Customizable LW Series 66KV/72.5KV Outdoor High-Voltage Side-Mounted SF6 Circuit Breaker — Product Overview

The Customizable LW Series 66KV/72.5KV Outdoor High-Voltage Side-Mounted SF6 Circuit Breaker, manufactured by JYDQ in Zhejiang, China, is a premium transmission-level switching device for protection and control of 66kV and 72.5kV outdoor air-insulated substations. The LW Series adopts a live-tank porcelain-insulated interrupter design with a side-mounted motor-driven stored-energy spring operating mechanism — a configuration proven in utility-grade 72.5kV substation applications worldwide. Model coverage includes LW-72.5 and LW-66 Series variants. Certifications: ISO 9001, full type-test to IEC 62271-100 and GB 1984 by KEMA-accredited independent high-power laboratories. Rated voltage: 72.5kV / 66kV. Rated current: 2500A / 3150A. Rated short-circuit breaking current: 31.5kA / 40kA. Place of origin: Zhejiang, China. Supply ability: 100 sets per month, with delivery in 30 to 45 working days after deposit receipt.

Core Technical Specifications

Key Technical Features

High-Speed Auto-Puffer Arc Extinction

The Customizable LW Series 66KV/72.5KV Outdoor High-Voltage Side-Mounted SF6 Circuit Breaker uses a high-performance auto-puffer arc extinguishing system for 72.5kV-class fault interruption. The operating mechanism transfers mechanical energy to a piston assembly during the opening stroke, compressing SF6 gas into a high-velocity blast across the separating arcing contacts. Rated short-circuit breaking capacities of 31.5kA and 40kA are achieved with a peak making current of 80kA and arcing time of no more than 0.03 seconds. Total fault clearance from trip coil energization is under 60 milliseconds. This speed limits arc energy release, reduces thermal stress on connected transformers, and shortens the recovery voltage exposure window during close-in fault events. The first open pole coefficient of 1.5 ensures correct interruption of the most severely stressed phase under three-phase unearthed fault conditions without risk of restrike. Near-zone fault interruption has been type-tested at 75% and 90% of rated breaking current, and out-of-step breaking at 25% of rated current confirms suitability for system separation duties.

Side-Mounted Spring Operating Mechanism

A motor-driven stored-energy spring mechanism stores closing energy via a 900W motor rated AC/DC 220V. Full spring charge is achieved within 15 seconds, supporting the standard O-0.3s-CO-180s-CO auto-reclose sequence. The side-mounted layout places all control, monitoring, and manual operating interfaces at ground-accessible height, eliminating the need for elevated work platforms during routine preventive maintenance and post-fault diagnostic inspections. The mechanism includes 8NO and 8NC auxiliary contacts, a non-resettable mechanical operation counter, position indicators, and mechanical plus electrical anti-pumping interlocks. Mechanical life is rated at 3,000 close-open operations. From field experience, the value of ground-level maintenance access is most apparent during scheduled outage windows of limited duration — situations where personnel safety procedures and access logistics can consume more time than the maintenance task itself. An integrated hand-crank provision allows manual emergency spring charging without reliance on the motor supply.

Transmission-Class Dielectric Integrity and Certification

Each interrupter is engineered to withstand a 1-minute power-frequency test voltage of 140kV and lightning impulse test voltage of 325kV. Weather-grade glazed porcelain insulators provide standard creepage of 1,813mm and heavy-pollution creepage of 2,248mm for Class IV environments. When evaluating suppliers for transmission substation procurement, comparing rated specifications alone is insufficient — what matters most is whether the type test documentation from an accredited laboratory covers all IEC 62271-100 test duties at the rated breaking current, including near-zone fault interruption at 75% of rated current and out-of-step breaking at 25% of rated current. JYDQ's KEMA-accredited type test documentation covers all required test duties, providing the technical basis for utility pre-qualification submissions and grid authority connection approval packages. IEC 62271-100 compliance should be treated as the foundation, not the ceiling — buyers specifying for markets with national grid codes should confirm the required insulation level and creepage grade with application engineering before order placement.

Application Scenarios

Transmission Substation Feeder and Transformer Protection

The LW Series is purpose-engineered for incoming and outgoing feeder positions in 66kV and 72.5kV outdoor air-insulated substations, providing high-speed fault clearance and auto-reclose functionality for overhead transmission lines. With a continuous current of 3150A and 40kA breaking capacity, it also protects primary-side 72.5kV power transformers against through-fault currents, inrush transients, and lightning-induced overvoltages. The 3150A/40kA configuration serves bus-tie and bus-section duties in double-busbar substations, enabling reliable load transfer and fault isolation during maintenance and contingency switching operations.

Industrial and Heavy-Duty Applications

The breaker delivers reliable performance in steel plants, smelters, chemical complexes, and co-generation facilities where high continuous load currents, frequent switching, and elevated fault levels demand uncompromising reliability. The IP55 weatherproof control cabinet and hot-dip galvanized steel support frame protect against corrosive, high-humidity, and dust-laden industrial atmospheres. The complete three-pole assembly weighs approximately 1,000 kg, enabling cost-effective transport and straightforward cranage for brownfield substation installations. JYDQ provides export-standard heavy-duty wooden crate packaging with VCI anti-corrosion wrap and humidity indicator for reliable delivery to international project sites.

Commercial Terms

FAQ

1. What are the core advantages of SF6 circuit breaker compared with vacuum circuit breaker?

SF6 circuit breaker has stronger insulation and arc extinguishing capability, more stable performance under high voltage and large short-circuit current. It is the preferred solution for high voltage and extra-high voltage power transmission and distribution systems.

2. What key technical parameters can be customized for SF6 circuit breaker?

We can customize rated current, rated short-circuit breaking current and gas pressure setting according to your local power grid short-circuit capacity and load condition.

3. Can SF6 circuit breaker operate in high altitude areas?

Yes. If the installation altitude exceeds 1000m, we will optimize the external insulation design and increase creepage distance to prevent flashover under low air density.

4. What certifications do your SF6 circuit breakers have?

All our SF6 circuit breakers are CE certified. Relevant CE test documents can be supplied for project bidding and site acceptance.

5. What technical support can we get during the warranty period?

Within the 10-year warranty period, our engineers offer remote guidance for equipment commissioning and routine operation check.