non-magnetic material f1, and ura or inert gas is used as a pressure heating medium from the outside.

(Example) FIG. 1 is an explanatory diagram showing the upper half of an embodiment of the molding method of the present invention, and the same symbols as in FIG. 2 indicate the same parts.

In this embodiment, a high-frequency branch conductor coil q1 is arranged outside the molded pipe 0D, and a high-frequency branch conductor coil q1 is arranged on the outside of the molded pipe 0D, and the high-frequency branch conductor coil q1 is placed in the length direction or perpendicularly to the cable conductor (2) made of copper or aluminum and the conductor connection sleeve (3). A wave magnetic field is applied, and this magnetic field causes the conductor to generate heat due to eddy current loss, heating it from the inside. At this time, if the mold tube OD is made of metal, the mold tube OD itself is also constructed by induction heating or a set material.

In addition, in order to mold, it is necessary to pressurize the reinforcing insulating layer (4) to prevent foaming at the same time as heating.As the heating element, conventional metal heaters cannot be used in high frequency magnetic fields, so inert gas or silicon The surface of a heating medium such as oil is passed through the mold tube oD to simultaneously pressurize and heat the reinforcing insulating layer (Φ) to be heated from the outside.

As described above, in the present invention, the conductor connection portion is heated by high-frequency induction heating to heat it from the inside, and is also heated from the outside using a pressurized heating medium such as inert gas or oil to crosslink and form the reinforcing insulating layer.

(Effects of the invention) Figure 3 shows 1 54 K V 2000 *”CV
Cape tLt (7) This figure shows the results of the temperature rise time of the conductor sleeve in mold connection, and it can be seen that when using the method (a) of the present invention, molding can be done in 172 hours compared to the conventional method (b).

As described above, according to the molding method of the present invention, since heating is performed from both the outside and the inside (conductor) of the reinforcing insulating layer, the molding time can be significantly shortened.

[Brief explanation of drawings]

FIG. 1 is an explanatory diagram of an embodiment of the molding method of the present invention. Second
The figure is an explanatory diagram of a conventional molding method. FIG. 3 shows the measurement results of molding time. C...CV cable, 1...Crosslinked polyethylene insulation layer, 2...Conductor, 3...Sleeve for connecting conductor, 4...
... Reinforcement insulating layer, ■... Molded tube, +2... Pressure heating medium, 13... High frequency induction coil.

Claims (2)

[Claims] (1) In a molding method in which a connection reinforcing insulating layer formed of an uncrosslinked polyethylene resin composition containing a crosslinking agent is placed in a mold tube, the reinforcing insulating layer is crosslinked by heating under pressure, and molded. Cross-linking characterized in that the conductor connection part is heated by heating to heat it from the inside, the molded tube is made of a non-metallic, non-magnetic material, and oil or inert gas is used as a pressurized heating medium from the outside. Method of molding polyethylene insulated power cable connections. (2) A method for molding a cross-linked polyethylene insulated power cable connection portion according to claim 1, wherein the molded tube is made of a fiber-reinforced plastic material.