Optimal Coordination of Over-Current Relays in Microgrids Using Unsupervised Learning Techniques

Sergio D Saldarriaga-Zuluaga,Jesús M López-Lezama,Nicolás Muñoz-Galeano

doi:10.3390/app11031241

Sergio D Saldarriaga-Zuluaga, Jesús M López-Lezama + Show 1 more

Open Access

https://doi.org/10.3390/app11031241

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Abstract

Microgrids constitute complex systems that integrate distributed generation (DG) and feature different operational modes. The optimal coordination of directional over-current relays (DOCRs) in microgrids is a challenging task, especially if topology changes are taken into account. This paper proposes an adaptive protection approach that takes advantage of multiple setting groups that are available in commercial DOCRs to account for network topology changes in microgrids. Because the number of possible topologies is greater than the available setting groups, unsupervised learning techniques are explored to classify network topologies into a number of clusters that is equal to the number of setting groups. Subsequently, optimal settings are calculated for every topology cluster. Every setting is saved in the DOCRs as a different setting group that would be activated when a corresponding topology takes place. Several tests are performed on a benchmark IEC (International Electrotechnical Commission) microgrid, evidencing the applicability of the proposed approach.

Highlights

Modern societies are highly dependent on the supply of electrical energy for their daily functioning
Microgrids play a key role in this solution, since they facilitate the integration of renewable energy resources in distribution systems through distributed generation (DG) [4]; such integration brings new issues regarding their control and operation [5]
This paper proposes a flexible approach for the optimal coordination of directional over-current relays (DOCRs) in microgrids that host DG and feature several operational scenarios or topologies

Summary

Introduction

Modern societies are highly dependent on the supply of electrical energy for their daily functioning. The per capita energy consumption has steadily grown, due to the increasing of industrialization and world population; so, fossil fuel and conventional energy resources might not be sufficient for meeting humanity’s energy needs in the medium term [1]; in other words, the traditional electrical network will not be enough to meet the growing energy demand. For overcoming this issue, the massive implementation of renewable energy resources and efficient energy storage systems have been thought as the future of power generation [2,3]. According to [7,8], protection systems in microgrids must face two remarkable challenges: the first one corresponds to their inherent dynamic behavior, due to intermittent loads and generators, and the second one is related to their operating characteristics (grid connected or islanded)

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