Water & Wastewater Pump Station Control Basic parts: Metering & current limiters Main switch chassis Telemetry & Control Pump controls Questions: -IP rating - material - soft-start or VSD - pump & station control method - other items ie fans, valves, flowmeters etc Gas seal section

Drives v Soft-starters Advantages -Unity power factor to supply - Wide supply voltage V, +10% - 15% (helpful where power supply can be unreliable) - Balanced 3 phase to motors - Variable or multiple fixed speeds - Provides only enough power to maintain selected speed (cost savings) - Starting current is less than full load current reducing costs if maximum demand tariffs are charged - Allows fine tuning of speed to maximise pumping system efficiency - Discreet IO, Modbus, Ethernet and other control options - Direct torque control for extended control of ramp up/down function - Pipe-fill, pump clean and alternation software Disadvantages - Purchase price 3 x that of comparable sized PSE soft-starter - Cooling air flow - More difficult to configure

Control methods Most pump stations are installed with multiple pumps, usually two or three, which are controlled either locally, via telemetry, or a combination of both. Each approach has advantages and disadvantages. One approach is to provide consistency across pump stations, making life easier for operators and electricians. This can be achieved by installing a MultiSmart controller, ideally with a comms connection to telemetry, and also to the drives/soft-starters. The controller can then look after pump alternation, be configured as a PLC to control valves and other items, and to provide an operator interface. Where a comms connection is available, it is possible to access motor currents, faults and other key information without control wiring or current transformers.

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