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UDC 628.1.2:658.26.004.18

Usachev A. P.

Control of centrifugal pump parallel operation

Summary

The problems related to the cable capacity of pumping units during their parallel operation (one with variable-frequency control, another one – without variable-frequency control) are considered. In the traditional control schemes (without variable-frequency control) the problem is solved by throttling of each pump with cable capacity levelling of their drive motors. This function is usually carried out by the operator in manual mode. Based on the conducted analysis an algorithm of pump control was developed that provided for their safe operation in the working area and maximum energy efficiency. It is proposed to carry out controlled throttling of the pump without variable-frequency control by controlling the position of the set point of the pump with variable-frequency control at the working area interface. To ensure failure-free operation of the pumping station in case of the pump with variable-frequency control emergency shutdown it is recommended to change the system of the pump without variable-frequency control for automated pressure maintaining with the help of throttling. To implement the given algorithm the use of a special process controller with the sufficient computing power (STK 500 type) and series SP 200 blocks is proposed.

Key words

power saving , frequency regulation , centrifugal pump , parallel operation , throttling