• sensitivity appr. 15...20 %
• harmonic content compared to the fundamental frequency.
The user can fine-tune the transformer settings during the commissioning phase if there are any issues
with the transformer energization.
5
th
harmonic for overexcitation blocking (principle and usage)
When the transformer's primary side voltage increases for some reason, the voltage-frequency (V/
f) ratio exceeds the desing limits and the transformer overexcited very quickly. This may be caused
by two things: a fault in the LV side can throw off the loading and cause a temporary overvoltage, or the
frequency in the network decreases for some reason (e.g. overloading or generation drop). The
differential relay should not trip in either of these cases even though the overexcitation in the
transformer's core result in the primary side measured currents being higher than those on the
secondary side.
Figure. 5.4.27 - 150. Transformer behavior in case of overvoltage caused by overexcitation.
Genera
Generattor Commander
or Commander
Instruction manual
Version: 2.07
© Arcteq Relays Ltd
IM00001
281
Summary of Contents for Generator Commander
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