JUSTIFICATION OF THE MAIN PARAMETERS FOR HPP’S SUCTION PIPES

• Main Author: Bal’zannikov Mikhail Ivanovich
• Format: Article
• Language: English
• Published: Moscow State University of Civil Engineering (MGSU) 2015-09-01
• Series: Vestnik MGSU
• Subjects: hydropower plant; suction pipe; construction; justification of the parametres
• Online Access: http://vestnikmgsu.ru/index.php/archive/article/download/2629

Hydraulic turbine suction pipes at hydropower plants (HPPs) play an important role for providing high power indices of HPP operation. At the same time for channel type HPPs with vertical reactive hydraulic turbines curved large size suction tubes are used and this leads to great costs for their installation. That is why the significance of economic analysis for justification of the size of such suction pipes is underlined. Minimally possible sizes of curved pipes (height and length) are determined by hydraulic turbine normal operation requirements and are given in reference books. Nevertheless often such conditions arise when the correction of their size leading to their enlargement becomes inevitable. In particular, when there are rocks at a small depth below of the project position of the foundation slab it is feasible to increase a suction pipe’s height to place the foundation concrete on the strong rock. Or if it is necessary to make a motorway at the downstream side of a channel HPP lengthening of a suction pipe appears sensible. In such cases economic calculations are necessary on feasibility of suction pipe size change proposals. The use of an integral effect technique for such an analysis is proposed. The article provides a criterion for economic efficiency of the given technique. In conformity with it the calculations for a hydraulic turbine with 9 m diameter under acting head of 24 m are made. The calculation results are presented as graphs of dependencies of integral effect on varying parameters. The analysis of the results shows that a parameter being changed (suction pipe lengthening) has a distinct optimal value, which in the investigated variants is 2.5...3.0 m. Herewith a maximal value of economically justified hydrogenerator suction pipe lengthening satisfying the criterion adopted is in the range of 7.5...8.0 m. It is also shown that the value of the integral effect depends significantly on electric energy tariffs and the conditions of HPP operation.