Category Archives: Electrical Testing

Performing Power Factor Test on Dry-Type Transformer During Commissioning

During transformer commissioning, one of the most important diagnostic procedures is the power factor test. This test assesses the dielectric losses in the transformer’s insulation system, which are directly related to insulation quality and integrity. For dry-type transformers, the power factor test helps identify potential insulation deterioration due to moisture, contamination, carbonization, or other degradation mechanisms that may… Read More »

Electrical Testing of Dry-Type Transformers

Dry-type transformers are integral to the electrical infrastructure of industrial, commercial, and institutional facilities. Because these transformers power critical systems, regular electrical testing and maintenance are essential to ensure safety, reliability, and performance. This article summarizes recommended electrical tests and maintenance practices for dry-type transformers rated 500 kVA and above, based on ANSI/NETA MTS-2019 (Maintenance Testing Specifications) and… 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 »

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

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 »

Tan Delta Test: A Detailed Guide for Engineers and Technicians

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 »