Short circuit and grid protection behaviour of power electronic virtual synchronous machines

Research output: Contribution to conferencesPaperContributedpeer-review

Abstract

The integration of renewable energy sources into electricity grids increases the use of power electronic feeders. To ensure reliable grid integration, control methods are being developed to give these devices characteristics similar to synchronous machines, known as virtual synchronous machines (VSMs). However, VSMs cannot fully replicate synchronous machine behaviour, particularly during faults. Overcurrent capability is significantly reduced, and current limiting algorithms protect the power electronics, often distorting the current waveform. At TU Dresden's Chair of Electrical Power Supply, a 220 kV physical network model enables short-circuit testing on a transmission line. This model includes three stations, a double-circuit transmission line, and various consumers and feeders. A VSM, connected via an isolating transformer, feeds into the grid. Short-circuit tests at various locations force the VSM into current limitation. Measurements of currents and voltages at the VSM terminals and transmission line were analysed to evaluate distance protection relay behaviour. The study highlights current behaviour during faults with conventional current limiting and assesses whether protection devices accurately detect and switch off faults. Hereby, we observed conventional current limiting in positive sequence systems caused distorted residual currents during asymmetrical faults, leading to relay misoperations and incorrect fault loop detection in some cases.

Details

Original languageEnglish
Number of pages4
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