STUDY OF THE ENERGY EFFICIENCY OF THE ELECTROMECHANICAL SYSTEM OF SMALL GS IN SHUNTING MODES OF OPERATION BY MEANS OF COMPLEX MODELLING.

A comprehensive mathematical model of a small hydroelectric power plant for a simulation modelling system has been developed. The model consists of the following simulation mathematical models: a hydraulic turbine with an adjustable guide device, its hydraulic network, an electromechanical system, and a reservoir model. These simulation models are based on the differential equations of electrical, mechanical, and hydraulic equilibrium and are designed to determine the values of currents, speeds, and performance of steady-state operating modes, taking into account the nonlinear properties of the equation parameters. To improve the adequacy of the complex model, a refined simulation model of an induction machine with loss detailing was applied and verified to specify the efficiency and permissible heating power in the motor and generator modes. The losses in steel are ac-counted for by their equivalent circuits. The information on the calculated values of the operating mode parameters allows deter-mining the value of the efficiency indicators of the hydroelectric power plant system under different operating conditions, which makes it possible to formulate optimal modes. Based on the results of a series of calculations with varying static head and open-ing of the blades of the axial guide apparatus, the regularities of changes in their optimal ratio according to the criterion of maximum electric power generated per unit of reservoir water flow used in the formation of the power plant's shunting mode were investigated. Based on the information on the value of the natural flow and the characteristics of the turbine unit, a stable level of static head is determined, which ensures the maximum generated electric power. The power plant's shunting mode was studied to determine the impact of changing the number of simultaneously operating units on the amount of electricity generated and changes in its capacity (the possibility of reducing the unevenness of the generated power by almost two times and increasing the minimum capacity by 30% was shown). Compared to the steady-state flow, the shunting mode provides an almost twofold increase in electricity generation and a threefold increase in efficiency, taking into account the differential cost of electricity by time of day. [ABSTRACT FROM AUTHOR]