Double-pole dry air or nitrogen insulated metal closed switch cabinet for high-speed railway

Abstract

The invention provides a double-pole dry air or nitrogen insulated metal closed switch cabinet for a high-speed railway, solving the problems of environment pollution, complex structure and safety in SF6 gas insulation. The switch cabinet is characterized in that a horizontal breaker and a built-in current transformer are installed in a lower gas tank; an insertion and extraction type casing pipe S2 and an insertion and extraction type cable casing pipe S3 are installed in the lower gas tank and under the horizontal breaker and the built-in current transformer; and the connection between an upper gas tank and the lower gas tank can be achieved through an assembly type gas tank to connect a casing pipe. The switch cabinet has the beneficial effects that SF6 gas insulation is replaced by adopting dry air insulation, which is adaptive to the environmentally-friendly requirement; and the installation safety and one-side wiring of the built-in current transformer can be realized by taking a decompression channel as an installation hole without additionally arranging the installation hole on the panel of the cabinet body, thereby reducing the risk of air leakage of the switch cabinet, leading the internal and external electric fields of the product to be more uniform, improving the safety coefficient of the switch cabinet, effectively expanding the number of outlet cable casing pipes and being convenient for a user.

Description

technical field [0001] The invention belongs to the technical field of high-voltage electrical appliances, and in particular relates to a bipolar dry air or nitrogen insulated metal-enclosed switchgear for high-speed railways. Background technique [0002] At present, the switch cabinets with gas-filled metal enclosures used in high-speed rail power supply systems all use SF 6 (sulfur hexafluoride) gas insulation due to SF 6 The gas is one of the greenhouse effect gases that limit emissions under the "Kyoto Protocol", one SF 6 The greenhouse effect of gas molecules is a CO 2 Molecular 29000 times less SF 6 The use and discharge of gas is a means and measure to protect the environment, and SF 6 The gas will decompose and produce corrosive gas at high temperature during discharge, which has serious harmful effects on metals and people. Therefore, the development of 27.5kV bipolar dry air or nitrogen insulated metal-enclosed switchgear for high-speed rail is a kind of envir...

AI Technical Summary

Problems solved by technology

From a structural point of view, there are some problems in the prior art for the 27.5kV bipolar switchgear used in the high-speed rail power supply system: one is to use an external current transformer, that is, the current transformer is located outside the gas box. It is very inconvenient to make and install the cable terminal once on the cable, and it is difficult for the user to construct on site, and the production cost is high; there are also current transformers placed in the switch cabinet, but the current transformer placed in the switch cabinet There are umbrella skirts or vertical skirts on three sides of the bottom of the primary side of the square housing. Due to the existence of umbrella skirts or vertical skirts and the small space in the cabinet, it is very inconvenient to install in the cabinet. In order to stably install the current transformer in the cabinet And to realize the wiring on the primary side, in addition to using the pressure relief channel of the switchgear as a mounting hole, it is also necessary to open corresponding mounting holes on the panel of the switchgear, which will easily cause air leakage in the switchgear and affect the safety of the switchgear performance; the second is that the connection between the two airtight units uses an inner cone busbar bushing. When connecting the two airtight unit busbars, it is necessary to use two inner cone bushings and a plug-in connector for combination. The structure is complex, the axial dimension is large, and the production cost is high. In addition, the sleeve and the plug-in connector are connected by spring contacts, and the contact resistance is large, which limits the conductivity. If it is not concentric, the conductor will tilt, which will affect the working temperature in the cabinet, and the end of the bushing is conical, the electric field is uneven, and it is easy to discharge; the third is that the outlet cable bushing is installed on the upper air box and located in the lower air box. On the rear side, due to the limitation of the space in the cabinet, the number of outgoing cable bushings is limited, which is not conducive to expansion. If the number of outgoing cable bushings needs to be expanded, the depth of the upper gas box needs to be deepened, or multiple switch cabinets should be combined. The former needs to increase the size of the upper air box, and at the same time requires more supports, which will increase the volume of the entire switchgear and increase the production cost; the latter will require multiple switchgears to be combined, requiring more space for installation. and increase user investment

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