Water & Wastewater Treatment

6 | MAY 2020 | WWT | www.wwtonline.co.uk The Talk: opinion SPONSORED BY MARTIN RICHARDSON, WATER FRAMEWORK MANAGER How smart functions unlock AC drives' potential Martin Richardson, Water Framework Manager for ABB Motion UK, explains how harnessing some of the lesser known functions in variable speed drives (VSDs) helps achieve AMP7 goals. V ariable speed drives (VSDs) are widely used by the water industry to control flow rates and save energy within pumps. Yet VSDs have built- in smart functions o•en overlooked by users, but which can enhance reliability and durability of a pump system. Capex and Opex can be reduced, while activating protection functions and advanced features can lower maintenance costs. Smooth pressure control The multi-pump function ensures smooth pressure control and continuous operation of up to eight pumps running in parallel, without the need for additional controllers. Each pump is controlled by its own VSD, with one being speed adjusted and additional drives started and stopped when demand requires. This results in smooth control with no pressure peaks. Blockage detection/cleaning Blockage detection means the drive cleaning function automatically switches between minimum and maximum pump speed to clean the impeller, quickly returning flow rates to normal and avoiding reduction in service. This avoids costly pump removal and associated health and safety implications. Pump protection A set of programs protect the pump against pressure variations outside of acceptable limits. Should pipework rupture, minimum pressure protection automatically runs the pump motor at a predefined speed to avoid dirty water filling the pipeline. Other protection programs include high pressure, inlet and dry run. Combined with the condition monitoring curve, this feature ensures the greatest protection for pumps, without the need for external sensors. Condition monitoring Continuous monitoring of the motor torque across the speed range, using a curve programmed into the VSD, enables high and low limits to be configured. Thus, if the operating torque exceeds the expected range, the VSD flags a fault in the pump system. Faults include blockages on the suction side, bearing issues, pump ragging or efficiency deterioration. Water hammer and pressure transient reduction So• pipe fill function manages the pressure when filling a pipeline by gradually increasing the pressure over a pre-set time. This avoids sudden pressure peaks, reduces water hammer risk and avoids pipework-damaging pressure transients. The quick ramp feature assists with the smooth closing of non-return valves, reducing the impact that the valves have on pressure transients. LOWCARBONFOOTPRINT. TRUELONG-TERMSUSTAINABILITY. WastewaterTreatment At70-90%LessOPEX FROMWATERSUPPLYTOWATERRE-USE

• Cover