Product Overview

The ZN85 40.5KV 35KV Indoor Vacuum Circuit Breaker 630-2000A 20-31.5KA Embedded Pole Drawout/Fixed IEC Certificated for Switchgear VCB is JYDQ's purpose-built withdrawable handcart switching solution for KYN61-40.5 metal-clad switchgear panels. Manufactured in Zhejiang, China, this VCB carries ISO 9001, KEMA, IEC 62271-100, and GB 1984 certifications. It operates at 40.5kV, covers continuous current ratings of 1250A, 1600A, and 2000A, and delivers short-circuit interruption at 25kA and 31.5kA. Phase center spacing is 300mm, upper-lower terminal spacing is 400mm — both dimensionally matched to KYN61-40.5 cubicles for plug-in panel replacement without modification.

Commercial terms: FOB Ningbo/Shanghai pricing, MOQ of 1 set, delivery in 20–35 working days, T/T and L/C payment accepted, supply capacity 200 sets per month. Each unit ships in an export-standard plywood case with vacuum-sealed moisture barrier and shockproof bracing.

Vacuum Interruption Technology and Key Specifications

Each of the three independently sealed interrupter poles contains high-purity copper-chromium (CuCr) contacts inside a ceramic envelope evacuated below 10⁻⁴ Pa. When a fault occurs, the arc between separating contacts forms a diffuse metal-vapor plasma that collapses at current zero without producing ionized gas — giving a breaking time under 80 ms from trip-coil energization. The insulation medium for the interrupter poles is vacuum (sealed for life); external insulation uses air and solid dielectric via epoxy-encapsulated embedded poles, providing Class II pollution performance for indoor substation environments. The interrupter's dielectric recovery speed, typically exceeding tens of kV per microsecond, ensures reliable clearance of the full 31.5kA fault current even under demanding rate-of-rise-of-recovery-voltage (RRRV) conditions.

Selecting between the 25kA and 31.5kA configurations requires understanding a trade-off that most procurement teams underweight. Both variants look similar on a datasheet, but the design margins diverge significantly when cumulative fault duty is considered: the 25kA configuration achieves 230 full-rated breaking operations, while the 31.5kA configuration is rated for 30. If your application is standard feeder protection at moderate fault levels, the 25kA variant delivers more electrical endurance and is the appropriate choice. Generator circuits, bus-tie positions, and heavy industrial applications that genuinely operate at 31.5kA fault level require the higher-rated variant — the label alone does not confer extra reliability.

Key performance ratings: rated voltage 40.5kV, power-frequency withstand 95kV (1 min), lightning impulse withstand 185kV (peak). The operating sequence is O-0.3s-CO-180s-CO. Motor charging time is 15 seconds or less; coil voltages are DC 110V or DC 220V; motor supply is AC 220V or DC 220V. Mechanical endurance is 10,000 close-open cycles. Auxiliary contacts are 8NO + 8NC (extendable), with both mechanical and electrical anti-pumping protection and a non-resettable operation counter.

Application Scenarios

Feeder and transformer protection (40.5kV indoor substations): The ZN85 40.5KV 35KV Indoor Vacuum Circuit Breaker 630-2000A 20-31.5KA Embedded Pole Drawout/Fixed IEC Certificated for Switchgear VCB provides incoming and outgoing feeder protection with fault clearance under 80ms and automatic O-0.3s-CO-180s-CO reclosing. It also serves as the primary breaker for both step up step down transformer configurations in substations linking sub-transmission and distribution voltage levels, with continuous ratings to 2000A covering the largest 40.5kV transformer bank assignments. When specifying for transformer protection duty, confirm that the protection relay's inrush-restraint characteristic is configured correctly — the 8NO + 8NC auxiliary contact block supports standard relay wiring.

Bus-tie and capacitor bank switching: At 2000A / 31.5kA, this VCB handles bus-tie and bus-section duties in double-busbar installations. For reactive power compensation systems using rogowski coil-sensed digital relays, the breaker is type-test certified for single capacitor bank switching at 630A and back-to-back capacitor bank switching at 400A — restrike-free performance is ensured by the vacuum interrupter's rapid dielectric recovery.

Industrial applications: Steel mills, cement plants, mining facilities, and co-generation sites place unusually high switching demands on medium-voltage breakers. The ZN85-40.5 is suited to these environments because 10,000 mechanical operations and 230 full-rated breaking operations at 25kA provide a service life margin that absorbs the accumulated fault duty typical of heavy industrial operation. Both drawout and fixed installation variants are available.

Circuit Breaker Technical Parameters (40.5kV)

Why Choose the ZN85 40.5KV 35KV Indoor Vacuum Circuit Breaker 630-2000A 20-31.5KA Embedded Pole Drawout/Fixed IEC Certificated for Switchgear VCB

Zero-maintenance sealed interrupters: Unlike SF6 breakers requiring periodic gas monitoring, refilling, and end-of-life gas recovery, the vacuum interrupters in this VCB are sealed for life at 10⁻⁴ Pa — no field gas handling, no environmental reporting, no decommissioning expense. Contact integrity is factory-verified before shipment.

High electrical endurance: 230 full-rated breaking operations at 25kA results from optimized CuCr contact material, controlled contact stroke and velocity from the stored-energy spring mechanism, and inherently fast post-arc dielectric recovery. This endurance margin matters for long-lived substation assets where fault events accumulate over decades.

Confirmed KYN61-40.5 dimensional compatibility: Phase spacing (300mm), terminal spacing (400mm), racking mechanism geometry, shutter actuation dimensions, wheel gauge, and secondary plug positions all conform to KYN61-40.5 standards. This guarantees direct replacement of existing breaker handcarts without panel modification and maintains complete spares commonality across a mixed fleet.

Comprehensive KEMA type-test certification: Every ZN85-40.5 is type-tested to IEC 62271-100 and GB 1984 at KEMA-accredited laboratories, covering 95kV power-frequency and 185kV lightning-impulse dielectric testing, 31.5kA fault interruption, 2000A temperature rise, and 10,000-operation mechanical endurance. For international procurement projects where IEC type-test documentation is required for grid authority approval or tender qualification, JYDQ provides the complete factory test report package. Note that in markets where local grid codes differ from IEC requirements, project-specific compliance confirmation with the relevant grid authority should be obtained before finalizing the specification.

Applicable standards: IEC 62271-100, IEC 62271-1, IEC 62271-200, GB 1984, GB/T 11022, GB 3906.

FAQ

1. What is the advantage of vacuum arc extinction compared with air breaking?

Vacuum arc extinction has fast arc quenching speed, low arc energy, small contact ablation. It has stablebreaking performance and long service life, and does not produce harmful gas during operation.

2. What rated current options are available for vacuum circuit breakers?

Rated current optional range includes 630A, 1250A, 1600A, 2000A, 2500A, 3150A, 4000A. We can select the proper rated current according to your load current.

3. What anti-corrosion treatment can be done for vacuum circuit breakers?

For coastal salt fog environment we can use hot-dip galvanized metal structure and anti-corrosion paint coating. This treatment improves the resistance against salt spray and humidity corrosion.