We have two Frame5 LA machines with MarkVie control. recently commissioned. we are using honeywell flame scanners. The #2 and #3 flame indication in HMI is different (#3 shows half of #2 in one unit and vice versa in other unit) 340 Hz and 180 Hz. Also the indication keeps moving and causes voter mismatch diagnosis alarm often. Please advice why the flame indication is different and how can we bring to the same level.
MarkVie flame indication mismatch
- Thread starter iqbal5903
- Start date
Iqbal,
Your post is a little confusing. You say you have two machines, but you don't say if the flame detector problem affects only one unit or both units.
Further, you didn't tell us what fuel the unit is running on when it has the flame detector mismatch.
<b>Most importantly</b>, you didn't tell us when this problem started. If it's not too long after commissioning you should be able to get the packager/supplier to assist with troubleshooting.
Lastly, you didn't tell us what you've done to troubleshoot the problem and what the results of your efforts were.
It's rare for all flame detectors to indicate the same intensity. Presuming the wiring has been confirmed to be good (no grounds; properly terminated shield wires), and that you have tried exchanging the flame detectors or the wiring to see if the problem is the detector or the Mark VIe input, and the low intensity indication remains on the same combustor then the problem is most likely something is wrong either with the sight tube the flame detector is mounted on (angle, or aim, or blockage) or the fuel nozzle (blockage, or excessive clearance, etc.).
And if it is a fuel nozzle issue the exhaust temperature spread will be higher than normal--another parameter it would have been good to have to help analyze your problem.
Another possible problem could be a dirty lens. Again, you haven't told us what you've done to troubleshoot the problem and what the results were.
Also, every flame detector does not produce exactly the same indication for the same flame.
There is no rocket science involved. Just like with all troubleshooting, it's a process of elimination. But it's most likely not a Mark VIe problem.
Please write back to let us know what you find.
And in the future, please try to anticipate the kinds of questions you might be asked. Too much information is better than too little information if you want a quick and concise reply.
Your post is a little confusing. You say you have two machines, but you don't say if the flame detector problem affects only one unit or both units.
Further, you didn't tell us what fuel the unit is running on when it has the flame detector mismatch.
<b>Most importantly</b>, you didn't tell us when this problem started. If it's not too long after commissioning you should be able to get the packager/supplier to assist with troubleshooting.
Lastly, you didn't tell us what you've done to troubleshoot the problem and what the results of your efforts were.
It's rare for all flame detectors to indicate the same intensity. Presuming the wiring has been confirmed to be good (no grounds; properly terminated shield wires), and that you have tried exchanging the flame detectors or the wiring to see if the problem is the detector or the Mark VIe input, and the low intensity indication remains on the same combustor then the problem is most likely something is wrong either with the sight tube the flame detector is mounted on (angle, or aim, or blockage) or the fuel nozzle (blockage, or excessive clearance, etc.).
And if it is a fuel nozzle issue the exhaust temperature spread will be higher than normal--another parameter it would have been good to have to help analyze your problem.
Another possible problem could be a dirty lens. Again, you haven't told us what you've done to troubleshoot the problem and what the results were.
Also, every flame detector does not produce exactly the same indication for the same flame.
There is no rocket science involved. Just like with all troubleshooting, it's a process of elimination. But it's most likely not a Mark VIe problem.
Please write back to let us know what you find.
And in the future, please try to anticipate the kinds of questions you might be asked. Too much information is better than too little information if you want a quick and concise reply.
You say "We have two Frame5 LA machines with MarkVie control. recently commissioned."
These are rather old turbines that would have originally had a fuel regulator control, not a Speedtronic control. So please clarify as to what was recently commissioned. I assume it was the Mark VIe replacing an earlier control, unless you bought an old unit from someone and re-commissioned it with a new control. What was the old control? Regardless, were the Honeywell flame scanners added as part of the retrofit (5001LA machines did not leave the factory with Honeywell flame detectors)? If the Honeywell flame detectors worked with a previous control there is no reason they should not work with a Mark VIe.
What fuel are you running on? Also answer CSA's questions.
These are rather old turbines that would have originally had a fuel regulator control, not a Speedtronic control. So please clarify as to what was recently commissioned. I assume it was the Mark VIe replacing an earlier control, unless you bought an old unit from someone and re-commissioned it with a new control. What was the old control? Regardless, were the Honeywell flame scanners added as part of the retrofit (5001LA machines did not leave the factory with Honeywell flame detectors)? If the Honeywell flame detectors worked with a previous control there is no reason they should not work with a Mark VIe.
What fuel are you running on? Also answer CSA's questions.
CSA,
Flame detector problem is there in both units. One unit #2 flame good(340 Hz) and #3 poor(180 Hz) and in the other unit the flame intensity #3 is good and #2 is poor.
Both run on Natural gas fuel.
