All pumps require a control strategy, from basic manual start/stop systems to highly automated, multiple-pump variable-speed systems. In complex systems, the flow and head generated by the pump can be controlled by a Variable Speed Drive (VSD), particularly when the system demands a variety of operating conditions and maximum system efficiency for each.
Within the range of control strategies available, OneStone has particular experience in the development of real-time control strategies for large pumping stations in water distribution systems where the pump station must fulfil a range of operating conditions and functions. The multiple objectives of a pump station control system can include:
- maintaining constant pressure (for booster systems)
- maintaining constant flow rate (for transfer systems)
- maintaining constant water level (for sumps)
- minimising surge.
As the design, implementation and ongoing operation of a pump station control system requires coordinated and multidisciplinary input, it can be a challenge to ensure the control strategy remains fit-for-purpose and the pump station performs efficiently as designed. Any system changes or upgrades can lead to the pump station operating unpredictably, which may cause:
- inefficient pump operation and increased energy use
- damage to the system due to water hammer
- increases in system downtime and maintenance due to poor performance
- instability that can extend to the rest of the network, such as fluctuations in pressure that can impact connected customers, or fluctuations in flow that can cause system-wide inefficiencies and failures in chlorine dosing facilities
- lost confidence by remote operators in keeping the system under stable and controlled conditions.
A significant challenge in implementing the design of a real-time control strategy for a pump station is ensuring it meets the needs of all stakeholders, and all systems it intersects with.
|Stakeholder||Control strategy requirements|
|Planners||Ability to determine daily, weekly, yearly and future projections of water distribution|
|Achieve water supply objectives (pressure, flow rate)|
|Predict energy usage|
|Engineers||Meet operational requirements|
|Compatibility with electrics (motors, VSDs, Programmable Logic Controllers (PLCs)|
|Compatibility with mechanical equipment (pumps, motors)|
|Operators||Ability to achieve specified targets for water distribution with required functionality and ease of use|
OneStone works closely with all project stakeholders to ensure that multiple control objectives can be efficiently achieved within a coherent control system design.