Ge frame 5 controlled by hsde after start signal it reach to 1000 rpm then tripped before fuel metering valve open
As a diagnosis we measure the out put signal from the digicon to the valve and find that no order going from the digicon
So does that mean the problem in 16 way out put relay

 

Does it means in the title that unit controls system displaying (HSDE DIGICON) any alarms
If so can you share the alarms messages..

It would be great also to have a control sequence of teh DIGICON..if you need assistance from here...

 

The thing is to know how and why unit tripped ..would be to share here alarms report/diagnostic
To see if any device is in trouble or something is avoiding unit to get FSNL

 

The thing is to know how and why unit tripped ..would be to share here alarms report/diagnostic
To see if any device is in trouble or something is avoiding unit to get FSNL

It display summary trip only when speed pass 1000rpm

 

Not lot of indication so ...

 

absi absi,

ControlsGuy25 is correct; we must have more information. The starting sequence for most GE-design heavy duty gas turbines is pretty similar: purge; fire; warm-up; accelerate; load. Also, we don't know if the machine at your site is a generator drive or a mechanical (compressor?) drive turbine.

HSDE DIGICONs are no longer produced, if I recall correctly--BUT after doing some World Wide Web searching I see there is a company that is or may be still supporting them. They were pretty good control systems, but there weren't a lot of them and the knowledge and experience base for them is probably pretty small. Most of the turbine control discussions on Control.com are about GE Mark* turbine control systems, hardware, software and control philosophies. When someone replaces a Mark* with Some Other Brand (SOB) control system, usually the control system integrator performing the upgrade/retrofit for all intents and purposes "copies" what's currently in the existing turbine control system. That only makes sense, since the turbine was running before with what was in the control system being replaced and it needs to run again with the new control system.

Now, most often, the new control system has a different operating system and requires a different programming method/language/protocol (whatever you want to call it) and so it's not just a copy-and-paste operation to duplicate/copy what was in the existing control system. And, some times, the company purchasing the new control system wants to make a change here or there.

But, the fact remains: During starting, the turbine has to be purged (all possible combustible gases must be "pushed" out of the unit and replaced with air, to avoid any explosion when trying to ignite the fuel). Then once the purge sequence/cycle is complete, the ignition system is usually energized and then fuel is admitted to the turbine combustors (this is a safety sequence so that the ignition system is already working before fuel is admitted, whereas if the ignition system was energized AFTER fuel was admitted there may be some accumulation of fuel that might result in a "boom" of some magnitude, small or large, which is not good for the turbine or exhaust and which can cause higher than normal thermal stresses on the turbine and/or exhaust). Usually, again to reduce thermal stresses on the turbine and exhaust during starting, the fuel is reduced very slightly for a minute or so to allow a small period for the unit to begin warming up, and then increasing fuel flow-rate and the starting means combine to accelerate the unit to rated speed over a period of time (to minimize thermal stresses, again, to the extent possible).

Now, other things happen during this time (motors are started; the starting means is stopped; if the unit has variable IGVs they are modulated open; and at some point the compressor bleed valves are closed; and some auxiliary motors are stopped; etc.).

But, what you DIDN'T tell us was--at what point during the START sequence did the trip occur? And, we get it that in the "Alarm Summary" there was an indication that the unit was tripped--BUT, just about EVERY control system that I've EVER worked with on a turbine will annunciate SOME kind of alarm to indicate WHY the unit tripped. For, example, if fuel was not ignited during a turbine START on a machine with a Mark* turbine control system the alarm "FAILURE TO IGNITE" would be annunciated. At that point, the site personnel need to determine if fuel was actually flowing to the combustors, if the ignition system was working, and if any flame was detected (either by the flame detectors or an increase in exhaust temperature). And, then, using the information they gathered they need to take appropriate action. You haven't told us if you determined that fuel SHOULD HAVE BEEN flowing at that point in the START sequence or not.... You seem to be implying that fuel should have been flowing, but you weren't clear about that.

Usually, a relay output is used to send a signal to allow the fuel stop valve to be opened. Do you know if the fuel stop valve opened or not before the trip?

Usually it's an analog signal of some sort (+/- 10 mA; 4-20 mA; etc.) that is sent to the fuel control valve actuator to cause them to admit fuel to the turbine combustors, and unless the programmers/configurators of the HSDE DIGICON used a relay output to "switch" the analog signal to the fuel control valve actuator it wouldn't go through a relay output--it would be directly connected to the control valve actuator.

So, without being able to understand the configuration of the HSDE DIGICON I am unable to provide much more information. Hopefully, with the information provided above you can work your way through the control system and understand what should be happening during a START and then possibly what did happen when the unit was tripped, and attempt another START (I'm pretty certain more than one START attempt has already been tried, but, were people prepared to watch particular valves and signals to gain information to understand what was happening?)

Anyway, please write back to let us know what you find. It would be most appreciated!

Blessed day.

 

absi absi,

ControlsGuy25 is correct; we must have more information. The starting sequence for most GE-design heavy duty gas turbines is pretty similar: purge; fire; warm-up; accelerate; load. Also, we don't know if the machine at your site is a generator drive or a mechanical (compressor?) drive turbine.

