Distance Protection of Lines Emanating From Full-Scale Converter-Interfaced Renewable Energy Power Plants—Part I: Problem Statement

Abstract

The fault ride-through (FRT) requirement of modern grid codes results in interactions between full-scale converter-interfaced renewable energy power plants (CIREPPs) and the protection systems of high-voltage transmission grids, which normally involve distance elements either as the primary or the backup relay. Such interactions are influenced by the CIREPPs' exclusive fault behavior, and have been left largely unnoticed in relaying literature. Part I of this paper develops a CIREPP model suitable for relaying studies, and highlights the CIREPP properties by which the protection system is endangered the most. Then, the operating scenarios leading to the malfunction of a distance relay that is located at a CIREPP substation and protects the adjacent line are unveiled. These scenarios include in-zone short circuits missed by the relay and incorrect tripping for out-of-zone faults, which would, in turn, neutralize FRT schemes implemented inside CIREPPs. The findings of this study also hold true for the ac lines emanating from voltage-sourced converter-based HVDC connections.