Allen-Bradley 1407-CGCM-DLR User Manual page 52

Chapter 3 CGCM-DLR Unit Operation
52
Soft Start Mode
CGCM-DLR unit Soft Start mode provides for an orderly build-up of generator
voltage from residual to the voltage setpoint in the desired time with minimal
overshoot. When the system is in Soft Start mode, the CGCM-DLR unit adjusts
the voltage reference that is based on the Soft Start Initial Voltage and Soft Start
Time.
The Soft Start Voltage Reference
that shows soft start initial voltage at 30%, soft start time at 8 seconds.
Figure 29 - Soft Start Voltage Reference
If the generator is not up to speed when the soft start begins, the voltage increases
but only to the level determined by Volts/Hz limiting. When the unit is
operating in FCR mode, soft start operates as it does in the AVR mode. The field
current, rather than the generator voltage, is the controlled parameter.
To activate soft start mode:
• The Soft Start Initial Voltage (tag SoftStart_InitLevel) and Soft Start
Time (tag SoftStartTime) parameters must be set.
• Excitation enabled (tag SoftwareExcEn = 1).
• Remote Excitation Enable On (discrete input).
• FCR mode not active (tag AVR_FCR_Select = 0).
• Engine idle bit is set (tag EngineIdle = 1).
Rockwell Automation Publication 1407-UM002B-EN-P - February 2019
illustration is a graph for the voltage reference