Method and arrangement for controlling a pumping station
AssigneeABB AB
InventorsSrikanth Venkatachari, Mikael Holmberg
Life of this patent
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Abstract
A method and an arrangement for controlling a pump station includes measurement of the surface level of a liquid (465) by means of a sensor (452) and controlling the electric drive (401, 420, 430) of the pump (440) to a predetermined speed of rotation when a specific surface level value has been reached. This predetermined rotation speed value is preferably the rotation speed at which the ratio of the flow rate to the consumed power, i.e. the efficiency, is optimal. The measurement of the surface level and the related data processing for control of the pump are performed in a frequency converter (420) in conjunction with the control.
Claims27
A method for controlling a pump station, a pump included in the pump station transferring liquid from or into a tank and said pump being controlled by an electric drive comprising a frequency converter, the method comprising the step of:
- measuring the surface level of a liquid in the tank by means of a sensor (205),
- controlling the activation of the pump on the basis of the measured surface level (206-213),
- selecting a first value of the liquid surface level,
- selecting as the value of the first rotation speed of the pump substantially the value at which the amount of transferred liquid relative to the consumed energy is at maximum and
- monitoring the moment when the surface level reaches said first value of the liquid surface level from a predetermined direction (206) and controlling as a consequence of this detection the pump rotation speed to said first value (204, 207) of the rotation speed,
- said monitoring of the surface level and control of the rotation speed being performed in a frequency converter.
A frequency converter (420) for the electric drive of a pump station, the pump station comprising a liquid tank (460), a pump (440) and an electric drive (401, 420, 430) actuating the pump, characterised in that the frequency converter (420) comprises
- means (422) for storing a first value of the liquid surface level,
- means (422) for storing a first value of the rotation speed of the pump,
- means (423) for measuring the liquid surface level on the basis of a signal received from the sensor (452),
- means (421) for detecting the moment the liquid surface level reaches said first value of the liquid surface level from a predetermined direction and means (420) for controlling the rotation speed of the pump to said first value of the rotation speed as a consequence of said detection so that said first value of the rotation speed is substantially the value at which the amount of transferred liquid relative to the consumed energy is at maximum.
Dependencies are inferred from the claim text.