Rockwell Automation 1407-CGCM Combination Generator Control Module - Manual (Page 121)

Rockwell Automation Publication 1407-UM001G-EN-P - April 2013 121
CGCM Unit Startup Chapter 5
Verify Operation of Limiter Functions and Diode Monitor
Perform the following tests to verify Limiter Functions and Diode Monitor
operation.
Volts/Hz Operation
Perform this test with the generator operating unloaded in Constant Speed mode
and constant voltage AVR mode.
Follow these steps to test the Volts/Hz operation.
1. With the generator circuit breaker open, adjust the prime mover speed
down to just above the configured V/Hz upper knee frequency.
Verify that the voltage remains constant.
2. Adjust the prime mover speed down to below the configured V/Hz upper
knee frequency.
Verify the voltage decreases at the configured upper slope rate.
3. Adjust the prime mover speed down to below the configured V/Hz lower
knee frequency.
Verify the voltage decreases at the configured lower slope rate.
Under-excitation Limiting (UEL) Operation
Perform this test with the generator operating in parallel (droop or PF/VAR
control) with a large power source that is maintaining constant voltage.
Follow these steps to test the UEL operation.
1. Disable the UEL function.
2. Set the online under-excitation limit for 5% VARs into the generator.
3. Adjust the VARs into the generator for 15% at 25% load to create an
under-excited condition
4. Enable the UEL function.
This creates a step change into the UEL limit.
5. Observe the response of the excitation current reported by the CGCM
unit.
6. Adjust the UEL gains as required to obtain the desired stable response.
7. Verify stable performance of the UEL by testing the machine from
25…100% real power loading while under excited.
8. Increase the excitation above the UEL limit.
9. Return the UEL settings to the values determined for the application.