Understanding High-Voltage Circuit Breaker Nameplates — Part 2

Volney Naranjo, Megger Industry Topics, Spring 2022 Industry Topics

Along the extensive and complex electrical system infrastructure from generation to transmission and distribution, the wide variety of medium- and high-voltage circuit breakers (MV/HV CB) vary in size, interrupting medium, number of breaks per phase, and various other attributes. To help classify breakers and their attributes, they are all shipped with a nameplate stating the minimum information about specific mechanical, …

Microgrids: Old Concept on Steroids

Ed Khan, Doble Engineering Company Industry Topics, Spring 2022 Industry Topics

Microgrids are gaining ground in different parts of the world with each passing year. In the United States, one of the main drivers advancing the concept of microgrid was Hurricane Sandy. This hurricane, which hit the northeast part of the US in 2012, caused havoc with the transmission and distribution system. The advantages presented by smaller, self-sustaining grids began to …

Should I Do Power Studies In-House or Subcontract Them Out?

Roger Graver, PowerSight Industry Topics, Spring 2022 Industry Topics

For some companies, deciding whether to perform power monitoring studies with their own in-house professionals or subcontract the work out may be a real toss-up. There is no general right answer, but there is a right answer for you. That answer may change over time. This article is a guide to making (and revising) that decision. To be clear, this …

An Intelligent System for Condition Assessment of Power Transformers

Mohamed Khalil, PhD, Doble Engineering Company Industry Topics, Winter 2021 Industry Topics

The health index (HI) approach has been adopted widely as a tool to help asset managers prioritize their plans and actions. However, the conventional computation of HI, which is based on scoring and ranking, has several drawbacks. In this work, the fuzzy logic approach is used to build up an intelligent HI system to assess the condition of power transformers …

Understanding High-Voltage Circuit Breaker Nameplates

Volney Naranjo, Megger Industry Topics, Winter 2021 Industry Topics

Along the extensive and complex electrical system infrastructure from generation to transmission and distribution, the wide variety of medium- and high-voltage circuit breakers (MV/HV CB) vary in size, interrupting medium, number of breaks per phase, and various other attributes. To help classify breakers and their attributes, they are all shipped with a nameplate stating the minimum information about specific mechanical, …

MV/HV Circuit Breaker Testing Beyond Conventional Practices

Volney Naranjo, Megger Fall 2021 Industry Topics, Industry Topics

Conventional testing of medium- and high-voltage circuit breakers (MV/HV CBs) involves measuring the timing and travel of the main contacts and their corresponding resistors (pre- or post-insertion) if any, along with the current profile of the operating coils, and occasionally the timing of auxiliary contacts. This article explains several techniques available to improve or extend the scope of testing. Aspects …

How Grounds Affect Peak Voltage Due to Lightning

Al Martin, retired Industry Topics, Fall 2021 Industry Topics

Did you know that the most common characterization of a ground rod may not work for lightning? In 1997, an experiment at the International Center for Lightning Research and Testing (ICLRT) at Camp Blanding, Florida, challenged the predominant view that ground rods are essentially resistive. That experiment found that the waveshapes of lightning currents in a building grounding system and those entering the electrical …

Electrical Safety through the Lens of the Fire & Life Safety Ecosystem™

Derek Vigstol, National Fire Protection Association Fall 2021 Industry Topics, Industry Topics

Electrical safety is often described as a three-legged stool encompassing proper installation, routine maintenance, and applicable safe work practices. It is this relationship that sets the stage for what can best be described as the electrical safety ecosystem as it lives within the larger overall NFPA Fire & Life Safety Ecosystem™. This Ecosystem is made up of eight key elements …

Successful Application of AI Techniques: A Hybrid Approach

Dr. Tony McGrail and Tom Rhodes Industry Topics, Summer 2021 Industry Topics

Artificial intelligence (AI) systems provide promise in analyzing and evaluating power system data. There is currently a large push  to use AI and machine learning (ML) to help reduce time performing maintenance on transformers and predict where and when the next transformer will fail.1,2,3 Major companies in various industries are promoting and telling the wonders of AI and ML: managing …

Electrical Wear in High-Voltage Circuit Breakers Using SF6 Alternative Gases

Nicola Garaboldi and Javier Mantilla Industry Topics, Summer 2021 Industry Topics

Every current interruption involves an arc burning between the contacts of a circuit breaker (CB). The produced arc energy and associated pressure increase is used in gas circuit breakers to cool the arc region leading to current interruption. The same arc energy causes wear that can be separated into two main phenomena: • Nozzle ablation, which affects pressure build up, …