Basics of synchrocheck function settings

Basics of synchrocheck function settings

These are the basics of setting up the synchrocheck function. For more details refer to IED manual.

Setting up voltage transformer for synchrochecking

To setup synchrocheck function start with setting at least one of the voltage channels as the channel used for synchrochecking. This can be done at Measurement > Transformers > VT module. If 3LL+U4 or 3LN+U4 mode is used, only U4 channel can be set as the channel for synchrochecking/switching. If 2LL+U3+U4 mode is used U3 is also available. Setup the voltage transformer nominals.

Enabling synchrocheck function

Enable synchrocheck function at Control > Controls enabled. After this synchrocheck function is visible at Control > Control functions > Synchrocheck. If you have set any of the voltage channels to "SS" you should see at least one of these options in INFO page:
  1. Use SYN1 = Available when U4 has been set to "SS" mode. Compares voltage status between U4 and selected line-to-line or line-to-neutral voltage.
  2. Use SYN2 = Available when U3 has been set to "SS" mode. Compares voltage status between U3 and selected line-to-line or line-to-neutral voltage.
  3. Use SYN3 = Available when both U3 and U4 has been set to "SS" mode. Compares voltage status between U3 and U4 channels.

Choosing voltage reference

To "SYN1/SYN2/SYN3 reference" parameter choose the voltage reference connected to the synchrocheck voltage channel. Keep in mind that if 3LL+U4 or 2LL+U3+U4 is used and no channel is set to "U0" mode (i.e. no residual voltage is available) line-to-neutral voltage (UL1/UL2/UL3) should not be used.
If SYN3 is used the only option is to compare U3 and U4 voltage.

Setting thresholds for synchronized state

Conditions for synchronized state are set up at Control > Control functions > Synchrocheck > SETTINGS.
  1. SYN1/SYN2/SYN3 conditions: Defines permitted voltage statuses. Image below illustrates LL, DL, DD and LD states. Top figure represents synchrocheck channel (U3 or U4) and bottom figure represents the chosen voltage reference channel.

  2. U live > and U dead < settings define voltage levels for live and dead network states.
  3. U diff <, Angle diff < and freq diff < define the maximum voltage magnitude difference, voltage angle difference and voltage frequency difference.

Using synchrocheck OK status to permit breaker closing

AQ-200 IED synchrocheck OK status (SYN1 OK, SYN2 OK or SYN3 OK) can be used to permit internal breaker control function to close the breaker or to send the OK status to an external unit via output relay.

Using SYN OK to permit AQ-200 object (breaker control function) to close the breaker

When setting up an object (Control > Objects > ObjectX > INFO) set Use synchrocheck to "Synchrocheck in use". Then in the same menu choose SYN1 OK, SYN2 OK or SYN3 OK to Sync.Check status In. Now synchrocheck function status must be OK for the object function to be able to give breaker closing command.

Using SYN OK to permit external unit to give close command

If synchrocheck status OK is used by an external unit go to Control > Control functions > Synchrocheck > IO and set SYN1 OK, SYN2 OK or SYN3 OK to one of the available output relays.


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