GE Frame 6B GT with 3rd Party Control system software instead of MKV.

Hi there,

Hope you all are safe in pandemic situation.

We have GE frame 6B Gas turbine with MarkV control system. Recently we are thinking about control system up-gradation. Is it possible to replace MarkV with 3rd party software from SIEMENS/ABB/Schneider?
 
Hi there,

Hope you all are safe in pandemic situation.

We have GE frame 6B Gas turbine with MarkV control system. Recently we are thinking about control system up-gradation. Is it possible to replace MarkV with 3rd party software from SIEMENS/ABB/Schneider?
Hi there,

You can make what we call. Retrofit not upgrade as it is not same thing for such control systems..
I advise you to contact Emerson as they offer reliable and good solution for GE controls systems replacement /retrofit...

One question... Why you do 'pt go for a Mark6e upgrade...

Cheers,
James
 
Thanks for your prompt reply. Yes, Mark6e should be the first choice in our case. But we are thinking about competitive price.
Thank you for you reply....
You better search for OEM as Emerson which equipment proved to improve reliability... Than looking for low cost equipment which can lead to failures sometimes...
Cheers
James
 
SaberMPS,

To begin with, you wouldn't be just buying third-party software--you would be buying hardware, programming software, configuration and programming by some company (usually called a 'control system integrator'), removal of the existing turbine control system hardware, installation of the new control system hardware, commissioning of the new system, and check-out of the control system functions and operation of the turbine and auxiliaries.

The topic of using any PLC (Programmable Logic Controller) or PAC (Programmable Action Controller) to control and protect a combustion turbine has been covered many times before on Control.com. It is certainly possible, and it has been done with widely varying degrees of success. A GE Mark* turbine control system is a purpose-built control system--and that means its designed to control and protect turbines and turbine auxiliaries ("high-speed rotating equipment" per many standards organizations). A PLC or PAC is not a purpose-built system--it can be used in a warehouse for automating stock control and storage, in a meat-processing plant for controlling the equipment used in the process, for controlling a waste-water treatment plant, for controlling a pharmaceutical-manufacturing facility, for controlling a paint factory, etc.--and one would not choose a GE Mark* turbine control system for any of these applications. Again, that doesn't mean a PLC/PAC can't be adapted to use for controlling and protecting turbines--but it requires a person or people who are experienced and knowledgeable about controlling and protecting such equipment, and the various types of inputs and outputs (field devices) used in the control and protection of such equipment.

A turbine control system, particularly for a combustion turbine, primarily controls the speed of the turbine and driven device in order to prevent overspeed and the possible catastrophic consequences of an overspeed. In addition, the the turbine control system also controls the amount of torque (load) being produced by the turbine in order to have a smooth process (electric power generation, or high-pressure pumping, for example). This can be called the "governor" function of the turbine control system, and includes an overspeed protection function as well. The governor functions are, by far, the more difficult functions to implement in a PLC/PAC. THIS is what takes knowledge and experience to properly implement to provide smooth and stable operation of the turbine and auxiliaries for producing torque (load).

The bulk of the turbine control system operate turbine-, and in some cases, driven device auxiliaries--pumps, fans, solenoids, level control, and some protective functions--such as vibration protection, flame detection protection, overtemperature protection (Lube Oil; exhaust temperature; bearing metal temperatures; etc.), pressure protection (low- or high pressure), level monitoring, starting means control, cooldown control, and so on. These functions can be called "sequencing functions." These are the easier functions to implement in a PLC or PAC.

Many of the input and output devices used on a turbine are not typically used in many industrial processes where one would find a PLC- or PAC-based control system. For example, vibration sensors (either velocity ("seismic") sensors or proximity sensors) are not typically found in many applications where PLCs or PACs are used. Neither are flame sensors (flame in the case of fuel being burned inside a combustion chamber). GE-design heavy duty gas turbine also use bipolar electro-hydraulic servo-valves for positioning hydraulically operated control valves and axial compressor inlet guide vanes (IGVs). These are -10 mA to +10 mA devices--NOT 4-20 mA devices. Further, most of the control valves and the IGVs employ LVDTs (Linear Variable Differential Transducers) to provide position feedback; these devices require approximately 7.0 VAC RMS for excitation (power supply), and they produce a differential voltage output on the order of approximately 0.70 VAC RMS to approximately 3.50 VAC RMS for position feedback, which has to be scaled in the control system. (Most industrial processes which use linear position indication use 4-20 mA transmitters of one form or another, and the majority of these devices cannot withstand either the temperatures or the vibration which can be experienced on a combustion turbine.) For example, Siemens Step 7 PLCs are used as the basis for Siemens turbine control systems--BUT, there are special, proprietary controllers and associated software that only Siemens can obtain and use to make the Step 7 as close to a purpose-built turbine control system as possible.

So, this means the supplier will have to EITHER change field devices (and many don't know the temperature/vibration conditions on a turbine) OR they will have to find and use converters of some sort or another--which can introduce time lag ("latency"), single points of failure, or require additional steps and procedures for field calibration, maintenance and replacement. Many Siemens control systems used for turbine control by third-party control system integrators employ LOTS of converters and proprietary card developed by or for the control system integrator(s).

