Integrating Automation and Power with IEC 61850

Trends toward integrating electrical, safety and substation automation systems are affecting how we engineer process automation systems and operate process plants.

By Paul Studebaker

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“The worlds of automation and power have collided, and we believe they will collide further,” announced Brandon Spencer, vice president and US Industry Group Manager, Oil, Gas, & Petrochemical, ABB, at ABB Automation & Power World today in Houston.

Continuing on the ABB theme of “better together,” Spencer moderated “The Power of Integration in the Chemical, Oil & Gas Industry” forum, which focused on how trends toward integrating electrical, safety and substation automation systems are affecting how we engineer process automation systems and operate process plants.

Who cares about energy?

“Oil is cheap now, so who cares about efficiency?” asked Larry O’Brien, vice president, ARC Advisory Group. “Especially in the oil & gas industry, there’s an attitude that ‘we make the energy, so we’re not so concerned.’ But industry consumes one-third of all energy, the process industries are the most energy-intensive, and energy is still the industry’s second largest expense (after raw materials). And we expect to need 44% more energy over the next 20 years.”

Motors account for 70% of all energy usage—many industrial motors consume 10 times their purchase price every year. “And while oil is cheap, the electricity price index is at its all-time high,” O’Brien said. Energy remains the industry’s number-one controllable cost, but are you measuring waste? Do you even have a baseline measurement?”

A recent ARC survey shows that 21% of plants have fully automatic energy monitoring systems, but 42% say they have a semi-automatic system, and 26% say they do it manually. Among the same plants, 54% say they could reduce their annual consumption 6-10%, and 33% say more than 10%. “So there’s a lot of room for improvement,” O’Brien said.

“Part of the energy management problem is that electrical and process automation systems are still separate islands with no unified view,” O’Brien said. “Operators have no ability to manage consumption, and they can’t take advantage of the potential savings.”

IEC 61850, which defines a standards-based infrastructure for power automation asset lifecycle management, offers a path for bringing electrical system information into automation systems, where it can be used to help understand, manage and reduce energy consumption and more.

Standardization brings power under control

IEC 61850 defines  “Communication networks and systems for power utility automation,” said Steve Kunsman, vice president, business development & marketing, Substation Automation, ABB.

 “I’ve seen a lot of automation protocols advance. I have been deeply involved with IEC61850, and while it’s intended as a standard for substation automation, it also brings a great deal of value to the plant.”

Kunsman recommended that we look at the value of using the standard to integrate power with plant automation systems. Edition 2, released in 2013/2014, defines a process-oriented data model that “makes the bits and bytes intelligent,” he said. It defines objects with data models, brings interoperability between objects and engineering tools, and defines Ethernet-based communications, both client-server and peer-to-peer. And it defines a process bus for interconnection to devices.

As we embark on digital automation of electrical systems, “Standardization is providing long-term stability, so a transformer that might last 40-50 years will continue to work with relays that might last 20 years using microprocessors that are updated every year or two,” Kunsman said.

To meet power system requirements, specialized sensors digitize current and voltage signals for the three phases, merge the waveforms and send them to protective devices with time synchronization. Protective systems can trip a breaker in 4 ms.

A typical system architecture is similar to a DCS, with operator interface, station bus, and process bus layers connected using fiberoptic communications to reduce copper wiring, simplify installation and provide immunity to electromagnetic interference (EMI).

Benefits over traditional approaches include consolidation of traditionally separate functionalities, which reduces footprint. Automated monitoring allows early detection of deteriorating equipment, which improves reliability. Safety is enhanced by reducing risks of flashovers and fires, and technicians spend less time in the vicinity of energized equipment.

Can we really integrate process and safety systems?

An integrated process control and safety system (ICSS) offers great potential to improve safety by bringing critical information to the attention of operators, maintenance and management, as well as reduce system cost and complexity. “But can we do this while maintaining the traditional independence of automation and safety?” asked Luis Duran, product marketing manager, safety systems, ABB.

As ABB designed System 800xA High Integrity, critical questions were raised and answered. Do the control boxes really need to be different to avoid common-cause failures? Or can functional independence be achieved with full integration. The answer is in the functional safety standards themselves, and when the standards are performance-based, the answer is yes.

Safety system standards IEC 61511 and ISA84 simply require that basic process control systems (BPCS) and safety instrumented systems (SIS) be functionally independent—that a failure of the BPCS have no effect on the integrity of the SIS. And the standards allow that physical separation may not be necessary.

But there is an increased risk of common-cause failures.

"The integrated platform can reduce this by including a diversity of work processes and assignment structures—through design. But relying on diversity in software does pose management challenges, to maintain an audit trail, to manage change, and to limit access to qualified personnel.”

So all personnel involved with safety systems have to be sufficiently competent, trained on safety and able to follow the functional safety standards.

Key points are to:

  • Design to minimize common causes.
  • Control access with write protection, bypassing and override protection.
  • Perform integrated design, validation and verification tests, including network security.
  • Do version control, compatibility and interoperability testing as part of the release procedure.

Then it becomes possible to take advantage of the relative simplicity of an ICSS to reduce engineering and lifecycle costs, as well as lower training and maintenance costs. Time synchronization is a given, and security can be embedded once, in a single system. Most important, the ICSS may improve safety: Higher visibility may improve your response to abnormal situations, and make you better able to prevent them.

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