Visualization and control of gas pressure regulating and pipeline cathodic protection stations in Prague

Prazska plynarenska is one of the largest gas suppliers in Czechia. The company provides natural gas supply to both residential and commercial customers headquartered in Prague and its suburbs. In addition, it provides natural gas supply to Kladno. As a result, the total number of customers to whom gas is supplied by the company is nearly half a million.

Control system

In 2004, the GEOVAP company implemented a system designed to monitor the medium-pressure regulating station network and the gas pipeline cathodic protection station network in the capital city of Prague. The main investor was Prazska plynarenska. Over time, the system was expanded to monitor the electrical polarized drainage stations. The number of connected stations has been increasing steadily over the years and has reached about 180 regulating stations, 50 cathodic protection stations, and 10 electrical polarized drainage stations. Cathodic protection and electrical polarized drainage are techniques used to control the corrosion of gas pipelines. They are mainly used in cities with streetcar systems where stray currents accelerate the corrosion.

A gas regulation station

Data acquisition is provided by GPRS. Individual stations themselves regularly log on to the network and pass the measured data to the central server. In rare circumstances, a connection can also be established when an alarm is detected. In this way, the minimum electric power consumption of a GSM modem is provided. This is very important because most of the stations are powered by storage batteries or solar panels. To visualize the stations' processes, the Reliance SCADA/HMI system is used. Data connection between Reliance's runtime software and the devices is provided by IEC 60870-5-104 Communication Driver.

The monitoring and control system provides

• Data capture from the regulating stations
• Data capture from the cathodic protection stations
• Data capture from the electrical polarized drainage stations
• Communication with the stations via GPRS and a GSM modem
• Automatic receipt of alarm callbacks
• Evaluation, logging, and distribution of alarms
• Archiving and distribution of historical data
• Network communication between individual computers via the TCP/IP protocol
• Data distribution to Web clients

Examples of visualization windows