One of the oft-stated reasons for using a common PLC or PAC is the ready availability of both parts and service, as there are usually lots of technicians familiar with common PLC- or PAC-based control system. As for the hardware (parts), many PLCs and PACs do not have to deal with high-speed rotating equipment (such as turbines) and so special, and often proprietary, printed circuit cards have to be sourced for the governing functions (speed control and overspeed protection). And, while there are many people familiar with these common PLCs and PACs--there are few knowledgeable and experienced in using them for turbine and auxiliary control and protection.

Another oft-cited reason for wanting to use common PLCs or PACs for turbine control is that it is often said the turbine OEMs have "closed" control systems, meaning that the programming of some control and protection functions is not "open" to be easily viewed and troubleshot. GE turbine control programming (called sequencing; or CSP (Control System Program); or application code) has graphical representations (based on relay ladder diagram functionality in most cases--which has been around for decades and is STILL a functional and acceptable means of programming a turbine control and protection system) which can be used to follow signals into, through and out of control "blocks" (algorithms). And, the graphical elements used in these blocks are documented in some of the GE turbine control manuals (though few people actually take the time to see exactly what is in the manuals--if they can't find it in a minute or two, they slam the manual shut and declare the Mark* a "Closed and unfriendly" control system--which is far from the actual truth).

Would a PLC- or PAC-based control system be cheaper than a GE Mark* turbine control system? The initial cost would probably be less. But, when you consider that most implementations of PLC-/PAC-based have problems during installation, commissioning and check-out, and this leads to schedule over-runs which means lost production and revenue--which are rarely properly attributed to the new turbine control system--the real cost of a PLC-/PAC-based control system can be higher than a GE Mark* system (though GE has had execution problems with their Mark* turbine control systems as well).

So, for a successful project changing over to a new turbine control system (from ANY manufacturer!) it is very important to understand the knowledge and experience of the people who will be configuring and programming the control system for controlling and protecting a turbine and auxiliaries, AND the knowledge and experience of the people who will be installing, commissioning and checking out the new turbine control system. (Check-out in this case means ensuring starting, acceleration, synchronization, loading/unloading, Droop Speed Control, exhaust temperature control, shutdown, cooldown, water-washing (if applicable)--all of these functions and sequences--work properly, in most cases, that they work as they worked with the old turbine control system. And, that they all work smoothly and stably and transition between schemes automatically when they should.)

THIS is the really hard work of properly choosing a new turbine control system supplier--asking for references and contacts of past turbine control system projects from the potential suppliers, AND then calling or emailing those references/contacts to get their impressions of the project and its success. This is NOT easy, and it's difficult calling or contacting someone one doesn't know. BUT, this is the best way to predict success of a turbine control system change-over (upgrade; retrofit; whatever you want to call it). Past performance is the best predictor of future success.

It is also helpful to know what the after-installation service and support has been for previous PLC-/PAC-based turbine control systems.

Do not simply choose a turbine control system based on either the hardware or the software. To properly choose a turbine control system AND it's supplier, one needs to know about the knowledge and experience of the people who will be programming the control system, as well as the knowledge and experience of the people who will be installing, commissioning, checking-out and even servicing the control system (at least during the warranty period). Even if your mind is made up that you don't want a GE Mark* turbine control system. Do the due diligence required, and you will be much happier.

Hope this helps!
 
Hi there,

Hope you all are safe in pandemic situation.

We have GE frame 6B Gas turbine with MarkV control system. Recently we are thinking about control system up-gradation. Is it possible to replace MarkV with 3rd party software from SIEMENS/ABB/Schneider?
There has been Installations to Replace MKIV, MKV Controllers that I have some knowledge of.. One was a GE Frame 7EA Water Injection Nox Controlled machine with a MKIV that is now Controlled by a Triconex Governor, Foxboro/Triconex interface to the DCS...Triconex on the GE Gas Turbine, (Heat Recovery Steam Generator) HRSG is Foxboro/Schneider BOP (Balance of Plant).. Triconex has extensive Gas Turbine control experience as being an after market Controller developed in the Houston Texas area. Triconex gained their experience in the Oil. Gas Refineries around that area with several Field Engineers in the 1980's up to the present time 2021. Foxboro has a lot of experience on Boiler Controls (HRSG)....Both are Schneider Electric products now.... There is also an Emerson Ovation System that has been used to do the same Controls, Gas Turbine, BOP... The 1st system mentioned Schneider was done before I retired by myself and several other's on a Public Utility machine in Central Florida....The Emerson conversion was done over by Orlando in Central, Florida by another Power Generation utility....I do agree with David_2 on many levels, you better have extensive knowledge when Converting to some other Platform of Controls.. Do not buy 3rd party equipment without absolute knowledge that what you are getting has been proven and tested. Many Converters, Logic installations in a GE System that have to now be done by whatever Platform you are now thinking about Purchasing. Water Wash System, Water Injection, Speed Control, Vibration, Gas Fuel Measurements, Liquid Fuel Measuring, Redundant Logic Controllers to name a Few ***We had a Conversion done back in the early 90's that was a Grey Box that had a Modem and many Converters installed on the GE Frame V Turbine...It was a Headache. It was built in someone's Garage and was a Mystery with only 1,2 people who knew what was in that Grey Box. You had to call them and they would login remotely and give you limited support which usually turned in to a Site visit. Do your Due Diligence up front or you will find yourself in many Problematic situations on the other side. Hope this Helps you with your decisions. Good Luck, BobM Lakeland, Florida
 
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