These machines were with Hitachi control system and retrofitted with MArkVie controls recently. Commissioned by Hitachi. Problem was there from the beginning, but they could not do anything.
We had replaced both flame scanners with new, but the flame intensity is the same.
There was no change in the field position, tubing etc.,
Strange thing is that one scanner intensity is just half of the other and these readings in the other unit is opposite.
Otised,
Hope I have answered all.
These are Frame5LA machines retrofitted with HIACS5000, Hitachi control system with Honeywell flame scanners. Only the control system is again retrofitted with MarkVie. This job was done by Hitachi.
Thanks
Flame detector problem is there in both units. One unit #2 flame good(340 Hz) and #3 poor(180 Hz) and in the other unit the flame intensity #3 is good and #2 is poor.
Both run on Natural gas fuel.
These machines were with Hitachi control system and retrofitted with MArkVie controls recently. Commissioned by Hitachi. Problem was there from the beginning, but they could not do anything.
We had replaced both flame scanners with new, but the flame intensity is the same.
There was no change in the field position, tubing etc.,
Strange thing is that one scanner intensity is just half of the other and these readings in the other unit is opposite.
Otised,
Hope I have answered all.
These are Frame5LA machines retrofitted with HIACS5000, Hitachi control system with Honeywell flame scanners. Only the control system is again retrofitted with MarkVie. This job was done by Hitachi.
Thanks
Iqbal,
I have one very important question to begin with: Did you ever have any indication of flame intensity with the previous turbine control systems used on the turbines? Or, was it simply a logic signal indicating the presence or the absence of flame, not a logic signal derived from flame intensity?
You say you have replaced the flame detectors with new ones but the difference in intensities is the same. That would indicate to me one of three things.
First, that the problem is one of a true difference in intensity between the two combustors. This is not unusual and frequently occurs on machines retrofitted with new control systems that display intensity instead of just a simple logic "1" or "0" to indicate presence or absence of flame. This can be due to differences in flow-rates of fuel nozzles (which can be as much as 10% or more on a poorly matched set of fuel nozzles).
Second, it could be a problem with the angle of the flame detector sight tube or with a partial blockage of the line of sight (sight path) of the flame detector to the flame "ball". Many times over the years the pipes (sight tubes) the flame detectors are attached to get bent and misaligned over time. Also, I have seen carbon steel pipe used for these sight tubes and it can become internally rusted and occluded and actually "absorb" UV radiation instead of just letting it pass through unobstructed to the flame detector lens.
Some older units also had gate valves installed in the sight tubes for isolating them during on off-line water wash. Sometimes, these also get rusted and worn and cause partial blockage of the line of sight to the flame ball.
Another problem that has occurred is the holes in the combustion liners that the flame detectors look through can be misaligned with the flame detector sight tubes. This can be due to a manufacturing defect, or a liner installation problem.
The point is that the flame detectors have to have a clear, unobstructed line of sight to the flame "ball". I have even seen one unit of a multi-unit site which had some non-OEM combustion liners and nozzles installed in it which caused the flame ball to be a couple of inches downstream in the combustion liner from where it normally was and should have been. And, the other units at the same site did not have exactly the same combustion hardware and did not have the flame intensity problems that the one unit had.
So, if there have been changes to combustion hardware (liners and nozzles in particular) over the years these units have been in service, and if the sight tubes have become damaged or internally rusted or were misaligned during installation of the sight tube flanges, or if the holes in the liners do not line up with the sight tubes, then the flame detectors can have a difficult time seeing the actual flame. And, if the combustion hardware causes the location of the flame ball to be slightly downstream, or even upstream, of it's normal location (which is not right at the tip of the nozzle) then the flame detectors can have an even more difficult time seeing the flame.
Third, this may be a configuration or wiring issue. Geiger-Mueller style flame detectors (which Honeywell flame detectors are) operate at high voltages, 335 VDC is used in GE Speedtronic control systems. The wiring should be run in separate conduits and shielded from other wires; GE classes this wiring as Level 3S (which is a special classification reserved just for these types of flame detectors). The shield drain wires should be properly terminated (in one place only), following normal shield drain wire grounding practices. There is usually a third "earthing" wire coming out of the body of the flame detector, and that is not to be connected to the interconnecting shield drain wire. If anything, it is to be terminated to ground (earth) at the junction box closest to the flame detector, but is not to be connected to any interconnecting shield drain wire.
And, while this is highly unlikely, the ToolboxST configurations of the inputs in the two Mark VIe's could be different. Again, unlikely but one way to verify this would be to simply swap the two pairs of flame detectors wires at the terminal board. If the low intensity was originally at #2 and it stays at #2 after exchanging the wiring, then the configuration of the input is suspect. If, however, the low intensity moves to the #3 input when the wires are exchanged, then that only adds more credence to the theory above that there is in fact a difference in flame intensity or that there is some problem with the sight tube, sight tube angle, or flame ball location.
