The turbine was synched first time after the upgradtion of MarkV to MarkVIe control system. The turbine was running on Droop mode. It was decided to check the ISO mode and turbine was put on ISO mode. Number of things happened when the ISO command was given.
1. Turbine did not go into the ISO mode.
2. Turbine started to shed off the load.
3. Generator purging was shown on the HMI instead of ISO.
4. The ISO/Droop status of this machine (GT2) is shared with the other machine (GT1). The GT1 showed that the GT2 is still in droop mode.
The turbine was taken into to the droop mode again. It remained stable on the same load(after shedding the load). The logic for putting the turbine into ISO was different from MarkV (YES, this was an undocumented change). Some contacts were present which we were not even used anywhere. We decided to force those contacts to see the results. Again the ISO command was given and the results were same except the point number 4. This time the GT1 showed that the GT2 is in ISO mode.
There were no other process or diagnostic alarms present. What may be the causes of load shedding? What is meant by message "Generator purging"? What may be the possible causes of this message/mode of turbine?
1. Turbine did not go into the ISO mode.
2. Turbine started to shed off the load.
3. Generator purging was shown on the HMI instead of ISO.
4. The ISO/Droop status of this machine (GT2) is shared with the other machine (GT1). The GT1 showed that the GT2 is still in droop mode.
The turbine was taken into to the droop mode again. It remained stable on the same load(after shedding the load). The logic for putting the turbine into ISO was different from MarkV (YES, this was an undocumented change). Some contacts were present which we were not even used anywhere. We decided to force those contacts to see the results. Again the ISO command was given and the results were same except the point number 4. This time the GT1 showed that the GT2 is in ISO mode.
There were no other process or diagnostic alarms present. What may be the causes of load shedding? What is meant by message "Generator purging"? What may be the possible causes of this message/mode of turbine?