Category Archives: Substation

Directional Earth Fault Protection (67N) Explained for Impedance-Grounded Networks

This article focuses specifically on directional earth fault protection (ANSI 67N) for electrical networks with an impedance-grounded neutral. We’ll be releasing more articles soon that explore how directional earth protection behaves in other grounding systems. The goal is to give you a complete, system-by-system view of how earth fault protection works. Stay tuned—there’s much more coming. In this… Read More »

Dry-Type Transformer: The Complete Guide to What, Why & How

The term dry-type transformer refers to an electrical transformer that relies on air or solid insulation instead of liquid for cooling and insulation. If your power-distribution system demands high safety, low maintenance, and environmental compliance — then a dry-type transformer may be the ideal choice. In this guide you’ll learn what a dry-type transformer is, how it works,… Read More »

Distance Protection Schemes: Working Principles, Types, and Comparison

Distance protection schemes play a vital role in ensuring reliable and speedy fault clearance on transmission lines. The fundamental idea behind distance protection is to measure the impedance between the relay location and the fault point, enabling the relay to detect faults within set zones. Conventional time-stepped distance protection, for instance, sets an instantaneous Zone 1 reach to about… Read More »

Virtual Protection Relays: Complete Guide to IEC 61850 Digital Protection

The digitalization of substations is transforming the way power systems are protected and controlled. Virtual Protection Relays (VPRs) are a major step in this evolution. Instead of using dedicated hardware devices, protection functions now run as software on virtual machines or high-performance computing platforms. This shift is made possible by standards such as IEC 61850-9-2 LE and devices… Read More »

What Is an Interposing Relay? Function, Uses & Benefits Explained

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 »

Understanding Magnetising Inrush in Transformers

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 »

Understanding MV Switchboard Power Supply Modes

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 »

What are the Differences Between Substation and Switchyard?

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 Transmission of Electrical Energy: 50 Hz vs. 60 Hz

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 in Electrical Engineering

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 »