CN110492425A - A new type of indoor and outdoor terminal for high-voltage power cables - Google Patents

Abstract

The invention discloses a novel indoor and outdoor terminal of a high-voltage power cable. In the invention, the insulating jacket includes an insulating core with a capacitive screen and an outer insulating sleeve arranged outside the insulating core. The insulating core is made of glue Paper-impregnated sleeve or rubber-impregnated fiber sleeve, a uniform coaxial electrode is formed between the capacitive screen in the insulating core and the cable conductor in the power cable. Compared with the traditional structure, the present invention saves the stress cone on the cable and a large amount of insulating oil inside, and has the characteristics of easy on-site operation, excellent electrical performance and high operation reliability; especially its oil-free characteristics, Even if an insulation fault occurs, it will not cause vicious accidents such as explosion and combustion, and is more suitable for use in cities.

Description

A new type of indoor and outdoor terminal for high-voltage power cables

Technical field:

The invention relates to a power transmission and distribution equipment, more specifically refers to the indoor and outdoor terminals of high-voltage power cables, and is suitable for indoor and outdoor terminals of new high-voltage power cables of 110kV and above.

Background technique:

At present, the indoor and outdoor terminals of high-voltage power cables are widely used in urban power transmission and distribution systems to connect high-voltage power cables and overhead lines.

As shown in Figure 4 and Figure 5, the indoor and outdoor terminals of traditional high-voltage power cables are relatively concentrated at the cut-off point of the insulation shielding of high-voltage power cables. The general solution for high-voltage power cables of 110kV and above is to use horns made of semi-conductive materials. The tube is used to improve the electric field distribution at the cutting point of the cable insulation shielding, and its structure is consistent with the principle of the outlet bushing used in GIS.

The insulating medium inside the outlet bushing for GIS is SF6 gas, which has good insulating performance, so the above structure basically meets the electrical requirements. However, SF6 gas is generally not suitable for the internal insulation medium of traditional cable terminals, and only liquid insulating materials such as transformer oil or silicone grease can be used, and its insulation performance is worse than that of SF6 gas. practice to improve the electric field distribution.

Although this method has improved the electric field distribution, the effect on products with high voltage levels, especially 330kV and above voltage levels, is still not obvious enough. A large number of test results and actual operation have also proved this point. Due to partial discharge at the long-term stress cone of some cable terminals, the insulating oil (transformer oil) is cracked, resulting in the explosion of the entire cable terminal.

Invention content:

The present invention provides a novel indoor and outdoor terminal of a high-voltage power cable in order to solve the above-mentioned problems in the prior art.

The technical solutions adopted in the present invention include: a new type of indoor and outdoor terminal for high-voltage power cables. The indoor and outdoor terminals are used to connect high-voltage power cables and overhead lines, including terminal blocks, outgoing line clamps, insulating jackets, bottom plates, and post insulators. and the grounding sleeve, the top of the insulating jacket is connected to the outgoing wire clamp and the terminal, and the outgoing wire clamp is placed inside the insulating jacket, the bottom end of the insulating jacket is connected to the bottom plate, and the post insulator and the grounding sleeve are connected to the bottom plate. The terminal is connected to the overhead line, the insulating jacket includes an insulating core with a capacitive screen and an outer insulating sleeve arranged outside the insulating core, and the insulating core is made of glue-impregnated paper sleeve or glue-impregnated A uniform coaxial electrode is formed between the fiber sleeve, the capacitive screen in the insulating core and the cable conductor in the power cable.

Further, the cross section of the capacitive screen is a stepped parallelogram structure.

Further, the insulating jacket is provided with a mounting flange, the zero screen of the capacitive screen is connected to the cable conductor in the power cable, and the last screen of the capacitive screen is connected to the mounting flange.

Further, the outer surface of the outer insulating casing is injected or fitted with a silicone rubber shed.

Further, a porcelain bushing or a composite insulating cylinder is installed on the outer surface of the outer insulating casing.

Further, measuring terminals are provided on the outer wall of the insulating jacket.

