GN22-12/5000A High-voltage Isolating Switch in High-current Cabinet

The GN22-12 disconnector is a high-voltage switching device with a rated voltage of 12kV, suitable for three-phase AC 50Hz indoor installations. Its main function is to connect, cut off or convert circuits under the condition of voltage but no load, and provide a visible and reliable electrical isolation point for equipment that needs power-off maintenance to ensure maintenance safety.

I. Main Features

This disconnector has a novel structural design, adopts a two-step locking method, and has excellent thermal and dynamic stability as well as small operating force. The conductive part is mainly composed of a knife blade and a static contact. The knife blade is composed of two slotted pieces to increase the heat dissipation area, improve the mechanical strength and dynamic stability. The main conductive body adopts T2 copper one-time forming technology, which improves the current carrying capacity. New materials and processes such as epoxy resin insulators and brush plating silver are adopted, with good electrical conductivity, small size and light weight. The outlet terminals are convenient for connecting with vacuum circuit breakers and oil circuit breakers, which can reduce the volume of the switch cabinet and lower the cost.

II. Technical Parameters

The main technical parameters of the GN22-12 series disconnectors are as follows:

Rated voltage: 12 kV

Rated frequency: 50 Hz

Rated current: 1600A, 2000A, 2500A, 3150A, etc.

Rated short-time withstand current (4s): 40 kA (corresponding to 1600A-2000A), 50 kA (corresponding to 2500A-3150A)

Rated peak withstand current: 100 kA (corresponding to 1600A-2000A), 125 kA (corresponding to 2500A-3150A)

Rated insulation level: The power frequency withstand voltage is 42 kV between poles and between pole and ground, and 49 kV at the breaking port; the lightning impulse withstand voltage is 75 kV between poles and between pole and ground, and 85 kV at the breaking port.

The rated current range of this series of products covers 2000A to 6300A, and there are multiple derivative models corresponding to different grounding modes (moving contact side grounding, static contact side grounding and double grounding). The product structural forms include flush-mounted type, wall-passing type, flush-mounted grounding type, wall-passing grounding type, etc.

III. Operating Environment and Operation Requirements

The operating environment must meet the following conditions:

Altitude: No more than 1000m (can be extended to 3000m upon negotiation for special requirements).

Ambient temperature: -30℃ to +40℃.

Relative humidity: The daily average value is not more than 95%, and the monthly average value is not more than 90% (at +25℃).

Seismic intensity: No more than 8 degrees.

The disconnector does not have arc extinguishing capability, and it is strictly forbidden to operate under load. During operation, it must be ensured that the circuit is in a no-load state. It is usually matched with CS6-1, CS6-2 manual operating mechanisms or CX-6Ⅱ electric operating mechanisms. In the power distribution system, it is often used in conjunction with circuit breakers to realize circuit switching or change the system operation mode.

IV. Main Applications

The GN22-12 disconnector is mainly used in high-voltage power distribution systems, and its specific applications include:

Power isolation: Form an obvious disconnecting point between high-voltage maintenance equipment and live equipment.

Switching operation: Cooperate with circuit breakers to change the system operation wiring mode, such as busbar switching in double-busbar circuits.

Connect or disconnect small current circuits

Its design meets the basic isolation requirements of the power system, and has an important impact on the design, construction and safe operation of substations and power plants.