GCP, PMS AND DCS INTERFACE

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Thread Starter

RetiredGoblin

Hello everyone,

I am an electrical design engineer in the oil and gas industry. I am currently designing a power generation system that has 3 gas generators (3x50%) philosophy and 1 emergency diesel generator. Because of the large number of loads, I have included a PMS in my design to be able to carry out load-shedding functions SCADA functions, in case a gas generator breakdown or there is a fault. For instrumentation & control purposes, the GCP and PMS will interface with the DCS. My question is this: I know the GCP will interface with the PMS. However, what equipment (GCP or PMS) will interface with the DCS?

My email addy is: [email protected]

Many thanks in advance
 
Hello,

I don't see a description of what the DCS does. Does it just display information from the GCP and PMS? Does it need to issue some kind of commands to the GCP and PMS?

Most of the GCPs I've worked on had generator metering (watt-, VAr-, volt- and ampere meters), synchronization (manual and automatic), generator protective relays, speed/load raise and lower switches, and voltage raise & lower switches along with excitation metering. Most also had generator temperature metering.

PMSs could also issue speed/load raises and lowers, voltage raises & lowers, and some were capable of initiating automatic synchronization of one or more breakers and others could also open generator breakers as well as load breakers (for load-shedding). Some could also start and stop generator-set prime movers, but that's getting quite complicated--not impossible, but very complicated.

DCSs are sometimes used just for monitoring plant operations, but most sites prefer to integrate control as well as monitoring into a single system--usually the DCS.

I would say both the GCP and PMS would have to interface with the DCS, as well as the generator-set controls (start and stop at a minimum). What communication means are you going to use between all these systems? Some type of network, or multiple networks, such as MODBUS TCP, or DeviceNET, or CAN, or some version of an industrial Ethernet--or will it just be discrete signals and analog signals? Or some combination of the two? Some DCSs can speak "natively" to many different smaller control systems via proprietary or open-source protocols/methods. Discrete and analog signals are going to require a LOT of wire and I/O capability.

I would say the choice depends on what the DCS is being used for, and what the communication capabilities of the various systems are--again, because "hard-wiring" the signals necessary for such a large system between these three controllers (depending on their complexity) is going to be complex and require lots of I/O capability in each controller.

So, basically, we don't have enough information to be of much help. Every GCP is not like every other GCP, and every PMS is not like every other PMS, and every DCS is not like every other DCS. And, therein lies the biggest issue--not being able to understand precisely what each system does and is to do, so as to be able to understand how to integrate them. And, again--there was no mention of the generator-set controls (governors).
 
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