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If the "extra duct length" increases inlet and/or exhaust pressure drops, then it will have some impact on performance. It would be minimal if it is straight length, more if there are bends. You should go back to the supplier for answers.

The "V1 COIL CURRENT(R), V1 COIL CURRENTS(S), and V1 COIL CURRENT(T)" are the currents through the servo controlling the main steam inlet valve (V1), from the R, S and T controllers in the Mark VI. Ideally, they should all be the same, although in the real world there are usually small...

Unless you have other reasons for locating the Mark VIe control cabinet in your central control room, it would be much more cost effective to put the control cabinet in the local control compartment and just locate the HMI (operator interface) in the Central Control Room. That would leave you...

Cv is the (liquid) flow coefficient for a control valve. The flow equation is: Q = Cv * SQRT(deltaP/G) where: Q = flow in gallons(US) per minute deltaP = the differential pressure across the valve in PSI G = specific gravity of the liquid at the flowing conditions

> And i Forgot to say that the unit is working on Ovation system by Emerson Is the Ovation system controlling the Frame 7 GT directly or is it a DCS, with a data link (Ethernet?) to a Mark V or Mark VI GE turbine control?

GE sets the loading rates so as to maximize the operating life of the equipment. Or, perhaps, so as to not unduly shorten the equipment life. They also recognize that the end user would generally like to be able to change loads as rapidly as possible to respond to demand changes. For a...

> We are having steam pressure, steam flow, for drum level differential > transmitter. with the help of this we want to do two element control. Why do you want to do something that is not going to work? Steam flow, without feedwater flow doesn't help. You will be better off just using single...

If FIRE mode is selected from shut down condition, when START command is given, the gas turbine will roll off, purge and fire. After firing, fuel will be reduced to warmup setting. The turbine will remain in this condition until either ACCELERATE or AUTO is selected. The speed is not controlled...

> It is not possible to control the speed of a GE-design heavy duty gas turbine below 95% of rated speed with a GE > Speedtronic turbine control system. GE does not want an operator to accidentally stop acceleration at a > critical speed which could cause high vibration to damage the unit...

A couple of comments: 1. In GE, we usually referred to combined cycle as those applications that used the gas turbine waste heat to produce steam for driving a steam turbine that in turn drives a generator to produce electricity. Where the gas turbine waste heat was used for other purposes...

Perhaps if you knew what we used to call the inlet water sprays it would help you to understand: Evaporative coolers. The spraywater evaporates and cools the inlet air temperature (due to the latent heat of vaporization).

My recollection on this subject is that the gas and steam turbine displays can all be changed at once as per CSA's description. I can't add any more to help on that. The conversion was done in CIMPLICITY, not in the SPEEDTRONIC - the data inside the turbine controls stays in English units as...

GE would typically open the bypass damper on the 63EA high exhaust pressure alarm. The logic for that would likely be in the HRSG controller rather than the gas turbine control. It has been a long time (over 20 years) since I worked on any unit with a bypass damper, but back then we always put...

Mambo, The settings likely to change are those for the SRV P2 control and the various FSR constants (minimum, maximum, and others). I cannot tell you what the new settings will be - you will need to get them from GE, after you have provided a current fuel analysis. They will feed the...

The reduction in heating value of the gas fuel most definitely makes a difference! If this is a "permanent" change, you will need to contact the turbine supplier to find out what is required - likely new fuel nozzles and SRV and GCV trim, along with revised control settings. You may also be...

CSA, I did say "fairly" constant. That is also probably not accurate - I forgot to consider the impact of the IGV position on compressor discharge pressure. And, with DLN systems, there are different flow paths as the combustion mode changes. But my basic thought process was that once...

Voyager2, The SRV does NOT control turbine speed. The SRV controls P2 (intervalve) pressure as a function of turbine speed. This, in turn, maintains a fairly constant pressure drop across the GCV.

Sean, You state: "One correction that DCS remote control to MKV is not 4-20mA but a hardwired." A 4-20mA signal is a hardwired analog signal. Another hardwired possibility is hardwired contact Raise and Lower command signals. Also possible is a data link, which may use "hardwired" copper...

> Pre-Selected Load Control <b>usually</b> can only be active when the unit is in "local" (AUTO) mode. CSA, At least up until I retired, when GE supplied the overall combined cycle plant control, we did make use of Preselected Load Control to implement (remote) dispatch load control. We...

I think you really need to get GE involved in this. It sounds like you may need secondary frequency response, which has been done at some combined cycle sites in Spain. However, this can involve essentially derating the unit to leave room for loading above (the derated) base load limit. Back...