Towards Plug-and-Play Protection for Meshed Distribution Systems with DG

TL;DR

This paper proposes a universal, plug-and-play relay-based protection scheme for meshed distribution systems with distributed generation, eliminating the need for system-specific settings and coordination studies.

Contribution

It introduces a communication-assisted, multifunctional relay design that adapts to all system conditions without requiring modifications or detailed coordination studies.

Findings

The protection scheme works across various system configurations.

Simulations demonstrate effective coordination without system-specific tuning.

The approach simplifies protection setup in complex distribution networks.

Abstract

Future distribution systems are expected to display increased complexity, mainly due to looped/meshed operation, switch between grid-connected and islanded mode and considerable integration of distributed generation. This paper investigates a plug-and-play protection solution for overhead distribution systems with such variable operation conditions, employing existing numerical relay capabilities. This solution is applied by designing plug-and-play, communication-assisted, multifunctional relays with integrated protection element settings, which apply universally to all distribution system conditions, rendering the protection scheme independent of a specific system. Hence, the need for user-defined settings or future revisions due to system changes is eliminated. The scheme ensures coordination between main line relays and backup protection of laterals, without a coordination study. There is no need to replace or modify existing lateral protection means for this purpose; only their known time-overcurrent curves are uploaded to the relays by the user. The scheme is described and evaluated through simulations in two test systems. Meaningful conclusions are finally derived.