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518 Legrand PDU User Guide
Unbalanced Current Calculation
Unbalanced current information is available on 3-phase models only. This section explains how Legrand
PDU calculates the unbalanced current percentage.
Calculation:
1. Calculate the average current of all 3 lines.
Average current = (L1+L2+L3) / 3
2. Calculate each line's current unbalance by having each line current subtracted and divided with the
average current.
L1 current unbalance = (L1 - average current) / average current
L2 current unbalance = (L2 - average current) / average current
L3 current unbalance = (L3 - average current) / average current
3. Determine the maximum absolute value among three lines' current unbalance values.
Maximum (|L1 current unbalance|, |L2 current unbalance|, |L3 current unbalance|)
4. Convert the maximum value to a percentage.
Unbalanced load percent = 100 * maximum current unbalance
Example:
Each line's current:
L1 = 5.5 amps
L2 = 5.2 amps
L3 = 4.0 amps
Average current: (5.5+5.2+4.0) / 3 = 4.9 amps
L1 current unbalance: (5.5 - 4.9) / 4.9 = 0.1224
L2 current unbalance: (5.2 - 4.9) / 4.9 = 0.0612
L3 current unbalance: (4.0 - 4.9) / 4.9 = -0.1837
Maximum current unbalance:
Maximum (|0.1224|, |0.0612|, |-0.1837|) = 0.1837
Current unbalance converted to a percentage:
100 * (0.1837) = 18%
Ways to Probe Existing User Profiles
This section indicates available ways to query existing user accounts on the Legrand PDU.
With SNMP v3 activated, you get the "user unknown" error when the user name used to authenticate
does not exist.
Any user with the permission to view event rules can query all local existing users via JSON RPC.
Any user with the permission to view the event log may get information about existing users from the log
entries.
Any authenticated users can query currently-existing connection sessions, including
Webcam-Live-Preview sessions, which show a list of associated user names.
