FZW-40.5 Outdoor High-Voltage Vacuum Load Break Switch Thomas Electric

Product Overview

The FZW-40.5 is a three-pole outdoor vacuum load break switch developed for 40.5 kV, 50 Hz overhead distribution networks. It makes and breaks load current under normal operation and also breaks the capacitive charging current of overhead lines, cable lines and capacitor banks within a defined distance. Each pole combines a vacuum interrupter with a visible isolating gap, so load breaking and disconnecting are performed by one compact unit that provides sectioning, isolating, connecting and changeover functions for urban and rural networks, railways and petrochemical plants.

Product Display

FZW-40.5 Outdoor High-Voltage Vacuum Load Break Switch - display

FZW-40.5 Outdoor High-Voltage Vacuum Load Break Switch - poster_display

Model Designation

FZW-40.5 Outdoor High-Voltage Vacuum Load Break Switch - model

Model format: FZW□-40.5/1250-25

FZW – outdoor vacuum load break switch
□ – design sequence number
40.5 – rated voltage, kV
T – spring operating mechanism
1250 – rated current, A
25 – rated short-time withstand current, kA
Other current and withstand-current combinations are available on request

Service Conditions

Altitude: not more than 2000 m
Ambient temperature: -30 ℃ to +40 ℃
Wind speed: not more than 35 m/s
Relative humidity: daily average ≤ 95%, monthly average ≤ 90%
No frequent severe vibration

Construction

Three poles are carried on a galvanized steel frame with red composite insulator columns. Each pole pairs a vacuum interrupter with a serial isolating gap, giving visible isolation in the open position, and a side-mounted CJ□-10XJG cabinet houses the spring operating mechanism; the frame base suits both structure-mounted and pole-mounted installation.

Under load the arc is extinguished in the vacuum interrupters and the isolating blades then open to leave a visible safety gap. Type tests and long-term trial operation confirm high breaking capacity, long electrical endurance, suitability for frequent operation and low maintenance on feeder sectioning, isolation and supply-route changeover duty.

Technical Data

No.	Item	Unit	Parameter
1	Rated voltage	kV	40.5
2	Rated frequency	Hz	50
3	Rated current	A	1250
4	Rated active load breaking current	A	1250
5	Rated closed-loop breaking current	A	1250
6	5% rated active load breaking current	A	62.5
7	Rated cable charging breaking current	A	25
8	1 min power-frequency withstand voltage (vacuum gap / phase-to-phase and phase-to-earth / isolation gap)	kV	68/95/110
9	Lightning impulse withstand voltage (phase-to-phase and phase-to-earth / isolation gap)	kV	185/215
10	Rated short-time withstand current (thermal stability)	kA	25
11	Rated short-circuit duration	s	4
12	Rated peak withstand current (dynamic stability)	kA	63
13	Rated short-circuit making current	kA	63
14	Mechanical life	operations	10000
15	Permissible contact wear of vacuum interrupter	mm	0.6
16	Manual operating torque	Nm	≤300

Selection note: State the rated voltage (standard 40.5 kV, 50 Hz for overhead networks) and the rated current (standard 1250 A, with active load and closed-loop breaking currents equal to the rated current). Confirm the charging-current duty up to 25 A, the 5% active load breaking current of 62.5 A, the short-time duty of 25 kA for 4 s with 63 kA peak, and the site altitude within 2000 m.

Standards

The product conforms to GB 3804 and the applicable IEC standards for high-voltage load break switches, and the design is type tested and verified by long-term trial operation, confirming high breaking capacity, long electrical endurance, suitability for frequent operation and low maintenance.

Technical note: Where user data go beyond the ranges in the technical table, rated current, breaking duties and operating mechanism configuration can be customised by agreement between manufacturer and purchaser; final parameters are subject to nameplate data and the approved specification.

Installation & Dimensions

Installation Diagram

Level the frame on a steel structure or pole platform with the base fully bolted, and connect the earthing terminal to the earth grid with a dedicated conductor. Check three-pole simultaneity, the contact travel of the vacuum interrupters and isolating blades, smooth charge and release of the spring mechanism, and manual operating torque within 300 Nm. Before energisation run the power-frequency withstand check on the main circuit and verify the terminal markings against the approved outline drawing.

Safety notice: Installation, operation and maintenance must be performed by qualified professionals. Before maintenance open the switch, confirm the visible isolating gap on all three poles and earth both sides of the work section. Never operate under fault current, and check the spring mechanism energy state before manual operation.

FAQs

It is used on 40.5 kV overhead distribution networks to make and break load current, to break the capacitive charging current of overhead lines, cables and capacitor banks within a defined distance, and to provide sectioning, isolating, connecting and changeover functions with a visible isolation gap in the open position.

The FN3-12 and FN5-12 are indoor 12 kV load break switches for switchgear cells and indoor substations. The FZW-40.5 is an outdoor 40.5 kV unit for overhead lines, with composite insulator columns, a weatherproof spring operating cabinet and an integrated visible isolating gap in each pole.

FZW denotes an outdoor vacuum load break switch, the box the design sequence number, 40.5 the rated voltage in kV, T the spring operating mechanism, 1250 the rated current in amperes and 25 the rated short-time withstand current in kA. Other current and withstand combinations are available on request.

It breaks and makes the rated active load and closed-loop current of 1250 A, 5% rated active load current of 62.5 A, and cable or capacitor bank charging currents up to 25 A. It is not intended for breaking fault currents, so short-circuit protection must be provided by upstream devices or fuses.

The 1 min power-frequency withstand voltage is 68 kV across the vacuum gap, 95 kV phase-to-phase and phase-to-earth, and 110 kV across the isolation gap, with lightning impulse withstand of 185/215 kV. The short-time withstand current is 25 kA for 4 s, with 63 kA peak withstand and making current.

Yes. Where the duty data exceed the ranges in the technical table, or the site is above 2000 m altitude or outside the standard humidity, temperature and wind conditions, rated current, breaking duties and mechanism configuration can be adapted by agreement between manufacturer and purchaser, subject to the approved specification.

FZW-40.5 Outdoor High-Voltage Vacuum Load Break Switch