Abstract: This paper proposes a novel protection method for single line-to-ground (SLG) faults in ungrounded low-inertia microgrids. The proposed method includes microgrid interface protection and unit protection. The microgrid interface protection is based on the difference between the zero-sequence voltage angle and the zero-sequence current angle at the microgrid interconnection transformer ...

Power transformer is a major component of power system and it’s correct functioning is vital to system operations. It is quite expensive and has no substitute for it’s major role. It is therefore, very important to closely monitor the in-service behavior to avoid costly outages and loss of production. Many devices such as Buchholz relay and Differential relay have been evolved to monitor servic...

A fully integrated X-Band quadrature VCO is presented. The VCO is implemented using transformer-coupled resonator in 0.18 μm CMOS technology, in which two VCOs are coupled by direct current modulation method to generate I-Q signals. The VCO is realized employing the drain-gate transformer feedback configuration proposed here. This allows VCO to use the quality factor enhancement in coupled reso...

259 Lines are protected by overcurrent-, distance-, or pilot-relaying equipment, depending on the requirements. Overcurrent relaying is the simplest and cheapest, the most difficult to apply, and the quickest to need readjustment or even replacement as a system changes. It is generally used for phaseand ground-fault protection on station-service and distribution circuits in electric utility and...

< 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 ...

Geomagnetically induced currents (GICs) are referred to as the quasi-dc current flows in power networks, driven by complex space weather-related phenomena. Such a potential threat delivery capability of electrical grids. To mitigate detrimental impacts GICs on critical infrastructures, should be monitored systems. Being inherently dc from frequency point view, components are, however, challengi...

Magnetizing inrush currents are known as the most critical potential threat in maloperation of transformer differential protection. Therefore, there is a need to detect current from internal fault avoid protection maloperation. Due possibility (CT) saturation at high level and current, discrimination algorithm should function appropriately CT conditions. Here, method developed based on rate pha...

Abstract In power systems, busbars connect important components such as generators, transmission lines, and loads. A typical fault occurrence on the busbar may result in isolation of faulty sections from other normally operating parts system resulting differential protection operation. Although main busbars' scheme is protection, its operation significantly affected by magnetic saturation curre...