High-voltage isolator switch 3DN3

pantographIEC

Overview
Siemens Energy high-voltage disconnectors and earthing switches combine advanced technology and standardized quality across a wide voltage range. The product family is engineered for reliable isolation, safe maintenance operations and optimized life-cycle costs.

Production
Siemens Energy maintains consistent quality through optimized manufacturing, ongoing product development and certified quality management. A global production network reduces transport time and CO2 footprint and supports timely deliveries.

Main features

• Voltage range: 36 kV to 800 kV (page body)
• Rated current up to 5000 A
• Rated short-circuit current up to 80 kA (typically specified for 1 s; verify per application)
• Durable materials suitable for high seismic loads
• Designed for indoor and outdoor installation
• Switching capacity accounting for commutating currents and electromagnetic/electrostatic couplings

Advantages

• Maintenance-free contact options (depending on variant)
• Proven operational performance under harsh climatic conditions including coastal and ice-prone areas
• Type-tested to IEC 62271-102
• Quality management certified to DIN EN ISO 9001
• Routine-tested and pre-adjusted assemblies to simplify erection and commissioning
• Available lifetime technical support and service

Disconnectors and earthing switches variations
3DN1 — Center break disconnectors

• Most commonly used disconnector design worldwide
• Two rotating insulators open/close contacts by sideways motion
• Designs available on an integrated base frame
• Side opening increases phase clearance in parallel arrangements
• Flexible arrangement options: parallel, diagonal or in-line
• Integrated base frame adaptable to supporting structures
• Various color options available
• Sophisticated contact system for long service life and low maintenance
• Tested to national and international standards (IEC, ANSI, GOST R, GB)

3DN2 — Double side break disconnectors

• Used where phase space is limited or vertical opening is not feasible
• Three supporting insulators; center insulator rotates with the current path
• Outer insulators carry fixed contacts with two separation sections
• Compact, stable design for high mechanical tensile loads
• Compatible with surge arresters; optional self-interlocking mechanism

3DN3 — Pantograph disconnectors

• Require minimal mounting space and connect to busbar via characteristic scissors
• Vertical disconnection; diagonal or parallel arrangements possible
• Suitable for flexible and rigid busbar connections
• Compact, stable design allows high mechanical and thermal loads
• Self-interlocking prevents opening during short-circuit conditions

3DN4 — Vertical break disconnectors

• Current path opens vertically enabling minimal phase distances
• Performs a vertical swing plus rotation around its longitudinal axis
• Large distance between supporting and rotating insulators ensures dielectric strength in saline fog
• Delivered as finished assemblies to reduce installation and commissioning time

Modular design
All device types share common basic components and modular design:

• Current path
• Contact system* (except pantographs)
• Supporting insulator*
• Rotating insulator*
• Base frame
• Connecting rods** (except center break)
• Drive

Contact systems
Contact system concept provides:

• Increased contact force under short-circuit conditions
• High dynamic and thermal stability under leakage currents
• Optimized silver plating
• Maintenance-free, lubrication-free options with decades of field experience
• Designs largely based on the original RUHRTAL concept

Drive systems
Available drive systems and benefits:

• 3DV8 motor drive: integrated motor and gear unit with electrical equipment and auxiliary switch; motor-integrated transmission for low noise and maintenance-free operation
• 3DV4 manual drive: lockable hand lever for safe maintenance
• Drive assemblies delivered pre-adjusted to simplify installation and commissioning
• Stainless steel housings (IP54) and IEC-tested auxiliary switches
• Anti-condensation heater and compliance with international standards (IEC, GOST R, GB)

Applications

• Essential components in electrical substations (AIS and GIS)
• Provide visible gap isolation and ensure absolute de-energization for safe maintenance
• Used across power transmission, distribution, substations and infrastructure projects

Standards and testing

• Type-tested according to IEC 62271-102
• Tested to standards such as IEC, ANSI, GOST R and GB
• Quality control certified to DIN EN ISO 9001

Technical specifications

• Voltage range (page body): 36 kV to 800 kV
• Voltage range (extended/FAQ): up to 1200 kV (documented on the page)
• Rated current: up to 5000 A
• Rated short-circuit current: up to 80 kA (typically specified for 1 s — verify per application)
• Ambient temperature range: -60 … +55 °C
• Suitable for indoor and outdoor installation; designed for severe climates including coastal regions
• Materials and designs suitable for strong seismic activity
• Delivered as routine-tested, pre-adjusted assembly groups to reduce erection and commissioning time
• Maintenance-free bearings and contact systems (depending on variant)
• Options: self-interlocking, color choices, combinations with surge arresters