Answer / vijay

Before Synchronisation mainly three conditions
(voltage,speed/frequency & Phase sequence) has to be
checked which are within the limits. Reason to monitor when
any one on this parameters found not in unique, DG set's
not getting synchronised.
If the synchronisation happened in unconditional status, it
causes unbalance current will flow in the operation and
load sharring is not even. To eliminate this kinds of
occurence Dark lamp test was carried out before execution.

Answer / kj

Answer one is mostly correct. Two other factors are important. 1) the winding type (e.g. 2/3 or 5/8) as this can affect circulating neutral current. 2) phase angle at time of synchronising must be within limits to prevent high currents to pull DGs into synch.
For answer two - load sharing equipment can allow DGs of different ratings to be used in parallel. Frequency is important not RPM. The number of poles in an alternator can vary requiring a different RPM for the same frequency.
Another important factor iis governor response to load changes

Answer / benchalli nagaraj

BOATH THE DG'S ARE EQUAL RATING(KVA)
BEFORE SYNCHRONISING THE TWO DG'S TO CHECK 1)BUS VOLTAGE
2) FREQUENCY 3) RPM

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