The switchgear is a switchgear with a withdrawable element, with a modular construction principle, in a metal case, with air insulation, ensuring localization of the short circuit arc.
Switchgears are intended for operation as part of switchgears in all types of power stations and substations, as well as at substations of industrial enterprises and the oil and gas complex, electrification of agriculture, transport, railway transport, metro, including traction substations, transformer substations and linear devices for traction power supply voltage 1000 V, regardless of the type of basic insulation, in three-phase alternating current networks with a frequency of 50 Hz, rated voltage 6, 10, 20, 35 kV, with an isolated neutral or grounded through an arc suppressor or resistor..
Advantages
The casing is made of galvanized sheet steel and is made according to a modular construction principle, divided into functional compartments
Two-way maintenance capability
The safety of switchgear operation is ensured by a system of mechanical and electromagnetic interlocks in accordance with the requirements of GOST and PUE
The use of reliable power switches from various manufacturers provides flexibility in making a more profitable technical and economic solution
Observation windows and LED lighting, which do not require replacement during the entire service life, provide the ability to visually monitor the interior space
The switchgear is a housing made of galvanized steel sheet consisting of three modules connected to each other using bolted connections
Rated disconnecting current of power circuit breaker, kA, not less
20; 25; 31.5; 40
20; 25
20; 25; 31.5
Thermal resistance current, kA
20; 25; 31.5; 40
20; 25
20; 25; 31.5
Duration of thermal resistance current flow, s
главных токоведущих цепей
3
Grounding chains
1
Rated current of electrodynamic resistance of the main ones, kA, not less
51; 64; 81; 102
64
51; 64; 81
Rated power of dry auxiliary transformers built into switchgear cabinets, kVA
25; 40
Rated voltage of auxiliary circuits, V
110 ± 6; 220 ± 11
Standards for testing the insulation of main current-carrying circuits with a one-minute voltage frequency of 50 Hz, kV
relative to the ground
32
42
65
85.5
between the contacts of the power
switch
32
42
65
85.5
Standards for testing the insulation of main current-carrying circuits with a lightning impulse voltage of 1.5/50 μs, kV
relative to the ground
60
75
125
190
between the contacts of the power switch
60
75
125
190
Standard for testing the insulation of control circuits and auxiliary circuits with a one-minute voltage of frequency 50 Hz, kV
2
Electrical
insulation resistance
main current-carrying circuits, MOhm, not less
1000
3000
1000
control circuits and auxiliary circuits, MOhm, not less
1
1
1
MTBF, hour
25000
Service life before write-off, years, not less
thirty
Degree of protection according to GOST 14254
IP31
* — with forced ventilation in the cabinet
Design
The design of complete switchgear switchgear uses a modular formation principle, where each module has its own separate housing. The modules are connected to each other using bolted detachable connections, after which the necessary connections of the main and secondary electrical circuits are made.
The main circuit module is divided into two compartments — the busbar compartment and the cable connection compartment. Each compartment has a separate pressure relief valve. A panel with current transformers is installed on the back of the housing. The back closure is removable and consists of two sheets — upper and lower. At the base of the compartment there is a rectangular “window” cut out for introducing cables into the cell. Depending on the number of connected cables, the “window” can be covered with either sheets with cutouts for cables, or blank sheets or with ventilation slots. Along the side walls, two channel-shaped profiles with evenly cut rectangular holes are fixed to the base for installing crossbars with clamps and brackets with zero-sequence current transformers.
The cable connection module is a continuation to the front side of the cable connection compartment of the switchgear main circuit module. The lower part has a design similar to the main circuit module. In the upper part of the module there are holes for installing panels with support insulators and surge arresters. On the front side, the module has a door similar in design to the door of the withdrawable element module.
The low-voltage equipment module is a separate box with a door on the front side, in which all low-voltage switchgear equipment is concentrated. Installed on the top of the complete switchgear.
The valve insert for the withdrawable element module serves to create favorable conditions for convective cooling of the module and the release of arc combustion products during a short circuit.
The trolley of the withdrawable switchgear element has width dimensions from 600 mm to 1000 mm. The trolley moving mechanism has a moving part, on which a power switch or other device is installed, and a stationary part, secured with mechanical latches to the front side of the draw-out element module housing. The fixed part serves as a base relative to which the cart moves, and has a socket for inserting a special handle, the rotation of which carries out the movement. The transformation of the rotational movement of the handle into the translational movement of the trolley is carried out using a screw rod with a multi-start rectangular thread.
The shutter mechanism is an important safety element for switchgear maintenance. It serves to cover the internal cavities of bushings with current-carrying rods when moving the withdrawable element to the control (non-working) position. Curtains are metal sheet structures that move in a vertical direction under the influence of a system of levers. The levers, in turn, are driven by a trolley, which, by moving, forces them to set the curtains in the desired position.
