Unbalance Level Regulating Algorithm in Power Distribution Networks

Abstract

The paper dwells on the unified power quality indexes characterizing the phenomenon of voltage unbalance in three-phase systems. Voltage unbalance is one of the commonest occurrences in the town mains of 0.38 kV voltage. The phenomenon describes as inequality of vector magnitude of phase voltage and shearing angle between them. Causes and consequences of the voltage unbalance in distribution networks have been considered. The algorithm, which allows switching one-phase load, has been developed as one of the methods of reducing the unbalance level. The algorithm is written in the function block diagram programming language. For determining the duration and magnitude of the unbalance level it is proposed to introduce the forecasting algorithm. The necessary data for forecasting are accumulated in the course of the algorithm based on the Function Block Diagram. The algorithm example is given for transforming substation of the urban electrical power supply system. The results of the economic efficiency assessment of the algorithm implementation are shown in conclusion. The use of automatic switching of the one-phase load for explored substation allows reducing energy losses (active electric energy by 7.63%; reactive energy by 8.37%). It also allows improving supply quality to a consumer. For explored substation the average zero-sequence unbalance factor has dropped from 3.59% to 2.13%, and the negative-sequence unbalance factor has dropped from 0.61% to 0.36%.

The Power Quality Improving and its Losses Reducing with Balancing Devices

“…Numerous publications on the considered networks operating modes study are devoted to their functioning consideration in low power quality conditions [1][2][3][4][5][6][7][8]. Many years research in this area have allowed to establish that the most characteristic and objective 0.38 kV networks operation modes is the asymmetric mode (AM) [9][10][11][12][13][14]. On the one hand, these modes lead to an increase in unproductive electricity losses, including the fire hazardous situations possibility [15][16], on the other hand, to a significant decrease in the electricity quality characteristics, which leads to inadequate electric receivers operation.…”

“Green technologies” elements by the individual residential buildings internal electrical networks operation

“…This is due to the such networks saturation with new transformation means (for example, photovoltaic plants), as well as intelligent means that allow modes automatic control without human intervention (for example, flows that degrade the power quality). A significant publications number are devoted to the electrical networks various model's creation and their operating modes analysis [1][2][3][4][5][6][7][8][9]. Thus, a technologies use, which allow automating the electricity consumption processes, in order to increase its efficiency during the IRB internal electric networks modernization, can also be rightfully attributed to "green technologies".…”