The article substantiates the necessity of using alternative energy to create electrical and thermal energy, satisfying
the needs of farms, workers of mining and geological surveys and the population living in decentralized areas. One of the
priority values is the use of resources of mountain rivers by building small and/or micro hydroelectric power plants. At
the same time, the designers are
... [Show full abstract] faced with the dilemma of selecting the design of the hydraulic turbine, as this unit is the
main element by which the energy stored in mountain watercourses is converted into mechanical and then into electrical
energy by means of an alternator. Taking into account the variability of such parameters of the mountain river as pressure
and flow rate of water supplied to the impellers of the hydraulic turbine, depending on the seasons and climatic conditions
of the area, it is required to conduct preliminary studies by building a simulation-laboratory stand.
Two alternating current electric machines are used to build a simulation-laboratory stand: an induction engine designed
to simulate the selected design of a hydraulic turbine; a synchronous generator designed to study the generator operation
modes at different values of water flow and pressure. In order for an induction engine to simulate the properties of
a hydraulic turbine, it is necessary to determine a mathematical or graphical representation of the mechanical characteristic
for a pre-selected hydraulic turbine design. Obtaining the mechanical characteristics of the hydraulic turbine is greatly
facilitated by using computer modeling with the application of the FlowVision software package. The main equations in
compiling the mathematical model of the propeller hydraulic turbine are the Navier-Stokes equation together with the
continuity equation.
The solution of these equations allowed us to obtain universal characteristics H = f(Pt), head as a function of hydro
turbine power at different values of the efficiency. The desired mechanical characteristic ω = f(Mt), angular velocity as a
function of the torque on the shaft of the hydraulic turbine is obtained from the universal characteristics of the turbine by
transforming them by program method. In the simulation stand the process of changing the pressure head or water flow
rate is reproduced by introducing a frequency converter (FC) into the power supply circuit of the asynchronous engine, in
the control system of which a nonlinear block (NB) is provided. With the help of NB, the electric drive realizes the
change in the head of the mountain watercourse in the form of a change in the rotation speed of the hydraulic turbine. The
asynchronous engine can imitate the properties of the hydraulic turbine if the FC is switched to the current source mode,
and the built-in current regulators in the electric drive control system, assembled according to the structure of the proportional-
integral link, are adjusted to the technical optimum. In this case, the current setting signals for the steady-state
modes of operation of the hydraulic turbine are supplied to the inputs of the current regulators from the output of the nonlinear
block.
