Control system of the power station auxiliary operations for Melnik Power Station

The Melnik Power Station belongs to the CEZ Group. This power station is situated nearby the city of Prague, about 15 kilometers past the junction of the rivers Labe and Vltava. It was built from late 1960s to early 1970s. In the past, the coal was carried from West and North Bohemian coal mines to the power station.

Control system

A brand new control system was installed in auxiliary operations of the Melnik Power Station. Implementation of the control system was split into these parts:

• Black oil station
• Coal handling (part II)
• ZAU propellers
• De-icing tunnels
• Coal handling (part III)
• SCHENCK belt weighs
• EME inner coal handling

The control system is provided by seven Allen-Bradley SLC 5/04 control processors used for the control of the HTO (management of the fuel oils) technological entities. The processors of the EME inner coal handling and ZAU propellers are connected with one another via DH+ communication interface. The DH+ communication interface is redundantly connected into the backbone network via optical line.

The de-icing tunnels are connected to the network via DH485 communicaton interface. The entire control network consist of eight independent PLC devices (Allen-Bradley SLC 5/04).

ZAT-E, the existing control system in the Melnik power station, was availed for the control of the EME III – inner coal handling. The ZAT-E control system is connected via Profibus-FMS device with the SCADA/HMI system as a DDE/OPC device.

A network scanner for DeviceNet is used for data acquisition from SCHENCK belt weighs. This allows acquisition of all data, verification, evaluation of the states and periodically taring the SCHENCK belt weighs from operator workstations.

There are two servers used for data acquisition from RLSLinx OPC, data processing and process control. Both servers also convey the data to one engineering workstation and two operator workstations. On the engineering workstation, the entire visualization can be modified, tested and debugged.

Most workplaces allow remote control. This means that a service engineer can connect to any workplace via telephone modem connection and configure all necessary parameters.

Examples of visualization windows