Again, not every flame ball in every combustor of every unit has the same intensity. They should be closer than you describe, but if this is the first time you've ever had flame intensity indication then you may never have known there was any issue before! This happens a lot.
You still did not respond to the question of exhaust temperature spreads. How high are the spreads? 30 deg C? Lower? 40 deg C? Higher? Because if there is truly a great difference in intensity then there will also be a larger than normal exhaust temperature spread.
If there is truly a flame intensity difference then it will be accompanied by some kind of elevated (increased) exhaust temperature spread. It's that simple. Low flame intensity would indicate a lower temperature flame, and that would show up in higher exhaust temperature spreads.
During a maintenance outage, you can remove the fuel nozzles from the two combustors with the flame detectors. You can remove the flame detectors from the sight tubes. Then you can use a piece of brazing rod to push down through the site tubes to the area just in front of where the fuel nozzle tip would be to see if the two flame detectors are pointed at the same area. You can also look down the sight tubes having some shine a dull flash light up the sight tube from inside the combustion liner to see if they line of sight is clear and unobstructed.
But, I highly doubt this is a Mark VIe controls issue. It's either wiring, configuration (which is a human issue), or misalignment/line of sight issue. But not a Speedtronic controls issue.
So, you have some work to do. Please write back to let us know the results of your efforts.
I have one very important question to begin with: Did you ever have any indication of flame intensity with the previous turbine control systems used on the turbines? Or, was it simply a logic signal indicating the presence or the absence of flame, not a logic signal derived from flame intensity?
You say you have replaced the flame detectors with new ones but the difference in intensities is the same. That would indicate to me one of three things.
First, that the problem is one of a true difference in intensity between the two combustors. This is not unusual and frequently occurs on machines retrofitted with new control systems that display intensity instead of just a simple logic "1" or "0" to indicate presence or absence of flame. This can be due to differences in flow-rates of fuel nozzles (which can be as much as 10% or more on a poorly matched set of fuel nozzles).
Second, it could be a problem with the angle of the flame detector sight tube or with a partial blockage of the line of sight (sight path) of the flame detector to the flame "ball". Many times over the years the pipes (sight tubes) the flame detectors are attached to get bent and misaligned over time. Also, I have seen carbon steel pipe used for these sight tubes and it can become internally rusted and occluded and actually "absorb" UV radiation instead of just letting it pass through unobstructed to the flame detector lens.
Some older units also had gate valves installed in the sight tubes for isolating them during on off-line water wash. Sometimes, these also get rusted and worn and cause partial blockage of the line of sight to the flame ball.
Another problem that has occurred is the holes in the combustion liners that the flame detectors look through can be misaligned with the flame detector sight tubes. This can be due to a manufacturing defect, or a liner installation problem.
The point is that the flame detectors have to have a clear, unobstructed line of sight to the flame "ball". I have even seen one unit of a multi-unit site which had some non-OEM combustion liners and nozzles installed in it which caused the flame ball to be a couple of inches downstream in the combustion liner from where it normally was and should have been. And, the other units at the same site did not have exactly the same combustion hardware and did not have the flame intensity problems that the one unit had.
So, if there have been changes to combustion hardware (liners and nozzles in particular) over the years these units have been in service, and if the sight tubes have become damaged or internally rusted or were misaligned during installation of the sight tube flanges, or if the holes in the liners do not line up with the sight tubes, then the flame detectors can have a difficult time seeing the actual flame. And, if the combustion hardware causes the location of the flame ball to be slightly downstream, or even upstream, of it's normal location (which is not right at the tip of the nozzle) then the flame detectors can have an even more difficult time seeing the flame.
Third, this may be a configuration or wiring issue. Geiger-Mueller style flame detectors (which Honeywell flame detectors are) operate at high voltages, 335 VDC is used in GE Speedtronic control systems. The wiring should be run in separate conduits and shielded from other wires; GE classes this wiring as Level 3S (which is a special classification reserved just for these types of flame detectors). The shield drain wires should be properly terminated (in one place only), following normal shield drain wire grounding practices. There is usually a third "earthing" wire coming out of the body of the flame detector, and that is not to be connected to the interconnecting shield drain wire. If anything, it is to be terminated to ground (earth) at the junction box closest to the flame detector, but is not to be connected to any interconnecting shield drain wire.
And, while this is highly unlikely, the ToolboxST configurations of the inputs in the two Mark VIe's could be different. Again, unlikely but one way to verify this would be to simply swap the two pairs of flame detectors wires at the terminal board. If the low intensity was originally at #2 and it stays at #2 after exchanging the wiring, then the configuration of the input is suspect. If, however, the low intensity moves to the #3 input when the wires are exchanged, then that only adds more credence to the theory above that there is in fact a difference in flame intensity or that there is some problem with the sight tube, sight tube angle, or flame ball location.
