ANALYTICAL METHODS USING IN DETERMINATION OF HPP’s TUNNELS OPTIMAL DIAMETERS

Abstract

In the paper comparative economic efficiency criteria (in theAnglosphere institutional economics as a productive efficiency) areconsidered for optimal sizes determination of HPP’s tunnels. Thereduced cost of different energy objects (3) that generating electricity in grid are used as an objective function for optimal diameter definition. Two-part summary reduced cost function (4) is base for F.F.Gubin's (8) and M.F.Gubin's (11) analytical methods of HPP's tunnel optimal diameter definition. F.F.Gubin's two-part summary reduced cost function (4) include derivation cost (cost of building and  exploitation tunnel) and cost of replaced Heat Power Plant (power plant which compensates for lost hydro power in grid due to head losses in the tunnel). Three-part summary reduced cost function (5) is base for Orloff's analytical method (12) of HPP's tunnel optimal diameter definition. Orloff included fuel cost for Heat Power Plant in reduced cost function additionally. The author offered to use the fourpart reduced cost function (6) for tunnel optimal diameter definition (13). The four-part reduced cost function consist derivation cost, replaced Heat Power Plant cost, fuel cost for Heat Power Plant and cost of hydropower house linked with tunnel.Reduced cost function differentiation and solution of the equation (7) allowed authors to obtain analytical methods for determining the optimal diameter of the HPP's tunnel. The equation (7) areencompassed by the more general engineering concept that eitherHPP's structure parameter is efficient or optimal when it minimizestotal cost for power production by the power industry.There are calculations of Mtkvari HPP's tunnel optimal diameter byforesaid analytical methods. In the table presents results ofcalculations by the foresaid methods (8), (11), (12), (13), and by the Bundshu's method (9) and by the Schaveleff's empiric formula (10). A comparative analysis of the results given in table allowed the author to make the following conclusion. The full account of the replaced Heat Power Plant reduced cost, which requires running fuel costs, in the objective function of the summary reduced cost for the power tunnel, leads to an increase in the size of the facilities HPP, and in turn, to increase the participation of its power in the grid, in general.That is, incomplete consideration of compensation for head lossesand, consequently, lost power of the HPP, leads to unreasonable useof more expensive energy resources Heat Power Plant.