FZN16 Indoor Load Break Switch 12kV 31.5kA | High-Voltage Switchgear Equipment for Power Systems | IEC Certified

Product Overview

The FZN16A-12D indoor high-voltage vacuum load break switch and the FZRN16A-12D switch-fuse combination unit are three-phase switching units for distribution networks of 6 to 12 kV at 50 Hz. They control and protect transformers, cables and line sections, and are used in switch stations, distribution rooms, and industrial and commercial substations. The load break switch makes and breaks load current; in the combination unit the circuit is completed with back-up fuses, so the switch breaks load and overload current while the fuse clears short-circuit current, protects the transformer against overload and keeps the equipment from running on two phases after a fuse blows. The unit suits installations that call for an oil-free switch, no overhaul between services and frequent operation.

Product Display

FZN16A-12D Indoor High-Voltage Vacuum Load Break Switch - display

FZN16A-12D Indoor High-Voltage Vacuum Load Break Switch - poster_display

Model Designation

FZN16A-12D Indoor High-Voltage Vacuum Load Break Switch - model

Model format: FZN16A-12D/630 (load break switch) and FZRN16A-12D/125-31.5 (switch-fuse combination unit)

FZN: indoor vacuum load break switch; FZRN: same combined with fuse
16: design sequence number; A: derivative code
12: rated voltage, kV (the unit serves distribution networks of 6 to 12 kV)
D: earthing switch with making capacity
630: rated current, A; 125: maximum rated current of the fuse, A; 31.5: rated short-circuit breaking current, kA
J: motor operation with manual operation; S: manual operation, generally no mark

Service Conditions

Ambient temperature: +40 °C upper, -25 °C lower
Altitude: not more than 1000 m
Relative humidity: daily average not more than 95%, monthly average not more than 90%
Seismic intensity: not more than 8 degrees
Site condition: no fire, explosion hazard, chemical corrosion or violent vibration
Pollution level: II

Construction

The vacuum arc extinction chambers of the three poles stand upright on a common steel frame carried on insulating support columns, which keeps the unit compact and gives it high dynamic and thermal stability. Insulating pull rods and sliders transmit the movement of the mechanism to the contacts, so each closing or opening operation is completed in one stroke and the contact speed is independent of the operator.

The switch has a visible isolation gap, and the earthing switch with making capacity bonds the de-energised side before maintenance. Mechanical interlocks between the load break switch, the earthing switch and the fuse compartment satisfy the five-prevention requirements of switchgear.

The spring mechanism is charged for closing, and a buffer pad absorbs the impact at opening while an auxiliary switch serves the control and signalling circuits. Motor operation with an electric motor and a release device is available, which allows the unit to take part in remote control and to trip on a protective relay signal.

Technical Data

No.	Item	Unit	Value
1	Rated voltage / highest operating voltage	kV	12
2	Rated frequency	Hz	50
3	Rated current	A	630
4	Rated breaking current of active load	A	630
5	Rated closed-loop breaking current	A	630
6	Rated breaking current of 5% active load	A	31.5
7	Rated cable charging breaking current	A	10
8	Rated capacitive breaking current	A	400
9	Rated no-load transformer breaking current	A	No-load current of a 1600 kVA transformer
10	1 min power-frequency withstand voltage, to earth and between phases / across the isolation gap	kV	42/48
11	Lightning impulse withstand voltage, full wave, to earth and between phases / across the isolation gap	kV	75/85
12	Rated short-time withstand current (thermal stability)	kA/s	20/3
13	Rated peak withstand current (dynamic stability)	kA	50
14	Rated short-circuit making current	kA	50
15	Number of breaking operations at rated current	times	10000
16	Mechanical life	times	10000
17	Permissible cumulative wear of the contacts	mm	3
18	Operating torque for opening and closing	N·m/(N)	120 (240)
19	Rated closing operating voltage / current	V/A	~220/0.5
20	Rated opening operating voltage / current	V/A	~220/3

Selection note: the combination unit is drawn with a back-up fuse of up to 125 A and a rated short-circuit breaking current of 31.5 kA, and the chamber breaks the no-load current of a 1600 kVA transformer, so check the magnetising inrush of the transformer against that fuse rating. 20 kA for 3 s with a 50 kA peak withstand and a 50 kA short-circuit making current set the busbar and upstream protection coordination; verify these against the network before ordering.

Standards

The source page does not quote a standard number for this switch. The usual references for indoor high-voltage load break switches are IEC 62271-102 / IEC 60265-1 and GB/T 3804; confirm the applicable edition with the factory when ordering.

Technical note: final parameters are subject to nameplate data and approved specifications.

Installation & Dimensions

Installation Diagram

FZN16A-12D Indoor High-Voltage Vacuum Load Break Switch - installation

The unit is fixed on its base frame in the cubicle. Before energisation, check the closed, open and earthed positions and the interlocks between the load break switch, the earthing switch and the fuse compartment, fit the specified back-up fuse with its striker engaging the release device, and measure the main circuit resistance and the contact travel.

View / dimension	Value (mm)
Phase spacing, adjacent poles	210, marked twice
Front view horizontal	560 and 720 (720 outermost)
Front view vertical steps	280 / 280 / 150
Side view horizontal	490
Side view vertical	665
Marked diagonal dimension	not less than 150

Safety notice: installation, operation and maintenance must be performed by qualified professionals. Before maintenance, open the load break switch, close the earthing switch and verify absence of voltage. Do not use the load break switch alone to interrupt short-circuit current; that duty belongs to the back-up fuse of the combination unit, and a blown fuse is replaced only with the same rated type.

FAQs

It is an indoor three-phase vacuum load break switch for distribution networks of 6 to 12 kV at 50 Hz, used to make and break load current, to isolate the circuit through a visible gap and to earth the de-energised side for maintenance. The FZRN16A-12D combination unit adds back-up fuses so the same frame also clears short-circuit current and protects a transformer.

FZN is the indoor vacuum load break switch, R marks the fuse combination, 16 the design sequence number, A the derivative code, 12 the rated voltage in kV and D the earthing switch with making capacity. 125 is the maximum rated current of the fuse in A and 31.5 the rated short-circuit breaking current in kA. The trailing letter gives the operating mode: J for motor operation with manual back-up, S for manual operation, which is generally left unmarked.

The tabulated family covers 630 A of active load and closed-loop current, 31.5 A of 5% active load, 10 A of cable charging current, 400 A of capacitive current and the no-load current of a 1600 kVA transformer. That range of duties is what distinguishes a unit built for frequent operation from a simple isolator.

Manual operation with a CS6-1 mechanism or direct operation on the switch frame without an additional mechanism is standard. The FZN16A-12-J version adds motor operation with manual back-up, which allows the unit to take part in remote control and to trip on a protective relay signal. The drawing offers front or rear operation for the switch and the earthing switch.

The combination unit is drawn with a back-up fuse of up to 125 A and a rated short-circuit breaking current of 31.5 kA, and the chamber breaks the no-load current of a 1600 kVA transformer. Check the magnetising inrush of the transformer against that fuse rating before ordering, and replace a blown fuse only with the same rated type.

The unit is offered for networks that switch often and for panels that are not opened for maintenance between services. Mechanical life and the number of breaking operations at rated current are both 10000, and the permissible cumulative contact wear is 3 mm. The fuse compartment is interlocked so that a fuse cannot be reached while the circuit is live.

FZN16A-12D Indoor High-Voltage Vacuum Load Break Switch