Vacuum circuit breaker 3AP DT

SF6 gas-insulatedSF6 protectionSF6

Overview
Siemens Energy high-voltage circuit breakers cover a wide range of applications for transmission and substation grids. The product families (3AP, 3AV and variants) include live‑tank, dead‑tank, compact and disconnecting breaker types, and a Blue portfolio of SF6‑free technologies. Modular platforms allow adaptation to customer requirements while supporting long service intervals and compliance with environmental rules.

Types: comparison

• Live tank circuit breakers — 72.5 kV to 1100 kV: modular design; single‑ or three‑pole operation; porcelain or composite insulators; optional closing resistors.
• Dead tank circuit breakers — 72.5 kV to 550 kV: up to 90 kA interruption; 2‑cycle operation; common or separate bases; optional closing resistors; flexible current transformer solutions.
• Dead tank compact (DTC) — 145 kV and 245 kV: space‑saving arrangement with similar operational flexibility and reliability.
• Disconnecting circuit breakers (DCB) — 145 kV and 420 kV: integrated switching and disconnecting functions to reduce substation footprint and simplify design.

Live tanks and disconnecting circuit breakers (selected types and highlights)

• 3AP1 FG — up to 245 kV; one interrupter unit per pole; temperature range −60 to +55 °C.
• 3AP1 FI — up to 300 kV; single‑pole operation with separate bases; high seismic stability.
• 3AV1 FG Blue — vacuum technology, zero F‑gases, zero GWP; up to 145 kV; operational since 2017.
• 3AP2/3 FI — up to 550 kV; two interrupter units per pole; extended maintenance interval (~25 years noted).
• 3AP2 DCB 420 kV — breaker and disconnector in one device; cost‑ and space‑saving; single‑pole mechanism on separate bases.
• 3AP1 DCB 145 kV — breaker and disconnector in one device; three‑pole mechanism with common base; cost‑ and space‑saving.
• 3AP4/5 FI — up to 800 kV; four interrupter units per pole; available with or without closing resistors.

Dead tanks and dead tank compact (selected types and highlights)

• 3AP2/3 DT — up to 550 kV; two interrupter units per pole; extended maintenance interval (~25 years).
• 3AP1 DT — up to ~170 kV with mixed gases; suited to very low temperatures; available with or without closing resistors.
• 3AP1 DTC — compact arrangement for confined spaces and extreme conditions; two interrupter units per pole.
• 3AV1 Blue DT — SF6‑free dead‑tank variant marketed for low greenhouse impact; operates at 72.5–145 kV.

Blue portfolio
The Blue portfolio comprises SF6‑free products based on vacuum and clean‑air switching technologies. Blue solutions provide zero F‑gases and are intended as an alternative to SF6‑based switchgear where environmental impact is constrained.

Technical specifications and features

• Voltage capability: coverage from 72.5 kV up to 1100 kV depending on type.
• Interruption capability: dead‑tank designs rated up to 90 kA (product‑dependent).
• Environmental range: selected variants rated for extreme ambient temperatures (example: −60 to +55 °C).
• Design features: modular platforms; single‑ or multi‑pole configurations; porcelain or composite insulator options; optional closing resistors; DCB variants to reduce footprint.
• Maintenance: extended service intervals for specific designs (examples reference maintenance after ~25 years; some designs rated for ~6,000 operation cycles).

Circuit breaker technologies

• Vacuum interruption — used in the 3AV1 Blue portfolio: sealed‑for‑life vacuum interrupters, no F‑gas emissions, high switching performance and suitability for low temperatures.
• Self‑compression interrupter — arc‑quenching principle used in 3AP family up to 1100 kV with long development history.
• Stored‑energy spring‑drive mechanism — patented stored‑energy spring principle for reliable, low‑energy operating mechanisms in the 3AP family.

Accessories and digital solutions

• PSD control unit — controlled switching, auto‑reclose, IEC 61850 / DNP3 support, graphical evaluation and switching history.
• SiCEA01 contact erosion analyzer — evaluates contact wear from breaking currents; provides warnings/alarms; Ethernet communication supported.
• Sensgear® — digital monitoring for switchgear: real‑time monitoring, analytics, product‑specific data, encrypted cloud transmission for proactive maintenance and remote diagnostics.

Technical data (summary)

• Voltage ranges: typically 72.5 kV to 1100 kV across product families.
• Blue product voltages: SF6‑free vacuum / clean‑air products up to ~145 kV (examples: 3AV1 FG Blue, 3AV1 Blue DT).
• Interrupting capability: up to 90 kA for selected dead‑tank designs.
• Interrupter units per pole: 1 to 4 depending on voltage class and design.
• Temperature ratings: selected types rated for extreme low temperatures (example: −60 °C to +55 °C).