Application of an adaptive controller for controlling the rotational velocity of hydrogenerators taking into account the technological state of a Kaplan turbine

Abstract

The impact of oil leakages in a turbine on the main power system parameters is investigated in reactive hydraulic turbines with adjustable-blade runners (Kaplan turbines) installed at Maynskaya, Nizhne-Bureiskaya and Vilyuyskaya hydroelectric power plants. The main theoretical relations and conclusions were obtained by the methods of mathematical simulation and integral calculations in the MATLAB software environment. A method is proposed for monitoring leakages in the housing of an adjustable-blade runner and smoothing the fluctuations of various parameters (amplitude, rotational velocity, phase angle, active power and generator current) of the power system in the case of oil leak-ages. The control is performed by means of a sensor installed in the runner, a fiber-optic cable and an optical-electrical converter located along the shaft from the runner blades to the oil receiver of the corresponding hydraulic unit. The performed analysis of the obtained mathematical model (frequency response and Nyquist plots were built) relative to the basic parameters of the electrical energy generated by a hydraulic unit showed that the proposed method of monitoring oil leakages contributes to an increase in the operational stability of a hydraulic unit. When constructing the model, the following parameters of the hydraulic unit were taken into account: rotational angle of runner blades and opening angle of hydraulic turbine guide vanes. The developed block diagram can be used to compare variations in the parameters both without oil leakage control and taking into account the automated control system proposed by the authors. It is shown that the obtained logarithmic Nyquist plot can be used to monitor variations in the amplitude, as well as its smoothening, both under normal conditions and taking into account oil leakages in the hydraulic turbine housing.