An interposing relay (sometimes called an interface relay or isolation relay) is essentially a relay used to interface two circuits that have different electrical characteristics (e.g. different voltages, current levels, or common references). It “interposes” itself between a control circuit (e.g. PLC, sensor output) and a load or another circuit that may not be directly compatible. Key roles… Read More »
Magnetising inrush is a transient electrical phenomenon that primarily occurs when a power transformer is energized. It is not indicative of a fault but rather a normal response of the transformer’s magnetic core to sudden application of voltage. However, it poses significant challenges for transformer protection systems, which must distinguish this temporary surge from actual faults to avoid… Read More »
Medium Voltage (MV) switchboards are critical components in electrical distribution networks, responsible for controlling, protecting, and isolating electrical equipment. The power supply modes for these switchboards vary based on the required level of redundancy, reliability, and operational flexibility. These modes determine how supply sources connect to the busbars and feeders, ensuring continuity of power while minimizing downtime during… Read More »
Insulating materials are fundamental to the safe and efficient operation of electrical systems, serving to separate conductive parts from non-conductive ones and prevent unintended current flow. In high-voltage equipment such as motors, generators, transformers, and cables, insulation integrity directly impacts reliability, with studies estimating that up to 98% of electrical failures originate from insulation degradation due to factors… Read More »
In electrical power systems, substations and switchyards form critical nodes that ensure the efficient, safe, and reliable transfer of electricity from generation sources to consumers. While often discussed interchangeably in casual contexts, they exhibit distinct characteristics based on their functions, equipment, and placements within the grid. This comprehensive overview draws from engineering principles and industry practices to delineate… Read More »
The tan delta test, formally known as dissipation factor or power factor testing, is a fundamental diagnostic technique in high-voltage electrical systems. It quantifies the dielectric losses in insulation materials, offering critical insights into their condition and susceptibility to failure. In the realm of generators, this test is primarily applied to stator windings, which endure continuous electrical, thermal,… Read More »
In the field of electrical engineering, where the reliability of energy networks is paramount, maintaining the insulation of equipment is a critical challenge. An insulation failure can lead to costly outages, safety risks, or even widespread blackouts. Among the most effective and widely used diagnostic tools is the Tan Delta test, also known as the Dissipation Factor Test… Read More »
The transmission of electrical energy is a fundamental element of global power grids, and one of the main distinctions between systems lies in the frequency used: 50 Hz or 60 Hz. Most countries in Europe and Asia adopt a voltage of 220 V at 50 Hz, while nations like the United States, certain regions of Japan, and Saudi… Read More »
Vector algebra is a fundamental tool in electrical engineering, particularly in the analysis of circuits and protection systems. It allows for the representation of physical quantities, such as current or voltage, not only by their magnitude but also by their direction. This article highlights the importance of vector representation in simplifying calculations involving complex quantities, while providing a… Read More »
Directional earth fault protection, identified by the ANSI code 67N, is a specialized protection function used in electrical networks with a compensated neutral, typically employing a Petersen coil earthing system. This protection is designed to detect and isolate earth faults (single-phase-to-ground faults) in such networks by distinguishing the fault current in a faulty feeder from the capacitive currents… Read More »