Further, a pressure equalizing cover is provided on the top of the insulating jacket.

Further, the inside of the outer insulating sheath in the insulating sheath is filled with an insulating medium.

The present invention has following beneficial effect:

Compared with the traditional structure, the present invention saves the stress cone on the cable and a large amount of insulating oil inside, and has the characteristics of easy on-site operation, excellent electrical performance and high operating reliability; especially its oil-free characteristics, Even if an insulation fault occurs, it will not cause vicious accidents such as explosion and combustion, and is more suitable for use in cities.

Description of drawings:

Figure 1 is a structural diagram of the present invention.

Fig. 2 is a structural diagram of the capacitive screen in the present invention.

Fig. 3 is a scaled diagram of the capacitive screen in the present invention.

Fig. 4 is a schematic diagram of the structure of the outlet bushing in the prior art.

Fig. 5 is a schematic diagram of the structure of indoor and outdoor terminals in the prior art.

Detailed ways:

The present invention will be further described below in conjunction with the accompanying drawings.

As shown in Fig. 1, the indoor and outdoor terminal of a new type of high-voltage power cable of the present invention is used to connect high-voltage power cables and overhead lines, including terminal 1, outgoing line clamp 3, insulating jacket 4, base plate 8, and post insulator 9 And the grounding sleeve 10, the top of the insulating jacket 4 is connected to the outgoing wire clamp 3 and the terminal 1, and the outgoing wire clamp 3 is placed inside the insulating jacket 4, the bottom end of the insulating jacket 4 is connected to the bottom plate 8, and the post insulator 9 and the grounding The sleeve 10 is connected on the bottom plate 8, and the connection terminal 1 is connected with the overhead line.

The insulating jacket 4 includes an insulating core with a capacitive screen 6 and an outer insulating sleeve 41 arranged outside the insulating core. The insulating core adopts a rubber-impregnated paper sleeve (RIP) or a rubber-impregnated fiber sleeve (RIF) ( It can also be made of other solid insulating sleeves). A uniform coaxial electrode is formed between the capacitive screen 6 in the insulating core and the cable conductor in the power cable.

Referring to FIG. 2 and FIG. 3 , the cross section of the capacitive screen 6 is a stepped parallelogram structure.

The insulating jacket 4 is provided with a mounting flange, the zero screen of the capacitive screen 6 is connected with the cable conductor in the power cable, and the last screen of the capacitive screen 6 is connected with the mounting flange. There is a small gap between the inner diameter of the outer insulating sleeve 41 and the outer diameter of the cable with the outer sheath and the grounding shield net removed, and this gap is vacuumized and injected with insulating paste or other insulating materials after the product is assembled and sealed.

The outer surface of the outer insulating casing 41 is injected or fitted with a silicone rubber shed. Alternatively, the outer surface of the outer insulating casing 41 is installed with a porcelain sleeve or a composite insulating cylinder.

In order to meet the requirements of intelligent grid operation, the insulating jacket 4 can also be provided with measuring terminals 7 for detecting partial discharge of products or as online monitoring.

A voltage equalizing cover 2 is provided on the top of the insulating jacket 4, and the voltage equalizing cover 2 improves the top electric field.

The inside of the outer insulating sheath body 41 of the insulating sheath 4 is filled with an insulating medium 5 .

The purpose of the patent of the present invention is to design and manufacture a cable terminal with a new structure on the basis of the above-mentioned background technology with cross-field innovative thinking, so as to greatly improve its operation reliability and completely solve the above-mentioned problems.

The purpose of the present invention is achieved through the following technical solutions:

1) The invention patent uses the principle of uniform electric field of capacitance, and replaces the original insulating jacket with a rubber-impregnated paper bushing (RIP) or a fiberglass bushing (RIF) with a capacitive screen. The end screen of the capacitive screen of the bushing is connected with the mounting flange and the grounding shield on the jacket, and a uniform coaxial electrode is formed between the end screen and the cable conductor, which shields the mounting flange and the cable grounding shield from the electric field , the capacitance of each electrode is basically the same. According to the principle of equal capacitance design, a stepped parallelogram structure is formed inside and outside. The insulation is forced to equalize due to the effect of capacitance, forming a basically uniform voltage distribution and improving the insulation performance.

