Background:
This is for KNPC. We have four units - mechanical drive fr 5002c. Control system is Mark 6 (TMR).

Unit # A - The unit was running, normal shutdown initiated to check faulty gas detectors in Turbine and filter House compartment.

FYI, almost 1 day back, faulty VCMI of another Unit # 3 was replaced with the VCMI of the Unit. Since customer was keen on starting that Unit# 3.

So now, For Unit # 1, Control is simplex since Only S and T are in control, R - Fail mode due to the VCMI.

Customer wanted to start the unit. Forced l3comm io for a start pass and started the Unit. Removed force

Now, VPRO [z] had diagnostics as
321 - g1/tnl_os_rpm
201 - l4etr1_fb voting mismatch
200 - l4etr2_fb voting mismatch
99 - Sol # 1 Voltage mismatch
100 - Sol # 2 Voltage mismatch

VTUR [T]
225 - tnl_rpm

Fault code 321 of VPRO [Z] and 225 of VTUR [T]was gone/reset after LP shaft attaining 70% of its speed. SP set at 70% (Before loading)

Q1) Suspect Protection is giving a Trip to the solenoids l20fg, l20fl. True/False?

Q2) Did the Emergency Trip relays failed on TREG?

Q3) Believe Protection is alos on simplex now. (Only VPRO X,Y) True / False?

Q4) Is it advisable to run the machine or inform the customer to Stop.?

Please your valued suggestion and advises are highly requested.

If customer agreed to stop, advise on what all to check, what all to replace etc..

Regards,
ARF

 

Hi,

I hope KNPC must be doing well in Kuwait. Which unit MarkVI is in FAIL state? It is Unit1 or Unit3. I believe they have 4 Frame-5 compressor drive.

I am not sure if you are talking about X or Z-VPRO and also not sure if you are talking about Unit#1 only. The reason for this is in your case Unit#1 R0-VCMI is in failed state due to which all its PTRs (PTR1, PTR2) and ETRs (ETR1, ETR2) are in dropped condition (De-Energised). So that means its VPRO that is X-VPRO'S ETR1 and ETR2 must be dropped. Hence as you described if Z-VPRO is producing this diagnostics which means the Z-VPRO ETR1 and ETR2 are dropped and now you have X and Z-VPRO ETR1 and ETR2 are in dropped condition and the unit should trip. I am not sure how your unit is running with this condition.

If this diagnostics are on X-VPRO they are obvious and they are all because the R-Rack VCMI is not in the Controlling state, due to which its VPRO that is <x>-VPRO has dropped all its ETRs. By looking at your diagnostics alarms you seems to use 2/3 PTR1,2/3 ETR1 and 2/3 PTR2,2/3 ETR2 to energise the trip solenoids (Gas Fuel and Liquid Fuel). At present your <X>-VPRO ETR1 and ETR2 is in the de-energised state. Basically these diagnostics alarms tells that the ETRs are dropped .So whichever VPRO is producing these diagnostics its corresponding ETRs are dropped. The reason for this could be many :

1. If that VPROs VCMI is not in controlling state.

2. If the VCMI is in controlling state then the issue could be with the VPRO istelf.May be you can swap the VPROs to check this.

3. The TREG board may be having some issue.

4. The connecting cable between the VPRO and the TREG baord may be loose or bad.

If the diagnostics alarms are on X-VPRO (which should be the case here) there will not be any issue at all and unit will continue to run, but but but.......you are on the threshold of a trip if any other rack S or T rack UCVx/VCMI/VPRO card fails. Any one of the single card out of these three can lead to the trip of the unit. So it is suggested to restore the R0-Rack to Controlling state as soon as possible. So the answer your questions depends if you have diagnostics on the X or Z-VPRO. If it is on X-VPRO only followings are the answer and if it is on Z-VPRO I am clueless how your unit is running.

Q1) Suspect Protection is giving a Trip to the solenoids l20fg, l20fl. True/False?

Yes R-VCMI and X-VPRO is trying to trip the trip solenoids.

Q2) Did the Emergency Trip relays failed on TREG?

No they have not failed and this is a normal phenomena in markVI. The ETRs (Emergency Trip Relay) are dropped because its VCMI is not in the controlling state.

Q3) Believe Protection is also on simplex now. (Only VPRO X,Y) True / False?

Yes the control is now simplex and one more VCMI/UCVx/VPRO failure in S and T rack leads to trip of the unit.

Q4) Is it advisable to run the machine or inform the customer to Stop.?

Definitely it is not suggested to run like this, but it is up to the customer how they want to go ahead with this. Sometimes the production loss is huge for which they may not shutdown the unit.

If customer agrees to stop the unit, arrange for a new VCMI card and restore the R-rack to controlling state.

Thanks
MarkVI Guy

 

Hi,

The diagnostics are showing on VPRO <Z>,

As per your info, the unit should trip, but it is not.

When i try to connect to VPRO <X> , i am not able to connect, but with Y,Z yes, i am able to see the diagnostics.

So, you mean that when VCMI <R> has failed, so, its corresponding VPRO <X> has also no link/effect.

I am confused as what to do next. Then how can it run when both X,Z are trying to trip the unit.

Regards,
ARFarooqi