CN204967217U - A connection structure that is used for between oil filled cable and dry -type crosslinked cable - Google Patents

Abstract

The utility model discloses a novel connection structure used between an oil-filled cable and a dry-type cross-linked cable. For the first time, the structure uses GIL pipe busbars for connection, including cable terminal assemblies for connecting cables and busbars, and bushing assemblies for cable or pipe busbar insulation tests. The utility model has the following beneficial technical effects: (1) This solution has a compact structure and greatly reduces the occupied area compared with the traditional connection method; (2) Through this connection structure, the oil-filled cable and the dry cross-linked cable are directly connected to each other. Together, and sealed inside the metal shell, the environment adaptability is strong, and the service life of not less than 30 years can be realized; (3) The connection structure is simple, the on-site construction technology is mature, and the construction period is short; (4) The connection structure provides With a convenient insulation test interface, it is very convenient to conduct insulation tests on GIL pipe busbars, oil-filled cables or cross-linked cables.

Description

A connection structure between oil-filled cables and dry cross-linked cables

technical field

The present invention relates to a connection structure between an oil-filled cable and a dry-type cross-linked cable, more specifically, to a connection structure between an oil-filled cable and a dry-type cross-linked cable realized by using a GIL pipe busbar and a cable terminal assembly .

Background technique

With the rapid development of the plastics industry, cross-linked polyethylene cables that are simple, heat-resistant and have excellent dielectric properties are widely used at home and abroad. In my country's power supply grid, some newly-built power supply lines use cross-linked polyethylene cables, but most of them still use oil-impregnated paper-insulated oil-filled cables. In this way, cross-linked cables and oil-impregnated paper-insulated oil-filled cables will have a longer period of coexistence. Therefore, in the future technical transformation and power cable overhaul, it is necessary to connect the XLPE cable with the original oil-impregnated paper-insulated oil-filled cable. At present, the average lifespan of the outdoor joints of oil-impregnated paper insulated cables is only more than two years, and the failure rate is as high as 7.3%, which has become a weak link in the maintenance of power cables. The service life of the outdoor joints of XLPE cables is between 5 and 10 years, which is lower than the failure rate of oil-filled cables, but it still does not meet the long-term running time requirements required by the State Grid Corporation.

In the case of coexistence of oil-filled cables and cross-linked cables, if you want to directly connect oil-filled cables and cross-linked cables through special joints, domestic manufacturers do not have the technology and performance to produce this joint, only Hong Kong has done related technology and research But there is no product operation experience at present. Due to the different insulation materials used in oil-filled cables and cross-linked cables, it is technically difficult to develop this new product, which requires a relatively long development cycle and high test costs. Moreover, unproven new technologies and adoption may bring greater security risks to the stable operation of the power system.

The connection structure of the present invention uses the GIL pipe bus bar and the component cable terminal of the GIS to be combined together to realize the connection between the oil-filled cable and the dry cross-linked cable. Both GIL and GIS products have a service mission of not less than 30 years, fully meeting the long-term use requirements of users. Moreover, in this connection structure, all the live parts and the connection structure are placed in an inflatable metal casing, and the metal casing is grounded, so that the operation and maintenance personnel have no risk of electric shock. The structure has strong environmental adaptability and compact structure. The key point is to solve the problem of carrying out insulation withstand voltage test on cables.

Contents of the invention

Aiming at the defects existing in the prior art, the object of the present invention is to provide a connection structure between an oil-filled cable and a dry cross-linked cable that is safe, efficient and capable of long-term operation.

In order to achieve the above purpose, the present invention adopts the following technical solution: the GIL closed pipe bus bar with independent air chamber is used as the main connection structure in the middle of the connection structure. Both ends are connected to the cable with cable terminal assemblies (each cable terminal assembly uses an independent air chamber). The conductors connected to the cable head inside the cable terminal assembly have various combination structures. By disassembling and assembling different conductor combinations, reliable Realize the conduction of the conductive loop, the insulation withstand voltage test of GIL components, and the insulation withstand voltage test of oil-filled cables or dry cross-linked cables.

The SF6 monitoring of the gas chamber is led to the inspection height by the gas pipeline.