2) The main insulation containing the capacitive screen is a solid insulator, which can be a resin-impregnated paper casing (RIP) impregnated with epoxy resin, or a fiberglass casing (RIF) wound with glass filaments, or even other insulating materials pouring body.

3) The capacitive screen solid insulator jacket can be directly injected or fitted with a silicone rubber umbrella skirt, or additionally installed with a porcelain sleeve or a composite insulating cylinder as external insulation.

4) The cable stripped off the sheath and the grounding shielding net passes through the inner hole of the bushing, and there is a small gap between them. After the product is assembled and sealed, the gap is vacuumed and injected with insulating paste. This paste not only has good electrical properties , It is not easy to leak, and it will not burn and explode.

5) The indoor and outdoor terminal of the traditional structure uses a larger stress cone to uniform the internal electric field, so the inner diameter of the insulating jacket is larger and the weight is heavier; the patent of the present invention adopts the insulating jacket with a capacitive screen, and its excellent uniformity Electric field distribution and excellent insulation performance, its compact structure, small size, so the overall light weight, easy to transport and install.

The above is only a preferred embodiment of the present invention, it should be pointed out that for those of ordinary skill in the art, some improvements can also be made without departing from the principle of the present invention, and these improvements should also be regarded as the invention. protected range.

Claims (8)

1. A new type of indoor and outdoor terminal for high-voltage power cables, which is used to connect high-voltage power cables and overhead lines, and is characterized in that it includes terminal blocks (1), outgoing line clips (3), insulating jackets (4 ), bottom plate (8), post insulator (9) and grounding sleeve (10), the top of the insulating jacket (4) is connected with the outgoing wire clip (3) and the terminal (1), and the outgoing wire clip (3) Placed inside the insulating jacket (4), the bottom of the insulating jacket (4) is connected to the base plate (8), the post insulator (9) and the grounding sleeve (10) are connected to the base plate (8), and the terminal (1 ) is connected to the overhead line, characterized in that: the insulating jacket (4) includes an insulating core with a capacitive screen (6) and an outer insulating sleeve (41) arranged outside the insulating core, the insulating The core adopts a glue-impregnated paper sleeve or a glue-impregnated fiber sleeve, and a uniform coaxial electrode is formed between the capacitive screen (6) in the insulating core and the cable conductor in the power cable. 2. The indoor and outdoor terminal of the new high-voltage power cable according to claim 1, characterized in that: the cross section of the capacitive screen (6) is a stepped parallelogram structure. 3. The indoor and outdoor terminal of the new high-voltage power cable according to claim 1, characterized in that: the insulating jacket (4) is provided with a mounting flange, the zero screen of the capacitive screen (6) and the cable in the power cable The conductors are connected, and the last screen of the capacitive screen (6) is connected with the mounting flange. 4. The indoor and outdoor terminal of the new high-voltage power cable according to claim 1, characterized in that: the outer surface of the outer insulating sleeve (41) is injected or fitted with a silicone rubber shed. 5. The indoor and outdoor terminal of the new high-voltage power cable according to claim 1, characterized in that: the outer surface of the outer insulating sleeve (41) is equipped with a porcelain sleeve or a composite insulating cylinder. 6. The indoor and outdoor terminal of the new high-voltage power cable according to claim 1, characterized in that: the outer wall of the insulating jacket (4) is provided with a measuring terminal (7). 7. The indoor and outdoor terminal of a new type of high-voltage power cable according to claim 1, characterized in that: a pressure equalizing cover (2) is provided on the top of the insulating jacket (4). 8. The indoor and outdoor terminal of the new high-voltage power cable according to claim 1, characterized in that: the inner and outer insulating sleeves (41) of the insulating jacket (4) are filled with insulating medium (5).