Purpose of circuit switcher
- A circuit switcher is a switching device like a circuit breaker. It interrupts the power flow.
- It is typically installed on the high voltage side of the transformer.
- Historically the fault interruption capability was lower (~5kA) and therefore was only operated for faults occurring on the load side of the transformer. New-generation switchers can interrupt up to 40kA, making it comparable to a circuit breaker and therefore can be operated for faults occurring on the
sourceand load side.
- Circuit switchers may also be installed at the transmission line terminal. Normally, motor-operated disconnects are installed. However, when opening, the line charging current magnitude can overwhelm the interruption capabilities of the whip of a disconnect. A switcher when sized correctly, using its SF6 chamber, can safely interrupt the line charging current.
Cost of circuit switcher
- 345kV 1600A switcher: ~$200,000
- 138kV 1200A switcher: ~70,000
Lead time to procure circuit switcher
- ~18 weeks for a 138kV unit
- ~28 weeks for a 345kV unit
Information on cost and lead time is for your general knowledge only. Contact vendor with your equipment specifications for actual figures.
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