At 5:45 AM on a particularly cold winter day, an industrial manufacturing plant experienced a significant electrical fault event on a 15kV substation that feeds power to approximately 30% of the manufacturing operations. FAULT ON FEEDER M1A: WHAT HAPPENED? The main circuit breaker in one of the plant’s three medium-voltage substations experienced a fault, arc flash event, and subsequent trip …
In this issue of NETA World, we focus on medium-voltage circuit breaker test methods and the analysis of the resulting test data from those methods. Be sure to check out “Power Factoring Medium-Voltage Breakers” by Rick Youngblood of Electrical Maintenance & Testing and “The Why of Medium-Voltage Circuit Breaker Testing” by Paul Grein of Group CBS Testing for a good …
This edition of the Tech Quiz discusses one thing we all deal with, either at home or at work: low-voltage circuit breakers. Typically, they can last for years without causing problems, but they do require some maintenance and care. Continue on to find out what’s in store for you! 1. When the topic of low-voltage circuit breakers comes up, what …
Falls from ladders account for 20% of all fatalities and lost-workday injuries in general industry according to Occupational Safety and Health Administration (OSHA) statistics. Ensuring that all ladders meet OSHA and American National Standards Institute (ANSI) standards is critical in mitigating this statistic. OSHA Regulatory Requirements OSHA published an update to its walking-working surface rule (Subpart D) for general industry …
Emergencies always seem to occur on Fridays and weekends, and true to form, a panicked customer called about a power outage to a significant portion of a college campus on a Friday morning. It seemed likely to be a 4,160 volt cable or unit substation problem, so we pulled two technicians away from an acceptance testing project and got them on …
Multi-function numerical generator protection relays can calculate the insulation resistance of a synchronous generator field winding to ground. The calculation can be performed on an energized or de-energized generator. The particular relay discussed in this article uses a separate module located close to the rotor slip rings and brushes to monitor the field. The close proximity of the module to …
This issue of NETA World continues with the deep dive into the NFPA 70E revisions that went into the 2021 edition. Part 1 in the Winter 2020 issue covered the reorganization (which was not nearly as extensive as in previous editions); reviewed Article 100 Definitions; and began on Article 110 General Requirements for Electrical Safety-Related Work Practices with Section 110.1 …
It is January 20, 2021, and the country is in the midst of a resurgence of the COVID-19 virus. The Conference Committee, in consultation with the NETA Board of Directors, has decided to go totally virtual with PowerTest 2021, the premier electrical maintenance and safety conference intended for all electrical professionals and especially beneficial for field service technicians, inspectors, utility …
Although it can readily be overlooked, an important and fundamental consideration in any electrical application is safety, and one of the most effective tools in the application of safety is redundancy. If one safeguard fails, there’s another right there to act as a safety net. There’s hardly a greater necessity for redundant safety than in a substation, where arcing could …
Effective ground testing is an informed combination of instrumentation and procedure. Accuracy, resolution, safety, noise suppression, graphics, clamp features, and general reliability are all critical, as they are with any electrical testing. But effective and accurate ground testing depends as much on adherence to procedure as it does on quality of instrumentation. If the operator does not understand and diligently …