Circuit Switcher: Learn the Purpose, Cost, and Lead Time to Procure

Circuit switcher
Figure 1: Circuit switcher

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 source and load side.
Circuit switcher
Figure 2: Circuit switcher for transformer protection, installed on high voltage side
Circuit switcher on high side of transformer
Figure 3: Another instance of a circuit switcher for transformer protection. Image credit: First Energy, Penelec Power.
  • 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

  • 35kV 600amp 25KAIC capacitor switcher: ~$45,000
  • 69kV 600amp 25KAIC capacitor switcher: ~$50,000
  • 138kV 600A 25KAIC capacitor switcher: ~$70,000
  • 138kV 2000A 40KAIC circuit switcher: ~$40,000
  • 230kV 3000A 40KAIC circuit switcher: ~$85,000
  • 345kV 1600A 40KAIC circuit switcher: ~$160,000

Note: The cost includes the price of structural steel.

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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Circuit Switcher: Learn the Purpose, Cost, and Lead Time to Procure 1

Substation Major Equipment

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Aleen Mohammed

Aleen Mohammed

Registered Professional Engineer | MSEE
Skillset: Substation Design | Power System Studies | Arc Flash Study

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