Very large area SCADA for water supply
Challenges of integration on a grand scale
The challenge facing the IIMAC project is exacerbated by the sheer scope of the enterprise.
The WCWA is one of the largest water utilities in the world, providing water related services
across a state that makes up nearly a third of the Australian continent - an area approximately
the size of the eastern third of continental United States. The WCWA serves a population of
nearly 1.8 million people over 639,000 homes and 48,000 businesses in some 230 cities and
towns. The majority of these towns are "unmanned" (serviced from nearby regional centres).
Some 80% of the population live in and around the capital city, Perth. In an area of 2,525,500
square kilometers, the WCWA operates 243 water treatment plants, 73 dams and reservoirs,
779 water wells in 106 well fields, 107 service reservoirs, 91 wastewater treatment plants,
and 635 water tanks and towers. There are also over 28,000 kilometres of water mains, and
nearly 11,000 kilometres of sewers. Over the last year, the WCWA supplied consumers with
approximately 325,600 Mega-litres of water.
Outside of the capital city of Perth, the WCWA currently uses a variety of technologies to
control and operate assets. Due to geographical constraints each individual scheme is
separate from other systems. Rural systems are most often unmanned and are designed to run
automatically. Individual control solutions have been tailored to meet the particular needs of
each system. Communications with these locations (many extremely remote) is difficult and
expensive. As a result, existing SCADA systems are small and isolated with little or no data
available to central design and investigation personnel, or for operational or regulatory
reporting. They are designed and managed only as a tool for day-to-day operations.
Maintenance is a particular problem due to the remoteness and availability of skilled staff. In
addition, the legacy of a strong regional organizational structure has meant that differing
standards and technologies have been applied around the state.
The WCWA therefore faced the challenge of developing a SCADA architecture that would
meet local control objectives, solve data interconnectivity issues across the state, reduce the
cost of SCADA systems and reduce the amount of maintenance required at remote locations.
This led to the concept of appropriate robust technology at remote locations, a highly reliable
but low cost communications network for SCADA, a modular design and a centralised
SCADA system that would provide a single point for on-line data extraction and supervisory
control of remote systems.
Movement towards a single statewide scada system
As time progressed and experience accumulated in installing standalone SCADA systems,
the concept of installing "regional" SCADA systems evolved. This involved linking all
remote systems in a given region to allow monitoring of all assets from the regional office.
This allowed consolidation of management of operations and maintenance to the regional
level, and automated regional performance reporting. However, it was important that the
control of a remote town's water supply remained at the local level to ensure it operated in
the event of communications failure to the central system. The approach was therefore one of
distributed system control intelligence, but centralized monitoring and supervisory control.
This regional concept developed further into a plan to integrate all SCADA systems across
the state into a single, centrally managed and operated system. This initially was a means by
which the physical SCADA equipment and software could be effectively managed by at a
central location in the capital city of Perth. As there was already a Corporate IT WAN across
the state for business systems users, operator workstations associated with the new SCADA
system could be connected to SCADA servers via that WAN. This effectively would allow
operator access to the SCADA system from any PC on the IT network, and would avoid the
need to establish a second network. This allows flexibility in choosing the location from
which to operate an individual system.
