GE PACSystems RX3i User Manual page 14

14
GFK-2748C
Subject
Reverse Power Threshold
VI Imbalance
Setting Programmatic
Parameters
Power Factor
The Reverse Power Threshold affects Grid 1 and Grid 2 differently:

For Grid 1, the Reverse Power alarm will be triggered if a circuit's active power
exceeds the Reverse Power Threshold for a time period longer than Reverse
Power Delay.

For Grid 2, the Reverse Power alarm will be triggered if a circuit's active power
falls below the Reverse Power Threshold for a time period longer than Reverse
Power Delay.
The VI Imbalance Alarm compares voltage phases to voltage phases, and current
phases to current phases within a grid. No comparison is made between grids. If any
voltage varies from the average of all three voltages, or if any current varies from the
average of all three currents (by more than the VI Imbalance Threshold) for longer
than the VI Imbalance Delay, that grid's VI Imbalance Alarm is set.
Example 1:
VI Imbalance is set to 20%, VA1 = 126V, VB1 = 90V, VC1 = 124V
The difference between VB1 and the average of the three voltages is greater than
20%, so the VI Imbalance alarm will be set.
Example 2:
VI Imbalance is set to 25%, IA2 = 4.2A, IB2 = 3.6A, IC2 = 5.5A
The difference between IC2 and the average of the three currents is less than 25%,
so the VI Imbalance alarm will not be set.
Proficy Machine Edition Hardware Configuration parameters are entered as Floating
Point numbers in engineering units. Changing the same parameters programmatically
(using %AQ offset 1 and 2) requires the use of 16-bit Integers which vary from the
Floating Point numbers by factors of 10. Refer to GFK-2749 for details on how to
change configuration parameters in Run Mode.
Although the PSM reports power factor information using three decimal places, the
information is only accurate to two decimal places.
RX3i Power Sync and Measurement System
Description