Electricity Quality Problems in the 0.4 kV City Electric Networks

摘要

The article discusses the results obtained by monitoring the electric energy quality in 0.4 kV urban electric networks. It lists the main problems, which inevitably arise during the electric energy quality reduction. The reasons for the occurrence of low quality electricity are presented. It is shown that in this case, a malfunction of various power receivers occurs. It is indicated that earlier studies of electric energy quality issues mainly considered power supply systems and power receivers of industrial enterprises. However, the quality issues also arise in 0.4 kV urban electric networks, which supply office, administrative, public, residential buildings. These violations can occur in almost all groups of electric power quality indicators – slow voltage changes, voltage fluctuations, voltage asymmetry in a three-phase system, voltage non-sinusoidality. Therefore, developing measures to maintain the quality of electric power within acceptable limits in urban electric networks requires monitoring the electric power quality indicators. It is based on its results, that a set of measures to improve the quality of electricity should be developed. The article presents the examples of low quality electricity, including the cases when voltage fluctuations occur.