8DQ1
Gas-insulated switchgear 8DQ1, 245–550 kV, up to 80 kA, SF6 self-compression interrupters, stored-energy spring drive
8DQ1
- Part of the Siemens Energy 8D GIS series introduced in 1968 — more than 24,000 bays installed worldwide with well over 285,000 years of recorded bay operation.
- Covers transmission voltage classes 245 kV, 420 kV and 550 kV, with short-circuit breaking currents up to 80 kA (245 kV and 420 kV high-rating classes) and rated busbar currents up to 6300 A.
- Self-compression SF6 interrupter units; stored-energy spring operating mechanism based on the drive concept of the 3AP circuit-breaker family, with maintenance-free charging mechanism.
- Type-tested gas leakage rate below 0.1 % per year and gas compartment; first major inspection after more than 25 years, expected lifetime over 50 years.
- Suitable for indoor and outdoor installation; ambient temperature −30 °C to +55 °C (245 kV and 420 kV 63 kA bays) or −25 °C to +55 °C (420 kV 80 kA and 550 kV bays).
Transmission substationsExtra-high-voltage networks up to 550 kVHigh short-circuit-level grid nodes (up to 80 kA)Indoor and outdoor switchgear installations
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8DQ1 covers up to 550 kV of the gas-insulated switchgear range (≤ 550 kV across the category, √ scale).
Specifications
Main
| Product family | 8DQ1 (Siemens Energy 8D series GIS) |
| Type | Gas-insulated, metal-enclosed switchgear (GIS) |
| Voltage classes | 245 kV / 420 kV / 550 kV |
| Insulation medium | SF6 |
| Interrupter technology | Self-compression principle |
| Installation | Indoor / outdoor |
| Application | Transmission substations |
Electrical
| Rated voltage | Up to 245 / 420 / 550 kV (rating-class dependent) |
| Rated frequency | 245 kV class: 60 Hz; 420 / 550 kV classes: 50/60 Hz |
| Rated short-duration power-frequency withstand voltage (1 min) | Up to 460 kV (245 kV) / 650 kV (420 kV) / 740 kV (550 kV) |
| Rated lightning impulse withstand voltage (1.2/50 µs) | Up to 1050 kV (245 kV) / 1425 kV (420 kV) / 1550 kV (550 kV) |
| Rated switching impulse withstand voltage (250/2500 µs) | Up to 1050 kV (420 kV) / 1175 kV (550 kV); not specified for 245 kV class |
| Rated normal current, busbar / feeder | Up to 6300 A / up to 5000 A (all classes) |
| Rated short-circuit breaking current (< 2 cycles) | Up to 80 kA (245 kV, 420 kV high-rating class) / up to 63 kA (420 kV, 550 kV) |
| Rated peak withstand current | Up to 216 kA (80 kA classes) / up to 170 kA (63 kA classes) |
| Rated short-time withstand current (up to 3 s) | Up to 80 kA (80 kA classes) / up to 63 kA (63 kA classes) |
Mechanical / environment
| Circuit-breaker drive mechanism | Stored-energy spring |
| Rated operating sequence | O-0.3 s-CO-3 min-CO | CO-15 s-CO |
| Bay width | 2200 mm (245 kV, 420 kV 63 kA) or 3600 mm (420 kV 80 kA, 550 kV) |
| Bay height × depth (depending on bay arrangement) | 3800 × 5800 mm (2200 mm bays) or 4800 × 10000 mm (3600 mm bays) |
| Bay weight | 11 t (2200 mm bays) or 21 t (3600 mm bays) |
| Ambient temperature range | −30 °C to +55 °C (2200 mm bays) / −25 °C to +55 °C (3600 mm bays) |
| Gas leakage rate (type-tested) | < 0.1 % per year and gas compartment |
| First major inspection / expected lifetime | > 25 years / > 50 years |
Standards & certifications
| Standards per rating (datasheet) | 245 kV class: IEEE; 420/550 kV classes: IEC / IEEE / GOST |
| Type and routine testing | Circuit breakers type-tested in accordance with latest IEC and ANSI standards; Berlin lead-factory testing laboratory accredited to IEC 17025, PEHLA network, member lab of the Short-Circuit Testing Liaison (STL) |
Options & variants
Rating classes as published in the 8DQ1 technical datasheet (2025); other values on request. Rows reflect the manufacturer's configuration matrix, not order data (the upstream catalog build reported no SAP E3501 order lines for this family since 2015; that SAP claim was not re-verified in this review).
| Rated voltage | Breaking current | Busbar / feeder current | Frequency | Standards |
|---|---|---|---|---|
| 245 kV | up to 80 kA | 6300 A / 5000 A | 60 Hz | IEEE |
| 420 kV | up to 63 kA | 6300 A / 5000 A | 50/60 Hz | IEC / IEEE / GOST |
| 420 kV | up to 80 kA | 6300 A / 5000 A | 50/60 Hz | IEC / IEEE / GOST |
| 550 kV | up to 63 kA | 6300 A / 5000 A | 50/60 Hz | IEC / IEEE / GOST |
Documents & downloads
Datasheet Gas-insulated switchgear type 8DQ1 — Technical data (2025)
Catalog Gas-insulated switchgear from 72.5 kV up to 550 kV — family catalog, 2022 (current online edition)
Datasheet 8DQ1 technical datasheet 2021 (Chinese)
Ordered designations
Representative orderable type designations of this family — searchable via the catalog search.
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