Integration projects most often are justified as investments that pay off over time. Those shiny new communication interfaces and that extra engineering work promise to be worth it because of improvements to come down the line in productivity, visibility and readier decision-making. But sometimes a system supplier's integrated approach can also mean lower initial costs that pay off immediately—in hardware, in software, in engineering hours—compared with the old way of doing things.
With ABB's System 800xA, system designers and end users gain access to an electrical control and process automation system that comes effectively "pre-integrated" and tested. Greenfield plants and brownfield retrofits can both have their cake and eat it too, reducing upfront costs even as operational savings and performance benefits accrue over time.
As the domain of electrical control has come to rely on Ethernet and other standard, non-proprietary network protocols over recent years, system suppliers such as ABB have in turn been able to eliminate many of the hardwired connections and custom interfaces necessary only a few years ago.
Ethernet-based connectivity means no I/O—and no hardwiring—is required for communication among intelligent electronic devices (IEDs) as well. At one large industrial facility, peer-to-peer networking of IEDs cut an estimated 110 kilometers of cabling. And for a refinery retrofit, 24 marshalling cabinets were eliminated in favor of a single cubicle. Fewer wires also mean fewer terminations, lower installation costs, and improved organization within substation cubicles. Further, fiber optic networks mean that communication links can run closer to busbars without risk of electromagnetic interference.
Engineering, test effort streamlined
All this means reduced hardware, installation and commissioning costs as well as streamlined system engineering effort. Fewer representative configurations, or typicals, can be more safely tested and commissioned back at the switchgear assembler or factory rather than at the plant site. Indeed, adoption of a "bay typical" philosophy can substantially reduce factory acceptance test (FAT) and commissioning time, according to Leandro Monaco, ABB global product manager for electrical integration. "It took perhaps a full day to test a first bay typical," Monaco says of a recent project. "But after that we could test eight others of the same typical in a single day."
Future system flexibility also improves. For example, even after the plant is up and running, IEC 61850 enables GOOSE-based interlocking among switchgear cubicles to be added through software configuration—saving time and keeping workers out of harm's way. Plus, any late configuration changes can be readily replicated via software across multiple typicals.
ABB's Monaco relates how in one recent project, the ability of IEC 61850 networks to gracefully accommodate on-the-fly engineering changes helped to avoid a lengthy commissioning delay. The electrical team realized during commissioning that one critical interlock between the transformer and incomer bays was missing, affecting all 30 medium voltage transformers on site. To overcome the problem, engineers simply mapped two GOOSE variables between the transformer IED and incomer IED. The change was tested and then replicated over the network to all of the IEDs involved.
Alternatively, 60 I/O points would have needed to be hardwired (two for each transformer), including the addition of new I/O modules or the changing out of several already tested IEDs that didn't have spare I/O capacity. With IEC 61850 networking, this late change took an hour; without IEC 61850 networking, the delay would likely have run into days.
Meanwhile, most process automation system architectures in use today already use Ethernet for controller communications and for integration with host-level systems. This Ethernet backbone complements automation-specific protocols such as PROFINET, PROFIBUS and FOUNDATION fieldbus for digital field device integration. With both process automation and electrical control systems converging on Ethernet, then, it's not too hard to envision a system like ABB's System 800xA, wherein IEDs and process controllers are part of a common communications infrastructure. And while an Ethernet physical layer is the common thread, network management technology such as virtual local area networks (VLANs) are used to appropriately segment and secure network traffic.
Smaller footprint, fewer spares
Such a unified system yields immediate cost benefits in terms of system footprint. Floor space is often a critically important consideration for space-constrained applications such as off-shore oil and gas platforms, and for plant expansions and retrofits where new equipment may need to abide by the constraints of pre-existing cabinets and control rooms.
A unified host-level architecture also means that both process and electrical data can be presented on the same engineering, operator and maintenance workstations, possibly reducing the number of consoles necessary while simultaneously boosting the flexibility and capabilities of those that remain.
Inventory costs are reduced, since fewer types of common spare parts are needed. Common engineering and configuration tools mean less training and higher productivity for system designers as well.
Speedier project execution
Less engineering, installation and commissioning effort also added up to speedier project execution for E.ON's hydroelectric power plant in Flåsjö, Sweden. The ability to quickly and cost-effectively retrofit the site's aging electrical and process automation systems with an integrated system was key to ABB winning the recent project, the first in a comprehensive overhaul of E.ON's hydroelectric plants along the Ljungan River.
Only six months elapsed from when the contract was signed until the new system was up and running at Flåsjö. Now, the plant's single, integrated system consists of a unified user interface, a common toolset, and a new connection to the company's remote control center in Sundsvall. The unified System 800xA implementation, which among other things handles turbine control and vibration monitoring, now provides remote access to substation data such reactive power, voltage and current as well. And, when something does need human intervention, maintenance crews arrive equipped with the information, tools, and spare parts they need to effect a complete and rapid fix.