Pumping units control complexes

Pumping units control complexes

The pumping unit control complex (PU CC) is designed to improve the efficiency of pumping units.

The complex regulates the frequency of drive motors rotation by changing the frequency
of three-phase AC from high-voltage frequency converters.
The complex can be operated from a 3 kV, 6 kV or 10 kV network with a frequency of 50 Hz.

The introduction of PU CC provides:
- saving electrical energy by optimizing the maintenance of technological parameters;
- saving electrical energy when changing the flow of technical fluid due to the rapid response of the complex and exit to the optimum mode without the use of throttling;
- increase in reliability of operation and extension of the service life of electric motors, as well as the units and mechanisms driven by them by reducing mechanical loads during direct starts;
- increase the life of the pipeline by ensuring optimal hydraulic conditions;
- elimination of failures of instrumentation and automation equipment due to water hammer;
- reducing the accident rate of equipment and reducing the cost of repairs and maintenance, as well as reducing emergency production downtime;
- automated optimization of technological parameters with the possibility of integration into the APCS of the enterprise.
Pumping unit control complex (PU CC):
- performs sequential soft start and stop of drive motors of pumping units (hereinafter referred to as) without negative impact on the power supply network;
- manages the performance of any of the PU in the group;
- maintains a stable setpoint pressure in the supply line in the automatic mode without the participation of the operator by controlling one or more pumps in the group;
- eliminates hydraulic shocks in the pipelines of the network during the start-up;
- carries out remote control of the PU electric motor, providing a change in pump performance in the range: from minimum to maximum values with fully open valves;
- automatically enters backup PU into the work and displays working PU in a state of reserve or repair;
- monitors the status of the equipment of the complex in real time;
- in emergency mode, it performs direct PU starts from the main network with the subsequent regulation of the flow rate by means of the existing gate valves with the frequency control of the pump electric drives turned off.

The installation and operation of the complex can be carried out without changing the existing technological schemes.

The PU CC control complex has one or several channels of frequency control by electric motors with the possibility of connection to any electric motor of the PU group.

The high-voltage frequency converter ensures a soft start, braking of the PU electric drive and regulation of the frequency of its rotation in order to maintain the required technological parameters. The following technological protections and interlocks are taken into account:
- the prohibition of the inclusion of the bypass channel when working on the frequency converter;
- prohibition of the connection of the HVFCA output during the operation of the PU actuator through the bypass;
- the prohibition of the inclusion of the electric drive when a failure of HV SESAC cells.

The complex operates in the following modes:
- regular mode;
- emergency operation.

The standard control mode provides soft start, stop and regulation of the pump motor speed. The mode ensures the absence of starting currents of the drive motor. Regulation of the performance of PU is carried out due to the smooth change of the rotation frequency of the electric drive of the PU. The mode is characterized by high efficiency of the pump unit, is economical and is the main mode of operation of the complex.

Emergency mode is characterized by the fact that the power voltage is supplied to the PU engines directly from the network. In this case, the high-voltage frequency converter is not connected to the PU engines and its control is blocked. The PU capacity control is performed in this mode by adjusting the guide vanes that are included in the installed process equipment.
Emergency mode is used only when it is impossible or not necessary to work in normal mode. The mode is designed to increase the reliability of the complex.

The following components are included in the pumping units control complex (PU CC):
- pumping units (existing or newly commissioned);
- high-voltage motors for rated voltage 6kV or 10kV (existing or newly commissioned);
- high-voltage frequency converter of HVFC series;
- power switching equipment for voltage up to 10kV;
- group control station with implemented local ACS for a specific task;
- remote operator’s console with a graphic terminal and software with visualization of technological task management;
- pressure valves with electric motor;
- feedback sensors (pressure, flow, rotor position, level, etc.).

Additionally, it may be possible to install the complex in a modular or mobile building equipped with the following systems:
- ventilation and heating system;
- technical room lighting system;
- fire alarm system;
- security alarm system.
The structure of the complex depends, in general, on the number of regulated PU in the group, their connection scheme, control method, etc. It is possible to selectively control one PU from a group controlled by a single HVFCA frequency converter. At the request of the Customer, a different configuration of the complex can be provided, for example: installation of HVFCA for each PU, or installation of several HVFCA for one group, etc.

Below is an example of the implementation of PU CC with 2 PUs and 1 HVFCA. At the same time, a separate cell is provided for the power supply of HVFCA from SWG (switchgear) RU-6. Management is performed from the ROC (remote operator's console) with a graphic terminal through software with visualization. ROC is directly connected with the GCS (group control station), in the controller of which a local automated control system is implemented for a specific technological task. The scheme provides for a return to the previously existing control scheme to bypass the HVFCA in manual (emergency) mode. The scheme provides for the possibility of integration with the APCS.

Pumping units control complexes

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