(Real Time Water Resource Allocation Planning)
For Yorkshire Water Services Limited
Project Value £1,500,000
‘WRAP’ (Water Resource Allocation Planning) is an existing process that provides the strategy for production/distribution of water for a major utility company.
Plant availability, works output capacity, demand, reservoir levels, etc. are examined in order to provide operational data for the entire network. The plan is delivered to the network managers once a week, who have the appropriate meetings with staff to arrange site visits to operate network assets (valves, operate water pumping stations, water treatment works etc.) to direct water to where it’s required. The whole process is performed upon a weekly basis. After implementation, the network requires constant adjustment because plant fails and demand can never be predicted, therefore continual round-clock site visits occur. REAL-TIME WRAP (rtWRAP) does all this automatically, fast (approximately 1 hour for ‘plan delivery’), as frequent as required, no site visits and no manual intervention on plant failure. How is this possible?
Key network distribution assets (valves, reservoirs, pumping stations, water treatment works etc.) are identified. If they are manually operated sites, a PLC is installed and they are automated. All of these assets are engineered to control throughput to a single flow set point. All assets are placed on a Wide Area Network with dual redundant communications connections (i.e. ADSL and GPRS) and are controlled by a master PLC known as a WAC (Wide Area Controller). Each asset provides operational data such as plant availability and flow capability to a WAC.
A number of WACs are utilised to control the whole service area. Typically, the control area of one WAC is 300 sq. miles. A WAC monitors all of it’s ‘tanks’ (reservoirs, WTW clear water tanks, etc) for rising/falling levels against a diurnal profile and calculates surplus/deficit volume and rate of change as it occurs. Surplus water in one tank is utilised to replenish deficit water in another tank, and vice versa. ‘Flow Routes’ are utilised by a WAC to move this water between any two points on the network.
As plant availability changes (pumps trip, valves jam, interlocks prevent operation, etc.), tank levels are affected and a WAC re-routes water accordingly, only using the available distribution capacities of plant. Sites can be manually inhibited so that routes where they are required cannot be used – this enables a WAC to operate around identified burst mains or target the supply of better quality water to their Customers. If there is a general deficit of water in the area, more can be produced by water treatment works, if there is a general surplus of water, less can be produced. System controllers can spend time focussing on real issues whilst a WAC provides the day-to-day operation of the network.
A simulation system provided emulation of ALL assets as well as varying network demand for a WAC’s network to test the capability and routing configuration. A simple procedure allows a WAC to disconnect from a simulated environment and communicate with the real assets to control the real world.
A SCADA system is utilised to advise a WAC of valid ‘flow routes’ (using the identified network assets) around the network. A WAC programme is engineered to be generic so that these routes can be easily adjusted, instantly – every possible permutation of routes could be implemented.
The SCADA system also details the entire network status real-time, as opposed to traditional telemetry systems where status can only be ascertained after manually connecting to a an asset.
This SCADA system is available through a Citrix Server – anyone can view it, anywhere there is an internet connection – from an office at the End Users main offices to a site operative using wireless networks in the field.
The project was operated under a ‘development scheme’ basis – the programmers implemented the solution in a manner as they saw fit instead of to a prerequisite control philosophy. This working environment produced an innovative and flexible solution that can cater for all the distribution requirements of the entire water supply zone. The generic WAC/SCADA system code was the product of 10 months development. Once this template existed, further WAC, SCADA and combined Simulation systems can be produced in a matter of weeks.
The system covers approximately 80 PLCs, local telemetry and over 20 SCADA systems (including the main regional centre).
Money is saved by reducing site visits and manual intervention. It’s saved by prioritising flow routes to be utilised in order of expense – routes using gravity (valves) are utilised in preference to routes that require pumping. Money is saved by reducing already operating pumping stations and increasing gravitation where possible. Money is saved by increasing production via water treatment works outputs as a last resort. Money is saved by increasing production in an order of efficiency – better water treatment works are increased before the more costly ones. All of this prioritising can be instantly re-ordered and saved into entire ‘libraries’ for different conditions – i.e. drought, wet day followed by dry day, winter conditions, etc. The savings are estimated at a five figure sum per week.
The overall project took 24 months to complete.
A very detailed (every activity identified) programme of works was developed by the Team and monitored on line. Meetings are held in a central location to co-ordinate activities on a weekly basis. All team members are encouraged to work from the office for 1 day per week to ensure that the works are progressing correctly and no problems are being encountered (as this could have a knock on consequence). At the peak there were 7 Blackburn Starling Engineers plus 5 Engineers from the Yorkshire Water working on the scheme.