Circuit-Breaker
General Information
- Description
- Locations Production / Cooperation
- Technology
- Installation and Commissioning
Siemens high-voltage circuit-breakers offer the optimum technical and economical solution for every requirement. Depending on the application and the voltage level, they are equipped with the following combinations of arc quenching principle and operating mechanism:
- Self-compression principle with stored energy spring mechanism
- Puffertype with hydraulic mechanism
All the live- and dead-tank circuit-breakers, as well as the gas-insulated switchgear (GIS), are equipped with the same components. Longevity, reliability and highest availability in all climate zones in the world distinguish Siemens high-voltage circuit-breakers from all others.
Germany, Berlin
Siemens AG Schaltwerk Hochspannung,
E T HP CB
Nonnendammallee 104 - 107 13629 Berlin
Phone: +49 30 386 26040
Fax: +49 30 386 25867
China, Hangzhou
Siemens High-Voltage Circuit-Breaker Co. Ltd. 6th Road of Xisha District Hangzhou 310018 PR China
Phone: + 86 571 6910 380
Fax: + 86 571 6910 380
USA, Jackson
Siemens AG
444 Highway 49 South
Richland, Mississippi, USA
Phone: + 1 601 939 0550
Fax: + 1 601 939 3606
Technology
Optimum solutions for every need. Circuit-breakers lie at the heart of any switchgear installation. However, as well as being extremely safe and reliable they must also be able to ensure sustained economy and long service life. Consequently, the demands made upon circuit-breakers are stringent: Dielectric strength Reliable making and breaking of the conducting path Constant arc-quenching capacity during short-circuits - throughout their whole service life Powerful, maintenance-free operating mechanisms.
Optimum solutions for every need
Circuit-breakers lie at the heart of any switchgear installation.
However, as well as being extremely safe and reliable they must also be able to ensure sustained economy and long service life. Consequently, the demands made upon circuit-breakers are stringent:
- Dielectric strength
- Reliable making and breaking of the conducting path
- Constant arc-quenching capacity during short-circuits - throughout their whole service life
- Powerful, maintenance-free operating mechanisms
Siemens high-voltage circuit-breakers offer optimum technical and economical solutions for every possible need. Depending on the particular field of application and the voltage level involved they can be equipped with various different types of operating mechanism:
- Stored-energy spring mechanism
- Hydraulic mechanism
and arc-quenching systems:
- Self-compression principle
- Puffer principle
Both dead-tank and live-tank circuit-breakers as well as gas-insulated switchgear (GIS) feature identical components.
Self Compression Principle
Utilizing the energy of the arc
The 3AP high-voltage circuit-breaker ensures optimum utilization of the thermal energy of the arc in the interrupter unit.
This is achieved through the principle of self-compression that was patented by Siemens in 1973.
Since then the technology of self-compression has undergone considerable further development. Lately, the practice of using the energy of the arc to quench it has become ever more popular such that, when a fault is being cleared, the amount of operating energy required can be reduced to that simply needed to produce the mechanical travel of the switching contacts. So, since the amount of operating energy required is very small, the stored-energy spring operating mechanism can be a compact, low-energy unit.
Mode of operation
The current path is formed by the terminal plates [(1) and (8)], the contact support (2), the base (7) and the moving contact cylinder (6). In closed state the operating current flows through the main contact (4). An arcing contact (5) acts parallel to this.
Breaking operating currents
During the opening process, the main contact (4) opens first and the current commutates on the still closed arcing contact. If this contact is subsequently opened, an arc is drawn between the contacts (5). At the same time, the contact cylinder (6) moves into the base (7) and compresses the quenching gas there. The gas then flows in the reverse direction through the contact cylinder (6) towards the arcing contact (5) and quenches the arc there.
Breaking fault currents
In the event of high short-circuit currents, the quenching gas on the arcing contact is heated substantially by the energy of the arc. This leads to a rise in pressure in the contact cylinder. In this case the energy for creation of. the required quenching pressure does not have to be produced by the operating mechanism. Subsequently, the fixed arcing contact releases the outflow through the nozzle (3). The gas flows out of the contact cylinder back into the nozzle and quenches the arc.
Puffer Principle
Arc-resistant twin graphite nozzles
In the case of 3AT high-voltage circuit-breakers a contact system incorporating twin graphite nozzles ensures constant arc-quenching characteristics and constant dielectric strength, regardless of the amount of pre-stressing, i.e. the number of breaking operations and the current being switched. The twin graphite nozzles are arc-resistant and so have a very long service life. This means that the interrupter unit is exceptionally powerful . Another important advantage of the puffer principle using twin graphite nozzles is that the arcing chambers work at a slight positive pressure during the quenching process. As a result this means that small amounts of operating energy are sufficient. The arc plasma is of comparatively low conductivity and this has an additional beneficial effect on the making and breaking capacity.
For special applications too:
The specific properties of the twin nozzle system are beneficial for restrike-free switching of low inductive and capacitive currents. Thanks to its high arc resistance the system is especially suitable for the breaking of certain types of fault such as those close to generators.
Mode of operation:
1 Breaker in On position
The current path assemply is formed by the two terminal plates, the first fixed tube (1), the moving contact (2) and the second fixed tube (1). The tube ends constructed as graphite are quenching nozzles. The moving contact (2) comprises spring-loaded contact fingers that are attached to the puffer cylinder (4) arranged in a ring. The puffer cylinder (4) contains an annular piston (3). The moving contact (2), puffer cylinder (4) and piston (3) form the moving part of the break chamber.
2 Precompression
The piston (3) and puffer cylinder (4) are moved in opposite directions by the operating rod and couplers (5,6). The moving part is driven by an operating rod to the effect that the SF6 pressure between the piston and the puffer cylinder (4) increases. The moving contact (2) moves with the puffer cylinder (4) towards the open position.
3 Quenching
When the contacts separate, the moving contact tube (2), which acts as a shut-of valve, releases the SF6. An arc is drawn between one nozzle and the contact tube (2). It is driven - in a matter of milliseconds - between the nozzles by the gas jet and its own electrodynamic forces. The puffer cylinder (4) encloses the arc-quenching arrangement (1) like a pressure chamber. the compressed SF6 flows radially into the break and is discharged axially through the nozzle.
4 Breaker in Off position
After arc extinction the moving contact tube (2) moves into the open position.
Stored Energy Spring Mechanism
The design of the operating mechanism of 3AP high-voltage circuit-breakers is based on the stored-energy spring principle. The use of this type of operating mechanism for the voltage level up to 420 kV was made possible by the development of a self-compression arcing chamber which only needs a small amount of operating energy.
Mode of operation:
Key advantages at a glance:
- Uncomplicated, robust construction with few moving parts
- Maintenance-free
- Compact design in a non-corroding aluminium housing
- Vibration-isolated latches
- Load-free uncoupling of charging mechanism
- Ease of access
- 10,000 operating cycles
Installation and Commissioning
We provide installation and commissioning on request. We are available 24 hours worldwide.
- installation
- commissioning checks
- diagnostics
- spare parts
- failure detection and repair
24h standby duty for the types 3AP, 3AQ and 3AT
Phone: +49 30 386 26659