The ZN85-40.5 Indoor High Voltage Vacuum Circuit Breaker features an innovative composite insulation structure that combines the best attributes of solid and gas insulation technologies. This design achieves exceptional dielectric performance while enabling a remarkably compact footprint, making it ideal for space-constrained 40.5kV indoor applications where traditional air-insulated designs would require significantly larger clearances.
The three-phase vacuum interrupters and associated live parts are each housed within independent epoxy resin insulation cylinders, forming a complete composite insulation system. This cylinder design provides robust isolation between phases and from ground, meeting all air gap and creepage distance requirements under normal operating conditions. The epoxy material's high dielectric strength and tracking resistance ensure consistent performance even in environments with moderate humidity or contamination.
The composite structure enables an exceptionally compact phase-to-phase spacing of only 300mm. This is a significant reduction compared to traditional designs, achieved by encapsulating the vacuum interrupters and their connections within the insulating cylinders. The main conductive circuit components—including the moving and stationary contacts—are fully enclosed, eliminating the need for large air gaps while maintaining full lightning impulse withstand voltage of 185kV and power frequency withstand voltage of 95kV.
The insulation cylinders also contribute to enhanced reliability by protecting the vacuum interrupters and connections from environmental contaminants such as dust, moisture, and conductive particles. This sealed construction prevents the accumulation of pollution on critical insulation surfaces, which can lead to tracking and flashover in traditional open designs. The cylinders are mounted directly on the breaker frame, ensuring precise alignment and consistent mechanical support.
Furthermore, the composite insulation system simplifies maintenance. Unlike open air-insulated designs that require periodic cleaning of live parts, the ZN85-40.5's sealed cylinders protect internal components from contamination, reducing maintenance frequency and labor costs. The insulation integrity can be verified through standard power frequency withstand testing without disassembly.
Therefore, the ZN85-40.5's composite insulation structure delivers the dielectric performance required for 40.5kV applications in a compact, reliable, and low-maintenance package. Putai also supports customization and the supply of related medium-voltage accessories to meet system integration needs. For technical consultation on insulation design and dielectric coordination, contact our engineering specialists.
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