SFg circuit breaker

Figure 19.16(a) An SFg circuit breaker 123-145 kV, 31.5 kA. It can also be pneumatic or spring operated, depending upon the arc quenching technique adopted and energy required to extinguish 2 the arc (Courtesy BHEL) 3... 

Figure 19.20 Typical design of one pole of a rotating arc SFg circuit breaker...

As a replacement for bulk oil circuit breakers for distribution purposes, vacuum is a rival to SFg. The contact interruption chamber is a sealed unit with a small contact-separation distances (typically, 16mm for 24kV). Choice of contact material is critical since the material affects ... 

Baumbach, J.I. PUzecker, P. Trindade, E., Monitoring of circuit breakers using ion mobility spectrometry to detect SFg-decomposition, Int. J. Ion Mobil. Spectrom. 1999, 2, 35-39. 

A search for other gases/mixtures for use in circuit breakers showed that while no other gaseous medium outperforms SFe in circuit breakers, some gases/mixtures can be considered. The performance ratings (based on the critical interruption current h for a given surge impedance Zq) relative to SFg of some such media are listed in Table III. 

There is a report on the Carbon Membrane Separator for elimination of SFg from gas insirlated electrical utilities [7]. In the electrical power industry 80% of 6,500-7,500 metric t SFg produced worldwide is used as a gaseous dielectric in circuit breakers, gas-irrsulated substatiorrs and switchgear. Besides its high price, SFg is a very potent greenhoitse gas. A possible way to captirre and reuse the SFg in the... 

The two comparatively new type of breakers, vacuum and SFg are exceptions and have gained favour in view of their reliability and durability. For details on these breakers, see Sections 19.5.5 and 19.5.6, which also deal with their switching behaviour and phenomenon of arc reignition. Figures 12.44 and 12.45 illustrate typical power and control circuit diagrams respectively, for a 6.6 kV breaker-operated motor starter. 

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