Presentation · EN — 28-slide Siemens Energy Grid Technologies product presentation (16:9, 2025, 'Unrestricted') on the 8DQ1 gas-insulated switchgear up to 420 kV, 63 kA, 5000 A / 6300 A. The deck positions the 8DQ1 at the top of the Siemens Energy GIS portfolio (alongside the vacuum/clean-air 8VM1, 8VM3 and 8VN1 and the SF6 8DN8 and 8DN9), gives the full technical data table for the 245 kV and 420 kV ratings, and reports an installed base of more than 3,500 8DQ1 installations worldwide. The bulk of the presentation is a module-by-module walk-through of the design: the modular building-block system (circuit breaker, busbar, disconnector/earthing switch, instrument transformers, RC-divider, surge arrester, cable/outdoor/transformer termination modules), the self-compression interrupter unit and its stored-energy spring mechanism, the passive busbar concept, and the bay configurations — cable feeder (3.8 m height x 5.8 m depth at 2.2 m bay width), overhead-line feeder, bus coupler and 1 1/2 circuit-breaker arrangement — closing with the list of fulfilled IEC 62271 standards.
The portfolio slide (slide 2) places the 8DQ1 at the top of the Siemens Energy GIS range. The 8VM1, 8VM3 and 8VN1 use vacuum interrupter technology with clean-air insulation; the 8DN8, 8DN9 and 8DQ1 use the self-compression interrupter principle with SF6 insulation. Ratings as printed on the slide:
| Product line | Rated voltage (up to) | Rated short circuit-breaking current (up to) | Rated current busbar (up to) | Rated current feeder (up to) |
|---|---|---|---|---|
| 8VM1 | 72.5 kV | 25 kA | - | 1250 A |
| 8VM3 | 72.5 kV | 31.5 kA | - | 1250 A |
| 8VN1 | 145 kV | 50 kA | 3150 A | 3150 A |
| 8DN8 | 145 kV | 40 kA | 3150 A | 3150 A |
| 8DN8 | 170 kV | 63 kA | 4000 A | 4000 A |
| 8DN9 | 245 kV | 50 kA | 4000 A | 4000 A |
| 8DQ1 | 420 kV (245 kV) | 63 kA (80 kA) | 6300 A | 5000 A |
| 8DQ1 | 420 kV | 80 kA | 6300 A | 5000 A |
| 8DQ1 | 550 kV | 63 kA | 5000 A | 5000 A |
The technical data table (slide 3) gives the full ratings for both voltage classes side by side. The slide closes with 'Other values on request'. Values as printed:
| Parameter | 245 kV | 420 kV |
|---|---|---|
| Rated frequency | 60 Hz | 50/60 Hz |
| Rated short-duration power-frequency withstand voltage (1 min), up to | 460 kV | 650 kV |
| Rated lightning impulse withstand voltage (1.2 / 50 µs), up to | 1050 kV | 1425 kV |
| Rated switching impulse withstand voltage (250 / 2500 µs), up to | - | 1050 kV |
| Rated continuous current — busbar, up to | 6300 A | 6300 A |
| Rated continuous current — feeder/bus coupler, up to | 5000 A | 5000 A |
| Rated short-circuit breaking current (< 2 cycles), up to | 80 kA | 63 kA |
| Rated peak withstand current, up to | 216 kA | 170 kA |
| Rated short-time withstand current (up to 3 s), up to | 80 kA | 63 kA |
| Leakage rate p.a. and gas compartment (type-tested) | < 0.1% | < 0.1% |
| Driving mechanism of circuit-breaker | stored-energy spring | stored-energy spring |
| Rated operating sequence | O-0.3 s-CO-3 min-CO; CO-15 s-CO | O-0.3 s-CO-3 min-CO; CO-15 s-CO |
| Interrupter technology | self-compression principle | self-compression principle |
| Insulation medium | SF6 | SF6 |
| Bay width | 2200 mm | 2200 mm |
| Bay height, depth (depending on bay arrangement) | 3800 mm x 5800 mm | 3800 mm x 5800 mm |
| Bay weight (depending on bay arrangement) | 11 t | 11 t |
| Ambient temperature range | -30 °C up to +55 °C | -30 °C up to +55 °C |
| Installation | indoor / outdoor | indoor / outdoor |
| First major inspection | > 25 years | > 25 years |
| Expected lifetime | > 50 years | > 50 years |
| Standards | IEEE | IEC/IEEE/GOST |
The references slide (slide 4) reports more than 3,500 8DQ1 installations worldwide, broken down by region on a world map: 400+ installations in America, 770+ in Europe (incl. Russia), 430+ in Africa, 1,900+ in Asia and 5+ in Australia. No individual customers or projects are named on the slide.
The 8DQ1 is built from a kit of standardized modules (slide 5): circuit breaker, busbar, disconnector / earthing switch, current transformer, voltage transformer, RC-divider, surge arrester, cable module, outdoor bushing and transformer module. Each module is shown as a sectional drawing in the deck, and the modules combine into the bay configurations shown later in the presentation.