HSDE DIGICONs are no longer produced, if I recall correctly--BUT after doing some World Wide Web searching I see there is a company that is or may be still supporting them. They were pretty good control systems, but there weren't a lot of them and the knowledge and experience base for them is probably pretty small. Most of the turbine control discussions on Control.com are about GE Mark* turbine control systems, hardware, software and control philosophies. When someone replaces a Mark* with Some Other Brand (SOB) control system, usually the control system integrator performing the upgrade/retrofit for all intents and purposes "copies" what's currently in the existing turbine control system. That only makes sense, since the turbine was running before with what was in the control system being replaced and it needs to run again with the new control system.

Now, most often, the new control system has a different operating system and requires a different programming method/language/protocol (whatever you want to call it) and so it's not just a copy-and-paste operation to duplicate/copy what was in the existing control system. And, some times, the company purchasing the new control system wants to make a change here or there.

But, the fact remains: During starting, the turbine has to be purged (all possible combustible gases must be "pushed" out of the unit and replaced with air, to avoid any explosion when trying to ignite the fuel). Then once the purge sequence/cycle is complete, the ignition system is usually energized and then fuel is admitted to the turbine combustors (this is a safety sequence so that the ignition system is already working before fuel is admitted, whereas if the ignition system was energized AFTER fuel was admitted there may be some accumulation of fuel that might result in a "boom" of some magnitude, small or large, which is not good for the turbine or exhaust and which can cause higher than normal thermal stresses on the turbine and/or exhaust). Usually, again to reduce thermal stresses on the turbine and exhaust during starting, the fuel is reduced very slightly for a minute or so to allow a small period for the unit to begin warming up, and then increasing fuel flow-rate and the starting means combine to accelerate the unit to rated speed over a period of time (to minimize thermal stresses, again, to the extent possible).

Now, other things happen during this time (motors are started; the starting means is stopped; if the unit has variable IGVs they are modulated open; and at some point the compressor bleed valves are closed; and some auxiliary motors are stopped; etc.).

But, what you DIDN'T tell us was--at what point during the START sequence did the trip occur? And, we get it that in the "Alarm Summary" there was an indication that the unit was tripped--BUT, just about EVERY control system that I've EVER worked with on a turbine will annunciate SOME kind of alarm to indicate WHY the unit tripped. For, example, if fuel was not ignited during a turbine START on a machine with a Mark* turbine control system the alarm "FAILURE TO IGNITE" would be annunciated. At that point, the site personnel need to determine if fuel was actually flowing to the combustors, if the ignition system was working, and if any flame was detected (either by the flame detectors or an increase in exhaust temperature). And, then, using the information they gathered they need to take appropriate action. You haven't told us if you determined that fuel SHOULD HAVE BEEN flowing at that point in the START sequence or not.... You seem to be implying that fuel should have been flowing, but you weren't clear about that.

Usually, a relay output is used to send a signal to allow the fuel stop valve to be opened. Do you know if the fuel stop valve opened or not before the trip?

Usually it's an analog signal of some sort (+/- 10 mA; 4-20 mA; etc.) that is sent to the fuel control valve actuator to cause them to admit fuel to the turbine combustors, and unless the programmers/configurators of the HSDE DIGICON used a relay output to "switch" the analog signal to the fuel control valve actuator it wouldn't go through a relay output--it would be directly connected to the control valve actuator.

So, without being able to understand the configuration of the HSDE DIGICON I am unable to provide much more information. Hopefully, with the information provided above you can work your way through the control system and understand what should be happening during a START and then possibly what did happen when the unit was tripped, and attempt another START (I'm pretty certain more than one START attempt has already been tried, but, were people prepared to watch particular valves and signals to gain information to understand what was happening?)

Anyway, please write back to let us know what you find. It would be most appreciated!

Blessed day.

Unit goes trip before fuel metering valve is opened but shut off valve opened I measure the signal from digicon to the fuel metering valve and it was OK and also test the valve with external toshiba also was OK the problem is no alarm shown on the innoucer and at the moment that the fuel metering valve should open summary trip in 16 way out put relay of digicon appearance and unit goes trip

 

absi absi,

Another thing you haven’t told us is what fuel the unit is burning.?.?.?

When did this problem start? After a maintenance outage? After a trip from load?

Is it possible there is some kind of ground in the system in some circuit connected to the 16-way output relay? Perhaps the fuel shutoff valve?

What kind of fuel metering valve is being used?

Is the fuel supply pressure good? Could it be too high or too low?

Is the fuel you are trying to start the unit on the normal fuel the unit starts and runs on? For example, does the unit normally start and operate on gas fuel, but you are trying to start the unit on liquid fuel and are experiencing problems? If so, are you sure there is no air in the liquid fuel line? Is the HSDE DIGICON monitoring fuel flow-rate and expecting to see a stable flow but because of air in the liquid fuel supply line there is an extremely unstable flow-rate signal?

