We started Gas turbine Frame-V machine and taken on auto firing from MARK-Vie. After firing started, speed level was achieved 14HM but it was seemed speed ramp slowly. Machine got tripped on "Starting device tripped" before 14HA speed reached.

We checked in software block and found it was happening on 14HA not achieved. Machine speed increasing was very slowly.

What happen to machine speed ramp slowly.

 

Mr. Gupta,

You did not tell us what kind of starting means is used to purge and help accelerate the turbine; this is a very important piece of information.

You also didn't tell us what fuel the turbine was being started on.

And you didn't tell us what Process- and Diagnostic Alarms were annunciate during the failed start attempt prior to the trip.

But, the most important piece of information is:

<b>WHEN did this problem start?</b>

We presume things were working fine, but something happened just before this problem occurred. Something like a trip from load, or a maintenance outage, or some work on/around the torque converter. Or, a fuel valve servo was replaced and someone felt it was necessary to "calibrate the servo"?

What occurred right before this problem started?

While it would be best to review the application code running in the Mark VIe controlling the Frame 5 at your site, I don't recall seeing a timer waiting for the unit to get to 14HA that would trip the turbine if it didn't reach 14HA in a certain period of time. Usually, if the starting means is an electric motor the motor's protective relay will trip the motor (and the turbine) if the motor windings get too hot (and they are pulling more than nameplate current during starting and acceleration). Also, if the unit begins to decelerate the Speedtronic will usually trip the starting means and turbine on "bog down"--meaning the turbine is decelerating while the starting means is trying to accelerate it (which is bad). (There is usually a process alarm to this effect if it happens.)

If the unit was accelerating slowly (and possibly starting to decelerate) the causes could be:

1) too little torque being transmitted from the starting means through the torque converter to the turbine-generator shaft,

or,

2) insufficient fuel to accelerate the turbine-generator.

So, it's necessary to check the valves and strainers on the torque converter feed and drain (use the handy-dandy Starting Means P&ID) to be sure the torque converter can pass as much torque as it can.

If the Mark VIe is an upgrade from an older control system, it is the source of all evil and is definitely preventing the torque converter from transmitting maximum torque, or preventing the starting means motor from developing as much torque as possible or preventing the same amount of fuel from getting into the turbine as before the problem started.

<b>NOT!!!</b>

Torque converters do wear out. If there are solenoid valves associated with the torque converter they do wear out and sometimes stick. The Mark VIe outputs to any solenoid associated with the torque converter are usually fused, and fuses do fail (though that's not caused by the Mark VIe).

If the starting means is a Diesel engine, it can wear out, and dirty fuel filters have restricted the fuel flow to the diesel on many units. Also, dirty diesel air filters have been known to cause problems for the diesel to develop rated torque (neither is controlled or monitored by the Mark VIe).

As for lack of fuel, well, this is usually a self-inflicted problem. If the unit is being started on liquid fuel the supply pressure/flow can be restricted (not controlled by the Mark VIe). Dirty strainers in the fuel suction or dirty filters on the turbine can be the problem (both usually have high d-p switches to annunciate process alarms for either condition on the Mark VIe.)

If the unit is being started on gas fuel, the fuel pressure and/or flow could be restricted upstream of the turbine (not usually controlled by the Mark VIe.)

If a fuel control valve servo was replaced and/or "calibrated" before the problem that could be the cause (but that would be a self-inflicted problem, not caused by the Mark VIe).

But you need to provide a LOT more information for us to be of any additional help.

Please write back to let us know what you find!