GE Industrial Solutions Galaxy Verification - Manual (Page 52)

Galaxy Power System Verification Procedures
3 - 8 Galaxy Millennium Controller Performance Verification Procedures Issue 3 January 2008
High Voltage Shutdown Test, continued
Serial Rectifiers There are three requirements for a serial rectifier to shut down upon a
controller-initiated High Voltage Alarm:
• The plant voltage must be above the level set for HV at the front
panel path: <MENU>
→ CONFIG → THRESH.
• The rectifier must be delivering a current exceeding 10% of it's
capacity.
• The rectifier's current output must be unbalanced by more than 10%
from the average output currents of the other rectifiers. Because this
is difficult to achieve in a simulation test of properly functioning
serial rectifiers, even with load share disabled, rectifiers are tested
one at a time rather than as a group. Slightly different test
procedures are used for special applications in batteryless plants.
Note: In an active plant with serial rectifiers the plant High Voltage
(HVSD) test can be performed with only one rectifier in operation, in
order to satisfy all three conditions mentioned above.
Serial rectifiers have their own internal restart circuits that will function
3 times before the rectifier locks itself out and initiates a High Output
Rectifier Fail Alarm to the controller. If there is a sufficient interval
between restart and a subsequent shutdown the rectifier resets its restart
counter.
The controller initiates a restart signal a few seconds after the first RFA
(HO) alarm is received. After the second RFA (HO) is received, the
controller waits 5 minutes before sending one additional restart signal.