Disconnecting circuit breakers (DCB)

Siemens Energy has developed a device in which the isolating distance has been integrated in the SF6 gas compartment in order to reduce external environmental influences. The DCB (Disconnecting Circuit Breaker) is used as a circuit breaker and also as a disconnector – two functions combined in one device. An additional air-insulated earthing switch can be mounted onto the supporting structure for voltages up to 145 kV.

Ask our experts

Main features:

Combination of circuit breaker and disconnector in one device
No visible opening distance due to the SF6-insulated disconnector function
Compact mechanical interlock which guarantees that the circuit breaker stays in the open position when used as a disconnector
Position indicators for monitoring
Optional air-insulated earthing switch (up to 145 kV)

Advantages:

Highest reliability by applying well-proven and established components from Siemens circuit breakers and earthing switches
Highest availability due to reduced maintenance interruptions
Cost- and space-saving solution by combining two devices into one
Minimized costs for transportation, maintenance, installation and commissioning, as well as civil engineering work
Compact and intelligent interlocking and position indicating device for greater safety
From a single source: documentation and technical support, assembly and installation, customer training, 24-hour service

Our DCB family

Like all of our circuit breakers, the core components were taken from our other circuit breakers, disconnectors and GIS product family in line with our proven modular design. The Disconnecting Circuit Breakers are type-tested according to class M2 and C2 of IEC 62271-108, a specific standard for combined switching devices.

The Disconnecting Circuit Breaker for 145 kV has a three-pole operating mechanism with a common base (FG), and a single-pole operating mechanism on separate bases (FI) for 420 kV.

	3AP1 DCB	3AP2 DCB
Rated voltage [kV]	145	420
Number of interrupter units per pole	1	2
Rated power-frequency withstand voltage [kV]	275 or 315	520 or 610
Rated lightning impulse withstand voltage / min [kV]	650 or 750	1425 or 1665
Rated switching impulse withstand voltage [kV]		1050 or 1245
Rated normal current, up to [A]		4000
Rated short-time withstand current (1s - 3s), up to [kA (rms)]		40
Temperature range [°C]	-40 up to +40
Rated operating sequence	0-0.3 s-CO-3 min-CO or CO-15 s-CO
Rated break time	3 cycles
Rated frequency [Hz]	50 or 60
Maintenance after	25 years
Insulating medium	SF6