Applying Variable Speed Drives To Control Pressure
Applying Variable Speed Drives To Control Pressure (on photo: ABB's Variable Speed Drives; credit:

Pressure Control Pump Station //

Using variable speed drives (VSDs) to control pressure reduces the electrical energy requirements by reducing the amount of hydraulic energy actually produced.

A basic pressure control pump station is equipped with one pump controlled by one variable speed drive (VSD). In some pump stations, pumps connected in parallel are a more efficient solution. Several parallel pumps can be controlled with one VSD controlling the master pump and contactors switching the other pumps on and off.

Figure 1 shows a set-up with parallel pumps using one drive to control three pumps.

Pressure control of a pumping system with one variable speed drive (VSD)
Figure 1 – Pressure control of a pumping system with one variable speed drive (VSD)

System Redundancy

To guarantee pump operation, even when a fault occurs, the pump system needs redundancy. In pump stations this means that a failure of one pump, motor or drive in a parallel installation does not cause a process interruption but the operation will continue with a limited capacity.

In order to have a replacement for a failed unit, a parallel system is needed! This means that each pump is controlled by an industrial drive for pump control.

Drives share information such as status of the drive, priority, running time, process feedback, etc. through a fiber optic link.

In a ring connection implemented with fiber optics it is possible to define the actions for the drives in the event of failure of the optical link in order to achieve 100% redundancy. No PLC is needed.

Figure 2 shows a system loop with three industrial drives in ring connection controlling three pumps.

Pressure control with three industrial drives
Figure 2 – Pressure control with three industrial drives

Might be interesting for you to try free Pump Efficiency Calculation Tool (MS Excel Spreadsheet).

Pump Efficiency Calculation Tool
Pump Efficiency Calculation Tool

Download Tool

Reference // ABB Application guide No. 2 – Using variable speed drives (VSDs) in pump applications

About Author //


Edvard Csanyi

Edvard - Electrical engineer, programmer and founder of EEP. Highly specialized for design of LV high power busbar trunking (<6300A) in power substations, buildings and industry fascilities. Designing of LV/MV switchgears.Professional in AutoCAD programming and web-design.Present on


  1. Goran
    Jul 05, 2016

    Dear Edvard,

    Can you explain your logic how to control 3 pumps with one VSD and 2 contactors. When sistem is started only VSD is on and frequency rises from 20Hz to 50Hz trying to reach SV of the pressure. If SV is not reached, one of slave pumps have to be started with contactor and it start directly at 50Hz. Should frequency of VSD have to be decreased to 20 Hz or to stay at 50Hz. Starting of slave pump will cause hydraulic impact and SV could be exceeded. What is your opinion?

  2. nand kishor kumar
    Oct 08, 2015

    i want to take your knowledge.

Leave a Comment

Tell us what you're thinking... we care about your opinion!