SmartClose® Synchronous Vacuum Capacitor Switches

SmartClose® Synchronous Vacuum Capacitor Switches

SmartClose® Capacitor Switches (PATENT PENDING)

Trinetics® synchronous vacuum capacitor switches bring new focus to the synchronous close and zero voltage close capacitor bank-switching applications.

Commissioning time, complexity and cost have been greatly reduced, while the precision and reliability of close on wave form switching has been substantially improved. Automatic self-calibration and durable, restrike-free, maintenance-free switching are just a few of the benefits gained by adding Trinetics® SmartClose synchronous vacuum switches to your capacitor bank applications.

The SmartClose family of vacuum capacitor switches fully conforms to ANSI Standard C37.66-2005.

  • 200A & 400A rating options.
  • 15kV & 25kV; 110kV & 125kV BIL.
  • Best in class C2 restrike free.
  • Long life vacuum interrupter with solid-dielectric insulation for maintenance-free switching.
  • Eliminate the material cost and space required for inrush reactors.
  • Mitigate harmonics and switching disturbances that occur in back-to-back capacitor bank switching and large power capacitor bank switching.
  • One tank device configured for independent pole operation for three-phase applications.

Convert any bank to synchronous close.
The unique design of the SmartClose capacitor switch includes six integral voltage sensors that detect the voltage waveform on both the capacitor side and the source side of each interrupter. A close command issued by a separate capacitor bank controller causes the SmartClose capacitor switch to close each interrupter independently when the voltage difference across each interrupter is zero. A simple close command to the SmartClose will initiate 3 phase zero voltage closing in all circuit configurations. Delta, Wye, Ungrounded Wye, and phase rotations are no longer a concern to the installer.  Zero close functionality is embedded in the SmartClose switch and is enabled and calibrated prior to shipment.

This allows the user to separately select a preferred capacitor bank controller with a range of functionality ranging from lower cost Volt-Time controls to VAR controls. Or alternatively, the switch can be remotely controlled through a separately supplied RTU/PLC controller.
The bottom line? The bank controller decides when the capacitor bank is needed; the SmartClose switch receives that command and performs the synchronous close automatically.

SmartClose Features:

Compatible with existing capacitor bank controllers.

  • Only needs CLOSE or OPEN command.
  • Existing control means no additional training required.

Installation site costs are greatly reduced.

  • Synchronous control sensors integrated into the switch.
  • External wiring and junction box virtually eliminated.

Commissioning costs are dramatically reduced.

  • On-site calibration time eliminated.
  • Time to program system detailed technical parameters eliminated.

Bulky, expensive transient recording equipment eliminated.

  • Performance waveforms can be captured and downloaded to your PC.
  • No external equipment required.
  • Fiber optic link provides isolation and safety from the system.


  • Voltage ratings: 15kV or 24kV
  • BIL ratings: 110 or 125kV BIL
  • Load ratings: 200A or 400A
  • Short time (1 second) : 12,500A
  • Bushings (24kV): 18” terminal to terminal; 19” terminal to ground
  • Voltage sensors: integral, internal and external.  (Not for external use)
  • Operation: Solenoid or emergency manual
  • Aux supply: 50/60 Hz, 120VAC or 240VAC
  • Mounting provision: 3ph pole bracket or substation frame
  • Fiber optic interface for source side voltage sampling during close operation
  • 195 lbs


Synchronous switching, often referred to as “zero-close” switching is a technique that can be used to help eliminate the disturbances that can occur when connecting or disconnecting capacitor banks to an active distribution feeder. When a shunt power factor capacitor bank is energized, during the first cycles of operation the capacitor initially appears as a short on the distribution system. Large transient inrush currents and harmonic resonance can occur which can be disruptive and damaging to other attached equipment and can adversely impact the quality of electric service provided to a utility’s customers.

In applications where large banks are installed near existing sensitive processes or equipment, this disruptive resonance can cause improper operation of variable speed drives, computers, and other sensitive equipment. As a result, industrial processes can be disrupted causing equipment damage, expensive batch loss or even regulatory compliance issues caused by process instability.

Trinetics SmartClose capacitor switches provide consistent best in class performance for synchronous close switching applications. Additional benefits include quick easy commissioning, and “drift-free” performance. 200A and 400A switches are available for 15kV, 25kV and 35kV grounded wye applications.

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