JP2001189113A - Bipolar integrated coaxial cable - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a bipolar integrated coaxial cable that can be used for bipolar power transmission and monopolar power transmission, and can avoid the defects in cables of the conventional technology in such areas as environmental issues. SOLUTION: This bipolar integrated coaxial cable comprises a central conductor 1 connected to a negative polarity, concentric insulation layers 2, 4, and a second conductor 3 connected to a positive polarity. The inside insulator 2 and the outside insulator 4 are made of the same material, and in relation to the increase in the voltage, thickness of the outside insulator 4 increases by twice the thickness of the inside insulator 2.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] The present invention relates to a bipolar integrated or integrated coaxial cable as described in the preamble of the claims.

[0002]

[Prior art]

HVDC cables come in two forms, either monopolar (monopolar) circuits or bipolar (bipolar) circuits. Monopolar circuits consist of one high voltage cable, and ground, sea or metal return is used to complete the circuit. Bipolar circuits generally consist of two high voltage cables of the same rating but of opposite polarity. Another limitation of prior art cables is that the two cables must be laid very close to each other or contact each other to minimize the magnetic field around the cables. That is. This also increases the complexity of the cable installation.

A cable of the type described is described in EP 0938
102, a center conductor having a negative polarity, a first insulator layer, a second conductor, a second insulator layer, and an outer package are provided.

[0004]

SUMMARY OF THE INVENTION A bipolar integrated coaxial cable according to the present invention can be used for both bipolar and monopolar transmissions, avoiding the disadvantages of the prior art cables such as environmental concerns. This is achieved with the cable according to the invention as defined by the features stated in the claims.

[0005]

BRIEF DESCRIPTION OF THE DRAWINGS The only figure shows a cross section of a cable according to the invention.

The center conductor 1 is concentrically surrounded by several layers, of which the important one is the second
The insulator 2 is surrounded by the conductor 3 of FIG. The second insulator 4 surrounds the second conductor 3 and is surrounded by the lead 5.

[0007] Inside the outer cladding layer 7 is a plastic coating 6 containing reinforcement.

According to the present invention, the first insulator 2 and the second insulator 4 are made of the same material such as a PP thin film. Up to 50 kV with respect to ground, the thickness of both insulators can be the same. However, 50-10
At 0 kV, the thickness of the insulator 4 increases twice as fast as that of the insulator 2. For example, at 100 kV or more with respect to the ground, the thickness of the insulator 4 is twice as large as that of the insulator 2. The loss through insulator 2 is about twice the loss through insulator 4, which affects the thickness of insulator 2.

For the cable according to the invention, the negative polarity is connected to the center conductor 1 and the positive polarity is connected to the second conductor 3. The cable according to the invention further comprises both conductors inside the metallization, both of which are at high voltage and insulated from ground.

The voltage between the center conductor and the outer conductor is twice the sum of the nominal voltages to ground. The thickness of the first insulator 2 can be up to twice the thickness of the insulator 4 between the second conductor 3 and the outer metallization. Because of the rapid increase in cable size, the present invention is primarily aimed at low to medium transmission capacities, such as up to 350-400 MW, and voltages up to about 200 kV.

According to the invention, a cable is obtained which has a rotationally symmetric cross-section which allows both phases to be laid and finally buried in a single operation (campaign) according to the prior art. According to the present invention, it is possible to lay the present invention at a place where the depth is large.

[Brief description of the drawings]

FIG. 1 shows a cross section of a cable according to the invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Center conductor 2 Inner insulator 3 Second conductor 4 Outer insulator 5 Lead covering 6 Plastic covering 7 Outer outer layer

Claims (1)

[Claims] A center conductor connected to a negative polarity (1)
And a concentric insulator layer (2, 4) and a second conductor (3) connected to a positive polarity, wherein the inner insulator (2) and the outer insulator ( And 4) are made of the same material, and the thickness of the outer insulator (4) increases by twice the thickness of the inner insulator (2) with increasing voltage. Cable.