July/August 2010

Cover Story

Automating one of North America's largest pipelines

Standardized SCADA controls and software reduce engineering and commissioning time keeping 1,700-mile pipeline on schedule

Fast Forward

  • Common development tools helped streamline natural gas compressor unit control system design and configuration.
  • Reusing software libraries helped River Consulting accelerate code development and reduce commissioning time. 
  • Common distributed I/O platform on compressor units and compressor stations simplified design, reduced spare parts and simplified training.
 
By Steve Pulsifer and Jim Nelson

Managing the construction and installation of one of North America's largest pipeline projects is not an easy job. In fact, a project of this magnitude requires a significant planning and organizational effort. It is very important automation system suppliers and engineering partners provide necessary equipment and control technology support with maximum speed, accuracy, and efficiency.

auto 11With more than 37,000 miles of pipeline and 170 terminals, Kinder Morgan is one of the largest pipeline transportation and energy storage companies in North America. The company transports, stores, and handles energy products like natural gas, refined petroleum products, crude oil, ethanol, coal, and carbon dioxide-all products essential for generating electricity, heating homes, and powering cars.

Kinder Morgan also is the joint developer and project manager of the Rockies Express Pipeline, a natural gas pipeline spanning 1,678 miles from Western Colorado to Eastern Ohio. The pipeline has a carrying capacity of 1.8 billion cubic feet per day and includes multiple interconnects with other major pipeline systems to provide U.S. consumers with a natural gas supply with excellent reliability. 

Challenge

A critical project task for the Rockies Express Pipeline was designing and constructing 13 compressor stations that were built as part of the pipeline route. The stations house individual compressor units that help regulate and boost the pressure in the pipeline to keep the gas moving to its destination. Each station includes two to five compressor units, depending on the specific requirements along the various pipeline segments.

Because of the critical role the compressors play in the pipeline's operation, Kinder Morgan wanted the units equipped with control and monitoring technology that was easy to operate, maintain, and support.

Equally critical was the need to meet the project's tight timeframe and complex performance and operational demands.

To handle this task, Kinder Morgan selected River Consulting as a system integrator based on their oil and gas industry experience. The system integrator's core responsibilities included configuring the controls and monitoring for each of the compressor units as well as installation, startup, and training of station operators.

With a need for high reliability and design consistency from station to station, the system integrator required a  standard control platform that would allow for fast configuration and troubleshooting while being simple to operate and maintain. Meeting project timelines and milestones also was critical since the construction schedule relied on a closely coordinated effort.

"We needed a technology platform that could not only handle the complex processing demands, but provide the consistency and standardization we needed to get the software configured and installed quickly, efficiently, and cost effectively," said Ed Grabowski, electrical project engineer at River Consulting. "We also wanted to make sure the chosen control system vendor could back up the equipment with support and technical assistance whenever we needed it."

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The Kinder Morgan Rockies Express Pipeline is one of the largest natural gas pipelines ever constructed in North America.

Solutions

River Consulting selected a system that combines process, discrete, and supervisory control and data acquisition (SCADA) information on a common software architecture using programmable automation controllers (PAC). The system communicates using EtherNet/IP network protocol.

The system manages overall control functions of the compressor units, including loading and unloading, safety monitoring, alarming and diagnostics, as well as data logging and trending of critical run-time data. Each controller is configured to perform a variety of advanced processing tasks, as well as complex monitoring, extensive alarming, and tightly sequenced startup and shutdown processes-all of which required considerable engineering effort. The engineering was done more efficiently by using a common library of code for applications that could be replicated from unit to unit in a straightforward manner.

The compressor unit PAC monitors and controls a variety of functions, including safe operation, load, speed, efficiency, emissions, and throughput. Run-time information is transmitted via a fiber-optic network to a site-level "Station" PAC located at each compressor station. The station PAC serves as a supervisory controller that communicates with each compressor unit to take on or off-line depending on pipeline conditions. The station PAC is linked to a central control center via a SCADA network. At the control center, operators monitor the status of all the compressor stations and individual compressor units along the entire pipeline system.

