power generation

E

Thread Starter

eskay

Dear CSA and other Mk6 experts..

Ours is a GE Fr5 Mk6 control turbine. We need to switch OFF the 125 V DC Battery power (for change of battery pack which needs switching of Battery charger also). But AC power will remain ON.

In this case,HMI-PC-LAN switches-screen and printer would remain ON. (we do have an UPS for HMI and its accessories).

I need to switch OFF Mk6 controllers and DC power through PDM switches to R-S-T and Protective cores one by one. What is the correct procedure to be followed in switching off power to controller (sequence) and then to switch ON power to normalise the system? Apart from this,Do i have to stop/start any CIM project/TCI etc..

Kindly advice..Thanks.
 
I have not worked with Mark 6 before but I believe the same analogy from Mark 5 should apply.

When the DC supply to the panel is off, all processors would loose the DC supply. HMI is meant for monitoring and operation only. It doesn't do any of the control. As such with or without backup supply to the HMI does not matter if the panel is shutdown.

If you do have an isolation breaker/ disconnect switch for the batteries, the battery charger is not required to be switched off. However if the batteries does not have any isolation breaker/ disconnect switch and you are not "adventures enough" to remove the battery cables on live (that is definitely not one of the good ideas I have done ;) ), then the complete DC supply need to be off.

To do this, you must ensure that the unit is at standstill. This is because if you switch off the panel, it is same as the unit does not have any turbine controller at all. If the unit is H2 cooled, please ensure that the aux seal oil pump is switched to HAND when the unit reaches standstill to avoid unnecessary H2 purging. You may require to install external H2 analyzer to monitor the H2 purity if the H2 panel is powered by the 125Vdc as well. Other pumps may be put into OFF and locked to avoid mal-operation. After completing all these, you may turn off the controllers one at a time. After this, you may notice that all values in the HMI go blank.

After the batteries are replaced and the chargers are normalized, you may switch on the power to each processors. After all processors are up, you may normalise the breakers in MCC.

Please note that I have assumed that the battery bank is not redundant. If you have redundant battery banks, you may perform the battery replacement one at a time. Please check the configuration at your site as if may differ.

The best time to perform this activity in my opinion would be during the unit inspection/ overhaul as the turbine controller would not be in use and none of the parameters would require monitoring from the HMI.
 
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