A Novel Principle of Current Differential Protection for Renewable Energy Station

In the context of building a new power system dominated by renewable energy sources, the integration of high proportion of renewable energy and high proportion of power electronic equipment imposes stricter requirements on power system protection. The current differential protection, as the main protection for the outgoing line of renewable energy stations, has a significant impact on the development and utilization of renewable energy and the stable operation of the power grid. Most of the existing studies start from the specific fault characteristics of renewable energy sources, and improve the performance of differential protection by modifying and supplementing criteria. This paper analyzes the phase and amplitude relationships of each phase current on both sides of the outgoing line of the renewable energy station, proposes a novel principle of current differential protection based on cross compensation, and verify the performance of proposed protection by building a model in PSCAD/EMTDC.

I. Introduction

With the increasingly prominent issues of fossil energy shortage, environmental pollution, and greenhouse effect, countries around the world are actively promoting low-carbon energy systems. The widespread application of clean energy such as wind, solar, and tide will promote the transition of global energy utilization from fossil fuels to renewable energy. In June 2023, the International Energy Agency released the “Renewable Energy Market Update - Outlook for 2023 and 2024” report, which predicted that global renewable energy growth would be approximately 440GW in 2023, with new photovoltaic installed capacity accounting for 65% of the total^[1]. As early as September 2020, China has proposed to strive to achieve the dual carbon goals of carbon peaking by 2030 and carbon neutrality by 2060, and the construction of a new power system with renewable energy as the main body proposed in the 14th Five Year Plan has become an important area under the dual carbon goals^[2].