Tsyganenko B. Efficiency of the power distribution networks under increasing of their voltage class

This dissertation presents a new solution to actual scientific and applied task of developing new methods of reconfiguring the high voltage distribution networks based on mathematical devices of genetic algorithms and fuzzy logic, which provides an additional reduction of electricity losses and quality improvements, when increasing 6 (10 ) kV networks to 20 kV voltage class. A new method of reconfiguring the power distribution network at normal mode were developed by using of genetic algorithms, which on the basis of power network mode enables determination of an optimal scheme configuration so that losses of power transportation were minimal under conditions that standard quality of electricity of voltage at customers' connection points assured and conservation of a minimum connectedness of power network scheme and minimal economic losses from power underproduction. A new method of reconfiguration of the power distribution networks were developed specifying a stop or activation point of reserve switching jumpers by forming the rating values of reserve jumpers switches on the basis of mathematical apparatus of fuzzy multitudes in case of feeders' emergency stop, which ensures a minimum loss of power in post-fault conditions. The fuzzy logic controller for definition of ratings of switches of reserve crosspieces taking into account pressure losses in the most remote site, power factor on the main site is synthesised at a mode admissibility on a current. A procedure of genetic algorithm for formation of a network scheme configuration with backup jumpers in the operating mode were studied and fuzzy logic controller to find a configuration of network scheme configuration in postaccident mode with minimal loss of electricity at appropriate restrictions on voltage drop in final section, current value and power factor at main section were synthesized. Developed methods were used for decision making regarding reconfiguration of electricity distribution network of SD Tyvrivskie PS of Vinnitsaoblenergo PJSC in the designing scheme of transferring existing 6 kV networks to 20 kV voltage class. A model for switching criterion of distribution network to 20 kV voltage on the basis of the mathematical apparatus of fuzzy logic were developed for the first time, which allows by analyzing the network conditions, that defined for reconstruction, to set a priority for each of them with respect to 20 kV switching, which will make an opportunity to find a financing priority of investment projects and ensure an optimum use of funds. For a basis of the synthesized model of criterion linguistic definition of a priority transfer the distributive network on voltage 20 кV by mathematical reproduction by the fuzzy logic control unit of reasons the expert on the basis of knowledge base presented by linguistic predicates is accepted. A criterion for 6 (10) kV networks switching to 20 kV voltage for all possible variations of parameter values was fixed. The parameter values were accepted for the analysis of network conditions (total length of 6 kV lines, operational period of 6 (10) kV network, average length of 6 (10) kV feeder, load, tendency to load change, territorial load density, index of average duration of disconnection, index of average disconnection frequency, of power district population): - the network should not to be switched to 20 kV voltage under the value of priority ranging from 0 to 2.3; - the network should be switched to 20 kV voltage under the value of priority ranging from 2.3 to 4.7, subject to the feasibility study; - the network should be uniquely switched into 20 kV voltage under the value of priority exceeds 4.7. Adaptation of developed methods that implements the intellectual approaches to reconfiguration of power distribution networks enable to perform a reconfiguration of existing scheme when switching to 20 kV voltage class in optimal way and reduce the power loss by approximately 10% compared to the initial scheme.