The connection of renewable sources to the grid. Influences and power quality issues

This paper presents results of power quality monitoring collected from transmission system operator (TSO) and several distribution system operators (DSOs) from Romania. The power quality monitoring system is realized in accordance with actual technologies, economic criteria, performance standards and technical codes issued by the Romanian Energy Regulation Authority (ANRE). The implementation of power quality policies in Romania based on the monitoring and corrective actions determined the improvement of quality of transmission and distribution services in power system. The challenges represented by the connection to the grid of new renewable sources have determined ANRE to issue dedicated regulations. The use of the power quality monitoring systems at the interface between TSO and DSO (Distribution Management System, Fault Recording System, Outage Management System) provides better solutions and leads toan increase in the quality of services. The influence of the short-circuit in the propagation of perturbation in power system represents a challenge within the existing context when many renewable sources are connected to the grid.