Turbine automation is a specialized segment within the automation business that is still not dominated by mainline DCS or PLC systems, but remains the domain of more specialized systems. This situation persists for both business and technical reasons. Turbine OEMs prioritize new turbine business over automation system retrofits from the business standpoint. Yet because turbines last lounge than automation systems, older machines inevitably need replacement automation systems sometime during their operating life.
When the time comes to retrofit, turbine owners must decide if they will restrict their supplier choice to just the turbine OEM or will accept systems and services from other providers. They must give priority to selecting high-reliability equipment, high-performance, and a service organization with an excellent track record and deep expertise in this very specialized application, if they consider other suppliers. This ARC Brief discusses the experiences of cogeneration plant and a major energy services provider working with RTP Corporation’s automation equipment in demanding turbine control applications.
Medium and large turbines have been a niche application for automation, one that is not suited perfectly for either DCS or PLC-based automation systems. Most large turbines are still controlled by specialized automation systems designed specifically for turbo-machinery control, instead of general-purpose DCS or PLC systems. The DCS and PLC power system has mushroomed in the years since they were introduced. Why have they had trouble penetrating into automation of turbo-machinery?
There are a number of good reasons. First of all, turbine control is a quite specialized application that requires special components. For instance turbine speed sensors are often redundant, magnetic speed sensor inputs used for both speed control and over speed protection. In addition to more conventional sensors, turbine automation systems must interface with flame scanners, vibration sensors, and linear variable differential transformers (LVDTs), as well as magnetic speed pickups, all of which must be scanned rapidly.