I am very familiar with GE-design Frame 5 operation and start-up, but I am not familiar with HSDE DIGICON control systems and this “summary trip” concept. I hope you can understand that I, we, need more information in order to try to help you resolve this issue. In my experience, most—but not all—problems like this are NOT the fault of the control system, but rather the fault of some field device or condition that the control system doesn’t directly affect—like excessively low- or high fuel supply pressure, or air in the fuel supply line(s), or a ground in some circuit connected to the control system. If this problem started after a maintenance outage and some portion of the fuel system was removed and replaced it’s possible the wiring was not properly re-connected or some termination is loose. Or, the air was not fully bled from the system. A typical GE-design Frame 5 burning liquid fuel uses a liquid fuel flow divider to monitor liquid fuel flow-rate and if there is air in the liquid fuel supply system the flow-rate will appear to be very unstable and the GE turbine control system will quite often trip the turbine.

A typical GE-design Frame 5burning natural gas will have two control valves in the fuel system, the first valve, called the Stop/Ratio Valve, or SRV, acts as the fuel stop valve and also serves to reduce the gas fuel supply pressure to a very low pressure upstream of the second valve, called the Gas Control Valve, or GCV, that actually controls the amount of gas fuel flowing to the combustors. If the pressure upstream of the GCV is too high or too low the GE turbine control system will often trip the turbine.

All of the valves described above on a typical GE-design Frame 5 are hydraulically actuated and hydraulic supply pressure is very important. A typical Frame 5 also usually has another protective system called the Trip Oil or Control Oil system that requires the proper pressure to be established to allow fuel to flow and will trip the turbine if the pressure is not correct.

Sometimes when a new turbine control system is installed the fuel control valves are replaced with different valves, sometimes using electric actuators, and if that’s the case at your site we would not know that unless you told us and all we could do—as we are doing now—is suggest what might be the problem on a typical Frame 5. But if the fuel supply system of your unit was modified from normal and you don’t know that or don’t tell us that then we can’t be of much help.

Let’s say I wrote to an Internet forum to ask for help with my watch which wasn’t working. My question might be, “My watch isn’t working. What might the problem be?” You don’t know if I have a mechanical watch or a watch with a battery, or a watch with hands and a dial or a watch with a digital display. You don’t know if my watch is running and just not set to the proper time or if it’s completely stopped. You would have to ask many questions just to know what kind of watch I have and what the problem is or might be. Your question in this forum is very similar—you have a GE-design Frame 5, and it has a non-standard control system which might also mean the fuel system has been modified, too. You also haven’t told us what fuel you are trying to start the unit with, or if the fuel is the typical fuel used to start and run the turbine. You haven’t told us when this problem started—let’s say the problem with my watch started after it was dropped 20 meters into a 0.5 meter deep puddle of water and it was in the water for 3 hours. Would that make a difference to your line of questioning?

We need more information. Just because you are working on a GE-design Frame 5 heavy duty gas turbine doesn’t mean it’s exactly like every other Frame 5–and in fact, yours has a non-standard control system. We can most likely help you—if you give us much more information than you have given us. We are not there standing next to you; we can’t see what you see; we don’t know what you know.Please try to remember this, and provide as much information as you can. Think about my watch problem—what would you need to know to be able to help me fix my watch? What information could I have provided that would make it easier for you to help me with my watch?

Again, we can probably help you—but if we have to ask 50 questions it’s going to take a long time. And this “summary trip” thing is most confusing—most confusing.

 

Absi absi,

Is this ”summary trip” associated with the 16-relay output card (or 16-output relay card)? Is it some kind of "diagnostic" the HSDE DIGICON runs and alarms when there's a problem?

When you say the unit trips--exactly what is happening? Does the fuel stop valve just close but the unit continues to run (spin the shaft with the starting means) and requires an operator to initiate a STOP? Does the START sequence indication go out and the starting means shuts down, meaning the unit begins to coast down to zero speed and cooldown operation (hydraulic ratchet or "turning gear")?

What else is connected to this 16-output relay card (or 16-relay output card)?

Again, when did this problem begin? Was it after a maintenance outage or a trip from load? What might have happened to "trigger" this new behaviour? Was there an especially violent electrical storm (lightning) or a very heavy rainstorm just before this began to happen? Was the control system powered down for some reason and then powered back up again?

Are you sure there are no grounds or shorts in the control system circuitry--particularly connected to this suspect card?

In this response I am asking six things:

1) Is it possible this "summary trip" is related directly to this suspect card you keep referring to?

2) Is the "summary trip" associated with the 16-relay output card (or 16 output relay card)? Or do you think it's some serious process condition (such as low-low fuel supply pressure, or unstable fuel flow, or???)?

3) What exactly is happening when you say the unit "trips?"

4) What else is connected to the relay card you keep referring to? Why do you suspect the relay card has something to do with the problem? Is there a past history of problems with this card?

5) When did this problem begin? Can you think of anything that occurred immediately before the problem began that might have something to do with the issue?

6) Are you confident there are no shorts or grounds in the wiring connected to this control system--particular connected to this suspect 16-output relay card (or 16-relay output card)?

Thanks. Also, please try to end each statement with a period; it's difficult to follow what you are trying to say without reading your replies several times.