Three-phase AC Dead tank type SF6 circuit breaker source manufacturer 72.5kV
Key attributes
| Brand | ROCKWILL |
| Series | RHD |
| Rated maximum voltage | 72.5kV |
| Rated maximum current | 2000~3150 A |
| Lightning impulse withstand voltage | 325/375 |
| Rated short-circuit breaking current | 31.5~50 kA |
| Rated frequency | 50/60 Hz |
Description
This 72.5kV three-phase AC dead tank SF₆ circuit breaker is designed for 66kV high-voltage transmission and transformation systems at 50Hz rated frequency. It distributes and combines load currents, interrupts fault currents, and provides control, measurement, and protection of transmission lines.
The product features a compact structure with a small footprint, making it particularly suitable for earthquake-prone areas, heavily polluted regions, and space-constrained substations. Excellent breaking performance with rated short-circuit breaking current up to 63kA simplifies installation and maintenance.
The breaker is also configurable as a module within an HGIS (hybrid gas-insulated combined apparatus) system, using standard interface dimensions compatible with GCB, TPS isolation-grounding switches, PTs, and other modules for flexible substation layout.
Core Features
- High Breaking Capacity & Long Electrical Life：Excellent breaking performance with rated short-circuit breaking current up to 63kA. Electrical endurance >20 full-capacity short-circuit operations (E2 class).
- Adopt pointer-type density relays for pressure and density monitoring
- Seismic-Ready Dead Tank Design：Low center of gravity inherent to the dead tank design makes the breaker ideally suited for seismic-prone areas, outperforming porcelain column (live tank) alternatives in earthquake resistance.
- Out-of-Step Breaking Capability：Capable of breaking under out-of-step (asynchronous) conditions, enabling use as a tie circuit breaker between interconnected grid sections.
- Flexible Built-In CT Configuration：Configurable built-in current transformers per user requirements, supporting up to 15 CT cores for measurement or protection. Eliminates external CT space and insulation concerns.
System Architecture
The gas-insulated metal composite combined electrical appliance (HGIS) is composed of several standard functional modules, such as circuit breaker GCB (single and double busbars), isolation-grounding switch TPS, voltage transformer PT, current transformer CT, etc. These modules have the same interface form and size. Various modules can be combined to meet the design and layout requirements of various substations.
Single-busbar single-isolation scheme
Single-busbar double -isolation scheme
Main characteristics
| Rated maximum voltage | kV | 72.5 |
| Rated maximum current | A | 2000~3150 |
| Rated frequency | Hz | 50/60 |
| Lightning impulse withstand voltage | kV | 325/375 |
| Rated short-circuit breaking current | kA | 31.5~50 |
| Rated peak withstand current | kA | 100~125 |
| Creepage distance | mm/kV | 25~31 |
| Partial discharge | pC | ≤10 |
| Opening time | ms | ≤30 |
| Alarm/blocking pressure | MPa | 0.45/0.40 |
| Gas moisture content | ppm(v) | ≤150 |
| Heater voltage | V | AC220 |
| Voltage of energy-store motor | V | DC110/220 |
| 1min Power frequency withstand voltage | kV | 140/160 |
| First open pole factor | — | 1.5 |
| Rated short-circuit duration | s | 4 |
| Rated cable/line charging breaking current | A | 160~200 |
| Rated making current (peak) | kA | 100~125 |
| Operation sequence | — | O-0.3s-CO-180s-CO |
| Breaking time | ms | ≤60 |
| Closing time | ms | ≤100 |
| Rated SF₆ gas pressure | MPa | 0.5~0.6 |
| SF₆ annual gas leakage rate | % | ≤0.5 |
| Mechanical life | times | 10000 |
| Voltage of control circuit | V | DC110/220 |
| Applied standards | — | GB/T 1984 / IEC 62271-100 |
Service environment
- Ambient temperature: -40℃ ~ +55℃Humidity:
- Daily average humidity ≤ 95%, monthly average ≤ 90%
- Wind pressure: less than 700 Pa
- Above sea level: Maximum installation altitude: 3000m.
- Earthquake intensity: not more than 9 degrees.
- Air Contamination: III grade.
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If it needs to be installed in plateau areas with an altitude higher than 1,000 meters, it is essential to consult with the manufacturer to take necessary measures to strengthen insulation during the ordering process.
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When operating in an area with a temperature of -40℃, measures need to be taken to prevent SF6 gas from liquefying.
Reference Projects for Dead Tank Circuit Breaker
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Case Study of Rockwill 72.5kV Dead Tank Circuit Breaker Project in South AfricaFacing the stringent operational challenges of South Africa’s high-load industrial power grid, the 72.5kV fully enclosed dead-tank circuit breaker delivers robust performance to withstand intense solar radiation, dust and high temperatures. With superior insulation and high short-circuit breaking capacity, it builds a long-term high-voltage safety barrier for mining areas and main power grids.01 Project Overview1.1 Project BackgroundSouth Africa, as the most industrialized country in Afric
Documentation Resource Library Dead Tank Circuit Breaker
FAQ for Dead Tank Circuit Breaker
Live tank breakers are well-suited for outdoor high-voltage distribution with a dispersed layout. Dead tank breakers flexibly adapt to both indoor and outdoor applications, especially in space-constrained substations or where compact installation is required.
In a live tank breaker, the arc chamber is mounted at the top or side of the column, exposed to ambient air. In a dead tank breaker, the arc chamber is placed inside the metal tank, fully sealed.
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