Practical Non-Invasive Partial Discharge Cable Testing

William G. Higinbotham Industry Topics, Spring 2021 Industry Topics

Partial discharge (PD) is a poorly understood phenomenon that can cause catastrophic failure of electrical assets. It can exist at initial commissioning or occur only after decades of use. The dictionary defines partial discharge as: a flashover of part of the insulation system due to a localized electric field greater than the dielectric withstand capability of that part where the …

Motor Control Centers

Rodrick J. Van Wart Industry Topics, Spring 2021 Industry Topics

Most electrical equipment manufacturers provide life and performance expectancies with their equipment in the form of operation and maintenance manuals. Life expectancy is based on the premise that equipment has been professionally installed, is maintained in accordance with the manufacturer’s guidelines and recommendations, and is being used per the manufacturer’s designed intent. This premise is also noted in NFPA 70 …

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 …

Power Quality, Reliability, and Sophisticated Automated Systems

Alan Ross Fall 2020 Industry Topics, Industry Topics

What do robotics, artificial intelligence (AI), automation, synaptic performance indicators (SPI), and machine learning (ML) have in common? In addition to being buzzwords for the reliability professional to throw around, the reliability world uses these terms to get practitioners to spend a lot of money on the shiny new thing. Sadly, too much of that money will be wasted by …

Protection Considerations for an Improperly Installed On-Load Tap Changer

Alex Rangel Fall 2020 Industry Topics, Industry Topics

Large power transformers are widely used in the electrical grid, and interconnecting solar farms to the utility is one of their many applications. To control voltage variations throughout the day, an on-load tap changer (OLTC) is used to adjust the number of effective windings to match the utility’s voltage. Proper functionality of the OLTC requires a specific sequence of operations, …

Improved Safety Method for Measuring Dead Tank Circuit Breaker Operation Time

Radenko Ostojić and Adnan Šečić Fall 2020 Industry Topics, Industry Topics

Safety in high-voltage substations is the highest priority for all personnel involved, and regulations and laws require all objects to be grounded on both sides before any maintenance work is performed. Failure to ground the circuit breaker (CB) on both sides creates risk of induced high voltages and currents at the ungrounded terminal. Eliminating this risk improves the safety of …

Best Practices for Safe Return to Service Following Maintenance Outage

Charles Mark McClung and Russell R. Safreed Industry Topics, Summer 2020 Industry Topics

Returning electrical equipment to service after a planned maintenance outage creates a unique set of hazards. Facility managers are under stringent time constraints when taking a system out of service, performing necessary maintenance tasks (as well as making unanticipated repairs), and returning the system to service. Common, real-world factors may place workers at great risk as the system is returned …