PipsLinsindustrstrategic petroleum reserves Advanced SCADA computer control techniques being used to improve crude oil transfers Robert E. Stiles, Construction Con-sultant, …

Pips Lins industr

WHAT'S NEW IN SCADATECHNOLOGY

Department of Energy automatesstrategic petroleum reserves

Robert E. Stiles, Construction ConsultantMontgomery, Texas

ceCiCiINS

Reprinted from December, 1987 PIPE LINE INDUSTRY® Magazine

WHAT'S NEW IN SCADA TECHNOLOGY

Department of Energy automatesstrategic petroleum reservesAdvanced SCADAcomputer controltechniques being usedto improve crude oiltransfers

Robert E. Stiles, Construction Con-sultant, Montgomery, Texas

THE U.S. Department of Energy(DOE), is automating the process con-trol system for the major Strategic Pe-troleum Reserves (SPR), located alongthe Gulf Coast of Texas and Louisiana(Fig. 1).

Coggins Systems, Inc., of Atlanta,Ga., has been contracted to provide asystem at the West Hackberry, Big Hill,Bryan Mound and Bayou ChoctawSPR sites. Completion of the four con-trol systems is scheduled for the end of1988. The Big Hill and West Hack-berry systems are already online andare the primary means of control.

Each of these crude oil storage facili-ties is being equipped with a CogginsSystems Series 8100 Distributed Con-trol Sy tem. This system is pro-grammed for automatic operation,while affording ease-of-user interfa ethrough color graphics process displayterminals (operator's terminals).

Under normal operations, a singleoperator is able to manage an entire fa-cility. Complex control operations re-quire only function selection and initia-tion through simple keystrokes with theaid of process display menus.

The SPR torage facilities are undermanagement of The Boeing Petroleum'Services, Inc., based in New Orleans, La.

General configuration. The pri-mary objective of the Distributed Con-trol System (DCS) is to provide eachstorage facility with a simple, but reli-able, means to monitor and control un-derground crude oil storage caverns,pipe lines, pumps, valves and ancillaryequipment (Fig. 2).

Supporting objectives involve inter-facing with field instrumentation toachieve overall site instrumentation

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and control capability and incorporateflexibility for future additions.

The system provides the operator, ata central location, the capabilities to ini-tiate, terminate and channel crude oil,raw water and brine tran fers while si-multaneously observing changes in sta-tus of critical parameters and inventoryrelated information. The system is de-signed for reliability, maintainability,safety and flexibility.

By nature of its design, the DCS usesdistributed intelligence to maximizesystem performance and reliability.This intelligence is programmed intoremote distributed units (RDUs),which are strategically located through-out a facility in close proximity to theequipment and process being moni-tored and controlled.

All control devices and status alarmsare arranged to provide the operatorwith a convenient and logical means ofmaintaining surveillance over the com-plete process. Safeguards are providedto discourage the operator from enter-ing into any operation which could re-sult in damage to equipment or whichcould present conditions that are detri-mental to personnel or the environ-ment.

The operator interact with the ys-tem through simple-to-u e process dis-play terminals. Schematic layouts of theprocess piping and related equipmentare presented to the operator throughcolor graphics displays. These displayare simpl to use, yet offer enough de-tail to permit less experienced personnelto quickly become proficient with thesystem.

Fig. 1-DOE's Strategic Petroleum Re-serves along the Gulf Coast of Texasand Louisiana. The operator's console(inset) is the centralized point of inter-face between operator and DistributedControl System hardware and software.

I Color display copierIOperator's Operator'sterminal terminal

Supervisorycomputer

Pipe lineDRAMSRTU

I RTU Real-time clock1-

00

I Display selectlRTUI annunciator1-

~Data

I Alarm printerhighway I Graphics

I panel

Event printer I System

I terminal

Fig. 2-Distributed Control System simplified block diagram.

Real-time clock Display select!annunciator

Color displaycopier

L---------l--Operator's terminals

OJ :I~ System terminal

Event printer

Fig. 3- Typical Distributed Control System operator's console.

The DCS operator's console. Thisis the centralized point of interface be-tween operator and the DCS hardwareand software. The con olc typically

consists of two operator's terminals, acolor display copier, event and alarmprimers, a system terminal, a real-rimeclock and a display selector/annuncia-

tor. (Fig. 3).Both operator's terminals operate

identically. An operator has only to se-lect a process display from a menu ofdisplays available, causing thc sy tcm todisplay the de ired screen in colorgraphics format.

