Visualization and control of the gas distribution pipeline system for South Bohemia

E.ON Czech Republic, a joint stock company, is a distributor of natural gas in South Bohemia. The object of the company is to maintain the reliability of the gas distribution system in the region and secure the continuous supply of natural gas to its customers. The main shareholders of the company are Oberösterreichische Ferngas AG Linz and E.ON Czech Holding AG München.

The company decided to innovate its main control system in 1999. After thorough evaluation of several SCADA systems, the company chose the Reliance SCADA/HMI system. The aim of the new system was to visualize all interchange super high-pressure and high-pressure regulation stations.

The approach of the company has been very active since the beginning. Employees at the gas distribution company wanted to create and maintain the visualization by themselves, so after creating the basic project for several first regulation stations, technicians were well trained to be able to maintain and expand the system by themselves.

Several hundreds of gas pressure regulation stations have been modernized and connected to the system since 1999. In 2005, the conversion was completed. The system now consists of more than 300 gas pressure regulation stations connected to the main control room via GPRS, radio modems, and modems 24 hours a day.

The control system meets these requirements

• Data acquisition from all connected gas pressure regulation stations
• Communication with regulation stations using GPRS, modems, and radio modems
• Automatic handling of incoming calls
• Generating, logging, and distributing alarms/events
• Archiving all historical data
• Setting up setpoints and alarm limits
• Sending commands to regulation stations
• Exchanging data over a LAN/WAN using TCP/IP
• Statistical evaluation of the historical data
• Web access to the system for responsible people within the company
• Exporting data to the Corporate Central Data Storage system (ORACLE)
• Exchanging data with the Customer Information System
• Exchanging data with the Gas Consumption Prediction System

A gas regulation station

System structure

• Data communication PC
• Main control room PC
• Data storage plus WWW server
• Web clients

Structure of the control system

Data communication PC

This computer communicates data from the regulation stations using GPRS, modems, and radio modems. There is a special multiport card in the computer. Data is distributed over the network to the main control room PC and data storage + WWW server via TCP/IP.

Main control room PC

The main control system computer is equipped with two LCD displays for an enhanced overview of the system and alarms. Incoming data and alarms are synchronized among all computers in the system. The control room manager can send commands to any gas regulation station via the data communication PC.

Main control room

Data storage plus WWW server

This server stores data received from the system to the ORACLE database. It acts also as a Web server for Web clients that can access process data from the company's intranet. Another important task of this server is to export data from the control system to the company's customer information system and gas consumption prediction system. Selected data is also automatically transferred to the national central gas control room in Prague via FTP.

A map of the gas distribution pipeline system

Gas regulation stations are assigned to the following service regions

• Ceske Budejovice
• Tabor
• Prachatice
• Pelhrimov
• Strakonice
• Cesky Krumlov
• Pisek
• Jindrichuv Hradec

Examples of visualization windows

Overview windows display the key values from the system including information about alarms. Data is communicated periodically, but if the control room manager needs to get the fresh data instantly, he can get it by clicking the yellow "Call" button in the system.

The control room manager can go anytime from the overview screen to the detailed process scheme of a regulation station.

In the detailed process scheme, displays with values are located in the position where the value sensor is installed. Values of pressure, temperature, and gas volume are monitored. Key information is the status of gas secure flaps. If necessary, the control room manager can establish on-line communication with the regulation station and observe it "live" to see if something happens in the station.

All the values stored in the archive can be presented either in trends or tables. There are hi and lo limits displayed together with the value. Responsible people can go through the history and make data analysis (for example, compare the trend of the value with the same time period of previous years). Data is exported to the Central Data Storage System of the company. The ORACLE database is used as the main database system.

Data stored in the archive can be presented in various kinds of statistical reports (hourly, daily, monthly). Statistical items as a minimum, maximum, average, or sum of the selected value is displayed in the report, too. Reports can also be printed out.