Bolivia-Brazil Pipeline SCADA Provides Advanced Remote Management Capabilities.
The pipeline gathers gas from the Rio Grande area in Bolivia and ultimately dispatches it 3,150 km away in Canoas, Brazil. The pipeline crosses the Brazilian states of Mato Grosso do Sul, Sao Paulo, Parana, Santa Catarina and Rio Grande do Sul; and connects with the existing gas transportation facilities in Sao Paulo state. The pipeline has a diameter ranging from 32 to 16 inches. It is designed to reach a gas outflow of 30 million cubic meters per day when operating with maximum capacity.
The BBP and related gas transportation facilities have been built by Petrobras under a turnkey contract with GTB (Gas TransBoliviano) and a Construction Management Agreement with TBG (Transportadora Brasileira Gasoduto Bolivia-Brasil S.A.). The Bolivian side was put in operation by Petrobras and the Brazilian side by TBG. TBG in Brazil and GTB in Bolivia are the owners of the pipeline in their respective countries.
When fully completed, the BBP will incorporate:
* sixteen compression stations;
* three billing measurement stations located in the trunklines;
* seven operational measurement stations for pig launchers/receivers facilities located along the pipeline; and
* thirty-eight pressure measurement and reduction stations to supply the various gas distributors.
SCADA System Architecture
Petrobras has engaged a single vendor, The Foxboro Company of Foxboro, MA to implement an integrated SCADA, (Supervisory Control and Data Acquisition) system for the entire pipeline. The project was managed by the Rome, Italy-based Foxboro SCADA group, which serves as a global center of excellence for SCADA solutions for the oil and gas, water and wastewater industries/ Foxboro's scope of supply includes SCADA control centers, local/remote station controllers, flow-computers, telecom interfaces, power supply and UPS subsystems; plus project management, installation, implementation, and training services; and all SCADA application software.
BBP's fully distributed SCADA system architecture encompasses:
* two main supervision and control centers, one at Rio de Janeiro in Brazil and the other at Santa Cruz de la Sierra in Bolivia. These facilitate remote centralized management of the two pipeline portions;
* eight local supervision and control centers managing five major gas compressor stations (four in Brazil, one in Bolivia) and three regional maintenance centers (in Brazil);
* forty-three remote stations, PLC-based, for local automatic plant control and remote data transmission along the line, in the trunk line billing measurement stations, in the city gate facilities;
* data transmission through three integrated communication technologies: VSAT INMARSAT Satellite links, public dialed telephone lines;
* leak detection modeling and application software;
* flow computers and sensors; and
* solar photovoltaic power panels and UPS systems. These power wireless PLCs, instrumentation and telecom along the pipeline.
Main Supervision & Control Centers
The two Main Supervision and Control Centers (CSC), one located in Brazil and the other in Bolivia, receive and process - in real-time/data for all of BBP's facilities, including all facilities required for system operation, follow-up, configuration and maintenance. These CSCs are designed to manage up to 40,000 points.
The Brazilian Main CSC, Windows NT based, is equipped with:
* a redundant I/O and TAG server with printer;
* four operator stations;
* an industrial SQL Server for real-time and historical database;
* an engineering and configuration station;
* an "advanced functions" (application software) station;
* two auxiliary computers;
* two printer servers with printers;
* two routers with dual LAN connection;
* VSAT and INMARSAT satellite interfaces and PTT-dialed telephone line interfaces; and
* GPS interface to synchronize SCADA clocks.
A similar architecture is present in the Bolivian CSC where the equipped SCADA nodes are now UNIX-based.
Local Supervision & Control Stations
Local Supervision and Control Stations (ELOS) are located in each of the main compressor stations. The ELOS exchange data with the CSC and facilitate local management of the stations and all related facilities.
The ELOS interface directly to the field through a redundant local connection with Allen-Bradley and GE-Fanuc PLCs (LAN Ethernet with TPC/IP protocol) with PC-based powerful Human Machine Interface (HMI) tailored for local operators. Each ELOS is equipped with:
* a redundant I/O TAG server and operator's place with printer;
* two auxiliary computers;
* two printer servers with printers;
* two routers with dual LAN connection;
* dual LAN connections toward the Allen-Bradley PLCs managing the compressor station; and
* VSAT and PTT dialed telephone lines interfaces.
A redundant Ethernet LAN connects all the SCADA nodes, while a GPS interface synchronizes the local system clocks.
Regional Maintenance Centers
Regional maintenance centers (EMAN) are interfaced to the main CSCs and receive all data required for maintenance operations within their region. Each EMAN is equipped with an operator station used by the technical teams responsible for the pipeline's facilities maintenance in their related geographical area.
Forty-three remote stations presently installed, are located along the length of the pipeline. These include "EMED" remote stations for trunkline billing and measurement, "EMOP" stations for operations support, and "city gate" remote stations to support gas measurement and supply to local distributors.
Appropriate data acquisition, control and communications functionality at the remote stations are performed by GE Fanuc PLCs.
EMED Remote Stations
The three EMED remote stations are responsible for data acquisition and control of trunkline billing measurement facilities. These are located at the beginning of the pipeline in Bolivia, on the border between Bolivia and Brazil (at the Bolivian side, sending data to Brazil and Bolivia), and at the end of the pipeline's northern trunk in Brazil.
Fiscal gas calculations (AGA-3 and AGA-7) are performed by redundant flow computers and transferred to PEgs. Gas composition parameters can be updated in real-time through local gas chromatograph analyzers (where available) or downloaded from the control center by means of a dedicated operator's function.
EMOP Remote Stations
EMOP remote stations acknowledge data and supervise the operation measurement facilities, including scraper launching/receiving installations. The same PLCs perform remote data acquisition functionality and are used to manage the scraper trap sequence locally.
