Power factor measurement has long been accepted as an invaluable tool for identifying insulation defects such as aging, deterioration, moisture ingress, and localized failures involving the winding and bushing insulation of a power transformer. Historically, power factor measurements have been performed at a single test frequency (typically 60Hz) and at a single test voltage (typically 10kV). However, modern test instruments …
High-Power Batteries as Power Source with Dynamic Resistance Measurement and Both Sides Grounded
Electrical arc phenomena have been studied for a long time. It is an inevitable process that occurs during interruption of high electrical currents (e.g., during a short circuit current interruption). The effects of the electrical arc on the circuit breaker contacts are known, and great attention has been paid to developing methods to analyze arc behavior and minimize damage to …
Dynamic Testing of Numerical Protection Relays
A numerical protection relay provides multiple functions and typically uses algorithms that do not work on the same principles as older electromechanical relays. Numerical relays are often still tested using old techniques developed long ago for electromechanical relays. One such common technique is referred to as a “static test.” Fault voltage and/or fault current are injected to see whether the …
Measuring Humidity: Why It’s Important
Most people are all too aware of the effects humidity can have on human comfort and health, especially when combined with high temperatures. Perhaps less well known is how humidity can impact electrical systems. For example, high humidity can cause droplets of water to condense on circuits, producing problems such as shorting and corrosion. Many geographic regions are prone to …
Sulfur Hexafluoride Gas Hazards
Sulfur hexafluoride, also known as SF6 gas, is a commonly used and excellent insulator found in many medium to large circuit breakers protecting transmission and distribution equipment. It has been argued that gas-filled breakers are superior to those filled with oil, air, or a vacuum. They operate cooler and with no noise or gas emissions and are considered relatively low …
Sulphur Hexafluoride Circuit Breakers
Sulphur hexafluoride circuit breakers used to be the domain of utilities, but they are liable to be used now by any large- or medium-size industrial. This Tech Quiz will review some of the NETA standard requirements for these circuit breakers. 1. In ANSI/NETA ATS, which ANSI/IEEE standard is referred to if manufacturer’s data is not available? a. C57.04 b. C57.11 …
Computer-Based Technology for Ground Testing
Since its inception in the early 20th century, testing grounded electrodes has been grounded on one technique and technology only: Fall of Potential. The test instrument made contact with the earth through long leads and driven probes, injected a current between the electrode being tested and a remote probe, and measured the voltage drop caused by earth resistance to another …
Testing Battery Banks
The 2021 NFPA 70E cycle started last year, and the Second Draft Meeting will convene July 14–19, 2019. One interesting benefit of being on the committee is the information that is shared with us. Some of it is obviously presented to serve one purpose or another, but some of it is put forward by well-known, independent laboratories that have no …
SF6—The Alternative Gas
With the ever-growing challenges of federal and local reporting and SF6 emission reduction, several alternatives have been presented to the industry as replacements for SF6 gas. As the industry continues to review and consider alternatives, we should not limit our solutions, and the alternative of turning to the existing stockpile of SF6 gas offers several benefits. However, what preventative measures …
The Best Place to Be—Welcome to PowerTest 2019
They say everything is bigger in Texas, and that’s what we are shooting for — huge venue, huge attendance, many vendors, and great presentations. That’s why I always look forward to PowerTest. It is without question the best place to be if you are in our industry or use our services. It’s great to see old friends and make new …