Circuit Breaker(CB)are designed to switch On & Off the circuit. Under a fault condition; No sooner it receives the command to Open, It opens the circuit but while doing so the CB goes through tremendous stresses and contact are opened to Arc. All this can be reduced using a Controlled Switching. SCOPE in association with Vizimax, Canada offers a Controlled Switching Device (CSD) for MV/HV/ EHV/UHV Circuit Breakers, SynchroTeq series, is the one and only “Manufacturer Agnostic” solution, applicable to either brand new or existing equipment.

This Point on wave operates with intention to have minimum stress on CB while opening or closing keeping the primary function of the CB to switch the circuit in minimal time and without affecting the Grid.

When SynchroTeq Plus receives a CLOSE command, a time delay is initiated, awaiting the first zero-crossing of the phase A voltage for synchronization of the C/B mechanical operation. Should no zero-crossing be detected within the pre-set time delay, controlled switching is aborted and a three-phase random CLOSE is executed if allowed. Should a zero-crossing occur within the pre-set delay and providing no failures are detected, the SynchroTeq Plus sends controlled CLOSE commands to each phase.

The computed time delays are measured from the reference zero-crossing and the time is adjusted to account for environmental factors, measurement sand variations in the C/B characteristics of each phase.

Best Switching strategy for Closing

Load Type R Y B
Capacitor Bank Yg 90° 210° 150°
Capacitor Bank Y and D 30° 120° 30°
Shunt reactor Yg 90° 210° 150°
Shunt reactor Y and D 60° 60° 150°
Transformer Yg- Yg 90° 210° 150°
Transformer Yg- D 90° n*90° n*90°
Line 120° 150°

Best Switching strategy for Opening (Current 0)

Load Type R Y B
Capacitor Bank Yg 90° 210° 150°
Capacitor Bank Y and D 90° 180° 180°
Shunt reactor Yg 90° 210° 150°
Shunt reactor Y and D 90° 180° 180°
Transformer Yg- Yg 90° 210° 150°
Transformer Yg- D 90° 210° n*90°
Line 90° 210° 150°


  • Capacitor Banks
  • Shunt Inductors
  • Power Transformer

Advantage of using Controlled Switching Device

  • Can be used on any technology of circuit breaker
  • Can manage the energization of power transformers based on the residual flux
  • Advanced C/B timing compensation
  • Fast response time
  • Huge event/waveform memory capacity (2000 Events)
  • Waveforms recordings are COMTRADE compatible
  • Simple and secured web interface
  • Remote support
  • Compatible with IEC 61850, DNP3.0 and MODBUS

The SynchroTeq unit improves the operating conditions of the circuit breaker:

  • It reduces the possibilities of re-strike and re-ignition
  • It reduces the inrush current and optimize the arcing time, and therefore reduce the contact wear on the circuit breaker

Nothing is worse than random closing: therefore, SynchroTeq improves the situation!
The SynchroTeq unit is 100 times more accurate and repeatable than a typical circuit breaker:

  • The SynchroTeq control timing is done using a 10 microsecond resolution
  • The SynchroTeq+ alarm detection and feedback measurement is evaluated using a 100 microsecond resolution.

Isn’t a digital electronic system more accurate and repeatable than a mechanical system such as a circuit breaker?

The SynchroTeq unit records the event and waveforms during the opening and closing operations, therefore it is used as a circuit breaker diagnostic tool:

  • If something goes wrong with the circuit breaker, alarms are generated
  • SynchroTeq records all the alarms an operation, including the waveforms data of the CB operation


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