Arcteq AQ 200 Series, Инструкция по эксплуатации

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For setting of the instant stage should be considered the inrush peak current also, with normal power
transformer the energizing inrush current may be 10 xIn peak, while the measured current is fft- ltered
for fundamental component which is used for differential calculation the found differential current shall
be 50% of the maximum peak current typically. If the setting should be according to theoretical
m margin, then 5 xIn + margin should be considered for the instant stage. For conservative
settings 10 xIn can be used. This value should never cause trips for energizing and yet it will operate
fast on in energisation fault cases (this stage usually is never blocked in application, thus it’s settings
should be considered on absolute differential current possible on normal operation yet it should be
sensitive also for inrush currents especially on energisation cases).
Setting suggestion for this I
di>Pick-up
stage is 6.0 xIn … 10 xIn for sensitive and conservative operation.
Now basic settings for the differential stages are applied and basically the differential protection is
ready to operate. In this example the transformer used is very small, however the formulas presented in
this manual can be applied to any size power transformers. In the TRF module, relay calculates these
settings automatically if so wanted. Relay uses exactly these same formulas for the setting calculations.
AQ-T216
Instruction manual
Version: 2.00
141 © Arcteq Relays Ltd