Zhuk I. Methods and tools for the control of isolation on the "ground" of operational DC networks of hydroelectric plants

The object of study - the process of changing the state of isolation in the operation of cable lines operative DC hydroelectric power plants; purpose of this study is to improve the reliability of hydro and pumped storage plants by identifying damaged insulation networks operative DC at an early stage of their development and reduce the amount of fault "ground" poles networks operative DC data stations by means of network-wide improvement insulation monitoring and automated fault detection site. In this thesis theory methods of electrical circuits, the operator method for calculating transients; criterial programming methods; methods of probability theory and mathematical statistics. Theoretical results - the first time a method for predictive control to determine the damaged cable line networks operative DC by finding the difference between the current test signal of different frequencies in the positive and negative conductors of the cable line; the first study of patterns of change in isolation networks operative DC hydroelectric power plants from the effects of external factors; first developed a mathematical model predicting the likelihood of deterioration of insulation networks operative DC, depending on the parameters of short-term changes in resistance values of poles on the "land", which allowed to study the variation of currents in circuits from the effects of both external factors and modes of hydropower units; also developed a method for determining the deterioration of insulation networks operative DC that by taking into account the parameters of short-term changes in resistance values of poles on the "earth" reveals defects such networks in the early stages. Practical results are to reduce the number of fault poles networks operating dc current through the contact resistance less than 20 ohms, and in reducing the search time of the fault; in the development of network-wide control device isolation, which allowed us to obtain a high sensitivity (less than 100 ohms) to the current difference between the positive and negative conductors; in the development of the device software network-wide control of isolation. The degree of implementation - the results have been implemented in the branch "Directorate for Construction of the Dniester PSP" and the Branch "Kanev HPP" (JSC "Ukrhydroenergo") and in the educational process of Vinnytsia National Technical University. Scope (scope) - power: application area is the electric power industry.