Again, not every flame ball in every combustor of every unit has the same intensity. They should be closer than you describe, but if this is the first time you've ever had flame intensity indication then you may never have known there was any issue before! This happens a lot.
You still did not respond to the question of exhaust temperature spreads. How high are the spreads? 30 deg C? Lower? 40 deg C? Higher? Because if there is truly a great difference in intensity then there will also be a larger than normal exhaust temperature spread.
If there is truly a flame intensity difference then it will be accompanied by some kind of elevated (increased) exhaust temperature spread. It's that simple. Low flame intensity would indicate a lower temperature flame, and that would show up in higher exhaust temperature spreads.
During a maintenance outage, you can remove the fuel nozzles from the two combustors with the flame detectors. You can remove the flame detectors from the sight tubes. Then you can use a piece of brazing rod to push down through the site tubes to the area just in front of where the fuel nozzle tip would be to see if the two flame detectors are pointed at the same area. You can also look down the sight tubes having some shine a dull flash light up the sight tube from inside the combustion liner to see if they line of sight is clear and unobstructed.
But, I highly doubt this is a Mark VIe controls issue. It's either wiring, configuration (which is a human issue), or misalignment/line of sight issue. But not a Speedtronic controls issue.
So, you have some work to do. Please write back to let us know the results of your efforts.
iqbal,
Some things to check:
Wiring - check condition and routing of the wiring to the scanners. I recall a problem (many years ago) when the wiring to one of the scanners got too hot and flame indication was lost.
Test - try swapping the connections at the control panel to see if the problem moves. I.e., interchange which terminal board points #2 and #3 are connected to. If problem was on #2 and is now on #3 (as shown on the CIMPLICITY screen), then the source of the trouble is outside the control panel. If the problem stays on #2 the problem is inside the control panel.
I am not sure what type of device is used to read the scanners in your control panel. Initially GE used an amplifier supplied by Honeywell - it was a black box approximately 10 cm x 15 cm x 3 cm mounted on an interior wall of the control panel. More recently, I think GE were using their own equipment. I definitely have no knowledge of what Hitachi uses.
Regardless, it the problem is outside the control, check the wiring. If inside, could be internal wiring or the readout equipment or a setting in ToolboxST.
Some things to check:
Wiring - check condition and routing of the wiring to the scanners. I recall a problem (many years ago) when the wiring to one of the scanners got too hot and flame indication was lost.
Test - try swapping the connections at the control panel to see if the problem moves. I.e., interchange which terminal board points #2 and #3 are connected to. If problem was on #2 and is now on #3 (as shown on the CIMPLICITY screen), then the source of the trouble is outside the control panel. If the problem stays on #2 the problem is inside the control panel.
I am not sure what type of device is used to read the scanners in your control panel. Initially GE used an amplifier supplied by Honeywell - it was a black box approximately 10 cm x 15 cm x 3 cm mounted on an interior wall of the control panel. More recently, I think GE were using their own equipment. I definitely have no knowledge of what Hitachi uses.
Regardless, it the problem is outside the control, check the wiring. If inside, could be internal wiring or the readout equipment or a setting in ToolboxST.
CSA,
The information is very useful for trouble shooting. Thanks in advance.
* Coming to the exhaust tem spread. It is very normal in both units. only 20 oF.
* Cables from the flame detectors are individual shielded cables run separately (but not on conduit).
* One more thing the third wire from the flame sensor is connected to the shield wire near the flame sensor junction box. This will be corrected in the next outage.
*This is the first time we see flame intensity indication. earlier we had only on/off signal. That is why we do not know the earlier flame condition.
* Combustion hardwares are the same.
All other factors you rightly pointed out could lead to the intensity being different.
We will further check the points mentioned in your mail and get back. Thanks
Now coming to "OTISED".
Flame scanner wire is not getting hot.
we will try swapping the wires at the control panel and see the result.
Flame scanner amplifier is the one supplied by GE.
Thanks again.
The information is very useful for trouble shooting. Thanks in advance.
* Coming to the exhaust tem spread. It is very normal in both units. only 20 oF.
* Cables from the flame detectors are individual shielded cables run separately (but not on conduit).
* One more thing the third wire from the flame sensor is connected to the shield wire near the flame sensor junction box. This will be corrected in the next outage.
*This is the first time we see flame intensity indication. earlier we had only on/off signal. That is why we do not know the earlier flame condition.
* Combustion hardwares are the same.
All other factors you rightly pointed out could lead to the intensity being different.
We will further check the points mentioned in your mail and get back. Thanks
Now coming to "OTISED".
Flame scanner wire is not getting hot.
we will try swapping the wires at the control panel and see the result.
Flame scanner amplifier is the one supplied by GE.
Thanks again.
