This article presents a functional test procedure for a sudden pressure relay. The sudden pressure relay trips when it detects a sudden increase in gas pressure due to a fault internal to the transformer tank. Recommendations for mounting the relay and a procedure for post-analysis following field trips are also provided. The sudden pressure relay (Figure 1) offers three main …
Welcome to the 2019 Winter Edition of NETA World
As humans, we are drawn to one another and communicate with each other using a variety of methods. Good and effective communication is an essential tool to achieve productivity and maintain strong and lasting working relationships at all levels of an organization. What every interaction has in common is the need for clear and effective communication. In this issue of NETA …
Emerging Technologies
Wikipedia defines emerging technologies: “Emerging technologies are technologies that are perceived as capable of changing the status quo. These technologies are generally new but include older technologies that are still controversial and relatively undeveloped in potential.” In this issue, we look at some emerging technologies that are in use now or might be in the future. This Tech Quiz is …
Another Test for Lightning Protection
It doesn’t take an electrician or engineer to know that lightning is a major cause of electrical interference and damage. Protecting the electrical system against such a danger is paramount. A lightning stroke can be hotter than the surface of the sun, with voltage estimated as high as 120 million volts, including 400 kA and 500 megajoules of energy. Utility …
Electrical Service Work and Worker Fatigue: Take Care of Yourself!
Chances are you are in an electrical career you love: Testing, maintaining, installing, commissioning, designing, rebuilding, engineering, improving…and generally making electrical power systems safer and better. But are you doing so with a focus on managing the possible onset of acute or chronic fatigue? We live in a busy world — do more with less; be efficient in your tasks; …
NFPA 70E — 2021 Edition: Second Draft Meeting Highlights and Summary
The second draft technical committee meeting for the 2021 Edition of NFPA 70E was held July 15–19, 2019 in Indianapolis, Indiana. The public comments submitted for committee action following the first draft meeting were discussed and voted on. NETA was represented at the meeting and participated in the actions. To remind everyone of the NFPA process for changes to a …
NETA World Keeps You One Step Ahead of Emerging Technology
Emerging technologies continually alter the way electrical testing is performed in the field. New technology can vary from more efficient ways to perform long-standing test routines to introducing a new test technology and just about everything in between. This issue’s authors share their knowledge of recent developments in the field of electrical testing. Fall is typically one of the busiest …
How Multi-Function Numerical Protection Relays Use Symmetrical Components
Multi-function protection relays calculate and use symmetrical components to enhance their performance during system faults. This can be illustrated in two specific examples: (1) zero-sequence current elimination for transformer differential protection and (2) negative-sequence current detection to inhibit out-of-step blocking. Zigzag Transformer Inside Transformer Differential Zone A shunt-connected zigzag transformer provides a zero-sequence current sink for ungrounded systems such as …
Arc Rated Clothing and Electrical Hazard Footwear
Everyone wears clothes, at least when out in public. However, not everyone needs to wear clothes specially designed and tested to protect them from hazards they could find in their workplace. If your employees work on or near electric power, generation, transmission, and distribution equipment, specialized clothing is necessary for certain tasks. OSHA 29 CFR 1910.269 states that employers must …
Using NFPA 70E to Stay Alive
This month’s Tech Quiz takes a bit different look at NFPA 70E requirements. What is involved in electrical testing? As with most things, it’s not as simple as it may seem. 1. If you are a crew leader, what is the first thing you would do to test a transformer? a. De-energize it b. Isolate it by lockout/tagout (LOTO) c. …