User`s manual

RX3i Power Sync and Measurement System 11
GFK-2748
Subject
Description
Scaling for PT and CT Ratios
The IC694PSM001 module reports the voltages and currents measured at the
IC694ACC200 terminals. Therefore, the application logic must correct for PT and CT
ratios to reflect the actual power grid voltages, currents, powers and energies.
Example:
Using 480V:120V PTs requires the application logic to multiply the reported voltage
values by 4. Using 100:5 CTs requires the application logic to multiply the reported
current values by 20. Since power and energy combine voltage and current, the
reported power and energy values must both be multiplied by 80 (4 x 20).
ANSI Alarm Delays
All ANSI alarm delays apply to both setting and clearing the alarms. A delay of 10
seconds means the grid must be in the alarm state for 10 continuous seconds before
the PSM will set the alarm bit; clearing the RelayCloseOK bit and opening the relay
outputs (if the grids were synchronized). Once the alarm is set, the alarm condition
must be eliminated for 10 continuous seconds for the alarm to be cleared.
Relay Output Options
The isolated, bipolar relay outputs are redundant. Both relay 1 and relay 2 follow the
RelayCloseOK %I offset 7 bit from the PSM. They can be connected in parallel to
increase the reliability of closing, or in series, to increase the reliability of opening, to
suit the needs of the application.
Voltage Configuration
The Voltage Selection in the Proficy Machine Edition Hardware Configuration must
match both the physical cable connection to the IC694ACC200 terminal assembly
and the %Q offset 2 (Grid 1) and %Q offset 18 (Grid 2) configuration bits. Refer to
GFK-2749 for proper wiring and configuration information.
Reverse Power Threshold
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.
VI Imbalance
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.
Setting Programmatic
Parameters
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.
Remote or Expansion Racks
When the PSM module is in an expansion or remote rack, and the main rack is
powered separately, the CPU may not regain communication with the PSM after loss
and recovery of power to the main rack, while the expansion rack remains powered.
Power Factor
Although the PSM reports power factor information using three decimal places, the
information is only accurate to two decimal places.