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
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
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
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 …
Is Your Arc-in-Oil Load Tap Changer Due for Maintenance?
A load tap changer (LTC) failure can be catastrophic to the electric power system. The load tap changer (LTC) is one of the few moving parts of a transformer, and this makes it more susceptible to routine wear and tear. When an LTC fails, it may take the transformer with it. Based on our experience, we estimate that about 40 …
Medium-Voltage Asset Failure Investigations
Medium-voltage cables are an integral part of modern power systems and have existed for over 100 years in various forms. Over the past 50 years, extruded cables have largely displaced paper insulated cables. Extruded cables offer many advantages over older designs, but are similarly prone to failure. Such failures are a significant impediment to improving overall power system reliability. Since …
A New Way to Test Distribution Automation Schemes
With an ever-growing demand for a more reliable distribution grid, utilities are constantly looking for possibilities to optimize their distribution networks by implementing distribution automation. One method to improve the network and reduce permanent outages is using pole-mounted reclosers, due to their wide range of functionality. By introducing built-in voltage sensing on both source and load sides, automation can easily …
Ensure Effective Acceptance and Maintenance Testing with Quality Reporting and Analysis
Coming up through the ranks in the power industry, I quickly realized I didn’t know what I didn’t know! There are so many facets of the power industry: generation, protection and controls, distribution and delivery, reliability, drives, uninterruptable power supplies, system studies, safety, maintenance, testing, as well as other areas that are vital for the safe and reliable delivery and …
Three Tips to Reduce Wasted Time When Testing Transformers
Performing offline electrical tests on transformers can be time consuming, especially when field measurements are not captured correctly the first time. This article identifies the electrical transformer test that technicians often struggle to perform efficiently and correctly and offers three field testing tips to address the issue. Building awareness can help test equipment users avoid situations where a significant amount …
Using Measurement Results to Diagnose the Condition of High-Voltage Rotating Machines —Part 2
Diagnosing the condition of complex systems such as high-voltage rotating machines has never been a simple task. Design requirements, the use of different materials, and demanding operating conditions require multiple off-line tests and on-line monitors to provide information on the machine’s condition. Part 1 of this article described the application of various off-line test techniques to assess stator and rotor …
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