Influence of the Renewable Energy Sources on the Energy Efficiency of Electric Distribution Networks

Abstract

The total installed capacity of renewable energy sources (RES) in 2021 reached almost 10 percent of the installed capacity of UES of Ukraine. This became possible due to state incentives in the form of a “green tariff”. However, the lack of a reasonable approach to determining the point of connection of RES to the electric network (EN) and its power has led to the decreae of the effectiveness of the EN operation.

Due to the incommensurable capacities of RES and consumers connected to one feeder, losses of active power increase, indicators of the quality of electric energy (voltage deviations) deteriorate, and elements of the electric network (power transmission lines, power transformers) are overloaded. All this is aggravated by the fact that ENs were designed and built according to the principles of centralized power supply, for which the appearance of counterflows of electricity is an abnormal mode.

Photoelectric plants, which make up almost 80 percent of RES in Ukraine, have the technical possibility to realize the impact on the flow of reactive energy in the network. This possibility was confirmed by analyzing the results of field experiments on operational objects and mathematical modeling by means of Simulink Matlab.

Optimization of the reactive power flows is the most effective means of reducing active power and energy losses and improving electrical energy quality indicators. Therefore, the paper proposes a method for determining the amount of reactive power generated by a photovoltaic plant depending on its connection point and network configuration.