The restricted earth fault (REF) relay is a type of differential protection which is used for detection of internal ground faults of power transformers. But, during external faults and transformer energization conditions, the probability of current transformer (CT) saturation increases. Thus, the spurious differential current due to CT saturation, can lead to REF relay maloperation. In this pap...

This paper proposes a restricted earth fault protection based on the wavelet transform (REFW) for detecting ground faults close to transformer neutral point (turn-to-ground faults) and supporting conventional phase differential protection, which presents limitations in this kind of faults. The proposed REFW uses only high-frequency components instead phasor estimation, speeding up detection tur...

In this paper, various methods of providing restricted earth fault protection are discussed. The proper operation of high and low impedance Restricted Earth Fault (REF) protection for various applications has been discussed. The maloperation of a relay due to improper placement of CTs has been identified and a simple/unique solution has been proposed in this work with a case study. Moreover, it...

< p>The restricted earth fault (REF) protection is provided for electrical power transformer in order to sense internal faults, mainly because it more sensitive than the main differential protection. However, The REF relay may maloperate when current (CT) saturation happens following a severe external fault. In this paper, new simple algorithm proposed scheme which realized by considering four ...

A restricted earth fault (REF) protection element provides sensitive detection of ground faults near the neutral a transformer or generator. The sensitivity gains from REF are especially more valuable when equipment is low-impedance grounded phase differential (87T) ineffective. However, faces several challenges in systems, which becoming prevalent inverter-based resource (IBR) plants. Dependab...

Introduction: Extensional fault scarps on Mars bear a striking resemblance to fault scarps on Earth, including geometric features such as horsts, grabens, relay ramps and breached relay ramps, en echelon arrangement of faults and grabens, and scaling characteristics [1], [2], [3]. Other surface features associated with extensional faulting on Mars are lines (" chains ") of circular topo-graphic...

This paper presents a novel transient current differential algorithm for earth fault detection in unearthed (isolated) and compensated neutral medium voltage (MV) networks. The proposed algorithm uses the transient residual currents, which are very sensitive for earth faults detection. The transient values of residual currents are calculated for each feeder in the network and used as an earth f...