Operator commands are issued bypositioning the graphics cursor using acontrol level (joystick) or special keyson the respective operator's terminal,then pressing one or two function kcyswhich are uniquely designed to executethe intended operation.

Supervisory computer system.This is the heart of each DCS. It con-sist of a Hewlett- Packard HP 1000computer system executing Hewlett-Packard' RTE-A Real-Time ExecutiveOperating System oft ware under thecontrol of Coggins Systems' Series 8100

oftware.One of two supervi ory computer

system (SCS), configurations is used:• Redundant supervisory computers

for symmetrical failover or• A single supervisory computer in-

terfaced to a master control unit basedupon Allen-Bradley's PLC-3 Program-mable Controllers. Both configurationsare designed for maximum systemavailability and overall reliability.

Color display copier. This use ink-jet technology to reproduce any opera-tor's terminal display screen onto a spe-cial clay-baked paper to allow the ink todry instantly. A terminal-to-copier se-lector switch permits connection to ei-ther Operator's Terminal for copying ofany process or data display.

Event printer. This printer logs all sitereports, operator commands and sys-tem events.

Alarm printer. All alarm informationdetected by the system, including time,date, process name, description, varia-ble name, current status and operatorresponse is printed.

Real·time clock. An extremely accu-rate system time standard which en-sures that all internal software locks ofthe distributed control ystem are auto-matically synchronized at power-onand at predefined intervals.

Display selector/annunciator.This permits the operator to display aprocess display screen quickly. A sepa-rate backlighted pushbutton on the dis-play selector/annunciator is providedfor each display screen. The display se-lector/annunciator can be enabled to ei-ther of the two operator's terminals or

disabled by pressing the appropriatelylabeled pushbuttons.

System terminal. A monochromedisplay terminal is used as a backu pmeans of operator interface or as a pro-gramming terminal. It is also used asthe main site management data entrydevice for making data available to the

ew Orleans Data Reporting andManagement System (DRAMS).

Graphics panel. A free-standingmimic gmphic display unit provides asimplified pictorial representation ofthe ite process. This panel shows thestatus of pumps and motor-operatedvalves and various alarm conditions.The color coding and light statuses forthe pumps and valves are the same asthe Operator's Terminal screen dis-play.

Audible alarm system. This emitsone of three tones based on the priorityof an alarm, signalling the operator ofthe urgency of action required.

Data reporting and managementsystem link. This provides data andstatus information to the DOE centralDRAMS center in ew Orleans.

Pipe line terminal link. Communi-cations between the site and its conne t-ing pipe line terminal's RTU for moni-

Copyright<' 1987 by Gulf Publishing Company. All rights reserved.

toring of crude oil transfers is providedby this link.

Redundant data highway system.This system provides redundant com-munication links between the RDUsand the supervisory computer/mastercontrol unit. If the primary data high-way fails, communications are auto-matically transferred to the econdarydata highway to ensure uninterruptedcommunication.

The RDUs are stand-alone ontrolsystems strategically located throughouta site and are interfaced to field instru-mentation and controls. Since eachRDU is a stand-alone unit, the loss ofcommunications with the control roomsignals the respective RDU to operatein a predefined mode of operation, con-tinuing to execute its RDU programand process associated input/outputfunctions.

DATA REPORTING ANDMANAGEMENT SYSTEM

To aid the DOE in its overall man-agement of the SPR, Coggins Systemsis providing the hardware, software andinstallation of a DRAMS. DRAMS isan information system permitting re-mote monitoring from New Orleans ofSPR sites equipped with a Coggins Sys-tems Series 8100 DCS. Two main func-

tions performed by the DRAMS are:• Real-time process display with

video hardcopy.• Automatic collection of data and

reports.

Real-time process is visually dis-played in New Orleans by color graph-ics process display terminals. Withthese terminals, the user has direct ac-cess to any site's data base permittingimm diate display of process informa-tion in color graphics schematic or dataformats, identical to those which arepresented to site operations personnel.Color video copiers p rmit hardcopy re-production of any site's real-rime dis-plays or data displays.

Automated collection of data and re-ports is performed by the DRAMS au-tomated computer system which in-t ractively communicate with each ofthe individual site. This system for-mats the acquired information intosummary reports for storing and print-ing. Dynamic, periodic and on-demandreporting of process operations and sitemanagement data are available to theuser for printing on either conventionalor laser printers. The report data arealso formatted for personal computercompatibility to support management'suse of DRAMS information with otherstandard software products. _

Printed in United StoreF/2M/188