This project has been accomplished as a part of another project that envisaged the modernization of outdated steam power plant TEC-1 in Riga, Latvia, aiming at the building of a new plant and a gradual decommissioning of the old one. The new complex would consist of a cogeneration plant including also two power turbines, one steam turbine and two water boilers with a capacity of 116 MW per each with added network pumps.
The goal of this project was a complete automation of water boilers and their service equipment; a creation of local control and organization of data exchange with a control system of the cogeneration plant in order to provide a remote control opportunity.
The equipment of the Boiler House consists of two water boilers KVGM-100 with four combined burners (gas, oil fuel), also a water cycling system and supporting facilities.
As the goal of this project was an automation of large heat-supply system, there were high reliability and fault tolerance requirements set for this assignment as the object of automation was the second biggest by its capacity in Riga. A special attention was also paid to the operational safety issues as potentially dangerous substances have been used for a boilers operation.
In order to provide a high reliability and unification of the automated equipment of power part of the plant, a decision was taken to use controllers ABB AC 160 and graphic panels Telemecanique Magelis XBT GT 6000-Series as a local control system. A connection to the control system of cogenerated facility based on controllers ABB AC 450 and the visualisation system ABB Advant Station 500 was organized through busbar AF-100.
Control system consists of three main parts:
Boiler No 1
Boiler No 2
Common Equipment
A separate controller is responsible for each mentioned part. All controllers are linked throuhg the busbar AF-100 which provides the data exchange process.
Automation of burning process is implemented separately for each burner of the boiler by an independent scheme with using components manufactured by DURAG Group (Germany).
Burners of the boilers are controlled by pairs, as boilers can function either in the constant power mode or constant temperature one. The system can control the water consumption delivered into the network or the pressure of the power conduit independently of boilers operation mode.
According to the test results the following parameters of the boilers system operation were drawn out:
Heat load range: 11.6-232 MW (stepless)
Water output temperature: 60 – 150 C
Water consumption via Boiler house: 50 – 6000 m3/h
Atmosphere pollution: NOx < 150 mg/m3
CO < 100 mg/ m3