In switchgear, isolating distances in air combined with circuit breakers are used to protect the circuit state in the grid.
developed a device in which the isolating dis-tance 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 additionally as a disconnector - two functions combined in one device.
The DCB was developed on the basis of a higher-rated standard LW circuit breaker to provide the higher dielec-tric properties required. Due to the SF6-insulated discon-nector function there is no visible opening distance any-more. The proper function of the kinematic chain has been most thoroughly verified. The closest attention was paid to developing a mechanical interlock which guaran-tees that the circuit breaker remains in the open position when used as a disconnector.
When this mechanical interlock is activated, it is impossi-ble to close the breaker. The current status of the DCB can also be monitored electrically and is shown by clearly visi-ble position indicators.
Up to voltages of 145 kV, an additional air-insulated earth-ing switch could be mounted onto the supporting struc-ture. Its earthing function has been implemented by a well-established earthing switch with a Ruhrtal designed maintenance-free contact system.
The disconnecting circuit breakers are type-tested accord-ing to class M2 and C2 of IEC 62271-108, a specific stan-dard for combined switching devices.
By combining the strengths of our well proven product portfolio, we can provide a new type of device which ful-fills customers' needs for the highest reliability and safety, while saving space and costs at the same time.