2010-09-07 - Field experience over the last decade has proved ABB made Disconnecting Circuit Breakers (DCBs) to be a revolutionary concept for improving substation availability and reliability while significantly lowering environmental impact and substation footprint. The DCB design is based on conventional live tank circuit breakers and fulfils the function of one circuit breaker and two disconnectors.
Significant reduction in maintenance and failure outage
DCBs give a higher reliability of the disconnecting function since the primary contacts are protected from pollution. Availability calculations based on cigré statistics for failure and maintenance rate shows a clear outage decrease for solutions utilizing the DCB technology. From availability calculations, looking at the substation HV switchgear, up to 91% outage decrease for maintenance and over 50% outage decrease for failures has been found when utilizing DCB technology.
Reducing environmental impact equivalent to removing an average of 5 cars
LCA, Life Cycle Analysis studies of HV switchgear have shown that the major part of the environmental impact is related to the energy losses during the service life. Energy losses for the two alternatives of 145kV equipment that is DCB and the conventional solution of CBs + 2DCB as were calculated over the life period. The study showed that the energy savings per bay with DCB during 40 years of service corresponds to almost 700 tons of CO2, or around 17,5 tons per year.To put the values in perspective, it may be noted that an average car will emit around 3 tons of CO2 per year that is by replacing one conventional CB + 2DC combination with a DCB CO2 savings equivalent to removing 5 cars can be achieved. The DCB technology is a recipient of the Swedish National Power Grid environmental prize.
Simplification of substations
When used in a substation, the DCB replace the combination of circuit breaker and separate disconnectors. Due to low maintenance requirements, high reliability and the fundamentals of the of the DCB technology mentioned above, it is also possible to simplify the substation configuration compared to other substation setups and technologies. Additional savings are found in less landscaping, fewer foundations, steel structures, less control cables, less civil work, fewer transports, etc. These simplifications reduce the overall environmental impact of the substation during manufacture, construction,and service life. The overall result of using DCB technology is considerable and comparisons between different substation setups shows space savings ranging up to ~70% in the switchyard.
More information
| To read more about the field experience and life-cycle studies refer to the attached technical paper on this page. For a practical demonstration watch the video-link attached. |