KSQ333x2 Series

  • Precision check synchronoscope, sector principle
  • Speed raise/lower relay outputs
  • Bi-directional synchronising
  • Integral voltage differential protection, adjustable
  • Synch-on-hold Function
  • "Easy view" status presentation
  • Generator speed reference (analogue output)
  • System status output
KSQ333x2 provides both visual speed rotation, phase angle relationship and raise/lower speed relay signals necessary to achieve automatic check synchronising of two different system voltages.

KSQ333E2 is the standard and it takes the auxiliary voltage from the monitored voltage on terminal 3 & 4.
KSQ333G2 have separate auxiliary supply on terminal 19 & 20.

The synchronising relay will close when the incomer (generator, busbar, etc.) voltage and phase angle have been within the limits during the set retention time.

A green lamp (CB close) indicates the close command to the breaker.

There is lamp indication for reference source present (BUS PWR, only when generator is powered) and incomer status (GEN PWR).

A green lamp (VOLT OK) is lit when both voltages are within the set limits. 

While the generator is running close to synchronising speed the synch-on-hold function can inhibit synchronising. This feature allows the operator to determine the moment to enable synchronising. Open link between terminal 7 & 8 to inhibit. LED "CB CLOSE" flashes during inhibit condition.

KSQ333x2 can be used both for single and three phase systems. Any two phases (or phase-neutral) can be used for synchronising as long as it is the same two phases on both side of the breaker.

The unit is meant for manual and semi-automatic synchronising only since there is no compensation for the breaker closing time.

For automatic synchronising, the KSQ104x2 ”SPOT ON” principle should be used to obtain compensation for breaker closing delay.

User settable voltage limits, retention time, phase angle and pulse rate and width on the rear.

The analogue -10/0/+10mA output signal can be used as speed reference to a generator controller, with polarity and amplitude proportional to frequency difference between the two systems.

System status:
KSQ333x2 is fitted with a system status relay. As standard the unit is powered from generator side (terminal 3 & 4), when power is ok and unit is working correctly the relay activates. It will release on alarm or when unit is not powered. Separate auxiliary supply is needed for continuously system status.
Normal operation                : Closed contact
Alarm condition/unpowered  : Open contact

System "S" the sector synchronising principle
The KSQ333x2 is a low differential bi-directional check synchronising relay.

The synchronising relay closes when the incomer (generator, busbar, etc.) frequency is close enough (diff 0,018 - 0,83Hz) to stay within the phase angle sector (S) for the set retention period (t).

Sector synchronisation is the classic alternative for applications which allow synchronisation accuracy and duration of synchronisation process to be interrelated. There is no compensation for the breaker closing time.

Approximate synchronisation accuracy relative to 12 o’clock position (Df) can be calculated by the following formula:
Df = (S : 360) / t (secs)
Example: Set phase angle (S) to 10 degrees and retention time (t) to 500mS to obtain an accuracy of Df:
(10/360) / 0,5 =  0,055Hz

If the phase angle limit is set too low and retention time too high for very low differential synchronising, it can be difficult to achieve synchronisation. If there is a continuously fluctuating load between the two systems (for example to synchronise against a shaft generator when a vessel is in rough weather), the KCQ104x2 "SPOT-ON" principle is more suitable.

The "phase angle" setting on the rear of the unit refers to the total phase angle sector (S), centred about 0°. Hence a setting of 10° means the sector spanning from -5° to +5°.

Note: The CB Close LED will flash when unit is ready for synchronising, but inhibit input is open or synchronising mode is not selected.
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