Improving the Efficiency of Protection Devices with Zero Sequence Voltage Filters in Rural Electrical Networks

Rural electricity networks are characterized by low reliability and low power quality indicators. To protect electrical machines, devices with integrated voltage filters are used. The zero sequence voltage filter is the easiest in construction and most well-proven in operation device. However, with the existing power quality, this protection either causes false tripping or untimely operation. Today's element base allows constant monitoring of power quality at agricultural facilities. Using the monitoring data, a method to highlight the static and dynamic components of asymmetry in the supply network has been proposed. Experimental verification of proposals was carried out at poultry farms during energy inspection. The analysis of the received data confirmed the possibility of isolation of separate components of voltage asymmetry. On the basis of the research it was recommended to reconfigure the filter protection devices by detaching it from the static component of unbalance by changing the filter parameters. It is proposed to remove the dynamic component errors by introducing a time delay.