Three geothermal electric power generation stations managed using an extensive and distributed iPower SCADA installation covering the generators, the steam-fields and steam pipe network, right through to ancillary applications such as the fire protection system.
"Distributed open client-server architecture is ideal for operating and managing our geothermal power plant installations."
Murray Hill, Generation Engineer - Contact Energy
Murray Hill, Generation Engineer at Contact Energy , discusses their decision to implement Catapult iPower...
"iFIX's distributed open client-server architecture is ideal for operating and managing our geothermal power plant installations, from the steam fields right through to the power station generators. We enhanced iFIX with iPower because of the purpose-built operator dialogs, automated configuration and other useful features like control tagging."
Geothermal Power Stations
Wairakei Geothermal Power Station
Commissioned in November 1958, the this geothermal power plant is situated above a large geothermal system containing water at temperatures up to 240°C. Currently, about 5,000 tonnes per hour of fluid is taken from the reservoir. This is separated into roughly 1,500 tonnes per hour of steam and 3,500 tonnes per hour of water at a temperature of about 130°C. Dry steam is also taken from shallow production wells (up to 500 m depth) and piped directly to the turbines. The steam is directed towards the turbines through the network of pipes around the Wairakei steam field.
Once steam has passed through the turbines it is condensed within 'direct contact' condensers. This cooling system uses water pumped from the adjacent river. After use, the cooling water and steam condensate is discharged back into the river. Gases found in the steam supply are pumped from the condenser and released to the air via gas stacks situated on the power station roof. The hot geothermal water is discharged into a system of drains leading to the river, or it is injected back into the ground.
Ohaaki Geothermal Power Station
Ohaaki geothermal power station was commissioned in 1989. Production wells at Ohaaki are, on average, 1.2 km deep and reach water at temperatures up to 280°C. The most distinctive feature of this station is the 105 meter high cooling tower. Using natural convection, the tower cools the water used to condense the steam as it exits the power turbines. Because little heat or mineralized separated geothermal fluid is discharged to natural waterways, Ohaaki has developed an environmentally friendly reputation.
Poihipi Road Geothermal Power Station
The Poihipi Road power station was commissioned in 1996 and was bought by Contact in January 2000. It is now operated as an integral part of the Wairakei facility and is supplied with steam from the Wairakei geothermal system. Poihipi currently generates around 200,000 megawatt hours (or 200 GWh) per year.
Customer Summary
{csv};
Location;New Zealand
Customers;-
Total I/Os;8,000
Servers;8 servers distributed over three sites
Clients;8 operational clients plus 3 engineering clients distributed over three sites
LAN;Mixed wire, fiber and 100MB microwave LAN
Software;Windows NT/2000, iFIX 2.6, iPower 2.11
Additional Applications;Proficy Historian
Communications & Remotes; Protocols: modbus over ethernet, Dataterm (Catapult developed OPC driver), Abbey
;Media: wire and fiber
;Remotes: ABB PLCs, Abbey RTUs, Dataterm RTUs, Merlin Gerin Powermeters{/csv}