Compared with the prior art, adopting a new connection structure between the oil-filled cable and the dry cross-linked cable of the present invention has the following beneficial technical effects:

(1) This solution has a compact structure and greatly reduces the footprint of traditional connection methods;

(2) Through this connection structure, the oil-filled cable and the dry-type cross-linked cable are directly connected together and sealed inside the metal shell, which has strong environmental adaptability and can achieve a service life of not less than 30 years;

(3) The connection structure is simple, the site construction technology is mature, and the construction period is short;

(4) This connection structure provides a convenient insulation test interface, and it is very convenient to conduct insulation tests on GIL pipe busbars, oil-filled cables or cross-linked cables.

Description of drawings

Fig. 1 is the structural representation of the embodiment of the present invention;

Fig. 2 is a schematic diagram of the cable insulation withstand voltage test connection structure in Fig. 1;

Fig. 3 is a structural schematic diagram of the insulation withstand voltage test of the GIL pipe busbar in Fig. 1 .

detailed description

The technical solutions of the present invention will be further described below in conjunction with the accompanying drawings and embodiments.

Please refer to Figures 1 to 3 for a connection structure between an oil-filled cable and a dry-type cross-linked cable and an insulation withstand voltage test scheme.

In the middle of the connection structure, the GIL closed pipe busbar with independent air chamber is used as the main connection structure. The length of pipe bus is determined according to engineering needs. Both ends are connected to the cable with cable terminal assemblies (each cable terminal assembly uses an independent air chamber). The conductors connected to the cable head inside the cable terminal assembly have various combination structures. By disassembling and assembling different conductor combinations, reliable Realize the conduction of the conductive loop, the insulation withstand voltage test of GIL components, and the insulation withstand voltage test of oil-filled cables or dry cross-linked cables.

In the normal operation state of the product, as shown in Figure 1, the conductor inside the grounded metal shell is connected to the cable head to realize the operation function of the product.

When the product is installed, it is necessary to conduct an insulation withstand voltage test on the connection structure to ensure the electrical performance of the product. At this time, it is necessary to adjust the conductor connection form in the cable terminal assembly, as shown in Figure 3, disconnect the cable head from the conductor, connect the bushing assembly with the GIL busbar, and apply high voltage to the product through the bushing to achieve insulation Pressure test.

During product installation or regular maintenance, it is generally necessary to conduct an insulation withstand voltage test on the cable. Generally, the voltage is applied through the cable joint. The traditional connection structure is difficult to achieve this function. The solution provided by the present invention solves this problem. Connect the bushing assembly and the cable head through the conductor, disconnect the connection with the GIL busbar at the same time, and apply the test voltage to the cable through the bushing to realize the product test.

The SF6 monitoring of the gas chamber is led to the inspection height by the gas pipeline.

Claims (6)

1. A new connection structure used between oil-filled cables and dry cross-linked cables, characterized in that it includes several lengths of GIL pipe busbars and cable terminal assemblies for connecting cables, and the cable terminal assemblies are installed on the bracket , It is easy to realize that the cable head is loaded into the terminal assembly from the lower end, and the GIL busbar is horizontally connected to the two cable terminal assemblies. The new connection structure also includes a bushing assembly for the insulation test of the cable or pipe busbar. 2. A new connection structure for oil-filled cables and dry-type cross-linked cables according to claim 1, characterized in that this structure is used for the first time in the connection between oil-filled cables and dry-type cross-linked cables , Reduce the environmental requirements for on-site operations, shorten the installation period, and reduce the footprint of the equipment. 3. A new connection structure for oil-filled cables and dry cross-linked cables according to claim 1, characterized in that the plug-in connection structure between the cable head and the bus bar is easy to disassemble and assemble , and through different combination methods, the insulation withstand voltage test of oil-filled cables and dry-type cross-linked cables can be realized, and the insulation withstand voltage test of the intermediate GIL pipe busbar can be carried out. 4. A new connection structure for oil-filled cables and dry cross-linked cables according to claim 1, characterized in that an isolated air chamber structure is used between the GIL pipe busbar and the cable terminal assembly, and the cable terminal The assembly and disassembly operation of the air chamber of the component does not affect the air chamber of the bus bar of the intermediate pipe. 5. A novel connection structure for oil-filled cables and dry-type cross-linked cables according to claim 1, characterized in that, through the gas pipeline, the gas chamber of the GIL pipe busbar and the gas chamber of the cable terminal The density monitoring equipment of SF6 gas is led to the lower part of the equipment, which is convenient for the operation and maintenance personnel to operate. 6. A new connection structure for oil-filled cables and dry-type cross-linked cables according to claim 1, characterized in that, by selecting cable terminal assemblies of different specifications, it can be applied to new and old standards Cable gland size.