This system controls and monitors the entire combined cycle plant.
A distributed control system based on a microprocessor has been set up at the plant and comprises different communications systems that control and oversee all the plant´s systems and subsystems. This communication system is connected directly to the instruments and to the control buses in order to link up the systems in the “control islands”.
The system features all the elements required to enable man and machine to link-up in unison so that all the actions involved in the operating, management and integrated maintenance of the entire plant can be conducted.
All the control systems are interconnected within a redundant main network which is in turn connected to the control and monitoring station and the engineering station. Gateways are used to link the main network to secondary networks which are themselves linked to management, operating and remote control stations.
In view of the stringent and specific demands in monitoring the regulation of the gas and steam turbine-generators it is vital that specially designed, independent, autonomous systems are incorporated to provide this service. Complete transparency in the control, monitoring and setting of parameters in relation to these control systems is needed to safeguard the philosophy of distributed control, however, as the operating and monitoring stations are the means of overseeing and controlling them.
In accordance with the plant layout a series of subsystems has been created, mainly the packaged plants and the electrical system, which have their own independent control system as they operate autonomously. As a result, this main control system generates a secondary control network from which the subsystems branch off:
As with the turbine-generators, the main control and monitoring functions of these subsystems are performed from the main control centre, thereby safeguarding the philosophy of distributed control.
Emergency shutdown system
In response to the legislation currently in force an emergency shutdown system – entirely independent of the control system – is set up in BEE.
This system ensures the plant is shut down safely.
It includes all the elements required to issue shutdown commands rapidly and is equipped with a system blocking any involuntary shutdown commands.
The system can also send out these commands from the area around the requisite equipment and from the control room.