Control Systems

Virtual Protection Relays Explained: Future of Digital Substation Protection

The digitalization of substations is reshaping how power systems are protected and controlled. Virtual Protection Relays (VPRs) represent a paradigm shift — moving protection intelligence from dedicated hardware to software-defined, virtualized environments. In this digital framework, IEC 61850-9-2 LE and Merging Units (MUs) are foundational standards and devices enabling this transformation by digitizing analog current and voltage signals… 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 »

What Is Electrical Power Automation? Definition, Components, and Benefits

Electrical Power Automation refers to the use of control, instrumentation, monitoring, and communication technologies to manage, regulate, optimize, and protect electrical power systems with minimal human intervention. It spans the generation, transmission, distribution, and utilization of electrical power. In other words, it’s about making the electrical grid or electrical system smarter, more reliable, more efficient, and safer by… Read More »

Modbus RTU vs Modbus TCP: Key Differences, Advantages & Use Cases

When setting up industrial automation or SCADA systems, one of the first communication choices you’ll face is Modbus RTU vs Modbus TCP. Both are based on the Modbus protocol, a widely used open standard for communication between programmable logic controllers (PLCs), sensors, and other field devices. However, while both share the same command structure, they differ significantly in… Read More »

What Are the Balls on Power Lines? A Complete Guide to Aerial Marker Balls

Have you ever looked up at power lines and wondered about those colorful balls hanging from them? These spheres, often orange, white, or yellow, are more than just decorations—they play a crucial role in safety. Known as aerial marker balls or visibility markers, they help prevent accidents by making power lines visible to aircraft and birds. In this… 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 »

Polarization Index (PI) and DAR Tests: Assessing Electrical Insulation Quality in 2025

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 »

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 »

Tan Delta Test: Generator Insulation Guide

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 »