The digitally controlled KSQ331x2 provides both visual presentation of relative speed and phase angle relationship, and output signal necessary to permit check synchronising between two systems.
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.
There is lamp indication for reference source present (BUS PWR) and incomer status (GEN PWR).
KSQ331x2 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. 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 setable limits and retention time 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:
KSQ331x2 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 KSQ331x2 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°.
