Research on High-Impedance Ground Fault Detection Method in PV Distribution Network Based on Zerosequence Current Characteristics

Résumé fourni par la source

With the large-scale integration of photovoltaic (PV) power stations into distribution networks, traditional relay protection faces new challenges in detecting high-impedance faults (HIF). HIF is often accompanied by arc discharge, exhibiting weak fault current and inconspicuous features that are difficult to be detected by conventional protection devices. Especially in PV-integrated distribution networks with multiple power sources, the characteristics of fault current become more complex, reducing the adaptability of traditional detection methods. This paper establishes a distribution network model including PV power stations based on the PSCAD/EMTDC simulation platform, and thoroughly analyzes the time-domain and frequency-domain characteristics of the zero-sequence current under HIF conditions. On this basis, a time-domain analysis method based on the concavity and convexity of the second derivative of the zero-sequence current and a frequencydomain analysis method based on the amplitude and phase characteristics of the third harmonic are proposed, constructing fault criteria from both the dynamic variation and harmonic structure of the fault current. The algorithms are tested and verified on both the system side and the PV side. The results show that the proposed method can effectively identify arcinduced high-impedance ground faults in PV-integrated distribution networks, demonstrating strong anti-interference capability and adaptability. It provides a new approach and methodology for addressing the challenges of high-impedance fault detection in distribution networks with PV integration.

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