We are doing the comparison study for the use of DCS in the power industry among major DCS manuf. like Emerson, Honeywell, Siemens, etc.

I would like to know the deficiencies & bottlenecks of each system. Please submit your comments.

 

The best system if they will sell it to you is the Bailey (ABB) Infi-90 system with the Conductor VMS consoles.

 

1] ABB

2] INVENSYS

 

This is an interesting topic - can we get some feedback?

 

we have B&R System at our Power Plant. And Tachincally its performance is Ok.

U may check your local technical assistance and cost affordable to u.

A PLC programmar

 

The ABB here (MOD 300 now migrated to ADVANT) has been in use since early 1990's. Make SURE yours has:

Historian/trending of LOTS of critical points

and

MANUAL controllers on critical loops in case the DCS/UPS ever "accidentally" or on purpose(Y2K) is off. Very useful if you have combined-cycle and/or steam turbine/HRSG's that don't "control themselves" like a gas turbine will when the DCS is missing...

 

I have worked with and on Foxboro I/A and Westinghouse WDPF (now emerson ovation) and Siemens TXP. I find strengths and weakness with both. Most people will tell you that the best DCS is the one you learned first (for me Foxboro). When you make a decision, it is important to remember that implementation is as important as the product. The best DCS that is poorly implemented is no better than a lesser DCS that is well implemented.

My advice is avoid any MS Windows solutions. Stick to Unix for reliability and security. I like all three systems I mention above, but... the TXP underlying system is written in German. A lot of the things your engineer needs to be looking at may be unreadable if you are not fluent in the language. Also sometimes European thought process is skewed from what we view as normal and may be non-intuitive. The third dig on TXP is the OS is SCO unix. SCO is involved in some very questionable legal battles that may need to be considered. Ask the salesman to demonstrate trending and historical aspects. This is an exellent means of troubleshooting. Ease of graphics building and logic design are important during implementation but may not be as important as the operation after plant acceptance.

Hope this helps.

 

I think if you stick with Honeywell or Emerson you will be fine. However, go with another supplier for distributed I/O or distributed control from the DCS. The I/O solutions from these companies are limited and expensive. My recommendation would be to use a company like WAGO for distributed I/O and control through-out the plant. They have the broadest selection and offer a tremendous value for what you get.

http://www.wago.com
or
1-800-346-7245

From Someone Who's Been There

 

Difficult question to answer. No doubt, ABB and Invensys have some nice offerings, but they are tailored to larger scale systems, particularly medium-to-large scale coal fired systems.

There are several hybrids out there that fill the needs of small systems, including coal-fired units, and you have PLC's that are wonderful for auxiliary use, packaged systems, and even turbine control. Today's powerplants are much more diverse in their systems that they once were, and there is no longer the "use this for everything" black box that controlled everything.

Different applications, different solutions.

 

I went through this exercise about a year ago with our company. It is not all that easy to do and requires some study. If you belong to the ISA they have some good resources there to do your evaluation and selection. We looked at Delta V, ABB, Honeywell Plantscape, Foxboro IA, Seimens PC7, and Yokogawa. Our top two were Delta V and Plantscape. There was not to much difference. At the time Honeywell Experion was not out so we did not evaluate it. We chose Delta V. However, my opinion is the Honeywell was the best of all.

Some Delta V issues the interface card to other devices is by DF1 and RS232 (Modbus RTU). The Delta V only operates in Master mode can never be slave. You have to buy the right amount of licenses which I think is an incorrect way to price your product. Be careful of your power supplies. The Delta V does not supply 24 V loop power you have to buy another unit and allow for it in your cabinet design. Just a few to mention.

 

Westinghouse Emerson Ovation is used in the Majority newer plants. Bailey was used more in the Older Plants. Ovation is the easiest to add components to. A good source of information is Leana Chan at Matrikon OPC. They are the prime supplier of OPC for all GE Power Plants.

 

I like the new Siemens PCS7 V6.0 using redundant CPU417-4H, redundant IO's, redundant communication, redundant servers on ethernet ring topology.

This system is very modular, open to any custom developments using C or VB, with fast tasks and five PLC programming packages.

 

Hi

I'm curious as to the criteria that you used. Do you mind sharing some that info/reasoning? Not the company top secrets of course.

Clyde September

 

Why use a DCS, we automated a 50MW geothermal plant from the well head to the 110kV tapchanger with a PLC and a scada inteface, the first time this has ever been done I might add.

The plant works well, PLCs are stable and high reliability, several PCs with operator screens enhance redundancy

 

I think you answered your own question:
"Why use a DCS"
"PLC and a scada inteface, the first time this has ever been done I might
add."

Some companies don't like to be early adopters or trial sites and therefore will go for a tried and tested solution rather than the innovative one.

Chris Jennings

 

SCADA packages like Fix and PLCs have been dong an admirable job for a long time. Note that all Solar gas turbines are now controlled with Rockwell SCADA and PLCs.

 

The above mentioned issue related to serial communication in DeltaV system which is the product of EMERSON PROCESS MANAGEMENT is not correct. DeltaV can function as both MASTER AND SLAVE, when communicate to the external devices through serial communication. Again DeltaV serial communication port is software configurable as RS232,RS422/RS485:HALF/FULL DUPLEX.

Regarding the DeltaV 24VDC Loop power supply:
All the Deltav systems are supplied along with 24 v power supply to be utilised as a loop power supply which would be incorporated into the system cabinet as a default system component by the DeltaV supplier.

 

I beg to differ on the ABB scale statement. I have worked on 25MW gas fired cogen units that most people would say were small and Bio-Pharm prodution suite that were single control node with 2 control cards. Both ABB.

I like the ABB system, but there is alot to be said for PLCs networked with SCADA for historian/reporting and HMI.

 

I would go with Oviation (formely Westinghouse) now Emerson Process Power and Water Management. These guy have vast experience in Power plants all over the world.

Tony Medina