Faults Monitoring System in the Electric Power Grid of Medium Voltage

Abstract

In electric power to medium voltage one of the service quality factors is to ensure the continuous supply of electricity to the customer. This work aims to develop a fault monitoring system based only in one variable: the electric current. The purpose is to develop a flexible and scalable system so that any electrical grid that can identify the cause and location of the failure in the medium voltage of electric power grid, contributing to improve the service quality of the grid. Also, the system can be easily adapted to monitor environmental parameters to generate alerts on natural catastrophes. The neutral system that is implemented (grounded, impedance grounded or ungrounded) is an important factor, in this work the ungrounded system is evaluated. In this paper three different algorithms have been developed: System A, system B and C. System A monitors the nominal value of electric current in each line of the electric power grid, system B monitors the value of electric power in each transformer station and system C compares the current at the begin and end of each line of the grid, checking if there is any discrepancy between them. All algorithms were tested in simulation mode and the most flexible, system C, was implemented in laboratorial prototype. It has been verified that for evaluating the monitoring system it is necessary to analyze the following parameters: real-time fault detection and location, monitoring before the distribution line protections act and the ability to adapt according to changes in the electric power grid, improving the service quality.