Rolling And Peak Value Demands; Rolling Demand - Areva MiCOM P125 Technical Manual

P12y/EN AP/D32
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7. ROLLING AND PEAK VALUE DEMANDS (P126 & P127
The MiCOM P126 and P127 relays are able to store the 3 phases rolling average and
maximum subperiod values. The description and principle of calculation are given bellow.
7.1

Rolling demand

The principle of the calculation of the rolling demand value for IA, IB and IC currents is
following:
•
Calculation of the average of the RMS values on a "Rolling Sub Period" period.
The setting of the width of the period "Rolling Sub Period" is in the "RECORDS/Rolling
Demand/Sub Period" menu.
Setting range: from 1 to 60 minutes.
•
Storage of these values in a sliding window
•
Calculation of the average of these average values (sliding window values) on the
number of "Num. of Sub Periods" periods
The setting of the number of Sub Period "Num of Sub Periods" in the "RECORDS/Rolling
Demand/Num of Sub Per" menu.
Setting range : from 1 to 24.
Display of the first result in the MEASUREMENTS menu only after the storage of "Num of
Sub Periods" periods. The 3 phases Rolling average value are
displayed :
•
Rolling Average IA RMS
Rolling Average IB RMS
Rolling Average IC RMS
The calculation is reset by either "hand Reset" (by key _ ) without use of password, or a
remote command.
NOTE:
A modification of the settings (either "Rolling Sub Period" or "Num of Sub Periods"
parameter) reset the calculation.
Example:
Sub Period = 5 mn
Num of Sub Period = 2
At the end of the Sub Period 2 :
Rolling average value = (average value 1 + average value 2)/2
At the end of the Sub Period 3 :
New Rolling average value = (average value 2 + average value 3)/2
In case of loss of power supply the rolling demand are not stored.
Application Guide
MiCOM P125/P126 & P127