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UDC 628.1:658.26.004.18
Moiseev A. V., Riffel E. V., Furmanova Yu. I., Syryakov V. V., Mazepo M. V.
Introduction of energy saving measures in Krasnodar Vodokanal
Summary
The aspects of efficient energy consumption by water and wastewater utilities are of primary importance. In order to reduce the energy consumption constituent of the production costs certain energy saving measures are introduced aiming to the development and improvement of the process technologies, upgrade of equipment and controls. This approach is provided by the development of market relations, deficiency of energy resources and, consequently, by the energy price increase. The energy consumption pattern of an enterprise is determined by the type of products manufactured or services rendered. The principle procedure of an energy audit of the pumping stations operated by Kransnodar Vodokanal; the basic technical solutions on the water supply upgrade are presented alongside with the comparison of the calculated and actual cost savings resulted from the introduction of the energy saving measures.
Key words
water supply system , pumping station , power saving , energy audit , frequency regulation
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UDC 621.65:62-531.3
Usachev A. P.
Method of estimating the efficiency of pumping unit frequency regulation (to be discussed)
Summary
The method of estimating energy saving from using frequency regulation of the pumping unit capacity in water supply systems is presented. The estimation of the capacity efficiency of pumping units is carried out only from the energy saving resulting from the use of frequency regulation instead of throttling (other saving components are not considered). To estimate energy saving it is required to compare the power consumed from the grid in the existing scheme of the regulation by penstock gate throttling and in the frequency regulation scheme. Then the energy saving in monetary form shall be compared with the expenses for retrofitting the frequency regulation system. The method is based on the graphical analysis of the pump operation point parameters in the operating group and optimized for the use in water supply systems operating by the pressure.
Key words
capacity , power saving , frequency regulation , pumping unit , efficiency evaluation , throttling
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DOI 10.35776/MNP.2020.01.06 UDC 621.65:62-531.3
Usachev A. P.
Method of evaluating the effectiveness of frequency regulation of the performance of sewage pumping units
Summary
The method of evaluating energy savings through the use of frequency regulation of the pumping unit performance at sewage pumping stations is considered. The method is based on a graphical analysis of the parameters of the operation point of the pumps in the working group and is developed for the use in sewer networks that operate according to the level in the receiving tank. The proposed method of evaluating the effectiveness of frequency regulation at sewage pumping stations has been proved by many years of experience of using and is precisely evaluative. Energy savings at sewage pumping stations are significantly lower than at water pumping stations. This applies to the systems with start/stop control because the effect of frequency regulation consists in reducing the velocity of fluid in the pressure pipeline. The bigger the dynamic component of the network characteristic in relation to its static component (in the range of the station capacity change), the stronger effect is manifested. In practice, this is extremely rare. The energy savings in the above examples with the start/stop mode does not exceed 10% (excluding the losses in the frequency converter).
Key words
sewerage pumping station , power saving , frequency regulation , pumping unit , efficiency evaluation
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УДК 621.65:62-531.3:628.1/.2
Bagaev Iurii, Karpov N. V., Usachev A. P.
Specific features of frequency regulation of parallel pumps
Summary
One of the options of energy efficient operation of pumping units at the water and sewage pumping stations under pump impeller speed variation with the help of variable-speed electric drives widely used at present time is considered. One variable-speed electric drive is installed either for a group of operating units or on a single pump. Installing a variable-speed electric drive on each operating unit at first sight seems to be a very expensive measure; therefore more often one electric drive is installed for a group of pumps (2–3 units). However, in this case cavitation processes can arise, the dynamic loading on the pump shaft and bearings can increase, the lifting efficiency can decrease, and in the long run the pump energy efficiency can drop. The data of the theoretic and practical substantiation show that installing variable-speed electric drives on each operating pumping unit provides for weakening of the above-mentioned shortcomings, whereas the energy efficiency improves.
Key words
energy efficiency , pumping station , frequency regulation , centrifugal pump , pump capacity
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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
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