72.5kV Three-phase AC Dead tank type SF6 circuit breaker-Rockwill

72.5kV Three-phase AC Dead tank type SF6 circuit breaker

Attributes Description Documentation Resource Library

Key attributes

Brand	ROCKWILL
Model NO.	72.5kV Three-phase AC Dead tank type SF6 circuit breaker
Rated voltage	72.5kV
Rated normal current	4000A
Rated frequency	50/60Hz
Rated short circuit breaking current	40kA
Series	RHD

Product descriptions from the supplier

Description

Description

72.5kV Three-phase AC Dead tank type SF6 circuit breaker is suitable for the rated voltage of 66kV, the rated frequency of 50Hz of the high-voltage transmission and transformation system, through the distribution and combined load current, interrupt the fault current, to achieve the control, measurement and protection of the transmission line, the product structure is compact, the area is small, especially suitable for earthquake-prone areas, polluted areas and areas with relatively small space size. The circuit breaker has excellent breaking performance, and the rated short-circuit breaking current can reach 31.5kA; The product is easy to install and maintain.

Main Features

Excellent breaking performance and long electrical life (＞20 operations).
Long mechanical life (10,000 cycles), reliable operation, frequent operability, low noise, simple structure, and long maintenance-free period.
Low center of gravity, suitable for seismic-prone areas.
Out-of-step breaking capability, usable as a tie circuit breaker.
Configurable built-in CTs per user requirements, with up to 15 current transformers for measurement or protection.

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：

electrical

Item	Unit	Parameters
Rated maximum voltage	kV	72.5
Rated maximum current	A	1600/2500/3150/4000
Rated frequency	Hz	50/60
1min Power frequency withstand voltage	kV	185
Lightning impulse withstand voltage	kV	450
First open pole factor		1.5/1.5/1.3
Rated short circuit breaking current	kA	25/31.5/40
Rated short - circuit duration	s	4/3
Rated out - of - phase breaking current		10
Rated cable charging current		10/50/125
Rated peak value withstand current	kA	80/100/125
Rated making current (peak)	kA	80/100/125
Creepage distance	mm/kV	25 - 31
SF6 gas leakage rate (per year)		≤1%
Rated SF6 gas pressure(20℃ gauge pressure)	Mpa	0.5
Alarm/blocking pressure(20℃ gauge pressure)	Mpa	0.45
SF6 annual gas leakage rate		≤0.5
Gas moisture content	Ppm(v)	≤150
Heater voltage		AC220/DC220
Voltage of control circuit	DC	DC110/DC220/DC230
Voltage of energy - store motor	V	DC 220/DC 110/AC 220/DC230
Applied standards		GB/T 1984/IEC 62271 - 100

mechanical

Name	unit	Parameters
Opening time	ms	27±3
Closing time	ms	90±9
Minute and conjunction time	ms	300
Together--ivide the time	ms	≤60
Simultaneity of opening	ms	≤3
Closing simultaneity	ms	≤5
Moving contact stroke	mm	150+2-4
Contact contact stroke	mm	27±4
Opening speed	m/s	4.5±0.5
Closing speed	m/s	2.5±0.4
Mechanical life	times	6000
Operation sequence		O - 0.3s - CO - 180s - CO
Note: The opening and closing speed and time are the characteristic values of the circuitbreaker when it is single divided and closed under rated conditions. The closing speed is theaverage speed of the moving contact from the rigid closing point to 10 ms before closing, andthe opening speed is the average speed of the moving contact within 10 ms from the justequinox to 10 ms after the separation.

Product use environment

Place of use: outdoor.
Ambient air temperature: -40℃~ +40℃
Altitude: no more than 1000m.
Air pollution level: Class IV.
Wind pressure: not more than 700Pa (equivalent to wind speed 34 m/s).
Earthquake level: no more than 9 degrees.
Relative humidity: the average daily relative humidity is not more than 95%; The average monthly relative humidity is not more than 90%.

Note: When the use conditions of the circuit breaker exceed the above provisions, it shall be determined by the user and the manufacturer through negotiation.

Documentation Resource Library

Restricted.

RHB Hybird Switchgear Catalog

Catalogue

English

Consulting

FAQ

Q: How to choose the voltage level of high-voltage sulfur hexafluoride circuit breaker?

1. Select the circuit breaker corresponding to the voltage level based on the power grid level
The standard voltage (12/24/40.5/72.5/126/170/245/363/420/550/800/1100kV) is matched with the corresponding nominal voltage of the power grid. For example, for a 35kV power grid, a 40.5kV circuit breaker is selected. According to standards such as GB/T 1984/IEC 62271-100, the rated voltage is ensured to be ≥ the maximum operating voltage of the power grid.
2. Applicable scenarios for non-standard customized voltage
Non standard customized voltage (11/22/44/52/132/230/275/300/345/400/380/765kV) is used for special power grids, such as the renovation of old power grids and specific industrial power scenarios. Due to the lack of suitable standard voltage, manufacturers need to customize according to power grid parameters, and after customization, insulation and arc extinguishing performance must be verified.
3. The consequences of selecting the wrong voltage level
Choosing a low voltage level can cause insulation breakdown, leading to SF leakage and equipment damage; Choosing a high voltage level significantly increases costs, increases operational difficulties, and may also result in performance mismatch issues.

Q: What are the core differences between live tank circuit breakers and tank circuit breakers?

The core differences between porcelain column circuit breakers and tank circuit breakers—two main structural types of high-voltage circuit breakers—lie in six key aspects.
Structurally, porcelain column types are supported by porcelain insulation pillars, with open-layout components like arc extinguishing chambers and operating mechanisms. Tank types use metal-sealed tanks to encapsulate and highly integrate all core parts.
For insulation, the former relies on porcelain pillars, air, or composite insulating materials; the latter combines SF₆ gas (or other insulating gases) with metal tanks.
Arc extinguishing chambers are mounted on the top or pillars of porcelain columns for the former, while built inside metal tanks for the latter.
In application, porcelain column types suit outdoor high-voltage distribution with a dispersed layout; tank types adapt flexibly to indoor/outdoor scenarios, especially space-constrained environments.
Maintenance-wise, the former’s exposed components enable targeted repairs; the latter’s sealed structure reduces overall maintenance frequency but requires full inspections for local faults.
Technically, porcelain column types offer intuitive structure and strong anti-pollution flashover performance, while tank types boast excellent sealing, high SF₆ insulation strength, and superior resistance to external interference.

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