FKN12-12RD/630A wall-mounted high-voltage load switch, 10KV fuse combination load switch

The FKN12 series load switch is a combined high-voltage switchgear with a rated voltage of 12kV and a frequency of 50Hz. It is mainly used in power systems for scenarios such as making and breaking load currents, controlling no-load transformers, and operating overhead lines.

I. Main Models and Functions

This series includes two main models:

FN12-12D/630-20 indoor AC high-voltage load switch: With a rated current of 630A, it has the ability to make and break load currents, closed-loop currents, no-load transformers and cable charging currents, and can close short-circuit currents. Equipped with a grounding switch, it can withstand short-circuit currents.

FN12-12R.D/100-31.5 (or FKRN12 series) indoor high-voltage load switch-fuse combination device: Combines the load switch and high-voltage current-limiting fuse to realize full-range current breaking. The load switch is responsible for breaking the working current, and the fuse is responsible for breaking the short-circuit current. The two can cooperate to handle any overcurrent between the working current and the short-circuit current.

II. Core Structure and Technical Features

Combined structure: The equipment integrates the load switch, high-voltage current-limiting fuse and mechanism on one frame, with a compact structure.

Breaking method: Adopts a vacuum switch tube or pneumatic design, and the opening and closing adopt a vertical up-down direct movement mode. The arc is extinguished in the bell-shaped insulating cover, which can prevent the reduction of phase-to-phase or ground insulation strength.

Operating mechanism: Adopts a spring energy-storage operating mechanism to ensure stable opening and closing speeds without being affected by operating force. Supports both manual and electric (AC/DC dual-purpose) operation modes.

Safety interlock: Reliable mechanical interlock devices are installed between the load switch, grounding switch and fuse to meet the "five-prevention" requirements for preventing misoperation.

Contact material: Uses copper-tungsten alloy arc contacts and plum-shaped main contacts to enhance conductive reliability and electrical life.

Intelligent functions: Some models have "four-remote" functions such as remote monitoring, data monitoring and fault diagnosis. Built-in multi-functional power quality meters can measure more than 52 power parameters, and are applied to grid-connected new energy power generation fields such as photovoltaic and wind power.

III. Technical Parameters

Rated values: Rated voltage 12kV, rated frequency 50Hz. The rated current of the load switch is 630A, and the rated current of the fuse in the combination device is usually 125A.

Breaking capacity: The rated short-circuit withstand current of the load switch is 20kA, and the rated short-circuit making current is 50kA. The rated short-circuit breaking current of the fuse in the combination device is 31.5kA.

Mechanical performance: Mechanical life of 2000 times, main circuit resistance ≤ 300μΩ.

IV. Application and Environmental Requirements

Main applications: Suitable for 12kV and below three-phase power distribution systems, as control and protection for equipment such as transformers, cables and overhead lines, and is especially suitable for terminal substations, box-type substations and ring network power supply units in urban and rural power grids.

Environmental conditions: The normal working environment temperature ranges from -25℃ to +40℃, and the altitude does not exceed 1000m. The surrounding air should be free of significant corrosive or flammable gas pollution.

Installation requirements: Must be installed vertically, and the switch frame, operating mechanism, cable sheath and other parts shall be reliably grounded (series grounding is prohibited).

V. Matters Needing Attention in Use and Maintenance

The fuse link used in series with the load switch must be properly selected to ensure that the fuse blows first when the fault current exceeds the breaking capacity of the load switch.

Before operation, perform several no-load opening and closing operations to check that there is no jamming in the rotating parts, that the closing is in place, and that there is sufficient safety distance after opening.

During inspection, check for dirt, cracks and discharge on the porcelain bottles, and the switch body cannot be washed with water.

After the fuse is blown and triggers the opening, the three-phase fuses of the same model and specification must be replaced.

The product should be stored indoors with ventilation, dryness and no corrosive gas, and strictly protected from rain and exposure to sunlight.