City Gate Remote Stations
These remote stations handle data acquisition and control of pressure measurement and reduction at the city gate plants that supply gas to local distributors. AGA-7 gas calculations are executed by PLCs. Gas composition parameters are downloaded from the control center by means of a dedicated function on operator's demand.
An advanced hybrid communication system has been designed to guarantee safe and reliable transfer of information between the main control centers and the SCADA nodes distributed along the pipeline. VSAT and INMARSAT satellite links provide the primary transmission media. The VSAT channels are permanent satellite connections for high-speed data transmission between control centers (utilizing TCP/IP protocol) and from CSC to EMED PLCs (utilizing CCM protocol). INMARSAT lines, connecting CSC with all PEgs, are activated only when PLCs data transmission and time synchronization is required.
A public dialed telephone line is available to back up each satellite link in all control centers and EMED remote stations. PTT line switchover is automatic upon VSAT channel failure. Each VSAT line is scanned every five minutes to ensure proper operation.
All PLCs communicate with the CSC using peer-to-peer CCM protocol and the "unsolicited transmission by exception" technique. A background polling cycle scans all inputs in each PLC at programmable intervals to avoid data misalignment.
PLC local clocks receive time synchronization commands from the CSC through INMARSAT dedicated channels or VSAT data channels (on EMED only). Detailed dedicated diagnostic displays on CSC operator stations show the status of each communication media and channel in real time.
Pentium III-based personal computers are utilized in the SCADA nodes located in the Brazilian control centers, while the Bolivian SCADA center is equipped with Compaq/DEC AlphaStation machines. This hardware provides an open, high-performance platform for human machine interface (HMI), database and communications management.
Extensive redundancy of all hardware, database archives, and LANs ensure high overall system availability. GPS interfaces are equipped for local system time synchronization in CSC and ELOS centers.
The remote PLCs manage advanced local calculations (AGA) and automatic sequences. The PLCs are configured to perform full remote I/O management functionality with CCM Peer-to-Peer data transmission to CSC on spontaneous intervention at every significant field input data variation.
Each remote station is powered by photovoltaic solar panel, with battery backup for both the PLCs and all plant instrumentation and communication interfaces.
In the Brazilian SCADA portion, the PC-based software applications were created using Wonderware's powerful FactorySuite 2000 as a development platform. This provided an open, client-server software architecture; excellent connectivity and scalability; a fully integrated Windows NT environment with 32-bit object-oriented Graphical User Interface (GUI); Industrial SQL Server real-time relational database (supporting both SQL and ODBC standards); plus distributed alarm, historical, and commands subsystems. TBG has participated, with its automation team, in the development and customization of some portions of the SCADA software during the migration from the original UNIX-based environment to the Windows NT Wonderware platform.
A different software environment is equipped in the Bolivian portion where the SCADA center is managed by a UNIX system.
SCADA system applications include:
* remote supervision of all pipeline facilities;
* valves, plant devices, scraper control and status;
* compressor station remote supervision and control;
* fiscal measurement of gas transported and delivered to distributors
* real-time interface to application software models and calculations (leak detection and location, gas line pack calculation, etc.);
* local and remote data acquisition, synchronization and validation management;
* set points and PLC control sequences management;
* advanced HMI (graphical displays, trends, printouts, reports, logs, etc.)
* alarms, events, logs, reports, graphic displays, database access (generation and maintenance);
* storage, retrieval, and backup of historical data; and
* real-time system components status displays and automatic control switchover handling upon faults.
Specialized application software is integrated into the SCADA system and HMI to provide the following additional functionality:
* leak detection and location;
* pig tracking; and
* gas line pack calculation.
Real-time dynamic pipeline models are used for detecting a leak and its corresponding location as well as for pig tracking and parameter tuning. The governing equations for the pipeline models are conservation of mass, momentum and energy, equation of state for the fluid. Models that calculate the thermodynamic properties of the transported product and its dynamic temperature are included. Boundary conditions for each of the pipeline sections are used to determine real-time profiles of product's pressure, flow, temperature and density along the pipeline accounting for variations due to the operation.
The pig-management software tracks the position of the scraper in the pipeline, calculates time of arrival to the next trap, and warns the operator at the receiver station where the pig is approaching. Scraper position updating is based on the velocity profile generated by the flow model, with automatic leak detection threshold tuning to avoid false leak-alarms during the pig transit in each pipeline section.
The gas line pack calculation determines the quantity of compressed gas actually contained in each pipeline trunk/section. It can also be used for gas inventory for those specific operating conditions where the pipeline itself serves as a reservoir for gas storage.
To enhance safety, the leak detection application software provides SCADA operators with timely information on suspected leaks, calculated leak size, and likely location(s).
By utilizing a single vendor approach, all SCADA software, hardware and communications, have been successfully integrated into a common, bi-national spread, supervisory and control system structured to enhance the operational efficiency of this extensive gas pipeline, while reducing training requirements and ongoing engineering support costs.
The author wishes to thank TBG in Brazil, GTB and TransRedes in Bolivia for permission to refer to the Bolivia-Brazil pipeline project in this article.
Massimo Bianchini is the marketing manager of Foxboro SCADA SpA in Rome. He has worked in the industrial automation and SCADA field since 1975 in positions ranging from technical manager, projects manager, to sales and accounts manager. He previously worked for Nuovo Pignone--Automation Systems Division and General Electric Co. He can be contacted at: firstname.lastname@example.org / email@example.com
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|Comment:||Bolivia-Brazil Pipeline SCADA Provides Advanced Remote Management Capabilities.|
|Publication:||Pipeline & Gas Journal|
|Date:||Aug 1, 2001|
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