Evaluation of the performance of differential protection in the case of inverter-generated fault currents

Research output: Contribution to conferencesPaperContributedpeer-review

Abstract

The transient behavior of grid-forming converters changes significantly when the maximum current limit is reached. Conventional control methods based on the positive-sequence component can lead to non-sinusoidal current waveforms under unbalanced conditions and faults. This poses challenges for numerical protection relays, which are designed for generator-based systems. Consequently, protection technology must adapt to future grid structures with increased integration of decentralized power systems. In the short term, aligning grid-forming converter behavior with the operating principles of existing protection relays is essential. This article analyzes the dynamic performance of differential protection relays in relation to the currentlimiting methods used by converters. Conventional control methods will lead to sinusoidal deviations when non-symmetrical faults are present. It is shown that current limiting methods can affect the performance of the differential protection. Distorted short-circuit currents can block the fault trip of the differential protection by overfluxing detection. A novel control method is compared with a conventional approach for an unbalanced grid fault. Results show that the proposed method enables differential protection performance comparable to generator-based systems, ensuring fast and selective fault handling critical for grid reliability

Details

Original languageEnglish
Number of pages7
Publication statusAccepted/In press - 1 Apr 2025
Peer-reviewedYes

Conference

Title19th IET Conference on Developments in Power System Protection
Abbreviated titleDPSP Europe 2025
Conference number19
Duration1 - 3 April 2025
Website
Degree of recognitionInternational event
LocationBizkaia Aretoa
CityBilbao
CountrySpain

Keywords

Keywords

  • DIFFERENTIAL PROTECTION, NON-SYMMETRICAL FAULTS, GRIDFORMING CONVERTER, VIRTUAL SYNCHRONUS MACHINE, CURRENT LIMITATION, Differential protection, Non-symmetrical faults, Grid-forming converter, Virtual synchronous machine, current limitation