VZF(R)-12 Removable Vacuum Load Break-Fuse Unit for 1000mm Switchgear

Structural Features of VZF(R)-12 vacuum switch

Key Technical Features
Drawer-Type Compatibility: Revolutionizes secondary distribution by enabling integration with withdrawable circuit breakers and ring main units (RMUs).

Dual Protection Technology: Simultaneously employs fuses + relay protection (25kA breaking capacity) to prevent fault escalation.

Safety Interlocks: Comprehensive mechanical/electrical anti-misoperation systems with pre-energization function.

Fuse Monitoring: Dual mechanical/electrical indication for real-time fault alerts.

Transformer Protection: Superior station/service transformer protection versus traditional fuse trolleys.

Applications
Ideal for:

Transformer protection in substations

Secondary distribution networks

Ring Main Units (RMUs)

Mining/industrial power systems

Technical Parameters of VZF(R)-12 vacuum switch

Mechanical Characteristic Parameters

Technical Parameters

Dimensions（Suitable for 1000mm width metal-enclosed switchgear）

Transformer Capacity and Fuse Selection

Since fuses can interrupt large short-circuit currents in less than 10 ms — with a breaking capacity up to 50 kA — they provide highly effective protection for transformers.

When coordinating transformers with fuses (see Table 1), it is essential to consider the inrush current that the fuse may be exposed to. Therefore, the rated current of the fuse should be at least 1.6 times the transformer’s rated current. Designers must also take into account potential fluctuations in power system parameters and provide a reasonable safety margin when selecting fuses.

When using fuses to protect high-voltage motors, the starting frequency of the motor must also be considered. In cases of frequent starting, the fuse may not have adequate time to cool down between operations, potentially affecting its performance.

Table 1: Fuse Selection for Transformer Protection