08-05-2014, 11:25 AM
The 3AP1/2 High-Voltage Circuit-Breakers Now Applicable for 550 kV
High-Voltage Circuit.pdf (Size: 1.76 MB / Downloads: 167)
Decades of our experience in high-volt-
age switching technology go into the
design and production of the 3AP1/2
circuit-breakers which set an interna-
tional trend. We are a powerful partner
for our customers and a competent
supplier of attractive products and so-
lutions at competitive prices with the
high standard of quality that Siemens
is known for. We comply with our cus-
tomers’ demands for reliability, safety
and cost-effectiveness and serve them
throughout the world. No matter what
your application is, the 3AP1/2 circuit-
breakers provide the best solution for
your requirements every time.
The Modular Design
The self compression arc-quenching
principle is applied in our 3AP circuit-
breakers.
The arc-assisted interrupter unit of the
3AP circuit-breaker utilises the energy
of the arc during opening for an optimal
arc quenching, allowing to reduce the
operating energy to a minimum. Our
circuit-breakers for the voltage range
72.5 kV up to 300 kV have one inter-
rupter unit per pole and up to 245 kV the
circuit-breakers are available with a com-
mon or a single-pole operating mecha-
nism. 3AP high-voltage circuit-breakers
from 362 kV up to 550 kV are equipped
with two interrupter units per pole.
Breaking operating currents
During the opening operation, the main
contact (2) opens first, and the current
commutates to the still closed arcing
contact. During the further course of
opening the arcing contact (3) opens and
an arc is drawn between the contacts. At
the same time, the contact cylinder (5)
moves into the base (6) and compresses
the SF6 gas located there. This gas com-
pression creates a gas flow through the
contact cylinder (5) and the nozzle (4) to
the arcing contact extinguishing the arc.
Breaking fault currents
In the event of interrupting high short-
circuit breaking current, the SF6 gas is
heated up considerably at the arcing
contact due to the energy of the arc. This
leads to a pressure increase in the contact
cylinder. During the further course of
opening this increased pressure initiale a
gas flow through the nozzle (4) extin-
guishing the arc. In this case, the arc en-
ergy is used to interrupt the fault circuit
breaking current. This energy needs not
to be provided by the
operating mechanism.