Experimental Assessment of Ground Fault Protection in Frequency-Selective Grounded Systems Fed by a Single Transformer
S. A. Saleh, E. Ozkop, Marcelo E. Valdes, Ahmet Yüksel, D. Jewett, Ahmed Al‐Durra, Julian Meng, Sergio Panetta
Abstract
This paper presents performance assessment of ground fault protection for systems supplied by a transformer, which has frequency-selective grounding. Frequency-selective grounding is a new grounding system that is designed to act as a solid-grounding for high frequency currents, and as a low resistance-grounding for low frequency currents. This grounding system is composed from a parallel <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">$R-C$</tex-math></inline-formula> circuit with an equivalent impedance able to affect system zero-sequence currents and ground potentials. Such effects on zero-sequence currents and ground potentials can directly impact the accuracy and response speed of ground fault protection. Effects of frequency-selective grounding on ground fault protection are experimentally assessed for different fault and non-fault events, when the transformer supplies linear and non-liner loads. Experimental results demonstrate responses of various implementations of ground fault protection to fault and non-fault events, when the protected system has frequency selective grounding. Moreover, presented results and discussions aim to demonstrate the ability of frequency-selective grounding to support the operation of ground fault protection during different loading conditions and fault events.