Challenges in Transformer Protection Testing

Scott Cooper Cover Story, Winter 2020 Cover Story

While the basic premise of transformer differential protection is straightforward, numerous features are employed in modern relay algorithms to compensate for challenges presented by the transformer differential application. As a result, developing appropriate test quantities and properly quantifying results can be challenging with traditional functional differential testing. Challenges in Traditional Functional Testing A traditional functional test assures that all measurements …

PF Measurements On Complete Stator Windings

Mathieu Lachance CAP Corner, Winter 2020 CAP Corner

Power factor (PF) measurement has been performed on stator windings for many decades and is a widely accepted and recommended tool to assess the insulation system of individual bars/coils and for complete stator windings. The test is known to be sensitive to several global defects such as the degree of curing of the bonding materials, moisture ingress, contamination, and thermal …

AEMC® Instruments: Over 125 Years of Technical Heritage and Innovation in Test Instrumentation

NETA World Staff CAP Corner, Winter 2020 CAP Corner

NETA Corporate Alliance Partners (CAPs) are a group of industry-leading companies that have joined forces with NETA to work together toward a common aim: improving quality, safety, and electrical system reliability. In our continuing CAP Spotlight series, we highlight some of their individual successes. In this issue, NETA World interviews John Olobri, Director of Sales and Marketing for AEMC® Instruments …

ANSI/NETA Standards Update

NETA World Staff Specifications & Standards, Winter 2020 Specifications & Standards

ANSI/NETA ATS–2017 Revision Underway ANSI/NETA ATS–2017, Standard for Acceptance Testing Specifications for Electrical Power Equipment & Systems continues an American National Standard revision process that is scheduled to be completed by the end of 2020. The new edition will be released in March 2021. A project intent notification published in ANSI’s Standards Action on January 3, 2020, announced the opening …

Impact of SFRA Setup Issues on Transformer Frequency Response

Michael D. Wolf Industry Topics, Winter 2020 Industry Topics

Sweep frequency response analysis (SFRA) is a popular test to confirm the mechanical and electrical integrity of a transformer. However, the resulting traces can be difficult for field personnel to interpret due to the visual nature of the data. It is more straightforward to compare numbers against prior data or against a stated limit than to interpret subtle differences in …

Understanding and Avoiding Battery Failure

Rodrick J. Van Wart Industry Topics, Winter 2020 Industry Topics

Earthquakes, hurricanes, tsunamis, wildfires, and the like do not occur with any predicted great frequency. Nonetheless, we have established precautionary programs that protect people and property from the physical threats posed by such events. In recent times, however, we have witnessed all too well the impact these events can have on the quality of our lives and businesses. Our world …

Ground Testing Procedures

Jeffrey R. Jowett Columns, Tech Tips, Winter 2020 Columns

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 …

Protective Relaying

James R. White Columns, Tech Quiz, Winter 2020 Columns

This edition of Tech Quiz covers protective relays. Many years ago, as I was teaching a protective relay class, a student asked, “What are these things?” I replied, “Relays,” to which he answered, “No, relays are those little black plastic things that go click-click.” I made sure to call them protective relays from then on. Things in the protective relaying …

Basic Fall Protection

Paul Chamberlain Columns, Safety Corner, Winter 2020 Columns

Fall protection requirements and equipment varies depending upon where the work is being performed. The regulations can be confusing for some employees, so it is up to the manager or safety professional to understand the work, the environment the work is being performed in, and the equipment needed to mitigate the hazard of falling from height. When Is Protection Required? …

Combustion Turbine Generator Trip Analysis

Steve Turner Columns, Relay Column, Winter 2020 Columns

Relay personnel responsible for testing protective relays are often called upon to troubleshoot and gather system data such as settings and event recordings when a major event occurs (for this example, a large generator trip). If only electromechanical relays are installed and no digital fault recorder is available, it can be difficult to determine the root cause of the trip …