China FZ(R)N21C-40.5D AC Indoor High-Voltage Vacuum Load Switch Supplier, Companies

The FZ(R)N21C-40.5D is an indoor high-voltage vacuum load switch designed for 40.5kV wind and photovoltaic power systems. Integrating multiple functions into one compact unit, it features reliable vacuum arc-extinguishing technology. With rated currents from 630A to 1250A and 25kA short-time withstand capacity, this modular switch offers complete protection with optional current-limiting fuses. Its robust construction ensures stable performance in harsh conditions including cold, humid, and polluted environments. Ideal for substations and distribution networks, this load switch provides safe operation with minimal maintenance requirements for renewable energy applications.

Product Description

Type & Meaning
CJX2-D-4
1 Vacuum load switch
2 R: With fuse base
3 Indoor
4 Design serial number
5 Rated voltage (kV)
6 D: With grounding switch
7 T: Spring operating mechanism
8 Maximum rated current of fuse (A)
9 Rated short-circuit breaking current of fuse (kA)
Normal Service Conditions

a) Ambient temperature: maximum +65°C, minimum -40°C;

b) Ambient humidity: Daily average relative humidity ≤ 95%, monthly average relative humidity ≤ 90%; Daily average vapor pressure ≤ 2.2 kPa, monthly average vapor pressure ≤ 1.8 kPa;

c) Altitude: not exceeding 4000 meters;

d) Seismic intensity: not exceeding 8 degrees;

e) Installation site free from fire and explosion hazards;

f) Ambient air not significantly polluted by dust, corrosive or flammable gases, vapors, or salt mist.

Note: Requirements beyond normal service conditions shall be negotiated with the manufacturer.

Product Display
Technical Parameters

4.1 The main technical parameters of the load switch are shown in Table 1.

No. Parameter Unit Load Switch Combination Apparatus
1 Rated Frequency Hz 50
2 Rated Voltage kV 40.5
3 Power Frequency Withstand Voltage (1 min) Phase & Earth / Vacuum Gap kV 95 Note *
Isolation Gap kV 118 Note *
4 Rated Lightning Impulse Withstand Voltage (Peak) Phase & Earth / Vacuum Gap kV 185 Note *
Isolation Gap kV 215 Note *
5 Auxiliary & Control Circuit Power Frequency Withstand Voltage (1 min) kV 2
6 Rated Current A 630, 1250 Max. Rated Current of Fuse: 63, 80, 100
7 Rated Short-Circuit Breaking Current kA - 31.5, 40, 50
8 Rated Active Load Breaking Current A 630, 1250 -
9 Rated No-Load Transformer Breaking Current - 63, 125 -
10 Rated Closed-Loop Breaking Current A 630, 1250 -
11 Rated Short-Time Withstand Current (4s) kA 25 -
12 Rated Peak Withstand Current kA 63 -
13 Rated Short-Circuit Making Current (Peak) kA 63 -
14 Rated Transfer Current A - 2000
15 Rated Cable Charging Current A 21
16 Rated Line Charging Current A 2.1
17 Rated Earth Fault Breaking Current A 100
18 Mechanical Life (Load Switch / Disconnector / Earthing Switch) times 10000 / 2000 / 2000
19 Rated Operating Voltage V ~220 / 110
20 Permissible Cumulative Wear of Moving & Fixed Contacts mm 3
21 Contact Gap mm 18±1
22 Over-Travel mm 4±1
23 Contact Bounce Time at Closing ms ≤5
24 Three-Phase Closing/Opening Asynchronism ms ≤2
25 Average Opening Speed m/s 1.5±0.3
26 Average Closing Speed m/s 0.8±0.2
27 Main Circuit Resistance (incl. Isolator) μΩ ≤200 ≤300 (excluding fuse)
28 Contact Pressure N 1600±200
29 Phase-to-Phase Center Distance mm 440±3 (High-Altitude Type: 500±3)

Note*: Relevant parameters are adjusted according to altitude.

Structure and Principle
Basic Structure

This three-phase load switch/combination unit consists of a frame, solid-insulated poles, a spring operating mechanism, isolation/earthing blades, sensors, and transmission parts. The isolating blades and vacuum interrupters are mounted on the frame. The earthing blades are at the bottom, and the operating mechanism (manual/electrical) is on the left side.

Working Principle

● Vacuum Switch: Uses a spring mechanism for closing and a solenoid/manual knob for opening. AC/DC power is supported. Status is visible through a window.

● Isolation/Earthing Blades: Mechanically interlocked; vacuum switch must be open first. Operated via handle with clear status indication.

● Fuse Trip: Uses striker-type fuses. Any phase fuse operation triggers a mechanical release to open the vacuum interrupter reliably (1–3J trip energy).

Outline and Installation Dimension
CJX2-D-4
Frequently Asked Questions (FAQ)
What is the rated voltage and frequency of this vacuum load switch?
The equipment operates at a rated voltage of 40.5 kV and a standard rated frequency of 50 Hz.
What are the ambient temperature limits for normal service conditions?
The unit is designed to operate normally within an ambient temperature range from a minimum of -40°C to a maximum of +65°C.
Can this apparatus be installed at high altitudes?
Yes, standard operation supports altitudes up to 4000 meters. A dedicated high-altitude configuration is available with a 500±3 mm phase-to-phase distance, and parameters are adjusted accordingly.
How does the fuse tripping mechanism protect the system?
It utilizes striker-type fuses. When any phase fuse operates, it activates a mechanical release with 1–3J of trip energy to immediately and reliably trip open the vacuum interrupter.
What is the mechanical lifespan of the load switch and earthing blades?
The mechanical life is rated at 10,000 operations for the vacuum load switch, 2,000 operations for the disconnector, and 2,000 operations for the earthing switch.
What type of interlocking system is integrated between switches?
The isolation and earthing blades are mechanically interlocked to guarantee safety, requiring the vacuum switch to be opened prior to operating either mechanism.

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