The Te Rapa power station was commissioned in 1999 and is a co-generation facility providing high quality steam and electricity to Fonterra's Te Rapa factory, one of the world's largest milk powder drying plants.
It was decided to separate certain sub systems from the DCS onto a Safety PLC thus achieving a greater degree of safety for the operators.The dairy season has a small window of opportunity where factories can shutdown and do their yearly preventative maintenance. In our case Fonterra Te Rapa would be shut for 4 weeks meaning that the entire DCS would need to be removed and replaced in one week allowing time to retest every circuit.The heart of any power station is the control system that operates all of the field equipment efficiently and at optimum performance.
At Te Rapa the existing DCS needed upgrading due to age so the decision was made to purchase a new DCS from Singapore. Surplus electricity is directed back to the local grid. Te Rapa power station has a capacity of 44 MW.
Work carried out included:
- Disconnect and remove ABB DCS.
- Install new DCS and re-terminate 3000 I/O points.
- Test loops of all pressure, temperature, level transmitters, Magflow transmitters and motorized valves.
- Documented pre-testing of all cabling and instrumentation.
- Software testing of all actuators and instrumentation.
- Commissioning, calibrating, operator training and as built documentation.