River Consulting standardized all of the I/O on the compressor units and compressor stations using modular Flex I/O that communicates with the unit PAC over an Ethernet connection. Standardizing the design helped reduce the quantity and types of spare parts needed at each compressor station site.

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The Rockwell Automation PlantPAx Process Automation System manages overall control functions of the compressor units. At the heart of the PlantPAx system is an Allen-Bradley ControlLogix PAC, which provides scalable, multi-disciplined control, and information capabilities.

Results

With the pipeline complete, Kinder Morgan has already documented quite a few initial successes.

Kinder Morgan selected a single control system architecture from one vendor to ensure consistency in design and familiarity to reduce the learning curve and training for staff working on the equipment and allow them to get up to speed quickly. "… The consistency of the controls from one station to the next makes their jobs even easier," said Brent Hansen, automation manager at Kinder Morgan. "No matter which compressor unit they are working on, the technology is the same."

The built-in instruction set in the programming software saved considerable engineering time. By having access to common control algorithms, engineers reused instructions multiple times, helping improve consistency between units and saving engineering labor.

With the ability to standardize the application logic, River Consulting only had to perform in-house testing on one basic design, helping reduce engineering time and costs. Rockwell Software's cut/copy/paste capabilities were also extremely valuable in allowing engineers to develop and import standardized libraries of logic into the software. Individual compressor unit PAC software address comments, tag names, and rung comments that were exported and edited in MSExcel and then re-imported into the program. This approach helps ensure a consistent look and feel of the software throughout, and it was accomplished with the efficiency of typical spreadsheet editing tools.

"The ability to export and manipulate facets of the software using spreadsheets, and search and replace features, greatly improved our efficiency and reduced development time. The Kinder Morgan commissioning goal for each compressor station was three weeks. These time-saving tools greatly improved our ability to consistently meet startup schedules, which we did in all of the project sites," Grabowski said.

Alarm and shutdown functions are part of the PAC programs for each compressor unit. The programs are written in a manner that allows the operator with the proper clearance to configure the specific action taken on every alarm, from annunciation only to orderly shutdown, fast shutdown, or depressurization. The ability to configure action taken during upset conditions with this configurability gives operators and maintenance personnel an additional tool in isolating and identifying issues with compressor unit equipment.

This makes the on-site effort to maintain the alarm system much simpler. Changes made to alarms are only made in one place, the unit HMI. The changes are communicated to the PAC. This eliminates the need for on-site personnel to modify PAC software and reduces the potential for mistakes.

"The alarming system was easy to set up and configure with the programming software," said Grabowski. "It helped us put together a body of code that is easily configurable while delivering crucial monitoring and control functionality for the end user."

Many of the compressor stations and supporting equipment for the Rockies Express Pipeline operate virtually unmanned around the clock, year-round. Therefore, high reliability and easy troubleshooting were key requirements.

"The compressor stations are a crucial part of our business, so the equipment and software we are running at these sites is extremely important to us," said Hansen. "We would not be able to make a profit if we didn't have technology in place to help operate these stations safely and efficiently."

Kinder Morgan employed this same control platform in its recently completed Midcontinent Express Pipeline project and expects to rely on it again in future projects. "We will build on and reuse many of the applications we have developed, which will help further reduce engineering costs and maximize our resources," Hansen said.

ABOUT THE AUTHORS

Jim Nelson is director, Technical Services at River Consulting. Nelson has more than 17 years of experience in electrical and control system development. Steve Pulsifer (sepulsifer@ra.rockwell.com) is global director of Process Marketing Development for Rockwell Automation. Pulsifer joined Rockwell Automation in 2007 and is currently responsible for all Commercial programs as they relate to the Process business.

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