ABB UNITROL 1020 - Page 154

Chapter 6 - Operation 
146 3BHS335648 E82 UNITROL 1020 User Manual
TP
Signal Name
Scaling
I-shift
13
Frequency injection point
±12.5%
0
14
Power injection point
±200%
4
15
LeadLag injection point
±12.5%
1
16
PSS Status
Bit 0: PSS selected
Bit 1: PSS active (contributing)
Bit 2: PSS blocked by Power
Bit 3: PSS blocked by Voltage lever
Bit 4: PSS blocked by frequency gradient
bits
0
In order to get normalized gain for the measuring transfer function using analog outputs, the I-shift
parameter must be used. The table above shows a possible setup of the I-shift parameter in order to
get normalized gains.
If multiple machines are connected to the same step-up transformer, the user can apply a common
step command to all AVRs simultaneously. This allows testing the PSS and measuring more clearly
the increased damping with a step response.
The user has to enable the common step at all AVRs. The command is given only at one AVR and
is distributed over RS-485 lines to all other AVRs. A common step on all machines is applied within
1ms.
Below extract shows how the common step can be enabled.
During the time this is enabled, the VDC communication will be disabled
If the Common Step Enable button is selected, this status is shown in the setpoint adjust window
(indication turns green).