A kind of contact double shield structure
[technical field]
The present invention relates to metal enclosed switchgear technical field, a kind of contact place double shield structure with gauze screen particularly in metal enclosed switchgear.
[background technology]
In known existing metal enclosed switchgear, the insulation at its movable contact place general normally to be reached over the ground by the insulation of contact surrounding air or other dielectrics or phase insulation, but because the dielectric strength of air is much smaller than solid insulating material, the dielectric strength therefore around contact usually exists lower and causes the problem that punctures.
[summary of the invention]
The object of the present invention is to provide a kind of contact double shield structure, with solve existing high voltage switchgear movable contact place unreasonable structure and under high voltage condition the poor problem easily punctured of the dielectric such as contact surrounding air insulation.
To achieve these goals, the present invention adopts following technical scheme:
A kind of contact double shield structure, comprises the first fixed contact, the first gauze screen, secondary shielding net, the second fixed contact, solid insulator and ground connection conductive coating; First gauze screen and secondary shielding net are arranged at intervals in solid insulator, cavity is provided with in solid insulator, the first fixed contact and the second fixed contact is interval with in cavity, first fixed contact is by attachment screw and the electrical connection of the first gauze screen, and the second fixed contact is by attachment screw and the electrical connection of secondary shielding net; The periphery of solid insulator is provided with ground connection conductive coating.
The present invention further improves and is: the first gauze screen, the axial distance of secondary shielding net between solid insulator are less than the axial distance between the first fixed contact and the second fixed contact.
The present invention further improves and is: solid insulator adopts homogeneous insulating material to make.
The present invention further improves and is: be provided with the moving contact being electrically connected described second fixed contact in described cavity; Moving contact is tubulose or column.
The present invention further improves and is: the first gauze screen and secondary shielding net are made up of metal or conductive nylon material, and thickness is 1-2mm.
The present invention further improves and is: the equal rounding in termination of the first gauze screen and secondary shielding net.
The present invention further improves and is: the material of ground connection conductive coating is semi-conducting material.
The present invention further improves and is: the material of ground connection conductive coating is electric conducting material.
The present invention further improves and is: insulation gas filled in described cavity.
Compared with prior art, beneficial effect of the present invention is: the present invention proposes a kind of low cost and miniaturized, and at utmost can avoid the double shield structure because accidental discharge causes insulating material to destroy; Gauze screen is connected with fixed contact unit by screw by this shielding construction, wherein movable contact unit to be in two fixed contact unit and to play electrical connection effect, and this double shield structure can reduce greatly by lower the brought internal fault problem of gas-insulated medium dielectric strength.
[accompanying drawing explanation]
View when Fig. 1 is a kind of contact double shield structure moving contact conducting of the present invention;
Fig. 2 invents view when a kind of contact double shield structure moving contact disconnects.
[embodiment]
Below in conjunction with accompanying drawing, the present invention is described in further detail:
As depicted in figs. 1 and 2, a kind of contact double shield structure of the present invention, comprises the first fixed contact 1, first gauze screen 3, secondary shielding net 2, moving contact 4, second fixed contact 5, solid insulator 7 and ground connection conductive coating 8.First gauze screen 3 and secondary shielding net 2 interval are cast in solid insulator 7, cavity is provided with in solid insulator 7, the first fixed contact 1 and the second fixed contact 5 is interval with in cavity, first fixed contact 1 is electrically connected by attachment screw 6 and the first gauze screen 3, and the second fixed contact 5 is electrically connected by attachment screw and secondary shielding net 2.Moving contact 4 is also provided with in cavity; The periphery of solid insulator 7 is provided with ground connection conductive coating 8.First gauze screen 3, the secondary shielding net 2 axial distance D23 between solid insulator 7 is less than the axial distance D1-5 between the first fixed contact 1 and the second fixed contact 5.A kind of insulating material of homogeneous of solid insulator 7 is made.Solid insulator 7 is designed to airtight isolated location or is designed to be provided with for the unit of internal gas by hole.Moving contact 4 is tubulose or column.First gauze screen 3, secondary shielding net 2 are made up of metal or conductive nylon material, and thickness is 1-2mm.The equal rounding in termination of the first gauze screen 3, secondary shielding net 2, to optimize Electric Field Distribution.Ground connection conductive coating 8 can be semi-conducting material or other electric conducting materials.
Refer to shown in Fig. 1, when moving contact 4 moves to position shown in Fig. 1 for closing a floodgate, the first fixed contact 1 and the second fixed contact 5 are interconnected by moving contact 4, form major loop.Now, due to the electrical connection effect of attachment screw, the insulation against ground problem of major loop to ground connection conductive coating 8 formed by the first fixed contact 1, second fixed contact 5 and moving contact 4 is converted into: by the Insulation Problems of the first gauze screen 3, secondary shielding net 2 pairs of ground connection conductive coatings 8 in solid insulator 7.Because the dielectric strength of solid insulator 7 is far above the gas-insulated medium intensity in its internal cavities, therefore, avoid the problem being born most of voltage by the gas-insulated medium in solid insulator 7 cavity.
As shown in Figure 2, when moving contact 4 move to the second fixed contact 5 aligned position after for open position, the major loop formed by the first fixed contact 1, second fixed contact 5 and moving contact 4 disconnects.Now, apply high voltage at the first fixed contact 1 end, due to the electrical connection effect of attachment screw, the high potential of the first fixed contact 1 is introduced in solid insulator 7 with attachment screw by the first gauze screen 3.Therefore, the Insulation Problems of the first fixed contact 1 pair of ground connection conductive coating 8, the solid insulator 7 be converted into by dielectric strength is higher is born, and avoids bearing most of voltage by the gas-insulated medium in solid insulator 7 cavity.