GE Fanuc controls chosen for French power plants

A control concept based on GE Fanuc PLCs and Cimplicity HMI monitoring and control software with in-built redundancy has been successfully implemented in seven French thermal power plants

A control concept based on GE Fanuc PLCs and Cimplicity HMI monitoring and control software with in-built redundancy has been successfully implemented in seven thermal power plants run by ELYO in the Greater Paris area.

The 94,000 MW thermal power plant located in Medon La For?t supplies more than 7,500 households, around 30,000 people, with district heating.

In addition to heating, the plant also generates 7MW of electricity.

Built in 1961, the power plant was coal-fired until two years ago.

Then it was entirely revamped at a cost of 85MF to produce district heating mainly using natural gas, with an annual consumption of 175,000MWh.

The burning of the gas in a turbine generates electricity which is sold by ELYO to Electricit? de France (EDF).

The heat produced reaches four boilers which heat up water to 170C.

Under certain circumstances, the water in the boilers may also be heated by burning oil (annual consumption 400 tonnes).

Reduction of production cost and pollutants Two key demands led to the decision to modernise the plant.

First, there was a need to peg the district heating prices by reducing production costs.

Second, the emission of pollutants had to be reduced to meet stringent environmental demands.

The investment has led to both targets being achieved.

Prior to the modernisation, the power plant employed 24 people, controlling production sequences separately.

Now, the entire production process is fully automated, requiring only five persons for operation and maintenance.

The control concept for the modernised plant was developed and implemented by system integrator SERITHA.

Twelve GE Fanuc Series 90T-30 PLCs are used, with around 1,500 analogue and 1500 digital I/Os.

A particular feature of the control concept is the use of optical fibre.

The PLCs are linked via Ethernet to Cimplicity HMI monitoring and control software running on 2 PCs in a central control station.

An AAUI transceiver is used to connect the Ethernet module on the PLC to the optical fibre, thus ensuring reliable communication between PLC and software.

Christophe Henquinbrant, from system integrator SERITHA, commented: "With GE Fanuc's excellent technical assistance we were able to develop an ideal solution to a control problem which looked difficult at the outset.

This has now been successfully implemented in 6 further ELYO power plants." In order to achieve absolute safety of operation and supervision, a redundant system was implemented at the operator level.

Should one PC fail, the second continues to monitor and control the system.

In daily work however, both computers are used simultaneously.

The Cimplicity HMI software, operating in a Windows NT environment, processes information from more than 3,000 data points.

The PCs are equipped with an SQL Server for database applications.

Data is stored on a daily basis enabling CIMPLICITY HMI to carry out statistical analyses.

Such statistics are used as a basis for peak load management to achieve substantial savings.

The daily need for gas is calculated and set at the beginning of each year.

This value is then used for price negotiations with the gas supplier.

The defined amount of gas is entered into the Cimplicity HMI software feature "Plant Calendar".

The system automatically switches to oil combustion if the daily gas consumption value is reached, since considerable extra costs are incurred if consumption exceeds the negotiated value.

The modernised thermal power plant has been in operation for well over a year.

Lu?c Bochon of ELYO explained, "We were able to increase the plant profitability by 14% after the modernisation.

The control concept along with the monitoring and control software Cimplicity HMI is an essential reason for this good result.

ELYO has decided to convert the two remaining coal-fired power plants in the Greater Paris area as well.".

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