Floating 10 Minutes Average Overvoltage; Ansi 81H Overfrequency, 81L Underfrequency - ComAp MainsPro G99TT Global Manual

Mains decoupling protection relay
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8.2 Floating 10 minutes average overvoltage

The unit calculates floating average of the measured voltage in each phase over 10 minutes interval. If any of
the three phase values crosses the threshold set by
flashes and counter of voltage disturbances is incremented. As the Last Trip record, the message "Vavg" is
displayed. The protection stage is blocked for the first 10 minutes after power-up of the unit.

8.3 ANSI 81H Overfrequency, 81L Underfrequency

The frequency value measured on phase L1 is compared with the preset limit of overfrequency or
underfrequency. When any of the preset thresholds is crossed, the appropriate LED signal is issued by LED f
and the output
f Sig (page 67)
MainsPro G99TT 1.0.0 Global Guide
Image 8.1 Voltage hysteresis for overvoltage
Image 8.2 Voltage hysteresis for undervoltage
Avg V> [V] (page
moves to fault-indicating position immediately. If the frequency keeps out of
57),
TRIP (page 31)
is issued, LED U
34

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