Control system of one-frequency one-pump constant pressure water supply equipment

Abstract

The invention discloses a one-frequency one-pump constant pressure water supply control system, which comprises a control unit (6) for controlling the operation of the system and controlling the output frequencies of frequency converters, a human-machine interface (7) for setting parameters of the system and monitoring operational data, the frequency converters (5a, 5b and 5c) for controlling the rotating speeds of water pump motors, and sensing instrument units (1, 3 and 4) connected with the control unit and used for acquiring external feedback information, wherein according to the control system, water pumps (2a, 2b and 2c) in a controlled pump group are matched with the frequency converters and controlled by adopting a common-frequency and common-speed control technology to implement constant pressure water supply.

Description

technical field [0001] The invention belongs to the technical field of water supply and control, and specifically refers to a one-frequency-one-pump constant-pressure water supply equipment control system. Background technique [0002] With the development of frequency conversion technology, using frequency conversion to realize constant pressure water supply has become a trend of urban water supply. In the traditional constant pressure water supply equipment, a frequency converter controls the constant pressure water supply system of multi-pump circulation, which is very popular in electrical design. Its control mode is one control two, one control three, ..., one control n (n is the number of water pumps), referred to as one control multiple control mode. Specifically, it means that the traditional constant pressure water supply equipment control system only includes one frequency converter, and the water pumps controlled by the control system, depending on the water supp...

AI Technical Summary

Problems solved by technology

[0006] (3) Impact on the pipe network: When the motor is loaded with the water pump, the moment the switch occurs, the water pump stops rapidly under the action of water pressure, resulting in a huge "water hammer" effect. While the water pump is damaged, due to high water pressure and Stator counter electromotive force is superimposed, and the motor will also bear the impact current of more than 10 times the rated current, which often makes the power frequency circuit breaker 1QF ~ 3QF trip, resulting in switching failure, and even damage to the motor

Due to the limitations of the above system design, handover failures often occur in engineering practice

[0007] (4) Influence on the outlet water pressure: the water supply pressure of the equipment cannot be smoothly transitioned when the power frequency increases and decreases the pump

[0008] (5) If the frequency converter fails: practice has proved that even the most advanced frequency converter in the world today is difficult to guarantee that there will be no failure

But now secondary water supply equipment manufacturers generally want to sell the equipment to far away cities, and often do not have this type of frequency converter in stock, even if there is stock, it will take a long time to airlift the frequency converter to the fault site Two or three days, at most four or five days, and during this period of time, the site of the fault generally has to stop the water, which affects the safety of water use

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