The switchgear bay slide (slide 6) pairs a labeled cutaway with the matching single-line diagram, distinguishing gas-tight from gas-permeable bushings. Thirteen components are identified: (1) circuit-breaker control unit with spring operating mechanism; (2) busbar I; (3) busbar disconnector I; (4) busbar disconnector II; (5) busbar II; (6) earthing switch; (7) circuit-breaker; (8) current transformer; (9) earthing switch; (10) outgoing disconnector; (11) high-speed earthing switch; (12) voltage transformer; (13) cable sealing end.
The circuit breaker module slide (slide 7) shows a colored sectional rendering with twelve numbered parts — (1) shielding and current conductor, (2) housing, (3) rated current contact, (4) arc contact, (5) piston with valve plate, (6) moving contact, (7) insulator, (8) operating rod, (9) moveable pin, (10) nozzle, (11) head cylinder, (12) valve group — alongside product photos of the assembled breaker module.
The self-compression interrupter unit (slide 8) is explained across four switching states: breaker in 'on' position, opening with main contact open, opening with arcing contact open, and breaker in 'off' position. Labeled elements include the moving arcing contact, main contact, check valves, compression volume, steering gear, moving arcing rod, insulating nozzle, auxiliary nozzle, contact cylinder and heating volume.
The circuit-breaker is driven by a spring operated (stored-energy spring) mechanism, shown on slide 9 in the 'off' position with the closing spring loaded (the slide's seventeen part labels are numeric callouts on the drawing; the deck text does not name them individually).
The disconnector module (slide 10) is motor-driven via a coupling rod, with a mechanical position indicator and an optional viewport for visual verification of the contact position.
Earthing is covered by an earthing switch and a high-speed earthing switch (slide 11), likewise with motor drive, coupling rod, position indicator and optional viewport.
The shared operating mechanism of disconnector and earthing switch (slide 12) is shown with its rocker and auxiliary switch.
The 8DQ1 busbar (slide 13) is a passive module — conductor, connecting-ball type assembly and expansion joint — with no active switching devices, which the deck calls the most probable reason for failures. Advantages listed verbatim: busbar failure more than unlikely; no decomposition of SF6 gas; no shutdown during extension or maintenance works.
Current transformers use external cores with a secondary terminal housing (slide 14); an inductive voltage transformer module is shown on slide 15.
As a non-conventional alternative, the RC-divider (slide 16) is a low-power instrument transformer (signal power output <= 2.5 W) with high accuracy over a wide frequency range (DC up to 2.5 kHz AC) and ferro-resonance-free technology with no saturation. It shares a common gas compartment with the switchgear — no gas-tight bushing required (a separate gas compartment is possible) — and does not need to be disassembled for on-site GIS high-voltage tests, so no disconnector is required. It is type-tested according to IEC, IEEE, GOST and GB (China), reduces size and weight, and is delivered with a pre-assembled PVC cable (length to be defined) to the secondary connection box. Typical applications: power quality monitoring at the interface between utility and industrial plant, and protection and control.
Three termination options connect the GIS to the network: the cable termination module (slide 17) with sliding contact and conductor; the outdoor termination module (slide 18) consisting of angle module, adapter housing and outdoor bushing; and the transformer termination module (slide 19) with extension module, expansion joint and corner ball-type assembly, whose section labels conductor, shield and intermediate plate.
The integrated surge arrester (slide 20) houses metal-oxide resistors on a supporting tube with grading hood and spring contact inside its own housing, connected via an SF6 bushing. It carries an access cover with rupture disk assembly, gas pressure/density monitoring, and a grounding connector that also serves as connection point for arrester condition monitoring, e.g. a surge counter.
The deck closes the design walk-through with the standard bay configurations, each shown as sectional drawing plus single-line diagram: cable feeder (slides 21-22), overhead-line feeder (slide 23) and bus coupler (slide 24). The cable feeder dimensions are 3.8 m height and 5.8 m depth at 2.2 m bay width (slide 22).
A 1 1/2 circuit-breaker arrangement (slide 25) is shown as a double-busbar layout (Busbar I / Busbar II, breaker bays C01.A / C01.B / C01.C) with 5100 mm height and 21500 mm overall diameter length.
The 8DQ1 fulfills the requirements of the latest IEC standards (slide 26):
| Standard | Title |
|---|---|
| IEC 62271-1 | High-voltage switchgear and controlgear — Part 1: Common specifications |
| IEC 62271-100 | High-voltage switchgear and controlgear — Part 100: Alternating current circuit-breakers |
| IEC 62271-102 | High-voltage switchgear and controlgear — Part 102: Alternating current disconnectors and earthing switches |
| IEC 62271-110 | High-voltage switchgear and controlgear — Part 110: Inductive load switching |
| IEC 62271-203 | High-voltage switchgear and controlgear — Part 203: Gas-insulated metal-enclosed switchgear for rated voltages above 52 kV |
| IEC 62271-207 | High-voltage switchgear and controlgear — Part 207: Seismic qualification for gas-insulated switchgear assemblies for rated voltages above 52 kV |
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