Assessing the Trend of Power Quality Indicators in the Electric Distribution Networks Using a Regression Models-Based Approach. Case Study in Romania

The electric distribution system is a dynamic and complex system, structured and hierarchical by voltage levels (high - 110 kV, medium - 20, 10, 6 kV and low - 0.4 kV), such that any decision taken to improve the power quality at a certain level influences strategies from all other levels or same level. In this context, the power quality analysis must incorporate all partners (consumers, energy producers, and distribution network operators) so that improvement strategies consider all factors (technical, economic, or environmental) that have a mutual influence. The paper aims to perform a quality analysis of distribution service for all Romanian distribution network operators and determine the trend of some performance indicators (System Average Interruption Duration Index and System Average Interruption Frequency Index) using a regression models-based approach. The results showed that each indicator associated with each distribution network operator should have the best regression model with the lowest estimation errors. The identified regression models led to an average value of the two performance indicators of 5%.