Isolator Breaker

The ZW20NG-7.2/400-12.5 isolator breaker is a core device independently developed by our company for outdoor power distribution applications. With a rated voltage of 7.2 kV, it is suitable for three-phase AC 50 Hz power systems. It adopts an advanced ZW20 three-phase common-box structural design, integrating the isolating switch within the three-phase poles. The isolation shaft is built into the mechanism box, while the isolation operating handle is externally accessible, resulting in a compact structure and significantly improved operational convenience.

● This isolator breaker supports both electric and manual operation modes, meeting operational requirements under various working conditions. It also features an innovative triple reliable locking mechanism, including mechanical interlocking, electrical interlocking, and an NKE electromagnetic lock, fundamentally eliminating the risk of misoperation and ensuring the safety of both equipment and personnel.

● With a protection rating of IP67, the isolator breaker can reliably operate in harsh outdoor environments, including high temperatures, high humidity, dust, and heavy rain. It has a mechanical life exceeding 10,000 operating cycles, demonstrating excellent long-term stability and providing continuous and reliable power protection for diverse power consumption scenarios.

● In terms of core performance parameters, the circuit breaker delivers outstanding performance. It has a rated current of 400 A, a rated short-time withstand current of 12.5 kA for 1 second, a rated short-circuit breaking current of no less than 30 operations, a rated short-circuit breaking current of 12.5 kA (RMS), and a rated short-circuit making current of 31.5 kA (peak). These parameters ensure rapid response and safe disconnection under short-circuit and fault conditions, effectively protecting the power system and downstream equipment.

Regarding insulation performance, the rated power-frequency withstand voltage (1 minute) is 22 kV between phases and to ground, 25 kV across vacuum interrupter contacts, and 35 kV across isolating switch contacts. The rated lightning impulse withstand voltage peak is 60 kV between phases and to ground, and 70 kV between contacts. The minimum external creepage distance is not less than 225 mm, and the ground clearance is 90 mm, ensuring reliable insulation performance under complex voltage conditions.

The operating mechanism adopts a spring-loaded design, with an operating force ranging from 100 N to 300 N. The return force of the charging handle is no less than 10 N, ensuring comfortable operation and rapid response. The disconnector switch uses a built-in direct-acting structure with a contact gap of 60 mm, and its operating force is also within the range of 100–300 N, ensuring convenient and efficient operation.

 

Thanks to its excellent overall performance, this product is widely used in outdoor substations, industrial park distribution systems, urban power grid renovation projects, rural power grid upgrades, and new energy power plant applications. It meets conventional power transmission and distribution requirements while also providing reliable power supply for special applications such as new energy integration. As an indispensable key device in outdoor power distribution systems, it provides a solid foundation for the safe, stable, and efficient operation of power networks.